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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
Markus Armbrustera8d25322019-05-23 16:35:08 +020032#include "qemu-common.h"
Jes Sorensen86b645e2010-06-10 11:42:19 +020033/* Needed early for CONFIG_BSD etc. */
Jes Sorensen59a52642010-06-10 11:42:25 +020034#include "net/slirp.h"
Paolo Bonzinifd5fc4b2021-05-17 07:34:21 -040035#include "qemu/qemu-options.h"
Thomas Huthf853ac62016-01-13 09:05:32 +010036#include "qemu/error-report.h"
Dimitris Aragiorgis96c33a42016-02-18 13:38:38 +020037#include "qemu/log.h"
Markus Armbruster54d31232019-08-12 07:23:59 +020038#include "sysemu/runstate.h"
Veronia Bahaaf348b6d2016-03-20 19:16:19 +020039#include "qemu/cutils.h"
Jes Sorensen86b645e2010-06-10 11:42:19 +020040
Jes Sorensence798cf2010-06-10 11:42:31 +020041#ifdef CONFIG_LINUX
42#include <sys/prctl.h>
Jes Sorensen949d31e2010-10-26 10:39:22 +020043#endif
44
Ian Jackson2c42f1e2017-09-15 18:10:44 +010045/*
46 * Must set all three of these at once.
47 * Legal combinations are unset by name by uid
48 */
49static struct passwd *user_pwd; /* NULL non-NULL NULL */
50static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
51static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
52
Jes Sorensen07663792010-06-10 11:42:27 +020053static const char *chroot_dir;
Jes Sorenseneb505be2010-06-10 11:42:28 +020054static int daemonize;
Michael Tokarev0be5e432014-10-30 17:30:51 +030055static int daemon_pipe;
Jes Sorensen8847cfe2010-06-10 11:42:26 +020056
Jes Sorensenfe98ac12010-06-10 11:42:21 +020057void os_setup_early_signal_handling(void)
Jes Sorensen86b645e2010-06-10 11:42:19 +020058{
59 struct sigaction act;
60 sigfillset(&act.sa_mask);
61 act.sa_flags = 0;
62 act.sa_handler = SIG_IGN;
63 sigaction(SIGPIPE, &act, NULL);
64}
Jes Sorensen8d963e62010-06-10 11:42:22 +020065
Gleb Natapovf64622c2011-03-15 13:56:04 +020066static void termsig_handler(int signal, siginfo_t *info, void *c)
Jes Sorensen8d963e62010-06-10 11:42:22 +020067{
Gleb Natapovf64622c2011-03-15 13:56:04 +020068 qemu_system_killed(info->si_signo, info->si_pid);
Jes Sorensen8d963e62010-06-10 11:42:22 +020069}
70
Jes Sorensen8d963e62010-06-10 11:42:22 +020071void os_setup_signal_handling(void)
72{
73 struct sigaction act;
74
75 memset(&act, 0, sizeof(act));
Gleb Natapovf64622c2011-03-15 13:56:04 +020076 act.sa_sigaction = termsig_handler;
77 act.sa_flags = SA_SIGINFO;
Jes Sorensen8d963e62010-06-10 11:42:22 +020078 sigaction(SIGINT, &act, NULL);
79 sigaction(SIGHUP, &act, NULL);
80 sigaction(SIGTERM, &act, NULL);
Jes Sorensen8d963e62010-06-10 11:42:22 +020081}
Jes Sorensen61705402010-06-10 11:42:23 +020082
Jes Sorensence798cf2010-06-10 11:42:31 +020083void os_set_proc_name(const char *s)
84{
85#if defined(PR_SET_NAME)
86 char name[16];
87 if (!s)
88 return;
Jim Meyering3eadc682012-10-04 13:09:51 +020089 pstrcpy(name, sizeof(name), s);
Jes Sorensence798cf2010-06-10 11:42:31 +020090 /* Could rewrite argv[0] too, but that's a bit more complicated.
91 This simple way is enough for `top'. */
92 if (prctl(PR_SET_NAME, name)) {
Ian Jacksona7aaec12018-04-16 15:16:23 +010093 error_report("unable to change process name: %s", strerror(errno));
Jes Sorensence798cf2010-06-10 11:42:31 +020094 exit(1);
95 }
96#else
Ian Jackson22cd4f42018-04-16 15:15:51 +010097 error_report("Change of process name not supported by your OS");
Jes Sorensence798cf2010-06-10 11:42:31 +020098 exit(1);
99#endif
100}
101
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100102
103static bool os_parse_runas_uid_gid(const char *optarg)
104{
105 unsigned long lv;
106 const char *ep;
107 uid_t got_uid;
108 gid_t got_gid;
109 int rc;
110
111 rc = qemu_strtoul(optarg, &ep, 0, &lv);
112 got_uid = lv; /* overflow here is ID in C99 */
113 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
114 return false;
115 }
116
117 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
118 got_gid = lv; /* overflow here is ID in C99 */
119 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
120 return false;
121 }
122
123 user_pwd = NULL;
124 user_uid = got_uid;
125 user_gid = got_gid;
126 return true;
127}
128
Jes Sorensen59a52642010-06-10 11:42:25 +0200129/*
130 * Parse OS specific command line options.
131 * return 0 if option handled, -1 otherwise
132 */
Thomas Huth1217d6ca2018-05-04 19:01:07 +0200133int os_parse_cmd_args(int index, const char *optarg)
Jes Sorensen59a52642010-06-10 11:42:25 +0200134{
135 switch (index) {
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200136 case QEMU_OPTION_runas:
137 user_pwd = getpwnam(optarg);
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100138 if (user_pwd) {
139 user_uid = -1;
140 user_gid = -1;
141 } else if (!os_parse_runas_uid_gid(optarg)) {
142 error_report("User \"%s\" doesn't exist"
143 " (and is not <uid>:<gid>)",
144 optarg);
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200145 exit(1);
146 }
147 break;
Jes Sorensen07663792010-06-10 11:42:27 +0200148 case QEMU_OPTION_chroot:
149 chroot_dir = optarg;
150 break;
Jes Sorenseneb505be2010-06-10 11:42:28 +0200151 case QEMU_OPTION_daemonize:
152 daemonize = 1;
153 break;
Anthony Liguori70678b82012-08-03 18:28:37 -0500154#if defined(CONFIG_LINUX)
155 case QEMU_OPTION_enablefips:
Daniel P. Berrangé16631022020-10-20 17:08:27 +0100156 warn_report("-enable-fips is deprecated, please build QEMU with "
157 "the `libgcrypt` library as the cryptography provider "
158 "to enable FIPS compliance");
Anthony Liguori70678b82012-08-03 18:28:37 -0500159 fips_set_state(true);
160 break;
161#endif
Thomas Huth1217d6ca2018-05-04 19:01:07 +0200162 default:
163 return -1;
Jes Sorensen59a52642010-06-10 11:42:25 +0200164 }
Thomas Huth1217d6ca2018-05-04 19:01:07 +0200165
166 return 0;
Jes Sorensen59a52642010-06-10 11:42:25 +0200167}
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200168
Jes Sorensene06eb602010-06-10 11:42:29 +0200169static void change_process_uid(void)
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200170{
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100171 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
172 assert((user_uid == (uid_t)-1) ==
173 (user_gid == (gid_t)-1));
174
175 if (user_pwd || user_uid != (uid_t)-1) {
176 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
177 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
178 if (setgid(intended_gid) < 0) {
179 error_report("Failed to setgid(%d)", intended_gid);
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200180 exit(1);
181 }
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100182 if (user_pwd) {
183 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
184 error_report("Failed to initgroups(\"%s\", %d)",
185 user_pwd->pw_name, user_pwd->pw_gid);
186 exit(1);
187 }
188 } else {
189 if (setgroups(1, &user_gid) < 0) {
190 error_report("Failed to setgroups(1, [%d])",
191 user_gid);
192 exit(1);
193 }
Stefan Hajnoczicc4662f2011-07-09 10:22:07 +0100194 }
Ian Jackson2c42f1e2017-09-15 18:10:44 +0100195 if (setuid(intended_uid) < 0) {
196 error_report("Failed to setuid(%d)", intended_uid);
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200197 exit(1);
198 }
199 if (setuid(0) != -1) {
Ian Jacksonf0a21712018-04-16 15:08:03 +0100200 error_report("Dropping privileges failed");
Jes Sorensen8847cfe2010-06-10 11:42:26 +0200201 exit(1);
202 }
203 }
204}
Jes Sorensen07663792010-06-10 11:42:27 +0200205
Jes Sorensene06eb602010-06-10 11:42:29 +0200206static void change_root(void)
Jes Sorensen07663792010-06-10 11:42:27 +0200207{
208 if (chroot_dir) {
209 if (chroot(chroot_dir) < 0) {
Ian Jackson22cd4f42018-04-16 15:15:51 +0100210 error_report("chroot failed");
Jes Sorensen07663792010-06-10 11:42:27 +0200211 exit(1);
212 }
213 if (chdir("/")) {
Ian Jacksona7aaec12018-04-16 15:16:23 +0100214 error_report("not able to chdir to /: %s", strerror(errno));
Jes Sorensen07663792010-06-10 11:42:27 +0200215 exit(1);
216 }
217 }
218
219}
Jes Sorenseneb505be2010-06-10 11:42:28 +0200220
221void os_daemonize(void)
222{
223 if (daemonize) {
Gonglei63ce8e12014-09-26 16:14:30 +0800224 pid_t pid;
Michael Tokarev0be5e432014-10-30 17:30:51 +0300225 int fds[2];
Jes Sorenseneb505be2010-06-10 11:42:28 +0200226
Gonglei63ce8e12014-09-26 16:14:30 +0800227 if (pipe(fds) == -1) {
228 exit(1);
229 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200230
Gonglei63ce8e12014-09-26 16:14:30 +0800231 pid = fork();
232 if (pid > 0) {
233 uint8_t status;
234 ssize_t len;
Jes Sorenseneb505be2010-06-10 11:42:28 +0200235
Gonglei63ce8e12014-09-26 16:14:30 +0800236 close(fds[1]);
Jes Sorenseneb505be2010-06-10 11:42:28 +0200237
Michael Tokarevccea25f2014-10-30 17:37:16 +0300238 do {
239 len = read(fds[0], &status, 1);
240 } while (len < 0 && errno == EINTR);
Michael Tokarevfee78fd2014-10-30 17:40:48 +0300241
242 /* only exit successfully if our child actually wrote
243 * a one-byte zero to our pipe, upon successful init */
244 exit(len == 1 && status == 0 ? 0 : 1);
245
246 } else if (pid < 0) {
247 exit(1);
248 }
Gonglei63ce8e12014-09-26 16:14:30 +0800249
250 close(fds[0]);
Michael Tokarev0be5e432014-10-30 17:30:51 +0300251 daemon_pipe = fds[1];
252 qemu_set_cloexec(daemon_pipe);
Gonglei63ce8e12014-09-26 16:14:30 +0800253
254 setsid();
255
256 pid = fork();
257 if (pid > 0) {
258 exit(0);
259 } else if (pid < 0) {
Jes Sorenseneb505be2010-06-10 11:42:28 +0200260 exit(1);
Gonglei63ce8e12014-09-26 16:14:30 +0800261 }
262 umask(027);
Jes Sorenseneb505be2010-06-10 11:42:28 +0200263
264 signal(SIGTSTP, SIG_IGN);
265 signal(SIGTTOU, SIG_IGN);
266 signal(SIGTTIN, SIG_IGN);
267 }
268}
269
270void os_setup_post(void)
271{
272 int fd = 0;
273
274 if (daemonize) {
Jes Sorenseneb505be2010-06-10 11:42:28 +0200275 if (chdir("/")) {
Ian Jacksona7aaec12018-04-16 15:16:23 +0100276 error_report("not able to chdir to /: %s", strerror(errno));
Jes Sorenseneb505be2010-06-10 11:42:28 +0200277 exit(1);
278 }
Daniel P. Berrangé448058a2020-07-21 13:25:21 +0100279 TFR(fd = qemu_open_old("/dev/null", O_RDWR));
Gonglei63ce8e12014-09-26 16:14:30 +0800280 if (fd == -1) {
281 exit(1);
282 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200283 }
284
Jes Sorensene06eb602010-06-10 11:42:29 +0200285 change_root();
286 change_process_uid();
Jes Sorenseneb505be2010-06-10 11:42:28 +0200287
288 if (daemonize) {
Michael Tokarev25cec2b2014-10-30 17:47:46 +0300289 uint8_t status = 0;
290 ssize_t len;
291
Jes Sorenseneb505be2010-06-10 11:42:28 +0200292 dup2(fd, 0);
293 dup2(fd, 1);
Dimitris Aragiorgis96c33a42016-02-18 13:38:38 +0200294 /* In case -D is given do not redirect stderr to /dev/null */
295 if (!qemu_logfile) {
296 dup2(fd, 2);
297 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200298
299 close(fd);
Michael Tokarev25cec2b2014-10-30 17:47:46 +0300300
301 do {
302 len = write(daemon_pipe, &status, 1);
303 } while (len < 0 && errno == EINTR);
304 if (len != 1) {
305 exit(1);
306 }
Jes Sorenseneb505be2010-06-10 11:42:28 +0200307 }
308}
309
Jes Sorensen9156d762010-06-10 11:42:30 +0200310void os_set_line_buffering(void)
311{
312 setvbuf(stdout, NULL, _IOLBF, 0);
313}
Jes Sorensen949d31e2010-10-26 10:39:22 +0200314
Hitoshi Mitake995ee2b2012-09-15 01:15:41 +0900315bool is_daemonized(void)
316{
317 return daemonize;
318}
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200319
320int os_mlock(void)
321{
David CARLIER195588c2020-07-13 14:36:09 +0100322#ifdef HAVE_MLOCKALL
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200323 int ret = 0;
324
325 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
326 if (ret < 0) {
Ian Jacksona7aaec12018-04-16 15:16:23 +0100327 error_report("mlockall: %s", strerror(errno));
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200328 }
329
330 return ret;
David CARLIER195588c2020-07-13 14:36:09 +0100331#else
332 return -ENOSYS;
333#endif
Satoru Moriya888a6bc2013-04-19 16:42:06 +0200334}