root / os-posix.c @ cbcc6336
History | View | Annotate | Download (8.5 kB)
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> |
29 |
#include <sys/types.h> |
30 |
#include <sys/wait.h> |
31 |
/*needed for MAP_POPULATE before including qemu-options.h */
|
32 |
#include <sys/mman.h> |
33 |
#include <pwd.h> |
34 |
#include <libgen.h> |
35 |
|
36 |
/* Needed early for CONFIG_BSD etc. */
|
37 |
#include "config-host.h" |
38 |
#include "sysemu.h" |
39 |
#include "net/slirp.h" |
40 |
#include "qemu-options.h" |
41 |
|
42 |
#ifdef CONFIG_LINUX
|
43 |
#include <sys/prctl.h> |
44 |
#endif
|
45 |
|
46 |
#ifdef CONFIG_EVENTFD
|
47 |
#include <sys/eventfd.h> |
48 |
#endif
|
49 |
|
50 |
static struct passwd *user_pwd; |
51 |
static const char *chroot_dir; |
52 |
static int daemonize; |
53 |
static int fds[2]; |
54 |
|
55 |
void os_setup_early_signal_handling(void) |
56 |
{ |
57 |
struct sigaction act;
|
58 |
sigfillset(&act.sa_mask); |
59 |
act.sa_flags = 0;
|
60 |
act.sa_handler = SIG_IGN; |
61 |
sigaction(SIGPIPE, &act, NULL);
|
62 |
} |
63 |
|
64 |
static void termsig_handler(int signal) |
65 |
{ |
66 |
qemu_system_shutdown_request(); |
67 |
} |
68 |
|
69 |
static void sigchld_handler(int signal) |
70 |
{ |
71 |
waitpid(-1, NULL, WNOHANG); |
72 |
} |
73 |
|
74 |
void os_setup_signal_handling(void) |
75 |
{ |
76 |
struct sigaction act;
|
77 |
|
78 |
memset(&act, 0, sizeof(act)); |
79 |
act.sa_handler = termsig_handler; |
80 |
sigaction(SIGINT, &act, NULL);
|
81 |
sigaction(SIGHUP, &act, NULL);
|
82 |
sigaction(SIGTERM, &act, NULL);
|
83 |
|
84 |
act.sa_handler = sigchld_handler; |
85 |
act.sa_flags = SA_NOCLDSTOP; |
86 |
sigaction(SIGCHLD, &act, NULL);
|
87 |
} |
88 |
|
89 |
/* Find a likely location for support files using the location of the binary.
|
90 |
For installed binaries this will be "$bindir/../share/qemu". When
|
91 |
running from the build tree this will be "$bindir/../pc-bios". */
|
92 |
#define SHARE_SUFFIX "/share/qemu" |
93 |
#define BUILD_SUFFIX "/pc-bios" |
94 |
char *os_find_datadir(const char *argv0) |
95 |
{ |
96 |
char *dir;
|
97 |
char *p = NULL; |
98 |
char *res;
|
99 |
char buf[PATH_MAX];
|
100 |
size_t max_len; |
101 |
|
102 |
#if defined(__linux__)
|
103 |
{ |
104 |
int len;
|
105 |
len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); |
106 |
if (len > 0) { |
107 |
buf[len] = 0;
|
108 |
p = buf; |
109 |
} |
110 |
} |
111 |
#elif defined(__FreeBSD__)
|
112 |
{ |
113 |
static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; |
114 |
size_t len = sizeof(buf) - 1; |
115 |
|
116 |
*buf = '\0';
|
117 |
if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && |
118 |
*buf) { |
119 |
buf[sizeof(buf) - 1] = '\0'; |
120 |
p = buf; |
121 |
} |
122 |
} |
123 |
#endif
|
124 |
/* If we don't have any way of figuring out the actual executable
|
125 |
location then try argv[0]. */
|
126 |
if (!p) {
|
127 |
p = realpath(argv0, buf); |
128 |
if (!p) {
|
129 |
return NULL; |
130 |
} |
131 |
} |
132 |
dir = dirname(p); |
133 |
dir = dirname(dir); |
134 |
|
135 |
max_len = strlen(dir) + |
136 |
MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1;
|
137 |
res = qemu_mallocz(max_len); |
138 |
snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX);
|
139 |
if (access(res, R_OK)) {
|
140 |
snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX);
|
141 |
if (access(res, R_OK)) {
|
142 |
qemu_free(res); |
143 |
res = NULL;
|
144 |
} |
145 |
} |
146 |
|
147 |
return res;
|
148 |
} |
149 |
#undef SHARE_SUFFIX
|
150 |
#undef BUILD_SUFFIX
|
151 |
|
152 |
void os_set_proc_name(const char *s) |
153 |
{ |
154 |
#if defined(PR_SET_NAME)
|
155 |
char name[16]; |
156 |
if (!s)
|
157 |
return;
|
158 |
name[sizeof(name) - 1] = 0; |
159 |
strncpy(name, s, sizeof(name));
|
160 |
/* Could rewrite argv[0] too, but that's a bit more complicated.
|
161 |
This simple way is enough for `top'. */
|
162 |
if (prctl(PR_SET_NAME, name)) {
|
163 |
perror("unable to change process name");
|
164 |
exit(1);
|
165 |
} |
166 |
#else
|
167 |
fprintf(stderr, "Change of process name not supported by your OS\n");
|
168 |
exit(1);
|
169 |
#endif
|
170 |
} |
171 |
|
172 |
/*
|
173 |
* Parse OS specific command line options.
|
174 |
* return 0 if option handled, -1 otherwise
|
175 |
*/
|
176 |
void os_parse_cmd_args(int index, const char *optarg) |
177 |
{ |
178 |
switch (index) {
|
179 |
#ifdef CONFIG_SLIRP
|
180 |
case QEMU_OPTION_smb:
|
181 |
if (net_slirp_smb(optarg) < 0) |
182 |
exit(1);
|
183 |
break;
|
184 |
#endif
|
185 |
case QEMU_OPTION_runas:
|
186 |
user_pwd = getpwnam(optarg); |
187 |
if (!user_pwd) {
|
188 |
fprintf(stderr, "User \"%s\" doesn't exist\n", optarg);
|
189 |
exit(1);
|
190 |
} |
191 |
break;
|
192 |
case QEMU_OPTION_chroot:
|
193 |
chroot_dir = optarg; |
194 |
break;
|
195 |
case QEMU_OPTION_daemonize:
|
196 |
daemonize = 1;
|
197 |
break;
|
198 |
} |
199 |
return;
|
200 |
} |
201 |
|
202 |
static void change_process_uid(void) |
203 |
{ |
204 |
if (user_pwd) {
|
205 |
if (setgid(user_pwd->pw_gid) < 0) { |
206 |
fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid);
|
207 |
exit(1);
|
208 |
} |
209 |
if (setuid(user_pwd->pw_uid) < 0) { |
210 |
fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid);
|
211 |
exit(1);
|
212 |
} |
213 |
if (setuid(0) != -1) { |
214 |
fprintf(stderr, "Dropping privileges failed\n");
|
215 |
exit(1);
|
216 |
} |
217 |
} |
218 |
} |
219 |
|
220 |
static void change_root(void) |
221 |
{ |
222 |
if (chroot_dir) {
|
223 |
if (chroot(chroot_dir) < 0) { |
224 |
fprintf(stderr, "chroot failed\n");
|
225 |
exit(1);
|
226 |
} |
227 |
if (chdir("/")) { |
228 |
perror("not able to chdir to /");
|
229 |
exit(1);
|
230 |
} |
231 |
} |
232 |
|
233 |
} |
234 |
|
235 |
void os_daemonize(void) |
236 |
{ |
237 |
if (daemonize) {
|
238 |
pid_t pid; |
239 |
|
240 |
if (pipe(fds) == -1) |
241 |
exit(1);
|
242 |
|
243 |
pid = fork(); |
244 |
if (pid > 0) { |
245 |
uint8_t status; |
246 |
ssize_t len; |
247 |
|
248 |
close(fds[1]);
|
249 |
|
250 |
again:
|
251 |
len = read(fds[0], &status, 1); |
252 |
if (len == -1 && (errno == EINTR)) |
253 |
goto again;
|
254 |
|
255 |
if (len != 1) |
256 |
exit(1);
|
257 |
else if (status == 1) { |
258 |
fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno));
|
259 |
exit(1);
|
260 |
} else
|
261 |
exit(0);
|
262 |
} else if (pid < 0) |
263 |
exit(1);
|
264 |
|
265 |
close(fds[0]);
|
266 |
qemu_set_cloexec(fds[1]);
|
267 |
|
268 |
setsid(); |
269 |
|
270 |
pid = fork(); |
271 |
if (pid > 0) |
272 |
exit(0);
|
273 |
else if (pid < 0) |
274 |
exit(1);
|
275 |
|
276 |
umask(027);
|
277 |
|
278 |
signal(SIGTSTP, SIG_IGN); |
279 |
signal(SIGTTOU, SIG_IGN); |
280 |
signal(SIGTTIN, SIG_IGN); |
281 |
} |
282 |
} |
283 |
|
284 |
void os_setup_post(void) |
285 |
{ |
286 |
int fd = 0; |
287 |
|
288 |
if (daemonize) {
|
289 |
uint8_t status = 0;
|
290 |
ssize_t len; |
291 |
|
292 |
again1:
|
293 |
len = write(fds[1], &status, 1); |
294 |
if (len == -1 && (errno == EINTR)) |
295 |
goto again1;
|
296 |
|
297 |
if (len != 1) |
298 |
exit(1);
|
299 |
|
300 |
if (chdir("/")) { |
301 |
perror("not able to chdir to /");
|
302 |
exit(1);
|
303 |
} |
304 |
TFR(fd = qemu_open("/dev/null", O_RDWR));
|
305 |
if (fd == -1) |
306 |
exit(1);
|
307 |
} |
308 |
|
309 |
change_root(); |
310 |
change_process_uid(); |
311 |
|
312 |
if (daemonize) {
|
313 |
dup2(fd, 0);
|
314 |
dup2(fd, 1);
|
315 |
dup2(fd, 2);
|
316 |
|
317 |
close(fd); |
318 |
} |
319 |
} |
320 |
|
321 |
void os_pidfile_error(void) |
322 |
{ |
323 |
if (daemonize) {
|
324 |
uint8_t status = 1;
|
325 |
if (write(fds[1], &status, 1) != 1) { |
326 |
perror("daemonize. Writing to pipe\n");
|
327 |
} |
328 |
} else
|
329 |
fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno));
|
330 |
} |
331 |
|
332 |
void os_set_line_buffering(void) |
333 |
{ |
334 |
setvbuf(stdout, NULL, _IOLBF, 0); |
335 |
} |
336 |
|
337 |
/*
|
338 |
* Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set.
|
339 |
*/
|
340 |
int qemu_eventfd(int fds[2]) |
341 |
{ |
342 |
#ifdef CONFIG_EVENTFD
|
343 |
int ret;
|
344 |
|
345 |
ret = eventfd(0, 0); |
346 |
if (ret >= 0) { |
347 |
fds[0] = ret;
|
348 |
qemu_set_cloexec(ret); |
349 |
if ((fds[1] = dup(ret)) == -1) { |
350 |
close(ret); |
351 |
return -1; |
352 |
} |
353 |
qemu_set_cloexec(fds[1]);
|
354 |
return 0; |
355 |
} |
356 |
|
357 |
if (errno != ENOSYS) {
|
358 |
return -1; |
359 |
} |
360 |
#endif
|
361 |
|
362 |
return qemu_pipe(fds);
|
363 |
} |
364 |
|
365 |
int qemu_create_pidfile(const char *filename) |
366 |
{ |
367 |
char buffer[128]; |
368 |
int len;
|
369 |
int fd;
|
370 |
|
371 |
fd = qemu_open(filename, O_RDWR | O_CREAT, 0600);
|
372 |
if (fd == -1) { |
373 |
return -1; |
374 |
} |
375 |
if (lockf(fd, F_TLOCK, 0) == -1) { |
376 |
return -1; |
377 |
} |
378 |
len = snprintf(buffer, sizeof(buffer), "%ld\n", (long)getpid()); |
379 |
if (write(fd, buffer, len) != len) {
|
380 |
return -1; |
381 |
} |
382 |
|
383 |
return 0; |
384 |
} |