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Commit | Line | Data |
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86b645e7 JS |
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 | ||
d38ea87a | 26 | #include "qemu/osdep.h" |
8d963e6a | 27 | #include <sys/wait.h> |
8847cfe8 | 28 | #include <pwd.h> |
cc4662f9 | 29 | #include <grp.h> |
6170540b | 30 | #include <libgen.h> |
86b645e7 JS |
31 | |
32 | /* Needed early for CONFIG_BSD etc. */ | |
59a5264b | 33 | #include "net/slirp.h" |
fd5fc4b1 | 34 | #include "qemu/qemu-options.h" |
f853ac66 | 35 | #include "qemu/error-report.h" |
96c33a45 | 36 | #include "qemu/log.h" |
54d31236 | 37 | #include "sysemu/runstate.h" |
f348b6d1 | 38 | #include "qemu/cutils.h" |
80bd81ca CI |
39 | #include "qemu/config-file.h" |
40 | #include "qemu/option.h" | |
86b645e7 | 41 | |
ce798cf2 JS |
42 | #ifdef CONFIG_LINUX |
43 | #include <sys/prctl.h> | |
c891c24b | 44 | #include "qemu/async-teardown.h" |
949d31e6 JS |
45 | #endif |
46 | ||
2c42f1e8 IJ |
47 | /* |
48 | * Must set all three of these at once. | |
49 | * Legal combinations are unset by name by uid | |
50 | */ | |
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 */ | |
54 | ||
0766379d | 55 | static const char *chroot_dir; |
eb505be1 | 56 | static int daemonize; |
0be5e436 | 57 | static int daemon_pipe; |
8847cfe8 | 58 | |
fe98ac14 | 59 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
60 | { |
61 | struct sigaction act; | |
62 | sigfillset(&act.sa_mask); | |
63 | act.sa_flags = 0; | |
64 | act.sa_handler = SIG_IGN; | |
65 | sigaction(SIGPIPE, &act, NULL); | |
66 | } | |
8d963e6a | 67 | |
f64622c4 | 68 | static void termsig_handler(int signal, siginfo_t *info, void *c) |
8d963e6a | 69 | { |
f64622c4 | 70 | qemu_system_killed(info->si_signo, info->si_pid); |
8d963e6a JS |
71 | } |
72 | ||
8d963e6a JS |
73 | void os_setup_signal_handling(void) |
74 | { | |
75 | struct sigaction act; | |
76 | ||
77 | memset(&act, 0, sizeof(act)); | |
f64622c4 GN |
78 | act.sa_sigaction = termsig_handler; |
79 | act.sa_flags = SA_SIGINFO; | |
8d963e6a JS |
80 | sigaction(SIGINT, &act, NULL); |
81 | sigaction(SIGHUP, &act, NULL); | |
82 | sigaction(SIGTERM, &act, NULL); | |
8d963e6a | 83 | } |
6170540b | 84 | |
ce798cf2 JS |
85 | void os_set_proc_name(const char *s) |
86 | { | |
87 | #if defined(PR_SET_NAME) | |
88 | char name[16]; | |
89 | if (!s) | |
90 | return; | |
3eadc68e | 91 | pstrcpy(name, sizeof(name), s); |
ce798cf2 JS |
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)) { | |
a7aaec14 | 95 | error_report("unable to change process name: %s", strerror(errno)); |
ce798cf2 JS |
96 | exit(1); |
97 | } | |
98 | #else | |
22cd4f48 | 99 | error_report("Change of process name not supported by your OS"); |
ce798cf2 JS |
100 | exit(1); |
101 | #endif | |
102 | } | |
103 | ||
2c42f1e8 IJ |
104 | |
105 | static bool os_parse_runas_uid_gid(const char *optarg) | |
106 | { | |
107 | unsigned long lv; | |
108 | const char *ep; | |
109 | uid_t got_uid; | |
110 | gid_t got_gid; | |
111 | int rc; | |
112 | ||
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) { | |
116 | return false; | |
117 | } | |
118 | ||
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) { | |
122 | return false; | |
123 | } | |
124 | ||
125 | user_pwd = NULL; | |
126 | user_uid = got_uid; | |
127 | user_gid = got_gid; | |
128 | return true; | |
129 | } | |
130 | ||
59a5264b JS |
131 | /* |
132 | * Parse OS specific command line options. | |
133 | * return 0 if option handled, -1 otherwise | |
134 | */ | |
1217d6ca | 135 | int os_parse_cmd_args(int index, const char *optarg) |
59a5264b JS |
136 | { |
137 | switch (index) { | |
8847cfe8 JS |
138 | case QEMU_OPTION_runas: |
139 | user_pwd = getpwnam(optarg); | |
2c42f1e8 IJ |
140 | if (user_pwd) { |
141 | user_uid = -1; | |
142 | user_gid = -1; | |
143 | } else if (!os_parse_runas_uid_gid(optarg)) { | |
144 | error_report("User \"%s\" doesn't exist" | |
145 | " (and is not <uid>:<gid>)", | |
146 | optarg); | |
8847cfe8 JS |
147 | exit(1); |
148 | } | |
149 | break; | |
0766379d JS |
150 | case QEMU_OPTION_chroot: |
151 | chroot_dir = optarg; | |
152 | break; | |
eb505be1 JS |
153 | case QEMU_OPTION_daemonize: |
154 | daemonize = 1; | |
155 | break; | |
c891c24b | 156 | #if defined(CONFIG_LINUX) |
80bd81ca | 157 | /* deprecated */ |
c891c24b CI |
158 | case QEMU_OPTION_asyncteardown: |
159 | init_async_teardown(); | |
160 | break; | |
80bd81ca CI |
161 | case QEMU_OPTION_run_with: { |
162 | QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("run-with"), | |
163 | optarg, false); | |
164 | if (!opts) { | |
165 | exit(1); | |
166 | } | |
167 | if (qemu_opt_get_bool(opts, "async-teardown", false)) { | |
168 | init_async_teardown(); | |
169 | } | |
170 | break; | |
171 | } | |
c891c24b | 172 | #endif |
1217d6ca TH |
173 | default: |
174 | return -1; | |
59a5264b | 175 | } |
1217d6ca TH |
176 | |
177 | return 0; | |
59a5264b | 178 | } |
8847cfe8 | 179 | |
e06eb601 | 180 | static void change_process_uid(void) |
8847cfe8 | 181 | { |
2c42f1e8 IJ |
182 | assert((user_uid == (uid_t)-1) || user_pwd == NULL); |
183 | assert((user_uid == (uid_t)-1) == | |
184 | (user_gid == (gid_t)-1)); | |
185 | ||
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); | |
8847cfe8 JS |
191 | exit(1); |
192 | } | |
2c42f1e8 IJ |
193 | if (user_pwd) { |
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); | |
197 | exit(1); | |
198 | } | |
199 | } else { | |
200 | if (setgroups(1, &user_gid) < 0) { | |
201 | error_report("Failed to setgroups(1, [%d])", | |
202 | user_gid); | |
203 | exit(1); | |
204 | } | |
cc4662f9 | 205 | } |
2c42f1e8 IJ |
206 | if (setuid(intended_uid) < 0) { |
207 | error_report("Failed to setuid(%d)", intended_uid); | |
8847cfe8 JS |
208 | exit(1); |
209 | } | |
210 | if (setuid(0) != -1) { | |
f0a2171b | 211 | error_report("Dropping privileges failed"); |
8847cfe8 JS |
212 | exit(1); |
213 | } | |
214 | } | |
215 | } | |
0766379d | 216 | |
e06eb601 | 217 | static void change_root(void) |
0766379d JS |
218 | { |
219 | if (chroot_dir) { | |
220 | if (chroot(chroot_dir) < 0) { | |
22cd4f48 | 221 | error_report("chroot failed"); |
0766379d JS |
222 | exit(1); |
223 | } | |
224 | if (chdir("/")) { | |
a7aaec14 | 225 | error_report("not able to chdir to /: %s", strerror(errno)); |
0766379d JS |
226 | exit(1); |
227 | } | |
228 | } | |
229 | ||
230 | } | |
eb505be1 JS |
231 | |
232 | void os_daemonize(void) | |
233 | { | |
234 | if (daemonize) { | |
63ce8e15 | 235 | pid_t pid; |
0be5e436 | 236 | int fds[2]; |
eb505be1 | 237 | |
3338a41f | 238 | if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) { |
63ce8e15 GA |
239 | exit(1); |
240 | } | |
eb505be1 | 241 | |
63ce8e15 GA |
242 | pid = fork(); |
243 | if (pid > 0) { | |
244 | uint8_t status; | |
245 | ssize_t len; | |
eb505be1 | 246 | |
63ce8e15 | 247 | close(fds[1]); |
eb505be1 | 248 | |
ccea25f1 MT |
249 | do { |
250 | len = read(fds[0], &status, 1); | |
251 | } while (len < 0 && errno == EINTR); | |
fee78fd6 MT |
252 | |
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); | |
256 | ||
257 | } else if (pid < 0) { | |
258 | exit(1); | |
259 | } | |
eb505be1 | 260 | |
63ce8e15 | 261 | close(fds[0]); |
0be5e436 | 262 | daemon_pipe = fds[1]; |
eb505be1 | 263 | |
63ce8e15 | 264 | setsid(); |
eb505be1 | 265 | |
63ce8e15 GA |
266 | pid = fork(); |
267 | if (pid > 0) { | |
268 | exit(0); | |
269 | } else if (pid < 0) { | |
270 | exit(1); | |
271 | } | |
272 | umask(027); | |
eb505be1 JS |
273 | |
274 | signal(SIGTSTP, SIG_IGN); | |
275 | signal(SIGTTOU, SIG_IGN); | |
276 | signal(SIGTTIN, SIG_IGN); | |
277 | } | |
278 | } | |
279 | ||
280 | void os_setup_post(void) | |
281 | { | |
282 | int fd = 0; | |
283 | ||
284 | if (daemonize) { | |
eb505be1 | 285 | if (chdir("/")) { |
a7aaec14 | 286 | error_report("not able to chdir to /: %s", strerror(errno)); |
eb505be1 JS |
287 | exit(1); |
288 | } | |
8b6aa693 | 289 | fd = RETRY_ON_EINTR(qemu_open_old("/dev/null", O_RDWR)); |
63ce8e15 GA |
290 | if (fd == -1) { |
291 | exit(1); | |
292 | } | |
eb505be1 JS |
293 | } |
294 | ||
e06eb601 JS |
295 | change_root(); |
296 | change_process_uid(); | |
eb505be1 JS |
297 | |
298 | if (daemonize) { | |
25cec2b8 MT |
299 | uint8_t status = 0; |
300 | ssize_t len; | |
301 | ||
eb505be1 JS |
302 | dup2(fd, 0); |
303 | dup2(fd, 1); | |
96c33a45 | 304 | /* In case -D is given do not redirect stderr to /dev/null */ |
229ef2eb | 305 | if (!qemu_log_enabled()) { |
96c33a45 DA |
306 | dup2(fd, 2); |
307 | } | |
eb505be1 JS |
308 | |
309 | close(fd); | |
25cec2b8 MT |
310 | |
311 | do { | |
312 | len = write(daemon_pipe, &status, 1); | |
313 | } while (len < 0 && errno == EINTR); | |
314 | if (len != 1) { | |
315 | exit(1); | |
316 | } | |
eb505be1 JS |
317 | } |
318 | } | |
319 | ||
9156d763 JS |
320 | void os_set_line_buffering(void) |
321 | { | |
322 | setvbuf(stdout, NULL, _IOLBF, 0); | |
323 | } | |
949d31e6 | 324 | |
995ee2bf HM |
325 | bool is_daemonized(void) |
326 | { | |
327 | return daemonize; | |
328 | } | |
888a6bc6 | 329 | |
f22ac472 HR |
330 | int os_set_daemonize(bool d) |
331 | { | |
332 | daemonize = d; | |
333 | return 0; | |
334 | } | |
335 | ||
888a6bc6 SM |
336 | int os_mlock(void) |
337 | { | |
195588cc | 338 | #ifdef HAVE_MLOCKALL |
888a6bc6 SM |
339 | int ret = 0; |
340 | ||
341 | ret = mlockall(MCL_CURRENT | MCL_FUTURE); | |
342 | if (ret < 0) { | |
a7aaec14 | 343 | error_report("mlockall: %s", strerror(errno)); |
888a6bc6 SM |
344 | } |
345 | ||
346 | return ret; | |
195588cc DC |
347 | #else |
348 | return -ENOSYS; | |
349 | #endif | |
888a6bc6 | 350 | } |