quorum: Inline quorum_aio_cb()
[qemu.git] / os-posix.c
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 }