4 * Copyright (c) 2003-2008 Fabrice Bellard
5 * Copyright (c) 2010 Red Hat, Inc.
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 #include "qemu/osdep.h"
32 /* Needed early for CONFIG_BSD etc. */
33 #include "net/slirp.h"
34 #include "qemu/error-report.h"
36 #include "sysemu/runstate.h"
37 #include "qemu/cutils.h"
40 #include <sys/prctl.h>
44 * Must set all three of these at once.
45 * Legal combinations are unset by name by uid
47 static struct passwd *user_pwd; /* NULL non-NULL NULL */
48 static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
49 static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
51 static const char *chroot_dir;
53 static int daemon_pipe;
55 void os_setup_early_signal_handling(void)
58 sigfillset(&act.sa_mask);
60 act.sa_handler = SIG_IGN;
61 sigaction(SIGPIPE, &act, NULL);
64 static void termsig_handler(int signal, siginfo_t *info, void *c)
66 qemu_system_killed(info->si_signo, info->si_pid);
69 void os_setup_signal_handling(void)
73 memset(&act, 0, sizeof(act));
74 act.sa_sigaction = termsig_handler;
75 act.sa_flags = SA_SIGINFO;
76 sigaction(SIGINT, &act, NULL);
77 sigaction(SIGHUP, &act, NULL);
78 sigaction(SIGTERM, &act, NULL);
81 void os_set_proc_name(const char *s)
83 #if defined(PR_SET_NAME)
87 pstrcpy(name, sizeof(name), s);
88 /* Could rewrite argv[0] too, but that's a bit more complicated.
89 This simple way is enough for `top'. */
90 if (prctl(PR_SET_NAME, name)) {
91 error_report("unable to change process name: %s", strerror(errno));
95 error_report("Change of process name not supported by your OS");
101 * Prepare to change user ID. optarg can be one of 3 forms:
102 * - a username, in which case user ID will be changed to its uid,
103 * with primary and supplementary groups set up too;
104 * - a numeric uid, in which case only the uid will be set;
105 * - a pair of numeric uid:gid.
107 bool os_set_runas(const char *optarg)
115 user_pwd = getpwnam(optarg);
122 rc = qemu_strtoul(optarg, &ep, 0, &lv);
123 got_uid = lv; /* overflow here is ID in C99 */
124 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
128 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
129 got_gid = lv; /* overflow here is ID in C99 */
130 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
140 static void change_process_uid(void)
142 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
143 assert((user_uid == (uid_t)-1) ==
144 (user_gid == (gid_t)-1));
146 if (user_pwd || user_uid != (uid_t)-1) {
147 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
148 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
149 if (setgid(intended_gid) < 0) {
150 error_report("Failed to setgid(%d)", intended_gid);
154 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
155 error_report("Failed to initgroups(\"%s\", %d)",
156 user_pwd->pw_name, user_pwd->pw_gid);
160 if (setgroups(1, &user_gid) < 0) {
161 error_report("Failed to setgroups(1, [%d])",
166 if (setuid(intended_uid) < 0) {
167 error_report("Failed to setuid(%d)", intended_uid);
170 if (setuid(0) != -1) {
171 error_report("Dropping privileges failed");
177 void os_set_chroot(const char *optarg)
182 static void change_root(void)
185 if (chroot(chroot_dir) < 0) {
186 error_report("chroot failed");
190 error_report("not able to chdir to /: %s", strerror(errno));
197 void os_daemonize(void)
203 if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) {
215 len = read(fds[0], &status, 1);
216 } while (len < 0 && errno == EINTR);
218 /* only exit successfully if our child actually wrote
219 * a one-byte zero to our pipe, upon successful init */
220 exit(len == 1 && status == 0 ? 0 : 1);
222 } else if (pid < 0) {
227 daemon_pipe = fds[1];
234 } else if (pid < 0) {
239 signal(SIGTSTP, SIG_IGN);
240 signal(SIGTTOU, SIG_IGN);
241 signal(SIGTTIN, SIG_IGN);
245 void os_setup_post(void)
251 error_report("not able to chdir to /: %s", strerror(errno));
254 fd = RETRY_ON_EINTR(qemu_open_old("/dev/null", O_RDWR));
261 change_process_uid();
269 /* In case -D is given do not redirect stderr to /dev/null */
270 if (!qemu_log_enabled()) {
277 len = write(daemon_pipe, &status, 1);
278 } while (len < 0 && errno == EINTR);
285 void os_set_line_buffering(void)
287 setvbuf(stdout, NULL, _IOLBF, 0);
290 bool is_daemonized(void)
295 int os_set_daemonize(bool d)
306 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
308 error_report("mlockall: %s", strerror(errno));