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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" |
03e471c4 | 27 | #include <sys/resource.h> |
8d963e6a | 28 | #include <sys/wait.h> |
8847cfe8 | 29 | #include <pwd.h> |
cc4662f9 | 30 | #include <grp.h> |
6170540b | 31 | #include <libgen.h> |
86b645e7 | 32 | |
f853ac66 | 33 | #include "qemu/error-report.h" |
96c33a45 | 34 | #include "qemu/log.h" |
54d31236 | 35 | #include "sysemu/runstate.h" |
f348b6d1 | 36 | #include "qemu/cutils.h" |
86b645e7 | 37 | |
ce798cf2 JS |
38 | #ifdef CONFIG_LINUX |
39 | #include <sys/prctl.h> | |
949d31e6 JS |
40 | #endif |
41 | ||
8847cfe8 | 42 | |
fe98ac14 | 43 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
44 | { |
45 | struct sigaction act; | |
46 | sigfillset(&act.sa_mask); | |
47 | act.sa_flags = 0; | |
48 | act.sa_handler = SIG_IGN; | |
49 | sigaction(SIGPIPE, &act, NULL); | |
50 | } | |
8d963e6a | 51 | |
f64622c4 | 52 | static void termsig_handler(int signal, siginfo_t *info, void *c) |
8d963e6a | 53 | { |
f64622c4 | 54 | qemu_system_killed(info->si_signo, info->si_pid); |
8d963e6a JS |
55 | } |
56 | ||
8d963e6a JS |
57 | void os_setup_signal_handling(void) |
58 | { | |
59 | struct sigaction act; | |
60 | ||
61 | memset(&act, 0, sizeof(act)); | |
f64622c4 GN |
62 | act.sa_sigaction = termsig_handler; |
63 | act.sa_flags = SA_SIGINFO; | |
8d963e6a JS |
64 | sigaction(SIGINT, &act, NULL); |
65 | sigaction(SIGHUP, &act, NULL); | |
66 | sigaction(SIGTERM, &act, NULL); | |
8d963e6a | 67 | } |
6170540b | 68 | |
ce798cf2 JS |
69 | void os_set_proc_name(const char *s) |
70 | { | |
71 | #if defined(PR_SET_NAME) | |
72 | char name[16]; | |
73 | if (!s) | |
74 | return; | |
3eadc68e | 75 | pstrcpy(name, sizeof(name), s); |
ce798cf2 JS |
76 | /* Could rewrite argv[0] too, but that's a bit more complicated. |
77 | This simple way is enough for `top'. */ | |
78 | if (prctl(PR_SET_NAME, name)) { | |
a7aaec14 | 79 | error_report("unable to change process name: %s", strerror(errno)); |
ce798cf2 JS |
80 | exit(1); |
81 | } | |
82 | #else | |
22cd4f48 | 83 | error_report("Change of process name not supported by your OS"); |
ce798cf2 JS |
84 | exit(1); |
85 | #endif | |
86 | } | |
87 | ||
433aed5f MT |
88 | |
89 | /* | |
90 | * Must set all three of these at once. | |
91 | * Legal combinations are unset by name by uid | |
92 | */ | |
93 | static struct passwd *user_pwd; /* NULL non-NULL NULL */ | |
94 | static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */ | |
95 | static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */ | |
96 | ||
22d02515 | 97 | /* |
d2803376 | 98 | * Prepare to change user ID. user_id can be one of 3 forms: |
22d02515 MT |
99 | * - a username, in which case user ID will be changed to its uid, |
100 | * with primary and supplementary groups set up too; | |
101 | * - a numeric uid, in which case only the uid will be set; | |
102 | * - a pair of numeric uid:gid. | |
103 | */ | |
d2803376 | 104 | bool os_set_runas(const char *user_id) |
2c42f1e8 IJ |
105 | { |
106 | unsigned long lv; | |
107 | const char *ep; | |
108 | uid_t got_uid; | |
109 | gid_t got_gid; | |
110 | int rc; | |
111 | ||
d2803376 | 112 | user_pwd = getpwnam(user_id); |
22d02515 MT |
113 | if (user_pwd) { |
114 | user_uid = -1; | |
115 | user_gid = -1; | |
116 | return true; | |
117 | } | |
118 | ||
d2803376 | 119 | rc = qemu_strtoul(user_id, &ep, 0, &lv); |
2c42f1e8 IJ |
120 | got_uid = lv; /* overflow here is ID in C99 */ |
121 | if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) { | |
122 | return false; | |
123 | } | |
124 | ||
125 | rc = qemu_strtoul(ep + 1, 0, 0, &lv); | |
126 | got_gid = lv; /* overflow here is ID in C99 */ | |
127 | if (rc || got_gid != lv || got_gid == (gid_t)-1) { | |
128 | return false; | |
129 | } | |
130 | ||
131 | user_pwd = NULL; | |
132 | user_uid = got_uid; | |
133 | user_gid = got_gid; | |
134 | return true; | |
135 | } | |
136 | ||
e06eb601 | 137 | static void change_process_uid(void) |
8847cfe8 | 138 | { |
2c42f1e8 IJ |
139 | assert((user_uid == (uid_t)-1) || user_pwd == NULL); |
140 | assert((user_uid == (uid_t)-1) == | |
141 | (user_gid == (gid_t)-1)); | |
142 | ||
143 | if (user_pwd || user_uid != (uid_t)-1) { | |
144 | gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid; | |
145 | uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid; | |
146 | if (setgid(intended_gid) < 0) { | |
147 | error_report("Failed to setgid(%d)", intended_gid); | |
8847cfe8 JS |
148 | exit(1); |
149 | } | |
2c42f1e8 IJ |
150 | if (user_pwd) { |
151 | if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { | |
152 | error_report("Failed to initgroups(\"%s\", %d)", | |
153 | user_pwd->pw_name, user_pwd->pw_gid); | |
154 | exit(1); | |
155 | } | |
156 | } else { | |
157 | if (setgroups(1, &user_gid) < 0) { | |
158 | error_report("Failed to setgroups(1, [%d])", | |
159 | user_gid); | |
160 | exit(1); | |
161 | } | |
cc4662f9 | 162 | } |
2c42f1e8 IJ |
163 | if (setuid(intended_uid) < 0) { |
164 | error_report("Failed to setuid(%d)", intended_uid); | |
8847cfe8 JS |
165 | exit(1); |
166 | } | |
167 | if (setuid(0) != -1) { | |
f0a2171b | 168 | error_report("Dropping privileges failed"); |
8847cfe8 JS |
169 | exit(1); |
170 | } | |
171 | } | |
172 | } | |
0766379d | 173 | |
433aed5f MT |
174 | |
175 | static const char *chroot_dir; | |
176 | ||
d2803376 | 177 | void os_set_chroot(const char *path) |
5b156390 | 178 | { |
d2803376 | 179 | chroot_dir = path; |
5b156390 MT |
180 | } |
181 | ||
e06eb601 | 182 | static void change_root(void) |
0766379d JS |
183 | { |
184 | if (chroot_dir) { | |
185 | if (chroot(chroot_dir) < 0) { | |
22cd4f48 | 186 | error_report("chroot failed"); |
0766379d JS |
187 | exit(1); |
188 | } | |
189 | if (chdir("/")) { | |
a7aaec14 | 190 | error_report("not able to chdir to /: %s", strerror(errno)); |
0766379d JS |
191 | exit(1); |
192 | } | |
193 | } | |
194 | ||
195 | } | |
eb505be1 | 196 | |
433aed5f MT |
197 | |
198 | static int daemonize; | |
199 | static int daemon_pipe; | |
200 | ||
201 | bool is_daemonized(void) | |
202 | { | |
203 | return daemonize; | |
204 | } | |
205 | ||
206 | int os_set_daemonize(bool d) | |
207 | { | |
208 | daemonize = d; | |
209 | return 0; | |
210 | } | |
211 | ||
eb505be1 JS |
212 | void os_daemonize(void) |
213 | { | |
214 | if (daemonize) { | |
63ce8e15 | 215 | pid_t pid; |
0be5e436 | 216 | int fds[2]; |
eb505be1 | 217 | |
3338a41f | 218 | if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) { |
63ce8e15 GA |
219 | exit(1); |
220 | } | |
eb505be1 | 221 | |
63ce8e15 GA |
222 | pid = fork(); |
223 | if (pid > 0) { | |
224 | uint8_t status; | |
225 | ssize_t len; | |
eb505be1 | 226 | |
63ce8e15 | 227 | close(fds[1]); |
eb505be1 | 228 | |
ccea25f1 MT |
229 | do { |
230 | len = read(fds[0], &status, 1); | |
231 | } while (len < 0 && errno == EINTR); | |
fee78fd6 MT |
232 | |
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 | } | |
eb505be1 | 240 | |
63ce8e15 | 241 | close(fds[0]); |
0be5e436 | 242 | daemon_pipe = fds[1]; |
eb505be1 | 243 | |
63ce8e15 | 244 | setsid(); |
eb505be1 | 245 | |
63ce8e15 GA |
246 | pid = fork(); |
247 | if (pid > 0) { | |
248 | exit(0); | |
249 | } else if (pid < 0) { | |
250 | exit(1); | |
251 | } | |
252 | umask(027); | |
eb505be1 JS |
253 | |
254 | signal(SIGTSTP, SIG_IGN); | |
255 | signal(SIGTTOU, SIG_IGN); | |
256 | signal(SIGTTIN, SIG_IGN); | |
257 | } | |
258 | } | |
259 | ||
03e471c4 FE |
260 | void os_setup_limits(void) |
261 | { | |
262 | struct rlimit nofile; | |
263 | ||
264 | if (getrlimit(RLIMIT_NOFILE, &nofile) < 0) { | |
265 | warn_report("unable to query NOFILE limit: %s", strerror(errno)); | |
266 | return; | |
267 | } | |
268 | ||
269 | if (nofile.rlim_cur == nofile.rlim_max) { | |
270 | return; | |
271 | } | |
272 | ||
273 | nofile.rlim_cur = nofile.rlim_max; | |
274 | ||
275 | if (setrlimit(RLIMIT_NOFILE, &nofile) < 0) { | |
276 | warn_report("unable to set NOFILE limit: %s", strerror(errno)); | |
277 | return; | |
278 | } | |
279 | } | |
280 | ||
eb505be1 JS |
281 | void os_setup_post(void) |
282 | { | |
283 | int fd = 0; | |
284 | ||
285 | if (daemonize) { | |
eb505be1 | 286 | if (chdir("/")) { |
a7aaec14 | 287 | error_report("not able to chdir to /: %s", strerror(errno)); |
eb505be1 JS |
288 | exit(1); |
289 | } | |
8b6aa693 | 290 | fd = RETRY_ON_EINTR(qemu_open_old("/dev/null", O_RDWR)); |
63ce8e15 GA |
291 | if (fd == -1) { |
292 | exit(1); | |
293 | } | |
eb505be1 JS |
294 | } |
295 | ||
e06eb601 JS |
296 | change_root(); |
297 | change_process_uid(); | |
eb505be1 JS |
298 | |
299 | if (daemonize) { | |
25cec2b8 MT |
300 | uint8_t status = 0; |
301 | ssize_t len; | |
302 | ||
eb505be1 JS |
303 | dup2(fd, 0); |
304 | dup2(fd, 1); | |
96c33a45 | 305 | /* In case -D is given do not redirect stderr to /dev/null */ |
229ef2eb | 306 | if (!qemu_log_enabled()) { |
96c33a45 DA |
307 | dup2(fd, 2); |
308 | } | |
eb505be1 JS |
309 | |
310 | close(fd); | |
25cec2b8 MT |
311 | |
312 | do { | |
313 | len = write(daemon_pipe, &status, 1); | |
314 | } while (len < 0 && errno == EINTR); | |
315 | if (len != 1) { | |
316 | exit(1); | |
317 | } | |
eb505be1 JS |
318 | } |
319 | } | |
320 | ||
9156d763 JS |
321 | void os_set_line_buffering(void) |
322 | { | |
323 | setvbuf(stdout, NULL, _IOLBF, 0); | |
324 | } | |
949d31e6 | 325 | |
888a6bc6 SM |
326 | int os_mlock(void) |
327 | { | |
195588cc | 328 | #ifdef HAVE_MLOCKALL |
888a6bc6 SM |
329 | int ret = 0; |
330 | ||
331 | ret = mlockall(MCL_CURRENT | MCL_FUTURE); | |
332 | if (ret < 0) { | |
a7aaec14 | 333 | error_report("mlockall: %s", strerror(errno)); |
888a6bc6 SM |
334 | } |
335 | ||
336 | return ret; | |
195588cc DC |
337 | #else |
338 | return -ENOSYS; | |
339 | #endif | |
888a6bc6 | 340 | } |