manager.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 <assert.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <sys/epoll.h>
  26 #include <signal.h>
  27 #include <sys/signalfd.h>
  28 #include <sys/wait.h>
  29 #include <unistd.h>
  30 #include <utmpx.h>
  31 #include <sys/poll.h>
  32 #include <sys/reboot.h>
  33 #include <sys/ioctl.h>
  34 #include <linux/kd.h>
  35 #include <libcgroup.h>
  36 #include <termios.h>
  37 #include <fcntl.h>
  38
  39 #include "manager.h"
  40 #include "hashmap.h"
  41 #include "macro.h"
  42 #include "strv.h"
  43 #include "log.h"
  44 #include "util.h"
  45 #include "ratelimit.h"
  46 #include "cgroup.h"
  47 #include "mount-setup.h"
  48 #include "utmp-wtmp.h"
  49 #include "unit-name.h"
  50
  51 static int enable_special_signals(Manager *m) {
  52         char fd;
  53
  54         assert(m);
  55
  56         /* Enable that we get SIGINT on control-alt-del */
  57         if (reboot(RB_DISABLE_CAD) < 0)
  58                 log_warning("Failed to enable ctrl-alt-del handling: %m");
  59
  60         if ((fd = open_terminal("/dev/tty0", O_RDWR)) < 0)
  61                 log_warning("Failed to open /dev/tty0: %m");
  62         else {
  63                 /* Enable that we get SIGWINCH on kbrequest */
  64                 if (ioctl(fd, KDSIGACCEPT, SIGWINCH) < 0)
  65                         log_warning("Failed to enable kbrequest handling: %s", strerror(errno));
  66
  67                 close_nointr_nofail(fd);
  68         }
  69
  70         return 0;
  71 }
  72
  73 static int manager_setup_signals(Manager *m) {
  74         sigset_t mask;
  75         struct epoll_event ev;
  76         struct sigaction sa;
  77
  78         assert(m);
  79
  80         /* We are not interested in SIGSTOP and friends. */
  81         zero(sa);
  82         sa.sa_handler = SIG_DFL;
  83         sa.sa_flags = SA_NOCLDSTOP|SA_RESTART;
  84         assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
  85
  86         assert_se(sigemptyset(&mask) == 0);
  87         assert_se(sigaddset(&mask, SIGCHLD) == 0);
  88         assert_se(sigaddset(&mask, SIGTERM) == 0);
  89         assert_se(sigaddset(&mask, SIGHUP) == 0);
  90         assert_se(sigaddset(&mask, SIGUSR1) == 0);
  91         assert_se(sigaddset(&mask, SIGUSR2) == 0);
  92         assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
  93         assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
  94         assert_se(sigaddset(&mask, SIGPWR) == 0);   /* Some kernel drivers and upsd send us this on power failure */
  95         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
  96
  97         m->signal_watch.type = WATCH_SIGNAL;
  98         if ((m->signal_watch.fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
  99                 return -errno;
 100
 101         zero(ev);
 102         ev.events = EPOLLIN;
 103         ev.data.ptr = &m->signal_watch;
 104
 105         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
 106                 return -errno;
 107
 108         if (m->running_as == MANAGER_INIT)
 109                 return enable_special_signals(m);
 110
 111         return 0;
 112 }
 113
 114 static char** session_dirs(void) {
 115         const char *home, *e;
 116         char *config_home = NULL, *data_home = NULL;
 117         char **config_dirs = NULL, **data_dirs = NULL;
 118         char **r = NULL, **t;
 119
 120         /* Implement the mechanisms defined in
 121          *
 122          * http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html
 123          *
 124          * We look in both the config and the data dirs because we
 125          * want to encourage that distributors ship their unit files
 126          * as data, and allow overriding as configuration.
 127          */
 128
 129         home = getenv("HOME");
 130
 131         if ((e = getenv("XDG_CONFIG_HOME"))) {
 132                 if (asprintf(&config_home, "%s/systemd/session", e) < 0)
 133                         goto fail;
 134
 135         } else if (home) {
 136                 if (asprintf(&config_home, "%s/.config/systemd/session", home) < 0)
 137                         goto fail;
 138         }
 139
 140         if ((e = getenv("XDG_CONFIG_DIRS")))
 141                 config_dirs = strv_split(e, ":");
 142         else
 143                 config_dirs = strv_new("/etc/xdg", NULL);
 144
 145         if (!config_dirs)
 146                 goto fail;
 147
 148         if ((e = getenv("XDG_DATA_HOME"))) {
 149                 if (asprintf(&data_home, "%s/systemd/session", e) < 0)
 150                         goto fail;
 151
 152         } else if (home) {
 153                 if (asprintf(&data_home, "%s/.local/share/systemd/session", home) < 0)
 154                         goto fail;
 155         }
 156
 157         if ((e = getenv("XDG_DATA_DIRS")))
 158                 data_dirs = strv_split(e, ":");
 159         else
 160                 data_dirs = strv_new("/usr/local/share", "/usr/share", NULL);
 161
 162         if (!data_dirs)
 163                 goto fail;
 164
 165         /* Now merge everything we found. */
 166         if (config_home) {
 167                 if (!(t = strv_append(r, config_home)))
 168                         goto fail;
 169                 strv_free(r);
 170                 r = t;
 171         }
 172
 173         if (!(t = strv_merge_concat(r, config_dirs, "/systemd/session")))
 174                 goto finish;
 175         strv_free(r);
 176         r = t;
 177
 178         if (!(t = strv_append(r, SESSION_CONFIG_UNIT_PATH)))
 179                 goto fail;
 180         strv_free(r);
 181         r = t;
 182
 183         if (data_home) {
 184                 if (!(t = strv_append(r, data_home)))
 185                         goto fail;
 186                 strv_free(r);
 187                 r = t;
 188         }
 189
 190         if (!(t = strv_merge_concat(r, data_dirs, "/systemd/session")))
 191                 goto fail;
 192         strv_free(r);
 193         r = t;
 194
 195         if (!(t = strv_append(r, SESSION_DATA_UNIT_PATH)))
 196                 goto fail;
 197         strv_free(r);
 198         r = t;
 199
 200         if (!strv_path_make_absolute_cwd(r))
 201             goto fail;
 202
 203 finish:
 204         free(config_home);
 205         strv_free(config_dirs);
 206         free(data_home);
 207         strv_free(data_dirs);
 208
 209         return r;
 210
 211 fail:
 212         strv_free(r);
 213         r = NULL;
 214         goto finish;
 215 }
 216
 217 static int manager_find_paths(Manager *m) {
 218         const char *e;
 219         char *t;
 220
 221         assert(m);
 222
 223         /* First priority is whatever has been passed to us via env
 224          * vars */
 225         if ((e = getenv("SYSTEMD_UNIT_PATH")))
 226                 if (!(m->unit_path = split_path_and_make_absolute(e)))
 227                         return -ENOMEM;
 228
 229         if (strv_isempty(m->unit_path)) {
 230
 231                 /* Nothing is set, so let's figure something out. */
 232                 strv_free(m->unit_path);
 233
 234                 if (m->running_as == MANAGER_SESSION) {
 235                         if (!(m->unit_path = session_dirs()))
 236                                 return -ENOMEM;
 237                 } else
 238                         if (!(m->unit_path = strv_new(
 239                                               SYSTEM_CONFIG_UNIT_PATH,  /* /etc/systemd/system/ */
 240                                               SYSTEM_DATA_UNIT_PATH,    /* /lib/systemd/system/ */
 241                                               NULL)))
 242                                 return -ENOMEM;
 243         }
 244
 245         if (m->running_as == MANAGER_INIT) {
 246                 /* /etc/init.d/ compativility does not matter to users */
 247
 248                 if ((e = getenv("SYSTEMD_SYSVINIT_PATH")))
 249                         if (!(m->sysvinit_path = split_path_and_make_absolute(e)))
 250                                 return -ENOMEM;
 251
 252                 if (strv_isempty(m->sysvinit_path)) {
 253                         strv_free(m->sysvinit_path);
 254
 255                         if (!(m->sysvinit_path = strv_new(
 256                                               SYSTEM_SYSVINIT_PATH,     /* /etc/init.d/ */
 257                                               NULL)))
 258                                 return -ENOMEM;
 259                 }
 260
 261                 if ((e = getenv("SYSTEMD_SYSVRCND_PATH")))
 262                         if (!(m->sysvrcnd_path = split_path_and_make_absolute(e)))
 263                                 return -ENOMEM;
 264
 265                 if (strv_isempty(m->sysvrcnd_path)) {
 266                         strv_free(m->sysvrcnd_path);
 267
 268                         if (!(m->sysvrcnd_path = strv_new(
 269                                               SYSTEM_SYSVRCND_PATH,     /* /etc/rcN.d/ */
 270                                               NULL)))
 271                                 return -ENOMEM;
 272                 }
 273         }
 274
 275         strv_uniq(m->unit_path);
 276         strv_uniq(m->sysvinit_path);
 277         strv_uniq(m->sysvrcnd_path);
 278
 279         assert(!strv_isempty(m->unit_path));
 280         if (!(t = strv_join(m->unit_path, "\n\t")))
 281                 return -ENOMEM;
 282         log_debug("Looking for unit files in:\n\t%s", t);
 283         free(t);
 284
 285         if (!strv_isempty(m->sysvinit_path)) {
 286
 287                 if (!(t = strv_join(m->sysvinit_path, "\n\t")))
 288                         return -ENOMEM;
 289
 290                 log_debug("Looking for SysV init scripts in:\n\t%s", t);
 291                 free(t);
 292         } else
 293                 log_debug("Ignoring SysV init scripts.");
 294
 295         if (!strv_isempty(m->sysvrcnd_path)) {
 296
 297                 if (!(t = strv_join(m->sysvrcnd_path, "\n\t")))
 298                         return -ENOMEM;
 299
 300                 log_debug("Looking for SysV rcN.d links in:\n\t%s", t);
 301                 free(t);
 302         } else
 303                 log_debug("Ignoring SysV rcN.d links.");
 304
 305         return 0;
 306 }
 307
 308 int manager_new(ManagerRunningAs running_as, bool confirm_spawn, Manager **_m) {
 309         Manager *m;
 310         int r = -ENOMEM;
 311
 312         assert(_m);
 313         assert(running_as >= 0);
 314         assert(running_as < _MANAGER_RUNNING_AS_MAX);
 315
 316         if (!(m = new0(Manager, 1)))
 317                 return -ENOMEM;
 318
 319         m->boot_timestamp = now(CLOCK_REALTIME);
 320
 321         m->running_as = running_as;
 322         m->confirm_spawn = confirm_spawn;
 323
 324         m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = -1;
 325         m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
 326
 327         if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
 328                 goto fail;
 329
 330         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
 331                 goto fail;
 332
 333         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
 334                 goto fail;
 335
 336         if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
 337                 goto fail;
 338
 339         if (!(m->cgroup_bondings = hashmap_new(string_hash_func, string_compare_func)))
 340                 goto fail;
 341
 342         if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
 343                 goto fail;
 344
 345         if ((r = manager_find_paths(m)) < 0)
 346                 goto fail;
 347
 348         if ((r = manager_setup_signals(m)) < 0)
 349                 goto fail;
 350
 351         if ((r = manager_setup_cgroup(m)) < 0)
 352                 goto fail;
 353
 354         /* Try to connect to the busses, if possible. */
 355         if ((r = bus_init_system(m)) < 0 ||
 356             (r = bus_init_api(m)) < 0)
 357                 goto fail;
 358
 359         *_m = m;
 360         return 0;
 361
 362 fail:
 363         manager_free(m);
 364         return r;
 365 }
 366
 367 static unsigned manager_dispatch_cleanup_queue(Manager *m) {
 368         Meta *meta;
 369         unsigned n = 0;
 370
 371         assert(m);
 372
 373         while ((meta = m->cleanup_queue)) {
 374                 assert(meta->in_cleanup_queue);
 375
 376                 unit_free(UNIT(meta));
 377                 n++;
 378         }
 379
 380         return n;
 381 }
 382
 383 void manager_free(Manager *m) {
 384         UnitType c;
 385         Unit *u;
 386         Job *j;
 387
 388         assert(m);
 389
 390         while ((j = hashmap_first(m->transaction_jobs)))
 391                 job_free(j);
 392
 393         while ((u = hashmap_first(m->units)))
 394                 unit_free(u);
 395
 396         manager_dispatch_cleanup_queue(m);
 397
 398         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 399                 if (unit_vtable[c]->shutdown)
 400                         unit_vtable[c]->shutdown(m);
 401
 402         manager_shutdown_cgroup(m);
 403
 404         bus_done_api(m);
 405         bus_done_system(m);
 406
 407         hashmap_free(m->units);
 408         hashmap_free(m->jobs);
 409         hashmap_free(m->transaction_jobs);
 410         hashmap_free(m->watch_pids);
 411
 412         if (m->epoll_fd >= 0)
 413                 close_nointr(m->epoll_fd);
 414         if (m->signal_watch.fd >= 0)
 415                 close_nointr(m->signal_watch.fd);
 416
 417         strv_free(m->unit_path);
 418         strv_free(m->sysvinit_path);
 419         strv_free(m->sysvrcnd_path);
 420
 421         free(m->cgroup_controller);
 422         free(m->cgroup_hierarchy);
 423
 424         assert(hashmap_isempty(m->cgroup_bondings));
 425         hashmap_free(m->cgroup_bondings);
 426
 427         free(m);
 428 }
 429
 430 int manager_coldplug(Manager *m) {
 431         int r;
 432         UnitType c;
 433         Iterator i;
 434         Unit *u;
 435         char *k;
 436
 437         assert(m);
 438
 439         /* First, let's ask every type to load all units from
 440          * disk/kernel that it might know */
 441         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 442                 if (unit_vtable[c]->enumerate)
 443                         if ((r = unit_vtable[c]->enumerate(m)) < 0)
 444                                 return r;
 445
 446         manager_dispatch_load_queue(m);
 447
 448         /* Then, let's set up their initial state. */
 449         HASHMAP_FOREACH_KEY(u, k, m->units, i) {
 450
 451                 /* ignore aliases */
 452                 if (u->meta.id != k)
 453                         continue;
 454
 455                 if (UNIT_VTABLE(u)->coldplug)
 456                         if ((r = UNIT_VTABLE(u)->coldplug(u)) < 0)
 457                                 return r;
 458         }
 459
 460         /* Now that the initial devices are available, let's see if we
 461          * can write the utmp file */
 462         manager_write_utmp_reboot(m);
 463
 464         return 0;
 465 }
 466
 467 static void transaction_delete_job(Manager *m, Job *j, bool delete_dependencies) {
 468         assert(m);
 469         assert(j);
 470
 471         /* Deletes one job from the transaction */
 472
 473         manager_transaction_unlink_job(m, j, delete_dependencies);
 474
 475         if (!j->installed)
 476                 job_free(j);
 477 }
 478
 479 static void transaction_delete_unit(Manager *m, Unit *u) {
 480         Job *j;
 481
 482         /* Deletes all jobs associated with a certain unit from the
 483          * transaction */
 484
 485         while ((j = hashmap_get(m->transaction_jobs, u)))
 486                 transaction_delete_job(m, j, true);
 487 }
 488
 489 static void transaction_clean_dependencies(Manager *m) {
 490         Iterator i;
 491         Job *j;
 492
 493         assert(m);
 494
 495         /* Drops all dependencies of all installed jobs */
 496
 497         HASHMAP_FOREACH(j, m->jobs, i) {
 498                 while (j->subject_list)
 499                         job_dependency_free(j->subject_list);
 500                 while (j->object_list)
 501                         job_dependency_free(j->object_list);
 502         }
 503
 504         assert(!m->transaction_anchor);
 505 }
 506
 507 static void transaction_abort(Manager *m) {
 508         Job *j;
 509
 510         assert(m);
 511
 512         while ((j = hashmap_first(m->transaction_jobs)))
 513                 if (j->installed)
 514                         transaction_delete_job(m, j, true);
 515                 else
 516                         job_free(j);
 517
 518         assert(hashmap_isempty(m->transaction_jobs));
 519
 520         transaction_clean_dependencies(m);
 521 }
 522
 523 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
 524         JobDependency *l;
 525
 526         assert(m);
 527
 528         /* A recursive sweep through the graph that marks all units
 529          * that matter to the anchor job, i.e. are directly or
 530          * indirectly a dependency of the anchor job via paths that
 531          * are fully marked as mattering. */
 532
 533         if (j)
 534                 l = j->subject_list;
 535         else
 536                 l = m->transaction_anchor;
 537
 538         LIST_FOREACH(subject, l, l) {
 539
 540                 /* This link does not matter */
 541                 if (!l->matters)
 542                         continue;
 543
 544                 /* This unit has already been marked */
 545                 if (l->object->generation == generation)
 546                         continue;
 547
 548                 l->object->matters_to_anchor = true;
 549                 l->object->generation = generation;
 550
 551                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
 552         }
 553 }
 554
 555 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 556         JobDependency *l, *last;
 557
 558         assert(j);
 559         assert(other);
 560         assert(j->unit == other->unit);
 561         assert(!j->installed);
 562
 563         /* Merges 'other' into 'j' and then deletes j. */
 564
 565         j->type = t;
 566         j->state = JOB_WAITING;
 567         j->override = j->override || other->override;
 568
 569         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 570
 571         /* Patch us in as new owner of the JobDependency objects */
 572         last = NULL;
 573         LIST_FOREACH(subject, l, other->subject_list) {
 574                 assert(l->subject == other);
 575                 l->subject = j;
 576                 last = l;
 577         }
 578
 579         /* Merge both lists */
 580         if (last) {
 581                 last->subject_next = j->subject_list;
 582                 if (j->subject_list)
 583                         j->subject_list->subject_prev = last;
 584                 j->subject_list = other->subject_list;
 585         }
 586
 587         /* Patch us in as new owner of the JobDependency objects */
 588         last = NULL;
 589         LIST_FOREACH(object, l, other->object_list) {
 590                 assert(l->object == other);
 591                 l->object = j;
 592                 last = l;
 593         }
 594
 595         /* Merge both lists */
 596         if (last) {
 597                 last->object_next = j->object_list;
 598                 if (j->object_list)
 599                         j->object_list->object_prev = last;
 600                 j->object_list = other->object_list;
 601         }
 602
 603         /* Kill the other job */
 604         other->subject_list = NULL;
 605         other->object_list = NULL;
 606         transaction_delete_job(m, other, true);
 607 }
 608
 609 static int delete_one_unmergeable_job(Manager *m, Job *j) {
 610         Job *k;
 611
 612         assert(j);
 613
 614         /* Tries to delete one item in the linked list
 615          * j->transaction_next->transaction_next->... that conflicts
 616          * whith another one, in an attempt to make an inconsistent
 617          * transaction work. */
 618
 619         /* We rely here on the fact that if a merged with b does not
 620          * merge with c, either a or b merge with c neither */
 621         LIST_FOREACH(transaction, j, j)
 622                 LIST_FOREACH(transaction, k, j->transaction_next) {
 623                         Job *d;
 624
 625                         /* Is this one mergeable? Then skip it */
 626                         if (job_type_is_mergeable(j->type, k->type))
 627                                 continue;
 628
 629                         /* Ok, we found two that conflict, let's see if we can
 630                          * drop one of them */
 631                         if (!j->matters_to_anchor)
 632                                 d = j;
 633                         else if (!k->matters_to_anchor)
 634                                 d = k;
 635                         else
 636                                 return -ENOEXEC;
 637
 638                         /* Ok, we can drop one, so let's do so. */
 639                         log_debug("Trying to fix job merging by deleting job %s/%s", d->unit->meta.id, job_type_to_string(d->type));
 640                         transaction_delete_job(m, d, true);
 641                         return 0;
 642                 }
 643
 644         return -EINVAL;
 645 }
 646
 647 static int transaction_merge_jobs(Manager *m) {
 648         Job *j;
 649         Iterator i;
 650         int r;
 651
 652         assert(m);
 653
 654         /* First step, check whether any of the jobs for one specific
 655          * task conflict. If so, try to drop one of them. */
 656         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 657                 JobType t;
 658                 Job *k;
 659
 660                 t = j->type;
 661                 LIST_FOREACH(transaction, k, j->transaction_next) {
 662                         if ((r = job_type_merge(&t, k->type)) >= 0)
 663                                 continue;
 664
 665                         /* OK, we could not merge all jobs for this
 666                          * action. Let's see if we can get rid of one
 667                          * of them */
 668
 669                         if ((r = delete_one_unmergeable_job(m, j)) >= 0)
 670                                 /* Ok, we managed to drop one, now
 671                                  * let's ask our callers to call us
 672                                  * again after garbage collecting */
 673                                 return -EAGAIN;
 674
 675                         /* We couldn't merge anything. Failure */
 676                         return r;
 677                 }
 678         }
 679
 680         /* Second step, merge the jobs. */
 681         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 682                 JobType t = j->type;
 683                 Job *k;
 684
 685                 /* Merge all transactions */
 686                 LIST_FOREACH(transaction, k, j->transaction_next)
 687                         assert_se(job_type_merge(&t, k->type) == 0);
 688
 689                 /* If an active job is mergeable, merge it too */
 690                 if (j->unit->meta.job)
 691                         job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
 692
 693                 while ((k = j->transaction_next)) {
 694                         if (j->installed) {
 695                                 transaction_merge_and_delete_job(m, k, j, t);
 696                                 j = k;
 697                         } else
 698                                 transaction_merge_and_delete_job(m, j, k, t);
 699                 }
 700
 701                 assert(!j->transaction_next);
 702                 assert(!j->transaction_prev);
 703         }
 704
 705         return 0;
 706 }
 707
 708 static void transaction_drop_redundant(Manager *m) {
 709         bool again;
 710
 711         assert(m);
 712
 713         /* Goes through the transaction and removes all jobs that are
 714          * a noop */
 715
 716         do {
 717                 Job *j;
 718                 Iterator i;
 719
 720                 again = false;
 721
 722                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 723                         bool changes_something = false;
 724                         Job *k;
 725
 726                         LIST_FOREACH(transaction, k, j) {
 727
 728                                 if (!job_is_anchor(k) &&
 729                                     job_type_is_redundant(k->type, unit_active_state(k->unit)))
 730                                         continue;
 731
 732                                 changes_something = true;
 733                                 break;
 734                         }
 735
 736                         if (changes_something)
 737                                 continue;
 738
 739                         log_debug("Found redundant job %s/%s, dropping.", j->unit->meta.id, job_type_to_string(j->type));
 740                         transaction_delete_job(m, j, false);
 741                         again = true;
 742                         break;
 743                 }
 744
 745         } while (again);
 746 }
 747
 748 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 749         assert(u);
 750         assert(!j->transaction_prev);
 751
 752         /* Checks whether at least one of the jobs for this unit
 753          * matters to the anchor. */
 754
 755         LIST_FOREACH(transaction, j, j)
 756                 if (j->matters_to_anchor)
 757                         return true;
 758
 759         return false;
 760 }
 761
 762 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 763         Iterator i;
 764         Unit *u;
 765         int r;
 766
 767         assert(m);
 768         assert(j);
 769         assert(!j->transaction_prev);
 770
 771         /* Does a recursive sweep through the ordering graph, looking
 772          * for a cycle. If we find cycle we try to break it. */
 773
 774         /* Did we find a cycle? */
 775         if (j->marker && j->generation == generation) {
 776                 Job *k;
 777
 778                 /* So, we already have been here. We have a
 779                  * cycle. Let's try to break it. We go backwards in
 780                  * our path and try to find a suitable job to
 781                  * remove. We use the marker to find our way back,
 782                  * since smart how we are we stored our way back in
 783                  * there. */
 784
 785                 log_debug("Found ordering cycle on %s/%s", j->unit->meta.id, job_type_to_string(j->type));
 786
 787                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 788
 789                         log_debug("Walked on cycle path to %s/%s", k->unit->meta.id, job_type_to_string(k->type));
 790
 791                         if (!k->installed &&
 792                             !unit_matters_to_anchor(k->unit, k)) {
 793                                 /* Ok, we can drop this one, so let's
 794                                  * do so. */
 795                                 log_debug("Breaking order cycle by deleting job %s/%s", k->unit->meta.id, job_type_to_string(k->type));
 796                                 transaction_delete_unit(m, k->unit);
 797                                 return -EAGAIN;
 798                         }
 799
 800                         /* Check if this in fact was the beginning of
 801                          * the cycle */
 802                         if (k == j)
 803                                 break;
 804                 }
 805
 806                 log_debug("Unable to break cycle");
 807
 808                 return -ENOEXEC;
 809         }
 810
 811         /* Make the marker point to where we come from, so that we can
 812          * find our way backwards if we want to break a cycle */
 813         j->marker = from;
 814         j->generation = generation;
 815
 816         /* We assume that the the dependencies are bidirectional, and
 817          * hence can ignore UNIT_AFTER */
 818         SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
 819                 Job *o;
 820
 821                 /* Is there a job for this unit? */
 822                 if (!(o = hashmap_get(m->transaction_jobs, u)))
 823
 824                         /* Ok, there is no job for this in the
 825                          * transaction, but maybe there is already one
 826                          * running? */
 827                         if (!(o = u->meta.job))
 828                                 continue;
 829
 830                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 831                         return r;
 832         }
 833
 834         /* Ok, let's backtrack, and remember that this entry is not on
 835          * our path anymore. */
 836         j->marker = NULL;
 837
 838         return 0;
 839 }
 840
 841 static int transaction_verify_order(Manager *m, unsigned *generation) {
 842         Job *j;
 843         int r;
 844         Iterator i;
 845
 846         assert(m);
 847         assert(generation);
 848
 849         /* Check if the ordering graph is cyclic. If it is, try to fix
 850          * that up by dropping one of the jobs. */
 851
 852         HASHMAP_FOREACH(j, m->transaction_jobs, i)
 853                 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
 854                         return r;
 855
 856         return 0;
 857 }
 858
 859 static void transaction_collect_garbage(Manager *m) {
 860         bool again;
 861
 862         assert(m);
 863
 864         /* Drop jobs that are not required by any other job */
 865
 866         do {
 867                 Iterator i;
 868                 Job *j;
 869
 870                 again = false;
 871
 872                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 873                         if (j->object_list)
 874                                 continue;
 875
 876                         log_debug("Garbage collecting job %s/%s", j->unit->meta.id, job_type_to_string(j->type));
 877                         transaction_delete_job(m, j, true);
 878                         again = true;
 879                         break;
 880                 }
 881
 882         } while (again);
 883 }
 884
 885 static int transaction_is_destructive(Manager *m, JobMode mode) {
 886         Iterator i;
 887         Job *j;
 888
 889         assert(m);
 890
 891         /* Checks whether applying this transaction means that
 892          * existing jobs would be replaced */
 893
 894         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 895
 896                 /* Assume merged */
 897                 assert(!j->transaction_prev);
 898                 assert(!j->transaction_next);
 899
 900                 if (j->unit->meta.job &&
 901                     j->unit->meta.job != j &&
 902                     !job_type_is_superset(j->type, j->unit->meta.job->type))
 903                         return -EEXIST;
 904         }
 905
 906         return 0;
 907 }
 908
 909 static void transaction_minimize_impact(Manager *m) {
 910         bool again;
 911         assert(m);
 912
 913         /* Drops all unnecessary jobs that reverse already active jobs
 914          * or that stop a running service. */
 915
 916         do {
 917                 Job *j;
 918                 Iterator i;
 919
 920                 again = false;
 921
 922                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 923                         LIST_FOREACH(transaction, j, j) {
 924                                 bool stops_running_service, changes_existing_job;
 925
 926                                 /* If it matters, we shouldn't drop it */
 927                                 if (j->matters_to_anchor)
 928                                         continue;
 929
 930                                 /* Would this stop a running service?
 931                                  * Would this change an existing job?
 932                                  * If so, let's drop this entry */
 933
 934                                 stops_running_service =
 935                                         j->type == JOB_STOP && UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(j->unit));
 936
 937                                 changes_existing_job =
 938                                         j->unit->meta.job && job_type_is_conflicting(j->type, j->unit->meta.job->state);
 939
 940                                 if (!stops_running_service && !changes_existing_job)
 941                                         continue;
 942
 943                                 if (stops_running_service)
 944                                         log_debug("%s/%s would stop a running service.", j->unit->meta.id, job_type_to_string(j->type));
 945
 946                                 if (changes_existing_job)
 947                                         log_debug("%s/%s would change existing job.", j->unit->meta.id, job_type_to_string(j->type));
 948
 949                                 /* Ok, let's get rid of this */
 950                                 log_debug("Deleting %s/%s to minimize impact.", j->unit->meta.id, job_type_to_string(j->type));
 951
 952                                 transaction_delete_job(m, j, true);
 953                                 again = true;
 954                                 break;
 955                         }
 956
 957                         if (again)
 958                                 break;
 959                 }
 960
 961         } while (again);
 962 }
 963
 964 static int transaction_apply(Manager *m, JobMode mode) {
 965         Iterator i;
 966         Job *j;
 967         int r;
 968
 969         /* Moves the transaction jobs to the set of active jobs */
 970
 971         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 972                 /* Assume merged */
 973                 assert(!j->transaction_prev);
 974                 assert(!j->transaction_next);
 975
 976                 if (j->installed)
 977                         continue;
 978
 979                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 980                         goto rollback;
 981         }
 982
 983         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 984                 if (j->installed)
 985                         continue;
 986
 987                 if (j->unit->meta.job)
 988                         job_free(j->unit->meta.job);
 989
 990                 j->unit->meta.job = j;
 991                 j->installed = true;
 992
 993                 /* We're fully installed. Now let's free data we don't
 994                  * need anymore. */
 995
 996                 assert(!j->transaction_next);
 997                 assert(!j->transaction_prev);
 998
 999                 job_add_to_run_queue(j);
1000                 job_add_to_dbus_queue(j);
1001         }
1002
1003         /* As last step, kill all remaining job dependencies. */
1004         transaction_clean_dependencies(m);
1005
1006         return 0;
1007
1008 rollback:
1009
1010         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
1011                 if (j->installed)
1012                         continue;
1013
1014                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
1015         }
1016
1017         return r;
1018 }
1019
1020 static int transaction_activate(Manager *m, JobMode mode) {
1021         int r;
1022         unsigned generation = 1;
1023
1024         assert(m);
1025
1026         /* This applies the changes recorded in transaction_jobs to
1027          * the actual list of jobs, if possible. */
1028
1029         /* First step: figure out which jobs matter */
1030         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
1031
1032         /* Second step: Try not to stop any running services if
1033          * we don't have to. Don't try to reverse running
1034          * jobs if we don't have to. */
1035         transaction_minimize_impact(m);
1036
1037         /* Third step: Drop redundant jobs */
1038         transaction_drop_redundant(m);
1039
1040         for (;;) {
1041                 /* Fourth step: Let's remove unneeded jobs that might
1042                  * be lurking. */
1043                 transaction_collect_garbage(m);
1044
1045                 /* Fifth step: verify order makes sense and correct
1046                  * cycles if necessary and possible */
1047                 if ((r = transaction_verify_order(m, &generation)) >= 0)
1048                         break;
1049
1050                 if (r != -EAGAIN) {
1051                         log_debug("Requested transaction contains an unfixable cyclic ordering dependency: %s", strerror(-r));
1052                         goto rollback;
1053                 }
1054
1055                 /* Let's see if the resulting transaction ordering
1056                  * graph is still cyclic... */
1057         }
1058
1059         for (;;) {
1060                 /* Sixth step: let's drop unmergeable entries if
1061                  * necessary and possible, merge entries we can
1062                  * merge */
1063                 if ((r = transaction_merge_jobs(m)) >= 0)
1064                         break;
1065
1066                 if (r != -EAGAIN) {
1067                         log_debug("Requested transaction contains unmergable jobs: %s", strerror(-r));
1068                         goto rollback;
1069                 }
1070
1071                 /* Seventh step: an entry got dropped, let's garbage
1072                  * collect its dependencies. */
1073                 transaction_collect_garbage(m);
1074
1075                 /* Let's see if the resulting transaction still has
1076                  * unmergeable entries ... */
1077         }
1078
1079         /* Eights step: Drop redundant jobs again, if the merging now allows us to drop more. */
1080         transaction_drop_redundant(m);
1081
1082         /* Ninth step: check whether we can actually apply this */
1083         if (mode == JOB_FAIL)
1084                 if ((r = transaction_is_destructive(m, mode)) < 0) {
1085                         log_debug("Requested transaction contradicts existing jobs: %s", strerror(-r));
1086                         goto rollback;
1087                 }
1088
1089         /* Tenth step: apply changes */
1090         if ((r = transaction_apply(m, mode)) < 0) {
1091                 log_debug("Failed to apply transaction: %s", strerror(-r));
1092                 goto rollback;
1093         }
1094
1095         assert(hashmap_isempty(m->transaction_jobs));
1096         assert(!m->transaction_anchor);
1097
1098         return 0;
1099
1100 rollback:
1101         transaction_abort(m);
1102         return r;
1103 }
1104
1105 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool override, bool *is_new) {
1106         Job *j, *f;
1107         int r;
1108
1109         assert(m);
1110         assert(unit);
1111
1112         /* Looks for an axisting prospective job and returns that. If
1113          * it doesn't exist it is created and added to the prospective
1114          * jobs list. */
1115
1116         f = hashmap_get(m->transaction_jobs, unit);
1117
1118         LIST_FOREACH(transaction, j, f) {
1119                 assert(j->unit == unit);
1120
1121                 if (j->type == type) {
1122                         if (is_new)
1123                                 *is_new = false;
1124                         return j;
1125                 }
1126         }
1127
1128         if (unit->meta.job && unit->meta.job->type == type)
1129                 j = unit->meta.job;
1130         else if (!(j = job_new(m, type, unit)))
1131                 return NULL;
1132
1133         j->generation = 0;
1134         j->marker = NULL;
1135         j->matters_to_anchor = false;
1136         j->override = override;
1137
1138         LIST_PREPEND(Job, transaction, f, j);
1139
1140         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
1141                 job_free(j);
1142                 return NULL;
1143         }
1144
1145         if (is_new)
1146                 *is_new = true;
1147
1148         log_debug("Added job %s/%s to transaction.", unit->meta.id, job_type_to_string(type));
1149
1150         return j;
1151 }
1152
1153 void manager_transaction_unlink_job(Manager *m, Job *j, bool delete_dependencies) {
1154         assert(m);
1155         assert(j);
1156
1157         if (j->transaction_prev)
1158                 j->transaction_prev->transaction_next = j->transaction_next;
1159         else if (j->transaction_next)
1160                 hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
1161         else
1162                 hashmap_remove_value(m->transaction_jobs, j->unit, j);
1163
1164         if (j->transaction_next)
1165                 j->transaction_next->transaction_prev = j->transaction_prev;
1166
1167         j->transaction_prev = j->transaction_next = NULL;
1168
1169         while (j->subject_list)
1170                 job_dependency_free(j->subject_list);
1171
1172         while (j->object_list) {
1173                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
1174
1175                 job_dependency_free(j->object_list);
1176
1177                 if (other && delete_dependencies) {
1178                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
1179                                   other->unit->meta.id, job_type_to_string(other->type),
1180                                   j->unit->meta.id, job_type_to_string(j->type));
1181                         transaction_delete_job(m, other, delete_dependencies);
1182                 }
1183         }
1184 }
1185
1186 static int transaction_add_job_and_dependencies(
1187                 Manager *m,
1188                 JobType type,
1189                 Unit *unit,
1190                 Job *by,
1191                 bool matters,
1192                 bool override,
1193                 Job **_ret) {
1194         Job *ret;
1195         Iterator i;
1196         Unit *dep;
1197         int r;
1198         bool is_new;
1199
1200         assert(m);
1201         assert(type < _JOB_TYPE_MAX);
1202         assert(unit);
1203
1204         if (unit->meta.load_state != UNIT_LOADED)
1205                 return -EINVAL;
1206
1207         if (!unit_job_is_applicable(unit, type))
1208                 return -EBADR;
1209
1210         /* First add the job. */
1211         if (!(ret = transaction_add_one_job(m, type, unit, override, &is_new)))
1212                 return -ENOMEM;
1213
1214         /* Then, add a link to the job. */
1215         if (!job_dependency_new(by, ret, matters))
1216                 return -ENOMEM;
1217
1218         if (is_new) {
1219                 /* Finally, recursively add in all dependencies. */
1220                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
1221                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
1222                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
1223                                         goto fail;
1224
1225                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES_OVERRIDABLE], i)
1226                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !override, override, NULL)) < 0 && r != -EBADR)
1227                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, strerror(-r));
1228
1229                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
1230                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, false, NULL)) < 0)
1231                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, strerror(-r));
1232
1233                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
1234                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
1235                                         goto fail;
1236
1237                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE_OVERRIDABLE], i)
1238                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !override, override, NULL)) < 0 && r != -EBADR)
1239                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->meta.id, strerror(-r));
1240
1241                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
1242                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
1243                                         goto fail;
1244
1245                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
1246
1247                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
1248                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, override, NULL)) < 0 && r != -EBADR)
1249                                         goto fail;
1250                 }
1251
1252                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
1253         }
1254
1255         if (_ret)
1256                 *_ret = ret;
1257
1258         return 0;
1259
1260 fail:
1261         return r;
1262 }
1263
1264 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool override, Job **_ret) {
1265         int r;
1266         Job *ret;
1267
1268         assert(m);
1269         assert(type < _JOB_TYPE_MAX);
1270         assert(unit);
1271         assert(mode < _JOB_MODE_MAX);
1272
1273         log_debug("Trying to enqueue job %s/%s", unit->meta.id, job_type_to_string(type));
1274
1275         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, override, &ret)) < 0) {
1276                 transaction_abort(m);
1277                 return r;
1278         }
1279
1280         if ((r = transaction_activate(m, mode)) < 0)
1281                 return r;
1282
1283         log_debug("Enqueued job %s/%s as %u", unit->meta.id, job_type_to_string(type), (unsigned) ret->id);
1284
1285         if (_ret)
1286                 *_ret = ret;
1287
1288         return 0;
1289 }
1290
1291 int manager_add_job_by_name(Manager *m, JobType type, const char *name, JobMode mode, bool override, Job **_ret) {
1292         Unit *unit;
1293         int r;
1294
1295         assert(m);
1296         assert(type < _JOB_TYPE_MAX);
1297         assert(name);
1298         assert(mode < _JOB_MODE_MAX);
1299
1300         if ((r = manager_load_unit(m, name, NULL, &unit)) < 0)
1301                 return r;
1302
1303         return manager_add_job(m, type, unit, mode, override, _ret);
1304 }
1305
1306 Job *manager_get_job(Manager *m, uint32_t id) {
1307         assert(m);
1308
1309         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
1310 }
1311
1312 Unit *manager_get_unit(Manager *m, const char *name) {
1313         assert(m);
1314         assert(name);
1315
1316         return hashmap_get(m->units, name);
1317 }
1318
1319 unsigned manager_dispatch_load_queue(Manager *m) {
1320         Meta *meta;
1321         unsigned n = 0;
1322
1323         assert(m);
1324
1325         /* Make sure we are not run recursively */
1326         if (m->dispatching_load_queue)
1327                 return 0;
1328
1329         m->dispatching_load_queue = true;
1330
1331         /* Dispatches the load queue. Takes a unit from the queue and
1332          * tries to load its data until the queue is empty */
1333
1334         while ((meta = m->load_queue)) {
1335                 assert(meta->in_load_queue);
1336
1337                 unit_load(UNIT(meta));
1338                 n++;
1339         }
1340
1341         m->dispatching_load_queue = false;
1342         return n;
1343 }
1344
1345 int manager_load_unit(Manager *m, const char *name, const char *path, Unit **_ret) {
1346         Unit *ret;
1347         int r;
1348
1349         assert(m);
1350         assert(name || path);
1351
1352         /* This will load the service information files, but not actually
1353          * start any services or anything. */
1354
1355         if (path && !is_path(path))
1356                 return -EINVAL;
1357
1358         if (!name)
1359                 name = file_name_from_path(path);
1360
1361         if (!unit_name_is_valid(name))
1362                 return -EINVAL;
1363
1364         if ((ret = manager_get_unit(m, name))) {
1365                 *_ret = ret;
1366                 return 0;
1367         }
1368
1369         if (!(ret = unit_new(m)))
1370                 return -ENOMEM;
1371
1372         if (path)
1373                 if (!(ret->meta.fragment_path = strdup(path))) {
1374                         unit_free(ret);
1375                         return -ENOMEM;
1376                 }
1377
1378         if ((r = unit_add_name(ret, name)) < 0) {
1379                 unit_free(ret);
1380                 return r;
1381         }
1382
1383         unit_add_to_load_queue(ret);
1384         unit_add_to_dbus_queue(ret);
1385
1386         manager_dispatch_load_queue(m);
1387
1388         if (_ret)
1389                 *_ret = unit_follow_merge(ret);
1390
1391         return 0;
1392 }
1393
1394 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
1395         Iterator i;
1396         Job *j;
1397
1398         assert(s);
1399         assert(f);
1400
1401         HASHMAP_FOREACH(j, s->jobs, i)
1402                 job_dump(j, f, prefix);
1403 }
1404
1405 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
1406         Iterator i;
1407         Unit *u;
1408         const char *t;
1409
1410         assert(s);
1411         assert(f);
1412
1413         HASHMAP_FOREACH_KEY(u, t, s->units, i)
1414                 if (u->meta.id == t)
1415                         unit_dump(u, f, prefix);
1416 }
1417
1418 void manager_clear_jobs(Manager *m) {
1419         Job *j;
1420
1421         assert(m);
1422
1423         transaction_abort(m);
1424
1425         while ((j = hashmap_first(m->jobs)))
1426                 job_free(j);
1427 }
1428
1429 unsigned manager_dispatch_run_queue(Manager *m) {
1430         Job *j;
1431         unsigned n = 0;
1432
1433         if (m->dispatching_run_queue)
1434                 return 0;
1435
1436         m->dispatching_run_queue = true;
1437
1438         while ((j = m->run_queue)) {
1439                 assert(j->installed);
1440                 assert(j->in_run_queue);
1441
1442                 job_run_and_invalidate(j);
1443                 n++;
1444         }
1445
1446         m->dispatching_run_queue = false;
1447         return n;
1448 }
1449
1450 unsigned manager_dispatch_dbus_queue(Manager *m) {
1451         Job *j;
1452         Meta *meta;
1453         unsigned n = 0;
1454
1455         assert(m);
1456
1457         if (m->dispatching_dbus_queue)
1458                 return 0;
1459
1460         m->dispatching_dbus_queue = true;
1461
1462         while ((meta = m->dbus_unit_queue)) {
1463                 assert(meta->in_dbus_queue);
1464
1465                 bus_unit_send_change_signal(UNIT(meta));
1466                 n++;
1467         }
1468
1469         while ((j = m->dbus_job_queue)) {
1470                 assert(j->in_dbus_queue);
1471
1472                 bus_job_send_change_signal(j);
1473                 n++;
1474         }
1475
1476         m->dispatching_dbus_queue = false;
1477         return n;
1478 }
1479
1480 static int manager_dispatch_sigchld(Manager *m) {
1481         assert(m);
1482
1483         for (;;) {
1484                 siginfo_t si;
1485                 Unit *u;
1486
1487                 zero(si);
1488
1489                 /* First we call waitd() for a PID and do not reap the
1490                  * zombie. That way we can still access /proc/$PID for
1491                  * it while it is a zombie. */
1492                 if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG|WNOWAIT) < 0) {
1493
1494                         if (errno == ECHILD)
1495                                 break;
1496
1497                         if (errno == EINTR)
1498                                 continue;
1499
1500                         return -errno;
1501                 }
1502
1503                 if (si.si_pid <= 0)
1504                         break;
1505
1506                 if (si.si_code == CLD_EXITED || si.si_code == CLD_KILLED || si.si_code == CLD_DUMPED) {
1507                         char *name = NULL;
1508
1509                         get_process_name(si.si_pid, &name);
1510                         log_debug("Got SIGCHLD for process %llu (%s)", (unsigned long long) si.si_pid, strna(name));
1511                         free(name);
1512                 }
1513
1514                 /* And now, we actually reap the zombie. */
1515                 if (waitid(P_PID, si.si_pid, &si, WEXITED) < 0) {
1516                         if (errno == EINTR)
1517                                 continue;
1518
1519                         return -errno;
1520                 }
1521
1522                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
1523                         continue;
1524
1525                 log_debug("Child %llu died (code=%s, status=%i/%s)",
1526                           (long long unsigned) si.si_pid,
1527                           sigchld_code_to_string(si.si_code),
1528                           si.si_status,
1529                           strna(si.si_code == CLD_EXITED ? exit_status_to_string(si.si_status) : strsignal(si.si_status)));
1530
1531                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
1532                         continue;
1533
1534                 log_debug("Child %llu belongs to %s", (long long unsigned) si.si_pid, u->meta.id);
1535
1536                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
1537         }
1538
1539         return 0;
1540 }
1541
1542 static void manager_start_target(Manager *m, const char *name) {
1543         int r;
1544
1545         if ((r = manager_add_job_by_name(m, JOB_START, name, JOB_REPLACE, true, NULL)) < 0)
1546                 log_error("Failed to enqueue %s job: %s", name, strerror(-r));
1547 }
1548
1549 static int manager_process_signal_fd(Manager *m, bool *quit) {
1550         ssize_t n;
1551         struct signalfd_siginfo sfsi;
1552         bool sigchld = false;
1553
1554         assert(m);
1555
1556         for (;;) {
1557                 if ((n = read(m->signal_watch.fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
1558
1559                         if (n >= 0)
1560                                 return -EIO;
1561
1562                         if (errno == EAGAIN)
1563                                 break;
1564
1565                         return -errno;
1566                 }
1567
1568                 switch (sfsi.ssi_signo) {
1569
1570                 case SIGCHLD:
1571                         sigchld = true;
1572                         break;
1573
1574                 case SIGINT:
1575                 case SIGTERM:
1576
1577                         if (m->running_as == MANAGER_INIT) {
1578                                 manager_start_target(m, SPECIAL_CTRL_ALT_DEL_TARGET);
1579                                 break;
1580                         }
1581
1582                         *quit = true;
1583                         return 0;
1584
1585                 case SIGWINCH:
1586
1587                         if (m->running_as == MANAGER_INIT)
1588                                 manager_start_target(m, SPECIAL_KBREQUEST_TARGET);
1589
1590                         /* This is a nop on non-init */
1591                         break;
1592
1593                 case SIGPWR:
1594                         if (m->running_as == MANAGER_INIT)
1595                                 manager_start_target(m, SPECIAL_SIGPWR_TARGET);
1596
1597                         /* This is a nop on non-init */
1598                         break;
1599
1600                 case SIGUSR1:
1601                         manager_dump_units(m, stdout, "\t");
1602                         manager_dump_jobs(m, stdout, "\t");
1603                         break;
1604
1605                 case SIGUSR2:  {
1606                         Unit *u;
1607
1608                         u = manager_get_unit(m, SPECIAL_DBUS_SERVICE);
1609
1610                         if (!u || UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(u))) {
1611                                 log_info("Trying to reconnect to bus...");
1612                                 bus_init_system(m);
1613                                 bus_init_api(m);
1614                         }
1615
1616                         if (!u || !UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u))) {
1617                                 log_info("Loading D-Bus service...");
1618                                 manager_start_target(m, SPECIAL_DBUS_SERVICE);
1619                         }
1620
1621                         break;
1622                 }
1623
1624                 default:
1625                         log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));
1626                 }
1627         }
1628
1629         if (sigchld)
1630                 return manager_dispatch_sigchld(m);
1631
1632         return 0;
1633 }
1634
1635 static int process_event(Manager *m, struct epoll_event *ev, bool *quit) {
1636         int r;
1637         Watch *w;
1638
1639         assert(m);
1640         assert(ev);
1641
1642         assert(w = ev->data.ptr);
1643
1644         switch (w->type) {
1645
1646         case WATCH_SIGNAL:
1647
1648                 /* An incoming signal? */
1649                 if (ev->events != EPOLLIN)
1650                         return -EINVAL;
1651
1652                 if ((r = manager_process_signal_fd(m, quit)) < 0)
1653                         return r;
1654
1655                 break;
1656
1657         case WATCH_FD:
1658
1659                 /* Some fd event, to be dispatched to the units */
1660                 UNIT_VTABLE(w->data.unit)->fd_event(w->data.unit, w->fd, ev->events, w);
1661                 break;
1662
1663         case WATCH_TIMER: {
1664                 uint64_t v;
1665                 ssize_t k;
1666
1667                 /* Some timer event, to be dispatched to the units */
1668                 if ((k = read(w->fd, &v, sizeof(v))) != sizeof(v)) {
1669
1670                         if (k < 0 && (errno == EINTR || errno == EAGAIN))
1671                                 break;
1672
1673                         return k < 0 ? -errno : -EIO;
1674                 }
1675
1676                 UNIT_VTABLE(w->data.unit)->timer_event(w->data.unit, v, w);
1677                 break;
1678         }
1679
1680         case WATCH_MOUNT:
1681                 /* Some mount table change, intended for the mount subsystem */
1682                 mount_fd_event(m, ev->events);
1683                 break;
1684
1685         case WATCH_UDEV:
1686                 /* Some notification from udev, intended for the device subsystem */
1687                 device_fd_event(m, ev->events);
1688                 break;
1689
1690         case WATCH_DBUS_WATCH:
1691                 bus_watch_event(m, w, ev->events);
1692                 break;
1693
1694         case WATCH_DBUS_TIMEOUT:
1695                 bus_timeout_event(m, w, ev->events);
1696                 break;
1697
1698         default:
1699                 assert_not_reached("Unknown epoll event type.");
1700         }
1701
1702         return 0;
1703 }
1704
1705 int manager_loop(Manager *m) {
1706         int r;
1707         bool quit = false;
1708
1709         RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 1000);
1710
1711         assert(m);
1712
1713         do {
1714                 struct epoll_event event;
1715                 int n;
1716
1717                 if (!ratelimit_test(&rl)) {
1718                         /* Yay, something is going seriously wrong, pause a little */
1719                         log_warning("Looping too fast. Throttling execution a little.");
1720                         sleep(1);
1721                 }
1722
1723                 if (manager_dispatch_cleanup_queue(m) > 0)
1724                         continue;
1725
1726                 if (manager_dispatch_load_queue(m) > 0)
1727                         continue;
1728
1729                 if (manager_dispatch_run_queue(m) > 0)
1730                         continue;
1731
1732                 if (bus_dispatch(m) > 0)
1733                         continue;
1734
1735                 if (manager_dispatch_dbus_queue(m) > 0)
1736                         continue;
1737
1738                 if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
1739
1740                         if (errno == -EINTR)
1741                                 continue;
1742
1743                         return -errno;
1744                 }
1745
1746                 assert(n == 1);
1747
1748                 if ((r = process_event(m, &event, &quit)) < 0)
1749                         return r;
1750         } while (!quit);
1751
1752         return 0;
1753 }
1754
1755 int manager_get_unit_from_dbus_path(Manager *m, const char *s, Unit **_u) {
1756         char *n;
1757         Unit *u;
1758
1759         assert(m);
1760         assert(s);
1761         assert(_u);
1762
1763         if (!startswith(s, "/org/freedesktop/systemd1/unit/"))
1764                 return -EINVAL;
1765
1766         if (!(n = bus_path_unescape(s+31)))
1767                 return -ENOMEM;
1768
1769         u = manager_get_unit(m, n);
1770         free(n);
1771
1772         if (!u)
1773                 return -ENOENT;
1774
1775         *_u = u;
1776
1777         return 0;
1778 }
1779
1780 int manager_get_job_from_dbus_path(Manager *m, const char *s, Job **_j) {
1781         Job *j;
1782         unsigned id;
1783         int r;
1784
1785         assert(m);
1786         assert(s);
1787         assert(_j);
1788
1789         if (!startswith(s, "/org/freedesktop/systemd1/job/"))
1790                 return -EINVAL;
1791
1792         if ((r = safe_atou(s + 30, &id)) < 0)
1793                 return r;
1794
1795         if (!(j = manager_get_job(m, id)))
1796                 return -ENOENT;
1797
1798         *_j = j;
1799
1800         return 0;
1801 }
1802
1803 static bool manager_utmp_good(Manager *m) {
1804         int r;
1805
1806         assert(m);
1807
1808         if ((r = mount_path_is_mounted(m, _PATH_UTMPX)) <= 0) {
1809
1810                 if (r < 0)
1811                         log_warning("Failed to determine whether " _PATH_UTMPX " is mounted: %s", strerror(-r));
1812
1813                 return false;
1814         }
1815
1816         return true;
1817 }
1818
1819 void manager_write_utmp_reboot(Manager *m) {
1820         int r;
1821
1822         assert(m);
1823
1824         if (m->utmp_reboot_written)
1825                 return;
1826
1827         if (m->running_as != MANAGER_INIT)
1828                 return;
1829
1830         if (!manager_utmp_good(m))
1831                 return;
1832
1833         if ((r = utmp_put_reboot(m->boot_timestamp)) < 0) {
1834
1835                 if (r != -ENOENT && r != -EROFS)
1836                         log_warning("Failed to write utmp/wtmp: %s", strerror(-r));
1837
1838                 return;
1839         }
1840
1841         m->utmp_reboot_written = true;
1842 }
1843
1844 void manager_write_utmp_runlevel(Manager *m, Unit *u) {
1845         int runlevel, r;
1846
1847         assert(m);
1848         assert(u);
1849
1850         if (u->meta.type != UNIT_TARGET)
1851                 return;
1852
1853         if (m->running_as != MANAGER_INIT)
1854                 return;
1855
1856         if (!manager_utmp_good(m))
1857                 return;
1858
1859         if ((runlevel = target_get_runlevel(TARGET(u))) <= 0)
1860                 return;
1861
1862         if ((r = utmp_put_runlevel(0, runlevel, 0)) < 0) {
1863
1864                 if (r != -ENOENT && r != -EROFS)
1865                         log_warning("Failed to write utmp/wtmp: %s", strerror(-r));
1866         }
1867 }
1868
1869 static const char* const manager_running_as_table[_MANAGER_RUNNING_AS_MAX] = {
1870         [MANAGER_INIT] = "init",
1871         [MANAGER_SYSTEM] = "system",
1872         [MANAGER_SESSION] = "session"
1873 };
1874
1875 DEFINE_STRING_TABLE_LOOKUP(manager_running_as, ManagerRunningAs);