1 # SOME DESCRIPTIVE TITLE
2 # Copyright (C) YEAR Free Software Foundation, Inc.
3 # This file is distributed under the same license as the PACKAGE package.
4 # FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
9 "Project-Id-Version: PACKAGE VERSION\n"
10 "POT-Creation-Date: 2013-03-22 01:06+0900\n"
11 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
12 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
13 "Language-Team: LANGUAGE <LL@li.org>\n"
16 "Content-Type: text/plain; charset=UTF-8\n"
17 "Content-Transfer-Encoding: 8bit\n"
20 #: build/C/man2/acct.2:31 build/C/man5/acct.5:25
26 #: build/C/man2/acct.2:31
32 #: build/C/man2/acct.2:31 build/C/man5/acct.5:25 build/C/man7/capabilities.7:48 build/C/man2/capget.2:15 build/C/man7/cpuset.7:25 build/C/man7/credentials.7:27 build/C/man2/getgid.2:25 build/C/man2/getgroups.2:31 build/C/man2/getpid.2:25 build/C/man2/getpriority.2:48 build/C/man2/getresuid.2:28 build/C/man2/getrlimit.2:64 build/C/man2/getrusage.2:39 build/C/man2/getsid.2:26 build/C/man2/getuid.2:26 build/C/man2/iopl.2:33 build/C/man2/ioprio_set.2:24 build/C/man2/ipc.2:25 build/C/man2/seteuid.2:29 build/C/man2/setfsgid.2:31 build/C/man2/setfsuid.2:31 build/C/man2/setgid.2:29 build/C/man2/setpgid.2:48 build/C/man2/setresuid.2:26 build/C/man2/setreuid.2:45 build/C/man2/setsid.2:30 build/C/man2/setuid.2:30 build/C/man7/svipc.7:27 build/C/man3/ulimit.3:27
38 #: build/C/man2/acct.2:31 build/C/man5/acct.5:25 build/C/man7/capabilities.7:48 build/C/man2/capget.2:15 build/C/man7/cpuset.7:25 build/C/man7/credentials.7:27 build/C/man2/getgid.2:25 build/C/man2/getgroups.2:31 build/C/man2/getpid.2:25 build/C/man2/getpriority.2:48 build/C/man2/getresuid.2:28 build/C/man2/getrlimit.2:64 build/C/man2/getrusage.2:39 build/C/man2/getsid.2:26 build/C/man2/getuid.2:26 build/C/man2/iopl.2:33 build/C/man2/ioprio_set.2:24 build/C/man2/ipc.2:25 build/C/man2/seteuid.2:29 build/C/man2/setfsgid.2:31 build/C/man2/setfsuid.2:31 build/C/man2/setgid.2:29 build/C/man2/setpgid.2:48 build/C/man2/setresuid.2:26 build/C/man2/setreuid.2:45 build/C/man2/setsid.2:30 build/C/man2/setuid.2:30 build/C/man7/svipc.7:27 build/C/man3/ulimit.3:27
40 msgid "Linux Programmer's Manual"
44 #: build/C/man2/acct.2:32 build/C/man5/acct.5:26 build/C/man7/capabilities.7:49 build/C/man2/capget.2:16 build/C/man7/cpuset.7:26 build/C/man7/credentials.7:28 build/C/man2/getgid.2:26 build/C/man2/getgroups.2:32 build/C/man2/getpid.2:26 build/C/man2/getpriority.2:49 build/C/man2/getresuid.2:29 build/C/man2/getrlimit.2:65 build/C/man2/getrusage.2:40 build/C/man2/getsid.2:27 build/C/man2/getuid.2:27 build/C/man2/iopl.2:34 build/C/man2/ioprio_set.2:25 build/C/man2/ipc.2:26 build/C/man2/seteuid.2:30 build/C/man2/setfsgid.2:32 build/C/man2/setfsuid.2:32 build/C/man2/setgid.2:30 build/C/man2/setpgid.2:49 build/C/man2/setresuid.2:27 build/C/man2/setreuid.2:46 build/C/man2/setsid.2:31 build/C/man2/setuid.2:31 build/C/man7/svipc.7:28 build/C/man3/ulimit.3:28
50 #: build/C/man2/acct.2:34
51 msgid "acct - switch process accounting on or off"
55 #: build/C/man2/acct.2:34 build/C/man5/acct.5:28 build/C/man2/capget.2:18 build/C/man2/getgid.2:28 build/C/man2/getgroups.2:34 build/C/man2/getpid.2:28 build/C/man2/getpriority.2:51 build/C/man2/getresuid.2:31 build/C/man2/getrlimit.2:67 build/C/man2/getrusage.2:42 build/C/man2/getsid.2:29 build/C/man2/getuid.2:29 build/C/man2/iopl.2:36 build/C/man2/ioprio_set.2:27 build/C/man2/ipc.2:28 build/C/man2/seteuid.2:32 build/C/man2/setfsgid.2:34 build/C/man2/setfsuid.2:34 build/C/man2/setgid.2:32 build/C/man2/setpgid.2:51 build/C/man2/setresuid.2:29 build/C/man2/setreuid.2:48 build/C/man2/setsid.2:33 build/C/man2/setuid.2:33 build/C/man7/svipc.7:30 build/C/man3/ulimit.3:30
61 #: build/C/man2/acct.2:38
63 msgid "B<#include E<lt>unistd.hE<gt>>\n"
67 #: build/C/man2/acct.2:40
69 msgid "B<int acct(const char *>I<filename>B<);>\n"
73 #: build/C/man2/acct.2:46 build/C/man2/getgroups.2:48 build/C/man2/getrlimit.2:84 build/C/man2/getsid.2:37 build/C/man2/seteuid.2:44 build/C/man2/setpgid.2:71 build/C/man2/setreuid.2:60
74 msgid "Feature Test Macro Requirements for glibc (see B<feature_test_macros>(7)):"
78 #: build/C/man2/acct.2:50
79 msgid "B<acct>(): _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE\\ E<lt>\\ 500)"
83 #: build/C/man2/acct.2:50 build/C/man5/acct.5:30 build/C/man7/capabilities.7:51 build/C/man2/capget.2:24 build/C/man7/cpuset.7:28 build/C/man7/credentials.7:30 build/C/man2/getgid.2:36 build/C/man2/getgroups.2:52 build/C/man2/getpid.2:36 build/C/man2/getpriority.2:59 build/C/man2/getresuid.2:39 build/C/man2/getrlimit.2:88 build/C/man2/getrusage.2:48 build/C/man2/getsid.2:50 build/C/man2/getuid.2:37 build/C/man2/iopl.2:40 build/C/man2/ioprio_set.2:35 build/C/man2/ipc.2:34 build/C/man2/seteuid.2:53 build/C/man2/setfsgid.2:39 build/C/man2/setfsuid.2:39 build/C/man2/setgid.2:38 build/C/man2/setpgid.2:98 build/C/man2/setresuid.2:37 build/C/man2/setreuid.2:70 build/C/man2/setsid.2:40 build/C/man2/setuid.2:39 build/C/man7/svipc.7:36 build/C/man3/ulimit.3:34
89 #: build/C/man2/acct.2:59
91 "The B<acct>() system call enables or disables process accounting. If "
92 "called with the name of an existing file as its argument, accounting is "
93 "turned on, and records for each terminating process are appended to "
94 "I<filename> as it terminates. An argument of NULL causes accounting to be "
99 #: build/C/man2/acct.2:59 build/C/man2/capget.2:160 build/C/man2/getgroups.2:92 build/C/man2/getpriority.2:107 build/C/man2/getresuid.2:50 build/C/man2/getrlimit.2:430 build/C/man2/getrusage.2:180 build/C/man2/getsid.2:58 build/C/man2/iopl.2:66 build/C/man2/ioprio_set.2:149 build/C/man2/seteuid.2:67 build/C/man2/setfsgid.2:69 build/C/man2/setfsuid.2:69 build/C/man2/setgid.2:53 build/C/man2/setpgid.2:172 build/C/man2/setresuid.2:64 build/C/man2/setreuid.2:91 build/C/man2/setsid.2:51 build/C/man2/setuid.2:70 build/C/man3/ulimit.3:67
105 #: build/C/man2/acct.2:64 build/C/man2/capget.2:165 build/C/man2/getresuid.2:55 build/C/man2/getrusage.2:185 build/C/man2/iopl.2:71 build/C/man2/seteuid.2:72 build/C/man2/setgid.2:58 build/C/man2/setresuid.2:69 build/C/man2/setreuid.2:96 build/C/man2/setuid.2:75
107 "On success, zero is returned. On error, -1 is returned, and I<errno> is set "
112 #: build/C/man2/acct.2:64 build/C/man2/capget.2:179 build/C/man7/cpuset.7:1100 build/C/man2/getgid.2:42 build/C/man2/getgroups.2:106 build/C/man2/getpid.2:44 build/C/man2/getpriority.2:120 build/C/man2/getresuid.2:55 build/C/man2/getrlimit.2:435 build/C/man2/getrusage.2:185 build/C/man2/getsid.2:63 build/C/man2/getuid.2:43 build/C/man2/iopl.2:71 build/C/man2/ioprio_set.2:169 build/C/man2/seteuid.2:72 build/C/man2/setgid.2:58 build/C/man2/setpgid.2:193 build/C/man2/setresuid.2:69 build/C/man2/setreuid.2:96 build/C/man2/setsid.2:58 build/C/man2/setuid.2:75 build/C/man3/ulimit.3:74
118 #: build/C/man2/acct.2:65 build/C/man7/cpuset.7:1116 build/C/man7/cpuset.7:1123 build/C/man7/cpuset.7:1129 build/C/man7/cpuset.7:1137 build/C/man7/cpuset.7:1144 build/C/man2/getpriority.2:140 build/C/man2/setpgid.2:194
124 #: build/C/man2/acct.2:76
126 "Write permission is denied for the specified file, or search permission is "
127 "denied for one of the directories in the path prefix of I<filename> (see "
128 "also B<path_resolution>(7)), or I<filename> is not a regular file."
132 #: build/C/man2/acct.2:76 build/C/man2/capget.2:180 build/C/man7/cpuset.7:1172 build/C/man2/getgroups.2:107 build/C/man2/getresuid.2:56 build/C/man2/getrlimit.2:436 build/C/man2/getrusage.2:186
138 #: build/C/man2/acct.2:80
139 msgid "I<filename> points outside your accessible address space."
143 #: build/C/man2/acct.2:80 build/C/man7/cpuset.7:1238 build/C/man7/cpuset.7:1246
149 #: build/C/man2/acct.2:84
150 msgid "Error writing to the file I<filename>."
154 #: build/C/man2/acct.2:84
160 #: build/C/man2/acct.2:88
161 msgid "I<filename> is a directory."
165 #: build/C/man2/acct.2:88
171 #: build/C/man2/acct.2:92
172 msgid "Too many symbolic links were encountered in resolving I<filename>."
176 #: build/C/man2/acct.2:92 build/C/man7/cpuset.7:1251 build/C/man7/cpuset.7:1258 build/C/man7/cpuset.7:1263
178 msgid "B<ENAMETOOLONG>"
182 #: build/C/man2/acct.2:96
183 msgid "I<filename> was too long."
187 #: build/C/man2/acct.2:96
193 #: build/C/man2/acct.2:99
194 msgid "The system limit on the total number of open files has been reached."
198 #: build/C/man2/acct.2:99 build/C/man7/cpuset.7:1275 build/C/man7/cpuset.7:1280
204 #: build/C/man2/acct.2:102
205 msgid "The specified filename does not exist."
209 #: build/C/man2/acct.2:102 build/C/man7/cpuset.7:1287 build/C/man2/getgroups.2:127
215 #: build/C/man2/acct.2:105 build/C/man2/getgroups.2:130
216 msgid "Out of memory."
220 #: build/C/man2/acct.2:105 build/C/man2/iopl.2:76
226 #: build/C/man2/acct.2:111
228 "BSD process accounting has not been enabled when the operating system kernel "
229 "was compiled. The kernel configuration parameter controlling this feature "
230 "is B<CONFIG_BSD_PROCESS_ACCT>."
234 #: build/C/man2/acct.2:111 build/C/man7/cpuset.7:1314
240 #: build/C/man2/acct.2:116
241 msgid "A component used as a directory in I<filename> is not in fact a directory."
245 #: build/C/man2/acct.2:116 build/C/man2/capget.2:191 build/C/man2/capget.2:196 build/C/man7/cpuset.7:1319 build/C/man2/getgroups.2:130 build/C/man2/getpriority.2:152 build/C/man2/getrlimit.2:452 build/C/man2/getsid.2:64 build/C/man2/iopl.2:79 build/C/man2/ioprio_set.2:179 build/C/man2/seteuid.2:75 build/C/man2/setgid.2:59 build/C/man2/setpgid.2:208 build/C/man2/setresuid.2:77 build/C/man2/setreuid.2:97 build/C/man2/setsid.2:59 build/C/man2/setuid.2:85 build/C/man3/ulimit.3:75
251 #: build/C/man2/acct.2:122
253 "The calling process has insufficient privilege to enable process "
254 "accounting. On Linux the B<CAP_SYS_PACCT> capability is required."
258 #: build/C/man2/acct.2:122
264 #: build/C/man2/acct.2:126
265 msgid "I<filename> refers to a file on a read-only file system."
269 #: build/C/man2/acct.2:126
275 #: build/C/man2/acct.2:129
276 msgid "There are no more free file structures or we ran out of memory."
280 #: build/C/man2/acct.2:129 build/C/man5/acct.5:153 build/C/man7/capabilities.7:1061 build/C/man2/capget.2:218 build/C/man7/credentials.7:234 build/C/man2/getgid.2:44 build/C/man2/getgroups.2:133 build/C/man2/getpid.2:46 build/C/man2/getpriority.2:160 build/C/man2/getresuid.2:67 build/C/man2/getrlimit.2:473 build/C/man2/getrusage.2:194 build/C/man2/getsid.2:79 build/C/man2/getuid.2:45 build/C/man2/iopl.2:87 build/C/man2/ioprio_set.2:196 build/C/man2/ipc.2:45 build/C/man2/seteuid.2:91 build/C/man2/setfsgid.2:80 build/C/man2/setfsuid.2:80 build/C/man2/setgid.2:66 build/C/man2/setpgid.2:227 build/C/man2/setresuid.2:83 build/C/man2/setreuid.2:113 build/C/man2/setsid.2:65 build/C/man2/setuid.2:92 build/C/man3/ulimit.3:78
282 msgid "CONFORMING TO"
285 #. SVr4 documents an EBUSY error condition, but no EISDIR or ENOSYS.
286 #. Also AIX and HP-UX document EBUSY (attempt is made
287 #. to enable accounting when it is already enabled), as does Solaris
288 #. (attempt is made to enable accounting using the same file that is
289 #. currently being used).
291 #: build/C/man2/acct.2:136
292 msgid "SVr4, 4.3BSD (but not POSIX)."
296 #: build/C/man2/acct.2:136 build/C/man5/acct.5:157 build/C/man7/capabilities.7:1067 build/C/man2/capget.2:220 build/C/man7/cpuset.7:1341 build/C/man7/credentials.7:240 build/C/man2/getgid.2:46 build/C/man2/getgroups.2:141 build/C/man2/getpid.2:48 build/C/man2/getpriority.2:163 build/C/man2/getresuid.2:70 build/C/man2/getrlimit.2:496 build/C/man2/getrusage.2:205 build/C/man2/getsid.2:81 build/C/man2/getuid.2:47 build/C/man2/iopl.2:91 build/C/man2/ioprio_set.2:198 build/C/man2/ipc.2:49 build/C/man2/seteuid.2:93 build/C/man2/setfsgid.2:84 build/C/man2/setfsuid.2:84 build/C/man2/setgid.2:68 build/C/man2/setpgid.2:249 build/C/man2/setresuid.2:86 build/C/man2/setreuid.2:119 build/C/man2/setsid.2:67 build/C/man2/setuid.2:97
302 #: build/C/man2/acct.2:139
304 "No accounting is produced for programs running when a system crash occurs. "
305 "In particular, nonterminating processes are never accounted for."
309 #: build/C/man2/acct.2:142
311 "The structure of the records written to the accounting file is described in "
316 #: build/C/man2/acct.2:142 build/C/man5/acct.5:174 build/C/man7/capabilities.7:1123 build/C/man2/capget.2:228 build/C/man7/cpuset.7:1488 build/C/man7/credentials.7:251 build/C/man2/getgid.2:62 build/C/man2/getgroups.2:171 build/C/man2/getpid.2:100 build/C/man2/getpriority.2:232 build/C/man2/getresuid.2:86 build/C/man2/getrlimit.2:656 build/C/man2/getrusage.2:245 build/C/man2/getsid.2:84 build/C/man2/getuid.2:73 build/C/man2/iopl.2:100 build/C/man2/ioprio_set.2:346 build/C/man2/ipc.2:57 build/C/man2/seteuid.2:124 build/C/man2/setfsgid.2:112 build/C/man2/setfsuid.2:112 build/C/man2/setgid.2:78 build/C/man2/setpgid.2:317 build/C/man2/setresuid.2:106 build/C/man2/setreuid.2:159 build/C/man2/setsid.2:84 build/C/man2/setuid.2:120 build/C/man7/svipc.7:318 build/C/man3/ulimit.3:83
322 #: build/C/man2/acct.2:144
327 #: build/C/man2/acct.2:144 build/C/man5/acct.5:179 build/C/man7/capabilities.7:1143 build/C/man2/capget.2:232 build/C/man7/cpuset.7:1505 build/C/man7/credentials.7:282 build/C/man2/getgid.2:67 build/C/man2/getgroups.2:178 build/C/man2/getpid.2:110 build/C/man2/getpriority.2:240 build/C/man2/getresuid.2:92 build/C/man2/getrlimit.2:674 build/C/man2/getrusage.2:252 build/C/man2/getsid.2:88 build/C/man2/getuid.2:78 build/C/man2/iopl.2:104 build/C/man2/ioprio_set.2:354 build/C/man2/ipc.2:70 build/C/man2/seteuid.2:131 build/C/man2/setfsgid.2:117 build/C/man2/setfsuid.2:117 build/C/man2/setgid.2:84 build/C/man2/setpgid.2:324 build/C/man2/setresuid.2:115 build/C/man2/setreuid.2:167 build/C/man2/setsid.2:91 build/C/man2/setuid.2:127 build/C/man7/svipc.7:335 build/C/man3/ulimit.3:88
333 #: build/C/man2/acct.2:151 build/C/man5/acct.5:186 build/C/man7/capabilities.7:1150 build/C/man2/capget.2:239 build/C/man7/cpuset.7:1512 build/C/man7/credentials.7:289 build/C/man2/getgid.2:74 build/C/man2/getgroups.2:185 build/C/man2/getpid.2:117 build/C/man2/getpriority.2:247 build/C/man2/getresuid.2:99 build/C/man2/getrlimit.2:681 build/C/man2/getrusage.2:259 build/C/man2/getsid.2:95 build/C/man2/getuid.2:85 build/C/man2/iopl.2:111 build/C/man2/ioprio_set.2:361 build/C/man2/ipc.2:77 build/C/man2/seteuid.2:138 build/C/man2/setfsgid.2:124 build/C/man2/setfsuid.2:124 build/C/man2/setgid.2:91 build/C/man2/setpgid.2:331 build/C/man2/setresuid.2:122 build/C/man2/setreuid.2:174 build/C/man2/setsid.2:98 build/C/man2/setuid.2:134 build/C/man7/svipc.7:342 build/C/man3/ulimit.3:95
335 "This page is part of release 3.50 of the Linux I<man-pages> project. A "
336 "description of the project, and information about reporting bugs, can be "
337 "found at http://www.kernel.org/doc/man-pages/."
341 #: build/C/man5/acct.5:25
347 #: build/C/man5/acct.5:28
348 msgid "acct - process accounting file"
352 #: build/C/man5/acct.5:30
353 msgid "B<#include E<lt>sys/acct.hE<gt>>"
357 #: build/C/man5/acct.5:36
359 "If the kernel is built with the process accounting option enabled "
360 "(B<CONFIG_BSD_PROCESS_ACCT>), then calling B<acct>(2) starts process "
361 "accounting, for example:"
365 #: build/C/man5/acct.5:39
366 msgid "acct(\"/var/log/pacct\");"
370 #: build/C/man5/acct.5:47
372 "When process accounting is enabled, the kernel writes a record to the "
373 "accounting file as each process on the system terminates. This record "
374 "contains information about the terminated process, and is defined in "
375 "I<E<lt>sys/acct.hE<gt>> as follows:"
379 #: build/C/man5/acct.5:51
381 msgid "#define ACCT_COMM 16\n"
385 #: build/C/man5/acct.5:53
387 msgid "typedef u_int16_t comp_t;\n"
391 #: build/C/man5/acct.5:77
395 " char ac_flag; /* Accounting flags */\n"
396 " u_int16_t ac_uid; /* Accounting user ID */\n"
397 " u_int16_t ac_gid; /* Accounting group ID */\n"
398 " u_int16_t ac_tty; /* Controlling terminal */\n"
399 " u_int32_t ac_btime; /* Process creation time\n"
400 " (seconds since the Epoch) */\n"
401 " comp_t ac_utime; /* User CPU time */\n"
402 " comp_t ac_stime; /* System CPU time */\n"
403 " comp_t ac_etime; /* Elapsed time */\n"
404 " comp_t ac_mem; /* Average memory usage (kB) */\n"
405 " comp_t ac_io; /* Characters transferred (unused) */\n"
406 " comp_t ac_rw; /* Blocks read or written (unused) */\n"
407 " comp_t ac_minflt; /* Minor page faults */\n"
408 " comp_t ac_majflt; /* Major page faults */\n"
409 " comp_t ac_swaps; /* Number of swaps (unused) */\n"
410 " u_int32_t ac_exitcode; /* Process termination status\n"
411 " (see wait(2)) */\n"
412 " char ac_comm[ACCT_COMM+1];\n"
413 " /* Command name (basename of last\n"
414 " executed command; null-terminated) */\n"
415 " char ac_pad[I<X>]; /* padding bytes */\n"
420 #: build/C/man5/acct.5:84
423 "enum { /* Bits that may be set in ac_flag field */\n"
424 " AFORK = 0x01, /* Has executed fork, but no exec */\n"
425 " ASU = 0x02, /* Used superuser privileges */\n"
426 " ACORE = 0x08, /* Dumped core */\n"
427 " AXSIG = 0x10 /* Killed by a signal */\n"
432 #: build/C/man5/acct.5:94
434 "The I<comp_t> data type is a floating-point value consisting of a 3-bit, "
435 "base-8 exponent, and a 13-bit mantissa. A value, I<c>, of this type can be "
436 "converted to a (long) integer as follows:"
440 #: build/C/man5/acct.5:97
442 msgid " v = (c & 0x1fff) E<lt>E<lt> (((c E<gt>E<gt> 13) & 0x7) * 3);\n"
446 #: build/C/man5/acct.5:107
448 "The I<ac_utime>, I<ac_stime>, and I<ac_etime> fields measure time in \"clock "
449 "ticks\"; divide these values by I<sysconf(_SC_CLK_TCK)> to convert them to "
454 #: build/C/man5/acct.5:107
456 msgid "Version 3 accounting file format"
460 #: build/C/man5/acct.5:122
462 "Since kernel 2.6.8, an optional alternative version of the accounting file "
463 "can be produced if the B<CONFIG_BSD_PROCESS_ACCT_V3> option is set when "
464 "building the kernel. With this option is set, the records written to the "
465 "accounting file contain additional fields, and the width of I<c_uid> and "
466 "I<ac_gid> fields is widened from 16 to 32 bits (in line with the increased "
467 "size of UID and GIDs in Linux 2.4 and later). The records are defined as "
472 #: build/C/man5/acct.5:147
476 " char ac_flag; /* Flags */\n"
477 " char ac_version; /* Always set to ACCT_VERSION (3) */\n"
478 " u_int16_t ac_tty; /* Controlling terminal */\n"
479 " u_int32_t ac_exitcode; /* Process termination status */\n"
480 " u_int32_t ac_uid; /* Real user ID */\n"
481 " u_int32_t ac_gid; /* Real group ID */\n"
482 " u_int32_t ac_pid; /* Process ID */\n"
483 " u_int32_t ac_ppid; /* Parent process ID */\n"
484 " u_int32_t ac_btime; /* Process creation time */\n"
485 " float ac_etime; /* Elapsed time */\n"
486 " comp_t ac_utime; /* User CPU time */\n"
487 " comp_t ac_stime; /* System time */\n"
488 " comp_t ac_mem; /* Average memory usage (kB) */\n"
489 " comp_t ac_io; /* Characters transferred (unused) */\n"
490 " comp_t ac_rw; /* Blocks read or written\n"
492 " comp_t ac_minflt; /* Minor page faults */\n"
493 " comp_t ac_majflt; /* Major page faults */\n"
494 " comp_t ac_swaps; /* Number of swaps (unused) */\n"
495 " char ac_comm[ACCT_COMM]; /* Command name */\n"
500 #: build/C/man5/acct.5:149 build/C/man7/cpuset.7:1338 build/C/man2/getresuid.2:60 build/C/man2/getrlimit.2:468 build/C/man2/getsid.2:75 build/C/man2/ioprio_set.2:193 build/C/man2/setfsgid.2:76 build/C/man2/setfsuid.2:76 build/C/man2/setresuid.2:81
506 #: build/C/man5/acct.5:153
507 msgid "The I<acct_v3> structure is defined in glibc since version 2.6."
511 #: build/C/man5/acct.5:157
513 "Process accounting originated on BSD. Although it is present on most "
514 "systems, it is not standardized, and the details vary somewhat between "
519 #: build/C/man5/acct.5:160
521 "Records in the accounting file are ordered by termination time of the "
526 #: build/C/man5/acct.5:167
528 "In kernels up to and including 2.6.9, a separate accounting record is "
529 "written for each thread created using the NPTL threading library; since "
530 "Linux 2.6.10, a single accounting record is written for the entire process "
531 "on termination of the last thread in the process."
535 #: build/C/man5/acct.5:174
537 "The I<proc/sys/kernel/acct> file, described in B<proc>(5), defines settings "
538 "that control the behavior of process accounting when disk space runs low."
542 #: build/C/man5/acct.5:179
543 msgid "B<lastcomm>(1), B<acct>(2), B<accton>(8), B<sa>(8)"
547 #: build/C/man7/capabilities.7:48
553 #: build/C/man7/capabilities.7:48 build/C/man2/capget.2:15
559 #: build/C/man7/capabilities.7:51
560 msgid "capabilities - overview of Linux capabilities"
564 #: build/C/man7/capabilities.7:63
566 "For the purpose of performing permission checks, traditional UNIX "
567 "implementations distinguish two categories of processes: I<privileged> "
568 "processes (whose effective user ID is 0, referred to as superuser or root), "
569 "and I<unprivileged> processes (whose effective UID is nonzero). Privileged "
570 "processes bypass all kernel permission checks, while unprivileged processes "
571 "are subject to full permission checking based on the process's credentials "
572 "(usually: effective UID, effective GID, and supplementary group list)."
576 #: build/C/man7/capabilities.7:70
578 "Starting with kernel 2.2, Linux divides the privileges traditionally "
579 "associated with superuser into distinct units, known as I<capabilities>, "
580 "which can be independently enabled and disabled. Capabilities are a "
581 "per-thread attribute."
585 #: build/C/man7/capabilities.7:70
587 msgid "Capabilities list"
591 #: build/C/man7/capabilities.7:73
593 "The following list shows the capabilities implemented on Linux, and the "
594 "operations or behaviors that each capability permits:"
598 #: build/C/man7/capabilities.7:73
600 msgid "B<CAP_AUDIT_CONTROL> (since Linux 2.6.11)"
604 #: build/C/man7/capabilities.7:77
606 "Enable and disable kernel auditing; change auditing filter rules; retrieve "
607 "auditing status and filtering rules."
611 #: build/C/man7/capabilities.7:77
613 msgid "B<CAP_AUDIT_WRITE> (since Linux 2.6.11)"
617 #: build/C/man7/capabilities.7:80
618 msgid "Write records to kernel auditing log."
622 #: build/C/man7/capabilities.7:80
624 msgid "B<CAP_BLOCK_SUSPEND> (since Linux 3.5)"
628 #: build/C/man7/capabilities.7:86
630 "Employ features that can block system suspend (B<epoll>(7) B<EPOLLWAKEUP>, "
631 "I</proc/sys/wake_lock>)."
635 #: build/C/man7/capabilities.7:86
641 #: build/C/man7/capabilities.7:90
642 msgid "Make arbitrary changes to file UIDs and GIDs (see B<chown>(2))."
646 #: build/C/man7/capabilities.7:90
648 msgid "B<CAP_DAC_OVERRIDE>"
652 #: build/C/man7/capabilities.7:94
654 "Bypass file read, write, and execute permission checks. (DAC is an "
655 "abbreviation of \"discretionary access control\".)"
659 #: build/C/man7/capabilities.7:94
661 msgid "B<CAP_DAC_READ_SEARCH>"
665 #: build/C/man7/capabilities.7:98
667 "Bypass file read permission checks and directory read and execute permission "
672 #: build/C/man7/capabilities.7:98
674 msgid "B<CAP_FOWNER>"
678 #: build/C/man7/capabilities.7:102 build/C/man7/capabilities.7:112 build/C/man7/capabilities.7:116 build/C/man7/capabilities.7:118 build/C/man7/capabilities.7:120 build/C/man7/capabilities.7:190 build/C/man7/capabilities.7:192 build/C/man7/capabilities.7:194 build/C/man7/capabilities.7:196 build/C/man7/capabilities.7:198 build/C/man7/capabilities.7:200 build/C/man7/capabilities.7:202 build/C/man7/capabilities.7:204 build/C/man7/capabilities.7:206 build/C/man7/capabilities.7:230 build/C/man7/capabilities.7:232 build/C/man7/capabilities.7:278 build/C/man7/capabilities.7:288 build/C/man7/capabilities.7:294 build/C/man7/capabilities.7:299 build/C/man7/capabilities.7:305 build/C/man7/capabilities.7:312 build/C/man7/capabilities.7:315 build/C/man7/capabilities.7:323 build/C/man7/capabilities.7:325 build/C/man7/capabilities.7:334 build/C/man7/capabilities.7:341 build/C/man7/capabilities.7:344 build/C/man7/capabilities.7:348 build/C/man7/capabilities.7:351 build/C/man7/capabilities.7:354 build/C/man7/capabilities.7:361 build/C/man7/capabilities.7:366 build/C/man7/capabilities.7:372 build/C/man7/capabilities.7:376 build/C/man7/capabilities.7:380 build/C/man7/capabilities.7:384 build/C/man7/capabilities.7:388 build/C/man7/capabilities.7:415 build/C/man7/capabilities.7:420 build/C/man7/capabilities.7:425 build/C/man7/capabilities.7:428 build/C/man7/capabilities.7:431 build/C/man7/capabilities.7:440 build/C/man7/capabilities.7:444 build/C/man7/capabilities.7:470 build/C/man7/capabilities.7:475 build/C/man7/capabilities.7:478 build/C/man7/capabilities.7:483 build/C/man7/capabilities.7:486 build/C/man7/capabilities.7:489 build/C/man7/capabilities.7:492 build/C/man7/capabilities.7:495 build/C/man7/capabilities.7:500 build/C/man7/capabilities.7:502 build/C/man7/capabilities.7:508 build/C/man7/capabilities.7:516 build/C/man7/capabilities.7:518 build/C/man7/capabilities.7:522 build/C/man7/capabilities.7:524 build/C/man7/capabilities.7:527 build/C/man7/capabilities.7:531 build/C/man7/capabilities.7:533 build/C/man7/capabilities.7:535 build/C/man7/capabilities.7:537 build/C/man7/capabilities.7:546 build/C/man7/capabilities.7:553 build/C/man7/capabilities.7:558 build/C/man7/capabilities.7:563 build/C/man7/capabilities.7:590 build/C/man7/capabilities.7:597 build/C/man7/capabilities.7:788 build/C/man7/capabilities.7:796 build/C/man7/capabilities.7:1112 build/C/man7/capabilities.7:1117 build/C/man7/cpuset.7:540 build/C/man7/cpuset.7:545 build/C/man7/cpuset.7:550 build/C/man7/cpuset.7:726 build/C/man7/cpuset.7:730 build/C/man7/cpuset.7:927 build/C/man7/cpuset.7:930 build/C/man7/cpuset.7:934 build/C/man7/cpuset.7:938 build/C/man7/cpuset.7:942 build/C/man7/credentials.7:125 build/C/man7/credentials.7:131 build/C/man7/credentials.7:143 build/C/man7/credentials.7:165 build/C/man7/credentials.7:182 build/C/man7/credentials.7:214 build/C/man7/credentials.7:217 build/C/man7/credentials.7:227 build/C/man7/credentials.7:230
684 #: build/C/man7/capabilities.7:112
686 "Bypass permission checks on operations that normally require the file system "
687 "UID of the process to match the UID of the file (e.g., B<chmod>(2), "
688 "B<utime>(2)), excluding those operations covered by B<CAP_DAC_OVERRIDE> and "
689 "B<CAP_DAC_READ_SEARCH>;"
693 #: build/C/man7/capabilities.7:116
694 msgid "set extended file attributes (see B<chattr>(1)) on arbitrary files;"
698 #: build/C/man7/capabilities.7:118
699 msgid "set Access Control Lists (ACLs) on arbitrary files;"
703 #: build/C/man7/capabilities.7:120
704 msgid "ignore directory sticky bit on file deletion;"
708 #: build/C/man7/capabilities.7:127
709 msgid "specify B<O_NOATIME> for arbitrary files in B<open>(2) and B<fcntl>(2)."
713 #: build/C/man7/capabilities.7:129
715 msgid "B<CAP_FSETID>"
719 #: build/C/man7/capabilities.7:135
721 "Don't clear set-user-ID and set-group-ID permission bits when a file is "
722 "modified; set the set-group-ID bit for a file whose GID does not match the "
723 "file system or any of the supplementary GIDs of the calling process."
727 #: build/C/man7/capabilities.7:135
729 msgid "B<CAP_IPC_LOCK>"
732 #. FIXME As at Linux 3.2, there are some strange uses of this capability
733 #. in other places; they probably should be replaced with something else.
735 #: build/C/man7/capabilities.7:144
736 msgid "Lock memory (B<mlock>(2), B<mlockall>(2), B<mmap>(2), B<shmctl>(2))."
740 #: build/C/man7/capabilities.7:144
742 msgid "B<CAP_IPC_OWNER>"
746 #: build/C/man7/capabilities.7:147
747 msgid "Bypass permission checks for operations on System V IPC objects."
751 #: build/C/man7/capabilities.7:147
756 #. FIXME CAP_KILL also has an effect for threads + setting child
757 #. termination signal to other than SIGCHLD: without this
758 #. capability, the termination signal reverts to SIGCHLD
759 #. if the child does an exec(). What is the rationale
762 #: build/C/man7/capabilities.7:160
764 "Bypass permission checks for sending signals (see B<kill>(2)). This "
765 "includes use of the B<ioctl>(2) B<KDSIGACCEPT> operation."
769 #: build/C/man7/capabilities.7:160
771 msgid "B<CAP_LEASE> (since Linux 2.4)"
775 #: build/C/man7/capabilities.7:164
776 msgid "Establish leases on arbitrary files (see B<fcntl>(2))."
780 #: build/C/man7/capabilities.7:164
782 msgid "B<CAP_LINUX_IMMUTABLE>"
785 #. These attributes are now available on ext2, ext3, Reiserfs, XFS, JFS
787 #: build/C/man7/capabilities.7:173
789 "Set the B<FS_APPEND_FL> and B<FS_IMMUTABLE_FL> i-node flags (see "
794 #: build/C/man7/capabilities.7:173
796 msgid "B<CAP_MAC_ADMIN> (since Linux 2.6.25)"
800 #: build/C/man7/capabilities.7:177
802 "Override Mandatory Access Control (MAC). Implemented for the Smack Linux "
803 "Security Module (LSM)."
807 #: build/C/man7/capabilities.7:177
809 msgid "B<CAP_MAC_OVERRIDE> (since Linux 2.6.25)"
813 #: build/C/man7/capabilities.7:181
814 msgid "Allow MAC configuration or state changes. Implemented for the Smack LSM."
818 #: build/C/man7/capabilities.7:181
820 msgid "B<CAP_MKNOD> (since Linux 2.4)"
824 #: build/C/man7/capabilities.7:185
825 msgid "Create special files using B<mknod>(2)."
829 #: build/C/man7/capabilities.7:185
831 msgid "B<CAP_NET_ADMIN>"
835 #: build/C/man7/capabilities.7:188
836 msgid "Perform various network-related operations:"
840 #: build/C/man7/capabilities.7:192
841 msgid "interface configuration;"
845 #: build/C/man7/capabilities.7:194
846 msgid "administration of IP firewall, masquerading, and accounting"
850 #: build/C/man7/capabilities.7:196
851 msgid "modify routing tables;"
855 #: build/C/man7/capabilities.7:198
856 msgid "bind to any address for transparent proxying;"
860 #: build/C/man7/capabilities.7:200
861 msgid "set type-of-service (TOS)"
865 #: build/C/man7/capabilities.7:202
866 msgid "clear driver statistics;"
870 #: build/C/man7/capabilities.7:204
871 msgid "set promiscuous mode;"
875 #: build/C/man7/capabilities.7:206
876 msgid "enabling multicasting;"
880 #: build/C/man7/capabilities.7:217
882 "use B<setsockopt>(2) to set the following socket options: B<SO_DEBUG>, "
883 "B<SO_MARK>, B<SO_PRIORITY> (for a priority outside the range 0 to 6), "
884 "B<SO_RCVBUFFORCE>, and B<SO_SNDBUFFORCE>."
888 #: build/C/man7/capabilities.7:219
890 msgid "B<CAP_NET_BIND_SERVICE>"
894 #: build/C/man7/capabilities.7:223
896 "Bind a socket to Internet domain privileged ports (port numbers less than "
901 #: build/C/man7/capabilities.7:223
903 msgid "B<CAP_NET_BROADCAST>"
907 #: build/C/man7/capabilities.7:226
908 msgid "(Unused) Make socket broadcasts, and listen to multicasts."
912 #: build/C/man7/capabilities.7:226
914 msgid "B<CAP_NET_RAW>"
918 #: build/C/man7/capabilities.7:232
919 msgid "use RAW and PACKET sockets;"
923 #: build/C/man7/capabilities.7:234
924 msgid "bind to any address for transparent proxying."
928 #: build/C/man7/capabilities.7:237
930 msgid "B<CAP_SETGID>"
934 #: build/C/man7/capabilities.7:241
936 "Make arbitrary manipulations of process GIDs and supplementary GID list; "
937 "forge GID when passing socket credentials via UNIX domain sockets."
941 #: build/C/man7/capabilities.7:241
943 msgid "B<CAP_SETFCAP> (since Linux 2.6.24)"
947 #: build/C/man7/capabilities.7:244
948 msgid "Set file capabilities."
952 #: build/C/man7/capabilities.7:244
954 msgid "B<CAP_SETPCAP>"
958 #: build/C/man7/capabilities.7:255
960 "If file capabilities are not supported: grant or remove any capability in "
961 "the caller's permitted capability set to or from any other process. (This "
962 "property of B<CAP_SETPCAP> is not available when the kernel is configured to "
963 "support file capabilities, since B<CAP_SETPCAP> has entirely different "
964 "semantics for such kernels.)"
968 #: build/C/man7/capabilities.7:265
970 "If file capabilities are supported: add any capability from the calling "
971 "thread's bounding set to its inheritable set; drop capabilities from the "
972 "bounding set (via B<prctl>(2) B<PR_CAPBSET_DROP>); make changes to the "
973 "I<securebits> flags."
977 #: build/C/man7/capabilities.7:265
979 msgid "B<CAP_SETUID>"
982 #. FIXME CAP_SETUID also an effect in exec(); document this.
984 #: build/C/man7/capabilities.7:274
986 "Make arbitrary manipulations of process UIDs (B<setuid>(2), B<setreuid>(2), "
987 "B<setresuid>(2), B<setfsuid>(2)); make forged UID when passing socket "
988 "credentials via UNIX domain sockets."
992 #: build/C/man7/capabilities.7:274
994 msgid "B<CAP_SYS_ADMIN>"
998 #: build/C/man7/capabilities.7:288
1000 "Perform a range of system administration operations including: "
1001 "B<quotactl>(2), B<mount>(2), B<umount>(2), B<swapon>(2), B<swapoff>(2), "
1002 "B<sethostname>(2), and B<setdomainname>(2);"
1006 #: build/C/man7/capabilities.7:294
1008 "perform privileged B<syslog>(2) operations (since Linux 2.6.37, "
1009 "B<CAP_SYSLOG> should be used to permit such operations);"
1013 #: build/C/man7/capabilities.7:299
1014 msgid "perform B<VM86_REQUEST_IRQ> B<vm86>(2) command;"
1018 #: build/C/man7/capabilities.7:305
1020 "perform B<IPC_SET> and B<IPC_RMID> operations on arbitrary System V IPC "
1025 #: build/C/man7/capabilities.7:312
1027 "perform operations on I<trusted> and I<security> Extended Attributes (see "
1032 #: build/C/man7/capabilities.7:315
1033 msgid "use B<lookup_dcookie>(2);"
1037 #: build/C/man7/capabilities.7:323
1039 "use B<ioprio_set>(2) to assign B<IOPRIO_CLASS_RT> and (before Linux 2.6.25) "
1040 "B<IOPRIO_CLASS_IDLE> I/O scheduling classes;"
1044 #: build/C/man7/capabilities.7:325
1045 msgid "forge UID when passing socket credentials;"
1049 #: build/C/man7/capabilities.7:334
1051 "exceed I</proc/sys/fs/file-max>, the system-wide limit on the number of open "
1052 "files, in system calls that open files (e.g., B<accept>(2), B<execve>(2), "
1053 "B<open>(2), B<pipe>(2));"
1057 #: build/C/man7/capabilities.7:341
1059 "employ B<CLONE_*> flags that create new namespaces with B<clone>(2) and "
1064 #: build/C/man7/capabilities.7:344
1065 msgid "call B<perf_event_open>(2);"
1069 #: build/C/man7/capabilities.7:348
1070 msgid "access privileged I<perf> event information;"
1074 #: build/C/man7/capabilities.7:351
1075 msgid "call B<setns>(2);"
1079 #: build/C/man7/capabilities.7:354
1080 msgid "call B<fanotify_init>(2);"
1084 #: build/C/man7/capabilities.7:361
1085 msgid "perform B<KEYCTL_CHOWN> and B<KEYCTL_SETPERM> B<keyctl>(2) operations;"
1089 #: build/C/man7/capabilities.7:366
1090 msgid "perform B<madvise>(2) B<MADV_HWPOISON> operation;"
1094 #: build/C/man7/capabilities.7:372
1096 "employ the B<TIOCSTI> B<ioctl>(2) to insert characters into the input queue "
1097 "of a terminal other than the caller's controlling terminal."
1101 #: build/C/man7/capabilities.7:376
1102 msgid "employ the obsolete B<nfsservctl>(2) system call;"
1106 #: build/C/man7/capabilities.7:380
1107 msgid "employ the obsolete B<bdflush>(2) system call;"
1111 #: build/C/man7/capabilities.7:384
1112 msgid "perform various privileged block-device B<ioctl>(2) operations;"
1116 #: build/C/man7/capabilities.7:388
1117 msgid "perform various privileged file-system B<ioctl>(2) operations;"
1121 #: build/C/man7/capabilities.7:390
1122 msgid "perform administrative operations on many device drivers."
1126 #: build/C/man7/capabilities.7:392
1128 msgid "B<CAP_SYS_BOOT>"
1132 #: build/C/man7/capabilities.7:398
1133 msgid "Use B<reboot>(2) and B<kexec_load>(2)."
1137 #: build/C/man7/capabilities.7:398
1139 msgid "B<CAP_SYS_CHROOT>"
1143 #: build/C/man7/capabilities.7:402
1144 msgid "Use B<chroot>(2)."
1148 #: build/C/man7/capabilities.7:402
1150 msgid "B<CAP_SYS_MODULE>"
1154 #: build/C/man7/capabilities.7:411
1156 "Load and unload kernel modules (see B<init_module>(2) and "
1157 "B<delete_module>(2)); in kernels before 2.6.25: drop capabilities from the "
1158 "system-wide capability bounding set."
1162 #: build/C/man7/capabilities.7:411
1164 msgid "B<CAP_SYS_NICE>"
1168 #: build/C/man7/capabilities.7:420
1170 "Raise process nice value (B<nice>(2), B<setpriority>(2)) and change the "
1171 "nice value for arbitrary processes;"
1175 #: build/C/man7/capabilities.7:425
1177 "set real-time scheduling policies for calling process, and set scheduling "
1178 "policies and priorities for arbitrary processes (B<sched_setscheduler>(2), "
1179 "B<sched_setparam>(2));"
1183 #: build/C/man7/capabilities.7:428
1184 msgid "set CPU affinity for arbitrary processes (B<sched_setaffinity>(2));"
1188 #: build/C/man7/capabilities.7:431
1190 "set I/O scheduling class and priority for arbitrary processes "
1191 "(B<ioprio_set>(2));"
1194 #. FIXME CAP_SYS_NICE also has the following effect for
1195 #. migrate_pages(2):
1196 #. do_migrate_pages(mm, &old, &new,
1197 #. capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
1199 #: build/C/man7/capabilities.7:440
1201 "apply B<migrate_pages>(2) to arbitrary processes and allow processes to be "
1202 "migrated to arbitrary nodes;"
1206 #: build/C/man7/capabilities.7:444
1207 msgid "apply B<move_pages>(2) to arbitrary processes;"
1211 #: build/C/man7/capabilities.7:451
1212 msgid "use the B<MPOL_MF_MOVE_ALL> flag with B<mbind>(2) and B<move_pages>(2)."
1216 #: build/C/man7/capabilities.7:453
1218 msgid "B<CAP_SYS_PACCT>"
1222 #: build/C/man7/capabilities.7:457
1223 msgid "Use B<acct>(2)."
1227 #: build/C/man7/capabilities.7:457
1229 msgid "B<CAP_SYS_PTRACE>"
1233 #: build/C/man7/capabilities.7:466
1235 "Trace arbitrary processes using B<ptrace>(2); apply B<get_robust_list>(2) "
1236 "to arbitrary processes; inspect processes using B<kcmp>(2)."
1240 #: build/C/man7/capabilities.7:466
1242 msgid "B<CAP_SYS_RAWIO>"
1246 #: build/C/man7/capabilities.7:475
1247 msgid "Perform I/O port operations (B<iopl>(2) and B<ioperm>(2));"
1251 #: build/C/man7/capabilities.7:478
1252 msgid "access I</proc/kcore>;"
1256 #: build/C/man7/capabilities.7:483
1257 msgid "employ the B<FIBMAP> B<ioctl>(2) operation;"
1261 #: build/C/man7/capabilities.7:486
1263 "open devices for accessing x86 model-specific registers (MSRs, see "
1268 #: build/C/man7/capabilities.7:489
1269 msgid "update I</proc/sys/vm/mmap_min_addr>;"
1273 #: build/C/man7/capabilities.7:492
1275 "create memory mappings at addresses below the value specified by "
1276 "I</proc/sys/vm/mmap_min_addr>;"
1280 #: build/C/man7/capabilities.7:495
1281 msgid "map files in I</proc/pci/bus>;"
1285 #: build/C/man7/capabilities.7:500
1286 msgid "open I</dev/mem> and I</dev/kmem>;"
1290 #: build/C/man7/capabilities.7:502
1291 msgid "perform various SCSI device commands;"
1295 #: build/C/man7/capabilities.7:508
1296 msgid "perform certain operations on B<hpsa>(4) and B<cciss>(4) devices;"
1300 #: build/C/man7/capabilities.7:510
1301 msgid "perform a range of device-specific operations on other devices."
1305 #: build/C/man7/capabilities.7:512
1307 msgid "B<CAP_SYS_RESOURCE>"
1311 #: build/C/man7/capabilities.7:518
1312 msgid "Use reserved space on ext2 file systems;"
1316 #: build/C/man7/capabilities.7:522
1317 msgid "make B<ioctl>(2) calls controlling ext3 journaling;"
1321 #: build/C/man7/capabilities.7:524
1322 msgid "override disk quota limits;"
1326 #: build/C/man7/capabilities.7:527
1327 msgid "increase resource limits (see B<setrlimit>(2));"
1331 #: build/C/man7/capabilities.7:531
1332 msgid "override B<RLIMIT_NPROC> resource limit;"
1336 #: build/C/man7/capabilities.7:533
1337 msgid "override maximum number of consoles on console allocation;"
1341 #: build/C/man7/capabilities.7:535
1342 msgid "override maximum number of keymaps;"
1346 #: build/C/man7/capabilities.7:537
1347 msgid "allow more than 64hz interrupts from the real-time clock;"
1351 #: build/C/man7/capabilities.7:546
1353 "raise I<msg_qbytes> limit for a System V message queue above the limit in "
1354 "I</proc/sys/kernel/msgmnb> (see B<msgop>(2) and B<msgctl>(2));"
1358 #: build/C/man7/capabilities.7:553
1360 "override the I</proc/sys/fs/pipe-size-max> limit when setting the capacity "
1361 "of a pipe using the B<F_SETPIPE_SZ> B<fcntl>(2) command."
1365 #: build/C/man7/capabilities.7:558
1367 "use B<F_SETPIPE_SZ> to increase the capacity of a pipe above the limit "
1368 "specified by I</proc/sys/fs/pipe-max-size>;"
1372 #: build/C/man7/capabilities.7:563
1374 "override I</proc/sys/fs/mqueue/queues_max> limit when creating POSIX message "
1375 "queues (see B<mq_overview>(7));"
1379 #: build/C/man7/capabilities.7:572
1381 "employ B<prctl>(2) B<PR_SET_MM> operation; set I</proc/PID/oom_score_adj> "
1382 "to a value lower than the value last set by a process with "
1383 "B<CAP_SYS_RESOURCE>."
1387 #: build/C/man7/capabilities.7:574
1389 msgid "B<CAP_SYS_TIME>"
1393 #: build/C/man7/capabilities.7:581
1395 "Set system clock (B<settimeofday>(2), B<stime>(2), B<adjtimex>(2)); set "
1396 "real-time (hardware) clock."
1400 #: build/C/man7/capabilities.7:581
1402 msgid "B<CAP_SYS_TTY_CONFIG>"
1406 #: build/C/man7/capabilities.7:588
1408 "Use B<vhangup>(2); employ various privileged B<ioctl>(2) operations on "
1409 "virtual terminals."
1413 #: build/C/man7/capabilities.7:588
1415 msgid "B<CAP_SYSLOG> (since Linux 2.6.37)"
1419 #: build/C/man7/capabilities.7:597
1421 "Perform privileged B<syslog>(2) operations. See B<syslog>(2) for "
1422 "information on which operations require privilege."
1426 #: build/C/man7/capabilities.7:607
1428 "View kernel addresses exposed via I</proc> and other interfaces when "
1429 "I</proc/sys/kernel/kptr_restrict> has the value 1. (See the discussion of "
1430 "the I<kptr_restrict> in B<proc>(5).)"
1434 #: build/C/man7/capabilities.7:607
1436 msgid "B<CAP_WAKE_ALARM> (since Linux 3.0)"
1440 #: build/C/man7/capabilities.7:615
1442 "Trigger something that will wake up the system (set B<CLOCK_REALTIME_ALARM> "
1443 "and B<CLOCK_BOOTTIME_ALARM> timers)."
1447 #: build/C/man7/capabilities.7:615
1449 msgid "Past and current implementation"
1453 #: build/C/man7/capabilities.7:617
1454 msgid "A full implementation of capabilities requires that:"
1458 #: build/C/man7/capabilities.7:617 build/C/man7/capabilities.7:760 build/C/man7/capabilities.7:907 build/C/man7/capabilities.7:960
1464 #: build/C/man7/capabilities.7:621
1466 "For all privileged operations, the kernel must check whether the thread has "
1467 "the required capability in its effective set."
1471 #: build/C/man7/capabilities.7:621 build/C/man7/capabilities.7:765 build/C/man7/capabilities.7:913 build/C/man7/capabilities.7:966
1477 #: build/C/man7/capabilities.7:624
1479 "The kernel must provide system calls allowing a thread's capability sets to "
1480 "be changed and retrieved."
1484 #: build/C/man7/capabilities.7:624 build/C/man7/capabilities.7:916 build/C/man7/capabilities.7:970
1490 #: build/C/man7/capabilities.7:627
1492 "The file system must support attaching capabilities to an executable file, "
1493 "so that a process gains those capabilities when the file is executed."
1497 #: build/C/man7/capabilities.7:631
1499 "Before kernel 2.6.24, only the first two of these requirements are met; "
1500 "since kernel 2.6.24, all three requirements are met."
1504 #: build/C/man7/capabilities.7:631
1506 msgid "Thread capability sets"
1510 #: build/C/man7/capabilities.7:634
1512 "Each thread has three capability sets containing zero or more of the above "
1517 #: build/C/man7/capabilities.7:634
1519 msgid "I<Permitted>:"
1523 #: build/C/man7/capabilities.7:642
1525 "This is a limiting superset for the effective capabilities that the thread "
1526 "may assume. It is also a limiting superset for the capabilities that may be "
1527 "added to the inheritable set by a thread that does not have the "
1528 "B<CAP_SETPCAP> capability in its effective set."
1532 #: build/C/man7/capabilities.7:648
1534 "If a thread drops a capability from its permitted set, it can never "
1535 "reacquire that capability (unless it B<execve>(2)s either a set-user-ID-root "
1536 "program, or a program whose associated file capabilities grant that "
1541 #: build/C/man7/capabilities.7:648
1543 msgid "I<Inheritable>:"
1547 #: build/C/man7/capabilities.7:655
1549 "This is a set of capabilities preserved across an B<execve>(2). It provides "
1550 "a mechanism for a process to assign capabilities to the permitted set of the "
1551 "new program during an B<execve>(2)."
1555 #: build/C/man7/capabilities.7:655 build/C/man7/capabilities.7:697
1557 msgid "I<Effective>:"
1561 #: build/C/man7/capabilities.7:659
1563 "This is the set of capabilities used by the kernel to perform permission "
1564 "checks for the thread."
1568 #: build/C/man7/capabilities.7:665
1570 "A child created via B<fork>(2) inherits copies of its parent's capability "
1571 "sets. See below for a discussion of the treatment of capabilities during "
1576 #: build/C/man7/capabilities.7:670
1578 "Using B<capset>(2), a thread may manipulate its own capability sets (see "
1583 #: build/C/man7/capabilities.7:670
1585 msgid "File capabilities"
1589 #: build/C/man7/capabilities.7:685
1591 "Since kernel 2.6.24, the kernel supports associating capability sets with an "
1592 "executable file using B<setcap>(8). The file capability sets are stored in "
1593 "an extended attribute (see B<setxattr>(2)) named I<security.capability>. "
1594 "Writing to this extended attribute requires the B<CAP_SETFCAP> capability. "
1595 "The file capability sets, in conjunction with the capability sets of the "
1596 "thread, determine the capabilities of a thread after an B<execve>(2)."
1600 #: build/C/man7/capabilities.7:687
1601 msgid "The three file capability sets are:"
1605 #: build/C/man7/capabilities.7:687
1607 msgid "I<Permitted> (formerly known as I<forced>):"
1611 #: build/C/man7/capabilities.7:691
1613 "These capabilities are automatically permitted to the thread, regardless of "
1614 "the thread's inheritable capabilities."
1618 #: build/C/man7/capabilities.7:691
1620 msgid "I<Inheritable> (formerly known as I<allowed>):"
1624 #: build/C/man7/capabilities.7:697
1626 "This set is ANDed with the thread's inheritable set to determine which "
1627 "inheritable capabilities are enabled in the permitted set of the thread "
1628 "after the B<execve>(2)."
1632 #: build/C/man7/capabilities.7:707
1634 "This is not a set, but rather just a single bit. If this bit is set, then "
1635 "during an B<execve>(2) all of the new permitted capabilities for the thread "
1636 "are also raised in the effective set. If this bit is not set, then after an "
1637 "B<execve>(2), none of the new permitted capabilities is in the new effective "
1642 #: build/C/man7/capabilities.7:723
1644 "Enabling the file effective capability bit implies that any file permitted "
1645 "or inheritable capability that causes a thread to acquire the corresponding "
1646 "permitted capability during an B<execve>(2) (see the transformation rules "
1647 "described below) will also acquire that capability in its effective set. "
1648 "Therefore, when assigning capabilities to a file (B<setcap>(8), "
1649 "B<cap_set_file>(3), B<cap_set_fd>(3)), if we specify the effective flag as "
1650 "being enabled for any capability, then the effective flag must also be "
1651 "specified as enabled for all other capabilities for which the corresponding "
1652 "permitted or inheritable flags is enabled."
1656 #: build/C/man7/capabilities.7:723
1658 msgid "Transformation of capabilities during execve()"
1662 #: build/C/man7/capabilities.7:729
1664 "During an B<execve>(2), the kernel calculates the new capabilities of the "
1665 "process using the following algorithm:"
1669 #: build/C/man7/capabilities.7:734
1672 "P'(permitted) = (P(inheritable) & F(inheritable)) |\n"
1673 " (F(permitted) & cap_bset)\n"
1677 #: build/C/man7/capabilities.7:736
1679 msgid "P'(effective) = F(effective) ? P'(permitted) : 0\n"
1683 #: build/C/man7/capabilities.7:738
1685 msgid "P'(inheritable) = P(inheritable) [i.e., unchanged]\n"
1689 #: build/C/man7/capabilities.7:742
1694 #: build/C/man7/capabilities.7:743
1700 #: build/C/man7/capabilities.7:746
1701 msgid "denotes the value of a thread capability set before the B<execve>(2)"
1705 #: build/C/man7/capabilities.7:746
1711 #: build/C/man7/capabilities.7:749
1712 msgid "denotes the value of a capability set after the B<execve>(2)"
1716 #: build/C/man7/capabilities.7:749
1722 #: build/C/man7/capabilities.7:751
1723 msgid "denotes a file capability set"
1727 #: build/C/man7/capabilities.7:751
1733 #: build/C/man7/capabilities.7:753
1734 msgid "is the value of the capability bounding set (described below)."
1738 #: build/C/man7/capabilities.7:755
1740 msgid "Capabilities and execution of programs by root"
1744 #: build/C/man7/capabilities.7:760
1746 "In order to provide an all-powerful I<root> using capability sets, during an "
1751 #: build/C/man7/capabilities.7:765
1753 "If a set-user-ID-root program is being executed, or the real user ID of the "
1754 "process is 0 (root) then the file inheritable and permitted sets are "
1755 "defined to be all ones (i.e., all capabilities enabled)."
1759 #: build/C/man7/capabilities.7:768
1761 "If a set-user-ID-root program is being executed, then the file effective bit "
1762 "is defined to be one (enabled)."
1765 #. If a process with real UID 0, and nonzero effective UID does an
1766 #. exec(), then it gets all capabilities in its
1767 #. permitted set, and no effective capabilities
1769 #: build/C/man7/capabilities.7:783
1771 "The upshot of the above rules, combined with the capabilities "
1772 "transformations described above, is that when a process B<execve>(2)s a "
1773 "set-user-ID-root program, or when a process with an effective UID of 0 "
1774 "B<execve>(2)s a program, it gains all capabilities in its permitted and "
1775 "effective capability sets, except those masked out by the capability "
1776 "bounding set. This provides semantics that are the same as those provided "
1777 "by traditional UNIX systems."
1781 #: build/C/man7/capabilities.7:783
1783 msgid "Capability bounding set"
1787 #: build/C/man7/capabilities.7:788
1789 "The capability bounding set is a security mechanism that can be used to "
1790 "limit the capabilities that can be gained during an B<execve>(2). The "
1791 "bounding set is used in the following ways:"
1795 #: build/C/man7/capabilities.7:796
1797 "During an B<execve>(2), the capability bounding set is ANDed with the file "
1798 "permitted capability set, and the result of this operation is assigned to "
1799 "the thread's permitted capability set. The capability bounding set thus "
1800 "places a limit on the permitted capabilities that may be granted by an "
1805 #: build/C/man7/capabilities.7:808
1807 "(Since Linux 2.6.25) The capability bounding set acts as a limiting "
1808 "superset for the capabilities that a thread can add to its inheritable set "
1809 "using B<capset>(2). This means that if a capability is not in the bounding "
1810 "set, then a thread can't add this capability to its inheritable set, even if "
1811 "it was in its permitted capabilities, and thereby cannot have this "
1812 "capability preserved in its permitted set when it B<execve>(2)s a file that "
1813 "has the capability in its inheritable set."
1817 #: build/C/man7/capabilities.7:815
1819 "Note that the bounding set masks the file permitted capabilities, but not "
1820 "the inherited capabilities. If a thread maintains a capability in its "
1821 "inherited set that is not in its bounding set, then it can still gain that "
1822 "capability in its permitted set by executing a file that has the capability "
1823 "in its inherited set."
1827 #: build/C/man7/capabilities.7:818
1829 "Depending on the kernel version, the capability bounding set is either a "
1830 "system-wide attribute, or a per-process attribute."
1834 #: build/C/man7/capabilities.7:820
1835 msgid "B<Capability bounding set prior to Linux 2.6.25>"
1839 #: build/C/man7/capabilities.7:828
1841 "In kernels before 2.6.25, the capability bounding set is a system-wide "
1842 "attribute that affects all threads on the system. The bounding set is "
1843 "accessible via the file I</proc/sys/kernel/cap-bound>. (Confusingly, this "
1844 "bit mask parameter is expressed as a signed decimal number in "
1845 "I</proc/sys/kernel/cap-bound>.)"
1849 #: build/C/man7/capabilities.7:835
1851 "Only the B<init> process may set capabilities in the capability bounding "
1852 "set; other than that, the superuser (more precisely: programs with the "
1853 "B<CAP_SYS_MODULE> capability) may only clear capabilities from this set."
1857 #: build/C/man7/capabilities.7:844
1859 "On a standard system the capability bounding set always masks out the "
1860 "B<CAP_SETPCAP> capability. To remove this restriction (dangerous!), modify "
1861 "the definition of B<CAP_INIT_EFF_SET> in I<include/linux/capability.h> and "
1862 "rebuild the kernel."
1866 #: build/C/man7/capabilities.7:848
1868 "The system-wide capability bounding set feature was added to Linux starting "
1869 "with kernel version 2.2.11."
1873 #: build/C/man7/capabilities.7:850
1874 msgid "B<Capability bounding set from Linux 2.6.25 onward>"
1878 #: build/C/man7/capabilities.7:855
1880 "From Linux 2.6.25, the I<capability bounding set> is a per-thread "
1881 "attribute. (There is no longer a system-wide capability bounding set.)"
1885 #: build/C/man7/capabilities.7:860
1887 "The bounding set is inherited at B<fork>(2) from the thread's parent, and "
1888 "is preserved across an B<execve>(2)."
1892 #: build/C/man7/capabilities.7:873
1894 "A thread may remove capabilities from its capability bounding set using the "
1895 "B<prctl>(2) B<PR_CAPBSET_DROP> operation, provided it has the "
1896 "B<CAP_SETPCAP> capability. Once a capability has been dropped from the "
1897 "bounding set, it cannot be restored to that set. A thread can determine if "
1898 "a capability is in its bounding set using the B<prctl>(2) "
1899 "B<PR_CAPBSET_READ> operation."
1903 #: build/C/man7/capabilities.7:891
1905 "Removing capabilities from the bounding set is only supported if file "
1906 "capabilities are compiled into the kernel. In kernels before Linux 2.6.33, "
1907 "file capabilities were an optional feature configurable via the "
1908 "CONFIG_SECURITY_FILE_CAPABILITIES option. Since Linux 2.6.33, the "
1909 "configuration option has been removed and file capabilities are always part "
1910 "of the kernel. When file capabilities are compiled into the kernel, the "
1911 "B<init> process (the ancestor of all processes) begins with a full bounding "
1912 "set. If file capabilities are not compiled into the kernel, then B<init> "
1913 "begins with a full bounding set minus B<CAP_SETPCAP>, because this "
1914 "capability has a different meaning when there are no file capabilities."
1918 #: build/C/man7/capabilities.7:898
1920 "Removing a capability from the bounding set does not remove it from the "
1921 "thread's inherited set. However it does prevent the capability from being "
1922 "added back into the thread's inherited set in the future."
1926 #: build/C/man7/capabilities.7:898
1928 msgid "Effect of user ID changes on capabilities"
1932 #: build/C/man7/capabilities.7:907
1934 "To preserve the traditional semantics for transitions between 0 and nonzero "
1935 "user IDs, the kernel makes the following changes to a thread's capability "
1936 "sets on changes to the thread's real, effective, saved set, and file system "
1937 "user IDs (using B<setuid>(2), B<setresuid>(2), or similar):"
1941 #: build/C/man7/capabilities.7:913
1943 "If one or more of the real, effective or saved set user IDs was previously "
1944 "0, and as a result of the UID changes all of these IDs have a nonzero value, "
1945 "then all capabilities are cleared from the permitted and effective "
1950 #: build/C/man7/capabilities.7:916
1952 "If the effective user ID is changed from 0 to nonzero, then all capabilities "
1953 "are cleared from the effective set."
1957 #: build/C/man7/capabilities.7:919
1959 "If the effective user ID is changed from nonzero to 0, then the permitted "
1960 "set is copied to the effective set."
1964 #: build/C/man7/capabilities.7:919 build/C/man7/capabilities.7:974
1970 #: build/C/man7/capabilities.7:937
1972 "If the file system user ID is changed from 0 to nonzero (see B<setfsuid>(2)) "
1973 "then the following capabilities are cleared from the effective set: "
1974 "B<CAP_CHOWN>, B<CAP_DAC_OVERRIDE>, B<CAP_DAC_READ_SEARCH>, B<CAP_FOWNER>, "
1975 "B<CAP_FSETID>, B<CAP_LINUX_IMMUTABLE> (since Linux 2.2.30), "
1976 "B<CAP_MAC_OVERRIDE>, and B<CAP_MKNOD> (since Linux 2.2.30). If the file "
1977 "system UID is changed from nonzero to 0, then any of these capabilities that "
1978 "are enabled in the permitted set are enabled in the effective set."
1982 #: build/C/man7/capabilities.7:945
1984 "If a thread that has a 0 value for one or more of its user IDs wants to "
1985 "prevent its permitted capability set being cleared when it resets all of its "
1986 "user IDs to nonzero values, it can do so using the B<prctl>(2) "
1987 "B<PR_SET_KEEPCAPS> operation."
1991 #: build/C/man7/capabilities.7:945
1993 msgid "Programmatically adjusting capability sets"
1997 #: build/C/man7/capabilities.7:960
1999 "A thread can retrieve and change its capability sets using the B<capget>(2) "
2000 "and B<capset>(2) system calls. However, the use of B<cap_get_proc>(3) and "
2001 "B<cap_set_proc>(3), both provided in the I<libcap> package, is preferred for "
2002 "this purpose. The following rules govern changes to the thread capability "
2007 #: build/C/man7/capabilities.7:966
2009 "If the caller does not have the B<CAP_SETPCAP> capability, the new "
2010 "inheritable set must be a subset of the combination of the existing "
2011 "inheritable and permitted sets."
2015 #: build/C/man7/capabilities.7:970
2017 "(Since kernel 2.6.25) The new inheritable set must be a subset of the "
2018 "combination of the existing inheritable set and the capability bounding set."
2022 #: build/C/man7/capabilities.7:974
2024 "The new permitted set must be a subset of the existing permitted set (i.e., "
2025 "it is not possible to acquire permitted capabilities that the thread does "
2026 "not currently have)."
2030 #: build/C/man7/capabilities.7:976
2031 msgid "The new effective set must be a subset of the new permitted set."
2035 #: build/C/man7/capabilities.7:976
2037 msgid "The securebits flags: establishing a capabilities-only environment"
2040 #. For some background:
2041 #. see http://lwn.net/Articles/280279/ and
2042 #. http://article.gmane.org/gmane.linux.kernel.lsm/5476/
2044 #: build/C/man7/capabilities.7:987
2046 "Starting with kernel 2.6.26, and with a kernel in which file capabilities "
2047 "are enabled, Linux implements a set of per-thread I<securebits> flags that "
2048 "can be used to disable special handling of capabilities for UID 0 "
2049 "(I<root>). These flags are as follows:"
2053 #: build/C/man7/capabilities.7:987
2055 msgid "B<SECBIT_KEEP_CAPS>"
2059 #: build/C/man7/capabilities.7:999
2061 "Setting this flag allows a thread that has one or more 0 UIDs to retain its "
2062 "capabilities when it switches all of its UIDs to a nonzero value. If this "
2063 "flag is not set, then such a UID switch causes the thread to lose all "
2064 "capabilities. This flag is always cleared on an B<execve>(2). (This flag "
2065 "provides the same functionality as the older B<prctl>(2) B<PR_SET_KEEPCAPS> "
2070 #: build/C/man7/capabilities.7:999
2072 msgid "B<SECBIT_NO_SETUID_FIXUP>"
2076 #: build/C/man7/capabilities.7:1006
2078 "Setting this flag stops the kernel from adjusting capability sets when the "
2079 "threads's effective and file system UIDs are switched between zero and "
2080 "nonzero values. (See the subsection I<Effect of User ID Changes on "
2085 #: build/C/man7/capabilities.7:1006
2087 msgid "B<SECBIT_NOROOT>"
2091 #: build/C/man7/capabilities.7:1014
2093 "If this bit is set, then the kernel does not grant capabilities when a "
2094 "set-user-ID-root program is executed, or when a process with an effective or "
2095 "real UID of 0 calls B<execve>(2). (See the subsection I<Capabilities and "
2096 "execution of programs by root>.)"
2100 #: build/C/man7/capabilities.7:1024
2102 "Each of the above \"base\" flags has a companion \"locked\" flag. Setting "
2103 "any of the \"locked\" flags is irreversible, and has the effect of "
2104 "preventing further changes to the corresponding \"base\" flag. The locked "
2105 "flags are: B<SECBIT_KEEP_CAPS_LOCKED>, B<SECBIT_NO_SETUID_FIXUP_LOCKED>, and "
2106 "B<SECBIT_NOROOT_LOCKED>."
2110 #: build/C/man7/capabilities.7:1036
2112 "The I<securebits> flags can be modified and retrieved using the B<prctl>(2) "
2113 "B<PR_SET_SECUREBITS> and B<PR_GET_SECUREBITS> operations. The "
2114 "B<CAP_SETPCAP> capability is required to modify the flags."
2118 #: build/C/man7/capabilities.7:1045
2120 "The I<securebits> flags are inherited by child processes. During an "
2121 "B<execve>(2), all of the flags are preserved, except B<SECBIT_KEEP_CAPS> "
2122 "which is always cleared."
2126 #: build/C/man7/capabilities.7:1050
2128 "An application can use the following call to lock itself, and all of its "
2129 "descendants, into an environment where the only way of gaining capabilities "
2130 "is by executing a program with associated file capabilities:"
2134 #: build/C/man7/capabilities.7:1059
2137 "prctl(PR_SET_SECUREBITS,\n"
2138 " SECBIT_KEEP_CAPS_LOCKED |\n"
2139 " SECBIT_NO_SETUID_FIXUP |\n"
2140 " SECBIT_NO_SETUID_FIXUP_LOCKED |\n"
2141 " SECBIT_NOROOT |\n"
2142 " SECBIT_NOROOT_LOCKED);\n"
2146 #: build/C/man7/capabilities.7:1067
2148 "No standards govern capabilities, but the Linux capability implementation is "
2149 "based on the withdrawn POSIX.1e draft standard; see E<.UR "
2150 "http://wt.tuxomania.net\\:/publications\\:/posix.1e/> E<.UE .>"
2154 #: build/C/man7/capabilities.7:1071
2156 "Since kernel 2.5.27, capabilities are an optional kernel component, and can "
2157 "be enabled/disabled via the CONFIG_SECURITY_CAPABILITIES kernel "
2158 "configuration option."
2161 #. 7b9a7ec565505699f503b4fcf61500dceb36e744
2163 #: build/C/man7/capabilities.7:1085
2165 "The I</proc/PID/task/TID/status> file can be used to view the capability "
2166 "sets of a thread. The I</proc/PID/status> file shows the capability sets of "
2167 "a process's main thread. Before Linux 3.8, nonexistent capabilities were "
2168 "shown as being enabled (1) in these sets. Since Linux 3.8, all non-existent "
2169 "capabilities (above B<CAP_LAST_CAP>) are shown as disabled (0)."
2173 #: build/C/man7/capabilities.7:1100
2175 "The I<libcap> package provides a suite of routines for setting and getting "
2176 "capabilities that is more comfortable and less likely to change than the "
2177 "interface provided by B<capset>(2) and B<capget>(2). This package also "
2178 "provides the B<setcap>(8) and B<getcap>(8) programs. It can be found at"
2182 #: build/C/man7/capabilities.7:1103
2185 "http://www.kernel.org\\:/pub\\:/linux\\:/libs\\:/security\\:/linux-privs> "
2190 #: build/C/man7/capabilities.7:1112
2192 "Before kernel 2.6.24, and since kernel 2.6.24 if file capabilities are not "
2193 "enabled, a thread with the B<CAP_SETPCAP> capability can manipulate the "
2194 "capabilities of threads other than itself. However, this is only "
2195 "theoretically possible, since no thread ever has B<CAP_SETPCAP> in either of "
2200 #: build/C/man7/capabilities.7:1117
2202 "In the pre-2.6.25 implementation the system-wide capability bounding set, "
2203 "I</proc/sys/kernel/cap-bound>, always masks out this capability, and this "
2204 "can not be changed without modifying the kernel source and rebuilding."
2208 #: build/C/man7/capabilities.7:1123
2210 "If file capabilities are disabled in the current implementation, then "
2211 "B<init> starts out with this capability removed from its per-process "
2212 "bounding set, and that bounding set is inherited by all other processes "
2213 "created on the system."
2217 #: build/C/man7/capabilities.7:1140
2219 "B<capget>(2), B<prctl>(2), B<setfsuid>(2), B<cap_clear>(3), "
2220 "B<cap_copy_ext>(3), B<cap_from_text>(3), B<cap_get_file>(3), "
2221 "B<cap_get_proc>(3), B<cap_init>(3), B<capgetp>(3), B<capsetp>(3), "
2222 "B<libcap>(3), B<credentials>(7), B<pthreads>(7), B<getcap>(8), B<setcap>(8)"
2226 #: build/C/man7/capabilities.7:1143
2227 msgid "I<include/linux/capability.h> in the Linux kernel source tree"
2231 #: build/C/man2/capget.2:15
2237 #: build/C/man2/capget.2:18
2238 msgid "capget, capset - set/get capabilities of thread(s)"
2242 #: build/C/man2/capget.2:20
2243 msgid "B<#include E<lt>sys/capability.hE<gt>>"
2247 #: build/C/man2/capget.2:22
2248 msgid "B<int capget(cap_user_header_t >I<hdrp>B<, cap_user_data_t >I<datap>B<);>"
2252 #: build/C/man2/capget.2:24
2254 "B<int capset(cap_user_header_t >I<hdrp>B<, const cap_user_data_t "
2259 #: build/C/man2/capget.2:35
2261 "As of Linux 2.2, the power of the superuser (root) has been partitioned into "
2262 "a set of discrete capabilities. Each thread has a set of effective "
2263 "capabilities identifying which capabilities (if any) it may currently "
2264 "exercise. Each thread also has a set of inheritable capabilities that may "
2265 "be passed through an B<execve>(2) call, and a set of permitted capabilities "
2266 "that it can make effective or inheritable."
2270 #: build/C/man2/capget.2:44
2272 "These two system calls are the raw kernel interface for getting and setting "
2273 "thread capabilities. Not only are these system calls specific to Linux, but "
2274 "the kernel API is likely to change and use of these system calls (in "
2275 "particular the format of the I<cap_user_*_t> types) is subject to extension "
2276 "with each kernel revision, but old programs will keep working."
2280 #: build/C/man2/capget.2:55
2282 "The portable interfaces are B<cap_set_proc>(3) and B<cap_get_proc>(3); if "
2283 "possible you should use those interfaces in applications. If you wish to "
2284 "use the Linux extensions in applications, you should use the easier-to-use "
2285 "interfaces B<capsetp>(3) and B<capgetp>(3)."
2289 #: build/C/man2/capget.2:55
2291 msgid "Current details"
2295 #: build/C/man2/capget.2:58
2297 "Now that you have been warned, some current kernel details. The structures "
2298 "are defined as follows."
2302 #: build/C/man2/capget.2:63
2305 "#define _LINUX_CAPABILITY_VERSION_1 0x19980330\n"
2306 "#define _LINUX_CAPABILITY_U32S_1 1\n"
2310 #: build/C/man2/capget.2:66
2313 "#define _LINUX_CAPABILITY_VERSION_2 0x20071026\n"
2314 "#define _LINUX_CAPABILITY_U32S_2 2\n"
2318 #: build/C/man2/capget.2:71
2321 "typedef struct __user_cap_header_struct {\n"
2324 "} *cap_user_header_t;\n"
2328 #: build/C/man2/capget.2:77
2331 "typedef struct __user_cap_data_struct {\n"
2332 " __u32 effective;\n"
2333 " __u32 permitted;\n"
2334 " __u32 inheritable;\n"
2335 "} *cap_user_data_t;\n"
2339 #: build/C/man2/capget.2:96
2341 "The I<effective>, I<permitted>, and I<inheritable> fields are bit masks of "
2342 "the capabilities defined in I<capability(7).> Note the B<CAP_*> values are "
2343 "bit indexes and need to be bit-shifted before ORing into the bit fields. To "
2344 "define the structures for passing to the system call you have to use the "
2345 "I<struct __user_cap_header_struct> and I<struct __user_cap_data_struct> "
2346 "names because the typedefs are only pointers."
2350 #: build/C/man2/capget.2:108
2352 "Kernels prior to 2.6.25 prefer 32-bit capabilities with version "
2353 "B<_LINUX_CAPABILITY_VERSION_1>, and kernels 2.6.25+ prefer 64-bit "
2354 "capabilities with version B<_LINUX_CAPABILITY_VERSION_2>. Note, 64-bit "
2355 "capabilities use I<datap>[0] and I<datap>[1], whereas 32-bit capabilities "
2356 "use only I<datap>[0]."
2360 #: build/C/man2/capget.2:112
2362 "Another change affecting the behavior of these system calls is kernel "
2363 "support for file capabilities (VFS capability support). This support is "
2364 "currently a compile time option (added in kernel 2.6.24)."
2368 #: build/C/man2/capget.2:119
2370 "For B<capget>() calls, one can probe the capabilities of any process by "
2371 "specifying its process ID with the I<hdrp-E<gt>pid> field value."
2375 #: build/C/man2/capget.2:119
2377 msgid "With VFS capability support"
2381 #: build/C/man2/capget.2:131
2383 "VFS Capability support creates a file-attribute method for adding "
2384 "capabilities to privileged executables. This privilege model obsoletes "
2385 "kernel support for one process asynchronously setting the capabilities of "
2386 "another. That is, with VFS support, for B<capset>() calls the only "
2387 "permitted values for I<hdrp-E<gt>pid> are 0 or B<getpid>(2), which are "
2392 #: build/C/man2/capget.2:131
2394 msgid "Without VFS capability support"
2398 #: build/C/man2/capget.2:157
2400 "When the kernel does not support VFS capabilities, B<capset>() calls can "
2401 "operate on the capabilities of the thread specified by the I<pid> field of "
2402 "I<hdrp> when that is nonzero, or on the capabilities of the calling thread "
2403 "if I<pid> is 0. If I<pid> refers to a single-threaded process, then I<pid> "
2404 "can be specified as a traditional process ID; operating on a thread of a "
2405 "multithreaded process requires a thread ID of the type returned by "
2406 "B<gettid>(2). For B<capset>(), I<pid> can also be: -1, meaning perform the "
2407 "change on all threads except the caller and B<init>(8); or a value less than "
2408 "-1, in which case the change is applied to all members of the process group "
2409 "whose ID is -I<pid>."
2413 #: build/C/man2/capget.2:160
2414 msgid "For details on the data, see B<capabilities>(7)."
2418 #: build/C/man2/capget.2:179
2420 "The calls will fail with the error B<EINVAL>, and set the I<version> field "
2421 "of I<hdrp> to the kernel preferred value of B<_LINUX_CAPABILITY_VERSION_?> "
2422 "when an unsupported I<version> value is specified. In this way, one can "
2423 "probe what the current preferred capability revision is."
2427 #: build/C/man2/capget.2:188
2429 "Bad memory address. I<hdrp> must not be NULL. I<datap> may be NULL only "
2430 "when the user is trying to determine the preferred capability version format "
2431 "supported by the kernel."
2435 #: build/C/man2/capget.2:188 build/C/man7/cpuset.7:1180 build/C/man7/cpuset.7:1189 build/C/man7/cpuset.7:1198 build/C/man7/cpuset.7:1208 build/C/man7/cpuset.7:1217 build/C/man7/cpuset.7:1224 build/C/man7/cpuset.7:1231 build/C/man2/getgroups.2:114 build/C/man2/getgroups.2:121 build/C/man2/getpriority.2:121 build/C/man2/getrlimit.2:440 build/C/man2/getrusage.2:190 build/C/man2/iopl.2:72 build/C/man2/ioprio_set.2:170 build/C/man2/setpgid.2:202
2441 #: build/C/man2/capget.2:191
2442 msgid "One of the arguments was invalid."
2446 #: build/C/man2/capget.2:196
2448 "An attempt was made to add a capability to the Permitted set, or to set a "
2449 "capability in the Effective or Inheritable sets that is not in the Permitted "
2454 #: build/C/man2/capget.2:215
2456 "The caller attempted to use B<capset>() to modify the capabilities of a "
2457 "thread other than itself, but lacked sufficient privilege. For kernels "
2458 "supporting VFS capabilities, this is never permitted. For kernels lacking "
2459 "VFS support, the B<CAP_SETPCAP> capability is required. (A bug in kernels "
2460 "before 2.6.11 meant that this error could also occur if a thread without "
2461 "this capability tried to change its own capabilities by specifying the "
2462 "I<pid> field as a nonzero value (i.e., the value returned by B<getpid>(2)) "
2467 #: build/C/man2/capget.2:215 build/C/man7/cpuset.7:1330 build/C/man2/getpriority.2:129 build/C/man2/getrlimit.2:464 build/C/man2/getsid.2:70 build/C/man2/ioprio_set.2:187 build/C/man2/setpgid.2:217
2473 #: build/C/man2/capget.2:218
2474 msgid "No such thread."
2478 #: build/C/man2/capget.2:220 build/C/man2/ioprio_set.2:198
2479 msgid "These system calls are Linux-specific."
2483 #: build/C/man2/capget.2:225
2485 "The portable interface to the capability querying and setting functions is "
2486 "provided by the I<libcap> library and is available here:"
2490 #: build/C/man2/capget.2:228
2493 "http://git.kernel.org/cgit\\:/linux\\:/kernel\\:/git\\:/morgan\\:\\:/libcap.git> "
2498 #: build/C/man2/capget.2:232
2499 msgid "B<clone>(2), B<gettid>(2), B<capabilities>(7)"
2503 #: build/C/man7/cpuset.7:25
2509 #: build/C/man7/cpuset.7:25 build/C/man2/getpriority.2:48 build/C/man2/ioprio_set.2:24 build/C/man7/svipc.7:27
2515 #: build/C/man7/cpuset.7:28
2516 msgid "cpuset - confine processes to processor and memory node subsets"
2520 #: build/C/man7/cpuset.7:35
2522 "The cpuset file system is a pseudo-file-system interface to the kernel "
2523 "cpuset mechanism, which is used to control the processor placement and "
2524 "memory placement of processes. It is commonly mounted at I</dev/cpuset>."
2528 #: build/C/man7/cpuset.7:52
2530 "On systems with kernels compiled with built in support for cpusets, all "
2531 "processes are attached to a cpuset, and cpusets are always present. If a "
2532 "system supports cpusets, then it will have the entry B<nodev cpuset> in the "
2533 "file I</proc/filesystems>. By mounting the cpuset file system (see the "
2534 "B<EXAMPLE> section below), the administrator can configure the cpusets on a "
2535 "system to control the processor and memory placement of processes on that "
2536 "system. By default, if the cpuset configuration on a system is not modified "
2537 "or if the cpuset file system is not even mounted, then the cpuset mechanism, "
2538 "though present, has no affect on the system's behavior."
2542 #: build/C/man7/cpuset.7:54
2543 msgid "A cpuset defines a list of CPUs and memory nodes."
2547 #: build/C/man7/cpuset.7:63
2549 "The CPUs of a system include all the logical processing units on which a "
2550 "process can execute, including, if present, multiple processor cores within "
2551 "a package and Hyper-Threads within a processor core. Memory nodes include "
2552 "all distinct banks of main memory; small and SMP systems typically have just "
2553 "one memory node that contains all the system's main memory, while NUMA "
2554 "(non-uniform memory access) systems have multiple memory nodes."
2558 #: build/C/man7/cpuset.7:73
2560 "Cpusets are represented as directories in a hierarchical pseudo-file system, "
2561 "where the top directory in the hierarchy (I</dev/cpuset>) represents the "
2562 "entire system (all online CPUs and memory nodes) and any cpuset that is the "
2563 "child (descendant) of another parent cpuset contains a subset of that "
2564 "parent's CPUs and memory nodes. The directories and files representing "
2565 "cpusets have normal file-system permissions."
2569 #: build/C/man7/cpuset.7:84
2571 "Every process in the system belongs to exactly one cpuset. A process is "
2572 "confined to only run on the CPUs in the cpuset it belongs to, and to "
2573 "allocate memory only on the memory nodes in that cpuset. When a process "
2574 "B<fork>(2)s, the child process is placed in the same cpuset as its parent. "
2575 "With sufficient privilege, a process may be moved from one cpuset to another "
2576 "and the allowed CPUs and memory nodes of an existing cpuset may be changed."
2580 #: build/C/man7/cpuset.7:92
2582 "When the system begins booting, a single cpuset is defined that includes all "
2583 "CPUs and memory nodes on the system, and all processes are in that cpuset. "
2584 "During the boot process, or later during normal system operation, other "
2585 "cpusets may be created, as subdirectories of this top cpuset, under the "
2586 "control of the system administrator, and processes may be placed in these "
2591 #: build/C/man7/cpuset.7:114
2593 "Cpusets are integrated with the B<sched_setaffinity>(2) scheduling affinity "
2594 "mechanism and the B<mbind>(2) and B<set_mempolicy>(2) memory-placement "
2595 "mechanisms in the kernel. Neither of these mechanisms let a process make "
2596 "use of a CPU or memory node that is not allowed by that process's cpuset. "
2597 "If changes to a process's cpuset placement conflict with these other "
2598 "mechanisms, then cpuset placement is enforced even if it means overriding "
2599 "these other mechanisms. The kernel accomplishes this overriding by silently "
2600 "restricting the CPUs and memory nodes requested by these other mechanisms to "
2601 "those allowed by the invoking process's cpuset. This can result in these "
2602 "other calls returning an error, if for example, such a call ends up "
2603 "requesting an empty set of CPUs or memory nodes, after that request is "
2604 "restricted to the invoking process's cpuset."
2608 #: build/C/man7/cpuset.7:120
2610 "Typically, a cpuset is used to manage the CPU and memory-node confinement "
2611 "for a set of cooperating processes such as a batch scheduler job, and these "
2612 "other mechanisms are used to manage the placement of individual processes or "
2613 "memory regions within that set or job."
2617 #: build/C/man7/cpuset.7:120
2623 #: build/C/man7/cpuset.7:125
2625 "Each directory below I</dev/cpuset> represents a cpuset and contains a fixed "
2626 "set of pseudo-files describing the state of that cpuset."
2630 #: build/C/man7/cpuset.7:135
2632 "New cpusets are created using the B<mkdir>(2) system call or the "
2633 "B<mkdir>(1) command. The properties of a cpuset, such as its flags, "
2634 "allowed CPUs and memory nodes, and attached processes, are queried and "
2635 "modified by reading or writing to the appropriate file in that cpuset's "
2636 "directory, as listed below."
2640 #: build/C/man7/cpuset.7:141
2642 "The pseudo-files in each cpuset directory are automatically created when the "
2643 "cpuset is created, as a result of the B<mkdir>(2) invocation. It is not "
2644 "possible to directly add or remove these pseudo-files."
2648 #: build/C/man7/cpuset.7:149
2650 "A cpuset directory that contains no child cpuset directories, and has no "
2651 "attached processes, can be removed using B<rmdir>(2) or B<rmdir>(1). It is "
2652 "not necessary, or possible, to remove the pseudo-files inside the directory "
2653 "before removing it."
2657 #: build/C/man7/cpuset.7:163
2659 "The pseudo-files in each cpuset directory are small text files that may be "
2660 "read and written using traditional shell utilities such as B<cat>(1), and "
2661 "B<echo>(1), or from a program by using file I/O library functions or system "
2662 "calls, such as B<open>(2), B<read>(2), B<write>(2), and B<close>(2)."
2665 #. ====================== tasks ======================
2667 #: build/C/man7/cpuset.7:168
2669 "The pseudo-files in a cpuset directory represent internal kernel state and "
2670 "do not have any persistent image on disk. Each of these per-cpuset files is "
2671 "listed and described below."
2675 #: build/C/man7/cpuset.7:168
2681 #: build/C/man7/cpuset.7:178
2683 "List of the process IDs (PIDs) of the processes in that cpuset. The list is "
2684 "formatted as a series of ASCII decimal numbers, each followed by a newline. "
2685 "A process may be added to a cpuset (automatically removing it from the "
2686 "cpuset that previously contained it) by writing its PID to that cpuset's "
2687 "I<tasks> file (with or without a trailing newline.)"
2690 #. =================== notify_on_release ===================
2692 #: build/C/man7/cpuset.7:186
2694 "B<Warning:> only one PID may be written to the I<tasks> file at a time. If "
2695 "a string is written that contains more than one PID, only the first one will "
2700 #: build/C/man7/cpuset.7:186
2702 msgid "I<notify_on_release>"
2705 #. ====================== cpus ======================
2707 #: build/C/man7/cpuset.7:195
2709 "Flag (0 or 1). If set (1), that cpuset will receive special handling after "
2710 "it is released, that is, after all processes cease using it (i.e., terminate "
2711 "or are moved to a different cpuset) and all child cpuset directories have "
2712 "been removed. See the B<Notify On Release> section, below."
2716 #: build/C/man7/cpuset.7:195
2718 msgid "I<cpuset.cpus>"
2722 #: build/C/man7/cpuset.7:202
2724 "List of the physical numbers of the CPUs on which processes in that cpuset "
2725 "are allowed to execute. See B<List Format> below for a description of the "
2726 "format of I<cpus>."
2729 #. ==================== cpu_exclusive ====================
2731 #: build/C/man7/cpuset.7:208
2733 "The CPUs allowed to a cpuset may be changed by writing a new list to its "
2738 #: build/C/man7/cpuset.7:208
2740 msgid "I<cpuset.cpu_exclusive>"
2744 #: build/C/man7/cpuset.7:215
2746 "Flag (0 or 1). If set (1), the cpuset has exclusive use of its CPUs (no "
2747 "sibling or cousin cpuset may overlap CPUs). By default this is off (0). "
2748 "Newly created cpusets also initially default this to off (0)."
2751 #. ====================== mems ======================
2753 #: build/C/man7/cpuset.7:237
2755 "Two cpusets are I<sibling> cpusets if they share the same parent cpuset in "
2756 "the I</dev/cpuset> hierarchy. Two cpusets are I<cousin> cpusets if neither "
2757 "is the ancestor of the other. Regardless of the I<cpu_exclusive> setting, "
2758 "if one cpuset is the ancestor of another, and if both of these cpusets have "
2759 "nonempty I<cpus>, then their I<cpus> must overlap, because the I<cpus> of "
2760 "any cpuset are always a subset of the I<cpus> of its parent cpuset."
2764 #: build/C/man7/cpuset.7:237
2766 msgid "I<cpuset.mems>"
2769 #. ==================== mem_exclusive ====================
2771 #: build/C/man7/cpuset.7:245
2773 "List of memory nodes on which processes in this cpuset are allowed to "
2774 "allocate memory. See B<List Format> below for a description of the format "
2779 #: build/C/man7/cpuset.7:245
2781 msgid "I<cpuset.mem_exclusive>"
2785 #: build/C/man7/cpuset.7:253
2787 "Flag (0 or 1). If set (1), the cpuset has exclusive use of its memory nodes "
2788 "(no sibling or cousin may overlap). Also if set (1), the cpuset is a "
2789 "B<Hardwall> cpuset (see below.) By default this is off (0). Newly created "
2790 "cpusets also initially default this to off (0)."
2793 #. ==================== mem_hardwall ====================
2795 #: build/C/man7/cpuset.7:261
2797 "Regardless of the I<mem_exclusive> setting, if one cpuset is the ancestor of "
2798 "another, then their memory nodes must overlap, because the memory nodes of "
2799 "any cpuset are always a subset of the memory nodes of that cpuset's parent "
2804 #: build/C/man7/cpuset.7:261
2806 msgid "I<cpuset.mem_hardwall> (since Linux 2.6.26)"
2809 #. ==================== memory_migrate ====================
2811 #: build/C/man7/cpuset.7:272
2813 "Flag (0 or 1). If set (1), the cpuset is a B<Hardwall> cpuset (see below.) "
2814 "Unlike B<mem_exclusive>, there is no constraint on whether cpusets marked "
2815 "B<mem_hardwall> may have overlapping memory nodes with sibling or cousin "
2816 "cpusets. By default this is off (0). Newly created cpusets also initially "
2817 "default this to off (0)."
2821 #: build/C/man7/cpuset.7:272
2823 msgid "I<cpuset.memory_migrate> (since Linux 2.6.16)"
2826 #. ==================== memory_pressure ====================
2828 #: build/C/man7/cpuset.7:279
2830 "Flag (0 or 1). If set (1), then memory migration is enabled. By default "
2831 "this is off (0). See the B<Memory Migration> section, below."
2835 #: build/C/man7/cpuset.7:279
2837 msgid "I<cpuset.memory_pressure> (since Linux 2.6.16)"
2840 #. ================= memory_pressure_enabled =================
2842 #: build/C/man7/cpuset.7:292
2844 "A measure of how much memory pressure the processes in this cpuset are "
2845 "causing. See the B<Memory Pressure> section, below. Unless "
2846 "I<memory_pressure_enabled> is enabled, always has value zero (0). This file "
2847 "is read-only. See the B<WARNINGS> section, below."
2851 #: build/C/man7/cpuset.7:292
2853 msgid "I<cpuset.memory_pressure_enabled> (since Linux 2.6.16)"
2856 #. ================== memory_spread_page ==================
2858 #: build/C/man7/cpuset.7:304
2860 "Flag (0 or 1). This file is only present in the root cpuset, normally "
2861 "I</dev/cpuset>. If set (1), the I<memory_pressure> calculations are enabled "
2862 "for all cpusets in the system. By default this is off (0). See the "
2863 "B<Memory Pressure> section, below."
2867 #: build/C/man7/cpuset.7:304
2869 msgid "I<cpuset.memory_spread_page> (since Linux 2.6.17)"
2872 #. ================== memory_spread_slab ==================
2874 #: build/C/man7/cpuset.7:314
2876 "Flag (0 or 1). If set (1), pages in the kernel page cache (file-system "
2877 "buffers) are uniformly spread across the cpuset. By default this is off (0) "
2878 "in the top cpuset, and inherited from the parent cpuset in newly created "
2879 "cpusets. See the B<Memory Spread> section, below."
2883 #: build/C/man7/cpuset.7:314
2885 msgid "I<cpuset.memory_spread_slab> (since Linux 2.6.17)"
2888 #. ================== sched_load_balance ==================
2890 #: build/C/man7/cpuset.7:325
2892 "Flag (0 or 1). If set (1), the kernel slab caches for file I/O (directory "
2893 "and inode structures) are uniformly spread across the cpuset. By default "
2894 "this is off (0) in the top cpuset, and inherited from the parent cpuset in "
2895 "newly created cpusets. See the B<Memory Spread> section, below."
2899 #: build/C/man7/cpuset.7:325
2901 msgid "I<cpuset.sched_load_balance> (since Linux 2.6.24)"
2904 #. ================== sched_relax_domain_level ==================
2906 #: build/C/man7/cpuset.7:339
2908 "Flag (0 or 1). If set (1, the default) the kernel will automatically load "
2909 "balance processes in that cpuset over the allowed CPUs in that cpuset. If "
2910 "cleared (0) the kernel will avoid load balancing processes in this cpuset, "
2911 "I<unless> some other cpuset with overlapping CPUs has its "
2912 "I<sched_load_balance> flag set. See B<Scheduler Load Balancing>, below, for "
2917 #: build/C/man7/cpuset.7:339
2919 msgid "I<cpuset.sched_relax_domain_level> (since Linux 2.6.26)"
2922 #. ================== proc cpuset ==================
2924 #: build/C/man7/cpuset.7:359
2926 "Integer, between -1 and a small positive value. The "
2927 "I<sched_relax_domain_level> controls the width of the range of CPUs over "
2928 "which the kernel scheduler performs immediate rebalancing of runnable tasks "
2929 "across CPUs. If I<sched_load_balance> is disabled, then the setting of "
2930 "I<sched_relax_domain_level> does not matter, as no such load balancing is "
2931 "done. If I<sched_load_balance> is enabled, then the higher the value of the "
2932 "I<sched_relax_domain_level>, the wider the range of CPUs over which "
2933 "immediate load balancing is attempted. See B<Scheduler Relax Domain Level>, "
2934 "below, for further details."
2937 #. ================== proc status ==================
2939 #: build/C/man7/cpuset.7:367
2941 "In addition to the above pseudo-files in each directory below "
2942 "I</dev/cpuset>, each process has a pseudo-file, "
2943 "I</proc/E<lt>pidE<gt>/cpuset>, that displays the path of the process's "
2944 "cpuset directory relative to the root of the cpuset file system."
2948 #: build/C/man7/cpuset.7:378
2950 "Also the I</proc/E<lt>pidE<gt>/status> file for each process has four added "
2951 "lines, displaying the process's I<Cpus_allowed> (on which CPUs it may be "
2952 "scheduled) and I<Mems_allowed> (on which memory nodes it may obtain memory), "
2953 "in the two formats B<Mask Format> and B<List Format> (see below) as shown "
2954 "in the following example:"
2958 #: build/C/man7/cpuset.7:385
2961 "Cpus_allowed: ffffffff,ffffffff,ffffffff,ffffffff\n"
2962 "Cpus_allowed_list: 0-127\n"
2963 "Mems_allowed: ffffffff,ffffffff\n"
2964 "Mems_allowed_list: 0-63\n"
2967 #. ================== EXTENDED CAPABILITIES ==================
2969 #: build/C/man7/cpuset.7:391
2971 "The \"allowed\" fields were added in Linux 2.6.24; the \"allowed_list\" "
2972 "fields were added in Linux 2.6.26."
2976 #: build/C/man7/cpuset.7:391
2978 msgid "EXTENDED CAPABILITIES"
2981 #. ================== Exclusive Cpusets ==================
2983 #: build/C/man7/cpuset.7:399
2985 "In addition to controlling which I<cpus> and I<mems> a process is allowed to "
2986 "use, cpusets provide the following extended capabilities."
2990 #: build/C/man7/cpuset.7:399
2992 msgid "Exclusive cpusets"
2996 #: build/C/man7/cpuset.7:406
2998 "If a cpuset is marked I<cpu_exclusive> or I<mem_exclusive>, no other cpuset, "
2999 "other than a direct ancestor or descendant, may share any of the same CPUs "
3003 #. ================== Hardwall ==================
3005 #: build/C/man7/cpuset.7:432
3007 "A cpuset that is I<mem_exclusive> restricts kernel allocations for buffer "
3008 "cache pages and other internal kernel data pages commonly shared by the "
3009 "kernel across multiple users. All cpusets, whether I<mem_exclusive> or not, "
3010 "restrict allocations of memory for user space. This enables configuring a "
3011 "system so that several independent jobs can share common kernel data, while "
3012 "isolating each job's user allocation in its own cpuset. To do this, "
3013 "construct a large I<mem_exclusive> cpuset to hold all the jobs, and "
3014 "construct child, non-I<mem_exclusive> cpusets for each individual job. Only "
3015 "a small amount of kernel memory, such as requests from interrupt handlers, "
3016 "is allowed to be placed on memory nodes outside even a I<mem_exclusive> "
3021 #: build/C/man7/cpuset.7:432
3027 #: build/C/man7/cpuset.7:447
3029 "A cpuset that has I<mem_exclusive> or I<mem_hardwall> set is a I<hardwall> "
3030 "cpuset. A I<hardwall> cpuset restricts kernel allocations for page, buffer, "
3031 "and other data commonly shared by the kernel across multiple users. All "
3032 "cpusets, whether I<hardwall> or not, restrict allocations of memory for user "
3037 #: build/C/man7/cpuset.7:458
3039 "This enables configuring a system so that several independent jobs can share "
3040 "common kernel data, such as file system pages, while isolating each job's "
3041 "user allocation in its own cpuset. To do this, construct a large "
3042 "I<hardwall> cpuset to hold all the jobs, and construct child cpusets for "
3043 "each individual job which are not I<hardwall> cpusets."
3046 #. ================== Notify On Release ==================
3048 #: build/C/man7/cpuset.7:464
3050 "Only a small amount of kernel memory, such as requests from interrupt "
3051 "handlers, is allowed to be taken outside even a I<hardwall> cpuset."
3055 #: build/C/man7/cpuset.7:464
3057 msgid "Notify on release"
3061 #: build/C/man7/cpuset.7:476
3063 "If the I<notify_on_release> flag is enabled (1) in a cpuset, then whenever "
3064 "the last process in the cpuset leaves (exits or attaches to some other "
3065 "cpuset) and the last child cpuset of that cpuset is removed, the kernel "
3066 "will run the command I</sbin/cpuset_release_agent>, supplying the pathname "
3067 "(relative to the mount point of the cpuset file system) of the abandoned "
3068 "cpuset. This enables automatic removal of abandoned cpusets."
3072 #: build/C/man7/cpuset.7:484
3074 "The default value of I<notify_on_release> in the root cpuset at system boot "
3075 "is disabled (0). The default value of other cpusets at creation is the "
3076 "current value of their parent's I<notify_on_release> setting."
3080 #: build/C/man7/cpuset.7:492
3082 "The command I</sbin/cpuset_release_agent> is invoked, with the name "
3083 "(I</dev/cpuset> relative path) of the to-be-released cpuset in I<argv[1]>."
3087 #: build/C/man7/cpuset.7:496
3089 "The usual contents of the command I</sbin/cpuset_release_agent> is simply "
3094 #: build/C/man7/cpuset.7:501
3098 "rmdir /dev/cpuset/$1\n"
3101 #. ================== Memory Pressure ==================
3103 #: build/C/man7/cpuset.7:509
3105 "As with other flag values below, this flag can be changed by writing an "
3106 "ASCII number 0 or 1 (with optional trailing newline) into the file, to "
3107 "clear or set the flag, respectively."
3111 #: build/C/man7/cpuset.7:509
3113 msgid "Memory pressure"
3117 #: build/C/man7/cpuset.7:515
3119 "The I<memory_pressure> of a cpuset provides a simple per-cpuset running "
3120 "average of the rate that the processes in a cpuset are attempting to free up "
3121 "in-use memory on the nodes of the cpuset to satisfy additional memory "
3126 #: build/C/man7/cpuset.7:519
3128 "This enables batch managers that are monitoring jobs running in dedicated "
3129 "cpusets to efficiently detect what level of memory pressure that job is "
3134 #: build/C/man7/cpuset.7:526
3136 "This is useful both on tightly managed systems running a wide mix of "
3137 "submitted jobs, which may choose to terminate or reprioritize jobs that are "
3138 "trying to use more memory than allowed on the nodes assigned them, and with "
3139 "tightly coupled, long-running, massively parallel scientific computing jobs "
3140 "that will dramatically fail to meet required performance goals if they start "
3141 "to use more memory than allowed to them."
3145 #: build/C/man7/cpuset.7:531
3147 "This mechanism provides a very economical way for the batch manager to "
3148 "monitor a cpuset for signs of memory pressure. It's up to the batch manager "
3149 "or other user code to decide what action to take if it detects signs of "
3154 #: build/C/man7/cpuset.7:538
3156 "Unless memory pressure calculation is enabled by setting the pseudo-file "
3157 "I</dev/cpuset/cpuset.memory_pressure_enabled>, it is not computed for any "
3158 "cpuset, and reads from any I<memory_pressure> always return zero, as "
3159 "represented by the ASCII string \"0\\en\". See the B<WARNINGS> section, "
3164 #: build/C/man7/cpuset.7:540
3165 msgid "A per-cpuset, running average is employed for the following reasons:"
3169 #: build/C/man7/cpuset.7:545
3171 "Because this meter is per-cpuset rather than per-process or per virtual "
3172 "memory region, the system load imposed by a batch scheduler monitoring this "
3173 "metric is sharply reduced on large systems, because a scan of the tasklist "
3174 "can be avoided on each set of queries."
3178 #: build/C/man7/cpuset.7:550
3180 "Because this meter is a running average rather than an accumulating counter, "
3181 "a batch scheduler can detect memory pressure with a single read, instead of "
3182 "having to read and accumulate results for a period of time."
3186 #: build/C/man7/cpuset.7:556
3188 "Because this meter is per-cpuset rather than per-process, the batch "
3189 "scheduler can obtain the key information\\(emmemory pressure in a "
3190 "cpuset\\(emwith a single read, rather than having to query and accumulate "
3191 "results over all the (dynamically changing) set of processes in the cpuset."
3195 #: build/C/man7/cpuset.7:564
3197 "The I<memory_pressure> of a cpuset is calculated using a per-cpuset simple "
3198 "digital filter that is kept within the kernel. For each cpuset, this filter "
3199 "tracks the recent rate at which processes attached to that cpuset enter the "
3200 "kernel direct reclaim code."
3204 #: build/C/man7/cpuset.7:573
3206 "The kernel direct reclaim code is entered whenever a process has to satisfy "
3207 "a memory page request by first finding some other page to repurpose, due to "
3208 "lack of any readily available already free pages. Dirty file system pages "
3209 "are repurposed by first writing them to disk. Unmodified file system buffer "
3210 "pages are repurposed by simply dropping them, though if that page is needed "
3211 "again, it will have to be reread from disk."
3214 #. ================== Memory Spread ==================
3216 #: build/C/man7/cpuset.7:581
3218 "The I<cpuset.memory_pressure> file provides an integer number representing "
3219 "the recent (half-life of 10 seconds) rate of entries to the direct reclaim "
3220 "code caused by any process in the cpuset, in units of reclaims attempted per "
3221 "second, times 1000."
3225 #: build/C/man7/cpuset.7:581
3227 msgid "Memory spread"
3231 #: build/C/man7/cpuset.7:589
3233 "There are two Boolean flag files per cpuset that control where the kernel "
3234 "allocates pages for the file-system buffers and related in-kernel data "
3235 "structures. They are called I<cpuset.memory_spread_page> and "
3236 "I<cpuset.memory_spread_slab>."
3240 #: build/C/man7/cpuset.7:596
3242 "If the per-cpuset Boolean flag file I<cpuset.memory_spread_page> is set, "
3243 "then the kernel will spread the file-system buffers (page cache) evenly over "
3244 "all the nodes that the faulting process is allowed to use, instead of "
3245 "preferring to put those pages on the node where the process is running."
3249 #: build/C/man7/cpuset.7:604
3251 "If the per-cpuset Boolean flag file I<cpuset.memory_spread_slab> is set, "
3252 "then the kernel will spread some file-system-related slab caches, such as "
3253 "those for inodes and directory entries, evenly over all the nodes that the "
3254 "faulting process is allowed to use, instead of preferring to put those pages "
3255 "on the node where the process is running."
3259 #: build/C/man7/cpuset.7:609
3261 "The setting of these flags does not affect the data segment (see B<brk>(2)) "
3262 "or stack segment pages of a process."
3266 #: build/C/man7/cpuset.7:617
3268 "By default, both kinds of memory spreading are off and the kernel prefers to "
3269 "allocate memory pages on the node local to where the requesting process is "
3270 "running. If that node is not allowed by the process's NUMA memory policy or "
3271 "cpuset configuration or if there are insufficient free memory pages on that "
3272 "node, then the kernel looks for the nearest node that is allowed and has "
3273 "sufficient free memory."
3277 #: build/C/man7/cpuset.7:620
3279 "When new cpusets are created, they inherit the memory spread settings of "
3284 #: build/C/man7/cpuset.7:635
3286 "Setting memory spreading causes allocations for the affected page or slab "
3287 "caches to ignore the process's NUMA memory policy and be spread instead. "
3288 "However, the effect of these changes in memory placement caused by "
3289 "cpuset-specified memory spreading is hidden from the B<mbind>(2) or "
3290 "B<set_mempolicy>(2) calls. These two NUMA memory policy calls always "
3291 "appear to behave as if no cpuset-specified memory spreading is in effect, "
3292 "even if it is. If cpuset memory spreading is subsequently turned off, the "
3293 "NUMA memory policy most recently specified by these calls is automatically "
3298 #: build/C/man7/cpuset.7:644
3300 "Both I<cpuset.memory_spread_page> and I<cpuset.memory_spread_slab> are "
3301 "Boolean flag files. By default they contain \"0\", meaning that the feature "
3302 "is off for that cpuset. If a \"1\" is written to that file, that turns the "
3307 #: build/C/man7/cpuset.7:647
3309 "Cpuset-specified memory spreading behaves similarly to what is known (in "
3310 "other contexts) as round-robin or interleave memory placement."
3314 #: build/C/man7/cpuset.7:650
3316 "Cpuset-specified memory spreading can provide substantial performance "
3317 "improvements for jobs that:"
3321 #: build/C/man7/cpuset.7:650
3327 #: build/C/man7/cpuset.7:654
3329 "need to place thread-local data on memory nodes close to the CPUs which are "
3330 "running the threads that most frequently access that data; but also"
3334 #: build/C/man7/cpuset.7:654
3340 #: build/C/man7/cpuset.7:657
3342 "need to access large file-system data sets that must to be spread across the "
3343 "several nodes in the job's cpuset in order to fit."
3346 #. ================== Memory Migration ==================
3348 #: build/C/man7/cpuset.7:664
3350 "Without this policy, the memory allocation across the nodes in the job's "
3351 "cpuset can become very uneven, especially for jobs that might have just a "
3352 "single thread initializing or reading in the data set."
3356 #: build/C/man7/cpuset.7:664
3358 msgid "Memory migration"
3362 #: build/C/man7/cpuset.7:673
3364 "Normally, under the default setting (disabled) of I<cpuset.memory_migrate>, "
3365 "once a page is allocated (given a physical page of main memory) then that "
3366 "page stays on whatever node it was allocated, so long as it remains "
3367 "allocated, even if the cpuset's memory-placement policy I<mems> subsequently "
3372 #: build/C/man7/cpuset.7:679
3374 "When memory migration is enabled in a cpuset, if the I<mems> setting of the "
3375 "cpuset is changed, then any memory page in use by any process in the cpuset "
3376 "that is on a memory node that is no longer allowed will be migrated to a "
3377 "memory node that is allowed."
3381 #: build/C/man7/cpuset.7:685
3383 "Furthermore, if a process is moved into a cpuset with I<memory_migrate> "
3384 "enabled, any memory pages it uses that were on memory nodes allowed in its "
3385 "previous cpuset, but which are not allowed in its new cpuset, will be "
3386 "migrated to a memory node allowed in the new cpuset."
3389 #. ================== Scheduler Load Balancing ==================
3391 #: build/C/man7/cpuset.7:693
3393 "The relative placement of a migrated page within the cpuset is preserved "
3394 "during these migration operations if possible. For example, if the page was "
3395 "on the second valid node of the prior cpuset, then the page will be placed "
3396 "on the second valid node of the new cpuset, if possible."
3400 #: build/C/man7/cpuset.7:693
3402 msgid "Scheduler load balancing"
3406 #: build/C/man7/cpuset.7:700
3408 "The kernel scheduler automatically load balances processes. If one CPU is "
3409 "underutilized, the kernel will look for processes on other more overloaded "
3410 "CPUs and move those processes to the underutilized CPU, within the "
3411 "constraints of such placement mechanisms as cpusets and "
3412 "B<sched_setaffinity>(2)."
3416 #: build/C/man7/cpuset.7:713
3418 "The algorithmic cost of load balancing and its impact on key shared kernel "
3419 "data structures such as the process list increases more than linearly with "
3420 "the number of CPUs being balanced. For example, it costs more to load "
3421 "balance across one large set of CPUs than it does to balance across two "
3422 "smaller sets of CPUs, each of half the size of the larger set. (The precise "
3423 "relationship between the number of CPUs being balanced and the cost of load "
3424 "balancing depends on implementation details of the kernel process scheduler, "
3425 "which is subject to change over time, as improved kernel scheduler "
3426 "algorithms are implemented.)"
3430 #: build/C/man7/cpuset.7:719
3432 "The per-cpuset flag I<sched_load_balance> provides a mechanism to suppress "
3433 "this automatic scheduler load balancing in cases where it is not needed and "
3434 "suppressing it would have worthwhile performance benefits."
3438 #: build/C/man7/cpuset.7:723
3440 "By default, load balancing is done across all CPUs, except those marked "
3441 "isolated using the kernel boot time \"isolcpus=\" argument. (See "
3442 "B<Scheduler Relax Domain Level>, below, to change this default.)"
3446 #: build/C/man7/cpuset.7:726
3448 "This default load balancing across all CPUs is not well suited to the "
3449 "following two situations:"
3453 #: build/C/man7/cpuset.7:730
3455 "On large systems, load balancing across many CPUs is expensive. If the "
3456 "system is managed using cpusets to place independent jobs on separate sets "
3457 "of CPUs, full load balancing is unnecessary."
3461 #: build/C/man7/cpuset.7:734
3463 "Systems supporting real-time on some CPUs need to minimize system overhead "
3464 "on those CPUs, including avoiding process load balancing if that is not "
3469 #: build/C/man7/cpuset.7:744
3471 "When the per-cpuset flag I<sched_load_balance> is enabled (the default "
3472 "setting), it requests load balancing across all the CPUs in that cpuset's "
3473 "allowed CPUs, ensuring that load balancing can move a process (not otherwise "
3474 "pinned, as by B<sched_setaffinity>(2)) from any CPU in that cpuset to any "
3479 #: build/C/man7/cpuset.7:753
3481 "When the per-cpuset flag I<sched_load_balance> is disabled, then the "
3482 "scheduler will avoid load balancing across the CPUs in that cpuset, "
3483 "I<except> in so far as is necessary because some overlapping cpuset has "
3484 "I<sched_load_balance> enabled."
3488 #: build/C/man7/cpuset.7:761
3490 "So, for example, if the top cpuset has the flag I<sched_load_balance> "
3491 "enabled, then the scheduler will load balance across all CPUs, and the "
3492 "setting of the I<sched_load_balance> flag in other cpusets has no effect, as "
3493 "we're already fully load balancing."
3497 #: build/C/man7/cpuset.7:766
3499 "Therefore in the above two situations, the flag I<sched_load_balance> should "
3500 "be disabled in the top cpuset, and only some of the smaller, child cpusets "
3501 "would have this flag enabled."
3505 #: build/C/man7/cpuset.7:774
3507 "When doing this, you don't usually want to leave any unpinned processes in "
3508 "the top cpuset that might use nontrivial amounts of CPU, as such processes "
3509 "may be artificially constrained to some subset of CPUs, depending on the "
3510 "particulars of this flag setting in descendant cpusets. Even if such a "
3511 "process could use spare CPU cycles in some other CPUs, the kernel scheduler "
3512 "might not consider the possibility of load balancing that process to the "
3516 #. ================== Scheduler Relax Domain Level ==================
3518 #: build/C/man7/cpuset.7:780
3520 "Of course, processes pinned to a particular CPU can be left in a cpuset that "
3521 "disables I<sched_load_balance> as those processes aren't going anywhere else "
3526 #: build/C/man7/cpuset.7:780
3528 msgid "Scheduler relax domain level"
3532 #: build/C/man7/cpuset.7:801
3534 "The kernel scheduler performs immediate load balancing whenever a CPU "
3535 "becomes free or another task becomes runnable. This load balancing works to "
3536 "ensure that as many CPUs as possible are usefully employed running tasks. "
3537 "The kernel also performs periodic load balancing off the software clock "
3538 "described in I<time>(7). The setting of I<sched_relax_domain_level> only "
3539 "applies to immediate load balancing. Regardless of the "
3540 "I<sched_relax_domain_level> setting, periodic load balancing is attempted "
3541 "over all CPUs (unless disabled by turning off I<sched_load_balance>.) In "
3542 "any case, of course, tasks will only be scheduled to run on CPUs allowed by "
3543 "their cpuset, as modified by B<sched_setaffinity>(2) system calls."
3547 #: build/C/man7/cpuset.7:809
3549 "On small systems, such as those with just a few CPUs, immediate load "
3550 "balancing is useful to improve system interactivity and to minimize wasteful "
3551 "idle CPU cycles. But on large systems, attempting immediate load balancing "
3552 "across a large number of CPUs can be more costly than it is worth, depending "
3553 "on the particular performance characteristics of the job mix and the "
3558 #: build/C/man7/cpuset.7:817
3560 "The exact meaning of the small integer values of I<sched_relax_domain_level> "
3561 "will depend on internal implementation details of the kernel scheduler code "
3562 "and on the non-uniform architecture of the hardware. Both of these will "
3563 "evolve over time and vary by system architecture and kernel version."
3567 #: build/C/man7/cpuset.7:822
3569 "As of this writing, when this capability was introduced in Linux 2.6.26, on "
3570 "certain popular architectures, the positive values of "
3571 "I<sched_relax_domain_level> have the following meanings."
3575 #: build/C/man7/cpuset.7:824
3581 #: build/C/man7/cpuset.7:827
3583 "Perform immediate load balancing across Hyper-Thread siblings on the same "
3588 #: build/C/man7/cpuset.7:827
3594 #: build/C/man7/cpuset.7:829
3595 msgid "Perform immediate load balancing across other cores in the same package."
3599 #: build/C/man7/cpuset.7:829
3605 #: build/C/man7/cpuset.7:832
3607 "Perform immediate load balancing across other CPUs on the same node or "
3612 #: build/C/man7/cpuset.7:832
3618 #: build/C/man7/cpuset.7:835
3620 "Perform immediate load balancing across over several (implementation detail) "
3621 "nodes [On NUMA systems]."
3625 #: build/C/man7/cpuset.7:835
3631 #: build/C/man7/cpuset.7:838
3633 "Perform immediate load balancing across over all CPUs in system [On NUMA "
3638 #: build/C/man7/cpuset.7:847
3640 "The I<sched_relax_domain_level> value of zero (0) always means don't perform "
3641 "immediate load balancing, hence that load balancing is only done "
3642 "periodically, not immediately when a CPU becomes available or another task "
3647 #: build/C/man7/cpuset.7:855
3649 "The I<sched_relax_domain_level> value of minus one (-1) always means use "
3650 "the system default value. The system default value can vary by architecture "
3651 "and kernel version. This system default value can be changed by kernel "
3652 "boot-time \"relax_domain_level=\" argument."
3656 #: build/C/man7/cpuset.7:863
3658 "In the case of multiple overlapping cpusets which have conflicting "
3659 "I<sched_relax_domain_level> values, then the highest such value applies to "
3660 "all CPUs in any of the overlapping cpusets. In such cases, the value "
3661 "B<minus one (-1)> is the lowest value, overridden by any other value, and "
3662 "the value B<zero (0)> is the next lowest value."
3666 #: build/C/man7/cpuset.7:863
3671 #. ================== Mask Format ==================
3673 #: build/C/man7/cpuset.7:867
3674 msgid "The following formats are used to represent sets of CPUs and memory nodes."
3678 #: build/C/man7/cpuset.7:867
3684 #: build/C/man7/cpuset.7:872
3686 "The B<Mask Format> is used to represent CPU and memory-node bit masks in the "
3687 "I</proc/E<lt>pidE<gt>/status> file."
3691 #: build/C/man7/cpuset.7:880
3693 "This format displays each 32-bit word in hexadecimal (using ASCII characters "
3694 "\"0\" - \"9\" and \"a\" - \"f\"); words are filled with leading zeros, if "
3695 "required. For masks longer than one word, a comma separator is used between "
3696 "words. Words are displayed in big-endian order, which has the most "
3697 "significant bit first. The hex digits within a word are also in big-endian "
3702 #: build/C/man7/cpuset.7:883
3704 "The number of 32-bit words displayed is the minimum number needed to display "
3705 "all bits of the bit mask, based on the size of the bit mask."
3709 #: build/C/man7/cpuset.7:885
3710 msgid "Examples of the B<Mask Format>:"
3714 #: build/C/man7/cpuset.7:893
3717 "00000001 # just bit 0 set\n"
3718 "40000000,00000000,00000000 # just bit 94 set\n"
3719 "00000001,00000000,00000000 # just bit 64 set\n"
3720 "000000ff,00000000 # bits 32-39 set\n"
3721 "00000000,000E3862 # 1,5,6,11-13,17-19 set\n"
3725 #: build/C/man7/cpuset.7:897
3726 msgid "A mask with bits 0, 1, 2, 4, 8, 16, 32, and 64 set displays as:"
3730 #: build/C/man7/cpuset.7:901
3732 msgid "00000001,00000001,00010117\n"
3735 #. ================== List Format ==================
3737 #: build/C/man7/cpuset.7:908
3739 "The first \"1\" is for bit 64, the second for bit 32, the third for bit 16, "
3740 "the fourth for bit 8, the fifth for bit 4, and the \"7\" is for bits 2, 1, "
3745 #: build/C/man7/cpuset.7:908
3751 #: build/C/man7/cpuset.7:915
3753 "The B<List Format> for I<cpus> and I<mems> is a comma-separated list of CPU "
3754 "or memory-node numbers and ranges of numbers, in ASCII decimal."
3758 #: build/C/man7/cpuset.7:917
3759 msgid "Examples of the B<List Format>:"
3763 #: build/C/man7/cpuset.7:922
3766 "0-4,9 # bits 0, 1, 2, 3, 4, and 9 set\n"
3767 "0-2,7,12-14 # bits 0, 1, 2, 7, 12, 13, and 14 set\n"
3770 #. ================== RULES ==================
3772 #: build/C/man7/cpuset.7:925
3778 #: build/C/man7/cpuset.7:927
3779 msgid "The following rules apply to each cpuset:"
3783 #: build/C/man7/cpuset.7:930
3785 "Its CPUs and memory nodes must be a (possibly equal) subset of its "
3790 #: build/C/man7/cpuset.7:934
3791 msgid "It can only be marked I<cpu_exclusive> if its parent is."
3795 #: build/C/man7/cpuset.7:938
3796 msgid "It can only be marked I<mem_exclusive> if its parent is."
3800 #: build/C/man7/cpuset.7:942
3801 msgid "If it is I<cpu_exclusive>, its CPUs may not overlap any sibling."
3804 #. ================== PERMISSIONS ==================
3806 #: build/C/man7/cpuset.7:947
3807 msgid "If it is I<memory_exclusive>, its memory nodes may not overlap any sibling."
3811 #: build/C/man7/cpuset.7:947
3817 #: build/C/man7/cpuset.7:952
3819 "The permissions of a cpuset are determined by the permissions of the "
3820 "directories and pseudo-files in the cpuset file system, normally mounted at "
3825 #: build/C/man7/cpuset.7:961
3827 "For instance, a process can put itself in some other cpuset (than its "
3828 "current one) if it can write the I<tasks> file for that cpuset. This "
3829 "requires execute permission on the encompassing directories and write "
3830 "permission on the I<tasks> file."
3834 #: build/C/man7/cpuset.7:968
3836 "An additional constraint is applied to requests to place some other process "
3837 "in a cpuset. One process may not attach another to a cpuset unless it would "
3838 "have permission to send that process a signal (see B<kill>(2))."
3842 #: build/C/man7/cpuset.7:979
3844 "A process may create a child cpuset if it can access and write the parent "
3845 "cpuset directory. It can modify the CPUs or memory nodes in a cpuset if it "
3846 "can access that cpuset's directory (execute permissions on the each of the "
3847 "parent directories) and write the corresponding I<cpus> or I<mems> file."
3851 #: build/C/man7/cpuset.7:1000
3853 "There is one minor difference between the manner in which these permissions "
3854 "are evaluated and the manner in which normal file-system operation "
3855 "permissions are evaluated. The kernel interprets relative pathnames "
3856 "starting at a process's current working directory. Even if one is operating "
3857 "on a cpuset file, relative pathnames are interpreted relative to the "
3858 "process's current working directory, not relative to the process's current "
3859 "cpuset. The only ways that cpuset paths relative to a process's current "
3860 "cpuset can be used are if either the process's current working directory is "
3861 "its cpuset (it first did a B<cd> or B<chdir>(2) to its cpuset directory "
3862 "beneath I</dev/cpuset>, which is a bit unusual) or if some user code "
3863 "converts the relative cpuset path to a full file-system path."
3866 #. ================== WARNINGS ==================
3868 #: build/C/man7/cpuset.7:1015
3870 "In theory, this means that user code should specify cpusets using absolute "
3871 "pathnames, which requires knowing the mount point of the cpuset file system "
3872 "(usually, but not necessarily, I</dev/cpuset>). In practice, all user level "
3873 "code that this author is aware of simply assumes that if the cpuset file "
3874 "system is mounted, then it is mounted at I</dev/cpuset>. Furthermore, it is "
3875 "common practice for carefully written user code to verify the presence of "
3876 "the pseudo-file I</dev/cpuset/tasks> in order to verify that the cpuset "
3877 "pseudo-file system is currently mounted."
3881 #: build/C/man7/cpuset.7:1015
3887 #: build/C/man7/cpuset.7:1016
3889 msgid "Enabling memory_pressure"
3893 #: build/C/man7/cpuset.7:1025
3895 "By default, the per-cpuset file I<cpuset.memory_pressure> always contains "
3896 "zero (0). Unless this feature is enabled by writing \"1\" to the "
3897 "pseudo-file I</dev/cpuset/cpuset.memory_pressure_enabled>, the kernel does "
3898 "not compute per-cpuset I<memory_pressure>."
3902 #: build/C/man7/cpuset.7:1025
3904 msgid "Using the echo command"
3907 #. Gack! csh(1)'s echo does this
3909 #: build/C/man7/cpuset.7:1036
3911 "When using the B<echo> command at the shell prompt to change the values of "
3912 "cpuset files, beware that the built-in B<echo> command in some shells does "
3913 "not display an error message if the B<write>(2) system call fails. For "
3914 "example, if the command:"
3918 #: build/C/man7/cpuset.7:1040
3920 msgid "echo 19 E<gt> cpuset.mems\n"
3924 #: build/C/man7/cpuset.7:1053
3926 "failed because memory node 19 was not allowed (perhaps the current system "
3927 "does not have a memory node 19), then the B<echo> command might not display "
3928 "any error. It is better to use the B</bin/echo> external command to change "
3929 "cpuset file settings, as this command will display B<write>(2) errors, as "
3934 #: build/C/man7/cpuset.7:1058
3937 "/bin/echo 19 E<gt> cpuset.mems\n"
3938 "/bin/echo: write error: Invalid argument\n"
3941 #. ================== EXCEPTIONS ==================
3943 #: build/C/man7/cpuset.7:1061
3949 #: build/C/man7/cpuset.7:1062
3951 msgid "Memory placement"
3955 #: build/C/man7/cpuset.7:1065
3957 "Not all allocations of system memory are constrained by cpusets, for the "
3958 "following reasons."
3962 #: build/C/man7/cpuset.7:1080
3964 "If hot-plug functionality is used to remove all the CPUs that are currently "
3965 "assigned to a cpuset, then the kernel will automatically update the "
3966 "I<cpus_allowed> of all processes attached to CPUs in that cpuset to allow "
3967 "all CPUs. When memory hot-plug functionality for removing memory nodes is "
3968 "available, a similar exception is expected to apply there as well. In "
3969 "general, the kernel prefers to violate cpuset placement, rather than "
3970 "starving a process that has had all its allowed CPUs or memory nodes taken "
3971 "offline. User code should reconfigure cpusets to only refer to online CPUs "
3972 "and memory nodes when using hot-plug to add or remove such resources."
3976 #: build/C/man7/cpuset.7:1088
3978 "A few kernel-critical, internal memory-allocation requests, marked "
3979 "GFP_ATOMIC, must be satisfied immediately. The kernel may drop some request "
3980 "or malfunction if one of these allocations fail. If such a request cannot "
3981 "be satisfied within the current process's cpuset, then we relax the cpuset, "
3982 "and look for memory anywhere we can find it. It's better to violate the "
3983 "cpuset than stress the kernel."
3987 #: build/C/man7/cpuset.7:1092
3989 "Allocations of memory requested by kernel drivers while processing an "
3990 "interrupt lack any relevant process context, and are not confined by "
3995 #: build/C/man7/cpuset.7:1092
3997 msgid "Renaming cpusets"
4000 #. ================== ERRORS ==================
4002 #: build/C/man7/cpuset.7:1100
4004 "You can use the B<rename>(2) system call to rename cpusets. Only simple "
4005 "renaming is supported; that is, changing the name of a cpuset directory is "
4006 "permitted, but moving a directory into a different directory is not "
4011 #: build/C/man7/cpuset.7:1104
4013 "The Linux kernel implementation of cpusets sets I<errno> to specify the "
4014 "reason for a failed system call affecting cpusets."
4018 #: build/C/man7/cpuset.7:1109
4020 "The possible I<errno> settings and their meaning when set on a failed cpuset "
4021 "call are as listed below."
4025 #: build/C/man7/cpuset.7:1109
4031 #: build/C/man7/cpuset.7:1116
4033 "Attempted a B<write>(2) on a special cpuset file with a length larger than "
4034 "some kernel-determined upper limit on the length of such writes."
4038 #: build/C/man7/cpuset.7:1123
4040 "Attempted to B<write>(2) the process ID (PID) of a process to a cpuset "
4041 "I<tasks> file when one lacks permission to move that process."
4045 #: build/C/man7/cpuset.7:1129
4047 "Attempted to add, using B<write>(2), a CPU or memory node to a cpuset, when "
4048 "that CPU or memory node was not already in its parent."
4052 #: build/C/man7/cpuset.7:1137
4054 "Attempted to set, using B<write>(2), I<cpuset.cpu_exclusive> or "
4055 "I<cpuset.mem_exclusive> on a cpuset whose parent lacks the same setting."
4059 #: build/C/man7/cpuset.7:1144
4060 msgid "Attempted to B<write>(2) a I<cpuset.memory_pressure> file."
4064 #: build/C/man7/cpuset.7:1147
4065 msgid "Attempted to create a file in a cpuset directory."
4069 #: build/C/man7/cpuset.7:1147 build/C/man7/cpuset.7:1152 build/C/man7/cpuset.7:1157
4075 #: build/C/man7/cpuset.7:1152
4076 msgid "Attempted to remove, using B<rmdir>(2), a cpuset with attached processes."
4080 #: build/C/man7/cpuset.7:1157
4081 msgid "Attempted to remove, using B<rmdir>(2), a cpuset with child cpusets."
4085 #: build/C/man7/cpuset.7:1162
4087 "Attempted to remove a CPU or memory node from a cpuset that is also in a "
4088 "child of that cpuset."
4092 #: build/C/man7/cpuset.7:1162 build/C/man7/cpuset.7:1167
4098 #: build/C/man7/cpuset.7:1167
4099 msgid "Attempted to create, using B<mkdir>(2), a cpuset that already exists."
4103 #: build/C/man7/cpuset.7:1172
4104 msgid "Attempted to B<rename>(2) a cpuset to a name that already exists."
4108 #: build/C/man7/cpuset.7:1180
4110 "Attempted to B<read>(2) or B<write>(2) a cpuset file using a buffer that "
4111 "is outside the writing processes accessible address space."
4115 #: build/C/man7/cpuset.7:1189
4117 "Attempted to change a cpuset, using B<write>(2), in a way that would violate "
4118 "a I<cpu_exclusive> or I<mem_exclusive> attribute of that cpuset or any of "
4123 #: build/C/man7/cpuset.7:1198
4125 "Attempted to B<write>(2) an empty I<cpuset.cpus> or I<cpuset.mems> list to "
4126 "a cpuset which has attached processes or child cpusets."
4130 #: build/C/man7/cpuset.7:1208
4132 "Attempted to B<write>(2) a I<cpuset.cpus> or I<cpuset.mems> list which "
4133 "included a range with the second number smaller than the first number."
4137 #: build/C/man7/cpuset.7:1217
4139 "Attempted to B<write>(2) a I<cpuset.cpus> or I<cpuset.mems> list which "
4140 "included an invalid character in the string."
4144 #: build/C/man7/cpuset.7:1224
4146 "Attempted to B<write>(2) a list to a I<cpuset.cpus> file that did not "
4147 "include any online CPUs."
4151 #: build/C/man7/cpuset.7:1231
4153 "Attempted to B<write>(2) a list to a I<cpuset.mems> file that did not "
4154 "include any online memory nodes."
4158 #: build/C/man7/cpuset.7:1238
4160 "Attempted to B<write>(2) a list to a I<cpuset.mems> file that included a "
4161 "node that held no memory."
4165 #: build/C/man7/cpuset.7:1246
4167 "Attempted to B<write>(2) a string to a cpuset I<tasks> file that does not "
4168 "begin with an ASCII decimal integer."
4172 #: build/C/man7/cpuset.7:1251
4173 msgid "Attempted to B<rename>(2) a cpuset into a different directory."
4177 #: build/C/man7/cpuset.7:1258
4179 "Attempted to B<read>(2) a I</proc/E<lt>pidE<gt>/cpuset> file for a cpuset "
4180 "path that is longer than the kernel page size."
4184 #: build/C/man7/cpuset.7:1263
4186 "Attempted to create, using B<mkdir>(2), a cpuset whose base directory name "
4187 "is longer than 255 characters."
4191 #: build/C/man7/cpuset.7:1270
4193 "Attempted to create, using B<mkdir>(2), a cpuset whose full pathname, "
4194 "including the mount point (typically \"/dev/cpuset/\") prefix, is longer "
4195 "than 4095 characters."
4199 #: build/C/man7/cpuset.7:1270
4205 #: build/C/man7/cpuset.7:1275
4207 "The cpuset was removed by another process at the same time as a B<write>(2) "
4208 "was attempted on one of the pseudo-files in the cpuset directory."
4212 #: build/C/man7/cpuset.7:1280
4214 "Attempted to create, using B<mkdir>(2), a cpuset in a parent cpuset that "
4219 #: build/C/man7/cpuset.7:1287
4221 "Attempted to B<access>(2) or B<open>(2) a nonexistent file in a cpuset "
4226 #: build/C/man7/cpuset.7:1292
4228 "Insufficient memory is available within the kernel; can occur on a variety "
4229 "of system calls affecting cpusets, but only if the system is extremely short "
4234 #: build/C/man7/cpuset.7:1292 build/C/man7/cpuset.7:1304
4240 #: build/C/man7/cpuset.7:1304
4242 "Attempted to B<write>(2) the process ID (PID) of a process to a cpuset "
4243 "I<tasks> file when the cpuset had an empty I<cpuset.cpus> or empty "
4244 "I<cpuset.mems> setting."
4248 #: build/C/man7/cpuset.7:1314
4250 "Attempted to B<write>(2) an empty I<cpuset.cpus> or I<cpuset.mems> setting "
4251 "to a cpuset that has tasks attached."
4255 #: build/C/man7/cpuset.7:1319
4256 msgid "Attempted to B<rename>(2) a nonexistent cpuset."
4260 #: build/C/man7/cpuset.7:1322
4261 msgid "Attempted to remove a file from a cpuset directory."
4265 #: build/C/man7/cpuset.7:1322
4271 #: build/C/man7/cpuset.7:1330
4273 "Specified a I<cpuset.cpus> or I<cpuset.mems> list to the kernel which "
4274 "included a number too large for the kernel to set in its bit masks."
4277 #. ================== VERSIONS ==================
4279 #: build/C/man7/cpuset.7:1338
4281 "Attempted to B<write>(2) the process ID (PID) of a nonexistent process to a "
4282 "cpuset I<tasks> file."
4285 #. ================== NOTES ==================
4287 #: build/C/man7/cpuset.7:1341
4288 msgid "Cpusets appeared in version 2.6.12 of the Linux kernel."
4291 #. ================== BUGS ==================
4293 #: build/C/man7/cpuset.7:1352
4295 "Despite its name, the I<pid> parameter is actually a thread ID, and each "
4296 "thread in a threaded group can be attached to a different cpuset. The value "
4297 "returned from a call to B<gettid>(2) can be passed in the argument I<pid>."
4301 #: build/C/man7/cpuset.7:1352 build/C/man2/getpriority.2:225 build/C/man2/getrlimit.2:525 build/C/man2/ioprio_set.2:337 build/C/man2/setfsgid.2:104 build/C/man2/setfsuid.2:104
4306 #. ================== EXAMPLE ==================
4308 #: build/C/man7/cpuset.7:1365
4310 "I<cpuset.memory_pressure> cpuset files can be opened for writing, creation, "
4311 "or truncation, but then the B<write>(2) fails with I<errno> set to "
4312 "B<EACCES>, and the creation and truncation options on B<open>(2) have no "
4317 #: build/C/man7/cpuset.7:1365 build/C/man2/getrlimit.2:600
4323 #: build/C/man7/cpuset.7:1368
4325 "The following examples demonstrate querying and setting cpuset options using "
4330 #: build/C/man7/cpuset.7:1368
4332 msgid "Creating and attaching to a cpuset."
4336 #: build/C/man7/cpuset.7:1371
4338 "To create a new cpuset and attach the current command shell to it, the steps "
4343 #: build/C/man7/cpuset.7:1373 build/C/man7/cpuset.7:1412
4349 #: build/C/man7/cpuset.7:1375
4350 msgid "mkdir /dev/cpuset (if not already done)"
4354 #: build/C/man7/cpuset.7:1375 build/C/man7/cpuset.7:1418
4360 #: build/C/man7/cpuset.7:1377
4361 msgid "mount -t cpuset none /dev/cpuset (if not already done)"
4365 #: build/C/man7/cpuset.7:1377 build/C/man7/cpuset.7:1421
4371 #: build/C/man7/cpuset.7:1380
4372 msgid "Create the new cpuset using B<mkdir>(1)."
4376 #: build/C/man7/cpuset.7:1380 build/C/man7/cpuset.7:1424
4382 #: build/C/man7/cpuset.7:1382
4383 msgid "Assign CPUs and memory nodes to the new cpuset."
4387 #: build/C/man7/cpuset.7:1382 build/C/man7/cpuset.7:1429
4393 #: build/C/man7/cpuset.7:1384
4394 msgid "Attach the shell to the new cpuset."
4398 #: build/C/man7/cpuset.7:1389
4400 "For example, the following sequence of commands will set up a cpuset named "
4401 "\"Charlie\", containing just CPUs 2 and 3, and memory node 1, and then "
4402 "attach the current shell to that cpuset."
4406 #: build/C/man7/cpuset.7:1403
4409 "$B< mkdir /dev/cpuset>\n"
4410 "$B< mount -t cpuset cpuset /dev/cpuset>\n"
4411 "$B< cd /dev/cpuset>\n"
4412 "$B< mkdir Charlie>\n"
4414 "$B< /bin/echo 2-3 E<gt> cpuset.cpus>\n"
4415 "$B< /bin/echo 1 E<gt> cpuset.mems>\n"
4416 "$B< /bin/echo $$ E<gt> tasks>\n"
4417 "# The current shell is now running in cpuset Charlie\n"
4418 "# The next line should display '/Charlie'\n"
4419 "$B< cat /proc/self/cpuset>\n"
4423 #: build/C/man7/cpuset.7:1405
4425 msgid "Migrating a job to different memory nodes."
4429 #: build/C/man7/cpuset.7:1410
4431 "To migrate a job (the set of processes attached to a cpuset) to different "
4432 "CPUs and memory nodes in the system, including moving the memory pages "
4433 "currently allocated to that job, perform the following steps."
4437 #: build/C/man7/cpuset.7:1418
4439 "Let's say we want to move the job in cpuset I<alpha> (CPUs 4-7 and memory "
4440 "nodes 2-3) to a new cpuset I<beta> (CPUs 16-19 and memory nodes 8-9)."
4444 #: build/C/man7/cpuset.7:1421
4445 msgid "First create the new cpuset I<beta>."
4449 #: build/C/man7/cpuset.7:1424
4450 msgid "Then allow CPUs 16-19 and memory nodes 8-9 in I<beta>."
4454 #: build/C/man7/cpuset.7:1429
4455 msgid "Then enable I<memory_migration> in I<beta>."
4459 #: build/C/man7/cpuset.7:1434
4460 msgid "Then move each process from I<alpha> to I<beta>."
4464 #: build/C/man7/cpuset.7:1437
4465 msgid "The following sequence of commands accomplishes this."
4469 #: build/C/man7/cpuset.7:1447
4472 "$B< cd /dev/cpuset>\n"
4475 "$B< /bin/echo 16-19 E<gt> cpuset.cpus>\n"
4476 "$B< /bin/echo 8-9 E<gt> cpuset.mems>\n"
4477 "$B< /bin/echo 1 E<gt> cpuset.memory_migrate>\n"
4478 "$B< while read i; do /bin/echo $i; done E<lt> ../alpha/tasks E<gt> tasks>\n"
4482 #: build/C/man7/cpuset.7:1456
4484 "The above should move any processes in I<alpha> to I<beta>, and any memory "
4485 "held by these processes on memory nodes 2-3 to memory nodes 8-9, "
4490 #: build/C/man7/cpuset.7:1458
4491 msgid "Notice that the last step of the above sequence did not do:"
4495 #: build/C/man7/cpuset.7:1462
4497 msgid "$B< cp ../alpha/tasks tasks>\n"
4501 #: build/C/man7/cpuset.7:1473
4503 "The I<while> loop, rather than the seemingly easier use of the B<cp>(1) "
4504 "command, was necessary because only one process PID at a time may be written "
4505 "to the I<tasks> file."
4509 #: build/C/man7/cpuset.7:1481
4511 "The same effect (writing one PID at a time) as the I<while> loop can be "
4512 "accomplished more efficiently, in fewer keystrokes and in syntax that works "
4513 "on any shell, but alas more obscurely, by using the B<-u> (unbuffered) "
4514 "option of B<sed>(1):"
4518 #: build/C/man7/cpuset.7:1485
4520 msgid "$B< sed -un p E<lt> ../alpha/tasks E<gt> tasks>\n"
4524 #: build/C/man7/cpuset.7:1502
4526 "B<taskset>(1), B<get_mempolicy>(2), B<getcpu>(2), B<mbind>(2), "
4527 "B<sched_getaffinity>(2), B<sched_setaffinity>(2), B<sched_setscheduler>(2), "
4528 "B<set_mempolicy>(2), B<CPU_SET>(3), B<proc>(5), B<numa>(7), "
4529 "B<migratepages>(8), B<numactl>(8)"
4533 #: build/C/man7/cpuset.7:1505
4534 msgid "I<Documentation/cpusets.txt> in the Linux kernel source tree"
4538 #: build/C/man7/credentials.7:27
4544 #: build/C/man7/credentials.7:27
4550 #: build/C/man7/credentials.7:30
4551 msgid "credentials - process identifiers"
4555 #: build/C/man7/credentials.7:31
4557 msgid "Process ID (PID)"
4561 #: build/C/man7/credentials.7:41
4563 "Each process has a unique nonnegative integer identifier that is assigned "
4564 "when the process is created using B<fork>(2). A process can obtain its PID "
4565 "using B<getpid>(2). A PID is represented using the type I<pid_t> (defined "
4566 "in I<E<lt>sys/types.hE<gt>>)."
4569 #. .BR sched_rr_get_interval (2),
4570 #. .BR sched_getaffinity (2),
4571 #. .BR sched_setaffinity (2),
4572 #. .BR sched_getparam (2),
4573 #. .BR sched_setparam (2),
4574 #. .BR sched_setscheduler (2),
4575 #. .BR sched_getscheduler (2),
4580 #: build/C/man7/credentials.7:62
4582 "PIDs are used in a range of system calls to identify the process affected by "
4583 "the call, for example: B<kill>(2), B<ptrace>(2), B<setpriority>(2) "
4584 "B<setpgid>(2), B<setsid>(2), B<sigqueue>(3), and B<waitpid>(2)."
4588 #: build/C/man7/credentials.7:65
4589 msgid "A process's PID is preserved across an B<execve>(2)."
4593 #: build/C/man7/credentials.7:65
4595 msgid "Parent process ID (PPID)"
4599 #: build/C/man7/credentials.7:73
4601 "A process's parent process ID identifies the process that created this "
4602 "process using B<fork>(2). A process can obtain its PPID using "
4603 "B<getppid>(2). A PPID is represented using the type I<pid_t>."
4607 #: build/C/man7/credentials.7:76
4608 msgid "A process's PPID is preserved across an B<execve>(2)."
4612 #: build/C/man7/credentials.7:76
4614 msgid "Process group ID and session ID"
4618 #: build/C/man7/credentials.7:84
4620 "Each process has a session ID and a process group ID, both represented using "
4621 "the type I<pid_t>. A process can obtain its session ID using B<getsid>(2), "
4622 "and its process group ID using B<getpgrp>(2)."
4626 #: build/C/man7/credentials.7:90
4628 "A child created by B<fork>(2) inherits its parent's session ID and process "
4629 "group ID. A process's session ID and process group ID are preserved across "
4634 #: build/C/man7/credentials.7:103
4636 "Sessions and process groups are abstractions devised to support shell job "
4637 "control. A process group (sometimes called a \"job\") is a collection of "
4638 "processes that share the same process group ID; the shell creates a new "
4639 "process group for the process(es) used to execute single command or pipeline "
4640 "(e.g., the two processes created to execute the command \"ls\\ |\\ wc\" are "
4641 "placed in the same process group). A process's group membership can be set "
4642 "using B<setpgid>(2). The process whose process ID is the same as its "
4643 "process group ID is the I<process group leader> for that group."
4647 #: build/C/man7/credentials.7:115
4649 "A session is a collection of processes that share the same session ID. All "
4650 "of the members of a process group also have the same session ID (i.e., all "
4651 "of the members of a process group always belong to the same session, so that "
4652 "sessions and process groups form a strict two-level hierarchy of processes.) "
4653 "A new session is created when a process calls B<setsid>(2), which creates a "
4654 "new session whose session ID is the same as the PID of the process that "
4655 "called B<setsid>(2). The creator of the session is called the I<session "
4660 #: build/C/man7/credentials.7:115
4662 msgid "User and group identifiers"
4666 #: build/C/man7/credentials.7:123
4668 "Each process has various associated user and groups IDs. These IDs are "
4669 "integers, respectively represented using the types I<uid_t> and I<gid_t> "
4670 "(defined in I<E<lt>sys/types.hE<gt>>)."
4674 #: build/C/man7/credentials.7:125
4675 msgid "On Linux, each process has the following user and group identifiers:"
4679 #: build/C/man7/credentials.7:131
4681 "Real user ID and real group ID. These IDs determine who owns the process. "
4682 "A process can obtain its real user (group) ID using B<getuid>(2) "
4687 #: build/C/man7/credentials.7:143
4689 "Effective user ID and effective group ID. These IDs are used by the kernel "
4690 "to determine the permissions that the process will have when accessing "
4691 "shared resources such as message queues, shared memory, and semaphores. On "
4692 "most UNIX systems, these IDs also determine the permissions when accessing "
4693 "files. However, Linux uses the file system IDs described below for this "
4694 "task. A process can obtain its effective user (group) ID using "
4695 "B<geteuid>(2) (B<getegid>(2))."
4699 #: build/C/man7/credentials.7:165
4701 "Saved set-user-ID and saved set-group-ID. These IDs are used in set-user-ID "
4702 "and set-group-ID programs to save a copy of the corresponding effective IDs "
4703 "that were set when the program was executed (see B<execve>(2)). A "
4704 "set-user-ID program can assume and drop privileges by switching its "
4705 "effective user ID back and forth between the values in its real user ID and "
4706 "saved set-user-ID. This switching is done via calls to B<seteuid>(2), "
4707 "B<setreuid>(2), or B<setresuid>(2). A set-group-ID program performs the "
4708 "analogous tasks using B<setegid>(2), B<setregid>(2), or B<setresgid>(2). A "
4709 "process can obtain its saved set-user-ID (set-group-ID) using "
4710 "B<getresuid>(2) (B<getresgid>(2))."
4714 #: build/C/man7/credentials.7:182
4716 "File system user ID and file system group ID (Linux-specific). These IDs, "
4717 "in conjunction with the supplementary group IDs described below, are used to "
4718 "determine permissions for accessing files; see B<path_resolution>(7) for "
4719 "details. Whenever a process's effective user (group) ID is changed, the "
4720 "kernel also automatically changes the file system user (group) ID to the "
4721 "same value. Consequently, the file system IDs normally have the same values "
4722 "as the corresponding effective ID, and the semantics for file-permission "
4723 "checks are thus the same on Linux as on other UNIX systems. The file system "
4724 "IDs can be made to differ from the effective IDs by calling B<setfsuid>(2) "
4725 "and B<setfsgid>(2)."
4728 #. Since kernel 2.6.4, the limit is visible via the read-only file
4729 #. /proc/sys/kernel/ngroups_max.
4730 #. As at 2.6.22-rc2, this file is still read-only.
4732 #: build/C/man7/credentials.7:201
4734 "Supplementary group IDs. This is a set of additional group IDs that are "
4735 "used for permission checks when accessing files and other shared resources. "
4736 "On Linux kernels before 2.6.4, a process can be a member of up to 32 "
4737 "supplementary groups; since kernel 2.6.4, a process can be a member of up to "
4738 "65536 supplementary groups. The call I<sysconf(_SC_NGROUPS_MAX)> can be "
4739 "used to determine the number of supplementary groups of which a process may "
4740 "be a member. A process can obtain its set of supplementary group IDs using "
4741 "B<getgroups>(2), and can modify the set using B<setgroups>(2)."
4745 #: build/C/man7/credentials.7:211
4747 "A child process created by B<fork>(2) inherits copies of its parent's user "
4748 "and groups IDs. During an B<execve>(2), a process's real user and group ID "
4749 "and supplementary group IDs are preserved; the effective and saved set IDs "
4750 "may be changed, as described in B<execve>(2)."
4754 #: build/C/man7/credentials.7:214
4756 "Aside from the purposes noted above, a process's user IDs are also employed "
4757 "in a number of other contexts:"
4761 #: build/C/man7/credentials.7:217
4762 msgid "when determining the permissions for sending signals\\(emsee B<kill>(2);"
4766 #: build/C/man7/credentials.7:227
4768 "when determining the permissions for setting process-scheduling parameters "
4769 "(nice value, real time scheduling policy and priority, CPU affinity, I/O "
4770 "priority) using B<setpriority>(2), B<sched_setaffinity>(2), "
4771 "B<sched_setscheduler>(2), B<sched_setparam>(2), and B<ioprio_set>(2);"
4775 #: build/C/man7/credentials.7:230
4776 msgid "when checking resource limits; see B<getrlimit>(2);"
4780 #: build/C/man7/credentials.7:234
4782 "when checking the limit on the number of inotify instances that the process "
4783 "may create; see B<inotify>(7)."
4787 #: build/C/man7/credentials.7:240
4789 "Process IDs, parent process IDs, process group IDs, and session IDs are "
4790 "specified in POSIX.1-2001. The real, effective, and saved set user and "
4791 "groups IDs, and the supplementary group IDs, are specified in POSIX.1-2001. "
4792 "The file system user and group IDs are a Linux extension."
4796 #: build/C/man7/credentials.7:251
4798 "The POSIX threads specification requires that credentials are shared by all "
4799 "of the threads in a process. However, at the kernel level, Linux maintains "
4800 "separate user and group credentials for each thread. The NPTL threading "
4801 "implementation does some work to ensure that any change to user or group "
4802 "credentials (e.g., calls to B<setuid>(2), B<setresuid>(2)) is carried "
4803 "through to all of the POSIX threads in a process."
4807 #: build/C/man7/credentials.7:282
4809 "B<bash>(1), B<csh>(1), B<ps>(1), B<access>(2), B<execve>(2), "
4810 "B<faccessat>(2), B<fork>(2), B<getpgrp>(2), B<getpid>(2), B<getppid>(2), "
4811 "B<getsid>(2), B<kill>(2), B<killpg>(2), B<setegid>(2), B<seteuid>(2), "
4812 "B<setfsgid>(2), B<setfsuid>(2), B<setgid>(2), B<setgroups>(2), "
4813 "B<setresgid>(2), B<setresuid>(2), B<setuid>(2), B<waitpid>(2), "
4814 "B<euidaccess>(3), B<initgroups>(3), B<tcgetpgrp>(3), B<tcsetpgrp>(3), "
4815 "B<capabilities>(7), B<path_resolution>(7), B<unix>(7)"
4819 #: build/C/man2/getgid.2:25
4825 #: build/C/man2/getgid.2:25 build/C/man2/getgroups.2:31 build/C/man2/getresuid.2:28 build/C/man2/getuid.2:26 build/C/man2/setfsgid.2:31 build/C/man2/setfsuid.2:31 build/C/man2/setgid.2:29 build/C/man2/setresuid.2:26 build/C/man2/setreuid.2:45 build/C/man2/setuid.2:30
4831 #: build/C/man2/getgid.2:28
4832 msgid "getgid, getegid - get group identity"
4836 #: build/C/man2/getgid.2:30 build/C/man2/getgroups.2:38 build/C/man2/getpid.2:32 build/C/man2/getresuid.2:35 build/C/man2/getsid.2:31 build/C/man2/getuid.2:31 build/C/man2/seteuid.2:36 build/C/man2/setgid.2:36 build/C/man2/setpgid.2:53 build/C/man2/setresuid.2:33 build/C/man2/setreuid.2:52 build/C/man2/setsid.2:36 build/C/man2/setuid.2:37
4837 msgid "B<#include E<lt>unistd.hE<gt>>"
4841 #: build/C/man2/getgid.2:32 build/C/man2/getgroups.2:36 build/C/man2/getpid.2:30 build/C/man2/getuid.2:33 build/C/man2/seteuid.2:34 build/C/man2/setgid.2:34 build/C/man2/setreuid.2:50 build/C/man2/setuid.2:35
4842 msgid "B<#include E<lt>sys/types.hE<gt>>"
4846 #: build/C/man2/getgid.2:34
4847 msgid "B<gid_t getgid(void);>"
4851 #: build/C/man2/getgid.2:36
4852 msgid "B<gid_t getegid(void);>"
4856 #: build/C/man2/getgid.2:39
4857 msgid "B<getgid>() returns the real group ID of the calling process."
4861 #: build/C/man2/getgid.2:42
4862 msgid "B<getegid>() returns the effective group ID of the calling process."
4866 #: build/C/man2/getgid.2:44 build/C/man2/getpid.2:46 build/C/man2/getuid.2:45
4867 msgid "These functions are always successful."
4871 #: build/C/man2/getgid.2:46 build/C/man2/getuid.2:47
4872 msgid "POSIX.1-2001, 4.3BSD."
4876 #: build/C/man2/getgid.2:62
4878 "The original Linux B<getgid>() and B<getegid>() system calls supported "
4879 "only 16-bit group IDs. Subsequently, Linux 2.4 added B<getgid32>() and "
4880 "B<getegid32>(), supporting 32-bit IDs. The glibc B<getgid>() and "
4881 "B<getegid>() wrapper functions transparently deal with the variations "
4882 "across kernel versions."
4886 #: build/C/man2/getgid.2:67
4887 msgid "B<getresgid>(2), B<setgid>(2), B<setregid>(2), B<credentials>(7)"
4891 #: build/C/man2/getgroups.2:31
4897 #: build/C/man2/getgroups.2:34
4898 msgid "getgroups, setgroups - get/set list of supplementary group IDs"
4902 #: build/C/man2/getgroups.2:40
4903 msgid "B<int getgroups(int >I<size>B<, gid_t >I<list>B<[]);>"
4907 #: build/C/man2/getgroups.2:42
4908 msgid "B<#include E<lt>grp.hE<gt>>"
4912 #: build/C/man2/getgroups.2:44
4913 msgid "B<int setgroups(size_t >I<size>B<, const gid_t *>I<list>B<);>"
4917 #: build/C/man2/getgroups.2:52
4918 msgid "B<setgroups>(): _BSD_SOURCE"
4922 #: build/C/man2/getgroups.2:70
4924 "B<getgroups>() returns the supplementary group IDs of the calling process "
4925 "in I<list>. The argument I<size> should be set to the maximum number of "
4926 "items that can be stored in the buffer pointed to by I<list>. If the "
4927 "calling process is a member of more than I<size> supplementary groups, then "
4928 "an error results. It is unspecified whether the effective group ID of the "
4929 "calling process is included in the returned list. (Thus, an application "
4930 "should also call B<getegid>(2) and add or remove the resulting value.)"
4934 #: build/C/man2/getgroups.2:81
4936 "If I<size> is zero, I<list> is not modified, but the total number of "
4937 "supplementary group IDs for the process is returned. This allows the caller "
4938 "to determine the size of a dynamically allocated I<list> to be used in a "
4939 "further call to B<getgroups>()."
4943 #: build/C/man2/getgroups.2:92
4945 "B<setgroups>() sets the supplementary group IDs for the calling process. "
4946 "Appropriate privileges (Linux: the B<CAP_SETGID> capability) are required. "
4947 "The I<size> argument specifies the number of supplementary group IDs in the "
4948 "buffer pointed to by I<list>."
4952 #: build/C/man2/getgroups.2:99
4954 "On success, B<getgroups>() returns the number of supplementary group IDs. "
4955 "On error, -1 is returned, and I<errno> is set appropriately."
4959 #: build/C/man2/getgroups.2:106
4961 "On success, B<setgroups>() returns 0. On error, -1 is returned, and "
4962 "I<errno> is set appropriately."
4966 #: build/C/man2/getgroups.2:111
4967 msgid "I<list> has an invalid address."
4971 #: build/C/man2/getgroups.2:114
4972 msgid "B<getgroups>() can additionally fail with the following error:"
4976 #: build/C/man2/getgroups.2:118
4977 msgid "I<size> is less than the number of supplementary group IDs, but is not zero."
4981 #: build/C/man2/getgroups.2:121
4982 msgid "B<setgroups>() can additionally fail with the following errors:"
4986 #: build/C/man2/getgroups.2:127
4988 "I<size> is greater than B<NGROUPS_MAX> (32 before Linux 2.6.4; 65536 since "
4993 #: build/C/man2/getgroups.2:133
4994 msgid "The calling process has insufficient privilege."
4998 #: build/C/man2/getgroups.2:141
5000 "SVr4, 4.3BSD. The B<getgroups>() function is in POSIX.1-2001. Since "
5001 "B<setgroups>() requires privilege, it is not covered by POSIX.1-2001."
5005 #: build/C/man2/getgroups.2:149
5007 "A process can have up to B<NGROUPS_MAX> supplementary group IDs in addition "
5008 "to the effective group ID. The set of supplementary group IDs is inherited "
5009 "from the parent process, and preserved across an B<execve>(2)."
5013 #: build/C/man2/getgroups.2:152
5015 "The maximum number of supplementary group IDs can be found using "
5020 #: build/C/man2/getgroups.2:156
5023 " long ngroups_max;\n"
5024 " ngroups_max = sysconf(_SC_NGROUPS_MAX);\n"
5028 #: build/C/man2/getgroups.2:161
5030 "The maximum return value of B<getgroups>() cannot be larger than one more "
5035 #: build/C/man2/getgroups.2:171
5037 "The original Linux B<getgroups>() system call supported only 16-bit group "
5038 "IDs. Subsequently, Linux 2.4 added B<getgroups32>(), supporting 32-bit "
5039 "IDs. The glibc B<getgroups>() wrapper function transparently deals with "
5040 "the variation across kernel versions."
5044 #: build/C/man2/getgroups.2:178
5046 "B<getgid>(2), B<setgid>(2), B<getgrouplist>(3), B<initgroups>(3), "
5047 "B<capabilities>(7), B<credentials>(7)"
5051 #: build/C/man2/getpid.2:25
5057 #: build/C/man2/getpid.2:25
5063 #: build/C/man2/getpid.2:28
5064 msgid "getpid, getppid - get process identification"
5068 #: build/C/man2/getpid.2:34
5069 msgid "B<pid_t getpid(void);>"
5073 #: build/C/man2/getpid.2:36
5074 msgid "B<pid_t getppid(void);>"
5078 #: build/C/man2/getpid.2:41
5080 "B<getpid>() returns the process ID of the calling process. (This is often "
5081 "used by routines that generate unique temporary filenames.)"
5085 #: build/C/man2/getpid.2:44
5086 msgid "B<getppid>() returns the process ID of the parent of the calling process."
5090 #: build/C/man2/getpid.2:48
5091 msgid "POSIX.1-2001, 4.3BSD, SVr4."
5094 #. The following program demonstrates this "feature":
5096 #. #define _GNU_SOURCE
5097 #. #include <sys/syscall.h>
5098 #. #include <sys/wait.h>
5099 #. #include <stdio.h>
5100 #. #include <stdlib.h>
5101 #. #include <unistd.h>
5104 #. main(int argc, char *argv[])
5106 #. /* The following statement fills the getpid() cache */
5108 #. printf("parent PID = %ld
5109 #. ", (long) getpid());
5111 #. if (syscall(SYS_fork) == 0) {
5112 #. if (getpid() != syscall(SYS_getpid))
5113 #. printf("child getpid() mismatch: getpid()=%ld; "
5114 #. "syscall(SYS_getpid)=%ld
5116 #. (long) getpid(), (long) syscall(SYS_getpid));
5117 #. exit(EXIT_SUCCESS);
5122 #: build/C/man2/getpid.2:100
5124 "Since glibc version 2.3.4, the glibc wrapper function for B<getpid>() "
5125 "caches PIDs, so as to avoid additional system calls when a process calls "
5126 "B<getpid>() repeatedly. Normally this caching is invisible, but its "
5127 "correct operation relies on support in the wrapper functions for B<fork>(2), "
5128 "B<vfork>(2), and B<clone>(2): if an application bypasses the glibc wrappers "
5129 "for these system calls by using B<syscall>(2), then a call to B<getpid>() "
5130 "in the child will return the wrong value (to be precise: it will return the "
5131 "PID of the parent process). See also B<clone>(2) for discussion of a case "
5132 "where B<getpid>() may return the wrong value even when invoking B<clone>(2) "
5133 "via the glibc wrapper function."
5137 #: build/C/man2/getpid.2:110
5139 "B<clone>(2), B<fork>(2), B<kill>(2), B<exec>(3), B<mkstemp>(3), "
5140 "B<tempnam>(3), B<tmpfile>(3), B<tmpnam>(3), B<credentials>(7)"
5144 #: build/C/man2/getpriority.2:48
5150 #: build/C/man2/getpriority.2:51
5151 msgid "getpriority, setpriority - get/set program scheduling priority"
5155 #: build/C/man2/getpriority.2:53 build/C/man2/getrlimit.2:69 build/C/man2/getrusage.2:44
5156 msgid "B<#include E<lt>sys/time.hE<gt>>"
5160 #: build/C/man2/getpriority.2:55 build/C/man2/getrlimit.2:71 build/C/man2/getrusage.2:46
5161 msgid "B<#include E<lt>sys/resource.hE<gt>>"
5165 #: build/C/man2/getpriority.2:57
5166 msgid "B<int getpriority(int >I<which>B<, int >I<who>B<);>"
5170 #: build/C/man2/getpriority.2:59
5171 msgid "B<int setpriority(int >I<which>B<, int >I<who>B<, int >I<prio>B<);>"
5175 #: build/C/man2/getpriority.2:70
5177 "The scheduling priority of the process, process group, or user, as indicated "
5178 "by I<which> and I<who> is obtained with the B<getpriority>() call and set "
5179 "with the B<setpriority>() call."
5183 #: build/C/man2/getpriority.2:97
5185 "The value I<which> is one of B<PRIO_PROCESS>, B<PRIO_PGRP>, or B<PRIO_USER>, "
5186 "and I<who> is interpreted relative to I<which> (a process identifier for "
5187 "B<PRIO_PROCESS>, process group identifier for B<PRIO_PGRP>, and a user ID "
5188 "for B<PRIO_USER>). A zero value for I<who> denotes (respectively) the "
5189 "calling process, the process group of the calling process, or the real user "
5190 "ID of the calling process. I<Prio> is a value in the range -20 to 19 (but "
5191 "see the Notes below). The default priority is 0; lower priorities cause "
5192 "more favorable scheduling."
5196 #: build/C/man2/getpriority.2:107
5198 "The B<getpriority>() call returns the highest priority (lowest numerical "
5199 "value) enjoyed by any of the specified processes. The B<setpriority>() "
5200 "call sets the priorities of all of the specified processes to the specified "
5201 "value. Only the superuser may lower priorities."
5205 #: build/C/man2/getpriority.2:120
5207 "Since B<getpriority>() can legitimately return the value -1, it is "
5208 "necessary to clear the external variable I<errno> prior to the call, then "
5209 "check it afterward to determine if -1 is an error or a legitimate value. "
5210 "The B<setpriority>() call returns 0 if there is no error, or -1 if there "
5215 #: build/C/man2/getpriority.2:129
5216 msgid "I<which> was not one of B<PRIO_PROCESS>, B<PRIO_PGRP>, or B<PRIO_USER>."
5220 #: build/C/man2/getpriority.2:136
5221 msgid "No process was located using the I<which> and I<who> values specified."
5225 #: build/C/man2/getpriority.2:140
5226 msgid "In addition to the errors indicated above, B<setpriority>() may fail if:"
5230 #: build/C/man2/getpriority.2:152
5232 "The caller attempted to lower a process priority, but did not have the "
5233 "required privilege (on Linux: did not have the B<CAP_SYS_NICE> capability). "
5234 "Since Linux 2.6.12, this error only occurs if the caller attempts to set a "
5235 "process priority outside the range of the B<RLIMIT_NICE> soft resource limit "
5236 "of the target process; see B<getrlimit>(2) for details."
5240 #: build/C/man2/getpriority.2:160
5242 "A process was located, but its effective user ID did not match either the "
5243 "effective or the real user ID of the caller, and was not privileged (on "
5244 "Linux: did not have the B<CAP_SYS_NICE> capability). But see NOTES below."
5248 #: build/C/man2/getpriority.2:163
5249 msgid "SVr4, 4.4BSD (these function calls first appeared in 4.2BSD), POSIX.1-2001."
5253 #: build/C/man2/getpriority.2:169
5255 "A child created by B<fork>(2) inherits its parent's nice value. The nice "
5256 "value is preserved across B<execve>(2)."
5260 #: build/C/man2/getpriority.2:180
5262 "The degree to which their relative nice value affects the scheduling of "
5263 "processes varies across UNIX systems, and, on Linux, across kernel "
5264 "versions. Starting with kernel 2.6.23, Linux adopted an algorithm that "
5265 "causes relative differences in nice values to have a much stronger effect. "
5266 "This causes very low nice values (+19) to truly provide little CPU to a "
5267 "process whenever there is any other higher priority load on the system, and "
5268 "makes high nice values (-20) deliver most of the CPU to applications that "
5269 "require it (e.g., some audio applications)."
5273 #: build/C/man2/getpriority.2:195
5275 "The details on the condition for B<EPERM> depend on the system. The above "
5276 "description is what POSIX.1-2001 says, and seems to be followed on all "
5277 "System V-like systems. Linux kernels before 2.6.12 required the real or "
5278 "effective user ID of the caller to match the real user of the process I<who> "
5279 "(instead of its effective user ID). Linux 2.6.12 and later require the "
5280 "effective user ID of the caller to match the real or effective user ID of "
5281 "the process I<who>. All BSD-like systems (SunOS 4.1.3, Ultrix 4.2, 4.3BSD, "
5282 "FreeBSD 4.3, OpenBSD-2.5, ...) behave in the same manner as Linux 2.6.12 and "
5287 #: build/C/man2/getpriority.2:211
5289 "The actual priority range varies between kernel versions. Linux before "
5290 "1.3.36 had -infinity..15. Since kernel 1.3.43 Linux has the range -20..19. "
5291 "Within the kernel, nice values are actually represented using the "
5292 "corresponding range 40..1 (since negative numbers are error codes) and these "
5293 "are the values employed by the B<setpriority>() and B<getpriority>() "
5294 "system calls. The glibc wrapper functions for these system calls handle the "
5295 "translations between the user-land and kernel representations of the nice "
5296 "value according to the formula I<unice\\ =\\ 20\\ -\\ knice>."
5300 #: build/C/man2/getpriority.2:213
5301 msgid "On some systems, the range of nice values is -20..20."
5305 #: build/C/man2/getpriority.2:225
5307 "Including I<E<lt>sys/time.hE<gt>> is not required these days, but increases "
5308 "portability. (Indeed, I<E<lt>sys/resource.hE<gt>> defines the I<rusage> "
5309 "structure with fields of type I<struct timeval> defined in "
5310 "I<E<lt>sys/time.hE<gt>>.)"
5314 #: build/C/man2/getpriority.2:232
5316 "According to POSIX, the nice value is a per-process setting. However, under "
5317 "the current Linux/NPTL implementation of POSIX threads, the nice value is a "
5318 "per-thread attribute: different threads in the same process can have "
5319 "different nice values. Portable applications should avoid relying on the "
5320 "Linux behavior, which may be made standards conformant in the future."
5324 #: build/C/man2/getpriority.2:237
5325 msgid "B<nice>(1), B<renice>(1), B<fork>(2), B<capabilities>(7)"
5329 #: build/C/man2/getpriority.2:240
5331 "I<Documentation/scheduler/sched-nice-design.txt> in the Linux kernel source "
5332 "tree (since Linux 2.6.23)"
5336 #: build/C/man2/getresuid.2:28
5342 #: build/C/man2/getresuid.2:31
5343 msgid "getresuid, getresgid - get real, effective and saved user/group IDs"
5347 #: build/C/man2/getresuid.2:33 build/C/man2/setresuid.2:31
5348 msgid "B<#define _GNU_SOURCE> /* See feature_test_macros(7) */"
5352 #: build/C/man2/getresuid.2:37
5353 msgid "B<int getresuid(uid_t *>I<ruid>B<, uid_t *>I<euid>B<, uid_t *>I<suid>B<);>"
5357 #: build/C/man2/getresuid.2:39
5358 msgid "B<int getresgid(gid_t *>I<rgid>B<, gid_t *>I<egid>B<, gid_t *>I<sgid>B<);>"
5362 #: build/C/man2/getresuid.2:50
5364 "B<getresuid>() returns the real UID, the effective UID, and the saved "
5365 "set-user-ID of the calling process, in the arguments I<ruid>, I<euid>, and "
5366 "I<suid>, respectively. B<getresgid>() performs the analogous task for the "
5367 "process's group IDs."
5371 #: build/C/man2/getresuid.2:60
5373 "One of the arguments specified an address outside the calling program's "
5378 #: build/C/man2/getresuid.2:62
5379 msgid "These system calls appeared on Linux starting with kernel 2.1.44."
5383 #: build/C/man2/getresuid.2:67
5385 "The prototypes are given by glibc since version 2.3.2, provided "
5386 "B<_GNU_SOURCE> is defined."
5390 #: build/C/man2/getresuid.2:70 build/C/man2/setresuid.2:86
5391 msgid "These calls are nonstandard; they also appear on HP-UX and some of the BSDs."
5395 #: build/C/man2/getresuid.2:86
5397 "The original Linux B<getresuid>() and B<getresgid>() system calls "
5398 "supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added "
5399 "B<getresuid32>() and B<getresgid32>(), supporting 32-bit IDs. The glibc "
5400 "B<getresuid>() and B<getresgid>() wrapper functions transparently deal "
5401 "with the variations across kernel versions."
5405 #: build/C/man2/getresuid.2:92
5407 "B<getuid>(2), B<setresuid>(2), B<setreuid>(2), B<setuid>(2), "
5412 #: build/C/man2/getrlimit.2:64
5418 #: build/C/man2/getrlimit.2:64 build/C/man2/setsid.2:30
5424 #: build/C/man2/getrlimit.2:67
5425 msgid "getrlimit, setrlimit, prlimit - get/set resource limits"
5429 #: build/C/man2/getrlimit.2:73
5430 msgid "B<int getrlimit(int >I<resource>B<, struct rlimit *>I<rlim>B<);>"
5434 #: build/C/man2/getrlimit.2:75
5435 msgid "B<int setrlimit(int >I<resource>B<, const struct rlimit *>I<rlim>B<);>"
5439 #: build/C/man2/getrlimit.2:78
5441 "B<int prlimit(pid_t >I<pid>B<, int >I<resource>B<, const struct rlimit "
5442 "*>I<new_limit>B<,>"
5446 #: build/C/man2/getrlimit.2:80
5447 msgid "B< struct rlimit *>I<old_limit>B<);>"
5451 #: build/C/man2/getrlimit.2:88
5452 msgid "B<prlimit>(): _GNU_SOURCE && _FILE_OFFSET_BITS == 64"
5456 #: build/C/man2/getrlimit.2:97
5458 "The B<getrlimit>() and B<setrlimit>() system calls get and set resource "
5459 "limits respectively. Each resource has an associated soft and hard limit, "
5460 "as defined by the I<rlimit> structure:"
5464 #: build/C/man2/getrlimit.2:104
5468 " rlim_t rlim_cur; /* Soft limit */\n"
5469 " rlim_t rlim_max; /* Hard limit (ceiling for rlim_cur) */\n"
5474 #: build/C/man2/getrlimit.2:115
5476 "The soft limit is the value that the kernel enforces for the corresponding "
5477 "resource. The hard limit acts as a ceiling for the soft limit: an "
5478 "unprivileged process may only set its soft limit to a value in the range "
5479 "from 0 up to the hard limit, and (irreversibly) lower its hard limit. A "
5480 "privileged process (under Linux: one with the B<CAP_SYS_RESOURCE> "
5481 "capability) may make arbitrary changes to either limit value."
5485 #: build/C/man2/getrlimit.2:122
5487 "The value B<RLIM_INFINITY> denotes no limit on a resource (both in the "
5488 "structure returned by B<getrlimit>() and in the structure passed to "
5493 #: build/C/man2/getrlimit.2:126
5494 msgid "The I<resource> argument must be one of:"
5498 #: build/C/man2/getrlimit.2:126
5500 msgid "B<RLIMIT_AS>"
5503 #. since 2.0.27 / 2.1.12
5505 #: build/C/man2/getrlimit.2:146
5507 "The maximum size of the process's virtual memory (address space) in bytes. "
5508 "This limit affects calls to B<brk>(2), B<mmap>(2) and B<mremap>(2), which "
5509 "fail with the error B<ENOMEM> upon exceeding this limit. Also automatic "
5510 "stack expansion will fail (and generate a B<SIGSEGV> that kills the process "
5511 "if no alternate stack has been made available via B<sigaltstack>(2)). Since "
5512 "the value is a I<long>, on machines with a 32-bit I<long> either this limit "
5513 "is at most 2 GiB, or this resource is unlimited."
5517 #: build/C/man2/getrlimit.2:146
5519 msgid "B<RLIMIT_CORE>"
5523 #: build/C/man2/getrlimit.2:153
5525 "Maximum size of I<core> file. When 0 no core dump files are created. When "
5526 "nonzero, larger dumps are truncated to this size."
5530 #: build/C/man2/getrlimit.2:153
5532 msgid "B<RLIMIT_CPU>"
5536 #: build/C/man2/getrlimit.2:173
5538 "CPU time limit in seconds. When the process reaches the soft limit, it is "
5539 "sent a B<SIGXCPU> signal. The default action for this signal is to "
5540 "terminate the process. However, the signal can be caught, and the handler "
5541 "can return control to the main program. If the process continues to consume "
5542 "CPU time, it will be sent B<SIGXCPU> once per second until the hard limit is "
5543 "reached, at which time it is sent B<SIGKILL>. (This latter point describes "
5544 "Linux behavior. Implementations vary in how they treat processes which "
5545 "continue to consume CPU time after reaching the soft limit. Portable "
5546 "applications that need to catch this signal should perform an orderly "
5547 "termination upon first receipt of B<SIGXCPU>.)"
5551 #: build/C/man2/getrlimit.2:173
5553 msgid "B<RLIMIT_DATA>"
5557 #: build/C/man2/getrlimit.2:184
5559 "The maximum size of the process's data segment (initialized data, "
5560 "uninitialized data, and heap). This limit affects calls to B<brk>(2) and "
5561 "B<sbrk>(2), which fail with the error B<ENOMEM> upon encountering the soft "
5562 "limit of this resource."
5566 #: build/C/man2/getrlimit.2:184
5568 msgid "B<RLIMIT_FSIZE>"
5572 #: build/C/man2/getrlimit.2:196
5574 "The maximum size of files that the process may create. Attempts to extend a "
5575 "file beyond this limit result in delivery of a B<SIGXFSZ> signal. By "
5576 "default, this signal terminates a process, but a process can catch this "
5577 "signal instead, in which case the relevant system call (e.g., B<write>(2), "
5578 "B<truncate>(2)) fails with the error B<EFBIG>."
5582 #: build/C/man2/getrlimit.2:196
5584 msgid "B<RLIMIT_LOCKS> (Early Linux 2.4 only)"
5587 #. to be precise: Linux 2.4.0-test9; no longer in 2.4.25 / 2.5.65
5589 #: build/C/man2/getrlimit.2:204
5591 "A limit on the combined number of B<flock>(2) locks and B<fcntl>(2) leases "
5592 "that this process may establish."
5596 #: build/C/man2/getrlimit.2:204
5598 msgid "B<RLIMIT_MEMLOCK>"
5602 #: build/C/man2/getrlimit.2:242
5604 "The maximum number of bytes of memory that may be locked into RAM. In "
5605 "effect this limit is rounded down to the nearest multiple of the system page "
5606 "size. This limit affects B<mlock>(2) and B<mlockall>(2) and the "
5607 "B<mmap>(2) B<MAP_LOCKED> operation. Since Linux 2.6.9 it also affects the "
5608 "B<shmctl>(2) B<SHM_LOCK> operation, where it sets a maximum on the total "
5609 "bytes in shared memory segments (see B<shmget>(2)) that may be locked by "
5610 "the real user ID of the calling process. The B<shmctl>(2) B<SHM_LOCK> "
5611 "locks are accounted for separately from the per-process memory locks "
5612 "established by B<mlock>(2), B<mlockall>(2), and B<mmap>(2) B<MAP_LOCKED>; a "
5613 "process can lock bytes up to this limit in each of these two categories. In "
5614 "Linux kernels before 2.6.9, this limit controlled the amount of memory that "
5615 "could be locked by a privileged process. Since Linux 2.6.9, no limits are "
5616 "placed on the amount of memory that a privileged process may lock, and this "
5617 "limit instead governs the amount of memory that an unprivileged process may "
5622 #: build/C/man2/getrlimit.2:242
5624 msgid "B<RLIMIT_MSGQUEUE> (Since Linux 2.6.8)"
5628 #: build/C/man2/getrlimit.2:250
5630 "Specifies the limit on the number of bytes that can be allocated for POSIX "
5631 "message queues for the real user ID of the calling process. This limit is "
5632 "enforced for B<mq_open>(3). Each message queue that the user creates counts "
5633 "(until it is removed) against this limit according to the formula:"
5637 #: build/C/man2/getrlimit.2:254
5640 " bytes = attr.mq_maxmsg * sizeof(struct msg_msg *) +\n"
5641 " attr.mq_maxmsg * attr.mq_msgsize\n"
5645 #: build/C/man2/getrlimit.2:262
5647 "where I<attr> is the I<mq_attr> structure specified as the fourth argument "
5652 #: build/C/man2/getrlimit.2:268
5654 "The first addend in the formula, which includes I<sizeof(struct msg_msg *)> "
5655 "(4 bytes on Linux/i386), ensures that the user cannot create an unlimited "
5656 "number of zero-length messages (such messages nevertheless each consume some "
5657 "system memory for bookkeeping overhead)."
5661 #: build/C/man2/getrlimit.2:268
5663 msgid "B<RLIMIT_NICE> (since Linux 2.6.12, but see BUGS below)"
5667 #: build/C/man2/getrlimit.2:281
5669 "Specifies a ceiling to which the process's nice value can be raised using "
5670 "B<setpriority>(2) or B<nice>(2). The actual ceiling for the nice value is "
5671 "calculated as I<20\\ -\\ rlim_cur>. (This strangeness occurs because "
5672 "negative numbers cannot be specified as resource limit values, since they "
5673 "typically have special meanings. For example, B<RLIM_INFINITY> typically is "
5678 #: build/C/man2/getrlimit.2:281
5680 msgid "B<RLIMIT_NOFILE>"
5684 #: build/C/man2/getrlimit.2:295
5686 "Specifies a value one greater than the maximum file descriptor number that "
5687 "can be opened by this process. Attempts (B<open>(2), B<pipe>(2), B<dup>(2), "
5688 "etc.) to exceed this limit yield the error B<EMFILE>. (Historically, this "
5689 "limit was named B<RLIMIT_OFILE> on BSD.)"
5693 #: build/C/man2/getrlimit.2:295
5695 msgid "B<RLIMIT_NPROC>"
5699 #: build/C/man2/getrlimit.2:303
5701 "The maximum number of processes (or, more precisely on Linux, threads) that "
5702 "can be created for the real user ID of the calling process. Upon "
5703 "encountering this limit, B<fork>(2) fails with the error B<EAGAIN>."
5707 #: build/C/man2/getrlimit.2:303
5709 msgid "B<RLIMIT_RSS>"
5712 #. As at kernel 2.6.12, this limit still does nothing in 2.6 though
5713 #. talk of making it do something has surfaced from time to time in LKML
5716 #: build/C/man2/getrlimit.2:315
5718 "Specifies the limit (in pages) of the process's resident set (the number of "
5719 "virtual pages resident in RAM). This limit only has effect in Linux 2.4.x, "
5720 "x E<lt> 30, and there only affects calls to B<madvise>(2) specifying "
5725 #: build/C/man2/getrlimit.2:315
5727 msgid "B<RLIMIT_RTPRIO> (Since Linux 2.6.12, but see BUGS)"
5731 #: build/C/man2/getrlimit.2:322
5733 "Specifies a ceiling on the real-time priority that may be set for this "
5734 "process using B<sched_setscheduler>(2) and B<sched_setparam>(2)."
5738 #: build/C/man2/getrlimit.2:322
5740 msgid "B<RLIMIT_RTTIME> (Since Linux 2.6.25)"
5744 #: build/C/man2/getrlimit.2:334
5746 "Specifies a limit (in microseconds) on the amount of CPU time that a "
5747 "process scheduled under a real-time scheduling policy may consume without "
5748 "making a blocking system call. For the purpose of this limit, each time a "
5749 "process makes a blocking system call, the count of its consumed CPU time is "
5750 "reset to zero. The CPU time count is not reset if the process continues "
5751 "trying to use the CPU but is preempted, its time slice expires, or it calls "
5752 "B<sched_yield>(2)."
5756 #: build/C/man2/getrlimit.2:345
5758 "Upon reaching the soft limit, the process is sent a B<SIGXCPU> signal. If "
5759 "the process catches or ignores this signal and continues consuming CPU time, "
5760 "then B<SIGXCPU> will be generated once each second until the hard limit is "
5761 "reached, at which point the process is sent a B<SIGKILL> signal."
5765 #: build/C/man2/getrlimit.2:348
5767 "The intended use of this limit is to stop a runaway real-time process from "
5768 "locking up the system."
5772 #: build/C/man2/getrlimit.2:348
5774 msgid "B<RLIMIT_SIGPENDING> (Since Linux 2.6.8)"
5777 #. This replaces the /proc/sys/kernel/rtsig-max system-wide limit
5778 #. that was present in kernels <= 2.6.7. MTK Dec 04
5780 #: build/C/man2/getrlimit.2:362
5782 "Specifies the limit on the number of signals that may be queued for the real "
5783 "user ID of the calling process. Both standard and real-time signals are "
5784 "counted for the purpose of checking this limit. However, the limit is only "
5785 "enforced for B<sigqueue>(3); it is always possible to use B<kill>(2) to "
5786 "queue one instance of any of the signals that are not already queued to the "
5791 #: build/C/man2/getrlimit.2:362
5793 msgid "B<RLIMIT_STACK>"
5797 #: build/C/man2/getrlimit.2:370
5799 "The maximum size of the process stack, in bytes. Upon reaching this limit, "
5800 "a B<SIGSEGV> signal is generated. To handle this signal, a process must "
5801 "employ an alternate signal stack (B<sigaltstack>(2))."
5805 #: build/C/man2/getrlimit.2:375
5807 "Since Linux 2.6.23, this limit also determines the amount of space used for "
5808 "the process's command-line arguments and environment variables; for details, "
5813 #: build/C/man2/getrlimit.2:375
5818 #. commit c022a0acad534fd5f5d5f17280f6d4d135e74e81
5819 #. Author: Jiri Slaby <jslaby@suse.cz>
5820 #. Date: Tue May 4 18:03:50 2010 +0200
5822 #: build/C/man2/getrlimit.2:386
5824 "The Linux-specific B<prlimit>() system call combines and extends the "
5825 "functionality of B<setrlimit>() and B<getrlimit>(). It can be used to both "
5826 "set and get the resource limits of an arbitrary process."
5830 #: build/C/man2/getrlimit.2:393
5832 "The I<resource> argument has the same meaning as for B<setrlimit>() and "
5837 #: build/C/man2/getrlimit.2:411
5839 "If the I<new_limit> argument is a not NULL, then the I<rlimit> structure to "
5840 "which it points is used to set new values for the soft and hard limits for "
5841 "I<resource>. If the I<old_limit> argument is a not NULL, then a successful "
5842 "call to B<prlimit>() places the previous soft and hard limits for "
5843 "I<resource> in the I<rlimit> structure pointed to by I<old_limit>."
5846 #. FIXME this permission check is strange
5847 #. Asked about this on LKML, 7 Nov 2010
5848 #. "Inconsistent credential checking in prlimit() syscall"
5850 #: build/C/man2/getrlimit.2:430
5852 "The I<pid> argument specifies the ID of the process on which the call is to "
5853 "operate. If I<pid> is 0, then the call applies to the calling process. To "
5854 "set or get the resources of a process other than itself, the caller must "
5855 "have the B<CAP_SYS_RESOURCE> capability, or the real, effective, and saved "
5856 "set user IDs of the target process must match the real user ID of the caller "
5857 "I<and> the real, effective, and saved set group IDs of the target process "
5858 "must match the real group ID of the caller."
5862 #: build/C/man2/getrlimit.2:435
5864 "On success, these system calls return 0. On error, -1 is returned, and "
5865 "I<errno> is set appropriately."
5869 #: build/C/man2/getrlimit.2:440
5871 "A pointer argument points to a location outside the accessible address "
5876 #: build/C/man2/getrlimit.2:452
5878 "The value specified in I<resource> is not valid; or, for B<setrlimit>() or "
5879 "B<prlimit>(): I<rlim-E<gt>rlim_cur> was greater than I<rlim-E<gt>rlim_max>."
5883 #: build/C/man2/getrlimit.2:464
5885 "An unprivileged process tried to raise the hard limit; the "
5886 "B<CAP_SYS_RESOURCE> capability is required to do this. Or, the caller tried "
5887 "to increase the hard B<RLIMIT_NOFILE> limit above the current kernel maximum "
5888 "(B<NR_OPEN>). Or, the calling process did not have permission to set limits "
5889 "for the process specified by I<pid>."
5893 #: build/C/man2/getrlimit.2:468
5894 msgid "Could not find a process with the ID specified in I<pid>."
5898 #: build/C/man2/getrlimit.2:473
5900 "The B<prlimit>() system call is available since Linux 2.6.36. Library "
5901 "support is available since glibc 2.13."
5905 #: build/C/man2/getrlimit.2:477
5906 msgid "B<getrlimit>(), B<setrlimit>(): SVr4, 4.3BSD, POSIX.1-2001."
5910 #: build/C/man2/getrlimit.2:480
5911 msgid "B<prlimit>(): Linux-specific."
5915 #: build/C/man2/getrlimit.2:496
5917 "B<RLIMIT_MEMLOCK> and B<RLIMIT_NPROC> derive from BSD and are not specified "
5918 "in POSIX.1-2001; they are present on the BSDs and Linux, but on few other "
5919 "implementations. B<RLIMIT_RSS> derives from BSD and is not specified in "
5920 "POSIX.1-2001; it is nevertheless present on most implementations. "
5921 "B<RLIMIT_MSGQUEUE>, B<RLIMIT_NICE>, B<RLIMIT_RTPRIO>, B<RLIMIT_RTTIME>, and "
5922 "B<RLIMIT_SIGPENDING> are Linux-specific."
5926 #: build/C/man2/getrlimit.2:502
5928 "A child process created via B<fork>(2) inherits its parent's resource "
5929 "limits. Resource limits are preserved across B<execve>(2)."
5933 #: build/C/man2/getrlimit.2:511
5935 "One can set the resource limits of the shell using the built-in I<ulimit> "
5936 "command (I<limit> in B<csh>(1)). The shell's resource limits are inherited "
5937 "by the processes that it creates to execute commands."
5941 #: build/C/man2/getrlimit.2:516
5943 "Since Linux 2.6.24, the resource limits of any process can be inspected via "
5944 "I</proc/[pid]/limits>; see B<proc>(5)."
5948 #: build/C/man2/getrlimit.2:525
5950 "Ancient systems provided a B<vlimit>() function with a similar purpose to "
5951 "B<setrlimit>(). For backward compatibility, glibc also provides "
5952 "B<vlimit>(). All new applications should be written using B<setrlimit>()."
5955 #. FIXME prlimit() does not suffer
5956 #. https://bugzilla.kernel.org/show_bug.cgi?id=5042
5957 #. http://sources.redhat.com/bugzilla/show_bug.cgi?id=12201
5958 #. Since versions 2.13, glibc has library implementations of
5959 #. getrlimit() and setrlimit() that use prlimit() to work around
5962 #: build/C/man2/getrlimit.2:540
5964 "In older Linux kernels, the B<SIGXCPU> and B<SIGKILL> signals delivered when "
5965 "a process encountered the soft and hard B<RLIMIT_CPU> limits were delivered "
5966 "one (CPU) second later than they should have been. This was fixed in kernel "
5970 #. see http://marc.theaimsgroup.com/?l=linux-kernel&m=114008066530167&w=2
5972 #: build/C/man2/getrlimit.2:548
5974 "In 2.6.x kernels before 2.6.17, a B<RLIMIT_CPU> limit of 0 is wrongly "
5975 "treated as \"no limit\" (like B<RLIM_INFINITY>). Since Linux 2.6.17, "
5976 "setting a limit of 0 does have an effect, but is actually treated as a limit "
5980 #. See https://lwn.net/Articles/145008/
5982 #: build/C/man2/getrlimit.2:553
5984 "A kernel bug means that B<RLIMIT_RTPRIO> does not work in kernel 2.6.12; the "
5985 "problem is fixed in kernel 2.6.13."
5988 #. see http://marc.theaimsgroup.com/?l=linux-kernel&m=112256338703880&w=2
5990 #: build/C/man2/getrlimit.2:564
5992 "In kernel 2.6.12, there was an off-by-one mismatch between the priority "
5993 "ranges returned by B<getpriority>(2) and B<RLIMIT_NICE>. This had the "
5994 "effect that the actual ceiling for the nice value was calculated as I<19\\ "
5995 "-\\ rlim_cur>. This was fixed in kernel 2.6.13."
5998 #. The relevant patch, sent to LKML, seems to be
5999 #. http://thread.gmane.org/gmane.linux.kernel/273462
6000 #. From: Roland McGrath <roland <at> redhat.com>
6001 #. Subject: [PATCH 7/7] make RLIMIT_CPU/SIGXCPU per-process
6002 #. Date: 2005-01-23 23:27:46 GMT
6003 #. Tested Solaris 10, FreeBSD 9, OpenBSD 5.0
6004 #. FIXME https://bugzilla.kernel.org/show_bug.cgi?id=50951
6006 #: build/C/man2/getrlimit.2:591
6008 "Since Linux 2.6.12, if a process reaches its soft B<RLIMIT_CPU> limit and "
6009 "has a handler installed for B<SIGXCPU>, then, in addition to invoking the "
6010 "signal handler, the kernel increases the soft limit by one second. This "
6011 "behavior repeats if the process continues to consume CPU time, until the "
6012 "hard limit is reached, at which point the process is killed. Other "
6013 "implementations do not change the B<RLIMIT_CPU> soft limit in this manner, "
6014 "and the Linux behavior is probably not standards conformant; portable "
6015 "applications should avoid relying on this Linux-specific behavior. The "
6016 "Linux-specific B<RLIMIT_RTTIME> limit exhibits the same behavior when the "
6017 "soft limit is encountered."
6021 #: build/C/man2/getrlimit.2:600
6023 "Kernels before 2.4.22 did not diagnose the error B<EINVAL> for "
6024 "B<setrlimit>() when I<rlim-E<gt>rlim_cur> was greater than "
6025 "I<rlim-E<gt>rlim_max>."
6029 #: build/C/man2/getrlimit.2:603
6030 msgid "The program below demonstrates the use of B<prlimit>()."
6034 #: build/C/man2/getrlimit.2:612
6037 "#define _GNU_SOURCE\n"
6038 "#define _FILE_OFFSET_BITS 64\n"
6039 "#include E<lt>stdio.hE<gt>\n"
6040 "#include E<lt>time.hE<gt>\n"
6041 "#include E<lt>stdlib.hE<gt>\n"
6042 "#include E<lt>unistd.hE<gt>\n"
6043 "#include E<lt>sys/resource.hE<gt>\n"
6047 #: build/C/man2/getrlimit.2:615
6050 "#define errExit(msg) \tdo { perror(msg); exit(EXIT_FAILURE); \\e\n"
6055 #: build/C/man2/getrlimit.2:622
6059 "main(int argc, char *argv[])\n"
6061 " struct rlimit old, new;\n"
6062 " struct rlimit *newp;\n"
6067 #: build/C/man2/getrlimit.2:628
6070 " if (!(argc == 2 || argc == 4)) {\n"
6071 " fprintf(stderr, \"Usage: %s E<lt>pidE<gt> [E<lt>new-soft-limitE<gt> "
6073 " \"E<lt>new-hard-limitE<gt>]\\en\", argv[0]);\n"
6074 " exit(EXIT_FAILURE);\n"
6079 #: build/C/man2/getrlimit.2:630
6081 msgid " pid = atoi(argv[1]); /* PID of target process */\n"
6085 #: build/C/man2/getrlimit.2:637
6089 " if (argc == 4) {\n"
6090 " new.rlim_cur = atoi(argv[2]);\n"
6091 " new.rlim_max = atoi(argv[3]);\n"
6097 #: build/C/man2/getrlimit.2:640
6100 " /* Set CPU time limit of target process; retrieve and display\n"
6101 " previous limit */\n"
6105 #: build/C/man2/getrlimit.2:645
6108 " if (prlimit(pid, RLIMIT_CPU, newp, &old) == -1)\n"
6109 " errExit(\"prlimit-1\");\n"
6110 " printf(\"Previous limits: soft=%lld; hard=%lld\\en\",\n"
6111 " (long long) old.rlim_cur, (long long) old.rlim_max);\n"
6115 #: build/C/man2/getrlimit.2:647
6117 msgid " /* Retrieve and display new CPU time limit */\n"
6121 #: build/C/man2/getrlimit.2:652
6124 " if (prlimit(pid, RLIMIT_CPU, NULL, &old) == -1)\n"
6125 " errExit(\"prlimit-2\");\n"
6126 " printf(\"New limits: soft=%lld; hard=%lld\\en\",\n"
6127 " (long long) old.rlim_cur, (long long) old.rlim_max);\n"
6131 #: build/C/man2/getrlimit.2:655
6134 " exit(EXIT_FAILURE);\n"
6139 #: build/C/man2/getrlimit.2:674
6141 "B<prlimit>(1), B<dup>(2), B<fcntl>(2), B<fork>(2), B<getrusage>(2), "
6142 "B<mlock>(2), B<mmap>(2), B<open>(2), B<quotactl>(2), B<sbrk>(2), "
6143 "B<shmctl>(2), B<malloc>(3), B<sigqueue>(3), B<ulimit>(3), B<core>(5), "
6144 "B<capabilities>(7), B<signal>(7)"
6148 #: build/C/man2/getrusage.2:39
6154 #: build/C/man2/getrusage.2:39 build/C/man2/getsid.2:26 build/C/man2/setpgid.2:48
6160 #: build/C/man2/getrusage.2:42
6161 msgid "getrusage - get resource usage"
6165 #: build/C/man2/getrusage.2:48
6166 msgid "B<int getrusage(int >I<who>B<, struct rusage *>I<usage>B<);>"
6170 #: build/C/man2/getrusage.2:54
6172 "B<getrusage>() returns resource usage measures for I<who>, which can be one "
6177 #: build/C/man2/getrusage.2:54
6179 msgid "B<RUSAGE_SELF>"
6183 #: build/C/man2/getrusage.2:58
6185 "Return resource usage statistics for the calling process, which is the sum "
6186 "of resources used by all threads in the process."
6190 #: build/C/man2/getrusage.2:58
6192 msgid "B<RUSAGE_CHILDREN>"
6196 #: build/C/man2/getrusage.2:65
6198 "Return resource usage statistics for all children of the calling process "
6199 "that have terminated and been waited for. These statistics will include the "
6200 "resources used by grandchildren, and further removed descendants, if all of "
6201 "the intervening descendants waited on their terminated children."
6205 #: build/C/man2/getrusage.2:65
6207 msgid "B<RUSAGE_THREAD> (since Linux 2.6.26)"
6211 #: build/C/man2/getrusage.2:68
6212 msgid "Return resource usage statistics for the calling thread."
6216 #: build/C/man2/getrusage.2:72
6218 "The resource usages are returned in the structure pointed to by I<usage>, "
6219 "which has the following form:"
6223 #: build/C/man2/getrusage.2:93
6227 " struct timeval ru_utime; /* user CPU time used */\n"
6228 " struct timeval ru_stime; /* system CPU time used */\n"
6229 " long ru_maxrss; /* maximum resident set size */\n"
6230 " long ru_ixrss; /* integral shared memory size */\n"
6231 " long ru_idrss; /* integral unshared data size */\n"
6232 " long ru_isrss; /* integral unshared stack size */\n"
6233 " long ru_minflt; /* page reclaims (soft page faults) */\n"
6234 " long ru_majflt; /* page faults (hard page faults) */\n"
6235 " long ru_nswap; /* swaps */\n"
6236 " long ru_inblock; /* block input operations */\n"
6237 " long ru_oublock; /* block output operations */\n"
6238 " long ru_msgsnd; /* IPC messages sent */\n"
6239 " long ru_msgrcv; /* IPC messages received */\n"
6240 " long ru_nsignals; /* signals received */\n"
6241 " long ru_nvcsw; /* voluntary context switches */\n"
6242 " long ru_nivcsw; /* involuntary context switches */\n"
6247 #: build/C/man2/getrusage.2:101
6249 "Not all fields are completed; unmaintained fields are set to zero by the "
6250 "kernel. (The unmaintained fields are provided for compatibility with other "
6251 "systems, and because they may one day be supported on Linux.) The fields "
6252 "are interpreted as follows:"
6256 #: build/C/man2/getrusage.2:101
6262 #: build/C/man2/getrusage.2:107
6264 "This is the total amount of time spent executing in user mode, expressed in "
6265 "a I<timeval> structure (seconds plus microseconds)."
6269 #: build/C/man2/getrusage.2:107
6275 #: build/C/man2/getrusage.2:113
6277 "This is the total amount of time spent executing in kernel mode, expressed "
6278 "in a I<timeval> structure (seconds plus microseconds)."
6282 #: build/C/man2/getrusage.2:113
6284 msgid "I<ru_maxrss> (since Linux 2.6.32)"
6288 #: build/C/man2/getrusage.2:119
6290 "This is the maximum resident set size used (in kilobytes). For "
6291 "B<RUSAGE_CHILDREN>, this is the resident set size of the largest child, not "
6292 "the maximum resident set size of the process tree."
6296 #: build/C/man2/getrusage.2:119
6298 msgid "I<ru_ixrss> (unmaintained)"
6301 #. On some systems, this field records the number of signals received.
6303 #: build/C/man2/getrusage.2:125 build/C/man2/getrusage.2:130 build/C/man2/getrusage.2:135 build/C/man2/getrusage.2:147 build/C/man2/getrusage.2:159 build/C/man2/getrusage.2:165 build/C/man2/getrusage.2:169
6304 msgid "This field is currently unused on Linux."
6308 #: build/C/man2/getrusage.2:125
6310 msgid "I<ru_idrss> (unmaintained)"
6314 #: build/C/man2/getrusage.2:130
6316 msgid "I<ru_isrss> (unmaintained)"
6320 #: build/C/man2/getrusage.2:135
6322 msgid "I<ru_minflt>"
6326 #: build/C/man2/getrusage.2:140
6328 "The number of page faults serviced without any I/O activity; here I/O "
6329 "activity is avoided by ``reclaiming'' a page frame from the list of pages "
6330 "awaiting reallocation."
6334 #: build/C/man2/getrusage.2:140
6336 msgid "I<ru_majflt>"
6340 #: build/C/man2/getrusage.2:143
6341 msgid "The number of page faults serviced that required I/O activity."
6345 #: build/C/man2/getrusage.2:143
6347 msgid "I<ru_nswap> (unmaintained)"
6351 #: build/C/man2/getrusage.2:147
6353 msgid "I<ru_inblock> (since Linux 2.6.22)"
6357 #: build/C/man2/getrusage.2:150
6358 msgid "The number of times the file system had to perform input."
6362 #: build/C/man2/getrusage.2:150
6364 msgid "I<ru_oublock> (since Linux 2.6.22)"
6368 #: build/C/man2/getrusage.2:153
6369 msgid "The number of times the file system had to perform output."
6373 #: build/C/man2/getrusage.2:153
6375 msgid "I<ru_msgsnd> (unmaintained)"
6379 #: build/C/man2/getrusage.2:159
6381 msgid "I<ru_msgrcv> (unmaintained)"
6385 #: build/C/man2/getrusage.2:165
6387 msgid "I<ru_nsignals> (unmaintained)"
6391 #: build/C/man2/getrusage.2:169
6393 msgid "I<ru_nvcsw> (since Linux 2.6)"
6397 #: build/C/man2/getrusage.2:174
6399 "The number of times a context switch resulted due to a process voluntarily "
6400 "giving up the processor before its time slice was completed (usually to "
6401 "await availability of a resource)."
6405 #: build/C/man2/getrusage.2:174
6407 msgid "I<ru_nivcsw> (since Linux 2.6)"
6411 #: build/C/man2/getrusage.2:179
6413 "The number of times a context switch resulted due to a higher priority "
6414 "process becoming runnable or because the current process exceeded its time "
6419 #: build/C/man2/getrusage.2:190
6420 msgid "I<usage> points outside the accessible address space."
6424 #: build/C/man2/getrusage.2:194
6425 msgid "I<who> is invalid."
6429 #: build/C/man2/getrusage.2:202
6431 "SVr4, 4.3BSD. POSIX.1-2001 specifies B<getrusage>(), but only specifies the "
6432 "fields I<ru_utime> and I<ru_stime>."
6436 #: build/C/man2/getrusage.2:205
6437 msgid "B<RUSAGE_THREAD> is Linux-specific."
6441 #: build/C/man2/getrusage.2:208
6442 msgid "Resource usage metrics are preserved across an B<execve>(2)."
6446 #: build/C/man2/getrusage.2:216
6448 "Including I<E<lt>sys/time.hE<gt>> is not required these days, but increases "
6449 "portability. (Indeed, I<struct timeval> is defined in "
6450 "I<E<lt>sys/time.hE<gt>>.)"
6453 #. See the description of getrusage() in XSH.
6454 #. A similar statement was also in SUSv2.
6456 #: build/C/man2/getrusage.2:228
6458 "In Linux kernel versions before 2.6.9, if the disposition of B<SIGCHLD> is "
6459 "set to B<SIG_IGN> then the resource usages of child processes are "
6460 "automatically included in the value returned by B<RUSAGE_CHILDREN>, although "
6461 "POSIX.1-2001 explicitly prohibits this. This nonconformance is rectified in "
6462 "Linux 2.6.9 and later."
6466 #: build/C/man2/getrusage.2:231
6468 "The structure definition shown at the start of this page was taken from "
6473 #: build/C/man2/getrusage.2:240
6475 "Ancient systems provided a B<vtimes>() function with a similar purpose to "
6476 "B<getrusage>(). For backward compatibility, glibc also provides "
6477 "B<vtimes>(). All new applications should be written using B<getrusage>()."
6481 #: build/C/man2/getrusage.2:245
6482 msgid "See also the description of I</proc/PID/stat> in B<proc>(5)."
6486 #: build/C/man2/getrusage.2:252
6488 "B<clock_gettime>(2), B<getrlimit>(2), B<times>(2), B<wait>(2), B<wait4>(2), "
6493 #: build/C/man2/getsid.2:26
6499 #: build/C/man2/getsid.2:29
6500 msgid "getsid - get session ID"
6504 #: build/C/man2/getsid.2:33
6505 msgid "B<pid_t getsid(pid_t>I< pid>B<);>"
6509 #: build/C/man2/getsid.2:42
6510 msgid "B<getsid>():"
6514 #: build/C/man2/getsid.2:45 build/C/man2/setpgid.2:79
6515 msgid "_XOPEN_SOURCE\\ E<gt>=\\ 500 || _XOPEN_SOURCE\\ &&\\ _XOPEN_SOURCE_EXTENDED"
6519 #: build/C/man2/getsid.2:47 build/C/man2/setpgid.2:81
6520 msgid "|| /* Since glibc 2.12: */ _POSIX_C_SOURCE\\ E<gt>=\\ 200809L"
6524 #: build/C/man2/getsid.2:58
6526 "I<getsid(0)> returns the session ID of the calling process. I<getsid(p)> "
6527 "returns the session ID of the process with process ID I<p>. (The session ID "
6528 "of a process is the process group ID of the session leader.)"
6532 #: build/C/man2/getsid.2:63
6534 "On success, a session ID is returned. On error, I<(pid_t)\\ -1> will be "
6535 "returned, and I<errno> is set appropriately."
6539 #: build/C/man2/getsid.2:70
6541 "A process with process ID I<p> exists, but it is not in the same session as "
6542 "the calling process, and the implementation considers this an error."
6546 #: build/C/man2/getsid.2:75
6547 msgid "No process with process ID I<p> was found."
6550 #. Linux has this system call since Linux 1.3.44.
6551 #. There is libc support since libc 5.2.19.
6553 #: build/C/man2/getsid.2:79
6554 msgid "This system call is available on Linux since version 2.0."
6558 #: build/C/man2/getsid.2:81 build/C/man2/setgid.2:68 build/C/man2/setsid.2:67
6559 msgid "SVr4, POSIX.1-2001."
6563 #: build/C/man2/getsid.2:84
6564 msgid "Linux does not return B<EPERM>."
6568 #: build/C/man2/getsid.2:88
6569 msgid "B<getpgid>(2), B<setsid>(2), B<credentials>(7)"
6573 #: build/C/man2/getuid.2:26
6579 #: build/C/man2/getuid.2:29
6580 msgid "getuid, geteuid - get user identity"
6584 #: build/C/man2/getuid.2:35
6585 msgid "B<uid_t getuid(void);>"
6589 #: build/C/man2/getuid.2:37
6590 msgid "B<uid_t geteuid(void);>"
6594 #: build/C/man2/getuid.2:40
6595 msgid "B<getuid>() returns the real user ID of the calling process."
6599 #: build/C/man2/getuid.2:43
6600 msgid "B<geteuid>() returns the effective user ID of the calling process."
6604 #: build/C/man2/getuid.2:48
6610 #: build/C/man2/getuid.2:57
6612 "In UNIX V6 the B<getuid>() call returned I<(euid E<lt>E<lt> 8) + uid>. "
6613 "UNIX V7 introduced separate calls B<getuid>() and B<geteuid>()."
6617 #: build/C/man2/getuid.2:73
6619 "The original Linux B<getuid>() and B<geteuid>() system calls supported "
6620 "only 16-bit user IDs. Subsequently, Linux 2.4 added B<getuid32>() and "
6621 "B<geteuid32>(), supporting 32-bit IDs. The glibc B<getuid>() and "
6622 "B<geteuid>() wrapper functions transparently deal with the variations "
6623 "across kernel versions."
6627 #: build/C/man2/getuid.2:78
6628 msgid "B<getresuid>(2), B<setreuid>(2), B<setuid>(2), B<credentials>(7)"
6632 #: build/C/man2/iopl.2:33
6638 #: build/C/man2/iopl.2:33
6644 #: build/C/man2/iopl.2:36
6645 msgid "iopl - change I/O privilege level"
6649 #: build/C/man2/iopl.2:38
6650 msgid "B<#include E<lt>sys/io.hE<gt>>"
6654 #: build/C/man2/iopl.2:40
6655 msgid "B<int iopl(int >I<level>B<);>"
6659 #: build/C/man2/iopl.2:45
6661 "B<iopl>() changes the I/O privilege level of the calling process, as "
6662 "specified by the two least significant bits in I<level>."
6666 #: build/C/man2/iopl.2:51
6668 "This call is necessary to allow 8514-compatible X servers to run under "
6669 "Linux. Since these X servers require access to all 65536 I/O ports, the "
6670 "B<ioperm>(2) call is not sufficient."
6674 #: build/C/man2/iopl.2:55
6676 "In addition to granting unrestricted I/O port access, running at a higher "
6677 "I/O privilege level also allows the process to disable interrupts. This "
6678 "will probably crash the system, and is not recommended."
6682 #: build/C/man2/iopl.2:60
6683 msgid "Permissions are inherited by B<fork>(2) and B<execve>(2)."
6687 #: build/C/man2/iopl.2:62
6688 msgid "The I/O privilege level for a normal process is 0."
6692 #: build/C/man2/iopl.2:66
6694 "This call is mostly for the i386 architecture. On many other architectures "
6695 "it does not exist or will always return an error."
6699 #: build/C/man2/iopl.2:76
6700 msgid "I<level> is greater than 3."
6704 #: build/C/man2/iopl.2:79
6705 msgid "This call is unimplemented."
6709 #: build/C/man2/iopl.2:87
6711 "The calling process has insufficient privilege to call B<iopl>(); the "
6712 "B<CAP_SYS_RAWIO> capability is required to raise the I/O privilege level "
6713 "above its current value."
6717 #: build/C/man2/iopl.2:91
6719 "B<iopl>() is Linux-specific and should not be used in programs that are "
6720 "intended to be portable."
6724 #: build/C/man2/iopl.2:100
6726 "Libc5 treats it as a system call and has a prototype in "
6727 "I<E<lt>unistd.hE<gt>>. Glibc1 does not have a prototype. Glibc2 has a "
6728 "prototype both in I<E<lt>sys/io.hE<gt>> and in I<E<lt>sys/perm.hE<gt>>. "
6729 "Avoid the latter, it is available on i386 only."
6733 #: build/C/man2/iopl.2:104
6734 msgid "B<ioperm>(2), B<outb>(2), B<capabilities>(7)"
6738 #: build/C/man2/ioprio_set.2:24
6744 #: build/C/man2/ioprio_set.2:27
6745 msgid "ioprio_get, ioprio_set - get/set I/O scheduling class and priority"
6749 #: build/C/man2/ioprio_set.2:31
6752 "B<int ioprio_get(int >I<which>B<, int >I<who>B<);>\n"
6753 "B<int ioprio_set(int >I<which>B<, int >I<who>B<, int >I<ioprio>B<);>\n"
6757 #: build/C/man2/ioprio_set.2:35
6758 msgid "I<Note>: There are no glibc wrappers for these system calls; see NOTES."
6762 #: build/C/man2/ioprio_set.2:42
6764 "The B<ioprio_get>() and B<ioprio_set>() system calls respectively get and "
6765 "set the I/O scheduling class and priority of one or more threads."
6769 #: build/C/man2/ioprio_set.2:54
6771 "The I<which> and I<who> arguments identify the thread(s) on which the system "
6772 "calls operate. The I<which> argument determines how I<who> is interpreted, "
6773 "and has one of the following values:"
6777 #: build/C/man2/ioprio_set.2:54
6779 msgid "B<IOPRIO_WHO_PROCESS>"
6783 #: build/C/man2/ioprio_set.2:61
6785 "I<who> is a process ID or thread ID identifying a single process or thread. "
6786 "If I<who> is 0, then operate on the calling thread."
6790 #: build/C/man2/ioprio_set.2:61
6792 msgid "B<IOPRIO_WHO_PGRP>"
6796 #: build/C/man2/ioprio_set.2:68
6798 "I<who> is a process group ID identifying all the members of a process "
6799 "group. If I<who> is 0, then operate on the process group of which the "
6800 "caller is a member."
6804 #: build/C/man2/ioprio_set.2:68
6806 msgid "B<IOPRIO_WHO_USER>"
6809 #. FIXME who==0 needs to be documented,
6810 #. See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=652443
6812 #: build/C/man2/ioprio_set.2:75
6814 "I<who> is a user ID identifying all of the processes that have a matching "
6819 #: build/C/man2/ioprio_set.2:98
6821 "If I<which> is specified as B<IOPRIO_WHO_PGRP> or B<IOPRIO_WHO_USER> when "
6822 "calling B<ioprio_get>(), and more than one process matches I<who>, then the "
6823 "returned priority will be the highest one found among all of the matching "
6824 "processes. One priority is said to be higher than another one if it belongs "
6825 "to a higher priority class (B<IOPRIO_CLASS_RT> is the highest priority "
6826 "class; B<IOPRIO_CLASS_IDLE> is the lowest) or if it belongs to the same "
6827 "priority class as the other process but has a higher priority level (a lower "
6828 "priority number means a higher priority level)."
6832 #: build/C/man2/ioprio_set.2:108
6834 "The I<ioprio> argument given to B<ioprio_set>() is a bit mask that "
6835 "specifies both the scheduling class and the priority to be assigned to the "
6836 "target process(es). The following macros are used for assembling and "
6837 "dissecting I<ioprio> values:"
6841 #: build/C/man2/ioprio_set.2:108
6843 msgid "B<IOPRIO_PRIO_VALUE(>I<class>B<, >I<data>B<)>"
6847 #: build/C/man2/ioprio_set.2:117
6849 "Given a scheduling I<class> and priority (I<data>), this macro combines the "
6850 "two values to produce an I<ioprio> value, which is returned as the result of "
6855 #: build/C/man2/ioprio_set.2:117
6857 msgid "B<IOPRIO_PRIO_CLASS(>I<mask>B<)>"
6861 #: build/C/man2/ioprio_set.2:129
6863 "Given I<mask> (an I<ioprio> value), this macro returns its I/O class "
6864 "component, that is, one of the values B<IOPRIO_CLASS_RT>, "
6865 "B<IOPRIO_CLASS_BE>, or B<IOPRIO_CLASS_IDLE>."
6869 #: build/C/man2/ioprio_set.2:129
6871 msgid "B<IOPRIO_PRIO_DATA(>I<mask>B<)>"
6875 #: build/C/man2/ioprio_set.2:138
6877 "Given I<mask> (an I<ioprio> value), this macro returns its priority "
6878 "(I<data>) component."
6882 #: build/C/man2/ioprio_set.2:141
6884 "See the NOTES section for more information on scheduling classes and "
6889 #: build/C/man2/ioprio_set.2:149
6891 "I/O priorities are supported for reads and for synchronous (B<O_DIRECT>, "
6892 "B<O_SYNC>) writes. I/O priorities are not supported for asynchronous "
6893 "writes because they are issued outside the context of the program dirtying "
6894 "the memory, and thus program-specific priorities do not apply."
6898 #: build/C/man2/ioprio_set.2:162
6900 "On success, B<ioprio_get>() returns the I<ioprio> value of the process with "
6901 "highest I/O priority of any of the processes that match the criteria "
6902 "specified in I<which> and I<who>. On error, -1 is returned, and I<errno> is "
6903 "set to indicate the error."
6907 #: build/C/man2/ioprio_set.2:169
6909 "On success, B<ioprio_set>() returns 0. On error, -1 is returned, and "
6910 "I<errno> is set to indicate the error."
6914 #: build/C/man2/ioprio_set.2:179
6916 "Invalid value for I<which> or I<ioprio>. Refer to the NOTES section for "
6917 "available scheduler classes and priority levels for I<ioprio>."
6921 #: build/C/man2/ioprio_set.2:187
6923 "The calling process does not have the privilege needed to assign this "
6924 "I<ioprio> to the specified process(es). See the NOTES section for more "
6925 "information on required privileges for B<ioprio_set>()."
6929 #: build/C/man2/ioprio_set.2:193
6931 "No process(es) could be found that matched the specification in I<which> and "
6936 #: build/C/man2/ioprio_set.2:196
6937 msgid "These system calls have been available on Linux since kernel 2.6.13."
6941 #: build/C/man2/ioprio_set.2:201
6943 "Glibc does not provide a wrapper for these system calls; call them using "
6948 #: build/C/man2/ioprio_set.2:220
6950 "Two or more processes or threads can share an I/O context. This will be the "
6951 "case when B<clone>(2) was called with the B<CLONE_IO> flag. However, by "
6952 "default, the distinct threads of a process will B<not> share the same I/O "
6953 "context. This means that if you want to change the I/O priority of all "
6954 "threads in a process, you may need to call B<ioprio_set>() on each of the "
6955 "threads. The thread ID that you would need for this operation is the one "
6956 "that is returned by B<gettid>(2) or B<clone>(2)."
6960 #: build/C/man2/ioprio_set.2:225
6962 "These system calls only have an effect when used in conjunction with an I/O "
6963 "scheduler that supports I/O priorities. As at kernel 2.6.17 the only such "
6964 "scheduler is the Completely Fair Queuing (CFQ) I/O scheduler."
6968 #: build/C/man2/ioprio_set.2:225
6970 msgid "Selecting an I/O scheduler"
6974 #: build/C/man2/ioprio_set.2:229
6976 "I/O Schedulers are selected on a per-device basis via the special file "
6977 "I</sys/block/E<lt>deviceE<gt>/queue/scheduler>."
6981 #: build/C/man2/ioprio_set.2:235
6983 "One can view the current I/O scheduler via the I</sys> file system. For "
6984 "example, the following command displays a list of all schedulers currently "
6985 "loaded in the kernel:"
6989 #: build/C/man2/ioprio_set.2:240
6992 "$B< cat /sys/block/hda/queue/scheduler>\n"
6993 "noop anticipatory deadline [cfq]\n"
6997 #: build/C/man2/ioprio_set.2:254
6999 "The scheduler surrounded by brackets is the one actually in use for the "
7000 "device (I<hda> in the example). Setting another scheduler is done by "
7001 "writing the name of the new scheduler to this file. For example, the "
7002 "following command will set the scheduler for the I<hda> device to I<cfq>:"
7006 #: build/C/man2/ioprio_set.2:260
7011 "#B< echo cfq E<gt> /sys/block/hda/queue/scheduler>\n"
7015 #: build/C/man2/ioprio_set.2:262
7017 msgid "The Completely Fair Queuing (CFQ) I/O scheduler"
7021 #: build/C/man2/ioprio_set.2:268
7023 "Since v3 (aka CFQ Time Sliced) CFQ implements I/O nice levels similar to "
7024 "those of CPU scheduling. These nice levels are grouped in three scheduling "
7025 "classes each one containing one or more priority levels:"
7029 #: build/C/man2/ioprio_set.2:268
7031 msgid "B<IOPRIO_CLASS_RT> (1)"
7035 #: build/C/man2/ioprio_set.2:283
7037 "This is the real-time I/O class. This scheduling class is given higher "
7038 "priority than any other class: processes from this class are given first "
7039 "access to the disk every time. Thus this I/O class needs to be used with "
7040 "some care: one I/O real-time process can starve the entire system. Within "
7041 "the real-time class, there are 8 levels of class data (priority) that "
7042 "determine exactly how much time this process needs the disk for on each "
7043 "service. The highest real-time priority level is 0; the lowest is 7. In "
7044 "the future this might change to be more directly mappable to performance, by "
7045 "passing in a desired data rate instead."
7049 #: build/C/man2/ioprio_set.2:283
7051 msgid "B<IOPRIO_CLASS_BE> (2)"
7055 #: build/C/man2/ioprio_set.2:296
7057 "This is the best-effort scheduling class, which is the default for any "
7058 "process that hasn't set a specific I/O priority. The class data (priority) "
7059 "determines how much I/O bandwidth the process will get. Best-effort "
7060 "priority levels are analogous to CPU nice values (see B<getpriority>(2)). "
7061 "The priority level determines a priority relative to other processes in the "
7062 "best-effort scheduling class. Priority levels range from 0 (highest) to 7 "
7067 #: build/C/man2/ioprio_set.2:296
7069 msgid "B<IOPRIO_CLASS_IDLE> (3)"
7073 #: build/C/man2/ioprio_set.2:305
7075 "This is the idle scheduling class. Processes running at this level only get "
7076 "I/O time when no-one else needs the disk. The idle class has no class "
7077 "data. Attention is required when assigning this priority class to a "
7078 "process, since it may become starved if higher priority processes are "
7079 "constantly accessing the disk."
7083 #: build/C/man2/ioprio_set.2:309
7085 "Refer to I<Documentation/block/ioprio.txt> for more information on the CFQ "
7086 "I/O Scheduler and an example program."
7090 #: build/C/man2/ioprio_set.2:309
7092 msgid "Required permissions to set I/O priorities"
7096 #: build/C/man2/ioprio_set.2:312
7098 "Permission to change a process's priority is granted or denied based on two "
7103 #: build/C/man2/ioprio_set.2:312
7105 msgid "B<Process ownership>"
7109 #: build/C/man2/ioprio_set.2:320
7111 "An unprivileged process may only set the I/O priority of a process whose "
7112 "real UID matches the real or effective UID of the calling process. A "
7113 "process which has the B<CAP_SYS_NICE> capability can change the priority of "
7118 #: build/C/man2/ioprio_set.2:320
7120 msgid "B<What is the desired priority>"
7124 #: build/C/man2/ioprio_set.2:332
7126 "Attempts to set very high priorities (B<IOPRIO_CLASS_RT>) require the "
7127 "B<CAP_SYS_ADMIN> capability. Kernel versions up to 2.6.24 also required "
7128 "B<CAP_SYS_ADMIN> to set a very low priority (B<IOPRIO_CLASS_IDLE>), but "
7129 "since Linux 2.6.25, this is no longer required."
7133 #: build/C/man2/ioprio_set.2:337
7135 "A call to B<ioprio_set>() must follow both rules, or the call will fail "
7136 "with the error B<EPERM>."
7139 #. 6 May 07: Bug report raised:
7140 #. http://sources.redhat.com/bugzilla/show_bug.cgi?id=4464
7141 #. Ulrich Drepper replied that he wasn't going to add these
7144 #: build/C/man2/ioprio_set.2:346
7146 "Glibc does not yet provide a suitable header file defining the function "
7147 "prototypes and macros described on this page. Suitable definitions can be "
7148 "found in I<linux/ioprio.h>."
7152 #: build/C/man2/ioprio_set.2:351
7153 msgid "B<ionice>(1), B<getpriority>(2), B<open>(2), B<capabilities>(7)"
7157 #: build/C/man2/ioprio_set.2:354
7158 msgid "I<Documentation/block/ioprio.txt> in the Linux kernel source tree"
7162 #: build/C/man2/ipc.2:25
7168 #: build/C/man2/ipc.2:25
7174 #: build/C/man2/ipc.2:28
7175 msgid "ipc - System V IPC system calls"
7179 #: build/C/man2/ipc.2:33
7182 "B<int ipc(unsigned int >I<call>B<, int >I<first>B<, int >I<second>B<, int "
7184 "B< void *>I<ptr>B<, long >I<fifth>B<);>\n"
7188 #: build/C/man2/ipc.2:41
7190 "B<ipc>() is a common kernel entry point for the System V IPC calls for "
7191 "messages, semaphores, and shared memory. I<call> determines which IPC "
7192 "function to invoke; the other arguments are passed through to the "
7197 #: build/C/man2/ipc.2:45
7199 "User programs should call the appropriate functions by their usual names. "
7200 "Only standard library implementors and kernel hackers need to know about "
7205 #: build/C/man2/ipc.2:49
7207 "B<ipc>() is Linux-specific, and should not be used in programs intended to "
7212 #: build/C/man2/ipc.2:57
7214 "On some architectures\\(emfor example x86-64 and ARM\\(emthere is no "
7215 "B<ipc>() system call; instead B<msgctl>(2), B<semctl>(2), B<shmctl>(2), and "
7216 "so on really are implemented as separate system calls."
7220 #: build/C/man2/ipc.2:70
7222 "B<msgctl>(2), B<msgget>(2), B<msgrcv>(2), B<msgsnd>(2), B<semctl>(2), "
7223 "B<semget>(2), B<semop>(2), B<semtimedop>(2), B<shmat>(2), B<shmctl>(2), "
7224 "B<shmdt>(2), B<shmget>(2)"
7228 #: build/C/man2/seteuid.2:29
7234 #: build/C/man2/seteuid.2:29
7240 #: build/C/man2/seteuid.2:32
7241 msgid "seteuid, setegid - set effective user or group ID"
7245 #: build/C/man2/seteuid.2:38
7246 msgid "B<int seteuid(uid_t >I<euid>B<);>"
7250 #: build/C/man2/seteuid.2:40
7251 msgid "B<int setegid(gid_t >I<egid>B<);>"
7255 #: build/C/man2/seteuid.2:49
7256 msgid "B<seteuid>(), B<setegid>():"
7260 #: build/C/man2/seteuid.2:51
7262 "_BSD_SOURCE || _POSIX_C_SOURCE\\ E<gt>=\\ 200112L || _XOPEN_SOURCE\\ "
7267 #: build/C/man2/seteuid.2:58
7269 "B<seteuid>() sets the effective user ID of the calling process. "
7270 "Unprivileged user processes may only set the effective user ID to the real "
7271 "user ID, the effective user ID or the saved set-user-ID."
7276 #. equals \-1, nothing is changed.
7277 #. (This is an artifact of the implementation in glibc of seteuid()
7278 #. using setresuid(2).)
7280 #: build/C/man2/seteuid.2:67
7282 "Precisely the same holds for B<setegid>() with \"group\" instead of "
7287 #: build/C/man2/seteuid.2:91
7289 "The calling process is not privileged (Linux: does not have the "
7290 "B<CAP_SETUID> capability in the case of B<seteuid>(), or the B<CAP_SETGID> "
7291 "capability in the case of B<setegid>()) and I<euid> (respectively, I<egid>) "
7292 "is not the real user (group) ID, the effective user (group) ID, or the saved "
7293 "set-user-ID (saved set-group-ID)."
7297 #: build/C/man2/seteuid.2:93
7298 msgid "4.3BSD, POSIX.1-2001."
7302 #: build/C/man2/seteuid.2:99
7304 "Setting the effective user (group) ID to the saved set-user-ID (saved "
7305 "set-group-ID) is possible since Linux 1.1.37 (1.1.38). On an arbitrary "
7306 "system one should check B<_POSIX_SAVED_IDS>."
7310 #: build/C/man2/seteuid.2:115
7312 "Under libc4, libc5 and glibc 2.0 B<seteuid(>I<euid>B<)> is equivalent to "
7313 "B<setreuid(-1,>I< euid>B<)> and hence may change the saved set-user-ID. "
7314 "Under glibc 2.1 and later it is equivalent to B<setresuid(-1,>I< euid>B<, "
7315 "-1)> and hence does not change the saved set-user-ID. Analogous remarks "
7316 "hold for B<setegid>(), with the difference that the change in implementation "
7317 "from B<setregid(-1,>I< egid>B<)> to B<setresgid(-1,>I< egid>B<, -1)> "
7318 "occurred in glibc 2.2 or 2.3 (dependeing on the hardware architecture)."
7322 #: build/C/man2/seteuid.2:124
7324 "According to POSIX.1, B<seteuid>() (B<setegid>()) need not permit I<euid> "
7325 "(I<egid>) to be the same value as the current effective user (group) ID, "
7326 "and some implementations do not permit this."
7330 #: build/C/man2/seteuid.2:131
7332 "B<geteuid>(2), B<setresuid>(2), B<setreuid>(2), B<setuid>(2), "
7333 "B<capabilities>(7), B<credentials>(7)"
7337 #: build/C/man2/setfsgid.2:31
7343 #: build/C/man2/setfsgid.2:34
7344 msgid "setfsgid - set group identity used for file system checks"
7348 #: build/C/man2/setfsgid.2:37 build/C/man2/setfsuid.2:37
7349 msgid "B<#include E<lt>unistd.hE<gt>> /* glibc uses E<lt>sys/fsuid.hE<gt> */"
7353 #: build/C/man2/setfsgid.2:39
7354 msgid "B<int setfsgid(uid_t >I<fsgid>B<);>"
7358 #: build/C/man2/setfsgid.2:51
7360 "The system call B<setfsgid>() sets the group ID that the Linux kernel uses "
7361 "to check for all accesses to the file system. Normally, the value of "
7362 "I<fsgid> will shadow the value of the effective group ID. In fact, whenever "
7363 "the effective group ID is changed, I<fsgid> will also be changed to the new "
7364 "value of the effective group ID."
7368 #: build/C/man2/setfsgid.2:62
7370 "Explicit calls to B<setfsuid>(2) and B<setfsgid>() are usually only used "
7371 "by programs such as the Linux NFS server that need to change what user and "
7372 "group ID is used for file access without a corresponding change in the real "
7373 "and effective user and group IDs. A change in the normal user IDs for a "
7374 "program such as the NFS server is a security hole that can expose it to "
7375 "unwanted signals. (But see below.)"
7379 #: build/C/man2/setfsgid.2:69
7381 "B<setfsgid>() will only succeed if the caller is the superuser or if "
7382 "I<fsgid> matches either the real group ID, effective group ID, saved "
7383 "set-group-ID, or the current value of I<fsgid>."
7387 #: build/C/man2/setfsgid.2:76
7389 "On success, the previous value of I<fsgid> is returned. On error, the "
7390 "current value of I<fsgid> is returned."
7393 #. This system call is present since Linux 1.1.44
7394 #. and in libc since libc 4.7.6.
7396 #: build/C/man2/setfsgid.2:80 build/C/man2/setfsuid.2:80
7397 msgid "This system call is present in Linux since version 1.2."
7401 #: build/C/man2/setfsgid.2:84
7403 "B<setfsgid>() is Linux-specific and should not be used in programs intended "
7408 #: build/C/man2/setfsgid.2:90
7410 "When glibc determines that the argument is not a valid group ID, it will "
7411 "return -1 and set I<errno> to B<EINVAL> without attempting the system call."
7415 #: build/C/man2/setfsgid.2:94 build/C/man2/setfsuid.2:94
7417 "Note that at the time this system call was introduced, a process could send "
7418 "a signal to a process with the same effective user ID. Today signal "
7419 "permission handling is slightly different."
7423 #: build/C/man2/setfsgid.2:104
7425 "The original Linux B<setfsgid>() system call supported only 16-bit group "
7426 "IDs. Subsequently, Linux 2.4 added B<setfsgid32>() supporting 32-bit IDs. "
7427 "The glibc B<setfsgid>() wrapper function transparently deals with the "
7428 "variation across kernel versions."
7432 #: build/C/man2/setfsgid.2:112
7434 "No error messages of any kind are returned to the caller. At the very "
7435 "least, B<EPERM> should be returned when the call fails (because the caller "
7436 "lacks the B<CAP_SETGID> capability)."
7440 #: build/C/man2/setfsgid.2:117
7441 msgid "B<kill>(2), B<setfsuid>(2), B<capabilities>(7), B<credentials>(7)"
7445 #: build/C/man2/setfsuid.2:31
7451 #: build/C/man2/setfsuid.2:34
7452 msgid "setfsuid - set user identity used for file system checks"
7456 #: build/C/man2/setfsuid.2:39
7457 msgid "B<int setfsuid(uid_t >I<fsuid>B<);>"
7461 #: build/C/man2/setfsuid.2:51
7463 "The system call B<setfsuid>() sets the user ID that the Linux kernel uses "
7464 "to check for all accesses to the file system. Normally, the value of "
7465 "I<fsuid> will shadow the value of the effective user ID. In fact, whenever "
7466 "the effective user ID is changed, I<fsuid> will also be changed to the new "
7467 "value of the effective user ID."
7471 #: build/C/man2/setfsuid.2:62
7473 "Explicit calls to B<setfsuid>() and B<setfsgid>(2) are usually only used "
7474 "by programs such as the Linux NFS server that need to change what user and "
7475 "group ID is used for file access without a corresponding change in the real "
7476 "and effective user and group IDs. A change in the normal user IDs for a "
7477 "program such as the NFS server is a security hole that can expose it to "
7478 "unwanted signals. (But see below.)"
7482 #: build/C/man2/setfsuid.2:69
7484 "B<setfsuid>() will only succeed if the caller is the superuser or if "
7485 "I<fsuid> matches either the real user ID, effective user ID, saved "
7486 "set-user-ID, or the current value of I<fsuid>."
7490 #: build/C/man2/setfsuid.2:76
7492 "On success, the previous value of I<fsuid> is returned. On error, the "
7493 "current value of I<fsuid> is returned."
7497 #: build/C/man2/setfsuid.2:84
7499 "B<setfsuid>() is Linux-specific and should not be used in programs intended "
7504 #: build/C/man2/setfsuid.2:90
7506 "When glibc determines that the argument is not a valid user ID, it will "
7507 "return -1 and set I<errno> to B<EINVAL> without attempting the system call."
7511 #: build/C/man2/setfsuid.2:104
7513 "The original Linux B<setfsuid>() system call supported only 16-bit user "
7514 "IDs. Subsequently, Linux 2.4 added B<setfsuid32>() supporting 32-bit IDs. "
7515 "The glibc B<setfsuid>() wrapper function transparently deals with the "
7516 "variation across kernel versions."
7520 #: build/C/man2/setfsuid.2:112
7522 "No error messages of any kind are returned to the caller. At the very "
7523 "least, B<EPERM> should be returned when the call fails (because the caller "
7524 "lacks the B<CAP_SETUID> capability)."
7528 #: build/C/man2/setfsuid.2:117
7529 msgid "B<kill>(2), B<setfsgid>(2), B<capabilities>(7), B<credentials>(7)"
7533 #: build/C/man2/setgid.2:29
7539 #: build/C/man2/setgid.2:32
7540 msgid "setgid - set group identity"
7544 #: build/C/man2/setgid.2:38
7545 msgid "B<int setgid(gid_t >I<gid>B<);>"
7549 #: build/C/man2/setgid.2:43
7551 "B<setgid>() sets the effective group ID of the calling process. If the "
7552 "caller is the superuser, the real GID and saved set-group-ID are also set."
7556 #: build/C/man2/setgid.2:53
7558 "Under Linux, B<setgid>() is implemented like the POSIX version with the "
7559 "B<_POSIX_SAVED_IDS> feature. This allows a set-group-ID program that is not "
7560 "set-user-ID-root to drop all of its group privileges, do some un-privileged "
7561 "work, and then reengage the original effective group ID in a secure manner."
7565 #: build/C/man2/setgid.2:66
7567 "The calling process is not privileged (does not have the B<CAP_SETGID> "
7568 "capability), and I<gid> does not match the real group ID or saved "
7569 "set-group-ID of the calling process."
7573 #: build/C/man2/setgid.2:78
7575 "The original Linux B<setgid>() system call supported only 16-bit group "
7576 "IDs. Subsequently, Linux 2.4 added B<setgid32>() supporting 32-bit IDs. "
7577 "The glibc B<setgid>() wrapper function transparently deals with the "
7578 "variation across kernel versions."
7582 #: build/C/man2/setgid.2:84
7584 "B<getgid>(2), B<setegid>(2), B<setregid>(2), B<capabilities>(7), "
7589 #: build/C/man2/setpgid.2:48
7595 #: build/C/man2/setpgid.2:51
7596 msgid "setpgid, getpgid, setpgrp, getpgrp - set/get process group"
7600 #: build/C/man2/setpgid.2:55
7601 msgid "B<int setpgid(pid_t >I<pid>B<, pid_t >I<pgid>B<);>"
7605 #: build/C/man2/setpgid.2:57
7606 msgid "B<pid_t getpgid(pid_t >I<pid>B<);>"
7610 #: build/C/man2/setpgid.2:59
7611 msgid "B<pid_t getpgrp(void);> /* POSIX.1 version */"
7615 #: build/C/man2/setpgid.2:62
7617 "B<pid_t getpgrp(pid_t >I<pid>B<);\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ > /* BSD "
7622 #: build/C/man2/setpgid.2:64
7623 msgid "B<int setpgrp(void);> /* System V version */"
7627 #: build/C/man2/setpgid.2:67
7628 msgid "B<int setpgrp(pid_t >I<pid>B<, pid_t >I<pgid>B<);\\ > /* BSD version */"
7632 #: build/C/man2/setpgid.2:76
7633 msgid "B<getpgid>():"
7637 #: build/C/man2/setpgid.2:84
7638 msgid "B<setpgrp>() (POSIX.1):"
7642 #: build/C/man2/setpgid.2:87
7645 " _SVID_SOURCE || _XOPEN_SOURCE\\ E<gt>=\\ 500 ||\n"
7646 " _XOPEN_SOURCE\\ &&\\ _XOPEN_SOURCE_EXTENDED\n"
7650 #: build/C/man2/setpgid.2:91
7651 msgid "B<setpgrp>()\\ (BSD), B<getpgrp>()\\ (BSD):"
7655 #: build/C/man2/setpgid.2:95
7659 " !\\ (_POSIX_SOURCE || _POSIX_C_SOURCE || _XOPEN_SOURCE ||\n"
7660 " _XOPEN_SOURCE_EXTENDED || _GNU_SOURCE || _SVID_SOURCE)\n"
7664 #: build/C/man2/setpgid.2:107
7666 "All of these interfaces are available on Linux, and are used for getting and "
7667 "setting the process group ID (PGID) of a process. The preferred, "
7668 "POSIX.1-specified ways of doing this are: B<getpgrp>(void), for retrieving "
7669 "the calling process's PGID; and B<setpgid>(), for setting a process's PGID."
7673 #: build/C/man2/setpgid.2:132
7675 "B<setpgid>() sets the PGID of the process specified by I<pid> to I<pgid>. "
7676 "If I<pid> is zero, then the process ID of the calling process is used. If "
7677 "I<pgid> is zero, then the PGID of the process specified by I<pid> is made "
7678 "the same as its process ID. If B<setpgid>() is used to move a process from "
7679 "one process group to another (as is done by some shells when creating "
7680 "pipelines), both process groups must be part of the same session (see "
7681 "B<setsid>(2) and B<credentials>(7)). In this case, the I<pgid> specifies "
7682 "an existing process group to be joined and the session ID of that group must "
7683 "match the session ID of the joining process."
7687 #: build/C/man2/setpgid.2:137
7689 "The POSIX.1 version of B<getpgrp>(), which takes no arguments, returns the "
7690 "PGID of the calling process."
7694 #: build/C/man2/setpgid.2:148
7696 "B<getpgid>() returns the PGID of the process specified by I<pid>. If "
7697 "I<pid> is zero, the process ID of the calling process is used. (Retrieving "
7698 "the PGID of a process other than the caller is rarely necessary, and the "
7699 "POSIX.1 B<getpgrp>() is preferred for that task.)"
7703 #: build/C/man2/setpgid.2:153
7705 "The System V-style B<setpgrp>(), which takes no arguments, is equivalent to "
7706 "I<setpgid(0,\\ 0)>."
7709 #. The true BSD setpgrp() system call differs in allowing the PGID
7710 #. to be set to arbitrary values, rather than being restricted to
7711 #. PGIDs in the same session.
7713 #: build/C/man2/setpgid.2:165
7715 "The BSD-specific B<setpgrp>() call, which takes arguments I<pid> and "
7716 "I<pgid>, is equivalent to I<setpgid(pid, pgid)>."
7720 #: build/C/man2/setpgid.2:172
7722 "The BSD-specific B<getpgrp>() call, which takes a single I<pid> argument, "
7723 "is equivalent to I<getpgid(pid)>."
7727 #: build/C/man2/setpgid.2:181
7729 "On success, B<setpgid>() and B<setpgrp>() return zero. On error, -1 is "
7730 "returned, and I<errno> is set appropriately."
7734 #: build/C/man2/setpgid.2:185
7735 msgid "The POSIX.1 B<getpgrp>() always returns the PGID of the caller."
7739 #: build/C/man2/setpgid.2:193
7741 "B<getpgid>(), and the BSD-specific B<getpgrp>() return a process group on "
7742 "success. On error, -1 is returned, and I<errno> is set appropriately."
7746 #: build/C/man2/setpgid.2:202
7748 "An attempt was made to change the process group ID of one of the children of "
7749 "the calling process and the child had already performed an B<execve>(2) "
7750 "(B<setpgid>(), B<setpgrp>())."
7754 #: build/C/man2/setpgid.2:208
7755 msgid "I<pgid> is less than 0 (B<setpgid>(), B<setpgrp>())."
7759 #: build/C/man2/setpgid.2:217
7761 "An attempt was made to move a process into a process group in a different "
7762 "session, or to change the process group ID of one of the children of the "
7763 "calling process and the child was in a different session, or to change the "
7764 "process group ID of a session leader (B<setpgid>(), B<setpgrp>())."
7768 #: build/C/man2/setpgid.2:227
7770 "For B<getpgid>(): I<pid> does not match any process. For B<setpgid>(): "
7771 "I<pid> is not the calling process and not a child of the calling process."
7775 #: build/C/man2/setpgid.2:233
7777 "B<setpgid>() and the version of B<getpgrp>() with no arguments conform to "
7782 #: build/C/man2/setpgid.2:242
7784 "POSIX.1-2001 also specifies B<getpgid>() and the version of B<setpgrp>() "
7785 "that takes no arguments. (POSIX.1-2008 marks this B<setpgrp>() "
7786 "specification as obsolete.)"
7790 #: build/C/man2/setpgid.2:249
7792 "The version of B<getpgrp>() with one argument and the version of "
7793 "B<setpgrp>() that takes two arguments derive from 4.2BSD, and are not "
7794 "specified by POSIX.1."
7798 #: build/C/man2/setpgid.2:255
7800 "A child created via B<fork>(2) inherits its parent's process group ID. The "
7801 "PGID is preserved across an B<execve>(2)."
7805 #: build/C/man2/setpgid.2:258
7807 "Each process group is a member of a session and each process is a member of "
7808 "the session of which its process group is a member."
7812 #: build/C/man2/setpgid.2:285
7814 "A session can have a controlling terminal. At any time, one (and only one) "
7815 "of the process groups in the session can be the foreground process group for "
7816 "the terminal; the remaining process groups are in the background. If a "
7817 "signal is generated from the terminal (e.g., typing the interrupt key to "
7818 "generate B<SIGINT>), that signal is sent to the foreground process group. "
7819 "(See B<termios>(3) for a description of the characters that generate "
7820 "signals.) Only the foreground process group may B<read>(2) from the "
7821 "terminal; if a background process group tries to B<read>(2) from the "
7822 "terminal, then the group is sent a B<SIGTSTP> signal, which suspends it. "
7823 "The B<tcgetpgrp>(3) and B<tcsetpgrp>(3) functions are used to get/set the "
7824 "foreground process group of the controlling terminal."
7828 #: build/C/man2/setpgid.2:293
7830 "The B<setpgid>() and B<getpgrp>() calls are used by programs such as "
7831 "B<bash>(1) to create process groups in order to implement shell job "
7836 #: build/C/man2/setpgid.2:303
7838 "If a session has a controlling terminal, and the B<CLOCAL> flag for that "
7839 "terminal is not set, and a terminal hangup occurs, then the session leader "
7840 "is sent a B<SIGHUP>. If the session leader exits, then a B<SIGHUP> signal "
7841 "will also be sent to each process in the foreground process group of the "
7842 "controlling terminal."
7845 #. exit.3 refers to the following text:
7847 #: build/C/man2/setpgid.2:317
7849 "If the exit of the process causes a process group to become orphaned, and if "
7850 "any member of the newly orphaned process group is stopped, then a B<SIGHUP> "
7851 "signal followed by a B<SIGCONT> signal will be sent to each process in the "
7852 "newly orphaned process group. An orphaned process group is one in which the "
7853 "parent of every member of process group is either itself also a member of "
7854 "the process group or is a member of a process group in a different session "
7855 "(see also B<credentials>(7))."
7859 #: build/C/man2/setpgid.2:324
7861 "B<getuid>(2), B<setsid>(2), B<tcgetpgrp>(3), B<tcsetpgrp>(3), B<termios>(3), "
7866 #: build/C/man2/setresuid.2:26
7872 #: build/C/man2/setresuid.2:29
7873 msgid "setresuid, setresgid - set real, effective and saved user or group ID"
7877 #: build/C/man2/setresuid.2:35
7878 msgid "B<int setresuid(uid_t >I<ruid>B<, uid_t >I<euid>B<, uid_t >I<suid>B<);>"
7882 #: build/C/man2/setresuid.2:37
7883 msgid "B<int setresgid(gid_t >I<rgid>B<, gid_t >I<egid>B<, gid_t >I<sgid>B<);>"
7887 #: build/C/man2/setresuid.2:41
7889 "B<setresuid>() sets the real user ID, the effective user ID, and the saved "
7890 "set-user-ID of the calling process."
7894 #: build/C/man2/setresuid.2:47
7896 "Unprivileged user processes may change the real UID, effective UID, and "
7897 "saved set-user-ID, each to one of: the current real UID, the current "
7898 "effective UID or the current saved set-user-ID."
7902 #: build/C/man2/setresuid.2:51
7904 "Privileged processes (on Linux, those having the B<CAP_SETUID> capability) "
7905 "may set the real UID, effective UID, and saved set-user-ID to arbitrary "
7910 #: build/C/man2/setresuid.2:53
7911 msgid "If one of the arguments equals -1, the corresponding value is not changed."
7915 #: build/C/man2/setresuid.2:57
7917 "Regardless of what changes are made to the real UID, effective UID, and "
7918 "saved set-user-ID, the file system UID is always set to the same value as "
7919 "the (possibly new) effective UID."
7923 #: build/C/man2/setresuid.2:64
7925 "Completely analogously, B<setresgid>() sets the real GID, effective GID, "
7926 "and saved set-group-ID of the calling process (and always modifies the file "
7927 "system GID to be the same as the effective GID), with the same restrictions "
7928 "for unprivileged processes."
7932 #: build/C/man2/setresuid.2:70 build/C/man2/setuid.2:76
7938 #: build/C/man2/setresuid.2:77
7940 "I<uid> does not match the current UID and this call would bring that user ID "
7941 "over its B<RLIMIT_NPROC> resource limit."
7945 #: build/C/man2/setresuid.2:81
7947 "The calling process is not privileged (did not have the B<CAP_SETUID> "
7948 "capability) and tried to change the IDs to values that are not permitted."
7952 #: build/C/man2/setresuid.2:83
7953 msgid "These calls are available under Linux since Linux 2.1.44."
7957 #: build/C/man2/setresuid.2:90
7959 "Under HP-UX and FreeBSD, the prototype is found in I<E<lt>unistd.hE<gt>>. "
7960 "Under Linux the prototype is provided by glibc since version 2.3.2."
7964 #: build/C/man2/setresuid.2:106
7966 "The original Linux B<setresuid>() and B<setresgid>() system calls "
7967 "supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added "
7968 "B<setresuid32>() and B<setresgid32>(), supporting 32-bit IDs. The glibc "
7969 "B<setresuid>() and B<setresgid>() wrapper functions transparently deal "
7970 "with the variations across kernel versions."
7974 #: build/C/man2/setresuid.2:115
7976 "B<getresuid>(2), B<getuid>(2), B<setfsgid>(2), B<setfsuid>(2), "
7977 "B<setreuid>(2), B<setuid>(2), B<capabilities>(7), B<credentials>(7)"
7981 #: build/C/man2/setreuid.2:45
7987 #: build/C/man2/setreuid.2:48
7988 msgid "setreuid, setregid - set real and/or effective user or group ID"
7992 #: build/C/man2/setreuid.2:54
7993 msgid "B<int setreuid(uid_t >I<ruid>B<, uid_t >I<euid>B<);>"
7997 #: build/C/man2/setreuid.2:56
7998 msgid "B<int setregid(gid_t >I<rgid>B<, gid_t >I<egid>B<);>"
8002 #: build/C/man2/setreuid.2:64
8003 msgid "B<setreuid>(), B<setregid>():"
8007 #: build/C/man2/setreuid.2:68
8009 "_BSD_SOURCE || _XOPEN_SOURCE\\ E<gt>=\\ 500 || _XOPEN_SOURCE\\ &&\\ "
8010 "_XOPEN_SOURCE_EXTENDED"
8014 #: build/C/man2/setreuid.2:73
8015 msgid "B<setreuid>() sets real and effective user IDs of the calling process."
8019 #: build/C/man2/setreuid.2:76
8021 "Supplying a value of -1 for either the real or effective user ID forces the "
8022 "system to leave that ID unchanged."
8026 #: build/C/man2/setreuid.2:79
8028 "Unprivileged processes may only set the effective user ID to the real user "
8029 "ID, the effective user ID, or the saved set-user-ID."
8033 #: build/C/man2/setreuid.2:82
8035 "Unprivileged users may only set the real user ID to the real user ID or the "
8036 "effective user ID."
8040 #: build/C/man2/setreuid.2:86
8042 "If the real user ID is set or the effective user ID is set to a value not "
8043 "equal to the previous real user ID, the saved set-user-ID will be set to the "
8044 "new effective user ID."
8048 #: build/C/man2/setreuid.2:91
8050 "Completely analogously, B<setregid>() sets real and effective group ID's of "
8051 "the calling process, and all of the above holds with \"group\" instead of "
8056 #: build/C/man2/setreuid.2:113
8058 "The calling process is not privileged (Linux: does not have the "
8059 "B<CAP_SETUID> capability in the case of B<setreuid>(), or the B<CAP_SETGID> "
8060 "capability in the case of B<setregid>()) and a change other than (i) "
8061 "swapping the effective user (group) ID with the real user (group) ID, or "
8062 "(ii) setting one to the value of the other or (iii) setting the effective "
8063 "user (group) ID to the value of the saved set-user-ID (saved set-group-ID) "
8068 #: build/C/man2/setreuid.2:119
8070 "POSIX.1-2001, 4.3BSD (the B<setreuid>() and B<setregid>() function calls "
8071 "first appeared in 4.2BSD)."
8075 #: build/C/man2/setreuid.2:123
8077 "Setting the effective user (group) ID to the saved set-user-ID (saved "
8078 "set-group-ID) is possible since Linux 1.1.37 (1.1.38)."
8082 #: build/C/man2/setreuid.2:140
8084 "POSIX.1 does not specify all of possible ID changes that are permitted on "
8085 "Linux for an unprivileged process. For B<setreuid>(), the effective user ID "
8086 "can be made the same as the real user ID or the save set-user-ID, and it is "
8087 "unspecified whether unprivileged processes may set the real user ID to the "
8088 "real user ID, the effective user ID, or the saved set-user-ID. For "
8089 "B<setregid>(), the real group ID can be changed to the value of the saved "
8090 "set-group-ID, and the effective group ID can be changed to the value of the "
8091 "real group ID or the saved set-group-ID. The precise details of what ID "
8092 "changes are permitted vary across implementations."
8096 #: build/C/man2/setreuid.2:143
8098 "POSIX.1 makes no specification about the effect of these calls on the saved "
8099 "set-user-ID and saved set-group-ID."
8103 #: build/C/man2/setreuid.2:159
8105 "The original Linux B<setreuid>() and B<setregid>() system calls supported "
8106 "only 16-bit user and group IDs. Subsequently, Linux 2.4 added "
8107 "B<setreuid32>() and B<setregid32>(), supporting 32-bit IDs. The glibc "
8108 "B<setreuid>() and B<setregid>() wrapper functions transparently deal with "
8109 "the variations across kernel versions."
8113 #: build/C/man2/setreuid.2:167
8115 "B<getgid>(2), B<getuid>(2), B<seteuid>(2), B<setgid>(2), B<setresuid>(2), "
8116 "B<setuid>(2), B<capabilities>(7)"
8120 #: build/C/man2/setsid.2:30
8126 #: build/C/man2/setsid.2:33
8127 msgid "setsid - creates a session and sets the process group ID"
8131 #: build/C/man2/setsid.2:38
8132 msgid "B<pid_t setsid(void);>"
8136 #: build/C/man2/setsid.2:51
8138 "B<setsid>() creates a new session if the calling process is not a process "
8139 "group leader. The calling process is the leader of the new session, the "
8140 "process group leader of the new process group, and has no controlling "
8141 "terminal. The process group ID and session ID of the calling process are "
8142 "set to the PID of the calling process. The calling process will be the only "
8143 "process in this new process group and in this new session."
8147 #: build/C/man2/setsid.2:58
8149 "On success, the (new) session ID of the calling process is returned. On "
8150 "error, I<(pid_t)\\ -1> is returned, and I<errno> is set to indicate the "
8155 #: build/C/man2/setsid.2:65
8157 "The process group ID of any process equals the PID of the calling process. "
8158 "Thus, in particular, B<setsid>() fails if the calling process is already a "
8159 "process group leader."
8163 #: build/C/man2/setsid.2:73
8165 "A child created via B<fork>(2) inherits its parent's session ID. The "
8166 "session ID is preserved across an B<execve>(2)."
8170 #: build/C/man2/setsid.2:84
8172 "A process group leader is a process with process group ID equal to its PID. "
8173 "In order to be sure that B<setsid>() will succeed, B<fork>(2) and "
8174 "B<_exit>(2), and have the child do B<setsid>()."
8178 #: build/C/man2/setsid.2:91
8180 "B<setsid>(1), B<getsid>(2), B<setpgid>(2), B<setpgrp>(2), B<tcgetsid>(3), "
8185 #: build/C/man2/setuid.2:30
8191 #: build/C/man2/setuid.2:33
8192 msgid "setuid - set user identity"
8196 #: build/C/man2/setuid.2:39
8197 msgid "B<int setuid(uid_t >I<uid>B<);>"
8201 #: build/C/man2/setuid.2:44
8203 "B<setuid>() sets the effective user ID of the calling process. If the "
8204 "effective UID of the caller is root, the real UID and saved set-user-ID are "
8209 #: build/C/man2/setuid.2:53
8211 "Under Linux, B<setuid>() is implemented like the POSIX version with the "
8212 "B<_POSIX_SAVED_IDS> feature. This allows a set-user-ID (other than root) "
8213 "program to drop all of its user privileges, do some un-privileged work, and "
8214 "then reengage the original effective user ID in a secure manner."
8218 #: build/C/man2/setuid.2:63
8220 "If the user is root or the program is set-user-ID-root, special care must be "
8221 "taken. The B<setuid>() function checks the effective user ID of the caller "
8222 "and if it is the superuser, all process-related user ID's are set to "
8223 "I<uid>. After this has occurred, it is impossible for the program to regain "
8228 #: build/C/man2/setuid.2:70
8230 "Thus, a set-user-ID-root program wishing to temporarily drop root "
8231 "privileges, assume the identity of an unprivileged user, and then regain "
8232 "root privileges afterward cannot use B<setuid>(). You can accomplish this "
8233 "with B<seteuid>(2)."
8237 #: build/C/man2/setuid.2:85
8239 "The I<uid> does not match the current uid and I<uid> brings process over its "
8240 "B<RLIMIT_NPROC> resource limit."
8244 #: build/C/man2/setuid.2:92
8246 "The user is not privileged (Linux: does not have the B<CAP_SETUID> "
8247 "capability) and I<uid> does not match the real UID or saved set-user-ID of "
8248 "the calling process."
8251 #. SVr4 documents an additional EINVAL error condition.
8253 #: build/C/man2/setuid.2:97
8255 "SVr4, POSIX.1-2001. Not quite compatible with the 4.4BSD call, which sets "
8256 "all of the real, saved, and effective user IDs."
8260 #: build/C/man2/setuid.2:105
8262 "Linux has the concept of the file system user ID, normally equal to the "
8263 "effective user ID. The B<setuid>() call also sets the file system user ID "
8264 "of the calling process. See B<setfsuid>(2)."
8268 #: build/C/man2/setuid.2:110
8270 "If I<uid> is different from the old effective UID, the process will be "
8271 "forbidden from leaving core dumps."
8275 #: build/C/man2/setuid.2:120
8277 "The original Linux B<setuid>() system call supported only 16-bit user IDs. "
8278 "Subsequently, Linux 2.4 added B<setuid32>() supporting 32-bit IDs. The "
8279 "glibc B<setuid>() wrapper function transparently deals with the variation "
8280 "across kernel versions."
8284 #: build/C/man2/setuid.2:127
8286 "B<getuid>(2), B<seteuid>(2), B<setfsuid>(2), B<setreuid>(2), "
8287 "B<capabilities>(7), B<credentials>(7)"
8291 #: build/C/man7/svipc.7:27
8297 #: build/C/man7/svipc.7:30
8298 msgid "svipc - System V interprocess communication mechanisms"
8302 #: build/C/man7/svipc.7:35
8305 "B<#include E<lt>sys/msg.hE<gt>>\n"
8306 "B<#include E<lt>sys/sem.hE<gt>>\n"
8307 "B<#include E<lt>sys/shm.hE<gt>>\n"
8311 #: build/C/man7/svipc.7:43
8313 "This manual page refers to the Linux implementation of the System V "
8314 "interprocess communication (IPC) mechanisms: message queues, semaphore sets, "
8315 "and shared memory segments. In the following, the word I<resource> means an "
8316 "instantiation of one among such mechanisms."
8320 #: build/C/man7/svipc.7:43
8322 msgid "Resource access permissions"
8326 #: build/C/man7/svipc.7:51
8328 "For each resource, the system uses a common structure of type I<struct "
8329 "ipc_perm> to store information needed in determining permissions to perform "
8330 "an IPC operation. The I<ipc_perm> structure includes the following members:"
8334 #: build/C/man7/svipc.7:61
8337 "struct ipc_perm {\n"
8338 " uid_t cuid; /* creator user ID */\n"
8339 " gid_t cgid; /* creator group ID */\n"
8340 " uid_t uid; /* owner user ID */\n"
8341 " gid_t gid; /* owner group ID */\n"
8342 " unsigned short mode; /* r/w permissions */\n"
8347 #: build/C/man7/svipc.7:71
8349 "The I<mode> member of the I<ipc_perm> structure defines, with its lower 9 "
8350 "bits, the access permissions to the resource for a process executing an IPC "
8351 "system call. The permissions are interpreted as follows:"
8355 #: build/C/man7/svipc.7:75
8358 " 0400 Read by user.\n"
8359 " 0200 Write by user.\n"
8363 #: build/C/man7/svipc.7:78
8366 " 0040 Read by group.\n"
8367 " 0020 Write by group.\n"
8371 #: build/C/man7/svipc.7:81
8374 " 0004 Read by others.\n"
8375 " 0002 Write by others.\n"
8379 #: build/C/man7/svipc.7:89
8381 "Bits 0100, 0010, and 0001 (the execute bits) are unused by the system. "
8382 "Furthermore, \"write\" effectively means \"alter\" for a semaphore set."
8386 #: build/C/man7/svipc.7:92
8387 msgid "The same system header file also defines the following symbolic constants:"
8391 #: build/C/man7/svipc.7:92
8393 msgid "B<IPC_CREAT>"
8397 #: build/C/man7/svipc.7:95
8398 msgid "Create entry if key doesn't exist."
8402 #: build/C/man7/svipc.7:95
8408 #: build/C/man7/svipc.7:98
8409 msgid "Fail if key exists."
8413 #: build/C/man7/svipc.7:98
8415 msgid "B<IPC_NOWAIT>"
8419 #: build/C/man7/svipc.7:101
8420 msgid "Error if request must wait."
8424 #: build/C/man7/svipc.7:101
8426 msgid "B<IPC_PRIVATE>"
8430 #: build/C/man7/svipc.7:104
8431 msgid "Private key."
8435 #: build/C/man7/svipc.7:104
8441 #: build/C/man7/svipc.7:107
8442 msgid "Remove resource."
8446 #: build/C/man7/svipc.7:107
8452 #: build/C/man7/svipc.7:110
8453 msgid "Set resource options."
8457 #: build/C/man7/svipc.7:110
8463 #: build/C/man7/svipc.7:113
8464 msgid "Get resource options."
8468 #: build/C/man7/svipc.7:122
8470 "Note that B<IPC_PRIVATE> is a I<key_t> type, while all the other symbolic "
8471 "constants are flag fields and can be OR'ed into an I<int> type variable."
8475 #: build/C/man7/svipc.7:122
8477 msgid "Message queues"
8481 #: build/C/man7/svipc.7:130
8483 "A message queue is uniquely identified by a positive integer (its I<msqid>) "
8484 "and has an associated data structure of type I<struct msqid_ds>, defined in "
8485 "I<E<lt>sys/msg.hE<gt>>, containing the following members:"
8489 #: build/C/man7/svipc.7:143
8492 "struct msqid_ds {\n"
8493 " struct ipc_perm msg_perm;\n"
8494 " msgqnum_t msg_qnum; /* no of messages on queue */\n"
8495 " msglen_t msg_qbytes; /* bytes max on a queue */\n"
8496 " pid_t msg_lspid; /* PID of last msgsnd(2) call */\n"
8497 " pid_t msg_lrpid; /* PID of last msgrcv(2) call */\n"
8498 " time_t msg_stime; /* last msgsnd(2) time */\n"
8499 " time_t msg_rtime; /* last msgrcv(2) time */\n"
8500 " time_t msg_ctime; /* last change time */\n"
8505 #: build/C/man7/svipc.7:145
8511 #: build/C/man7/svipc.7:150
8513 "I<ipc_perm> structure that specifies the access permissions on the message "
8518 #: build/C/man7/svipc.7:150
8524 #: build/C/man7/svipc.7:153
8525 msgid "Number of messages currently on the message queue."
8529 #: build/C/man7/svipc.7:153
8531 msgid "I<msg_qbytes>"
8535 #: build/C/man7/svipc.7:157
8536 msgid "Maximum number of bytes of message text allowed on the message queue."
8540 #: build/C/man7/svipc.7:157
8542 msgid "I<msg_lspid>"
8546 #: build/C/man7/svipc.7:162
8547 msgid "ID of the process that performed the last B<msgsnd>(2) system call."
8551 #: build/C/man7/svipc.7:162
8553 msgid "I<msg_lrpid>"
8557 #: build/C/man7/svipc.7:167
8558 msgid "ID of the process that performed the last B<msgrcv>(2) system call."
8562 #: build/C/man7/svipc.7:167
8564 msgid "I<msg_stime>"
8568 #: build/C/man7/svipc.7:172
8569 msgid "Time of the last B<msgsnd>(2) system call."
8573 #: build/C/man7/svipc.7:172
8575 msgid "I<msg_rtime>"
8579 #: build/C/man7/svipc.7:177
8580 msgid "Time of the last B<msgrcv>(2) system call."
8584 #: build/C/man7/svipc.7:177
8586 msgid "I<msg_ctime>"
8590 #: build/C/man7/svipc.7:183
8592 "Time of the last system call that changed a member of the I<msqid_ds> "
8597 #: build/C/man7/svipc.7:183
8599 msgid "Semaphore sets"
8603 #: build/C/man7/svipc.7:191
8605 "A semaphore set is uniquely identified by a positive integer (its I<semid>) "
8606 "and has an associated data structure of type I<struct semid_ds>, defined in "
8607 "I<E<lt>sys/sem.hE<gt>>, containing the following members:"
8611 #: build/C/man7/svipc.7:200
8614 "struct semid_ds {\n"
8615 " struct ipc_perm sem_perm;\n"
8616 " time_t sem_otime; /* last operation time */\n"
8617 " time_t sem_ctime; /* last change time */\n"
8618 " unsigned long sem_nsems; /* count of sems in set */\n"
8623 #: build/C/man7/svipc.7:202
8629 #: build/C/man7/svipc.7:207
8631 "I<ipc_perm> structure that specifies the access permissions on the semaphore "
8636 #: build/C/man7/svipc.7:207
8638 msgid "I<sem_otime>"
8642 #: build/C/man7/svipc.7:212
8643 msgid "Time of last B<semop>(2) system call."
8647 #: build/C/man7/svipc.7:212
8649 msgid "I<sem_ctime>"
8653 #: build/C/man7/svipc.7:218
8655 "Time of last B<semctl>(2) system call that changed a member of the above "
8656 "structure or of one semaphore belonging to the set."
8660 #: build/C/man7/svipc.7:218
8662 msgid "I<sem_nsems>"
8666 #: build/C/man7/svipc.7:226
8668 "Number of semaphores in the set. Each semaphore of the set is referenced by "
8669 "a nonnegative integer ranging from B<0> to I<sem_nsems-1>."
8673 #: build/C/man7/svipc.7:230
8675 "A semaphore is a data structure of type I<struct sem> containing the "
8676 "following members:"
8679 #. unsigned short semncnt; /* nr awaiting semval to increase */
8680 #. unsigned short semzcnt; /* nr awaiting semval = 0 */
8682 #: build/C/man7/svipc.7:239
8686 " int semval; /* semaphore value */\n"
8687 " int sempid; /* PID for last operation */\n"
8692 #: build/C/man7/svipc.7:241
8698 #: build/C/man7/svipc.7:244
8699 msgid "Semaphore value: a nonnegative integer."
8703 #: build/C/man7/svipc.7:244
8710 #. Number of processes suspended awaiting for
8715 #. Number of processes suspended awaiting for
8719 #: build/C/man7/svipc.7:258
8721 "ID of the last process that performed a semaphore operation on this "
8726 #: build/C/man7/svipc.7:258
8728 msgid "Shared memory segments"
8732 #: build/C/man7/svipc.7:266
8734 "A shared memory segment is uniquely identified by a positive integer (its "
8735 "I<shmid>) and has an associated data structure of type I<struct shmid_ds>, "
8736 "defined in I<E<lt>sys/shm.hE<gt>>, containing the following members:"
8740 #: build/C/man7/svipc.7:279
8743 "struct shmid_ds {\n"
8744 " struct ipc_perm shm_perm;\n"
8745 " size_t shm_segsz; /* size of segment */\n"
8746 " pid_t shm_cpid; /* PID of creator */\n"
8747 " pid_t shm_lpid; /* PID, last operation */\n"
8748 " shmatt_t shm_nattch; /* no. of current attaches */\n"
8749 " time_t shm_atime; /* time of last attach */\n"
8750 " time_t shm_dtime; /* time of last detach */\n"
8751 " time_t shm_ctime; /* time of last change */\n"
8756 #: build/C/man7/svipc.7:281
8762 #: build/C/man7/svipc.7:286
8764 "I<ipc_perm> structure that specifies the access permissions on the shared "
8769 #: build/C/man7/svipc.7:286
8771 msgid "I<shm_segsz>"
8775 #: build/C/man7/svipc.7:289
8776 msgid "Size in bytes of the shared memory segment."
8780 #: build/C/man7/svipc.7:289
8786 #: build/C/man7/svipc.7:292
8787 msgid "ID of the process that created the shared memory segment."
8791 #: build/C/man7/svipc.7:292
8797 #: build/C/man7/svipc.7:299
8799 "ID of the last process that executed a B<shmat>(2) or B<shmdt>(2) system "
8804 #: build/C/man7/svipc.7:299
8806 msgid "I<shm_nattch>"
8810 #: build/C/man7/svipc.7:302
8811 msgid "Number of current alive attaches for this shared memory segment."
8815 #: build/C/man7/svipc.7:302
8817 msgid "I<shm_atime>"
8821 #: build/C/man7/svipc.7:307
8822 msgid "Time of the last B<shmat>(2) system call."
8826 #: build/C/man7/svipc.7:307
8828 msgid "I<shm_dtime>"
8832 #: build/C/man7/svipc.7:312
8833 msgid "Time of the last B<shmdt>(2) system call."
8837 #: build/C/man7/svipc.7:312
8839 msgid "I<shm_ctime>"
8843 #: build/C/man7/svipc.7:318
8844 msgid "Time of the last B<shmctl>(2) system call that changed I<shmid_ds>."
8848 #: build/C/man7/svipc.7:335
8850 "B<ipcmk>(1), B<ipcrm>(1), B<ipcs>(1), B<ipc>(2), B<msgctl>(2), B<msgget>(2), "
8851 "B<msgrcv>(2), B<msgsnd>(2), B<semctl>(2), B<semget>(2), B<semop>(2), "
8852 "B<shmat>(2), B<shmctl>(2), B<shmdt>(2), B<shmget>(2), B<ftok>(3)"
8856 #: build/C/man3/ulimit.3:27
8862 #: build/C/man3/ulimit.3:27
8868 #: build/C/man3/ulimit.3:30
8869 msgid "ulimit - get and set user limits"
8873 #: build/C/man3/ulimit.3:32
8874 msgid "B<#include E<lt>ulimit.hE<gt>>"
8878 #: build/C/man3/ulimit.3:34
8879 msgid "B<long ulimit(int >I<cmd>B<, long >I<newlimit>B<);>"
8883 #: build/C/man3/ulimit.3:46
8885 "Warning: This routine is obsolete. Use B<getrlimit>(2), B<setrlimit>(2), "
8886 "and B<sysconf>(3) instead. For the shell command B<ulimit>(), see "
8891 #: build/C/man3/ulimit.3:53
8893 "The B<ulimit>() call will get or set some limit for the calling process. "
8894 "The I<cmd> argument can have one of the following values."
8898 #: build/C/man3/ulimit.3:53
8900 msgid "B<UL_GETFSIZE>"
8904 #: build/C/man3/ulimit.3:56
8905 msgid "Return the limit on the size of a file, in units of 512 bytes."
8909 #: build/C/man3/ulimit.3:56
8911 msgid "B<UL_SETFSIZE>"
8915 #: build/C/man3/ulimit.3:59
8916 msgid "Set the limit on the size of a file."
8920 #: build/C/man3/ulimit.3:59
8926 #: build/C/man3/ulimit.3:63
8928 "(Not implemented for Linux.) Return the maximum possible address of the "
8933 #: build/C/man3/ulimit.3:63
8939 #: build/C/man3/ulimit.3:67
8941 "(Implemented but no symbolic constant provided.) Return the maximum number "
8942 "of files that the calling process can open."
8946 #: build/C/man3/ulimit.3:74
8948 "On success, B<ulimit>() returns a nonnegative value. On error, -1 is "
8949 "returned, and I<errno> is set appropriately."
8953 #: build/C/man3/ulimit.3:78
8954 msgid "A unprivileged process tried to increase a limit."
8958 #: build/C/man3/ulimit.3:83
8959 msgid "SVr4, POSIX.1-2001. POSIX.1-2008 marks B<ulimit>() as obsolete."
8963 #: build/C/man3/ulimit.3:88
8964 msgid "B<bash>(1), B<getrlimit>(2), B<setrlimit>(2), B<sysconf>(3)"
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