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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 "qemu/osdep.h" | |
27 | #include <sys/wait.h> | |
28 | /*needed for MAP_POPULATE before including qemu-options.h */ | |
29 | #include <pwd.h> | |
30 | #include <grp.h> | |
31 | #include <libgen.h> | |
32 | ||
33 | /* Needed early for CONFIG_BSD etc. */ | |
34 | #include "sysemu/sysemu.h" | |
35 | #include "net/slirp.h" | |
36 | #include "qemu-options.h" | |
37 | #include "qemu/rcu.h" | |
38 | #include "qemu/error-report.h" | |
39 | #include "qemu/log.h" | |
40 | #include "qemu/cutils.h" | |
41 | ||
42 | #ifdef CONFIG_LINUX | |
43 | #include <sys/prctl.h> | |
44 | #endif | |
45 | ||
46 | static struct passwd *user_pwd; | |
47 | static const char *chroot_dir; | |
48 | static int daemonize; | |
49 | static int daemon_pipe; | |
50 | ||
51 | void os_setup_early_signal_handling(void) | |
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 | } | |
59 | ||
60 | static void termsig_handler(int signal, siginfo_t *info, void *c) | |
61 | { | |
62 | qemu_system_killed(info->si_signo, info->si_pid); | |
63 | } | |
64 | ||
65 | void os_setup_signal_handling(void) | |
66 | { | |
67 | struct sigaction act; | |
68 | ||
69 | memset(&act, 0, sizeof(act)); | |
70 | act.sa_sigaction = termsig_handler; | |
71 | act.sa_flags = SA_SIGINFO; | |
72 | sigaction(SIGINT, &act, NULL); | |
73 | sigaction(SIGHUP, &act, NULL); | |
74 | sigaction(SIGTERM, &act, NULL); | |
75 | } | |
76 | ||
77 | /* Find a likely location for support files using the location of the binary. | |
78 | For installed binaries this will be "$bindir/../share/qemu". When | |
79 | running from the build tree this will be "$bindir/../pc-bios". */ | |
80 | #define SHARE_SUFFIX "/share/qemu" | |
81 | #define BUILD_SUFFIX "/pc-bios" | |
82 | char *os_find_datadir(void) | |
83 | { | |
84 | char *dir, *exec_dir; | |
85 | char *res; | |
86 | size_t max_len; | |
87 | ||
88 | exec_dir = qemu_get_exec_dir(); | |
89 | if (exec_dir == NULL) { | |
90 | return NULL; | |
91 | } | |
92 | dir = g_path_get_dirname(exec_dir); | |
93 | ||
94 | max_len = strlen(dir) + | |
95 | MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1; | |
96 | res = g_malloc0(max_len); | |
97 | snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX); | |
98 | if (access(res, R_OK)) { | |
99 | snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX); | |
100 | if (access(res, R_OK)) { | |
101 | g_free(res); | |
102 | res = NULL; | |
103 | } | |
104 | } | |
105 | ||
106 | g_free(dir); | |
107 | g_free(exec_dir); | |
108 | return res; | |
109 | } | |
110 | #undef SHARE_SUFFIX | |
111 | #undef BUILD_SUFFIX | |
112 | ||
113 | void os_set_proc_name(const char *s) | |
114 | { | |
115 | #if defined(PR_SET_NAME) | |
116 | char name[16]; | |
117 | if (!s) | |
118 | return; | |
119 | pstrcpy(name, sizeof(name), s); | |
120 | /* Could rewrite argv[0] too, but that's a bit more complicated. | |
121 | This simple way is enough for `top'. */ | |
122 | if (prctl(PR_SET_NAME, name)) { | |
123 | perror("unable to change process name"); | |
124 | exit(1); | |
125 | } | |
126 | #else | |
127 | fprintf(stderr, "Change of process name not supported by your OS\n"); | |
128 | exit(1); | |
129 | #endif | |
130 | } | |
131 | ||
132 | /* | |
133 | * Parse OS specific command line options. | |
134 | * return 0 if option handled, -1 otherwise | |
135 | */ | |
136 | void os_parse_cmd_args(int index, const char *optarg) | |
137 | { | |
138 | switch (index) { | |
139 | #ifdef CONFIG_SLIRP | |
140 | case QEMU_OPTION_smb: | |
141 | error_report("The -smb option is deprecated. " | |
142 | "Please use '-netdev user,smb=...' instead."); | |
143 | if (net_slirp_smb(optarg) < 0) | |
144 | exit(1); | |
145 | break; | |
146 | #endif | |
147 | case QEMU_OPTION_runas: | |
148 | user_pwd = getpwnam(optarg); | |
149 | if (!user_pwd) { | |
150 | fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); | |
151 | exit(1); | |
152 | } | |
153 | break; | |
154 | case QEMU_OPTION_chroot: | |
155 | chroot_dir = optarg; | |
156 | break; | |
157 | case QEMU_OPTION_daemonize: | |
158 | daemonize = 1; | |
159 | break; | |
160 | #if defined(CONFIG_LINUX) | |
161 | case QEMU_OPTION_enablefips: | |
162 | fips_set_state(true); | |
163 | break; | |
164 | #endif | |
165 | } | |
166 | } | |
167 | ||
168 | static void change_process_uid(void) | |
169 | { | |
170 | if (user_pwd) { | |
171 | if (setgid(user_pwd->pw_gid) < 0) { | |
172 | fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); | |
173 | exit(1); | |
174 | } | |
175 | if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { | |
176 | fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n", | |
177 | user_pwd->pw_name, user_pwd->pw_gid); | |
178 | exit(1); | |
179 | } | |
180 | if (setuid(user_pwd->pw_uid) < 0) { | |
181 | fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); | |
182 | exit(1); | |
183 | } | |
184 | if (setuid(0) != -1) { | |
185 | fprintf(stderr, "Dropping privileges failed\n"); | |
186 | exit(1); | |
187 | } | |
188 | } | |
189 | } | |
190 | ||
191 | static void change_root(void) | |
192 | { | |
193 | if (chroot_dir) { | |
194 | if (chroot(chroot_dir) < 0) { | |
195 | fprintf(stderr, "chroot failed\n"); | |
196 | exit(1); | |
197 | } | |
198 | if (chdir("/")) { | |
199 | perror("not able to chdir to /"); | |
200 | exit(1); | |
201 | } | |
202 | } | |
203 | ||
204 | } | |
205 | ||
206 | void os_daemonize(void) | |
207 | { | |
208 | if (daemonize) { | |
209 | pid_t pid; | |
210 | int fds[2]; | |
211 | ||
212 | if (pipe(fds) == -1) { | |
213 | exit(1); | |
214 | } | |
215 | ||
216 | pid = fork(); | |
217 | if (pid > 0) { | |
218 | uint8_t status; | |
219 | ssize_t len; | |
220 | ||
221 | close(fds[1]); | |
222 | ||
223 | do { | |
224 | len = read(fds[0], &status, 1); | |
225 | } while (len < 0 && errno == EINTR); | |
226 | ||
227 | /* only exit successfully if our child actually wrote | |
228 | * a one-byte zero to our pipe, upon successful init */ | |
229 | exit(len == 1 && status == 0 ? 0 : 1); | |
230 | ||
231 | } else if (pid < 0) { | |
232 | exit(1); | |
233 | } | |
234 | ||
235 | close(fds[0]); | |
236 | daemon_pipe = fds[1]; | |
237 | qemu_set_cloexec(daemon_pipe); | |
238 | ||
239 | setsid(); | |
240 | ||
241 | pid = fork(); | |
242 | if (pid > 0) { | |
243 | exit(0); | |
244 | } else if (pid < 0) { | |
245 | exit(1); | |
246 | } | |
247 | umask(027); | |
248 | ||
249 | signal(SIGTSTP, SIG_IGN); | |
250 | signal(SIGTTOU, SIG_IGN); | |
251 | signal(SIGTTIN, SIG_IGN); | |
252 | rcu_after_fork(); | |
253 | } | |
254 | } | |
255 | ||
256 | void os_setup_post(void) | |
257 | { | |
258 | int fd = 0; | |
259 | ||
260 | if (daemonize) { | |
261 | if (chdir("/")) { | |
262 | perror("not able to chdir to /"); | |
263 | exit(1); | |
264 | } | |
265 | TFR(fd = qemu_open("/dev/null", O_RDWR)); | |
266 | if (fd == -1) { | |
267 | exit(1); | |
268 | } | |
269 | } | |
270 | ||
271 | change_root(); | |
272 | change_process_uid(); | |
273 | ||
274 | if (daemonize) { | |
275 | uint8_t status = 0; | |
276 | ssize_t len; | |
277 | ||
278 | dup2(fd, 0); | |
279 | dup2(fd, 1); | |
280 | /* In case -D is given do not redirect stderr to /dev/null */ | |
281 | if (!qemu_logfile) { | |
282 | dup2(fd, 2); | |
283 | } | |
284 | ||
285 | close(fd); | |
286 | ||
287 | do { | |
288 | len = write(daemon_pipe, &status, 1); | |
289 | } while (len < 0 && errno == EINTR); | |
290 | if (len != 1) { | |
291 | exit(1); | |
292 | } | |
293 | } | |
294 | } | |
295 | ||
296 | void os_set_line_buffering(void) | |
297 | { | |
298 | setvbuf(stdout, NULL, _IOLBF, 0); | |
299 | } | |
300 | ||
301 | int qemu_create_pidfile(const char *filename) | |
302 | { | |
303 | char buffer[128]; | |
304 | int len; | |
305 | int fd; | |
306 | ||
307 | fd = qemu_open(filename, O_RDWR | O_CREAT, 0600); | |
308 | if (fd == -1) { | |
309 | return -1; | |
310 | } | |
311 | if (lockf(fd, F_TLOCK, 0) == -1) { | |
312 | close(fd); | |
313 | return -1; | |
314 | } | |
315 | len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid()); | |
316 | if (write(fd, buffer, len) != len) { | |
317 | close(fd); | |
318 | return -1; | |
319 | } | |
320 | ||
321 | /* keep pidfile open & locked forever */ | |
322 | return 0; | |
323 | } | |
324 | ||
325 | bool is_daemonized(void) | |
326 | { | |
327 | return daemonize; | |
328 | } | |
329 | ||
330 | int os_mlock(void) | |
331 | { | |
332 | int ret = 0; | |
333 | ||
334 | ret = mlockall(MCL_CURRENT | MCL_FUTURE); | |
335 | if (ret < 0) { | |
336 | perror("mlockall"); | |
337 | } | |
338 | ||
339 | return ret; | |
340 | } |