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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> | |
44 | #endif | |
45 | ||
8847cfe8 | 46 | static struct passwd *user_pwd; |
0766379d | 47 | static const char *chroot_dir; |
eb505be1 JS |
48 | static int daemonize; |
49 | static int fds[2]; | |
8847cfe8 | 50 | |
fe98ac14 | 51 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
52 | { |
53 | struct sigaction act; | |
54 | sigfillset(&act.sa_mask); | |
55 | act.sa_flags = 0; | |
56 | act.sa_handler = SIG_IGN; | |
57 | sigaction(SIGPIPE, &act, NULL); | |
58 | } | |
8d963e6a JS |
59 | |
60 | static void termsig_handler(int signal) | |
61 | { | |
62 | qemu_system_shutdown_request(); | |
63 | } | |
64 | ||
65 | static void sigchld_handler(int signal) | |
66 | { | |
67 | waitpid(-1, NULL, WNOHANG); | |
68 | } | |
69 | ||
70 | void os_setup_signal_handling(void) | |
71 | { | |
72 | struct sigaction act; | |
73 | ||
74 | memset(&act, 0, sizeof(act)); | |
75 | act.sa_handler = termsig_handler; | |
76 | sigaction(SIGINT, &act, NULL); | |
77 | sigaction(SIGHUP, &act, NULL); | |
78 | sigaction(SIGTERM, &act, NULL); | |
79 | ||
80 | act.sa_handler = sigchld_handler; | |
81 | act.sa_flags = SA_NOCLDSTOP; | |
82 | sigaction(SIGCHLD, &act, NULL); | |
83 | } | |
6170540b JS |
84 | |
85 | /* Find a likely location for support files using the location of the binary. | |
86 | For installed binaries this will be "$bindir/../share/qemu". When | |
87 | running from the build tree this will be "$bindir/../pc-bios". */ | |
88 | #define SHARE_SUFFIX "/share/qemu" | |
89 | #define BUILD_SUFFIX "/pc-bios" | |
90 | char *os_find_datadir(const char *argv0) | |
91 | { | |
92 | char *dir; | |
93 | char *p = NULL; | |
94 | char *res; | |
95 | char buf[PATH_MAX]; | |
96 | size_t max_len; | |
97 | ||
98 | #if defined(__linux__) | |
99 | { | |
100 | int len; | |
101 | len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); | |
102 | if (len > 0) { | |
103 | buf[len] = 0; | |
104 | p = buf; | |
105 | } | |
106 | } | |
107 | #elif defined(__FreeBSD__) | |
108 | { | |
109 | static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; | |
110 | size_t len = sizeof(buf) - 1; | |
111 | ||
112 | *buf = '\0'; | |
113 | if (!sysctl(mib, sizeof(mib)/sizeof(*mib), buf, &len, NULL, 0) && | |
114 | *buf) { | |
115 | buf[sizeof(buf) - 1] = '\0'; | |
116 | p = buf; | |
117 | } | |
118 | } | |
119 | #endif | |
120 | /* If we don't have any way of figuring out the actual executable | |
121 | location then try argv[0]. */ | |
122 | if (!p) { | |
123 | p = realpath(argv0, buf); | |
124 | if (!p) { | |
125 | return NULL; | |
126 | } | |
127 | } | |
128 | dir = dirname(p); | |
129 | dir = dirname(dir); | |
130 | ||
131 | max_len = strlen(dir) + | |
132 | MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1; | |
133 | res = qemu_mallocz(max_len); | |
134 | snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX); | |
135 | if (access(res, R_OK)) { | |
136 | snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX); | |
137 | if (access(res, R_OK)) { | |
138 | qemu_free(res); | |
139 | res = NULL; | |
140 | } | |
141 | } | |
142 | ||
143 | return res; | |
144 | } | |
145 | #undef SHARE_SUFFIX | |
146 | #undef BUILD_SUFFIX | |
59a5264b | 147 | |
ce798cf2 JS |
148 | void os_set_proc_name(const char *s) |
149 | { | |
150 | #if defined(PR_SET_NAME) | |
151 | char name[16]; | |
152 | if (!s) | |
153 | return; | |
154 | name[sizeof(name) - 1] = 0; | |
155 | strncpy(name, s, sizeof(name)); | |
156 | /* Could rewrite argv[0] too, but that's a bit more complicated. | |
157 | This simple way is enough for `top'. */ | |
158 | if (prctl(PR_SET_NAME, name)) { | |
159 | perror("unable to change process name"); | |
160 | exit(1); | |
161 | } | |
162 | #else | |
163 | fprintf(stderr, "Change of process name not supported by your OS\n"); | |
164 | exit(1); | |
165 | #endif | |
166 | } | |
167 | ||
59a5264b JS |
168 | /* |
169 | * Parse OS specific command line options. | |
170 | * return 0 if option handled, -1 otherwise | |
171 | */ | |
172 | void os_parse_cmd_args(int index, const char *optarg) | |
173 | { | |
174 | switch (index) { | |
175 | #ifdef CONFIG_SLIRP | |
176 | case QEMU_OPTION_smb: | |
177 | if (net_slirp_smb(optarg) < 0) | |
178 | exit(1); | |
179 | break; | |
180 | #endif | |
8847cfe8 JS |
181 | case QEMU_OPTION_runas: |
182 | user_pwd = getpwnam(optarg); | |
183 | if (!user_pwd) { | |
184 | fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); | |
185 | exit(1); | |
186 | } | |
187 | break; | |
0766379d JS |
188 | case QEMU_OPTION_chroot: |
189 | chroot_dir = optarg; | |
190 | break; | |
eb505be1 JS |
191 | case QEMU_OPTION_daemonize: |
192 | daemonize = 1; | |
193 | break; | |
59a5264b JS |
194 | } |
195 | return; | |
196 | } | |
8847cfe8 | 197 | |
e06eb601 | 198 | static void change_process_uid(void) |
8847cfe8 JS |
199 | { |
200 | if (user_pwd) { | |
201 | if (setgid(user_pwd->pw_gid) < 0) { | |
202 | fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); | |
203 | exit(1); | |
204 | } | |
205 | if (setuid(user_pwd->pw_uid) < 0) { | |
206 | fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); | |
207 | exit(1); | |
208 | } | |
209 | if (setuid(0) != -1) { | |
210 | fprintf(stderr, "Dropping privileges failed\n"); | |
211 | exit(1); | |
212 | } | |
213 | } | |
214 | } | |
0766379d | 215 | |
e06eb601 | 216 | static void change_root(void) |
0766379d JS |
217 | { |
218 | if (chroot_dir) { | |
219 | if (chroot(chroot_dir) < 0) { | |
220 | fprintf(stderr, "chroot failed\n"); | |
221 | exit(1); | |
222 | } | |
223 | if (chdir("/")) { | |
224 | perror("not able to chdir to /"); | |
225 | exit(1); | |
226 | } | |
227 | } | |
228 | ||
229 | } | |
eb505be1 JS |
230 | |
231 | void os_daemonize(void) | |
232 | { | |
233 | if (daemonize) { | |
234 | pid_t pid; | |
235 | ||
236 | if (pipe(fds) == -1) | |
237 | exit(1); | |
238 | ||
239 | pid = fork(); | |
240 | if (pid > 0) { | |
241 | uint8_t status; | |
242 | ssize_t len; | |
243 | ||
244 | close(fds[1]); | |
245 | ||
246 | again: | |
247 | len = read(fds[0], &status, 1); | |
248 | if (len == -1 && (errno == EINTR)) | |
249 | goto again; | |
250 | ||
251 | if (len != 1) | |
252 | exit(1); | |
253 | else if (status == 1) { | |
254 | fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno)); | |
255 | exit(1); | |
256 | } else | |
257 | exit(0); | |
258 | } else if (pid < 0) | |
259 | exit(1); | |
260 | ||
261 | close(fds[0]); | |
262 | qemu_set_cloexec(fds[1]); | |
263 | ||
264 | setsid(); | |
265 | ||
266 | pid = fork(); | |
267 | if (pid > 0) | |
268 | exit(0); | |
269 | else if (pid < 0) | |
270 | exit(1); | |
271 | ||
272 | umask(027); | |
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) { | |
285 | uint8_t status = 0; | |
286 | ssize_t len; | |
287 | ||
288 | again1: | |
289 | len = write(fds[1], &status, 1); | |
290 | if (len == -1 && (errno == EINTR)) | |
291 | goto again1; | |
292 | ||
293 | if (len != 1) | |
294 | exit(1); | |
295 | ||
296 | if (chdir("/")) { | |
297 | perror("not able to chdir to /"); | |
298 | exit(1); | |
299 | } | |
300 | TFR(fd = qemu_open("/dev/null", O_RDWR)); | |
301 | if (fd == -1) | |
302 | exit(1); | |
303 | } | |
304 | ||
e06eb601 JS |
305 | change_root(); |
306 | change_process_uid(); | |
eb505be1 JS |
307 | |
308 | if (daemonize) { | |
309 | dup2(fd, 0); | |
310 | dup2(fd, 1); | |
311 | dup2(fd, 2); | |
312 | ||
313 | close(fd); | |
314 | } | |
315 | } | |
316 | ||
317 | void os_pidfile_error(void) | |
318 | { | |
319 | if (daemonize) { | |
320 | uint8_t status = 1; | |
321 | if (write(fds[1], &status, 1) != 1) { | |
322 | perror("daemonize. Writing to pipe\n"); | |
323 | } | |
324 | } else | |
325 | fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno)); | |
326 | } | |
9156d763 JS |
327 | |
328 | void os_set_line_buffering(void) | |
329 | { | |
330 | setvbuf(stdout, NULL, _IOLBF, 0); | |
331 | } |