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 <grp.h> 35 #include <libgen.h> 36 37 /* Needed early for CONFIG_BSD etc. */ 38 #include "config-host.h" 39 #include "sysemu/sysemu.h" 40 #include "net/slirp.h" 41 #include "qemu-options.h" 42 43 #ifdef CONFIG_LINUX 44 #include <sys/prctl.h> 45 #endif 46 47 #ifdef __FreeBSD__ 48 #include <sys/sysctl.h> 49 #endif 50 51 static struct passwd *user_pwd; 52 static const char *chroot_dir; 53 static int daemonize; 54 static int fds[2]; 55 56 void 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 65 static void termsig_handler(int signal, siginfo_t *info, void *c) 66 { 67 qemu_system_killed(info->si_signo, info->si_pid); 68 } 69 70 void 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 /* Find a likely location for support files using the location of the binary. 83 For installed binaries this will be "$bindir/../share/qemu". When 84 running from the build tree this will be "$bindir/../pc-bios". */ 85 #define SHARE_SUFFIX "/share/qemu" 86 #define BUILD_SUFFIX "/pc-bios" 87 char *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 = 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(exec_dir); 112 return res; 113 } 114 #undef SHARE_SUFFIX 115 #undef BUILD_SUFFIX 116 117 void os_set_proc_name(const char *s) 118 { 119 #if defined(PR_SET_NAME) 120 char name[16]; 121 if (!s) 122 return; 123 pstrcpy(name, sizeof(name), s); 124 /* Could rewrite argv[0] too, but that's a bit more complicated. 125 This simple way is enough for `top'. */ 126 if (prctl(PR_SET_NAME, name)) { 127 perror("unable to change process name"); 128 exit(1); 129 } 130 #else 131 fprintf(stderr, "Change of process name not supported by your OS\n"); 132 exit(1); 133 #endif 134 } 135 136 /* 137 * Parse OS specific command line options. 138 * return 0 if option handled, -1 otherwise 139 */ 140 void os_parse_cmd_args(int index, const char *optarg) 141 { 142 switch (index) { 143 #ifdef CONFIG_SLIRP 144 case QEMU_OPTION_smb: 145 if (net_slirp_smb(optarg) < 0) 146 exit(1); 147 break; 148 #endif 149 case QEMU_OPTION_runas: 150 user_pwd = getpwnam(optarg); 151 if (!user_pwd) { 152 fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); 153 exit(1); 154 } 155 break; 156 case QEMU_OPTION_chroot: 157 chroot_dir = optarg; 158 break; 159 case QEMU_OPTION_daemonize: 160 daemonize = 1; 161 break; 162 #if defined(CONFIG_LINUX) 163 case QEMU_OPTION_enablefips: 164 fips_set_state(true); 165 break; 166 #endif 167 } 168 } 169 170 static void change_process_uid(void) 171 { 172 if (user_pwd) { 173 if (setgid(user_pwd->pw_gid) < 0) { 174 fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); 175 exit(1); 176 } 177 if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { 178 fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n", 179 user_pwd->pw_name, user_pwd->pw_gid); 180 exit(1); 181 } 182 if (setuid(user_pwd->pw_uid) < 0) { 183 fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); 184 exit(1); 185 } 186 if (setuid(0) != -1) { 187 fprintf(stderr, "Dropping privileges failed\n"); 188 exit(1); 189 } 190 } 191 } 192 193 static void change_root(void) 194 { 195 if (chroot_dir) { 196 if (chroot(chroot_dir) < 0) { 197 fprintf(stderr, "chroot failed\n"); 198 exit(1); 199 } 200 if (chdir("/")) { 201 perror("not able to chdir to /"); 202 exit(1); 203 } 204 } 205 206 } 207 208 void os_daemonize(void) 209 { 210 if (daemonize) { 211 pid_t pid; 212 213 if (pipe(fds) == -1) 214 exit(1); 215 216 pid = fork(); 217 if (pid > 0) { 218 uint8_t status; 219 ssize_t len; 220 221 close(fds[1]); 222 223 again: 224 len = read(fds[0], &status, 1); 225 if (len == -1 && (errno == EINTR)) 226 goto again; 227 228 if (len != 1) 229 exit(1); 230 else if (status == 1) { 231 fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno)); 232 exit(1); 233 } else 234 exit(0); 235 } else if (pid < 0) 236 exit(1); 237 238 close(fds[0]); 239 qemu_set_cloexec(fds[1]); 240 241 setsid(); 242 243 pid = fork(); 244 if (pid > 0) 245 exit(0); 246 else if (pid < 0) 247 exit(1); 248 249 umask(027); 250 251 signal(SIGTSTP, SIG_IGN); 252 signal(SIGTTOU, SIG_IGN); 253 signal(SIGTTIN, SIG_IGN); 254 } 255 } 256 257 void os_setup_post(void) 258 { 259 int fd = 0; 260 261 if (daemonize) { 262 uint8_t status = 0; 263 ssize_t len; 264 265 again1: 266 len = write(fds[1], &status, 1); 267 if (len == -1 && (errno == EINTR)) 268 goto again1; 269 270 if (len != 1) 271 exit(1); 272 273 if (chdir("/")) { 274 perror("not able to chdir to /"); 275 exit(1); 276 } 277 TFR(fd = qemu_open("/dev/null", O_RDWR)); 278 if (fd == -1) 279 exit(1); 280 } 281 282 change_root(); 283 change_process_uid(); 284 285 if (daemonize) { 286 dup2(fd, 0); 287 dup2(fd, 1); 288 dup2(fd, 2); 289 290 close(fd); 291 } 292 } 293 294 void os_pidfile_error(void) 295 { 296 if (daemonize) { 297 uint8_t status = 1; 298 if (write(fds[1], &status, 1) != 1) { 299 perror("daemonize. Writing to pipe\n"); 300 } 301 } else 302 fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno)); 303 } 304 305 void os_set_line_buffering(void) 306 { 307 setvbuf(stdout, NULL, _IOLBF, 0); 308 } 309 310 int qemu_create_pidfile(const char *filename) 311 { 312 char buffer[128]; 313 int len; 314 int fd; 315 316 fd = qemu_open(filename, O_RDWR | O_CREAT, 0600); 317 if (fd == -1) { 318 return -1; 319 } 320 if (lockf(fd, F_TLOCK, 0) == -1) { 321 close(fd); 322 return -1; 323 } 324 len = snprintf(buffer, sizeof(buffer), FMT_pid "\n", getpid()); 325 if (write(fd, buffer, len) != len) { 326 close(fd); 327 return -1; 328 } 329 330 /* keep pidfile open & locked forever */ 331 return 0; 332 } 333 334 bool is_daemonized(void) 335 { 336 return daemonize; 337 } 338 339 int os_mlock(void) 340 { 341 int ret = 0; 342 343 ret = mlockall(MCL_CURRENT | MCL_FUTURE); 344 if (ret < 0) { 345 perror("mlockall"); 346 } 347 348 return ret; 349 } 350