Update version for v5.1.0-rc3 release
[qemu.git] / os-posix.c
1 /*
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
26 #include "qemu/osdep.h"
27 #include <sys/wait.h>
28 #include <pwd.h>
29 #include <grp.h>
30 #include <libgen.h>
31
32 #include "qemu-common.h"
33 /* Needed early for CONFIG_BSD etc. */
34 #include "net/slirp.h"
35 #include "qemu-options.h"
36 #include "qemu/error-report.h"
37 #include "qemu/log.h"
38 #include "sysemu/runstate.h"
39 #include "qemu/cutils.h"
40
41 #ifdef CONFIG_LINUX
42 #include <sys/prctl.h>
43 #endif
44
45 /*
46 * Must set all three of these at once.
47 * Legal combinations are unset by name by uid
48 */
49 static struct passwd *user_pwd; /* NULL non-NULL NULL */
50 static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */
51 static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */
52
53 static const char *chroot_dir;
54 static int daemonize;
55 static int daemon_pipe;
56
57 void os_setup_early_signal_handling(void)
58 {
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 }
65
66 static void termsig_handler(int signal, siginfo_t *info, void *c)
67 {
68 qemu_system_killed(info->si_signo, info->si_pid);
69 }
70
71 void os_setup_signal_handling(void)
72 {
73 struct sigaction act;
74
75 memset(&act, 0, sizeof(act));
76 act.sa_sigaction = termsig_handler;
77 act.sa_flags = SA_SIGINFO;
78 sigaction(SIGINT, &act, NULL);
79 sigaction(SIGHUP, &act, NULL);
80 sigaction(SIGTERM, &act, NULL);
81 }
82
83 /*
84 * Find a likely location for support files using the location of the binary.
85 * When running from the build tree this will be "$bindir/../pc-bios".
86 * Otherwise, this is CONFIG_QEMU_DATADIR.
87 *
88 * The caller must use g_free() to free the returned data when it is
89 * no longer required.
90 */
91 char *os_find_datadir(void)
92 {
93 g_autofree char *exec_dir = NULL;
94 g_autofree char *dir = NULL;
95
96 exec_dir = qemu_get_exec_dir();
97 g_return_val_if_fail(exec_dir != NULL, NULL);
98
99 dir = g_build_filename(exec_dir, "..", "pc-bios", NULL);
100 if (g_file_test(dir, G_FILE_TEST_IS_DIR)) {
101 return g_steal_pointer(&dir);
102 }
103
104 return g_strdup(CONFIG_QEMU_DATADIR);
105 }
106
107 void os_set_proc_name(const char *s)
108 {
109 #if defined(PR_SET_NAME)
110 char name[16];
111 if (!s)
112 return;
113 pstrcpy(name, sizeof(name), s);
114 /* Could rewrite argv[0] too, but that's a bit more complicated.
115 This simple way is enough for `top'. */
116 if (prctl(PR_SET_NAME, name)) {
117 error_report("unable to change process name: %s", strerror(errno));
118 exit(1);
119 }
120 #else
121 error_report("Change of process name not supported by your OS");
122 exit(1);
123 #endif
124 }
125
126
127 static bool os_parse_runas_uid_gid(const char *optarg)
128 {
129 unsigned long lv;
130 const char *ep;
131 uid_t got_uid;
132 gid_t got_gid;
133 int rc;
134
135 rc = qemu_strtoul(optarg, &ep, 0, &lv);
136 got_uid = lv; /* overflow here is ID in C99 */
137 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
138 return false;
139 }
140
141 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
142 got_gid = lv; /* overflow here is ID in C99 */
143 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
144 return false;
145 }
146
147 user_pwd = NULL;
148 user_uid = got_uid;
149 user_gid = got_gid;
150 return true;
151 }
152
153 /*
154 * Parse OS specific command line options.
155 * return 0 if option handled, -1 otherwise
156 */
157 int os_parse_cmd_args(int index, const char *optarg)
158 {
159 switch (index) {
160 case QEMU_OPTION_runas:
161 user_pwd = getpwnam(optarg);
162 if (user_pwd) {
163 user_uid = -1;
164 user_gid = -1;
165 } else if (!os_parse_runas_uid_gid(optarg)) {
166 error_report("User \"%s\" doesn't exist"
167 " (and is not <uid>:<gid>)",
168 optarg);
169 exit(1);
170 }
171 break;
172 case QEMU_OPTION_chroot:
173 chroot_dir = optarg;
174 break;
175 case QEMU_OPTION_daemonize:
176 daemonize = 1;
177 break;
178 #if defined(CONFIG_LINUX)
179 case QEMU_OPTION_enablefips:
180 fips_set_state(true);
181 break;
182 #endif
183 default:
184 return -1;
185 }
186
187 return 0;
188 }
189
190 static void change_process_uid(void)
191 {
192 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
193 assert((user_uid == (uid_t)-1) ==
194 (user_gid == (gid_t)-1));
195
196 if (user_pwd || user_uid != (uid_t)-1) {
197 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
198 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
199 if (setgid(intended_gid) < 0) {
200 error_report("Failed to setgid(%d)", intended_gid);
201 exit(1);
202 }
203 if (user_pwd) {
204 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
205 error_report("Failed to initgroups(\"%s\", %d)",
206 user_pwd->pw_name, user_pwd->pw_gid);
207 exit(1);
208 }
209 } else {
210 if (setgroups(1, &user_gid) < 0) {
211 error_report("Failed to setgroups(1, [%d])",
212 user_gid);
213 exit(1);
214 }
215 }
216 if (setuid(intended_uid) < 0) {
217 error_report("Failed to setuid(%d)", intended_uid);
218 exit(1);
219 }
220 if (setuid(0) != -1) {
221 error_report("Dropping privileges failed");
222 exit(1);
223 }
224 }
225 }
226
227 static void change_root(void)
228 {
229 if (chroot_dir) {
230 if (chroot(chroot_dir) < 0) {
231 error_report("chroot failed");
232 exit(1);
233 }
234 if (chdir("/")) {
235 error_report("not able to chdir to /: %s", strerror(errno));
236 exit(1);
237 }
238 }
239
240 }
241
242 void os_daemonize(void)
243 {
244 if (daemonize) {
245 pid_t pid;
246 int fds[2];
247
248 if (pipe(fds) == -1) {
249 exit(1);
250 }
251
252 pid = fork();
253 if (pid > 0) {
254 uint8_t status;
255 ssize_t len;
256
257 close(fds[1]);
258
259 do {
260 len = read(fds[0], &status, 1);
261 } while (len < 0 && errno == EINTR);
262
263 /* only exit successfully if our child actually wrote
264 * a one-byte zero to our pipe, upon successful init */
265 exit(len == 1 && status == 0 ? 0 : 1);
266
267 } else if (pid < 0) {
268 exit(1);
269 }
270
271 close(fds[0]);
272 daemon_pipe = fds[1];
273 qemu_set_cloexec(daemon_pipe);
274
275 setsid();
276
277 pid = fork();
278 if (pid > 0) {
279 exit(0);
280 } else if (pid < 0) {
281 exit(1);
282 }
283 umask(027);
284
285 signal(SIGTSTP, SIG_IGN);
286 signal(SIGTTOU, SIG_IGN);
287 signal(SIGTTIN, SIG_IGN);
288 }
289 }
290
291 void os_setup_post(void)
292 {
293 int fd = 0;
294
295 if (daemonize) {
296 if (chdir("/")) {
297 error_report("not able to chdir to /: %s", strerror(errno));
298 exit(1);
299 }
300 TFR(fd = qemu_open("/dev/null", O_RDWR));
301 if (fd == -1) {
302 exit(1);
303 }
304 }
305
306 change_root();
307 change_process_uid();
308
309 if (daemonize) {
310 uint8_t status = 0;
311 ssize_t len;
312
313 dup2(fd, 0);
314 dup2(fd, 1);
315 /* In case -D is given do not redirect stderr to /dev/null */
316 if (!qemu_logfile) {
317 dup2(fd, 2);
318 }
319
320 close(fd);
321
322 do {
323 len = write(daemon_pipe, &status, 1);
324 } while (len < 0 && errno == EINTR);
325 if (len != 1) {
326 exit(1);
327 }
328 }
329 }
330
331 void os_set_line_buffering(void)
332 {
333 setvbuf(stdout, NULL, _IOLBF, 0);
334 }
335
336 bool is_daemonized(void)
337 {
338 return daemonize;
339 }
340
341 int os_mlock(void)
342 {
343 #ifdef HAVE_MLOCKALL
344 int ret = 0;
345
346 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
347 if (ret < 0) {
348 error_report("mlockall: %s", strerror(errno));
349 }
350
351 return ret;
352 #else
353 return -ENOSYS;
354 #endif
355 }