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"
43 #include <sys/prctl.h>
44 #include "qemu/async-teardown.h"
48 * Must set all three of these at once.
49 * Legal combinations are unset by name by uid
51 static struct passwd *user_pwd; /* NULL non-NULL NULL */
52 static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
53 static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
55 static const char *chroot_dir;
57 static int daemon_pipe;
59 void os_setup_early_signal_handling(void)
62 sigfillset(&act.sa_mask);
64 act.sa_handler = SIG_IGN;
65 sigaction(SIGPIPE, &act, NULL);
68 static void termsig_handler(int signal, siginfo_t *info, void *c)
70 qemu_system_killed(info->si_signo, info->si_pid);
73 void os_setup_signal_handling(void)
77 memset(&act, 0, sizeof(act));
78 act.sa_sigaction = termsig_handler;
79 act.sa_flags = SA_SIGINFO;
80 sigaction(SIGINT, &act, NULL);
81 sigaction(SIGHUP, &act, NULL);
82 sigaction(SIGTERM, &act, NULL);
85 void os_set_proc_name(const char *s)
87 #if defined(PR_SET_NAME)
91 pstrcpy(name, sizeof(name), s);
92 /* Could rewrite argv[0] too, but that's a bit more complicated.
93 This simple way is enough for `top'. */
94 if (prctl(PR_SET_NAME, name)) {
95 error_report("unable to change process name: %s", strerror(errno));
99 error_report("Change of process name not supported by your OS");
105 static bool os_parse_runas_uid_gid(const char *optarg)
113 rc = qemu_strtoul(optarg, &ep, 0, &lv);
114 got_uid = lv; /* overflow here is ID in C99 */
115 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
119 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
120 got_gid = lv; /* overflow here is ID in C99 */
121 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
132 * Parse OS specific command line options.
133 * return 0 if option handled, -1 otherwise
135 int os_parse_cmd_args(int index, const char *optarg)
138 case QEMU_OPTION_runas:
139 user_pwd = getpwnam(optarg);
143 } else if (!os_parse_runas_uid_gid(optarg)) {
144 error_report("User \"%s\" doesn't exist"
145 " (and is not <uid>:<gid>)",
150 case QEMU_OPTION_chroot:
153 case QEMU_OPTION_daemonize:
156 #if defined(CONFIG_LINUX)
158 case QEMU_OPTION_asyncteardown:
159 init_async_teardown();
161 case QEMU_OPTION_run_with: {
162 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("run-with"),
167 if (qemu_opt_get_bool(opts, "async-teardown", false)) {
168 init_async_teardown();
180 static void change_process_uid(void)
182 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
183 assert((user_uid == (uid_t)-1) ==
184 (user_gid == (gid_t)-1));
186 if (user_pwd || user_uid != (uid_t)-1) {
187 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
188 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
189 if (setgid(intended_gid) < 0) {
190 error_report("Failed to setgid(%d)", intended_gid);
194 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
195 error_report("Failed to initgroups(\"%s\", %d)",
196 user_pwd->pw_name, user_pwd->pw_gid);
200 if (setgroups(1, &user_gid) < 0) {
201 error_report("Failed to setgroups(1, [%d])",
206 if (setuid(intended_uid) < 0) {
207 error_report("Failed to setuid(%d)", intended_uid);
210 if (setuid(0) != -1) {
211 error_report("Dropping privileges failed");
217 static void change_root(void)
220 if (chroot(chroot_dir) < 0) {
221 error_report("chroot failed");
225 error_report("not able to chdir to /: %s", strerror(errno));
232 void os_daemonize(void)
238 if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) {
250 len = read(fds[0], &status, 1);
251 } while (len < 0 && errno == EINTR);
253 /* only exit successfully if our child actually wrote
254 * a one-byte zero to our pipe, upon successful init */
255 exit(len == 1 && status == 0 ? 0 : 1);
257 } else if (pid < 0) {
262 daemon_pipe = fds[1];
269 } else if (pid < 0) {
274 signal(SIGTSTP, SIG_IGN);
275 signal(SIGTTOU, SIG_IGN);
276 signal(SIGTTIN, SIG_IGN);
280 void os_setup_post(void)
286 error_report("not able to chdir to /: %s", strerror(errno));
289 fd = RETRY_ON_EINTR(qemu_open_old("/dev/null", O_RDWR));
296 change_process_uid();
304 /* In case -D is given do not redirect stderr to /dev/null */
305 if (!qemu_log_enabled()) {
312 len = write(daemon_pipe, &status, 1);
313 } while (len < 0 && errno == EINTR);
320 void os_set_line_buffering(void)
322 setvbuf(stdout, NULL, _IOLBF, 0);
325 bool is_daemonized(void)
330 int os_set_daemonize(bool d)
341 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
343 error_report("mlockall: %s", strerror(errno));