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 static void nop_handler(int sig) {
  63 }
  64
  65 _noreturn static void crash(int sig) {
  66
  67         if (!dump_core)
  68                 log_error("Caught <%s>, not dumping core.", strsignal(sig));
  69         else {
  70                 struct sigaction sa;
  71                 pid_t pid;
  72
  73                 /* We want to wait for the core process, hence let's enable SIGCHLD */
  74                 zero(sa);
  75                 sa.sa_handler = nop_handler;
  76                 sa.sa_flags = SA_NOCLDSTOP|SA_RESTART;
  77                 assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
  78
  79                 if ((pid = fork()) < 0)
  80                         log_error("Caught <%s>, cannot fork for core dump: %s", strsignal(sig), strerror(errno));
  81
  82                 else if (pid == 0) {
  83                         struct rlimit rl;
  84
  85                         /* Enable default signal handler for core dump */
  86                         zero(sa);
  87                         sa.sa_handler = SIG_DFL;
  88                         assert_se(sigaction(sig, &sa, NULL) == 0);
  89
  90                         /* Don't limit the core dump size */
  91                         zero(rl);
  92                         rl.rlim_cur = RLIM_INFINITY;
  93                         rl.rlim_max = RLIM_INFINITY;
  94                         setrlimit(RLIMIT_CORE, &rl);
  95
  96                         /* Just to be sure... */
  97                         assert_se(chdir("/") == 0);
  98
  99                         /* Raise the signal again */
 100                         raise(sig);
 101
 102                         assert_not_reached("We shouldn't be here...");
 103                         _exit(1);
 104
 105                 } else {
 106                         int status, r;
 107
 108                         /* Order things nicely. */
 109                         if ((r = waitpid(pid, &status, 0)) < 0)
 110                                 log_error("Caught <%s>, waitpid() failed: %s", strsignal(sig), strerror(errno));
 111                         else if (!WCOREDUMP(status))
 112                                 log_error("Caught <%s>, core dump failed.", strsignal(sig));
 113                         else
 114                                 log_error("Caught <%s>, dumped core as pid %llu.", strsignal(sig), (unsigned long long) pid);
 115                 }
 116         }
 117
 118         if (crash_chvt)
 119                 chvt(crash_chvt);
 120
 121         if (crash_shell) {
 122                 struct sigaction sa;
 123                 pid_t pid;
 124
 125                 log_info("Executing crash shell in 10s...");
 126                 sleep(10);
 127
 128                 /* Let the kernel reap children for us */
 129                 zero(sa);
 130                 sa.sa_handler = SIG_IGN;
 131                 sa.sa_flags = SA_NOCLDSTOP|SA_NOCLDWAIT|SA_RESTART;
 132                 assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
 133
 134                 if ((pid = fork()) < 0)
 135                         log_error("Failed to fork off crash shell: %s", strerror(errno));
 136                 else if (pid == 0) {
 137                         execl("/bin/sh", "/bin/sh", NULL);
 138
 139                         log_error("execl() failed: %s", strerror(errno));
 140                         _exit(1);
 141                 }
 142
 143                 log_info("Successfully spawned crash shall as pid %llu.", (unsigned long long) pid);
 144         }
 145
 146         log_info("Freezing execution.");
 147         freeze();
 148 }
 149
 150 static void install_crash_handler(void) {
 151         struct sigaction sa;
 152
 153         zero(sa);
 154
 155         sa.sa_handler = crash;
 156         sa.sa_flags = SA_NODEFER;
 157
 158         assert_se(sigaction(SIGSEGV, &sa, NULL) == 0);
 159         assert_se(sigaction(SIGILL, &sa, NULL) == 0);
 160         assert_se(sigaction(SIGFPE, &sa, NULL) == 0);
 161         assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
 162         assert_se(sigaction(SIGQUIT, &sa, NULL) == 0);
 163         assert_se(sigaction(SIGABRT, &sa, NULL) == 0);
 164 }
 165
 166 static int console_setup(void) {
 167         int tty_fd = -1, null_fd = -1, r = 0;
 168
 169         /* If we are init, we connect stdout/stderr to /dev/console
 170          * and stdin to /dev/null and make sure we don't have a
 171          * controlling tty. */
 172
 173         release_terminal();
 174
 175         if ((tty_fd = open_terminal("/dev/console", O_WRONLY)) < 0) {
 176                 log_error("Failed to open /dev/console: %s", strerror(-tty_fd));
 177                 r = -tty_fd;
 178                 goto finish;
 179         }
 180
 181         if ((null_fd = open("/dev/null", O_RDONLY)) < 0) {
 182                 log_error("Failed to open /dev/null: %m");
 183                 r = -errno;
 184                 goto finish;
 185         }
 186
 187         assert(tty_fd >= 3);
 188         assert(null_fd >= 3);
 189
 190         if (reset_terminal(tty_fd) < 0)
 191                 log_error("Failed to reset /dev/console: %m");
 192
 193         if (dup2(tty_fd, STDOUT_FILENO) < 0 ||
 194             dup2(tty_fd, STDERR_FILENO) < 0 ||
 195             dup2(null_fd, STDIN_FILENO) < 0) {
 196                 log_error("Failed to dup2() device: %m");
 197                 r = -errno;
 198                 goto finish;
 199         }
 200
 201         r = 0;
 202
 203 finish:
 204         if (tty_fd >= 0)
 205                 close_nointr(tty_fd);
 206
 207         if (null_fd >= 0)
 208                 close_nointr(null_fd);
 209
 210         return r;
 211 }
 212
 213 static int set_default_unit(const char *u) {
 214         char *c;
 215
 216         assert(u);
 217
 218         if (!(c = strdup(u)))
 219                 return -ENOMEM;
 220
 221         free(default_unit);
 222         default_unit = c;
 223         return 0;
 224 }
 225
 226 static int parse_proc_cmdline_word(const char *word) {
 227
 228         static const char * const rlmap[] = {
 229                 "single", SPECIAL_RUNLEVEL1_TARGET,
 230                 "-s",     SPECIAL_RUNLEVEL1_TARGET,
 231                 "s",      SPECIAL_RUNLEVEL1_TARGET,
 232                 "S",      SPECIAL_RUNLEVEL1_TARGET,
 233                 "1",      SPECIAL_RUNLEVEL1_TARGET,
 234                 "2",      SPECIAL_RUNLEVEL2_TARGET,
 235                 "3",      SPECIAL_RUNLEVEL3_TARGET,
 236                 "4",      SPECIAL_RUNLEVEL4_TARGET,
 237                 "5",      SPECIAL_RUNLEVEL5_TARGET
 238         };
 239
 240         if (startswith(word, "systemd.default="))
 241                 return set_default_unit(word + 16);
 242
 243         else if (startswith(word, "systemd.log_target=")) {
 244
 245                 if (log_set_target_from_string(word + 19) < 0)
 246                         log_warning("Failed to parse log target %s. Ignoring.", word + 19);
 247
 248         } else if (startswith(word, "systemd.log_level=")) {
 249
 250                 if (log_set_max_level_from_string(word + 18) < 0)
 251                         log_warning("Failed to parse log level %s. Ignoring.", word + 18);
 252
 253         } else if (startswith(word, "systemd.dump_core=")) {
 254                 int r;
 255
 256                 if ((r = parse_boolean(word + 18)) < 0)
 257                         log_warning("Failed to parse dump core switch %s, Ignoring.", word + 18);
 258                 else
 259                         dump_core = r;
 260
 261         } else if (startswith(word, "systemd.crash_shell=")) {
 262                 int r;
 263
 264                 if ((r = parse_boolean(word + 20)) < 0)
 265                         log_warning("Failed to parse crash shell switch %s, Ignoring.", word + 20);
 266                 else
 267                         crash_shell = r;
 268
 269
 270         } else if (startswith(word, "systemd.confirm_spawn=")) {
 271                 int r;
 272
 273                 if ((r = parse_boolean(word + 22)) < 0)
 274                         log_warning("Failed to parse confirm spawn switch %s, Ignoring.", word + 22);
 275                 else
 276                         confirm_spawn = r;
 277
 278         } else if (startswith(word, "systemd.crash_chvt=")) {
 279                 int k;
 280
 281                 if (safe_atoi(word + 19, &k) < 0)
 282                         log_warning("Failed to parse crash chvt switch %s, Ignoring.", word + 19);
 283                 else
 284                         crash_chvt = k;
 285
 286         } else if (startswith(word, "systemd.")) {
 287
 288                 log_warning("Unknown kernel switch %s. Ignoring.", word);
 289
 290                 log_info("Supported kernel switches:");
 291                 log_info("systemd.default=UNIT                     Default unit to start");
 292                 log_info("systemd.log_target=console|kmsg|syslog   Log target");
 293                 log_info("systemd.log_level=LEVEL                  Log level");
 294                 log_info("systemd.dump_core=0|1                    Dump core on crash");
 295                 log_info("systemd.crash_shell=0|1                  On crash run shell");
 296                 log_info("systemd.crash_chvt=N                     Change to VT #N on crash");
 297                 log_info("systemd.confirm_spawn=0|1                Confirm every process spawn");
 298
 299         } else {
 300                 unsigned i;
 301
 302                 /* SysV compatibility */
 303                 for (i = 0; i < ELEMENTSOF(rlmap); i += 2)
 304                         if (streq(word, rlmap[i]))
 305                                 return set_default_unit(rlmap[i+1]);
 306         }
 307
 308         return 0;
 309 }
 310
 311 static int parse_proc_cmdline(void) {
 312         char *line;
 313         int r;
 314         char *w;
 315         size_t l;
 316         char *state;
 317
 318         if ((r = read_one_line_file("/proc/cmdline", &line)) < 0) {
 319                 log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(errno));
 320                 return 0;
 321         }
 322
 323         FOREACH_WORD_QUOTED(w, l, line, state) {
 324                 char *word;
 325
 326                 if (!(word = strndup(w, l))) {
 327                         r = -ENOMEM;
 328                         goto finish;
 329                 }
 330
 331                 r = parse_proc_cmdline_word(word);
 332                 free(word);
 333
 334                 if (r < 0)
 335                         goto finish;
 336         }
 337
 338         r = 0;
 339
 340 finish:
 341         free(line);
 342         return r;
 343 }
 344
 345 static int parse_argv(int argc, char *argv[]) {
 346
 347         enum {
 348                 ARG_LOG_LEVEL = 0x100,
 349                 ARG_LOG_TARGET,
 350                 ARG_DEFAULT,
 351                 ARG_RUNNING_AS,
 352                 ARG_TEST,
 353                 ARG_DUMP_CONFIGURATION_ITEMS,
 354                 ARG_CONFIRM_SPAWN
 355         };
 356
 357         static const struct option options[] = {
 358                 { "log-level",  required_argument, NULL, ARG_LOG_LEVEL },
 359                 { "log-target", required_argument, NULL, ARG_LOG_TARGET },
 360                 { "default",    required_argument, NULL, ARG_DEFAULT },
 361                 { "running-as", required_argument, NULL, ARG_RUNNING_AS },
 362                 { "test",       no_argument,       NULL, ARG_TEST },
 363                 { "help",       no_argument,       NULL, 'h' },
 364                 { "dump-configuration-items", no_argument, NULL, ARG_DUMP_CONFIGURATION_ITEMS },
 365                 { "confirm-spawn", no_argument,    NULL, ARG_CONFIRM_SPAWN },
 366                 { NULL,         0,                 NULL, 0 }
 367         };
 368
 369         int c, r;
 370
 371         assert(argc >= 1);
 372         assert(argv);
 373
 374         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
 375
 376                 switch (c) {
 377
 378                 case ARG_LOG_LEVEL:
 379                         if ((r = log_set_max_level_from_string(optarg)) < 0) {
 380                                 log_error("Failed to parse log level %s.", optarg);
 381                                 return r;
 382                         }
 383
 384                         break;
 385
 386                 case ARG_LOG_TARGET:
 387
 388                         if ((r = log_set_target_from_string(optarg)) < 0) {
 389                                 log_error("Failed to parse log target %s.", optarg);
 390                                 return r;
 391                         }
 392
 393                         break;
 394
 395                 case ARG_DEFAULT:
 396
 397                         if ((r = set_default_unit(optarg)) < 0) {
 398                                 log_error("Failed to set default unit %s: %s", optarg, strerror(-r));
 399                                 return r;
 400                         }
 401
 402                         break;
 403
 404                 case ARG_RUNNING_AS: {
 405                         ManagerRunningAs as;
 406
 407                         if ((as = manager_running_as_from_string(optarg)) < 0) {
 408                                 log_error("Failed to parse running as value %s", optarg);
 409                                 return -EINVAL;
 410                         }
 411
 412                         running_as = as;
 413                         break;
 414                 }
 415
 416                 case ARG_TEST:
 417                         action = ACTION_TEST;
 418                         break;
 419
 420                 case ARG_DUMP_CONFIGURATION_ITEMS:
 421                         action = ACTION_DUMP_CONFIGURATION_ITEMS;
 422                         break;
 423
 424                 case ARG_CONFIRM_SPAWN:
 425                         confirm_spawn = true;
 426                         break;
 427
 428                 case 'h':
 429                         action = ACTION_HELP;
 430                         break;
 431
 432                 case '?':
 433                         return -EINVAL;
 434
 435                 default:
 436                         log_error("Unknown option code %c", c);
 437                         return -EINVAL;
 438                 }
 439
 440         return 0;
 441 }
 442
 443 static int help(void) {
 444
 445         printf("%s [options]\n\n"
 446                "  -h --help                      Show this help\n"
 447                "     --default=UNIT              Set default unit\n"
 448                "     --log-level=LEVEL           Set log level\n"
 449                "     --log-target=TARGET         Set log target (console, syslog, kmsg)\n"
 450                "     --running-as=AS             Set running as (init, system, session)\n"
 451                "     --test                      Determine startup sequence, dump it and exit\n"
 452                "     --dump-configuration-items  Dump understood unit configuration items\n"
 453                "     --confirm-spawn             Ask for confirmation when spawning processes\n",
 454                __progname);
 455
 456         return 0;
 457 }
 458
 459 int main(int argc, char *argv[]) {
 460         Manager *m = NULL;
 461         Unit *target = NULL;
 462         Job *job = NULL;
 463         int r, retval = 1;
 464
 465         if (getpid() == 1)
 466                 running_as = MANAGER_INIT;
 467         else if (getuid() == 0)
 468                 running_as = MANAGER_SYSTEM;
 469         else
 470                 running_as = MANAGER_SESSION;
 471
 472         if (set_default_unit(SPECIAL_DEFAULT_TARGET) < 0)
 473                 goto finish;
 474
 475         /* Mount /proc, /sys and friends, so that /proc/cmdline and
 476          * /proc/$PID/fd is available. */
 477         if (mount_setup() < 0)
 478                 goto finish;
 479
 480         /* Reset all signal handlers. */
 481         assert_se(reset_all_signal_handlers() == 0);
 482
 483         /* If we are init, we can block sigkill. Yay. */
 484         ignore_signal(SIGKILL);
 485         ignore_signal(SIGPIPE);
 486
 487         /* Close all open files */
 488         assert_se(close_all_fds(NULL, 0) == 0);
 489
 490         if (running_as != MANAGER_SESSION)
 491                 if (parse_proc_cmdline() < 0)
 492                         goto finish;
 493
 494         log_parse_environment();
 495
 496         if (parse_argv(argc, argv) < 0)
 497                 goto finish;
 498
 499         if (action == ACTION_HELP) {
 500                 retval = help();
 501                 goto finish;
 502         } else if (action == ACTION_DUMP_CONFIGURATION_ITEMS) {
 503                 unit_dump_config_items(stdout);
 504                 retval = 0;
 505                 goto finish;
 506         }
 507
 508         assert_se(action == ACTION_RUN || action == ACTION_TEST);
 509
 510         /* Set up PATH unless it is already set */
 511         setenv("PATH",
 512                "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
 513                running_as == MANAGER_INIT);
 514
 515         /* Move out of the way, so that we won't block unmounts */
 516         assert_se(chdir("/")  == 0);
 517
 518         if (running_as != MANAGER_SESSION) {
 519                 /* Become a session leader if we aren't one yet. */
 520                 setsid();
 521
 522                 /* Disable the umask logic */
 523                 umask(0);
 524         }
 525
 526         if (running_as == MANAGER_INIT)
 527                 console_setup();
 528
 529         /* Make sure D-Bus doesn't fiddle with the SIGPIPE handlers */
 530         dbus_connection_set_change_sigpipe(FALSE);
 531
 532         /* Open the logging devices, if possible and necessary */
 533         log_open_syslog();
 534         log_open_kmsg();
 535
 536         /* Make sure we leave a core dump without panicing the
 537          * kernel. */
 538         if (getpid() == 1)
 539                 install_crash_handler();
 540
 541         log_debug("systemd running in %s mode.", manager_running_as_to_string(running_as));
 542
 543         if (running_as == MANAGER_INIT)
 544                 hostname_setup();
 545
 546         if ((r = manager_new(running_as, confirm_spawn, &m)) < 0) {
 547                 log_error("Failed to allocate manager object: %s", strerror(-r));
 548                 goto finish;
 549         }
 550
 551         if ((r = manager_coldplug(m)) < 0) {
 552                 log_error("Failed to retrieve coldplug information: %s", strerror(-r));
 553                 goto finish;
 554         }
 555
 556         log_debug("Activating default unit: %s", default_unit);
 557
 558         if ((r = manager_load_unit(m, default_unit, NULL, &target)) < 0) {
 559                 log_error("Failed to load default target: %s", strerror(-r));
 560
 561                 log_info("Trying to load rescue target...");
 562                 if ((r = manager_load_unit(m, SPECIAL_RESCUE_TARGET, NULL, &target)) < 0) {
 563                         log_error("Failed to load rescue target: %s", strerror(-r));
 564                         goto finish;
 565                 }
 566         }
 567
 568         if (action == ACTION_TEST) {
 569                 printf("→ By units:\n");
 570                 manager_dump_units(m, stdout, "\t");
 571         }
 572
 573         if ((r = manager_add_job(m, JOB_START, target, JOB_REPLACE, false, &job)) < 0) {
 574                 log_error("Failed to start default target: %s", strerror(-r));
 575                 goto finish;
 576         }
 577
 578         if (action == ACTION_TEST) {
 579                 printf("→ By jobs:\n");
 580                 manager_dump_jobs(m, stdout, "\t");
 581
 582                 if (getpid() == 1)
 583                         pause();
 584
 585                 retval = 0;
 586                 goto finish;
 587         }
 588
 589         if ((r = manager_loop(m)) < 0) {
 590                 log_error("Failed to run mainloop: %s", strerror(-r));
 591                 goto finish;
 592         }
 593
 594         retval = 0;
 595
 596         log_debug("Exit.");
 597
 598 finish:
 599         if (m)
 600                 manager_free(m);
 601
 602         free(default_unit);
 603
 604         dbus_shutdown();
 605
 606         if (getpid() == 1)
 607                 freeze();
 608
 609         return retval;
 610 }