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