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Jes Sorensen86b645e2010-06-10 11:42:19 +02001/*
2 * os-posix.c
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 * Copyright (c) 2010 Red Hat, Inc.
6 *
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:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
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
23 * THE SOFTWARE.
24 */
25
Peter Maydelld38ea872016-01-29 17:50:05 +000026#include "qemu/osdep.h"
Jes Sorensen8d963e62010-06-10 11:42:22 +020027#include <sys/wait.h>
Jes Sorensen8847cfe2010-06-10 11:42:26 +020028#include <pwd.h>
Stefan Hajnoczicc4662f2011-07-09 10:22:07 +010029#include <grp.h>
Jes Sorensen61705402010-06-10 11:42:23 +020030#include <libgen.h>
Jes Sorensen86b645e2010-06-10 11:42:19 +020031
32/* Needed early for CONFIG_BSD etc. */
Jes Sorensen59a52642010-06-10 11:42:25 +020033#include "net/slirp.h"
Paolo Bonzinifd5fc4b2021-05-17 07:34:21 -040034#include "qemu/qemu-options.h"
Thomas Huthf853ac62016-01-13 09:05:32 +010035#include "qemu/error-report.h"
Dimitris Aragiorgis96c33a42016-02-18 13:38:38 +020036#include "qemu/log.h"
Markus Armbruster54d31232019-08-12 07:23:59 +020037#include "sysemu/runstate.h"
Veronia Bahaaf348b6d2016-03-20 19:16:19 +020038#include "qemu/cutils.h"
Jes Sorensen86b645e2010-06-10 11:42:19 +020039
Jes Sorensence798cf2010-06-10 11:42:31 +020040#ifdef CONFIG_LINUX
41#include <sys/prctl.h>
Jes Sorensen949d31e2010-10-26 10:39:22 +020042#endif
43
Ian Jackson2c42f1e2017-09-15 18:10:44 +010044/*
45 * Must set all three of these at once.
46 * Legal combinations are unset by name by uid
47 */
48static struct passwd *user_pwd; /* NULL non-NULL NULL */
49static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
50static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
51
Jes Sorensen07663792010-06-10 11:42:27 +020052static const char *chroot_dir;
Jes Sorenseneb505be2010-06-10 11:42:28 +020053static int daemonize;
Michael Tokarev0be5e432014-10-30 17:30:51 +030054static int daemon_pipe;
Jes Sorensen8847cfe2010-06-10 11:42:26 +020055
Jes Sorensenfe98ac12010-06-10 11:42:21 +020056void os_setup_early_signal_handling(void)
Jes Sorensen86b645e2010-06-10 11:42:19 +020057{
58 struct sigaction act;
59 sigfillset(&act.sa_mask);
60 act.sa_flags = 0;
61 act.sa_handler = SIG_IGN;
62 sigaction(SIGPIPE, &act, NULL);
63}
Jes Sorensen8d963e62010-06-10 11:42:22 +020064
Gleb Natapovf64622c2011-03-15 13:56:04 +020065static void termsig_handler(int signal, siginfo_t *info, void *c)
Jes Sorensen8d963e62010-06-10 11:42:22 +020066{
Gleb Natapovf64622c2011-03-15 13:56:04 +020067 qemu_system_killed(info->si_signo, info->si_pid);
Jes Sorensen8d963e62010-06-10 11:42:22 +020068}
69
Jes Sorensen8d963e62010-06-10 11:42:22 +020070void os_setup_signal_handling(void)
71{
72 struct sigaction act;
73
74 memset(&act, 0, sizeof(act));
Gleb Natapovf64622c2011-03-15 13:56:04 +020075 act.sa_sigaction = termsig_handler;
76 act.sa_flags = SA_SIGINFO;
Jes Sorensen8d963e62010-06-10 11:42:22 +020077 sigaction(SIGINT, &act, NULL);
78 sigaction(SIGHUP, &act, NULL);
79 sigaction(SIGTERM, &act, NULL);
Jes Sorensen8d963e62010-06-10 11:42:22 +020080}
Jes Sorensen61705402010-06-10 11:42:23 +020081
Jes Sorensence798cf2010-06-10 11:42:31 +020082void os_set_proc_name(const char *s)
83{
84#if defined(PR_SET_NAME)
85 char name[16];
86 if (!s)
87 return;
Jim Meyering3eadc682012-10-04 13:09:51 +020088 pstrcpy(name, sizeof(name), s);
Jes Sorensence798cf2010-06-10 11:42:31 +020089 /* Could rewrite argv[0] too, but that's a bit more complicated.
90 This simple way is enough for `top'. */
91 if (prctl(PR_SET_NAME, name)) {
Ian Jacksona7aaec12018-04-16 15:16:23 +010092 error_report("unable to change process name: %s", strerror(errno));
Jes Sorensence798cf2010-06-10 11:42:31 +020093 exit(1);
94 }
95#else
Ian Jackson22cd4f42018-04-16 15:15:51 +010096 error_report("Change of process name not supported by your OS");
Jes Sorensence798cf2010-06-10 11:42:31 +020097 exit(1);
98#endif
99}
100
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100101
102static bool os_parse_runas_uid_gid(const char *optarg)
103{
104 unsigned long lv;
105 const char *ep;
106 uid_t got_uid;
107 gid_t got_gid;
108 int rc;
109
110 rc = qemu_strtoul(optarg, &ep, 0, &lv);
111 got_uid = lv; /* overflow here is ID in C99 */
112 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
113 return false;
114 }
115
116 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
117 got_gid = lv; /* overflow here is ID in C99 */
118 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
119 return false;
120 }
121
122 user_pwd = NULL;
123 user_uid = got_uid;
124 user_gid = got_gid;
125 return true;
126}
127
Jes Sorensen59a52642010-06-10 11:42:25 +0200128/*
129 * Parse OS specific command line options.
130 * return 0 if option handled, -1 otherwise
131 */
Thomas Huth1217d6ca2018-05-04 19:01:07 +0200132int os_parse_cmd_args(int index, const char *optarg)
Jes Sorensen59a52642010-06-10 11:42:25 +0200133{
134 switch (index) {
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200135 case QEMU_OPTION_runas:
136 user_pwd = getpwnam(optarg);
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100137 if (user_pwd) {
138 user_uid = -1;
139 user_gid = -1;
140 } else if (!os_parse_runas_uid_gid(optarg)) {
141 error_report("User \"%s\" doesn't exist"
142 " (and is not <uid>:<gid>)",
143 optarg);
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200144 exit(1);
145 }
146 break;
Jes Sorensen07663792010-06-10 11:42:27 +0200147 case QEMU_OPTION_chroot:
148 chroot_dir = optarg;
149 break;
Jes Sorenseneb505be2010-06-10 11:42:28 +0200150 case QEMU_OPTION_daemonize:
151 daemonize = 1;
152 break;
Thomas Huth1217d6ca2018-05-04 19:01:07 +0200153 default:
154 return -1;
Jes Sorensen59a52642010-06-10 11:42:25 +0200155 }
Thomas Huth1217d6ca2018-05-04 19:01:07 +0200156
157 return 0;
Jes Sorensen59a52642010-06-10 11:42:25 +0200158}
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200159
Jes Sorensene06eb602010-06-10 11:42:29 +0200160static void change_process_uid(void)
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200161{
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100162 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
163 assert((user_uid == (uid_t)-1) ==
164 (user_gid == (gid_t)-1));
165
166 if (user_pwd || user_uid != (uid_t)-1) {
167 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
168 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
169 if (setgid(intended_gid) < 0) {
170 error_report("Failed to setgid(%d)", intended_gid);
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200171 exit(1);
172 }
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100173 if (user_pwd) {
174 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
175 error_report("Failed to initgroups(\"%s\", %d)",
176 user_pwd->pw_name, user_pwd->pw_gid);
177 exit(1);
178 }
179 } else {
180 if (setgroups(1, &user_gid) < 0) {
181 error_report("Failed to setgroups(1, [%d])",
182 user_gid);
183 exit(1);
184 }
Stefan Hajnoczicc4662f2011-07-09 10:22:07 +0100185 }
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100186 if (setuid(intended_uid) < 0) {
187 error_report("Failed to setuid(%d)", intended_uid);
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200188 exit(1);
189 }
190 if (setuid(0) != -1) {
Ian Jacksonf0a21712018-04-16 15:08:03 +0100191 error_report("Dropping privileges failed");
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200192 exit(1);
193 }
194 }
195}
Jes Sorensen07663792010-06-10 11:42:27 +0200196
Jes Sorensene06eb602010-06-10 11:42:29 +0200197static void change_root(void)
Jes Sorensen07663792010-06-10 11:42:27 +0200198{
199 if (chroot_dir) {
200 if (chroot(chroot_dir) < 0) {
Ian Jackson22cd4f42018-04-16 15:15:51 +0100201 error_report("chroot failed");
Jes Sorensen07663792010-06-10 11:42:27 +0200202 exit(1);
203 }
204 if (chdir("/")) {
Ian Jacksona7aaec12018-04-16 15:16:23 +0100205 error_report("not able to chdir to /: %s", strerror(errno));
Jes Sorensen07663792010-06-10 11:42:27 +0200206 exit(1);
207 }
208 }
209
210}
Jes Sorenseneb505be2010-06-10 11:42:28 +0200211
212void os_daemonize(void)
213{
214 if (daemonize) {
Gonglei63ce8e12014-09-26 16:14:30 +0800215 pid_t pid;
Michael Tokarev0be5e432014-10-30 17:30:51 +0300216 int fds[2];
Jes Sorenseneb505be2010-06-10 11:42:28 +0200217
Marc-André Lureau3338a412022-04-22 14:47:59 +0400218 if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) {
Gonglei63ce8e12014-09-26 16:14:30 +0800219 exit(1);
220 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200221
Gonglei63ce8e12014-09-26 16:14:30 +0800222 pid = fork();
223 if (pid > 0) {
224 uint8_t status;
225 ssize_t len;
Jes Sorenseneb505be2010-06-10 11:42:28 +0200226
Gonglei63ce8e12014-09-26 16:14:30 +0800227 close(fds[1]);
Jes Sorenseneb505be2010-06-10 11:42:28 +0200228
Michael Tokarevccea25f2014-10-30 17:37:16 +0300229 do {
230 len = read(fds[0], &status, 1);
231 } while (len < 0 && errno == EINTR);
Michael Tokarevfee78fd2014-10-30 17:40:48 +0300232
233 /* only exit successfully if our child actually wrote
234 * a one-byte zero to our pipe, upon successful init */
235 exit(len == 1 && status == 0 ? 0 : 1);
236
237 } else if (pid < 0) {
238 exit(1);
239 }
Gonglei63ce8e12014-09-26 16:14:30 +0800240
241 close(fds[0]);
Michael Tokarev0be5e432014-10-30 17:30:51 +0300242 daemon_pipe = fds[1];
Gonglei63ce8e12014-09-26 16:14:30 +0800243
244 setsid();
245
246 pid = fork();
247 if (pid > 0) {
248 exit(0);
249 } else if (pid < 0) {
Jes Sorenseneb505be2010-06-10 11:42:28 +0200250 exit(1);
Gonglei63ce8e12014-09-26 16:14:30 +0800251 }
252 umask(027);
Jes Sorenseneb505be2010-06-10 11:42:28 +0200253
254 signal(SIGTSTP, SIG_IGN);
255 signal(SIGTTOU, SIG_IGN);
256 signal(SIGTTIN, SIG_IGN);
257 }
258}
259
260void os_setup_post(void)
261{
262 int fd = 0;
263
264 if (daemonize) {
Jes Sorenseneb505be2010-06-10 11:42:28 +0200265 if (chdir("/")) {
Ian Jacksona7aaec12018-04-16 15:16:23 +0100266 error_report("not able to chdir to /: %s", strerror(errno));
Jes Sorenseneb505be2010-06-10 11:42:28 +0200267 exit(1);
268 }
Daniel P. Berrangé448058a2020-07-21 13:25:21 +0100269 TFR(fd = qemu_open_old("/dev/null", O_RDWR));
Gonglei63ce8e12014-09-26 16:14:30 +0800270 if (fd == -1) {
271 exit(1);
272 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200273 }
274
Jes Sorensene06eb602010-06-10 11:42:29 +0200275 change_root();
276 change_process_uid();
Jes Sorenseneb505be2010-06-10 11:42:28 +0200277
278 if (daemonize) {
Michael Tokarev25cec2b2014-10-30 17:47:46 +0300279 uint8_t status = 0;
280 ssize_t len;
281
Jes Sorenseneb505be2010-06-10 11:42:28 +0200282 dup2(fd, 0);
283 dup2(fd, 1);
Dimitris Aragiorgis96c33a42016-02-18 13:38:38 +0200284 /* In case -D is given do not redirect stderr to /dev/null */
Richard Henderson229ef2e2022-04-17 11:29:45 -0700285 if (!qemu_log_enabled()) {
Dimitris Aragiorgis96c33a42016-02-18 13:38:38 +0200286 dup2(fd, 2);
287 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200288
289 close(fd);
Michael Tokarev25cec2b2014-10-30 17:47:46 +0300290
291 do {
292 len = write(daemon_pipe, &status, 1);
293 } while (len < 0 && errno == EINTR);
294 if (len != 1) {
295 exit(1);
296 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200297 }
298}
299
Jes Sorensen9156d762010-06-10 11:42:30 +0200300void os_set_line_buffering(void)
301{
302 setvbuf(stdout, NULL, _IOLBF, 0);
303}
Jes Sorensen949d31e2010-10-26 10:39:22 +0200304
Hitoshi Mitake995ee2b2012-09-15 01:15:41 +0900305bool is_daemonized(void)
306{
307 return daemonize;
308}
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200309
Hanna Reitzf22ac472022-03-03 17:48:11 +0100310int os_set_daemonize(bool d)
311{
312 daemonize = d;
313 return 0;
314}
315
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200316int os_mlock(void)
317{
David CARLIER195588c2020-07-13 14:36:09 +0100318#ifdef HAVE_MLOCKALL
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200319 int ret = 0;
320
321 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
322 if (ret < 0) {
Ian Jacksona7aaec12018-04-16 15:16:23 +0100323 error_report("mlockall: %s", strerror(errno));
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200324 }
325
326 return ret;
David CARLIER195588c2020-07-13 14:36:09 +0100327#else
328 return -ENOSYS;
329#endif
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200330}