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