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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> | |
8847cfe8 | 31 | #include <pwd.h> |
6170540b | 32 | #include <libgen.h> |
86b645e7 JS |
33 | |
34 | /* Needed early for CONFIG_BSD etc. */ | |
35 | #include "config-host.h" | |
36 | #include "sysemu.h" | |
59a5264b JS |
37 | #include "net/slirp.h" |
38 | #include "qemu-options.h" | |
86b645e7 | 39 | |
ce798cf2 JS |
40 | #ifdef CONFIG_LINUX |
41 | #include <sys/prctl.h> | |
42 | #endif | |
43 | ||
8847cfe8 | 44 | static struct passwd *user_pwd; |
0766379d | 45 | static const char *chroot_dir; |
eb505be1 JS |
46 | static int daemonize; |
47 | static int fds[2]; | |
8847cfe8 | 48 | |
fe98ac14 | 49 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
50 | { |
51 | struct sigaction act; | |
52 | sigfillset(&act.sa_mask); | |
53 | act.sa_flags = 0; | |
54 | act.sa_handler = SIG_IGN; | |
55 | sigaction(SIGPIPE, &act, NULL); | |
56 | } | |
8d963e6a JS |
57 | |
58 | static void termsig_handler(int signal) | |
59 | { | |
60 | qemu_system_shutdown_request(); | |
61 | } | |
62 | ||
63 | static void sigchld_handler(int signal) | |
64 | { | |
65 | waitpid(-1, NULL, WNOHANG); | |
66 | } | |
67 | ||
68 | void os_setup_signal_handling(void) | |
69 | { | |
70 | struct sigaction act; | |
71 | ||
72 | memset(&act, 0, sizeof(act)); | |
73 | act.sa_handler = termsig_handler; | |
74 | sigaction(SIGINT, &act, NULL); | |
75 | sigaction(SIGHUP, &act, NULL); | |
76 | sigaction(SIGTERM, &act, NULL); | |
77 | ||
78 | act.sa_handler = sigchld_handler; | |
79 | act.sa_flags = SA_NOCLDSTOP; | |
80 | sigaction(SIGCHLD, &act, NULL); | |
81 | } | |
6170540b JS |
82 | |
83 | /* Find a likely location for support files using the location of the binary. | |
84 | For installed binaries this will be "$bindir/../share/qemu". When | |
85 | running from the build tree this will be "$bindir/../pc-bios". */ | |
86 | #define SHARE_SUFFIX "/share/qemu" | |
87 | #define BUILD_SUFFIX "/pc-bios" | |
88 | char *os_find_datadir(const char *argv0) | |
89 | { | |
90 | char *dir; | |
91 | char *p = NULL; | |
92 | char *res; | |
93 | char buf[PATH_MAX]; | |
94 | size_t max_len; | |
95 | ||
96 | #if defined(__linux__) | |
97 | { | |
98 | int len; | |
99 | len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); | |
100 | if (len > 0) { | |
101 | buf[len] = 0; | |
102 | p = buf; | |
103 | } | |
104 | } | |
105 | #elif defined(__FreeBSD__) | |
106 | { | |
107 | static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; | |
108 | size_t len = sizeof(buf) - 1; | |
109 | ||
110 | *buf = '\0'; | |
111 | if (!sysctl(mib, sizeof(mib)/sizeof(*mib), buf, &len, NULL, 0) && | |
112 | *buf) { | |
113 | buf[sizeof(buf) - 1] = '\0'; | |
114 | p = buf; | |
115 | } | |
116 | } | |
117 | #endif | |
118 | /* If we don't have any way of figuring out the actual executable | |
119 | location then try argv[0]. */ | |
120 | if (!p) { | |
121 | p = realpath(argv0, buf); | |
122 | if (!p) { | |
123 | return NULL; | |
124 | } | |
125 | } | |
126 | dir = dirname(p); | |
127 | dir = dirname(dir); | |
128 | ||
129 | max_len = strlen(dir) + | |
130 | MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1; | |
131 | res = qemu_mallocz(max_len); | |
132 | snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX); | |
133 | if (access(res, R_OK)) { | |
134 | snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX); | |
135 | if (access(res, R_OK)) { | |
136 | qemu_free(res); | |
137 | res = NULL; | |
138 | } | |
139 | } | |
140 | ||
141 | return res; | |
142 | } | |
143 | #undef SHARE_SUFFIX | |
144 | #undef BUILD_SUFFIX | |
59a5264b | 145 | |
ce798cf2 JS |
146 | void os_set_proc_name(const char *s) |
147 | { | |
148 | #if defined(PR_SET_NAME) | |
149 | char name[16]; | |
150 | if (!s) | |
151 | return; | |
152 | name[sizeof(name) - 1] = 0; | |
153 | strncpy(name, s, sizeof(name)); | |
154 | /* Could rewrite argv[0] too, but that's a bit more complicated. | |
155 | This simple way is enough for `top'. */ | |
156 | if (prctl(PR_SET_NAME, name)) { | |
157 | perror("unable to change process name"); | |
158 | exit(1); | |
159 | } | |
160 | #else | |
161 | fprintf(stderr, "Change of process name not supported by your OS\n"); | |
162 | exit(1); | |
163 | #endif | |
164 | } | |
165 | ||
59a5264b JS |
166 | /* |
167 | * Parse OS specific command line options. | |
168 | * return 0 if option handled, -1 otherwise | |
169 | */ | |
170 | void os_parse_cmd_args(int index, const char *optarg) | |
171 | { | |
172 | switch (index) { | |
173 | #ifdef CONFIG_SLIRP | |
174 | case QEMU_OPTION_smb: | |
175 | if (net_slirp_smb(optarg) < 0) | |
176 | exit(1); | |
177 | break; | |
178 | #endif | |
8847cfe8 JS |
179 | case QEMU_OPTION_runas: |
180 | user_pwd = getpwnam(optarg); | |
181 | if (!user_pwd) { | |
182 | fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); | |
183 | exit(1); | |
184 | } | |
185 | break; | |
0766379d JS |
186 | case QEMU_OPTION_chroot: |
187 | chroot_dir = optarg; | |
188 | break; | |
eb505be1 JS |
189 | case QEMU_OPTION_daemonize: |
190 | daemonize = 1; | |
191 | break; | |
59a5264b JS |
192 | } |
193 | return; | |
194 | } | |
8847cfe8 | 195 | |
e06eb601 | 196 | static void change_process_uid(void) |
8847cfe8 JS |
197 | { |
198 | if (user_pwd) { | |
199 | if (setgid(user_pwd->pw_gid) < 0) { | |
200 | fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); | |
201 | exit(1); | |
202 | } | |
203 | if (setuid(user_pwd->pw_uid) < 0) { | |
204 | fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); | |
205 | exit(1); | |
206 | } | |
207 | if (setuid(0) != -1) { | |
208 | fprintf(stderr, "Dropping privileges failed\n"); | |
209 | exit(1); | |
210 | } | |
211 | } | |
212 | } | |
0766379d | 213 | |
e06eb601 | 214 | static void change_root(void) |
0766379d JS |
215 | { |
216 | if (chroot_dir) { | |
217 | if (chroot(chroot_dir) < 0) { | |
218 | fprintf(stderr, "chroot failed\n"); | |
219 | exit(1); | |
220 | } | |
221 | if (chdir("/")) { | |
222 | perror("not able to chdir to /"); | |
223 | exit(1); | |
224 | } | |
225 | } | |
226 | ||
227 | } | |
eb505be1 JS |
228 | |
229 | void os_daemonize(void) | |
230 | { | |
231 | if (daemonize) { | |
232 | pid_t pid; | |
233 | ||
234 | if (pipe(fds) == -1) | |
235 | exit(1); | |
236 | ||
237 | pid = fork(); | |
238 | if (pid > 0) { | |
239 | uint8_t status; | |
240 | ssize_t len; | |
241 | ||
242 | close(fds[1]); | |
243 | ||
244 | again: | |
245 | len = read(fds[0], &status, 1); | |
246 | if (len == -1 && (errno == EINTR)) | |
247 | goto again; | |
248 | ||
249 | if (len != 1) | |
250 | exit(1); | |
251 | else if (status == 1) { | |
252 | fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno)); | |
253 | exit(1); | |
254 | } else | |
255 | exit(0); | |
256 | } else if (pid < 0) | |
257 | exit(1); | |
258 | ||
259 | close(fds[0]); | |
260 | qemu_set_cloexec(fds[1]); | |
261 | ||
262 | setsid(); | |
263 | ||
264 | pid = fork(); | |
265 | if (pid > 0) | |
266 | exit(0); | |
267 | else if (pid < 0) | |
268 | exit(1); | |
269 | ||
270 | umask(027); | |
271 | ||
272 | signal(SIGTSTP, SIG_IGN); | |
273 | signal(SIGTTOU, SIG_IGN); | |
274 | signal(SIGTTIN, SIG_IGN); | |
275 | } | |
276 | } | |
277 | ||
278 | void os_setup_post(void) | |
279 | { | |
280 | int fd = 0; | |
281 | ||
282 | if (daemonize) { | |
283 | uint8_t status = 0; | |
284 | ssize_t len; | |
285 | ||
286 | again1: | |
287 | len = write(fds[1], &status, 1); | |
288 | if (len == -1 && (errno == EINTR)) | |
289 | goto again1; | |
290 | ||
291 | if (len != 1) | |
292 | exit(1); | |
293 | ||
294 | if (chdir("/")) { | |
295 | perror("not able to chdir to /"); | |
296 | exit(1); | |
297 | } | |
298 | TFR(fd = qemu_open("/dev/null", O_RDWR)); | |
299 | if (fd == -1) | |
300 | exit(1); | |
301 | } | |
302 | ||
e06eb601 JS |
303 | change_root(); |
304 | change_process_uid(); | |
eb505be1 JS |
305 | |
306 | if (daemonize) { | |
307 | dup2(fd, 0); | |
308 | dup2(fd, 1); | |
309 | dup2(fd, 2); | |
310 | ||
311 | close(fd); | |
312 | } | |
313 | } | |
314 | ||
315 | void os_pidfile_error(void) | |
316 | { | |
317 | if (daemonize) { | |
318 | uint8_t status = 1; | |
319 | if (write(fds[1], &status, 1) != 1) { | |
320 | perror("daemonize. Writing to pipe\n"); | |
321 | } | |
322 | } else | |
323 | fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno)); | |
324 | } | |
9156d763 JS |
325 | |
326 | void os_set_line_buffering(void) | |
327 | { | |
328 | setvbuf(stdout, NULL, _IOLBF, 0); | |
329 | } |