main.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <dbus/dbus.h>
  23
  24 #include <stdio.h>
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <getopt.h>
  31 #include <signal.h>
  32 #include <sys/wait.h>
  33 #include <fcntl.h>
  34
  35 #include "manager.h"
  36 #include "log.h"
  37 #include "mount-setup.h"
  38 #include "hostname-setup.h"
  39 #include "load-fragment.h"
  40
  41 static enum {
  42         ACTION_RUN,
  43         ACTION_HELP,
  44         ACTION_TEST,
  45         ACTION_DUMP_CONFIGURATION_ITEMS
  46 } action = ACTION_RUN;
  47
  48 static char *default_unit = NULL;
  49 static ManagerRunningAs running_as = _MANAGER_RUNNING_AS_INVALID;
  50
  51 static bool dump_core = true;
  52 static bool crash_shell = false;
  53 static int crash_chvt = -1;
  54
  55 static bool confirm_spawn = false;
  56
  57 _noreturn static void freeze(void) {
  58         for (;;)
  59                 pause();
  60 }
  61
  62 _noreturn static void crash(int sig) {
  63
  64         if (!dump_core)
  65                 log_error("Caught <%s>, not dumping core.", strsignal(sig));
  66         else {
  67                 pid_t pid;
  68
  69                 if ((pid = fork()) < 0)
  70                         log_error("Caught <%s>, cannot fork for core dump: %s", strsignal(sig), strerror(errno));
  71
  72                 else if (pid == 0) {
  73                         struct sigaction sa;
  74                         struct rlimit rl;
  75
  76                         /* Enable default signal handler for core dump */
  77                         zero(sa);
  78                         sa.sa_handler = SIG_DFL;
  79                         assert_se(sigaction(sig, &sa, NULL) == 0);
  80
  81                         /* Don't limit the core dump size */
  82                         zero(rl);
  83                         rl.rlim_cur = RLIM_INFINITY;
  84                         rl.rlim_max = RLIM_INFINITY;
  85                         setrlimit(RLIMIT_CORE, &rl);
  86
  87                         /* Just to be sure... */
  88                         assert_se(chdir("/") == 0);
  89
  90                         /* Raise the signal again */
  91                         raise(sig);
  92
  93                         assert_not_reached("We shouldn't be here...");
  94                         _exit(1);
  95
  96                 } else {
  97                         int status, r;
  98
  99                         /* Order things nicely. */
 100                         if ((r = waitpid(pid, &status, 0)) < 0)
 101                                 log_error("Caught <%s>, waitpid() failed: %s", strsignal(sig), strerror(errno));
 102                         else if (!WCOREDUMP(status))
 103                                 log_error("Caught <%s>, core dump failed.", strsignal(sig));
 104                         else
 105                                 log_error("Caught <%s>, dumped core as pid %llu.", strsignal(sig), (unsigned long long) pid);
 106                 }
 107         }
 108
 109         if (crash_chvt)
 110                 chvt(crash_chvt);
 111
 112         if (crash_shell) {
 113                 log_info("Executing crash shell in 10s...");
 114                 sleep(10);
 115
 116                 execl("/bin/sh", "/bin/sh", NULL);
 117                 log_error("execl() failed: %s", strerror(errno));
 118         }
 119
 120         log_info("Freezing execution.");
 121         freeze();
 122 }
 123
 124 static void install_crash_handler(void) {
 125         struct sigaction sa;
 126
 127         zero(sa);
 128
 129         sa.sa_handler = crash;
 130         sa.sa_flags = SA_NODEFER;
 131
 132         assert_se(sigaction(SIGSEGV, &sa, NULL) == 0);
 133         assert_se(sigaction(SIGILL, &sa, NULL) == 0);
 134         assert_se(sigaction(SIGFPE, &sa, NULL) == 0);
 135         assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
 136         assert_se(sigaction(SIGQUIT, &sa, NULL) == 0);
 137         assert_se(sigaction(SIGABRT, &sa, NULL) == 0);
 138 }
 139
 140 static int console_setup(void) {
 141         int tty_fd = -1, null_fd = -1, r = 0;
 142
 143         /* If we are init, we connect stdout/stderr to /dev/console
 144          * and stdin to /dev/null and make sure we don't have a
 145          * controlling tty. */
 146
 147         release_terminal();
 148
 149         if ((tty_fd = open_terminal("/dev/console", O_WRONLY)) < 0) {
 150                 log_error("Failed to open /dev/console: %s", strerror(-tty_fd));
 151                 r = -tty_fd;
 152                 goto finish;
 153         }
 154
 155         if ((null_fd = open("/dev/null", O_RDONLY)) < 0) {
 156                 log_error("Failed to open /dev/null: %m");
 157                 r = -errno;
 158                 goto finish;
 159         }
 160
 161         assert(tty_fd >= 3);
 162         assert(null_fd >= 3);
 163
 164         if (reset_terminal(tty_fd) < 0)
 165                 log_error("Failed to reset /dev/console: %m");
 166
 167         if (dup2(tty_fd, STDOUT_FILENO) < 0 ||
 168             dup2(tty_fd, STDERR_FILENO) < 0 ||
 169             dup2(null_fd, STDIN_FILENO) < 0) {
 170                 log_error("Failed to dup2() device: %m");
 171                 r = -errno;
 172                 goto finish;
 173         }
 174
 175         r = 0;
 176
 177 finish:
 178         if (tty_fd >= 0)
 179                 close_nointr(tty_fd);
 180
 181         if (null_fd >= 0)
 182                 close_nointr(null_fd);
 183
 184         return r;
 185 }
 186
 187 static int set_default_unit(const char *u) {
 188         char *c;
 189
 190         assert(u);
 191
 192         if (!(c = strdup(u)))
 193                 return -ENOMEM;
 194
 195         free(default_unit);
 196         default_unit = c;
 197         return 0;
 198 }
 199
 200 static int parse_proc_cmdline_word(const char *word) {
 201
 202         static const char * const rlmap[] = {
 203                 "single", SPECIAL_RUNLEVEL1_TARGET,
 204                 "-s",     SPECIAL_RUNLEVEL1_TARGET,
 205                 "s",      SPECIAL_RUNLEVEL1_TARGET,
 206                 "S",      SPECIAL_RUNLEVEL1_TARGET,
 207                 "1",      SPECIAL_RUNLEVEL1_TARGET,
 208                 "2",      SPECIAL_RUNLEVEL2_TARGET,
 209                 "3",      SPECIAL_RUNLEVEL3_TARGET,
 210                 "4",      SPECIAL_RUNLEVEL4_TARGET,
 211                 "5",      SPECIAL_RUNLEVEL5_TARGET
 212         };
 213
 214         if (startswith(word, "systemd.default="))
 215                 return set_default_unit(word + 16);
 216
 217         else if (startswith(word, "systemd.log_target=")) {
 218
 219                 if (log_set_target_from_string(word + 19) < 0)
 220                         log_warning("Failed to parse log target %s. Ignoring.", word + 19);
 221
 222         } else if (startswith(word, "systemd.log_level=")) {
 223
 224                 if (log_set_max_level_from_string(word + 18) < 0)
 225                         log_warning("Failed to parse log level %s. Ignoring.", word + 18);
 226
 227         } else if (startswith(word, "systemd.dump_core=")) {
 228                 int r;
 229
 230                 if ((r = parse_boolean(word + 18)) < 0)
 231                         log_warning("Failed to parse dump core switch %s, Ignoring.", word + 18);
 232                 else
 233                         dump_core = r;
 234
 235         } else if (startswith(word, "systemd.crash_shell=")) {
 236                 int r;
 237
 238                 if ((r = parse_boolean(word + 20)) < 0)
 239                         log_warning("Failed to parse crash shell switch %s, Ignoring.", word + 20);
 240                 else
 241                         crash_shell = r;
 242
 243         } else if (startswith(word, "systemd.crash_chvt=")) {
 244                 int k;
 245
 246                 if (safe_atoi(word + 19, &k) < 0)
 247                         log_warning("Failed to parse crash chvt switch %s, Ignoring.", word + 19);
 248                 else
 249                         crash_chvt = k;
 250
 251         } else if (startswith(word, "systemd.")) {
 252
 253                 log_warning("Unknown kernel switch %s. Ignoring.", word);
 254
 255                 log_info("Supported kernel switches:");
 256                 log_info("systemd.default=UNIT                     Default unit to start");
 257                 log_info("systemd.log_target=console|kmsg|syslog   Log target");
 258                 log_info("systemd.log_level=LEVEL                  Log level");
 259                 log_info("systemd.dump_core=0|1                    Dump core on crash");
 260                 log_info("systemd.crash_shell=0|1                  On crash run shell");
 261                 log_info("systemd.crash_chvt=N                     Change to VT #N on crash");
 262
 263         } else {
 264                 unsigned i;
 265
 266                 /* SysV compatibility */
 267                 for (i = 0; i < ELEMENTSOF(rlmap); i += 2)
 268                         if (streq(word, rlmap[i]))
 269                                 return set_default_unit(rlmap[i+1]);
 270         }
 271
 272         return 0;
 273 }
 274
 275 static int parse_proc_cmdline(void) {
 276         char *line;
 277         int r;
 278         char *w;
 279         size_t l;
 280         char *state;
 281
 282         if ((r = read_one_line_file("/proc/cmdline", &line)) < 0) {
 283                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(errno));
 284                 return 0;
 285         }
 286
 287         FOREACH_WORD_QUOTED(w, l, line, state) {
 288                 char *word;
 289
 290                 if (!(word = strndup(w, l))) {
 291                         r = -ENOMEM;
 292                         goto finish;
 293                 }
 294
 295                 r = parse_proc_cmdline_word(word);
 296                 free(word);
 297
 298                 if (r < 0)
 299                         goto finish;
 300         }
 301
 302         r = 0;
 303
 304 finish:
 305         free(line);
 306         return r;
 307 }
 308
 309 static int parse_argv(int argc, char *argv[]) {
 310
 311         enum {
 312                 ARG_LOG_LEVEL = 0x100,
 313                 ARG_LOG_TARGET,
 314                 ARG_DEFAULT,
 315                 ARG_RUNNING_AS,
 316                 ARG_TEST,
 317                 ARG_DUMP_CONFIGURATION_ITEMS,
 318                 ARG_CONFIRM_SPAWN
 319         };
 320
 321         static const struct option options[] = {
 322                 { "log-level",  required_argument, NULL, ARG_LOG_LEVEL },
 323                 { "log-target", required_argument, NULL, ARG_LOG_TARGET },
 324                 { "default",    required_argument, NULL, ARG_DEFAULT },
 325                 { "running-as", required_argument, NULL, ARG_RUNNING_AS },
 326                 { "test",       no_argument,       NULL, ARG_TEST },
 327                 { "help",       no_argument,       NULL, 'h' },
 328                 { "dump-configuration-items", no_argument, NULL, ARG_DUMP_CONFIGURATION_ITEMS },
 329                 { "confirm-spawn", no_argument,    NULL, ARG_CONFIRM_SPAWN },
 330                 { NULL,         0,                 NULL, 0 }
 331         };
 332
 333         int c, r;
 334
 335         assert(argc >= 1);
 336         assert(argv);
 337
 338         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
 339
 340                 switch (c) {
 341
 342                 case ARG_LOG_LEVEL:
 343                         if ((r = log_set_max_level_from_string(optarg)) < 0) {
 344                                 log_error("Failed to parse log level %s.", optarg);
 345                                 return r;
 346                         }
 347
 348                         break;
 349
 350                 case ARG_LOG_TARGET:
 351
 352                         if ((r = log_set_target_from_string(optarg)) < 0) {
 353                                 log_error("Failed to parse log target %s.", optarg);
 354                                 return r;
 355                         }
 356
 357                         break;
 358
 359                 case ARG_DEFAULT:
 360
 361                         if ((r = set_default_unit(optarg)) < 0) {
 362                                 log_error("Failed to set default unit %s: %s", optarg, strerror(-r));
 363                                 return r;
 364                         }
 365
 366                         break;
 367
 368                 case ARG_RUNNING_AS: {
 369                         ManagerRunningAs as;
 370
 371                         if ((as = manager_running_as_from_string(optarg)) < 0) {
 372                                 log_error("Failed to parse running as value %s", optarg);
 373                                 return -EINVAL;
 374                         }
 375
 376                         running_as = as;
 377                         break;
 378                 }
 379
 380                 case ARG_TEST:
 381                         action = ACTION_TEST;
 382                         break;
 383
 384                 case ARG_DUMP_CONFIGURATION_ITEMS:
 385                         action = ACTION_DUMP_CONFIGURATION_ITEMS;
 386                         break;
 387
 388                 case ARG_CONFIRM_SPAWN:
 389                         confirm_spawn = true;
 390                         break;
 391
 392                 case 'h':
 393                         action = ACTION_HELP;
 394                         break;
 395
 396                 case '?':
 397                         return -EINVAL;
 398
 399                 default:
 400                         log_error("Unknown option code %c", c);
 401                         return -EINVAL;
 402                 }
 403
 404         return 0;
 405 }
 406
 407 static int help(void) {
 408
 409         printf("%s [options]\n\n"
 410                "  -h --help                      Show this help\n"
 411                "     --default=UNIT              Set default unit\n"
 412                "     --log-level=LEVEL           Set log level\n"
 413                "     --log-target=TARGET         Set log target (console, syslog, kmsg)\n"
 414                "     --running-as=AS             Set running as (init, system, session)\n"
 415                "     --test                      Determine startup sequence, dump it and exit\n"
 416                "     --dump-configuration-items  Dump understood unit configuration items\n"
 417                "     --confirm-spawn             Ask for confirmation when spawning processes\n",
 418                __progname);
 419
 420         return 0;
 421 }
 422
 423 int main(int argc, char *argv[]) {
 424         Manager *m = NULL;
 425         Unit *target = NULL;
 426         Job *job = NULL;
 427         int r, retval = 1;
 428
 429         if (getpid() == 1)
 430                 running_as = MANAGER_INIT;
 431         else if (getuid() == 0)
 432                 running_as = MANAGER_SYSTEM;
 433         else
 434                 running_as = MANAGER_SESSION;
 435
 436         if (set_default_unit(SPECIAL_DEFAULT_TARGET) < 0)
 437                 goto finish;
 438
 439         /* Mount /proc, /sys and friends, so that /proc/cmdline and
 440          * /proc/$PID/fd is available. */
 441         if (mount_setup() < 0)
 442                 goto finish;
 443
 444         /* Reset all signal handlers. */
 445         assert_se(reset_all_signal_handlers() == 0);
 446
 447         /* If we are init, we can block sigkill. Yay. */
 448         signal(SIGKILL, SIG_IGN);
 449         signal(SIGPIPE, SIG_IGN);
 450
 451         /* Close all open files */
 452         assert_se(close_all_fds(NULL, 0) == 0);
 453
 454         if (running_as != MANAGER_SESSION)
 455                 if (parse_proc_cmdline() < 0)
 456                         goto finish;
 457
 458         log_parse_environment();
 459
 460         if (parse_argv(argc, argv) < 0)
 461                 goto finish;
 462
 463         if (action == ACTION_HELP) {
 464                 retval = help();
 465                 goto finish;
 466         } else if (action == ACTION_DUMP_CONFIGURATION_ITEMS) {
 467                 unit_dump_config_items(stdout);
 468                 retval = 0;
 469                 goto finish;
 470         }
 471
 472         assert_se(action == ACTION_RUN || action == ACTION_TEST);
 473
 474         /* Set up PATH unless it is already set */
 475         setenv("PATH",
 476                "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
 477                running_as == MANAGER_INIT);
 478
 479         /* Move out of the way, so that we won't block unmounts */
 480         assert_se(chdir("/")  == 0);
 481
 482         if (running_as != MANAGER_SESSION) {
 483                 /* Become a session leader if we aren't one yet. */
 484                 setsid();
 485
 486                 /* Disable the umask logic */
 487                 umask(0);
 488         }
 489
 490         if (running_as == MANAGER_INIT)
 491                 console_setup();
 492
 493         /* Make sure D-Bus doesn't fiddle with the SIGPIPE handlers */
 494         dbus_connection_set_change_sigpipe(FALSE);
 495
 496         /* Open the logging devices, if possible and necessary */
 497         log_open_syslog();
 498         log_open_kmsg();
 499
 500         /* Make sure we leave a core dump without panicing the
 501          * kernel. */
 502         if (getpid() == 1)
 503                 install_crash_handler();
 504
 505         log_debug("systemd running in %s mode.", manager_running_as_to_string(running_as));
 506
 507         if (running_as == MANAGER_INIT)
 508                 hostname_setup();
 509
 510         if ((r = manager_new(running_as, confirm_spawn, &m)) < 0) {
 511                 log_error("Failed to allocate manager object: %s", strerror(-r));
 512                 goto finish;
 513         }
 514
 515         if ((r = manager_coldplug(m)) < 0) {
 516                 log_error("Failed to retrieve coldplug information: %s", strerror(-r));
 517                 goto finish;
 518         }
 519
 520         log_debug("Activating default unit: %s", default_unit);
 521
 522         if ((r = manager_load_unit(m, default_unit, &target)) < 0) {
 523                 log_error("Failed to load default target: %s", strerror(-r));
 524
 525                 log_info("Trying to load rescue target...");
 526                 if ((r = manager_load_unit(m, SPECIAL_RESCUE_TARGET, &target)) < 0) {
 527                         log_error("Failed to load rescue target: %s", strerror(-r));
 528                         goto finish;
 529                 }
 530         }
 531
 532         if (action == ACTION_TEST) {
 533                 printf("→ By units:\n");
 534                 manager_dump_units(m, stdout, "\t");
 535         }
 536
 537         if ((r = manager_add_job(m, JOB_START, target, JOB_REPLACE, false, &job)) < 0) {
 538                 log_error("Failed to start default target: %s", strerror(-r));
 539                 goto finish;
 540         }
 541
 542         if (action == ACTION_TEST) {
 543                 printf("→ By jobs:\n");
 544                 manager_dump_jobs(m, stdout, "\t");
 545
 546                 if (getpid() == 1)
 547                         pause();
 548
 549                 retval = 0;
 550                 goto finish;
 551         }
 552
 553         if ((r = manager_loop(m)) < 0) {
 554                 log_error("Failed to run mainloop: %s", strerror(-r));
 555                 goto finish;
 556         }
 557
 558         retval = 0;
 559
 560         log_debug("Exit.");
 561
 562 finish:
 563         if (m)
 564                 manager_free(m);
 565
 566         free(default_unit);
 567
 568         dbus_shutdown();
 569
 570         return retval;
 571 }