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26#include "qemu/osdep.h"
27#include <sys/wait.h>
28#include <pwd.h>
29#include <grp.h>
30#include <libgen.h>
31
32
33#include "sysemu/sysemu.h"
34#include "net/slirp.h"
35#include "qemu-options.h"
36#include "qemu/error-report.h"
37#include "qemu/log.h"
38#include "qemu/cutils.h"
39
40#ifdef CONFIG_LINUX
41#include <sys/prctl.h>
42#endif
43
44
45
46
47
48static struct passwd *user_pwd;
49static uid_t user_uid = (uid_t)-1;
50static gid_t user_gid = (gid_t)-1;
51
52static const char *chroot_dir;
53static int daemonize;
54static int daemon_pipe;
55
56void os_setup_early_signal_handling(void)
57{
58 struct sigaction act;
59 sigfillset(&act.sa_mask);
60 act.sa_flags = 0;
61 act.sa_handler = SIG_IGN;
62 sigaction(SIGPIPE, &act, NULL);
63}
64
65static void termsig_handler(int signal, siginfo_t *info, void *c)
66{
67 qemu_system_killed(info->si_signo, info->si_pid);
68}
69
70void os_setup_signal_handling(void)
71{
72 struct sigaction act;
73
74 memset(&act, 0, sizeof(act));
75 act.sa_sigaction = termsig_handler;
76 act.sa_flags = SA_SIGINFO;
77 sigaction(SIGINT, &act, NULL);
78 sigaction(SIGHUP, &act, NULL);
79 sigaction(SIGTERM, &act, NULL);
80}
81
82
83
84
85#define SHARE_SUFFIX "/share/qemu"
86#define BUILD_SUFFIX "/pc-bios"
87char *os_find_datadir(void)
88{
89 char *dir, *exec_dir;
90 char *res;
91 size_t max_len;
92
93 exec_dir = qemu_get_exec_dir();
94 if (exec_dir == NULL) {
95 return NULL;
96 }
97 dir = g_path_get_dirname(exec_dir);
98
99 max_len = strlen(dir) +
100 MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1;
101 res = g_malloc0(max_len);
102 snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX);
103 if (access(res, R_OK)) {
104 snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX);
105 if (access(res, R_OK)) {
106 g_free(res);
107 res = NULL;
108 }
109 }
110
111 g_free(dir);
112 g_free(exec_dir);
113 return res;
114}
115#undef SHARE_SUFFIX
116#undef BUILD_SUFFIX
117
118void os_set_proc_name(const char *s)
119{
120#if defined(PR_SET_NAME)
121 char name[16];
122 if (!s)
123 return;
124 pstrcpy(name, sizeof(name), s);
125
126
127 if (prctl(PR_SET_NAME, name)) {
128 error_report("unable to change process name: %s", strerror(errno));
129 exit(1);
130 }
131#else
132 error_report("Change of process name not supported by your OS");
133 exit(1);
134#endif
135}
136
137
138static bool os_parse_runas_uid_gid(const char *optarg)
139{
140 unsigned long lv;
141 const char *ep;
142 uid_t got_uid;
143 gid_t got_gid;
144 int rc;
145
146 rc = qemu_strtoul(optarg, &ep, 0, &lv);
147 got_uid = lv;
148 if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) {
149 return false;
150 }
151
152 rc = qemu_strtoul(ep + 1, 0, 0, &lv);
153 got_gid = lv;
154 if (rc || got_gid != lv || got_gid == (gid_t)-1) {
155 return false;
156 }
157
158 user_pwd = NULL;
159 user_uid = got_uid;
160 user_gid = got_gid;
161 return true;
162}
163
164
165
166
167
168int os_parse_cmd_args(int index, const char *optarg)
169{
170 switch (index) {
171#ifdef CONFIG_SLIRP
172 case QEMU_OPTION_smb:
173 error_report("The -smb option is deprecated. "
174 "Please use '-netdev user,smb=...' instead.");
175 if (net_slirp_smb(optarg) < 0)
176 exit(1);
177 break;
178#endif
179 case QEMU_OPTION_runas:
180 user_pwd = getpwnam(optarg);
181 if (user_pwd) {
182 user_uid = -1;
183 user_gid = -1;
184 } else if (!os_parse_runas_uid_gid(optarg)) {
185 error_report("User \"%s\" doesn't exist"
186 " (and is not <uid>:<gid>)",
187 optarg);
188 exit(1);
189 }
190 break;
191 case QEMU_OPTION_chroot:
192 chroot_dir = optarg;
193 break;
194 case QEMU_OPTION_daemonize:
195 daemonize = 1;
196 break;
197#if defined(CONFIG_LINUX)
198 case QEMU_OPTION_enablefips:
199 fips_set_state(true);
200 break;
201#endif
202 default:
203 return -1;
204 }
205
206 return 0;
207}
208
209static void change_process_uid(void)
210{
211 assert((user_uid == (uid_t)-1) || user_pwd == NULL);
212 assert((user_uid == (uid_t)-1) ==
213 (user_gid == (gid_t)-1));
214
215 if (user_pwd || user_uid != (uid_t)-1) {
216 gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid;
217 uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid;
218 if (setgid(intended_gid) < 0) {
219 error_report("Failed to setgid(%d)", intended_gid);
220 exit(1);
221 }
222 if (user_pwd) {
223 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
224 error_report("Failed to initgroups(\"%s\", %d)",
225 user_pwd->pw_name, user_pwd->pw_gid);
226 exit(1);
227 }
228 } else {
229 if (setgroups(1, &user_gid) < 0) {
230 error_report("Failed to setgroups(1, [%d])",
231 user_gid);
232 exit(1);
233 }
234 }
235 if (setuid(intended_uid) < 0) {
236 error_report("Failed to setuid(%d)", intended_uid);
237 exit(1);
238 }
239 if (setuid(0) != -1) {
240 error_report("Dropping privileges failed");
241 exit(1);
242 }
243 }
244}
245
246static void change_root(void)
247{
248 if (chroot_dir) {
249 if (chroot(chroot_dir) < 0) {
250 error_report("chroot failed");
251 exit(1);
252 }
253 if (chdir("/")) {
254 error_report("not able to chdir to /: %s", strerror(errno));
255 exit(1);
256 }
257 }
258
259}
260
261void os_daemonize(void)
262{
263 if (daemonize) {
264 pid_t pid;
265 int fds[2];
266
267 if (pipe(fds) == -1) {
268 exit(1);
269 }
270
271 pid = fork();
272 if (pid > 0) {
273 uint8_t status;
274 ssize_t len;
275
276 close(fds[1]);
277
278 do {
279 len = read(fds[0], &status, 1);
280 } while (len < 0 && errno == EINTR);
281
282
283
284 exit(len == 1 && status == 0 ? 0 : 1);
285
286 } else if (pid < 0) {
287 exit(1);
288 }
289
290 close(fds[0]);
291 daemon_pipe = fds[1];
292 qemu_set_cloexec(daemon_pipe);
293
294 setsid();
295
296 pid = fork();
297 if (pid > 0) {
298 exit(0);
299 } else if (pid < 0) {
300 exit(1);
301 }
302 umask(027);
303
304 signal(SIGTSTP, SIG_IGN);
305 signal(SIGTTOU, SIG_IGN);
306 signal(SIGTTIN, SIG_IGN);
307 }
308}
309
310void os_setup_post(void)
311{
312 int fd = 0;
313
314 if (daemonize) {
315 if (chdir("/")) {
316 error_report("not able to chdir to /: %s", strerror(errno));
317 exit(1);
318 }
319 TFR(fd = qemu_open("/dev/null", O_RDWR));
320 if (fd == -1) {
321 exit(1);
322 }
323 }
324
325 change_root();
326 change_process_uid();
327
328 if (daemonize) {
329 uint8_t status = 0;
330 ssize_t len;
331
332 dup2(fd, 0);
333 dup2(fd, 1);
334
335 if (!qemu_logfile) {
336 dup2(fd, 2);
337 }
338
339 close(fd);
340
341 do {
342 len = write(daemon_pipe, &status, 1);
343 } while (len < 0 && errno == EINTR);
344 if (len != 1) {
345 exit(1);
346 }
347 }
348}
349
350void os_set_line_buffering(void)
351{
352 setvbuf(stdout, NULL, _IOLBF, 0);
353}
354
355int qemu_create_pidfile(const char *filename)
356{
357 char buffer[128];
358 int len;
359 int fd;
360
361 fd = qemu_open(filename, O_RDWR | O_CREAT, 0600);
362 if (fd == -1) {
363 return -1;
364 }
365 if (lockf(fd, F_TLOCK, 0) == -1) {
366 close(fd);
367 return -1;
368 }
369 len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid());
370 if (write(fd, buffer, len) != len) {
371 close(fd);
372 return -1;
373 }
374
375
376 return 0;
377}
378
379bool is_daemonized(void)
380{
381 return daemonize;
382}
383
384int os_mlock(void)
385{
386 int ret = 0;
387
388 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
389 if (ret < 0) {
390 error_report("mlockall: %s", strerror(errno));
391 }
392
393 return ret;
394}
395