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Commit | Line | Data |
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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 | 31 | |
a8d25326 | 32 | #include "qemu-common.h" |
86b645e7 | 33 | /* Needed early for CONFIG_BSD etc. */ |
59a5264b JS |
34 | #include "net/slirp.h" |
35 | #include "qemu-options.h" | |
f853ac66 | 36 | #include "qemu/error-report.h" |
96c33a45 | 37 | #include "qemu/log.h" |
54d31236 | 38 | #include "sysemu/runstate.h" |
f348b6d1 | 39 | #include "qemu/cutils.h" |
86b645e7 | 40 | |
ce798cf2 JS |
41 | #ifdef CONFIG_LINUX |
42 | #include <sys/prctl.h> | |
949d31e6 JS |
43 | #endif |
44 | ||
2c42f1e8 IJ |
45 | /* |
46 | * Must set all three of these at once. | |
47 | * Legal combinations are unset by name by uid | |
48 | */ | |
49 | static struct passwd *user_pwd; /* NULL non-NULL NULL */ | |
50 | static uid_t user_uid = (uid_t)-1; /* -1 -1 >=0 */ | |
51 | static gid_t user_gid = (gid_t)-1; /* -1 -1 >=0 */ | |
52 | ||
0766379d | 53 | static const char *chroot_dir; |
eb505be1 | 54 | static int daemonize; |
0be5e436 | 55 | static int daemon_pipe; |
8847cfe8 | 56 | |
fe98ac14 | 57 | void os_setup_early_signal_handling(void) |
86b645e7 JS |
58 | { |
59 | struct sigaction act; | |
60 | sigfillset(&act.sa_mask); | |
61 | act.sa_flags = 0; | |
62 | act.sa_handler = SIG_IGN; | |
63 | sigaction(SIGPIPE, &act, NULL); | |
64 | } | |
8d963e6a | 65 | |
f64622c4 | 66 | static void termsig_handler(int signal, siginfo_t *info, void *c) |
8d963e6a | 67 | { |
f64622c4 | 68 | qemu_system_killed(info->si_signo, info->si_pid); |
8d963e6a JS |
69 | } |
70 | ||
8d963e6a JS |
71 | void os_setup_signal_handling(void) |
72 | { | |
73 | struct sigaction act; | |
74 | ||
75 | memset(&act, 0, sizeof(act)); | |
f64622c4 GN |
76 | act.sa_sigaction = termsig_handler; |
77 | act.sa_flags = SA_SIGINFO; | |
8d963e6a JS |
78 | sigaction(SIGINT, &act, NULL); |
79 | sigaction(SIGHUP, &act, NULL); | |
80 | sigaction(SIGTERM, &act, NULL); | |
8d963e6a | 81 | } |
6170540b | 82 | |
6dd2dace MAL |
83 | /* |
84 | * Find a likely location for support files using the location of the binary. | |
85 | * When running from the build tree this will be "$bindir/../pc-bios". | |
86 | * Otherwise, this is CONFIG_QEMU_DATADIR. | |
87 | */ | |
10f5bff6 | 88 | char *os_find_datadir(void) |
6170540b | 89 | { |
6dd2dace MAL |
90 | g_autofree char *exec_dir = NULL; |
91 | g_autofree char *dir = NULL; | |
6170540b | 92 | |
10f5bff6 | 93 | exec_dir = qemu_get_exec_dir(); |
6dd2dace MAL |
94 | g_return_val_if_fail(exec_dir != NULL, NULL); |
95 | ||
96 | dir = g_build_filename(exec_dir, "..", "pc-bios", NULL); | |
97 | if (g_file_test(dir, G_FILE_TEST_IS_DIR)) { | |
98 | return g_steal_pointer(&dir); | |
6170540b JS |
99 | } |
100 | ||
6dd2dace | 101 | return g_strdup(CONFIG_QEMU_DATADIR); |
6170540b | 102 | } |
59a5264b | 103 | |
ce798cf2 JS |
104 | void os_set_proc_name(const char *s) |
105 | { | |
106 | #if defined(PR_SET_NAME) | |
107 | char name[16]; | |
108 | if (!s) | |
109 | return; | |
3eadc68e | 110 | pstrcpy(name, sizeof(name), s); |
ce798cf2 JS |
111 | /* Could rewrite argv[0] too, but that's a bit more complicated. |
112 | This simple way is enough for `top'. */ | |
113 | if (prctl(PR_SET_NAME, name)) { | |
a7aaec14 | 114 | error_report("unable to change process name: %s", strerror(errno)); |
ce798cf2 JS |
115 | exit(1); |
116 | } | |
117 | #else | |
22cd4f48 | 118 | error_report("Change of process name not supported by your OS"); |
ce798cf2 JS |
119 | exit(1); |
120 | #endif | |
121 | } | |
122 | ||
2c42f1e8 IJ |
123 | |
124 | static bool os_parse_runas_uid_gid(const char *optarg) | |
125 | { | |
126 | unsigned long lv; | |
127 | const char *ep; | |
128 | uid_t got_uid; | |
129 | gid_t got_gid; | |
130 | int rc; | |
131 | ||
132 | rc = qemu_strtoul(optarg, &ep, 0, &lv); | |
133 | got_uid = lv; /* overflow here is ID in C99 */ | |
134 | if (rc || *ep != ':' || got_uid != lv || got_uid == (uid_t)-1) { | |
135 | return false; | |
136 | } | |
137 | ||
138 | rc = qemu_strtoul(ep + 1, 0, 0, &lv); | |
139 | got_gid = lv; /* overflow here is ID in C99 */ | |
140 | if (rc || got_gid != lv || got_gid == (gid_t)-1) { | |
141 | return false; | |
142 | } | |
143 | ||
144 | user_pwd = NULL; | |
145 | user_uid = got_uid; | |
146 | user_gid = got_gid; | |
147 | return true; | |
148 | } | |
149 | ||
59a5264b JS |
150 | /* |
151 | * Parse OS specific command line options. | |
152 | * return 0 if option handled, -1 otherwise | |
153 | */ | |
1217d6ca | 154 | int os_parse_cmd_args(int index, const char *optarg) |
59a5264b JS |
155 | { |
156 | switch (index) { | |
8847cfe8 JS |
157 | case QEMU_OPTION_runas: |
158 | user_pwd = getpwnam(optarg); | |
2c42f1e8 IJ |
159 | if (user_pwd) { |
160 | user_uid = -1; | |
161 | user_gid = -1; | |
162 | } else if (!os_parse_runas_uid_gid(optarg)) { | |
163 | error_report("User \"%s\" doesn't exist" | |
164 | " (and is not <uid>:<gid>)", | |
165 | optarg); | |
8847cfe8 JS |
166 | exit(1); |
167 | } | |
168 | break; | |
0766379d JS |
169 | case QEMU_OPTION_chroot: |
170 | chroot_dir = optarg; | |
171 | break; | |
eb505be1 JS |
172 | case QEMU_OPTION_daemonize: |
173 | daemonize = 1; | |
174 | break; | |
70678b82 AL |
175 | #if defined(CONFIG_LINUX) |
176 | case QEMU_OPTION_enablefips: | |
177 | fips_set_state(true); | |
178 | break; | |
179 | #endif | |
1217d6ca TH |
180 | default: |
181 | return -1; | |
59a5264b | 182 | } |
1217d6ca TH |
183 | |
184 | return 0; | |
59a5264b | 185 | } |
8847cfe8 | 186 | |
e06eb601 | 187 | static void change_process_uid(void) |
8847cfe8 | 188 | { |
2c42f1e8 IJ |
189 | assert((user_uid == (uid_t)-1) || user_pwd == NULL); |
190 | assert((user_uid == (uid_t)-1) == | |
191 | (user_gid == (gid_t)-1)); | |
192 | ||
193 | if (user_pwd || user_uid != (uid_t)-1) { | |
194 | gid_t intended_gid = user_pwd ? user_pwd->pw_gid : user_gid; | |
195 | uid_t intended_uid = user_pwd ? user_pwd->pw_uid : user_uid; | |
196 | if (setgid(intended_gid) < 0) { | |
197 | error_report("Failed to setgid(%d)", intended_gid); | |
8847cfe8 JS |
198 | exit(1); |
199 | } | |
2c42f1e8 IJ |
200 | if (user_pwd) { |
201 | if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { | |
202 | error_report("Failed to initgroups(\"%s\", %d)", | |
203 | user_pwd->pw_name, user_pwd->pw_gid); | |
204 | exit(1); | |
205 | } | |
206 | } else { | |
207 | if (setgroups(1, &user_gid) < 0) { | |
208 | error_report("Failed to setgroups(1, [%d])", | |
209 | user_gid); | |
210 | exit(1); | |
211 | } | |
cc4662f9 | 212 | } |
2c42f1e8 IJ |
213 | if (setuid(intended_uid) < 0) { |
214 | error_report("Failed to setuid(%d)", intended_uid); | |
8847cfe8 JS |
215 | exit(1); |
216 | } | |
217 | if (setuid(0) != -1) { | |
f0a2171b | 218 | error_report("Dropping privileges failed"); |
8847cfe8 JS |
219 | exit(1); |
220 | } | |
221 | } | |
222 | } | |
0766379d | 223 | |
e06eb601 | 224 | static void change_root(void) |
0766379d JS |
225 | { |
226 | if (chroot_dir) { | |
227 | if (chroot(chroot_dir) < 0) { | |
22cd4f48 | 228 | error_report("chroot failed"); |
0766379d JS |
229 | exit(1); |
230 | } | |
231 | if (chdir("/")) { | |
a7aaec14 | 232 | error_report("not able to chdir to /: %s", strerror(errno)); |
0766379d JS |
233 | exit(1); |
234 | } | |
235 | } | |
236 | ||
237 | } | |
eb505be1 JS |
238 | |
239 | void os_daemonize(void) | |
240 | { | |
241 | if (daemonize) { | |
63ce8e15 | 242 | pid_t pid; |
0be5e436 | 243 | int fds[2]; |
eb505be1 | 244 | |
63ce8e15 GA |
245 | if (pipe(fds) == -1) { |
246 | exit(1); | |
247 | } | |
eb505be1 | 248 | |
63ce8e15 GA |
249 | pid = fork(); |
250 | if (pid > 0) { | |
251 | uint8_t status; | |
252 | ssize_t len; | |
eb505be1 | 253 | |
63ce8e15 | 254 | close(fds[1]); |
eb505be1 | 255 | |
ccea25f1 MT |
256 | do { |
257 | len = read(fds[0], &status, 1); | |
258 | } while (len < 0 && errno == EINTR); | |
fee78fd6 MT |
259 | |
260 | /* only exit successfully if our child actually wrote | |
261 | * a one-byte zero to our pipe, upon successful init */ | |
262 | exit(len == 1 && status == 0 ? 0 : 1); | |
263 | ||
264 | } else if (pid < 0) { | |
265 | exit(1); | |
266 | } | |
eb505be1 | 267 | |
63ce8e15 | 268 | close(fds[0]); |
0be5e436 MT |
269 | daemon_pipe = fds[1]; |
270 | qemu_set_cloexec(daemon_pipe); | |
eb505be1 | 271 | |
63ce8e15 | 272 | setsid(); |
eb505be1 | 273 | |
63ce8e15 GA |
274 | pid = fork(); |
275 | if (pid > 0) { | |
276 | exit(0); | |
277 | } else if (pid < 0) { | |
278 | exit(1); | |
279 | } | |
280 | umask(027); | |
eb505be1 JS |
281 | |
282 | signal(SIGTSTP, SIG_IGN); | |
283 | signal(SIGTTOU, SIG_IGN); | |
284 | signal(SIGTTIN, SIG_IGN); | |
285 | } | |
286 | } | |
287 | ||
288 | void os_setup_post(void) | |
289 | { | |
290 | int fd = 0; | |
291 | ||
292 | if (daemonize) { | |
eb505be1 | 293 | if (chdir("/")) { |
a7aaec14 | 294 | error_report("not able to chdir to /: %s", strerror(errno)); |
eb505be1 JS |
295 | exit(1); |
296 | } | |
63ce8e15 GA |
297 | TFR(fd = qemu_open("/dev/null", O_RDWR)); |
298 | if (fd == -1) { | |
299 | exit(1); | |
300 | } | |
eb505be1 JS |
301 | } |
302 | ||
e06eb601 JS |
303 | change_root(); |
304 | change_process_uid(); | |
eb505be1 JS |
305 | |
306 | if (daemonize) { | |
25cec2b8 MT |
307 | uint8_t status = 0; |
308 | ssize_t len; | |
309 | ||
eb505be1 JS |
310 | dup2(fd, 0); |
311 | dup2(fd, 1); | |
96c33a45 DA |
312 | /* In case -D is given do not redirect stderr to /dev/null */ |
313 | if (!qemu_logfile) { | |
314 | dup2(fd, 2); | |
315 | } | |
eb505be1 JS |
316 | |
317 | close(fd); | |
25cec2b8 MT |
318 | |
319 | do { | |
320 | len = write(daemon_pipe, &status, 1); | |
321 | } while (len < 0 && errno == EINTR); | |
322 | if (len != 1) { | |
323 | exit(1); | |
324 | } | |
eb505be1 JS |
325 | } |
326 | } | |
327 | ||
9156d763 JS |
328 | void os_set_line_buffering(void) |
329 | { | |
330 | setvbuf(stdout, NULL, _IOLBF, 0); | |
331 | } | |
949d31e6 | 332 | |
995ee2bf HM |
333 | bool is_daemonized(void) |
334 | { | |
335 | return daemonize; | |
336 | } | |
888a6bc6 SM |
337 | |
338 | int os_mlock(void) | |
339 | { | |
340 | int ret = 0; | |
341 | ||
342 | ret = mlockall(MCL_CURRENT | MCL_FUTURE); | |
343 | if (ret < 0) { | |
a7aaec14 | 344 | error_report("mlockall: %s", strerror(errno)); |
888a6bc6 SM |
345 | } |
346 | ||
347 | return ret; | |
348 | } |