David 'Digit' Turner | 088edf8 | 2011-05-09 15:59:28 +0200 | [diff] [blame] | 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 <libgen.h> |
| 35 | |
| 36 | /* Needed early for CONFIG_BSD etc. */ |
| 37 | #include "config-host.h" |
David 'Digit' Turner | 34c48ff | 2013-12-15 00:25:03 +0100 | [diff] [blame] | 38 | #include "sysemu/sysemu.h" |
David 'Digit' Turner | cc330d4 | 2013-12-14 23:26:42 +0100 | [diff] [blame] | 39 | #include "net/net.h" |
David 'Digit' Turner | 088edf8 | 2011-05-09 15:59:28 +0200 | [diff] [blame] | 40 | #include "qemu-options.h" |
| 41 | |
| 42 | #ifdef CONFIG_LINUX |
| 43 | #include <sys/prctl.h> |
| 44 | #include <sys/syscall.h> |
| 45 | #endif |
| 46 | |
| 47 | #ifdef CONFIG_EVENTFD |
| 48 | #include <sys/eventfd.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) |
| 66 | { |
| 67 | qemu_system_shutdown_request(); |
| 68 | } |
| 69 | |
| 70 | static void sigchld_handler(int signal) |
| 71 | { |
| 72 | waitpid(-1, NULL, WNOHANG); |
| 73 | } |
| 74 | |
| 75 | void os_setup_signal_handling(void) |
| 76 | { |
| 77 | struct sigaction act; |
| 78 | |
| 79 | memset(&act, 0, sizeof(act)); |
| 80 | act.sa_handler = termsig_handler; |
| 81 | sigaction(SIGINT, &act, NULL); |
| 82 | sigaction(SIGHUP, &act, NULL); |
| 83 | sigaction(SIGTERM, &act, NULL); |
| 84 | |
| 85 | act.sa_handler = sigchld_handler; |
| 86 | act.sa_flags = SA_NOCLDSTOP; |
| 87 | sigaction(SIGCHLD, &act, NULL); |
| 88 | } |
| 89 | |
| 90 | /* Find a likely location for support files using the location of the binary. |
| 91 | For installed binaries this will be "$bindir/../share/qemu". When |
| 92 | running from the build tree this will be "$bindir/../pc-bios". */ |
| 93 | #define SHARE_SUFFIX "/share/qemu" |
| 94 | #define BUILD_SUFFIX "/pc-bios" |
| 95 | char *os_find_datadir(const char *argv0) |
| 96 | { |
| 97 | char *dir; |
| 98 | char *p = NULL; |
| 99 | char *res; |
| 100 | char buf[PATH_MAX]; |
| 101 | size_t max_len; |
| 102 | |
| 103 | #if defined(__linux__) |
| 104 | { |
| 105 | int len; |
| 106 | len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); |
| 107 | if (len > 0) { |
| 108 | buf[len] = 0; |
| 109 | p = buf; |
| 110 | } |
| 111 | } |
| 112 | #elif defined(__FreeBSD__) |
| 113 | { |
| 114 | static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; |
| 115 | size_t len = sizeof(buf) - 1; |
| 116 | |
| 117 | *buf = '\0'; |
| 118 | if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && |
| 119 | *buf) { |
| 120 | buf[sizeof(buf) - 1] = '\0'; |
| 121 | p = buf; |
| 122 | } |
| 123 | } |
| 124 | #endif |
| 125 | /* If we don't have any way of figuring out the actual executable |
| 126 | location then try argv[0]. */ |
| 127 | if (!p) { |
| 128 | p = realpath(argv0, buf); |
| 129 | if (!p) { |
| 130 | return NULL; |
| 131 | } |
| 132 | } |
| 133 | dir = dirname(p); |
| 134 | dir = dirname(dir); |
| 135 | |
| 136 | max_len = strlen(dir) + |
| 137 | MAX(strlen(SHARE_SUFFIX), strlen(BUILD_SUFFIX)) + 1; |
David 'Digit' Turner | aa8236d | 2014-01-10 17:02:29 +0100 | [diff] [blame] | 138 | res = g_malloc0(max_len); |
David 'Digit' Turner | 088edf8 | 2011-05-09 15:59:28 +0200 | [diff] [blame] | 139 | snprintf(res, max_len, "%s%s", dir, SHARE_SUFFIX); |
| 140 | if (access(res, R_OK)) { |
| 141 | snprintf(res, max_len, "%s%s", dir, BUILD_SUFFIX); |
| 142 | if (access(res, R_OK)) { |
David 'Digit' Turner | aa8236d | 2014-01-10 17:02:29 +0100 | [diff] [blame] | 143 | g_free(res); |
David 'Digit' Turner | 088edf8 | 2011-05-09 15:59:28 +0200 | [diff] [blame] | 144 | res = NULL; |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | return res; |
| 149 | } |
| 150 | #undef SHARE_SUFFIX |
| 151 | #undef BUILD_SUFFIX |
| 152 | |
| 153 | void os_set_proc_name(const char *s) |
| 154 | { |
| 155 | #if defined(PR_SET_NAME) |
| 156 | char name[16]; |
| 157 | if (!s) |
| 158 | return; |
| 159 | name[sizeof(name) - 1] = 0; |
| 160 | strncpy(name, s, sizeof(name)); |
| 161 | /* Could rewrite argv[0] too, but that's a bit more complicated. |
| 162 | This simple way is enough for `top'. */ |
| 163 | if (prctl(PR_SET_NAME, name)) { |
| 164 | perror("unable to change process name"); |
| 165 | exit(1); |
| 166 | } |
| 167 | #else |
| 168 | fprintf(stderr, "Change of process name not supported by your OS\n"); |
| 169 | exit(1); |
| 170 | #endif |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Parse OS specific command line options. |
| 175 | * return 0 if option handled, -1 otherwise |
| 176 | */ |
| 177 | void os_parse_cmd_args(int index, const char *optarg) |
| 178 | { |
| 179 | switch (index) { |
| 180 | #ifdef CONFIG_SLIRP |
| 181 | case QEMU_OPTION_smb: |
| 182 | #if 1 |
| 183 | net_slirp_smb(optarg); |
| 184 | #else |
| 185 | if (net_slirp_smb(optarg) < 0) |
| 186 | exit(1); |
| 187 | #endif |
| 188 | break; |
| 189 | #endif |
| 190 | case QEMU_OPTION_runas: |
| 191 | user_pwd = getpwnam(optarg); |
| 192 | if (!user_pwd) { |
| 193 | fprintf(stderr, "User \"%s\" doesn't exist\n", optarg); |
| 194 | exit(1); |
| 195 | } |
| 196 | break; |
| 197 | case QEMU_OPTION_chroot: |
| 198 | chroot_dir = optarg; |
| 199 | break; |
| 200 | case QEMU_OPTION_daemonize: |
| 201 | daemonize = 1; |
| 202 | break; |
| 203 | } |
| 204 | return; |
| 205 | } |
| 206 | |
| 207 | static void change_process_uid(void) |
| 208 | { |
| 209 | if (user_pwd) { |
| 210 | if (setgid(user_pwd->pw_gid) < 0) { |
| 211 | fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); |
| 212 | exit(1); |
| 213 | } |
| 214 | if (setuid(user_pwd->pw_uid) < 0) { |
| 215 | fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); |
| 216 | exit(1); |
| 217 | } |
| 218 | if (setuid(0) != -1) { |
| 219 | fprintf(stderr, "Dropping privileges failed\n"); |
| 220 | exit(1); |
| 221 | } |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | static void change_root(void) |
| 226 | { |
| 227 | if (chroot_dir) { |
| 228 | if (chroot(chroot_dir) < 0) { |
| 229 | fprintf(stderr, "chroot failed\n"); |
| 230 | exit(1); |
| 231 | } |
| 232 | if (chdir("/")) { |
| 233 | perror("not able to chdir to /"); |
| 234 | exit(1); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | } |
| 239 | |
| 240 | void os_daemonize(void) |
| 241 | { |
| 242 | if (daemonize) { |
| 243 | pid_t pid; |
| 244 | |
| 245 | if (pipe(fds) == -1) |
| 246 | exit(1); |
| 247 | |
| 248 | pid = fork(); |
| 249 | if (pid > 0) { |
| 250 | uint8_t status; |
| 251 | ssize_t len; |
| 252 | |
| 253 | close(fds[1]); |
| 254 | |
| 255 | again: |
| 256 | len = read(fds[0], &status, 1); |
| 257 | if (len == -1 && (errno == EINTR)) |
| 258 | goto again; |
| 259 | |
| 260 | if (len != 1) |
| 261 | exit(1); |
| 262 | else if (status == 1) { |
| 263 | fprintf(stderr, "Could not acquire pidfile: %s\n", strerror(errno)); |
| 264 | exit(1); |
| 265 | } else |
| 266 | exit(0); |
| 267 | } else if (pid < 0) |
| 268 | exit(1); |
| 269 | |
| 270 | close(fds[0]); |
| 271 | qemu_set_cloexec(fds[1]); |
| 272 | |
| 273 | setsid(); |
| 274 | |
| 275 | pid = fork(); |
| 276 | if (pid > 0) |
| 277 | exit(0); |
| 278 | else if (pid < 0) |
| 279 | exit(1); |
| 280 | |
| 281 | umask(027); |
| 282 | |
| 283 | signal(SIGTSTP, SIG_IGN); |
| 284 | signal(SIGTTOU, SIG_IGN); |
| 285 | signal(SIGTTIN, SIG_IGN); |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | void os_setup_post(void) |
| 290 | { |
| 291 | int fd = 0; |
| 292 | |
| 293 | if (daemonize) { |
| 294 | uint8_t status = 0; |
| 295 | ssize_t len; |
| 296 | |
| 297 | again1: |
| 298 | len = write(fds[1], &status, 1); |
| 299 | if (len == -1 && (errno == EINTR)) |
| 300 | goto again1; |
| 301 | |
| 302 | if (len != 1) |
| 303 | exit(1); |
| 304 | |
| 305 | if (chdir("/")) { |
| 306 | perror("not able to chdir to /"); |
| 307 | exit(1); |
| 308 | } |
| 309 | TFR(fd = qemu_open("/dev/null", O_RDWR)); |
| 310 | if (fd == -1) |
| 311 | exit(1); |
| 312 | } |
| 313 | |
| 314 | change_root(); |
| 315 | change_process_uid(); |
| 316 | |
| 317 | if (daemonize) { |
| 318 | dup2(fd, 0); |
| 319 | dup2(fd, 1); |
| 320 | dup2(fd, 2); |
| 321 | |
| 322 | close(fd); |
| 323 | } |
| 324 | } |
| 325 | |
| 326 | void os_pidfile_error(void) |
| 327 | { |
| 328 | if (daemonize) { |
| 329 | uint8_t status = 1; |
| 330 | if (write(fds[1], &status, 1) != 1) { |
| 331 | perror("daemonize. Writing to pipe\n"); |
| 332 | } |
| 333 | } else |
| 334 | fprintf(stderr, "Could not acquire pid file: %s\n", strerror(errno)); |
| 335 | } |
| 336 | |
| 337 | void os_set_line_buffering(void) |
| 338 | { |
| 339 | setvbuf(stdout, NULL, _IOLBF, 0); |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * Creates an eventfd that looks like a pipe and has EFD_CLOEXEC set. |
| 344 | */ |
| 345 | int qemu_eventfd(int fds[2]) |
| 346 | { |
| 347 | #ifdef CONFIG_EVENTFD |
| 348 | int ret; |
| 349 | |
| 350 | ret = eventfd(0, 0); |
| 351 | if (ret >= 0) { |
| 352 | fds[0] = ret; |
| 353 | qemu_set_cloexec(ret); |
| 354 | if ((fds[1] = dup(ret)) == -1) { |
| 355 | close(ret); |
| 356 | return -1; |
| 357 | } |
| 358 | qemu_set_cloexec(fds[1]); |
| 359 | return 0; |
| 360 | } |
| 361 | |
| 362 | if (errno != ENOSYS) { |
| 363 | return -1; |
| 364 | } |
| 365 | #endif |
| 366 | |
| 367 | return qemu_pipe(fds); |
| 368 | } |
| 369 | |
| 370 | int qemu_create_pidfile(const char *filename) |
| 371 | { |
| 372 | char buffer[128]; |
| 373 | int len; |
| 374 | int fd; |
| 375 | |
| 376 | fd = qemu_open(filename, O_RDWR | O_CREAT, 0600); |
| 377 | if (fd == -1) { |
| 378 | return -1; |
| 379 | } |
| 380 | if (lockf(fd, F_TLOCK, 0) == -1) { |
| 381 | return -1; |
| 382 | } |
| 383 | len = snprintf(buffer, sizeof(buffer), "%ld\n", (long)getpid()); |
| 384 | if (write(fd, buffer, len) != len) { |
| 385 | return -1; |
| 386 | } |
| 387 | |
| 388 | return 0; |
| 389 | } |