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