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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 | ||
26 | #include <unistd.h> | |
27 | #include <fcntl.h> | |
28 | #include <signal.h> | |
8d963e6a JS |
29 | #include <sys/types.h> |
30 | #include <sys/wait.h> | |
69e8b162 JS |
31 | /*needed for MAP_POPULATE before including qemu-options.h */ |
32 | #include <sys/mman.h> | |
8847cfe8 | 33 | #include <pwd.h> |
6170540b | 34 | #include <libgen.h> |
86b645e7 JS |
35 | |
36 | /* Needed early for CONFIG_BSD etc. */ | |
37 | #include "config-host.h" | |
38 | #include "sysemu.h" | |
59a5264b JS |
39 | #include "net/slirp.h" |
40 | #include "qemu-options.h" | |
86b645e7 | 41 | |
ce798cf2 JS |
42 | #ifdef CONFIG_LINUX |
43 | #include <sys/prctl.h> | |
dc7a09cf | 44 | #include <sys/syscall.h> |
ce798cf2 JS |
45 | #endif |
46 | ||
949d31e6 JS |
47 | #ifdef CONFIG_EVENTFD |
48 | #include <sys/eventfd.h> | |
49 | #endif | |
50 | ||
8847cfe8 | 51 | static struct passwd *user_pwd; |
0766379d | 52 | static const char *chroot_dir; |
eb505be1 JS |
53 | static int daemonize; |
54 | static int fds[2]; | |
8847cfe8 | 55 | |
fe98ac14 | 56 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
57 | { |
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 | } | |
8d963e6a | 64 | |
f64622c4 | 65 | static void termsig_handler(int signal, siginfo_t *info, void *c) |
8d963e6a | 66 | { |
f64622c4 | 67 | qemu_system_killed(info->si_signo, info->si_pid); |
8d963e6a JS |
68 | } |
69 | ||
70 | static void sigchld_handler(int signal) | |
71 | { | |
72 | waitpid(-1, NULL, WNOHANG); | |
73 | } | |
74 | ||
75 | void os_setup_signal_handling(void) | |
76 | { | |
77 | struct sigaction act; | |
78 | ||
79 | memset(&act, 0, sizeof(act)); | |
f64622c4 GN |
80 | act.sa_sigaction = termsig_handler; |
81 | act.sa_flags = SA_SIGINFO; | |
8d963e6a JS |
82 | sigaction(SIGINT, &act, NULL); |
83 | sigaction(SIGHUP, &act, NULL); | |
84 | sigaction(SIGTERM, &act, NULL); | |
85 | ||
86 | act.sa_handler = sigchld_handler; | |
87 | act.sa_flags = SA_NOCLDSTOP; | |
88 | sigaction(SIGCHLD, &act, NULL); | |
89 | } | |
6170540b JS |
90 | |
91 | /* Find a likely location for support files using the location of the binary. | |
92 | For installed binaries this will be "$bindir/../share/qemu". When | |
93 | running from the build tree this will be "$bindir/../pc-bios". */ | |
94 | #define SHARE_SUFFIX "/share/qemu" | |
95 | #define BUILD_SUFFIX "/pc-bios" | |
96 | char *os_find_datadir(const char *argv0) | |
97 | { | |
98 | char *dir; | |
99 | char *p = NULL; | |
100 | char *res; | |
101 | char buf[PATH_MAX]; | |
102 | size_t max_len; | |
103 | ||
104 | #if defined(__linux__) | |
105 | { | |
106 | int len; | |
107 | len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); | |
108 | if (len > 0) { | |
109 | buf[len] = 0; | |
110 | p = buf; | |
111 | } | |
112 | } | |
113 | #elif defined(__FreeBSD__) | |
114 | { | |
115 | static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; | |
116 | size_t len = sizeof(buf) - 1; | |
117 | ||
118 | *buf = '\0'; | |
66fe09ee | 119 | if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && |
6170540b JS |
120 | *buf) { |
121 | buf[sizeof(buf) - 1] = '\0'; | |
122 | p = buf; | |
123 | } | |
124 | } | |
125 | #endif | |
126 | /* If we don't have any way of figuring out the actual executable | |
127 | location then try argv[0]. */ | |
128 | if (!p) { | |
129 | p = realpath(argv0, buf); | |
130 | if (!p) { | |
131 | return NULL; | |
132 | } | |
133 | } | |
134 | dir = dirname(p); | |
135 | dir = dirname(dir); | |
136 | ||
137 | max_len = strlen(dir) + | |
138 | MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1; | |
139 | res = qemu_mallocz(max_len); | |
140 | snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX); | |
141 | if (access(res, R_OK)) { | |
142 | snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX); | |
143 | if (access(res, R_OK)) { | |
144 | qemu_free(res); | |
145 | res = NULL; | |
146 | } | |
147 | } | |
148 | ||
149 | return res; | |
150 | } | |
151 | #undef SHARE_SUFFIX | |
152 | #undef BUILD_SUFFIX | |
59a5264b | 153 | |
ce798cf2 JS |
154 | void os_set_proc_name(const char *s) |
155 | { | |
156 | #if defined(PR_SET_NAME) | |
157 | char name[16]; | |
158 | if (!s) | |
159 | return; | |
160 | name[sizeof(name) - 1] = 0; | |
161 | strncpy(name, s, sizeof(name)); | |
162 | /* Could rewrite argv[0] too, but that's a bit more complicated. | |
163 | This simple way is enough for `top'. */ | |
164 | if (prctl(PR_SET_NAME, name)) { | |
165 | perror("unable to change process name"); | |
166 | exit(1); | |
167 | } | |
168 | #else | |
169 | fprintf(stderr, "Change of process name not supported by your OS\n"); | |
170 | exit(1); | |
171 | #endif | |
172 | } | |
173 | ||
59a5264b JS |
174 | /* |
175 | * Parse OS specific command line options. | |
176 | * return 0 if option handled, -1 otherwise | |
177 | */ | |
178 | void os_parse_cmd_args(int index, const char *optarg) | |
179 | { | |
180 | switch (index) { | |
181 | #ifdef CONFIG_SLIRP | |
182 | case QEMU_OPTION_smb: | |
183 | if (net_slirp_smb(optarg) < 0) | |
184 | exit(1); | |
185 | break; | |
186 | #endif | |
8847cfe8 JS |
187 | case QEMU_OPTION_runas: |
188 | user_pwd = getpwnam(optarg); | |
189 | if (!user_pwd) { | |
190 | fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); | |
191 | exit(1); | |
192 | } | |
193 | break; | |
0766379d JS |
194 | case QEMU_OPTION_chroot: |
195 | chroot_dir = optarg; | |
196 | break; | |
eb505be1 JS |
197 | case QEMU_OPTION_daemonize: |
198 | daemonize = 1; | |
199 | break; | |
59a5264b JS |
200 | } |
201 | return; | |
202 | } | |
8847cfe8 | 203 | |
e06eb601 | 204 | static void change_process_uid(void) |
8847cfe8 JS |
205 | { |
206 | if (user_pwd) { | |
207 | if (setgid(user_pwd->pw_gid) < 0) { | |
208 | fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); | |
209 | exit(1); | |
210 | } | |
211 | if (setuid(user_pwd->pw_uid) < 0) { | |
212 | fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); | |
213 | exit(1); | |
214 | } | |
215 | if (setuid(0) != -1) { | |
216 | fprintf(stderr, "Dropping privileges failed\n"); | |
217 | exit(1); | |
218 | } | |
219 | } | |
220 | } | |
0766379d | 221 | |
e06eb601 | 222 | static void change_root(void) |
0766379d JS |
223 | { |
224 | if (chroot_dir) { | |
225 | if (chroot(chroot_dir) < 0) { | |
226 | fprintf(stderr, "chroot failed\n"); | |
227 | exit(1); | |
228 | } | |
229 | if (chdir("/")) { | |
230 | perror("not able to chdir to /"); | |
231 | exit(1); | |
232 | } | |
233 | } | |
234 | ||
235 | } | |
eb505be1 JS |
236 | |
237 | void os_daemonize(void) | |
238 | { | |
239 | if (daemonize) { | |
240 | pid_t pid; | |
241 | ||
242 | if (pipe(fds) == -1) | |
243 | exit(1); | |
244 | ||
245 | pid = fork(); | |
246 | if (pid > 0) { | |
247 | uint8_t status; | |
248 | ssize_t len; | |
249 | ||
250 | close(fds[1]); | |
251 | ||
252 | again: | |
253 | len = read(fds[0], &status, 1); | |
254 | if (len == -1 && (errno == EINTR)) | |
255 | goto again; | |
256 | ||
257 | if (len != 1) | |
258 | exit(1); | |
259 | else if (status == 1) { | |
260 | fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno)); | |
261 | exit(1); | |
262 | } else | |
263 | exit(0); | |
264 | } else if (pid < 0) | |
265 | exit(1); | |
266 | ||
267 | close(fds[0]); | |
268 | qemu_set_cloexec(fds[1]); | |
269 | ||
270 | setsid(); | |
271 | ||
272 | pid = fork(); | |
273 | if (pid > 0) | |
274 | exit(0); | |
275 | else if (pid < 0) | |
276 | exit(1); | |
277 | ||
278 | umask(027); | |
279 | ||
280 | signal(SIGTSTP, SIG_IGN); | |
281 | signal(SIGTTOU, SIG_IGN); | |
282 | signal(SIGTTIN, SIG_IGN); | |
283 | } | |
284 | } | |
285 | ||
286 | void os_setup_post(void) | |
287 | { | |
288 | int fd = 0; | |
289 | ||
290 | if (daemonize) { | |
291 | uint8_t status = 0; | |
292 | ssize_t len; | |
293 | ||
294 | again1: | |
295 | len = write(fds[1], &status, 1); | |
296 | if (len == -1 && (errno == EINTR)) | |
297 | goto again1; | |
298 | ||
299 | if (len != 1) | |
300 | exit(1); | |
301 | ||
302 | if (chdir("/")) { | |
303 | perror("not able to chdir to /"); | |
304 | exit(1); | |
305 | } | |
306 | TFR(fd = qemu_open("/dev/null", O_RDWR)); | |
307 | if (fd == -1) | |
308 | exit(1); | |
309 | } | |
310 | ||
e06eb601 JS |
311 | change_root(); |
312 | change_process_uid(); | |
eb505be1 JS |
313 | |
314 | if (daemonize) { | |
315 | dup2(fd, 0); | |
316 | dup2(fd, 1); | |
317 | dup2(fd, 2); | |
318 | ||
319 | close(fd); | |
320 | } | |
321 | } | |
322 | ||
323 | void os_pidfile_error(void) | |
324 | { | |
325 | if (daemonize) { | |
326 | uint8_t status = 1; | |
327 | if (write(fds[1], &status, 1) != 1) { | |
328 | perror("daemonize. Writing to pipe\n"); | |
329 | } | |
330 | } else | |
331 | fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno)); | |
332 | } | |
9156d763 JS |
333 | |
334 | void os_set_line_buffering(void) | |
335 | { | |
336 | setvbuf(stdout, NULL, _IOLBF, 0); | |
337 | } | |
949d31e6 JS |
338 | |
339 | /* | |
340 | * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set. | |
341 | */ | |
342 | int qemu_eventfd(int fds[2]) | |
343 | { | |
344 | #ifdef CONFIG_EVENTFD | |
345 | int ret; | |
346 | ||
347 | ret = eventfd(0, 0); | |
348 | if (ret >= 0) { | |
349 | fds[0] = ret; | |
350 | qemu_set_cloexec(ret); | |
351 | if ((fds[1] = dup(ret)) == -1) { | |
352 | close(ret); | |
353 | return -1; | |
354 | } | |
355 | qemu_set_cloexec(fds[1]); | |
356 | return 0; | |
357 | } | |
358 | ||
359 | if (errno != ENOSYS) { | |
360 | return -1; | |
361 | } | |
362 | #endif | |
363 | ||
364 | return qemu_pipe(fds); | |
365 | } | |
bc4a957c JS |
366 | |
367 | int qemu_create_pidfile(const char *filename) | |
368 | { | |
369 | char buffer[128]; | |
370 | int len; | |
371 | int fd; | |
372 | ||
373 | fd = qemu_open(filename, O_RDWR | O_CREAT, 0600); | |
374 | if (fd == -1) { | |
375 | return -1; | |
376 | } | |
377 | if (lockf(fd, F_TLOCK, 0) == -1) { | |
378 | return -1; | |
379 | } | |
380 | len = snprintf(buffer, sizeof(buffer), "%ld\n", (long)getpid()); | |
381 | if (write(fd, buffer, len) != len) { | |
382 | return -1; | |
383 | } | |
384 | ||
385 | return 0; | |
386 | } | |
dc7a09cf JK |
387 | |
388 | int qemu_get_thread_id(void) | |
389 | { | |
390 | #if defined (__linux__) | |
391 | return syscall(SYS_gettid); | |
392 | #else | |
393 | return getpid(); | |
394 | #endif | |
395 | } |