target/riscv: vmfirst find-first-set mask bit
[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 #include <pwd.h>
29 #include <grp.h>
30 #include <libgen.h>
31
32 #include "qemu-common.h"
33 /* Needed early for CONFIG_BSD etc. */
34 #include "net/slirp.h"
35 #include "qemu-options.h"
36 #include "qemu/error-report.h"
37 #include "qemu/log.h"
38 #include "sysemu/runstate.h"
39 #include "qemu/cutils.h"
40
41 #ifdef CONFIG_LINUX
42 #include <sys/prctl.h>
43 #endif
44
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
53 static const char *chroot_dir;
54 static int daemonize;
55 static int daemon_pipe;
56
57 void os_setup_early_signal_handling(void)
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 }
65
66 static void termsig_handler(int signal, siginfo_t *info, void *c)
67 {
68 qemu_system_killed(info->si_signo, info->si_pid);
69 }
70
71 void os_setup_signal_handling(void)
72 {
73 struct sigaction act;
74
75 memset(&act, 0, sizeof(act));
76 act.sa_sigaction = termsig_handler;
77 act.sa_flags = SA_SIGINFO;
78 sigaction(SIGINT, &act, NULL);
79 sigaction(SIGHUP, &act, NULL);
80 sigaction(SIGTERM, &act, NULL);
81 }
82
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 */
88 char *os_find_datadir(void)
89 {
90 g_autofree char *exec_dir = NULL;
91 g_autofree char *dir = NULL;
92
93 exec_dir = qemu_get_exec_dir();
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);
99 }
100
101 return g_strdup(CONFIG_QEMU_DATADIR);
102 }
103
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;
110 pstrcpy(name, sizeof(name), s);
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)) {
114 error_report("unable to change process name: %s", strerror(errno));
115 exit(1);
116 }
117 #else
118 error_report("Change of process name not supported by your OS");
119 exit(1);
120 #endif
121 }
122
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
150 /*
151 * Parse OS specific command line options.
152 * return 0 if option handled, -1 otherwise
153 */
154 int os_parse_cmd_args(int index, const char *optarg)
155 {
156 switch (index) {
157 case QEMU_OPTION_runas:
158 user_pwd = getpwnam(optarg);
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);
166 exit(1);
167 }
168 break;
169 case QEMU_OPTION_chroot:
170 chroot_dir = optarg;
171 break;
172 case QEMU_OPTION_daemonize:
173 daemonize = 1;
174 break;
175 #if defined(CONFIG_LINUX)
176 case QEMU_OPTION_enablefips:
177 fips_set_state(true);
178 break;
179 #endif
180 default:
181 return -1;
182 }
183
184 return 0;
185 }
186
187 static void change_process_uid(void)
188 {
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);
198 exit(1);
199 }
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 }
212 }
213 if (setuid(intended_uid) < 0) {
214 error_report("Failed to setuid(%d)", intended_uid);
215 exit(1);
216 }
217 if (setuid(0) != -1) {
218 error_report("Dropping privileges failed");
219 exit(1);
220 }
221 }
222 }
223
224 static void change_root(void)
225 {
226 if (chroot_dir) {
227 if (chroot(chroot_dir) < 0) {
228 error_report("chroot failed");
229 exit(1);
230 }
231 if (chdir("/")) {
232 error_report("not able to chdir to /: %s", strerror(errno));
233 exit(1);
234 }
235 }
236
237 }
238
239 void os_daemonize(void)
240 {
241 if (daemonize) {
242 pid_t pid;
243 int fds[2];
244
245 if (pipe(fds) == -1) {
246 exit(1);
247 }
248
249 pid = fork();
250 if (pid > 0) {
251 uint8_t status;
252 ssize_t len;
253
254 close(fds[1]);
255
256 do {
257 len = read(fds[0], &status, 1);
258 } while (len < 0 && errno == EINTR);
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 }
267
268 close(fds[0]);
269 daemon_pipe = fds[1];
270 qemu_set_cloexec(daemon_pipe);
271
272 setsid();
273
274 pid = fork();
275 if (pid > 0) {
276 exit(0);
277 } else if (pid < 0) {
278 exit(1);
279 }
280 umask(027);
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) {
293 if (chdir("/")) {
294 error_report("not able to chdir to /: %s", strerror(errno));
295 exit(1);
296 }
297 TFR(fd = qemu_open("/dev/null", O_RDWR));
298 if (fd == -1) {
299 exit(1);
300 }
301 }
302
303 change_root();
304 change_process_uid();
305
306 if (daemonize) {
307 uint8_t status = 0;
308 ssize_t len;
309
310 dup2(fd, 0);
311 dup2(fd, 1);
312 /* In case -D is given do not redirect stderr to /dev/null */
313 if (!qemu_logfile) {
314 dup2(fd, 2);
315 }
316
317 close(fd);
318
319 do {
320 len = write(daemon_pipe, &status, 1);
321 } while (len < 0 && errno == EINTR);
322 if (len != 1) {
323 exit(1);
324 }
325 }
326 }
327
328 void os_set_line_buffering(void)
329 {
330 setvbuf(stdout, NULL, _IOLBF, 0);
331 }
332
333 bool is_daemonized(void)
334 {
335 return daemonize;
336 }
337
338 int os_mlock(void)
339 {
340 int ret = 0;
341
342 ret = mlockall(MCL_CURRENT | MCL_FUTURE);
343 if (ret < 0) {
344 error_report("mlockall: %s", strerror(errno));
345 }
346
347 return ret;
348 }