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/qemu-options.h"
35 #include "qemu/error-report.h"
37 #include "sysemu/runstate.h"
38 #include "qemu/cutils.h"
39 #include "qemu/config-file.h"
40 #include "qemu/option.h"
41 #include "qemu/module.h"
44 #include <sys/prctl.h>
45 #include "qemu/async-teardown.h"
49 * Must set all three of these at once.
50 * Legal combinations are unset by name by uid
52 static struct passwd *user_pwd; /* NULL non-NULL NULL */
53 static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
54 static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
56 static const char *chroot_dir;
58 static int daemon_pipe;
60 void os_setup_early_signal_handling(void)
63 sigfillset(&act.sa_mask);
65 act.sa_handler = SIG_IGN;
66 sigaction(SIGPIPE, &act, NULL);
69 static void termsig_handler(int signal, siginfo_t *info, void *c)
71 qemu_system_killed(info->si_signo, info->si_pid);
74 void os_setup_signal_handling(void)
78 memset(&act, 0, sizeof(act));
79 act.sa_sigaction = termsig_handler;
80 act.sa_flags = SA_SIGINFO;
81 sigaction(SIGINT, &act, NULL);
82 sigaction(SIGHUP, &act, NULL);
83 sigaction(SIGTERM, &act, NULL);
86 void os_set_proc_name(const char *s)
88 #if defined(PR_SET_NAME)
92 pstrcpy(name, sizeof(name), s);
93 /* Could rewrite argv[0] too, but that's a bit more complicated.
94 This simple way is enough for `top'. */
95 if (prctl(PR_SET_NAME, name)) {
96 error_report("unable to change process name: %s", strerror(errno));
100 error_report("Change of process name not supported by your OS");
106 static bool os_parse_runas_uid_gid(const char *optarg)
114 rc = qemu_strtoul(optarg, &ep, 0, &lv);
115 got_uid = lv; /* overflow here is ID in C99 */
116 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
120 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
121 got_gid = lv; /* overflow here is ID in C99 */
122 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
133 * Parse OS specific command line options.
134 * return 0 if option handled, -1 otherwise
136 int os_parse_cmd_args(int index, const char *optarg)
139 case QEMU_OPTION_runas:
140 user_pwd = getpwnam(optarg);
144 } else if (!os_parse_runas_uid_gid(optarg)) {
145 error_report("User \"%s\" doesn't exist"
146 " (and is not <uid>:<gid>)",
151 case QEMU_OPTION_chroot:
152 warn_report("option is deprecated, use '-run-with chroot=...' instead");
155 case QEMU_OPTION_daemonize:
158 #if defined(CONFIG_LINUX)
160 case QEMU_OPTION_asyncteardown:
161 init_async_teardown();
164 case QEMU_OPTION_run_with: {
166 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("run-with"),
171 #if defined(CONFIG_LINUX)
172 if (qemu_opt_get_bool(opts, "async-teardown", false)) {
173 init_async_teardown();
176 str = qemu_opt_get(opts, "chroot");
189 static void change_process_uid(void)
191 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
192 assert((user_uid == (uid_t)-1) ==
193 (user_gid == (gid_t)-1));
195 if (user_pwd || user_uid != (uid_t)-1) {
196 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
197 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
198 if (setgid(intended_gid) < 0) {
199 error_report("Failed to setgid(%d)", intended_gid);
203 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
204 error_report("Failed to initgroups(\"%s\", %d)",
205 user_pwd->pw_name, user_pwd->pw_gid);
209 if (setgroups(1, &user_gid) < 0) {
210 error_report("Failed to setgroups(1, [%d])",
215 if (setuid(intended_uid) < 0) {
216 error_report("Failed to setuid(%d)", intended_uid);
219 if (setuid(0) != -1) {
220 error_report("Dropping privileges failed");
226 static void change_root(void)
229 if (chroot(chroot_dir) < 0) {
230 error_report("chroot failed");
234 error_report("not able to chdir to /: %s", strerror(errno));
241 void os_daemonize(void)
247 if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) {
259 len = read(fds[0], &status, 1);
260 } while (len < 0 && errno == EINTR);
262 /* only exit successfully if our child actually wrote
263 * a one-byte zero to our pipe, upon successful init */
264 exit(len == 1 && status == 0 ? 0 : 1);
266 } else if (pid < 0) {
271 daemon_pipe = fds[1];
278 } else if (pid < 0) {
283 signal(SIGTSTP, SIG_IGN);
284 signal(SIGTTOU, SIG_IGN);
285 signal(SIGTTIN, SIG_IGN);
289 void os_setup_post(void)
295 error_report("not able to chdir to /: %s", strerror(errno));
298 fd = RETRY_ON_EINTR(qemu_open_old("/dev/null", O_RDWR));
305 change_process_uid();
313 /* In case -D is given do not redirect stderr to /dev/null */
314 if (!qemu_log_enabled()) {
321 len = write(daemon_pipe, &status, 1);
322 } while (len < 0 && errno == EINTR);
329 void os_set_line_buffering(void)
331 setvbuf(stdout, NULL, _IOLBF, 0);
334 bool is_daemonized(void)
339 int os_set_daemonize(bool d)
350 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
352 error_report("mlockall: %s", strerror(errno));
361 static QemuOptsList qemu_run_with_opts = {
363 .head = QTAILQ_HEAD_INITIALIZER(qemu_run_with_opts.head),
365 #if defined(CONFIG_LINUX)
367 .name = "async-teardown",
368 .type = QEMU_OPT_BOOL,
373 .type = QEMU_OPT_STRING,
375 { /* end of list */ }
379 static void register_runwith(void)
381 qemu_add_opts(&qemu_run_with_opts);
383 opts_init(register_runwith);