2 .\" Hey Emacs! This file is -*- nroff -*- source.
4 .\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992
5 .\" Parts Copyright (c) 1995 Nicolai Langfeldt (janl@ifi.uio.no), 1/1/95
6 .\" and Copyright (c) 2007 Michael Kerrisk <mtk.manpages@gmail.com>
8 .\" Permission is granted to make and distribute verbatim copies of this
9 .\" manual provided the copyright notice and this permission notice are
10 .\" preserved on all copies.
12 .\" Permission is granted to copy and distribute modified versions of this
13 .\" manual under the conditions for verbatim copying, provided that the
14 .\" entire resulting derived work is distributed under the terms of a
15 .\" permission notice identical to this one.
17 .\" Since the Linux kernel and libraries are constantly changing, this
18 .\" manual page may be incorrect or out-of-date. The author(s) assume no
19 .\" responsibility for errors or omissions, or for damages resulting from
20 .\" the use of the information contained herein. The author(s) may not
21 .\" have taken the same level of care in the production of this manual,
22 .\" which is licensed free of charge, as they might when working
25 .\" Formatted or processed versions of this manual, if unaccompanied by
26 .\" the source, must acknowledge the copyright and authors of this work.
28 .\" Modified by Michael Haardt <michael@moria.de>
29 .\" Modified 1993-07-24 by Rik Faith <faith@cs.unc.edu>
30 .\" Modified 1995-05-18 by Todd Larason <jtl@molehill.org>
31 .\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com>
32 .\" Modified 1995-01-09 by Richard Kettlewell <richard@greenend.org.uk>
33 .\" Modified 1998-05-13 by Michael Haardt <michael@cantor.informatik.rwth-aachen.de>
34 .\" Modified 1999-07-06 by aeb & Albert Cahalan
35 .\" Modified 2000-01-07 by aeb
36 .\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
37 .\" 2007-06-08 mtk: Added example program
38 .\" 2007-07-05 mtk: Added details on underlying system call interfaces
40 .TH STAT 2 2011-10-04 "Linux" "Linux Programmer's Manual"
42 stat, fstat, lstat \- get file status
44 .B #include <sys/types.h>
46 .B #include <sys/stat.h>
48 .B #include <unistd.h>
50 .BI "int stat(const char *" path ", struct stat *" buf );
52 .BI "int fstat(int " fd ", struct stat *" buf );
54 .BI "int lstat(const char *" path ", struct stat *" buf );
57 Feature Test Macro Requirements for glibc (see
58 .BR feature_test_macros (7)):
65 _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
66 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
68 || /* Since glibc 2.10: */ _POSIX_C_SOURCE\ >=\ 200112L
74 These functions return information about a file.
75 No permissions are required on the file itself, but\(emin the case of
80 execute (search) permission is required on all of the directories in
82 that lead to the file.
85 stats the file pointed to by
95 is a symbolic link, then the link itself is stat-ed,
96 not the file that it refers to.
101 except that the file to be stat-ed is specified by the file descriptor
104 All of these system calls return a
106 structure, which contains the following fields:
111 dev_t st_dev; /* ID of device containing file */
112 ino_t st_ino; /* inode number */
113 mode_t st_mode; /* protection */
114 nlink_t st_nlink; /* number of hard links */
115 uid_t st_uid; /* user ID of owner */
116 gid_t st_gid; /* group ID of owner */
117 dev_t st_rdev; /* device ID (if special file) */
118 off_t st_size; /* total size, in bytes */
119 blksize_t st_blksize; /* blocksize for file system I/O */
120 blkcnt_t st_blocks; /* number of 512B blocks allocated */
121 time_t st_atime; /* time of last access */
122 time_t st_mtime; /* time of last modification */
123 time_t st_ctime; /* time of last status change */
130 field describes the device on which this file resides.
135 macros may be useful to decompose the device ID in this field.)
139 field describes the device that this file (inode) represents.
143 field gives the size of the file (if it is a regular
144 file or a symbolic link) in bytes.
145 The size of a symbolic link is the length of the pathname
146 it contains, without a terminating null byte.
150 field indicates the number of blocks allocated to the file, 512-byte units.
151 (This may be smaller than
153 when the file has holes.)
157 field gives the "preferred" blocksize for efficient file system I/O.
158 (Writing to a file in smaller chunks may cause
159 an inefficient read-modify-rewrite.)
161 Not all of the Linux file systems implement all of the time fields.
162 Some file system types allow mounting in such a way that file
163 and/or directory accesses do not cause an update of the
173 and related information in
177 is not updated if a file is opened with the
184 is changed by file accesses, for example, by
191 (of more than zero bytes).
194 may or may not update
199 is changed by file modifications, for example, by
205 (of more than zero bytes).
208 of a directory is changed by the creation or deletion of files
214 changed for changes in owner, group, hard link count, or mode.
218 is changed by writing or by setting inode information
219 (i.e., owner, group, link count, mode, etc.).
221 The following POSIX macros are defined to check the file type using the
227 is it a regular file?
242 symbolic link? (Not in POSIX.1-1996.)
245 socket? (Not in POSIX.1-1996.)
248 The following flags are defined for the
254 S_IFMT 0170000 bit mask for the file type bit fields
255 S_IFSOCK 0140000 socket
256 S_IFLNK 0120000 symbolic link
257 S_IFREG 0100000 regular file
258 S_IFBLK 0060000 block device
259 S_IFDIR 0040000 directory
260 S_IFCHR 0020000 character device
262 S_ISUID 0004000 set UID bit
263 S_ISGID 0002000 set-group-ID bit (see below)
264 S_ISVTX 0001000 sticky bit (see below)
265 S_IRWXU 00700 mask for file owner permissions
266 S_IRUSR 00400 owner has read permission
267 S_IWUSR 00200 owner has write permission
268 S_IXUSR 00100 owner has execute permission
269 S_IRWXG 00070 mask for group permissions
270 S_IRGRP 00040 group has read permission
271 S_IWGRP 00020 group has write permission
272 S_IXGRP 00010 group has execute permission
273 S_IRWXO 00007 mask for permissions for others (not in group)
274 S_IROTH 00004 others have read permission
275 S_IWOTH 00002 others have write permission
276 S_IXOTH 00001 others have execute permission
282 has several special uses.
283 For a directory it indicates that BSD semantics is to be used
284 for that directory: files created there inherit their group ID from
285 the directory, not from the effective group ID of the creating process,
286 and directories created there will also get the
289 For a file that does not have the group execution bit
292 the set-group-ID bit indicates mandatory file/record locking.
296 on a directory means that a file
297 in that directory can be renamed or deleted only by the owner
298 of the file, by the owner of the directory, and by a privileged
301 On success, zero is returned.
302 On error, \-1 is returned, and
304 is set appropriately.
308 Search permission is denied for one of the directories
309 in the path prefix of
312 .BR path_resolution (7).)
322 Too many symbolic links encountered while traversing the path.
336 Out of memory (i.e., kernel memory).
339 A component of the path prefix of
346 refers to a file whose size cannot be represented in the type
348 This can occur when an application compiled on a 32-bit platform without
349 .I -D_FILE_OFFSET_BITS=64
352 on a file whose size exceeds
356 These system calls conform to SVr4, 4.3BSD, POSIX.1-2001.
357 .\" SVr4 documents additional
359 .\" error conditions EINTR, ENOLINK, and EOVERFLOW. SVr4
360 .\" documents additional
364 .\" error conditions EINTR, EMULTIHOP, ENOLINK, and EOVERFLOW.
366 According to POSIX.1-2001,
368 on a symbolic link need return valid information only in the
370 field and the file-type component of the
375 POSIX.-2008 tightens the specification, requiring
377 to return valid information in all fields except the permission bits in
384 fields may be less portable.
385 (They were introduced in BSD.
386 The interpretation differs between systems,
387 and possibly on a single system when NFS mounts are involved.)
388 If you need to obtain the definition of the
396 with the value 500 or greater (before including
400 POSIX.1-1990 did not describe the
410 constants, but instead demanded the use of
416 constants are present in POSIX.1-2011 and later.
423 POSIX.1-1996, but both are present in POSIX.1-2001;
424 the former is from SVID 4, the latter from SUSv2.
426 UNIX V7 (and later systems) had
431 prescribes the synonyms
436 Values that have been (or are) in use on various systems:
439 hex name ls octal description
440 f000 S_IFMT 170000 mask for file type
441 0000 000000 SCO out-of-service inode; BSD unknown
442 type; SVID-v2 and XPG2 have both
443 0 and 0100000 for ordinary file
444 1000 S_IFIFO p| 010000 FIFO (named pipe)
445 2000 S_IFCHR c 020000 character special (V7)
446 3000 S_IFMPC 030000 multiplexed character special (V7)
447 4000 S_IFDIR d/ 040000 directory (V7)
448 5000 S_IFNAM 050000 XENIX named special file
449 with two subtypes, distinguished by
450 \fIst_rdev\fP values 1, 2
451 0001 S_INSEM s 000001 XENIX semaphore subtype of IFNAM
452 0002 S_INSHD m 000002 XENIX shared data subtype of IFNAM
453 6000 S_IFBLK b 060000 block special (V7)
454 7000 S_IFMPB 070000 multiplexed block special (V7)
455 8000 S_IFREG - 100000 regular (V7)
456 9000 S_IFCMP 110000 VxFS compressed
457 9000 S_IFNWK n 110000 network special (HP-UX)
458 a000 S_IFLNK l@ 120000 symbolic link (BSD)
459 b000 S_IFSHAD 130000 Solaris shadow inode for ACL
460 (not seen by userspace)
461 c000 S_IFSOCK s= 140000 socket (BSD; also "S_IFSOC" on VxFS)
462 d000 S_IFDOOR D> 150000 Solaris door
463 e000 S_IFWHT w% 160000 BSD whiteout (not used for inode)
464 0200 S_ISVTX 001000 sticky bit: save swapped text even
467 On nondirectories: don't cache this
469 On directories: restricted deletion
471 0400 S_ISGID 002000 set-group-ID on execution (V7)
472 for directories: use BSD semantics for
474 0400 S_ENFMT 002000 System V file locking enforcement (shared
476 0800 S_ISUID 004000 set-user-ID on execution (V7)
477 0800 S_CDF 004000 directory is a context dependent
481 A sticky command appeared in Version 32V AT&T UNIX.
483 Since kernel 2.5.48, the
485 structure supports nanosecond resolution for the three file timestamp fields.
486 Glibc exposes the nanosecond component of each field using names of the form
492 feature test macro is defined.
493 These fields are specified in POSIX.1-2008, and, starting with version 2.12,
494 glibc also exposes these field names if
496 is defined with the value 200809L or greater, or
498 is defined with the value 700 or greater.
499 If none of the aforementioned macros are defined,
500 then the nanosecond values are exposed with names of the form
502 On file systems that do not support subsecond timestamps,
503 the nanosecond fields are returned with the value 0.
504 .\" As at kernel 2.6.25, XFS and JFS support nanosecond timestamps,
505 .\" but ext2, ext3, and Reiserfs do not.
509 will generally not trigger automounter action, whereas
514 For most files under the
518 does not return the file size in the
520 field; instead the field is returned with the value 0.
521 .SS Underlying kernel interface
522 Over time, increases in the size of the
524 structure have led to three successive versions of
534 (new in kernel 2.4; slot
538 wrapper function hides these details from applications,
539 invoking the most recent version of the system call provided by the kernel,
540 and repacking the returned information if required for old binaries.
541 Similar remarks apply for
546 .\" A note from Andries Brouwer, July 2007
548 .\" > Is the story not rather more complicated for some calls like
551 .\" Yes and no, mostly no. See /usr/include/sys/stat.h .
553 .\" The idea is here not so much that syscalls change, but that
554 .\" the definitions of struct stat and of the types dev_t and mode_t change.
555 .\" This means that libc (even if it does not call the kernel
556 .\" but only calls some internal function) must know what the
557 .\" format of dev_t or of struct stat is.
558 .\" The communication between the application and libc goes via
559 .\" the include file <sys/stat.h> that defines a _STAT_VER and
560 .\" _MKNOD_VER describing the layout of the data that user space
561 .\" uses. Each (almost each) occurrence of stat() is replaced by
562 .\" an occurrence of xstat() where the first parameter of xstat()
563 .\" is this version number _STAT_VER.
565 .\" Now, also the definitions used by the kernel change.
566 .\" But glibc copes with this in the standard way, and the
567 .\" struct stat as returned by the kernel is repacked into
568 .\" the struct stat as expected by the application.
569 .\" Thus, _STAT_VER and this setup cater for the application-libc
570 .\" interface, rather than the libc-kernel interface.
572 .\" (Note that the details depend on gcc being used as c compiler.)
574 The following program calls
576 and displays selected fields in the returned
581 #include <sys/types.h>
582 #include <sys/stat.h>
588 main(int argc, char *argv[])
593 fprintf(stderr, "Usage: %s <pathname>\\n", argv[0]);
597 if (stat(argv[1], &sb) == \-1) {
602 printf("File type: ");
604 switch (sb.st_mode & S_IFMT) {
605 case S_IFBLK: printf("block device\\n"); break;
606 case S_IFCHR: printf("character device\\n"); break;
607 case S_IFDIR: printf("directory\\n"); break;
608 case S_IFIFO: printf("FIFO/pipe\\n"); break;
609 case S_IFLNK: printf("symlink\\n"); break;
610 case S_IFREG: printf("regular file\\n"); break;
611 case S_IFSOCK: printf("socket\\n"); break;
612 default: printf("unknown?\\n"); break;
615 printf("I\-node number: %ld\\n", (long) sb.st_ino);
617 printf("Mode: %lo (octal)\\n",
618 (unsigned long) sb.st_mode);
620 printf("Link count: %ld\\n", (long) sb.st_nlink);
621 printf("Ownership: UID=%ld GID=%ld\\n",
622 (long) sb.st_uid, (long) sb.st_gid);
624 printf("Preferred I/O block size: %ld bytes\\n",
625 (long) sb.st_blksize);
626 printf("File size: %lld bytes\\n",
627 (long long) sb.st_size);
628 printf("Blocks allocated: %lld\\n",
629 (long long) sb.st_blocks);
631 printf("Last status change: %s", ctime(&sb.st_ctime));
632 printf("Last file access: %s", ctime(&sb.st_atime));
633 printf("Last file modification: %s", ctime(&sb.st_mtime));
645 .BR capabilities (7),