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86b645e Introduce os-posix.c and create os_setup_signal_handling()
Jes Sorensen authored
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>
8d963e6 Move main signal handler setup to os specificfiles.
Jes Sorensen authored
29 #include <sys/types.h>
30 #include <sys/wait.h>
69e8b16 Include sys/mman.h before qemu-options.h
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31 /*needed for MAP_POPULATE before including qemu-options.h */
32 #include <sys/mman.h>
8847cfe Move runas handling from vl.c to OS specific files.
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33 #include <pwd.h>
6170540 Move find_datadir to OS specific files.
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34 #include <libgen.h>
86b645e Introduce os-posix.c and create os_setup_signal_handling()
Jes Sorensen authored
35
36 /* Needed early for CONFIG_BSD etc. */
37 #include "config-host.h"
38 #include "sysemu.h"
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39 #include "net/slirp.h"
40 #include "qemu-options.h"
86b645e Introduce os-posix.c and create os_setup_signal_handling()
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41
ce798cf Move set_proc_name() to OS specific files.
Jes Sorensen authored
42 #ifdef CONFIG_LINUX
43 #include <sys/prctl.h>
44 #endif
45
8847cfe Move runas handling from vl.c to OS specific files.
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46 static struct passwd *user_pwd;
0766379 Move chroot handling to OS specific files.
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47 static const char *chroot_dir;
eb505be Move daemonize handling to OS specific files
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48 static int daemonize;
49 static int fds[2];
8847cfe Move runas handling from vl.c to OS specific files.
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50
fe98ac1 Rename os_setup_signal_handling() to os_setup_early_signal_handling()
Jes Sorensen authored
51 void os_setup_early_signal_handling(void)
86b645e Introduce os-posix.c and create os_setup_signal_handling()
Jes Sorensen authored
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 }
8d963e6 Move main signal handler setup to os specificfiles.
Jes Sorensen authored
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 }
6170540 Move find_datadir to OS specific files.
Jes Sorensen authored
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
59a5264 Introduce OS specific cmdline argument handling and move SMB arg to o…
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147
ce798cf Move set_proc_name() to OS specific files.
Jes Sorensen authored
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
59a5264 Introduce OS specific cmdline argument handling and move SMB arg to o…
Jes Sorensen authored
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
8847cfe Move runas handling from vl.c to OS specific files.
Jes Sorensen authored
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;
0766379 Move chroot handling to OS specific files.
Jes Sorensen authored
188 case QEMU_OPTION_chroot:
189 chroot_dir = optarg;
190 break;
eb505be Move daemonize handling to OS specific files
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191 case QEMU_OPTION_daemonize:
192 daemonize = 1;
193 break;
59a5264 Introduce OS specific cmdline argument handling and move SMB arg to o…
Jes Sorensen authored
194 }
195 return;
196 }
8847cfe Move runas handling from vl.c to OS specific files.
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197
e06eb60 Make os_change_process_uid and os_change_root os-posix.c local
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198 static void change_process_uid(void)
8847cfe Move runas handling from vl.c to OS specific files.
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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 }
0766379 Move chroot handling to OS specific files.
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215
e06eb60 Make os_change_process_uid and os_change_root os-posix.c local
Jes Sorensen authored
216 static void change_root(void)
0766379 Move chroot handling to OS specific files.
Jes Sorensen authored
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 }
eb505be Move daemonize handling to OS specific files
Jes Sorensen authored
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
e06eb60 Make os_change_process_uid and os_change_root os-posix.c local
Jes Sorensen authored
305 change_root();
306 change_process_uid();
eb505be Move daemonize handling to OS specific files
Jes Sorensen authored
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 }
9156d76 Move line-buffering setup to OS specific files.
Jes Sorensen authored
327
328 void os_set_line_buffering(void)
329 {
330 setvbuf(stdout, NULL, _IOLBF, 0);
331 }
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