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