manager.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <assert.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <sys/epoll.h>
   7 #include <signal.h>
   8 #include <sys/signalfd.h>
   9 #include <sys/wait.h>
  10 #include <unistd.h>
  11 #include <sys/poll.h>
  12
  13 #include "manager.h"
  14 #include "hashmap.h"
  15 #include "macro.h"
  16 #include "strv.h"
  17 #include "log.h"
  18 #include "util.h"
  19
  20 static const char * const special_table[_SPECIAL_UNIT_MAX] = {
  21         [SPECIAL_SYSLOG_SERVICE] = "syslog.service",
  22         [SPECIAL_DBUS_SERVICE] = "messagebus.service",
  23         [SPECIAL_LOGGER_SOCKET] = "systemd-logger.socket"
  24 };
  25
  26 static int manager_setup_signals(Manager *m) {
  27         sigset_t mask;
  28         struct epoll_event ev;
  29
  30         assert(m);
  31
  32         assert_se(reset_all_signal_handlers() == 0);
  33
  34         assert_se(sigemptyset(&mask) == 0);
  35         assert_se(sigaddset(&mask, SIGCHLD) == 0);
  36         assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
  37         assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
  38         assert_se(sigaddset(&mask, SIGTERM) == 0);
  39         assert_se(sigaddset(&mask, SIGHUP) == 0);
  40         assert_se(sigaddset(&mask, SIGUSR1) == 0);
  41         assert_se(sigaddset(&mask, SIGUSR2) == 0);
  42         assert_se(sigaddset(&mask, SIGPIPE) == 0);
  43         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
  44
  45         m->signal_watch.type = WATCH_SIGNAL_FD;
  46         if ((m->signal_watch.fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
  47                 return -errno;
  48
  49         zero(ev);
  50         ev.events = EPOLLIN;
  51         ev.data.ptr = &m->signal_watch;
  52
  53         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
  54                 return -errno;
  55
  56         return 0;
  57 }
  58
  59 static int manager_load_special_units(Manager *m) {
  60         SpecialUnit c;
  61         int r;
  62
  63         assert(m);
  64
  65         /* Loads all 'special' units, so that we have easy access to them later */
  66
  67         for (c = 0; c < _SPECIAL_UNIT_MAX; c++)
  68                 if ((r = manager_load_unit(m, special_table[c], m->special_units+c)) < 0)
  69                         return r;
  70
  71         return 0;
  72 };
  73
  74 Manager* manager_new(void) {
  75         Manager *m;
  76
  77         if (!(m = new0(Manager, 1)))
  78                 return NULL;
  79
  80         m->signal_watch.fd = m->epoll_fd = -1;
  81
  82         if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
  83                 goto fail;
  84
  85         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  86                 goto fail;
  87
  88         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  89                 goto fail;
  90
  91         if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
  92                 goto fail;
  93
  94         if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
  95                 goto fail;
  96
  97         if (manager_setup_signals(m) < 0)
  98                 goto fail;
  99
 100         if (manager_load_special_units(m) < 0)
 101                 goto fail;
 102
 103         return m;
 104
 105 fail:
 106         manager_free(m);
 107         return NULL;
 108 }
 109
 110 void manager_free(Manager *m) {
 111         Unit *u;
 112         Job *j;
 113
 114         assert(m);
 115
 116         while ((j = hashmap_first(m->transaction_jobs)))
 117                 job_free(j);
 118
 119         while ((u = hashmap_first(m->units)))
 120                 unit_free(u);
 121
 122         hashmap_free(m->units);
 123         hashmap_free(m->jobs);
 124         hashmap_free(m->transaction_jobs);
 125         hashmap_free(m->watch_pids);
 126
 127         if (m->epoll_fd >= 0)
 128                 close_nointr(m->epoll_fd);
 129         if (m->signal_watch.fd >= 0)
 130                 close_nointr(m->signal_watch.fd);
 131
 132         free(m);
 133 }
 134
 135 static void transaction_delete_job(Manager *m, Job *j) {
 136         assert(m);
 137         assert(j);
 138
 139         /* Deletes one job from the transaction */
 140
 141         manager_transaction_unlink_job(m, j);
 142
 143         if (!j->installed)
 144                 job_free(j);
 145 }
 146
 147 static void transaction_delete_unit(Manager *m, Unit *u) {
 148         Job *j;
 149
 150         /* Deletes all jobs associated with a certain unit from the
 151          * transaction */
 152
 153         while ((j = hashmap_get(m->transaction_jobs, u)))
 154                 transaction_delete_job(m, j);
 155 }
 156
 157 static void transaction_clean_dependencies(Manager *m) {
 158         Iterator i;
 159         Job *j;
 160
 161         assert(m);
 162
 163         /* Drops all dependencies of all installed jobs */
 164
 165         HASHMAP_FOREACH(j, m->jobs, i) {
 166                 while (j->subject_list)
 167                         job_dependency_free(j->subject_list);
 168                 while (j->object_list)
 169                         job_dependency_free(j->object_list);
 170         }
 171
 172         assert(!m->transaction_anchor);
 173 }
 174
 175 static void transaction_abort(Manager *m) {
 176         Job *j;
 177
 178         assert(m);
 179
 180         while ((j = hashmap_first(m->transaction_jobs)))
 181                 if (j->installed)
 182                         transaction_delete_job(m, j);
 183                 else
 184                         job_free(j);
 185
 186         assert(hashmap_isempty(m->transaction_jobs));
 187
 188         transaction_clean_dependencies(m);
 189 }
 190
 191 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
 192         JobDependency *l;
 193
 194         assert(m);
 195
 196         /* A recursive sweep through the graph that marks all units
 197          * that matter to the anchor job, i.e. are directly or
 198          * indirectly a dependency of the anchor job via paths that
 199          * are fully marked as mattering. */
 200
 201         if (j)
 202                 l = j->subject_list;
 203         else
 204                 l = m->transaction_anchor;
 205
 206         LIST_FOREACH(subject, l, l) {
 207
 208                 /* This link does not matter */
 209                 if (!l->matters)
 210                         continue;
 211
 212                 /* This unit has already been marked */
 213                 if (l->object->generation == generation)
 214                         continue;
 215
 216                 l->object->matters_to_anchor = true;
 217                 l->object->generation = generation;
 218
 219                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
 220         }
 221 }
 222
 223 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 224         JobDependency *l, *last;
 225
 226         assert(j);
 227         assert(other);
 228         assert(j->unit == other->unit);
 229         assert(!j->installed);
 230
 231         /* Merges 'other' into 'j' and then deletes j. */
 232
 233         j->type = t;
 234         j->state = JOB_WAITING;
 235         j->forced = j->forced || other->forced;
 236
 237         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 238
 239         /* Patch us in as new owner of the JobDependency objects */
 240         last = NULL;
 241         LIST_FOREACH(subject, l, other->subject_list) {
 242                 assert(l->subject == other);
 243                 l->subject = j;
 244                 last = l;
 245         }
 246
 247         /* Merge both lists */
 248         if (last) {
 249                 last->subject_next = j->subject_list;
 250                 if (j->subject_list)
 251                         j->subject_list->subject_prev = last;
 252                 j->subject_list = other->subject_list;
 253         }
 254
 255         /* Patch us in as new owner of the JobDependency objects */
 256         last = NULL;
 257         LIST_FOREACH(object, l, other->object_list) {
 258                 assert(l->object == other);
 259                 l->object = j;
 260                 last = l;
 261         }
 262
 263         /* Merge both lists */
 264         if (last) {
 265                 last->object_next = j->object_list;
 266                 if (j->object_list)
 267                         j->object_list->object_prev = last;
 268                 j->object_list = other->object_list;
 269         }
 270
 271         /* Kill the other job */
 272         other->subject_list = NULL;
 273         other->object_list = NULL;
 274         transaction_delete_job(m, other);
 275 }
 276
 277 static int delete_one_unmergeable_job(Manager *m, Job *j) {
 278         Job *k;
 279
 280         assert(j);
 281
 282         /* Tries to delete one item in the linked list
 283          * j->transaction_next->transaction_next->... that conflicts
 284          * whith another one, in an attempt to make an inconsistent
 285          * transaction work. */
 286
 287         /* We rely here on the fact that if a merged with b does not
 288          * merge with c, either a or b merge with c neither */
 289         LIST_FOREACH(transaction, j, j)
 290                 LIST_FOREACH(transaction, k, j->transaction_next) {
 291                         Job *d;
 292
 293                         /* Is this one mergeable? Then skip it */
 294                         if (job_type_is_mergeable(j->type, k->type))
 295                                 continue;
 296
 297                         /* Ok, we found two that conflict, let's see if we can
 298                          * drop one of them */
 299                         if (!j->matters_to_anchor)
 300                                 d = j;
 301                         else if (!k->matters_to_anchor)
 302                                 d = k;
 303                         else
 304                                 return -ENOEXEC;
 305
 306                         /* Ok, we can drop one, so let's do so. */
 307                         log_debug("Try to fix job merging by deleting job %s/%s", unit_id(d->unit), job_type_to_string(d->type));
 308                         transaction_delete_job(m, d);
 309                         return 0;
 310                 }
 311
 312         return -EINVAL;
 313 }
 314
 315 static int transaction_merge_jobs(Manager *m) {
 316         Job *j;
 317         Iterator i;
 318         int r;
 319
 320         assert(m);
 321
 322         /* First step, check whether any of the jobs for one specific
 323          * task conflict. If so, try to drop one of them. */
 324         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 325                 JobType t;
 326                 Job *k;
 327
 328                 t = j->type;
 329                 LIST_FOREACH(transaction, k, j->transaction_next) {
 330                         if ((r = job_type_merge(&t, k->type)) >= 0)
 331                                 continue;
 332
 333                         /* OK, we could not merge all jobs for this
 334                          * action. Let's see if we can get rid of one
 335                          * of them */
 336
 337                         if ((r = delete_one_unmergeable_job(m, j)) >= 0)
 338                                 /* Ok, we managed to drop one, now
 339                                  * let's ask our callers to call us
 340                                  * again after garbage collecting */
 341                                 return -EAGAIN;
 342
 343                         /* We couldn't merge anything. Failure */
 344                         return r;
 345                 }
 346         }
 347
 348         /* Second step, merge the jobs. */
 349         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 350                 JobType t = j->type;
 351                 Job *k;
 352
 353                 /* Merge all transactions */
 354                 LIST_FOREACH(transaction, k, j->transaction_next)
 355                         assert_se(job_type_merge(&t, k->type) == 0);
 356
 357                 /* If an active job is mergeable, merge it too */
 358                 if (j->unit->meta.job)
 359                         job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
 360
 361                 while ((k = j->transaction_next)) {
 362                         if (j->installed) {
 363                                 transaction_merge_and_delete_job(m, k, j, t);
 364                                 j = k;
 365                         } else
 366                                 transaction_merge_and_delete_job(m, j, k, t);
 367                 }
 368
 369                 assert(!j->transaction_next);
 370                 assert(!j->transaction_prev);
 371         }
 372
 373         return 0;
 374 }
 375
 376 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 377         assert(u);
 378         assert(!j->transaction_prev);
 379
 380         /* Checks whether at least one of the jobs for this unit
 381          * matters to the anchor. */
 382
 383         LIST_FOREACH(transaction, j, j)
 384                 if (j->matters_to_anchor)
 385                         return true;
 386
 387         return false;
 388 }
 389
 390 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 391         Iterator i;
 392         Unit *u;
 393         int r;
 394
 395         assert(m);
 396         assert(j);
 397         assert(!j->transaction_prev);
 398
 399         /* Does a recursive sweep through the ordering graph, looking
 400          * for a cycle. If we find cycle we try to break it. */
 401
 402         /* Did we find a cycle? */
 403         if (j->marker && j->generation == generation) {
 404                 Job *k;
 405
 406                 /* So, we already have been here. We have a
 407                  * cycle. Let's try to break it. We go backwards in
 408                  * our path and try to find a suitable job to
 409                  * remove. We use the marker to find our way back,
 410                  * since smart how we are we stored our way back in
 411                  * there. */
 412
 413                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 414
 415                         if (!k->installed &&
 416                             !unit_matters_to_anchor(k->unit, k)) {
 417                                 /* Ok, we can drop this one, so let's
 418                                  * do so. */
 419                                 log_debug("Breaking order cycle by deleting job %s/%s", unit_id(k->unit), job_type_to_string(k->type));
 420                                 transaction_delete_unit(m, k->unit);
 421                                 return -EAGAIN;
 422                         }
 423
 424                         /* Check if this in fact was the beginning of
 425                          * the cycle */
 426                         if (k == j)
 427                                 break;
 428                 }
 429
 430                 return -ENOEXEC;
 431         }
 432
 433         /* Make the marker point to where we come from, so that we can
 434          * find our way backwards if we want to break a cycle */
 435         j->marker = from;
 436         j->generation = generation;
 437
 438         /* We assume that the the dependencies are bidirectional, and
 439          * hence can ignore UNIT_AFTER */
 440         SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
 441                 Job *o;
 442
 443                 /* Is there a job for this unit? */
 444                 if (!(o = hashmap_get(m->transaction_jobs, u)))
 445
 446                         /* Ok, there is no job for this in the
 447                          * transaction, but maybe there is already one
 448                          * running? */
 449                         if (!(o = u->meta.job))
 450                                 continue;
 451
 452                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 453                         return r;
 454         }
 455
 456         return 0;
 457 }
 458
 459 static int transaction_verify_order(Manager *m, unsigned *generation) {
 460         Job *j;
 461         int r;
 462         Iterator i;
 463
 464         assert(m);
 465         assert(generation);
 466
 467         /* Check if the ordering graph is cyclic. If it is, try to fix
 468          * that up by dropping one of the jobs. */
 469
 470         HASHMAP_FOREACH(j, m->transaction_jobs, i)
 471                 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
 472                         return r;
 473
 474         return 0;
 475 }
 476
 477 static void transaction_collect_garbage(Manager *m) {
 478         bool again;
 479
 480         assert(m);
 481
 482         /* Drop jobs that are not required by any other job */
 483
 484         do {
 485                 Iterator i;
 486                 Job *j;
 487
 488                 again = false;
 489
 490                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 491                         if (j->object_list)
 492                                 continue;
 493
 494                         log_debug("Garbage collecting job %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 495                         transaction_delete_job(m, j);
 496                         again = true;
 497                         break;
 498                 }
 499
 500         } while (again);
 501 }
 502
 503 static int transaction_is_destructive(Manager *m, JobMode mode) {
 504         Iterator i;
 505         Job *j;
 506
 507         assert(m);
 508
 509         /* Checks whether applying this transaction means that
 510          * existing jobs would be replaced */
 511
 512         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 513
 514                 /* Assume merged */
 515                 assert(!j->transaction_prev);
 516                 assert(!j->transaction_next);
 517
 518                 if (j->unit->meta.job &&
 519                     j->unit->meta.job != j &&
 520                     !job_type_is_superset(j->type, j->unit->meta.job->type))
 521                         return -EEXIST;
 522         }
 523
 524         return 0;
 525 }
 526
 527 static void transaction_minimize_impact(Manager *m) {
 528         bool again;
 529         assert(m);
 530
 531         /* Drops all unnecessary jobs that reverse already active jobs
 532          * or that stop a running service. */
 533
 534         do {
 535                 Job *j;
 536                 Iterator i;
 537
 538                 again = false;
 539
 540                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 541                         LIST_FOREACH(transaction, j, j) {
 542
 543                                 /* If it matters, we shouldn't drop it */
 544                                 if (j->matters_to_anchor)
 545                                         continue;
 546
 547                                 /* Would this stop a running service?
 548                                  * Would this change an existing job?
 549                                  * If so, let's drop this entry */
 550                                 if ((j->type != JOB_STOP || UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(j->unit))) &&
 551                                     (!j->unit->meta.job  || job_type_is_conflicting(j->type, j->unit->meta.job->state)))
 552                                         continue;
 553
 554                                 /* Ok, let's get rid of this */
 555                                 log_debug("Deleting %s/%s to minimize impact", unit_id(j->unit), job_type_to_string(j->type));
 556                                 transaction_delete_job(m, j);
 557                                 again = true;
 558                                 break;
 559                         }
 560
 561                         if (again)
 562                                 break;
 563                 }
 564
 565         } while (again);
 566 }
 567
 568 static int transaction_apply(Manager *m, JobMode mode) {
 569         Iterator i;
 570         Job *j;
 571         int r;
 572
 573         /* Moves the transaction jobs to the set of active jobs */
 574
 575         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 576                 /* Assume merged */
 577                 assert(!j->transaction_prev);
 578                 assert(!j->transaction_next);
 579
 580                 if (j->installed)
 581                         continue;
 582
 583                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 584                         goto rollback;
 585         }
 586
 587         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 588                 if (j->installed)
 589                         continue;
 590
 591                 if (j->unit->meta.job)
 592                         job_free(j->unit->meta.job);
 593
 594                 j->unit->meta.job = j;
 595                 j->installed = true;
 596
 597                 /* We're fully installed. Now let's free data we don't
 598                  * need anymore. */
 599
 600                 assert(!j->transaction_next);
 601                 assert(!j->transaction_prev);
 602
 603                 job_schedule_run(j);
 604         }
 605
 606         /* As last step, kill all remaining job dependencies. */
 607         transaction_clean_dependencies(m);
 608
 609         return 0;
 610
 611 rollback:
 612
 613         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 614                 if (j->installed)
 615                         continue;
 616
 617                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 618         }
 619
 620         return r;
 621 }
 622
 623 static int transaction_activate(Manager *m, JobMode mode) {
 624         int r;
 625         unsigned generation = 1;
 626
 627         assert(m);
 628
 629         /* This applies the changes recorded in transaction_jobs to
 630          * the actual list of jobs, if possible. */
 631
 632         /* First step: figure out which jobs matter */
 633         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 634
 635         /* Second step: Try not to stop any running services if
 636          * we don't have to. Don't try to reverse running
 637          * jobs if we don't have to. */
 638         transaction_minimize_impact(m);
 639
 640         for (;;) {
 641                 /* Third step: Let's remove unneeded jobs that might
 642                  * be lurking. */
 643                 transaction_collect_garbage(m);
 644
 645                 /* Fourth step: verify order makes sense and correct
 646                  * cycles if necessary and possible */
 647                 if ((r = transaction_verify_order(m, &generation)) >= 0)
 648                         break;
 649
 650                 if (r != -EAGAIN)
 651                         goto rollback;
 652
 653                 /* Let's see if the resulting transaction ordering
 654                  * graph is still cyclic... */
 655         }
 656
 657         for (;;) {
 658                 /* Fifth step: let's drop unmergeable entries if
 659                  * necessary and possible, merge entries we can
 660                  * merge */
 661                 if ((r = transaction_merge_jobs(m)) >= 0)
 662                         break;
 663
 664                 if (r != -EAGAIN)
 665                         goto rollback;
 666
 667                 /* Sixth step: an entry got dropped, let's garbage
 668                  * collect its dependencies. */
 669                 transaction_collect_garbage(m);
 670
 671                 /* Let's see if the resulting transaction still has
 672                  * unmergeable entries ... */
 673         }
 674
 675         /* Seventh step: check whether we can actually apply this */
 676         if (mode == JOB_FAIL)
 677                 if ((r = transaction_is_destructive(m, mode)) < 0)
 678                         goto rollback;
 679
 680         /* Eights step: apply changes */
 681         if ((r = transaction_apply(m, mode)) < 0)
 682                 goto rollback;
 683
 684         assert(hashmap_isempty(m->transaction_jobs));
 685         assert(!m->transaction_anchor);
 686
 687         return 0;
 688
 689 rollback:
 690         transaction_abort(m);
 691         return r;
 692 }
 693
 694 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool force, bool *is_new) {
 695         Job *j, *f;
 696         int r;
 697
 698         assert(m);
 699         assert(unit);
 700
 701         /* Looks for an axisting prospective job and returns that. If
 702          * it doesn't exist it is created and added to the prospective
 703          * jobs list. */
 704
 705         f = hashmap_get(m->transaction_jobs, unit);
 706
 707         LIST_FOREACH(transaction, j, f) {
 708                 assert(j->unit == unit);
 709
 710                 if (j->type == type) {
 711                         if (is_new)
 712                                 *is_new = false;
 713                         return j;
 714                 }
 715         }
 716
 717         if (unit->meta.job && unit->meta.job->type == type)
 718                 j = unit->meta.job;
 719         else if (!(j = job_new(m, type, unit)))
 720                 return NULL;
 721
 722         j->generation = 0;
 723         j->marker = NULL;
 724         j->matters_to_anchor = false;
 725         j->forced = force;
 726
 727         LIST_PREPEND(Job, transaction, f, j);
 728
 729         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
 730                 job_free(j);
 731                 return NULL;
 732         }
 733
 734         if (is_new)
 735                 *is_new = true;
 736
 737         return j;
 738 }
 739
 740 void manager_transaction_unlink_job(Manager *m, Job *j) {
 741         assert(m);
 742         assert(j);
 743
 744         if (j->transaction_prev)
 745                 j->transaction_prev->transaction_next = j->transaction_next;
 746         else if (j->transaction_next)
 747                 hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
 748         else
 749                 hashmap_remove_value(m->transaction_jobs, j->unit, j);
 750
 751         if (j->transaction_next)
 752                 j->transaction_next->transaction_prev = j->transaction_prev;
 753
 754         j->transaction_prev = j->transaction_next = NULL;
 755
 756         while (j->subject_list)
 757                 job_dependency_free(j->subject_list);
 758
 759         while (j->object_list) {
 760                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 761
 762                 job_dependency_free(j->object_list);
 763
 764                 if (other) {
 765                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
 766                                   unit_id(other->unit), job_type_to_string(other->type),
 767                                   unit_id(j->unit), job_type_to_string(j->type));
 768                         transaction_delete_job(m, other);
 769                 }
 770         }
 771 }
 772
 773 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Unit *unit, Job *by, bool matters, bool force, Job **_ret) {
 774         Job *ret;
 775         Iterator i;
 776         Unit *dep;
 777         int r;
 778         bool is_new;
 779
 780         assert(m);
 781         assert(type < _JOB_TYPE_MAX);
 782         assert(unit);
 783
 784         if (unit->meta.load_state != UNIT_LOADED)
 785                 return -EINVAL;
 786
 787         if (!unit_job_is_applicable(unit, type))
 788                 return -EBADR;
 789
 790         /* First add the job. */
 791         if (!(ret = transaction_add_one_job(m, type, unit, force, &is_new)))
 792                 return -ENOMEM;
 793
 794         /* Then, add a link to the job. */
 795         if (!job_dependency_new(by, ret, matters))
 796                 return -ENOMEM;
 797
 798         if (is_new) {
 799                 /* Finally, recursively add in all dependencies. */
 800                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 801                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
 802                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 803                                         goto fail;
 804                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 805                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 806                                         goto fail;
 807                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
 808                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR)
 809                                         goto fail;
 810                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
 811                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 812                                         goto fail;
 813                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUISITE], i)
 814                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 815                                         goto fail;
 816                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
 817                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 818                                         goto fail;
 819
 820                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 821
 822                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
 823                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 824                                         goto fail;
 825                 }
 826
 827                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 828         }
 829
 830         return 0;
 831
 832 fail:
 833         return r;
 834 }
 835
 836 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool force, Job **_ret) {
 837         int r;
 838         Job *ret;
 839
 840         assert(m);
 841         assert(type < _JOB_TYPE_MAX);
 842         assert(unit);
 843         assert(mode < _JOB_MODE_MAX);
 844
 845         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, force, &ret))) {
 846                 transaction_abort(m);
 847                 return r;
 848         }
 849
 850         if ((r = transaction_activate(m, mode)) < 0)
 851                 return r;
 852
 853         if (_ret)
 854                 *_ret = ret;
 855
 856         return 0;
 857 }
 858
 859 Job *manager_get_job(Manager *m, uint32_t id) {
 860         assert(m);
 861
 862         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 863 }
 864
 865 Unit *manager_get_unit(Manager *m, const char *name) {
 866         assert(m);
 867         assert(name);
 868
 869         return hashmap_get(m->units, name);
 870 }
 871
 872 static void dispatch_load_queue(Manager *m) {
 873         Meta *meta;
 874
 875         assert(m);
 876
 877         /* Make sure we are not run recursively */
 878         if (m->dispatching_load_queue)
 879                 return;
 880
 881         m->dispatching_load_queue = true;
 882
 883         /* Dispatches the load queue. Takes a unit from the queue and
 884          * tries to load its data until the queue is empty */
 885
 886         while ((meta = m->load_queue)) {
 887                 assert(meta->in_load_queue);
 888
 889                 unit_load(UNIT(meta));
 890         }
 891
 892         m->dispatching_load_queue = false;
 893 }
 894
 895 int manager_load_unit(Manager *m, const char *path, Unit **_ret) {
 896         Unit *ret;
 897         int r;
 898         const char *name;
 899
 900         assert(m);
 901         assert(path);
 902         assert(_ret);
 903
 904         /* This will load the service information files, but not actually
 905          * start any services or anything. */
 906
 907         name = file_name_from_path(path);
 908
 909         if ((ret = manager_get_unit(m, name))) {
 910                 *_ret = ret;
 911                 return 0;
 912         }
 913
 914         if (!(ret = unit_new(m)))
 915                 return -ENOMEM;
 916
 917         if (is_path(path)) {
 918                 if (!(ret->meta.load_path = strdup(path))) {
 919                         unit_free(ret);
 920                         return -ENOMEM;
 921                 }
 922         }
 923
 924         if ((r = unit_add_name(ret, name)) < 0) {
 925                 unit_free(ret);
 926                 return r;
 927         }
 928
 929         unit_add_to_load_queue(ret);
 930         dispatch_load_queue(m);
 931
 932         *_ret = ret;
 933         return 0;
 934 }
 935
 936 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
 937         Iterator i;
 938         Job *j;
 939
 940         assert(s);
 941         assert(f);
 942
 943         HASHMAP_FOREACH(j, s->jobs, i)
 944                 job_dump(j, f, prefix);
 945 }
 946
 947 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
 948         Iterator i;
 949         Unit *u;
 950         const char *t;
 951
 952         assert(s);
 953         assert(f);
 954
 955         HASHMAP_FOREACH_KEY(u, t, s->units, i)
 956                 if (unit_id(u) == t)
 957                         unit_dump(u, f, prefix);
 958 }
 959
 960 void manager_clear_jobs(Manager *m) {
 961         Job *j;
 962
 963         assert(m);
 964
 965         transaction_abort(m);
 966
 967         while ((j = hashmap_first(m->jobs)))
 968                 job_free(j);
 969 }
 970
 971 void manager_dispatch_run_queue(Manager *m) {
 972         Job *j;
 973
 974         if (m->dispatching_run_queue)
 975                 return;
 976
 977         m->dispatching_run_queue = true;
 978
 979         while ((j = m->run_queue)) {
 980                 assert(j->installed);
 981                 assert(j->in_run_queue);
 982
 983                 job_run_and_invalidate(j);
 984         }
 985
 986         m->dispatching_run_queue = false;
 987 }
 988
 989 static int manager_dispatch_sigchld(Manager *m) {
 990         assert(m);
 991
 992         log_debug("dispatching SIGCHLD");
 993
 994         for (;;) {
 995                 siginfo_t si;
 996                 Unit *u;
 997
 998                 zero(si);
 999                 if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG) < 0) {
1000
1001                         if (errno == ECHILD)
1002                                 break;
1003
1004                         return -errno;
1005                 }
1006
1007                 if (si.si_pid == 0)
1008                         break;
1009
1010                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
1011                         continue;
1012
1013                 log_debug("child %llu died (code=%s, status=%i)", (long long unsigned) si.si_pid, sigchld_code(si.si_code), si.si_status);
1014
1015                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
1016                         continue;
1017
1018                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
1019         }
1020
1021         return 0;
1022 }
1023
1024 static int manager_process_signal_fd(Manager *m, bool *quit) {
1025         ssize_t n;
1026         struct signalfd_siginfo sfsi;
1027         bool sigchld = false;
1028
1029         assert(m);
1030
1031         for (;;) {
1032                 if ((n = read(m->signal_watch.fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
1033
1034                         if (n >= 0)
1035                                 return -EIO;
1036
1037                         if (errno == EAGAIN)
1038                                 break;
1039
1040                         return -errno;
1041                 }
1042
1043                 switch (sfsi.ssi_signo) {
1044
1045                 case SIGCHLD:
1046                         sigchld = true;
1047                         break;
1048
1049                 case SIGINT:
1050                 case SIGTERM:
1051                         *quit = true;
1052                         return 0;
1053
1054                 default:
1055                         log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));
1056                 }
1057         }
1058
1059         if (sigchld)
1060                 return manager_dispatch_sigchld(m);
1061
1062         return 0;
1063 }
1064
1065 static int process_event(Manager *m, struct epoll_event *ev, bool *quit) {
1066         int r;
1067         Watch *w;
1068
1069         assert(m);
1070         assert(ev);
1071
1072         assert(w = ev->data.ptr);
1073
1074         switch (w->type) {
1075
1076         case WATCH_SIGNAL_FD:
1077
1078                 /* An incoming signal? */
1079                 if (ev->events != POLLIN)
1080                         return -EINVAL;
1081
1082                 if ((r = manager_process_signal_fd(m, quit)) < 0)
1083                         return r;
1084
1085                 break;
1086
1087         case WATCH_FD:
1088
1089                 /* Some fd event, to be dispatched to the units */
1090                 UNIT_VTABLE(w->unit)->fd_event(w->unit, w->fd, ev->events, w);
1091                 break;
1092
1093         case WATCH_TIMER: {
1094                 uint64_t v;
1095                 ssize_t k;
1096
1097                 /* Some timer event, to be dispatched to the units */
1098                 if ((k = read(ev->data.fd, &v, sizeof(v))) != sizeof(v)) {
1099
1100                         if (k < 0 && (errno == EINTR || errno == EAGAIN))
1101                                 break;
1102
1103                         return k < 0 ? -errno : -EIO;
1104                 }
1105
1106                 UNIT_VTABLE(w->unit)->timer_event(w->unit, v, w);
1107                 break;
1108         }
1109
1110         default:
1111                 assert_not_reached("Unknown epoll event type.");
1112         }
1113
1114         return 0;
1115 }
1116
1117 int manager_loop(Manager *m) {
1118         int r;
1119         bool quit = false;
1120
1121         assert(m);
1122
1123         for (;;) {
1124                 struct epoll_event event;
1125                 int n;
1126
1127                 manager_dispatch_run_queue(m);
1128
1129                 if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
1130
1131                         if (errno == -EINTR)
1132                                 continue;
1133
1134                         return -errno;
1135                 }
1136
1137                 assert(n == 1);
1138
1139                 if ((r = process_event(m, &event, &quit)) < 0)
1140                         return r;
1141
1142                 if (quit)
1143                         return 0;
1144         }
1145 }