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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 | ||
d38ea87a | 26 | #include "qemu/osdep.h" |
8d963e6a | 27 | #include <sys/wait.h> |
8847cfe8 | 28 | #include <pwd.h> |
cc4662f9 | 29 | #include <grp.h> |
6170540b | 30 | #include <libgen.h> |
86b645e7 JS |
31 | |
32 | /* Needed early for CONFIG_BSD etc. */ | |
59a5264b | 33 | #include "net/slirp.h" |
f853ac66 | 34 | #include "qemu/error-report.h" |
96c33a45 | 35 | #include "qemu/log.h" |
54d31236 | 36 | #include "sysemu/runstate.h" |
f348b6d1 | 37 | #include "qemu/cutils.h" |
86b645e7 | 38 | |
ce798cf2 JS |
39 | #ifdef CONFIG_LINUX |
40 | #include <sys/prctl.h> | |
949d31e6 JS |
41 | #endif |
42 | ||
2c42f1e8 IJ |
43 | /* |
44 | * Must set all three of these at once. | |
45 | * Legal combinations are unset by name by uid | |
46 | */ | |
47 | static struct passwd *user_pwd; /* NULL non-NULL NULL */ | |
48 | static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */ | |
49 | static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */ | |
50 | ||
0766379d | 51 | static const char *chroot_dir; |
eb505be1 | 52 | static int daemonize; |
0be5e436 | 53 | static int daemon_pipe; |
8847cfe8 | 54 | |
fe98ac14 | 55 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
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 | } | |
8d963e6a | 63 | |
f64622c4 | 64 | static void termsig_handler(int signal, siginfo_t *info, void *c) |
8d963e6a | 65 | { |
f64622c4 | 66 | qemu_system_killed(info->si_signo, info->si_pid); |
8d963e6a JS |
67 | } |
68 | ||
8d963e6a JS |
69 | void os_setup_signal_handling(void) |
70 | { | |
71 | struct sigaction act; | |
72 | ||
73 | memset(&act, 0, sizeof(act)); | |
f64622c4 GN |
74 | act.sa_sigaction = termsig_handler; |
75 | act.sa_flags = SA_SIGINFO; | |
8d963e6a JS |
76 | sigaction(SIGINT, &act, NULL); |
77 | sigaction(SIGHUP, &act, NULL); | |
78 | sigaction(SIGTERM, &act, NULL); | |
8d963e6a | 79 | } |
6170540b | 80 | |
ce798cf2 JS |
81 | void os_set_proc_name(const char *s) |
82 | { | |
83 | #if defined(PR_SET_NAME) | |
84 | char name[16]; | |
85 | if (!s) | |
86 | return; | |
3eadc68e | 87 | pstrcpy(name, sizeof(name), s); |
ce798cf2 JS |
88 | /* Could rewrite argv[0] too, but that's a bit more complicated. |
89 | This simple way is enough for `top'. */ | |
90 | if (prctl(PR_SET_NAME, name)) { | |
a7aaec14 | 91 | error_report("unable to change process name: %s", strerror(errno)); |
ce798cf2 JS |
92 | exit(1); |
93 | } | |
94 | #else | |
22cd4f48 | 95 | error_report("Change of process name not supported by your OS"); |
ce798cf2 JS |
96 | exit(1); |
97 | #endif | |
98 | } | |
99 | ||
22d02515 MT |
100 | /* |
101 | * Prepare to change user ID. optarg can be one of 3 forms: | |
102 | * - a username, in which case user ID will be changed to its uid, | |
103 | * with primary and supplementary groups set up too; | |
104 | * - a numeric uid, in which case only the uid will be set; | |
105 | * - a pair of numeric uid:gid. | |
106 | */ | |
107 | bool os_set_runas(const char *optarg) | |
2c42f1e8 IJ |
108 | { |
109 | unsigned long lv; | |
110 | const char *ep; | |
111 | uid_t got_uid; | |
112 | gid_t got_gid; | |
113 | int rc; | |
114 | ||
22d02515 MT |
115 | user_pwd = getpwnam(optarg); |
116 | if (user_pwd) { | |
117 | user_uid = -1; | |
118 | user_gid = -1; | |
119 | return true; | |
120 | } | |
121 | ||
2c42f1e8 IJ |
122 | rc = qemu_strtoul(optarg, &ep, 0, &lv); |
123 | got_uid = lv; /* overflow here is ID in C99 */ | |
124 | if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) { | |
125 | return false; | |
126 | } | |
127 | ||
128 | rc = qemu_strtoul(ep + 1, 0, 0, &lv); | |
129 | got_gid = lv; /* overflow here is ID in C99 */ | |
130 | if (rc || got_gid != lv || got_gid == (gid_t)-1) { | |
131 | return false; | |
132 | } | |
133 | ||
134 | user_pwd = NULL; | |
135 | user_uid = got_uid; | |
136 | user_gid = got_gid; | |
137 | return true; | |
138 | } | |
139 | ||
e06eb601 | 140 | static void change_process_uid(void) |
8847cfe8 | 141 | { |
2c42f1e8 IJ |
142 | assert((user_uid == (uid_t)-1) || user_pwd == NULL); |
143 | assert((user_uid == (uid_t)-1) == | |
144 | (user_gid == (gid_t)-1)); | |
145 | ||
146 | if (user_pwd || user_uid != (uid_t)-1) { | |
147 | gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid; | |
148 | uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid; | |
149 | if (setgid(intended_gid) < 0) { | |
150 | error_report("Failed to setgid(%d)", intended_gid); | |
8847cfe8 JS |
151 | exit(1); |
152 | } | |
2c42f1e8 IJ |
153 | if (user_pwd) { |
154 | if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { | |
155 | error_report("Failed to initgroups(\"%s\", %d)", | |
156 | user_pwd->pw_name, user_pwd->pw_gid); | |
157 | exit(1); | |
158 | } | |
159 | } else { | |
160 | if (setgroups(1, &user_gid) < 0) { | |
161 | error_report("Failed to setgroups(1, [%d])", | |
162 | user_gid); | |
163 | exit(1); | |
164 | } | |
cc4662f9 | 165 | } |
2c42f1e8 IJ |
166 | if (setuid(intended_uid) < 0) { |
167 | error_report("Failed to setuid(%d)", intended_uid); | |
8847cfe8 JS |
168 | exit(1); |
169 | } | |
170 | if (setuid(0) != -1) { | |
f0a2171b | 171 | error_report("Dropping privileges failed"); |
8847cfe8 JS |
172 | exit(1); |
173 | } | |
174 | } | |
175 | } | |
0766379d | 176 | |
5b156390 MT |
177 | void os_set_chroot(const char *optarg) |
178 | { | |
179 | chroot_dir = optarg; | |
180 | } | |
181 | ||
e06eb601 | 182 | static void change_root(void) |
0766379d JS |
183 | { |
184 | if (chroot_dir) { | |
185 | if (chroot(chroot_dir) < 0) { | |
22cd4f48 | 186 | error_report("chroot failed"); |
0766379d JS |
187 | exit(1); |
188 | } | |
189 | if (chdir("/")) { | |
a7aaec14 | 190 | error_report("not able to chdir to /: %s", strerror(errno)); |
0766379d JS |
191 | exit(1); |
192 | } | |
193 | } | |
194 | ||
195 | } | |
eb505be1 JS |
196 | |
197 | void os_daemonize(void) | |
198 | { | |
199 | if (daemonize) { | |
63ce8e15 | 200 | pid_t pid; |
0be5e436 | 201 | int fds[2]; |
eb505be1 | 202 | |
3338a41f | 203 | if (!g_unix_open_pipe(fds, FD_CLOEXEC, NULL)) { |
63ce8e15 GA |
204 | exit(1); |
205 | } | |
eb505be1 | 206 | |
63ce8e15 GA |
207 | pid = fork(); |
208 | if (pid > 0) { | |
209 | uint8_t status; | |
210 | ssize_t len; | |
eb505be1 | 211 | |
63ce8e15 | 212 | close(fds[1]); |
eb505be1 | 213 | |
ccea25f1 MT |
214 | do { |
215 | len = read(fds[0], &status, 1); | |
216 | } while (len < 0 && errno == EINTR); | |
fee78fd6 MT |
217 | |
218 | /* only exit successfully if our child actually wrote | |
219 | * a one-byte zero to our pipe, upon successful init */ | |
220 | exit(len == 1 && status == 0 ? 0 : 1); | |
221 | ||
222 | } else if (pid < 0) { | |
223 | exit(1); | |
224 | } | |
eb505be1 | 225 | |
63ce8e15 | 226 | close(fds[0]); |
0be5e436 | 227 | daemon_pipe = fds[1]; |
eb505be1 | 228 | |
63ce8e15 | 229 | setsid(); |
eb505be1 | 230 | |
63ce8e15 GA |
231 | pid = fork(); |
232 | if (pid > 0) { | |
233 | exit(0); | |
234 | } else if (pid < 0) { | |
235 | exit(1); | |
236 | } | |
237 | umask(027); | |
eb505be1 JS |
238 | |
239 | signal(SIGTSTP, SIG_IGN); | |
240 | signal(SIGTTOU, SIG_IGN); | |
241 | signal(SIGTTIN, SIG_IGN); | |
242 | } | |
243 | } | |
244 | ||
245 | void os_setup_post(void) | |
246 | { | |
247 | int fd = 0; | |
248 | ||
249 | if (daemonize) { | |
eb505be1 | 250 | if (chdir("/")) { |
a7aaec14 | 251 | error_report("not able to chdir to /: %s", strerror(errno)); |
eb505be1 JS |
252 | exit(1); |
253 | } | |
8b6aa693 | 254 | fd = RETRY_ON_EINTR(qemu_open_old("/dev/null", O_RDWR)); |
63ce8e15 GA |
255 | if (fd == -1) { |
256 | exit(1); | |
257 | } | |
eb505be1 JS |
258 | } |
259 | ||
e06eb601 JS |
260 | change_root(); |
261 | change_process_uid(); | |
eb505be1 JS |
262 | |
263 | if (daemonize) { | |
25cec2b8 MT |
264 | uint8_t status = 0; |
265 | ssize_t len; | |
266 | ||
eb505be1 JS |
267 | dup2(fd, 0); |
268 | dup2(fd, 1); | |
96c33a45 | 269 | /* In case -D is given do not redirect stderr to /dev/null */ |
229ef2eb | 270 | if (!qemu_log_enabled()) { |
96c33a45 DA |
271 | dup2(fd, 2); |
272 | } | |
eb505be1 JS |
273 | |
274 | close(fd); | |
25cec2b8 MT |
275 | |
276 | do { | |
277 | len = write(daemon_pipe, &status, 1); | |
278 | } while (len < 0 && errno == EINTR); | |
279 | if (len != 1) { | |
280 | exit(1); | |
281 | } | |
eb505be1 JS |
282 | } |
283 | } | |
284 | ||
9156d763 JS |
285 | void os_set_line_buffering(void) |
286 | { | |
287 | setvbuf(stdout, NULL, _IOLBF, 0); | |
288 | } | |
949d31e6 | 289 | |
995ee2bf HM |
290 | bool is_daemonized(void) |
291 | { | |
292 | return daemonize; | |
293 | } | |
888a6bc6 | 294 | |
f22ac472 HR |
295 | int os_set_daemonize(bool d) |
296 | { | |
297 | daemonize = d; | |
298 | return 0; | |
299 | } | |
300 | ||
888a6bc6 SM |
301 | int os_mlock(void) |
302 | { | |
195588cc | 303 | #ifdef HAVE_MLOCKALL |
888a6bc6 SM |
304 | int ret = 0; |
305 | ||
306 | ret = mlockall(MCL_CURRENT | MCL_FUTURE); | |
307 | if (ret < 0) { | |
a7aaec14 | 308 | error_report("mlockall: %s", strerror(errno)); |
888a6bc6 SM |
309 | } |
310 | ||
311 | return ret; | |
195588cc DC |
312 | #else |
313 | return -ENOSYS; | |
314 | #endif | |
888a6bc6 | 315 | } |