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_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(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
  47
  48         if ((m->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
  49                 goto fail;
  50
  51         zero(ev);
  52         ev.events = EPOLLIN;
  53         ev.data.fd = m->signal_fd;
  54
  55         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_fd, &ev) < 0)
  56                 goto fail;
  57
  58         return m;
  59
  60 fail:
  61         manager_free(m);
  62         return NULL;
  63 }
  64
  65 void manager_free(Manager *m) {
  66         Unit *u;
  67         Job *j;
  68
  69         assert(m);
  70
  71         while ((j = hashmap_first(m->transaction_jobs)))
  72                 job_free(j);
  73
  74         while ((u = hashmap_first(m->units)))
  75                 unit_free(u);
  76
  77         hashmap_free(m->units);
  78         hashmap_free(m->jobs);
  79         hashmap_free(m->transaction_jobs);
  80         hashmap_free(m->watch_pids);
  81
  82         if (m->epoll_fd >= 0)
  83                 close_nointr(m->epoll_fd);
  84         if (m->signal_fd >= 0)
  85                 close_nointr(m->signal_fd);
  86
  87         free(m);
  88 }
  89
  90 static void transaction_delete_job(Manager *m, Job *j) {
  91         assert(m);
  92         assert(j);
  93
  94         /* Deletes one job from the transaction */
  95
  96         manager_transaction_unlink_job(m, j);
  97
  98         if (!j->installed)
  99                 job_free(j);
 100 }
 101
 102 static void transaction_delete_unit(Manager *m, Unit *u) {
 103         Job *j;
 104
 105         /* Deletes all jobs associated with a certain unit from the
 106          * transaction */
 107
 108         while ((j = hashmap_get(m->transaction_jobs, u)))
 109                 transaction_delete_job(m, j);
 110 }
 111
 112 static void transaction_abort(Manager *m) {
 113         Job *j;
 114
 115         assert(m);
 116
 117         while ((j = hashmap_first(m->transaction_jobs)))
 118                 if (j->installed)
 119                         transaction_delete_job(m, j);
 120                 else
 121                         job_free(j);
 122
 123         assert(hashmap_isempty(m->transaction_jobs));
 124         assert(!m->transaction_anchor);
 125 }
 126
 127 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
 128         JobDependency *l;
 129
 130         assert(m);
 131
 132         /* A recursive sweep through the graph that marks all units
 133          * that matter to the anchor job, i.e. are directly or
 134          * indirectly a dependency of the anchor job via paths that
 135          * are fully marked as mattering. */
 136
 137         if (j)
 138                 l = j->subject_list;
 139         else
 140                 l = m->transaction_anchor;
 141
 142         LIST_FOREACH(subject, l, l) {
 143
 144                 /* This link does not matter */
 145                 if (!l->matters)
 146                         continue;
 147
 148                 /* This unit has already been marked */
 149                 if (l->object->generation == generation)
 150                         continue;
 151
 152                 l->object->matters_to_anchor = true;
 153                 l->object->generation = generation;
 154
 155                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
 156         }
 157 }
 158
 159 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 160         JobDependency *l, *last;
 161
 162         assert(j);
 163         assert(other);
 164         assert(j->unit == other->unit);
 165         assert(!j->installed);
 166
 167         /* Merges 'other' into 'j' and then deletes j. */
 168
 169         j->type = t;
 170         j->state = JOB_WAITING;
 171         j->forced = j->forced || other->forced;
 172
 173         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 174
 175         /* Patch us in as new owner of the JobDependency objects */
 176         last = NULL;
 177         LIST_FOREACH(subject, l, other->subject_list) {
 178                 assert(l->subject == other);
 179                 l->subject = j;
 180                 last = l;
 181         }
 182
 183         /* Merge both lists */
 184         if (last) {
 185                 last->subject_next = j->subject_list;
 186                 if (j->subject_list)
 187                         j->subject_list->subject_prev = last;
 188                 j->subject_list = other->subject_list;
 189         }
 190
 191         /* Patch us in as new owner of the JobDependency objects */
 192         last = NULL;
 193         LIST_FOREACH(object, l, other->object_list) {
 194                 assert(l->object == other);
 195                 l->object = j;
 196                 last = l;
 197         }
 198
 199         /* Merge both lists */
 200         if (last) {
 201                 last->object_next = j->object_list;
 202                 if (j->object_list)
 203                         j->object_list->object_prev = last;
 204                 j->object_list = other->object_list;
 205         }
 206
 207         /* Kill the other job */
 208         other->subject_list = NULL;
 209         other->object_list = NULL;
 210         transaction_delete_job(m, other);
 211 }
 212
 213 static int delete_one_unmergeable_job(Manager *m, Job *j) {
 214         Job *k;
 215
 216         assert(j);
 217
 218         /* Tries to delete one item in the linked list
 219          * j->transaction_next->transaction_next->... that conflicts
 220          * whith another one, in an attempt to make an inconsistent
 221          * transaction work. */
 222
 223         /* We rely here on the fact that if a merged with b does not
 224          * merge with c, either a or b merge with c neither */
 225         LIST_FOREACH(transaction, j, j)
 226                 LIST_FOREACH(transaction, k, j->transaction_next) {
 227                         Job *d;
 228
 229                         /* Is this one mergeable? Then skip it */
 230                         if (job_type_is_mergeable(j->type, k->type))
 231                                 continue;
 232
 233                         /* Ok, we found two that conflict, let's see if we can
 234                          * drop one of them */
 235                         if (!j->matters_to_anchor)
 236                                 d = j;
 237                         else if (!k->matters_to_anchor)
 238                                 d = k;
 239                         else
 240                                 return -ENOEXEC;
 241
 242                         /* Ok, we can drop one, so let's do so. */
 243                         log_debug("Try to fix job merging by deleting job %s/%s", unit_id(d->unit), job_type_to_string(d->type));
 244                         transaction_delete_job(m, d);
 245                         return 0;
 246                 }
 247
 248         return -EINVAL;
 249 }
 250
 251 static int transaction_merge_jobs(Manager *m) {
 252         Job *j;
 253         Iterator i;
 254         int r;
 255
 256         assert(m);
 257
 258         /* First step, check whether any of the jobs for one specific
 259          * task conflict. If so, try to drop one of them. */
 260         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 261                 JobType t;
 262                 Job *k;
 263
 264                 t = j->type;
 265                 LIST_FOREACH(transaction, k, j->transaction_next) {
 266                         if ((r = job_type_merge(&t, k->type)) >= 0)
 267                                 continue;
 268
 269                         /* OK, we could not merge all jobs for this
 270                          * action. Let's see if we can get rid of one
 271                          * of them */
 272
 273                         if ((r = delete_one_unmergeable_job(m, j)) >= 0)
 274                                 /* Ok, we managed to drop one, now
 275                                  * let's ask our callers to call us
 276                                  * again after garbage collecting */
 277                                 return -EAGAIN;
 278
 279                         /* We couldn't merge anything. Failure */
 280                         return r;
 281                 }
 282         }
 283
 284         /* Second step, merge the jobs. */
 285         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 286                 JobType t = j->type;
 287                 Job *k;
 288
 289                 /* Merge all transactions */
 290                 LIST_FOREACH(transaction, k, j->transaction_next)
 291                         assert_se(job_type_merge(&t, k->type) == 0);
 292
 293                 /* If an active job is mergeable, merge it too */
 294                 if (j->unit->meta.job)
 295                         job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
 296
 297                 while ((k = j->transaction_next)) {
 298                         if (j->installed) {
 299                                 transaction_merge_and_delete_job(m, k, j, t);
 300                                 j = k;
 301                         } else
 302                                 transaction_merge_and_delete_job(m, j, k, t);
 303                 }
 304
 305                 assert(!j->transaction_next);
 306                 assert(!j->transaction_prev);
 307         }
 308
 309         return 0;
 310 }
 311
 312 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 313         assert(u);
 314         assert(!j->transaction_prev);
 315
 316         /* Checks whether at least one of the jobs for this unit
 317          * matters to the anchor. */
 318
 319         LIST_FOREACH(transaction, j, j)
 320                 if (j->matters_to_anchor)
 321                         return true;
 322
 323         return false;
 324 }
 325
 326 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 327         Iterator i;
 328         Unit *u;
 329         int r;
 330
 331         assert(m);
 332         assert(j);
 333         assert(!j->transaction_prev);
 334
 335         /* Does a recursive sweep through the ordering graph, looking
 336          * for a cycle. If we find cycle we try to break it. */
 337
 338         /* Did we find a cycle? */
 339         if (j->marker && j->generation == generation) {
 340                 Job *k;
 341
 342                 /* So, we already have been here. We have a
 343                  * cycle. Let's try to break it. We go backwards in
 344                  * our path and try to find a suitable job to
 345                  * remove. We use the marker to find our way back,
 346                  * since smart how we are we stored our way back in
 347                  * there. */
 348
 349                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 350
 351                         if (!k->installed &&
 352                             !unit_matters_to_anchor(k->unit, k)) {
 353                                 /* Ok, we can drop this one, so let's
 354                                  * do so. */
 355                                 log_debug("Breaking order cycle by deleting job %s/%s", unit_id(k->unit), job_type_to_string(k->type));
 356                                 transaction_delete_unit(m, k->unit);
 357                                 return -EAGAIN;
 358                         }
 359
 360                         /* Check if this in fact was the beginning of
 361                          * the cycle */
 362                         if (k == j)
 363                                 break;
 364                 }
 365
 366                 return -ENOEXEC;
 367         }
 368
 369         /* Make the marker point to where we come from, so that we can
 370          * find our way backwards if we want to break a cycle */
 371         j->marker = from;
 372         j->generation = generation;
 373
 374         /* We assume that the the dependencies are bidirectional, and
 375          * hence can ignore UNIT_AFTER */
 376         SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
 377                 Job *o;
 378
 379                 /* Is there a job for this unit? */
 380                 if (!(o = hashmap_get(m->transaction_jobs, u)))
 381
 382                         /* Ok, there is no job for this in the
 383                          * transaction, but maybe there is already one
 384                          * running? */
 385                         if (!(o = u->meta.job))
 386                                 continue;
 387
 388                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 389                         return r;
 390         }
 391
 392         return 0;
 393 }
 394
 395 static int transaction_verify_order(Manager *m, unsigned *generation) {
 396         Job *j;
 397         int r;
 398         Iterator i;
 399
 400         assert(m);
 401         assert(generation);
 402
 403         /* Check if the ordering graph is cyclic. If it is, try to fix
 404          * that up by dropping one of the jobs. */
 405
 406         HASHMAP_FOREACH(j, m->transaction_jobs, i)
 407                 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
 408                         return r;
 409
 410         return 0;
 411 }
 412
 413 static void transaction_collect_garbage(Manager *m) {
 414         bool again;
 415
 416         assert(m);
 417
 418         /* Drop jobs that are not required by any other job */
 419
 420         do {
 421                 Iterator i;
 422                 Job *j;
 423
 424                 again = false;
 425
 426                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 427                         if (j->object_list)
 428                                 continue;
 429
 430                         log_debug("Garbage collecting job %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 431                         transaction_delete_job(m, j);
 432                         again = true;
 433                         break;
 434                 }
 435
 436         } while (again);
 437 }
 438
 439 static int transaction_is_destructive(Manager *m, JobMode mode) {
 440         Iterator i;
 441         Job *j;
 442
 443         assert(m);
 444
 445         /* Checks whether applying this transaction means that
 446          * existing jobs would be replaced */
 447
 448         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 449
 450                 /* Assume merged */
 451                 assert(!j->transaction_prev);
 452                 assert(!j->transaction_next);
 453
 454                 if (j->unit->meta.job &&
 455                     j->unit->meta.job != j &&
 456                     !job_type_is_superset(j->type, j->unit->meta.job->type))
 457                         return -EEXIST;
 458         }
 459
 460         return 0;
 461 }
 462
 463 static void transaction_minimize_impact(Manager *m) {
 464         bool again;
 465         assert(m);
 466
 467         /* Drops all unnecessary jobs that reverse already active jobs
 468          * or that stop a running service. */
 469
 470         do {
 471                 Job *j;
 472                 Iterator i;
 473
 474                 again = false;
 475
 476                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 477                         LIST_FOREACH(transaction, j, j) {
 478
 479                                 /* If it matters, we shouldn't drop it */
 480                                 if (j->matters_to_anchor)
 481                                         continue;
 482
 483                                 /* Would this stop a running service?
 484                                  * Would this change an existing job?
 485                                  * If so, let's drop this entry */
 486                                 if ((j->type != JOB_STOP || UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(j->unit))) &&
 487                                     (!j->unit->meta.job  || job_type_is_conflicting(j->type, j->unit->meta.job->state)))
 488                                         continue;
 489
 490                                 /* Ok, let's get rid of this */
 491                                 log_debug("Deleting %s/%s to minimize impact", unit_id(j->unit), job_type_to_string(j->type));
 492                                 transaction_delete_job(m, j);
 493                                 again = true;
 494                                 break;
 495                         }
 496
 497                         if (again)
 498                                 break;
 499                 }
 500
 501         } while (again);
 502 }
 503
 504 static int transaction_apply(Manager *m, JobMode mode) {
 505         Iterator i;
 506         Job *j;
 507         int r;
 508
 509         /* Moves the transaction jobs to the set of active jobs */
 510
 511         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 512                 /* Assume merged */
 513                 assert(!j->transaction_prev);
 514                 assert(!j->transaction_next);
 515
 516                 if (j->installed)
 517                         continue;
 518
 519                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 520                         goto rollback;
 521         }
 522
 523         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 524                 if (j->installed)
 525                         continue;
 526
 527                 if (j->unit->meta.job)
 528                         job_free(j->unit->meta.job);
 529
 530                 j->unit->meta.job = j;
 531                 j->installed = true;
 532
 533                 /* We're fully installed. Now let's free data we don't
 534                  * need anymore. */
 535
 536                 assert(!j->transaction_next);
 537                 assert(!j->transaction_prev);
 538
 539         }
 540
 541         /* As last step, kill all remaining job dependencies. */
 542         HASHMAP_FOREACH(j, m->jobs, i) {
 543                 while (j->subject_list)
 544                         job_dependency_free(j->subject_list);
 545                 while (j->object_list)
 546                         job_dependency_free(j->object_list);
 547         }
 548
 549         assert(!m->transaction_anchor);
 550
 551         return 0;
 552
 553 rollback:
 554
 555         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 556                 if (j->installed)
 557                         continue;
 558
 559                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 560         }
 561
 562         return r;
 563 }
 564
 565 static int transaction_activate(Manager *m, JobMode mode) {
 566         int r;
 567         unsigned generation = 1;
 568
 569         assert(m);
 570
 571         /* This applies the changes recorded in transaction_jobs to
 572          * the actual list of jobs, if possible. */
 573
 574         /* First step: figure out which jobs matter */
 575         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 576
 577         /* Second step: Try not to stop any running services if
 578          * we don't have to. Don't try to reverse running
 579          * jobs if we don't have to. */
 580         transaction_minimize_impact(m);
 581
 582         for (;;) {
 583                 /* Third step: Let's remove unneeded jobs that might
 584                  * be lurking. */
 585                 transaction_collect_garbage(m);
 586
 587                 /* Fourth step: verify order makes sense and correct
 588                  * cycles if necessary and possible */
 589                 if ((r = transaction_verify_order(m, &generation)) >= 0)
 590                         break;
 591
 592                 if (r != -EAGAIN)
 593                         goto rollback;
 594
 595                 /* Let's see if the resulting transaction ordering
 596                  * graph is still cyclic... */
 597         }
 598
 599         for (;;) {
 600                 /* Fifth step: let's drop unmergeable entries if
 601                  * necessary and possible, merge entries we can
 602                  * merge */
 603                 if ((r = transaction_merge_jobs(m)) >= 0)
 604                         break;
 605
 606                 if (r != -EAGAIN)
 607                         goto rollback;
 608
 609                 /* Sixth step: an entry got dropped, let's garbage
 610                  * collect its dependencies. */
 611                 transaction_collect_garbage(m);
 612
 613                 /* Let's see if the resulting transaction still has
 614                  * unmergeable entries ... */
 615         }
 616
 617         /* Seventh step: check whether we can actually apply this */
 618         if (mode == JOB_FAIL)
 619                 if ((r = transaction_is_destructive(m, mode)) < 0)
 620                         goto rollback;
 621
 622         /* Eights step: apply changes */
 623         if ((r = transaction_apply(m, mode)) < 0)
 624                 goto rollback;
 625
 626         assert(hashmap_isempty(m->transaction_jobs));
 627         assert(!m->transaction_anchor);
 628
 629         return 0;
 630
 631 rollback:
 632         transaction_abort(m);
 633         return r;
 634 }
 635
 636 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool force, bool *is_new) {
 637         Job *j, *f;
 638         int r;
 639
 640         assert(m);
 641         assert(unit);
 642
 643         /* Looks for an axisting prospective job and returns that. If
 644          * it doesn't exist it is created and added to the prospective
 645          * jobs list. */
 646
 647         f = hashmap_get(m->transaction_jobs, unit);
 648
 649         LIST_FOREACH(transaction, j, f) {
 650                 assert(j->unit == unit);
 651
 652                 if (j->type == type) {
 653                         if (is_new)
 654                                 *is_new = false;
 655                         return j;
 656                 }
 657         }
 658
 659         if (unit->meta.job && unit->meta.job->type == type)
 660                 j = unit->meta.job;
 661         else if (!(j = job_new(m, type, unit)))
 662                 return NULL;
 663
 664         j->generation = 0;
 665         j->marker = NULL;
 666         j->matters_to_anchor = false;
 667         j->forced = force;
 668
 669         LIST_PREPEND(Job, transaction, f, j);
 670
 671         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
 672                 job_free(j);
 673                 return NULL;
 674         }
 675
 676         if (is_new)
 677                 *is_new = true;
 678
 679         return j;
 680 }
 681
 682 void manager_transaction_unlink_job(Manager *m, Job *j) {
 683         assert(m);
 684         assert(j);
 685
 686         if (j->transaction_prev)
 687                 j->transaction_prev->transaction_next = j->transaction_next;
 688         else if (j->transaction_next)
 689                 hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
 690         else
 691                 hashmap_remove_value(m->transaction_jobs, j->unit, j);
 692
 693         if (j->transaction_next)
 694                 j->transaction_next->transaction_prev = j->transaction_prev;
 695
 696         j->transaction_prev = j->transaction_next = NULL;
 697
 698         while (j->subject_list)
 699                 job_dependency_free(j->subject_list);
 700
 701         while (j->object_list) {
 702                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 703
 704                 job_dependency_free(j->object_list);
 705
 706                 if (other) {
 707                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
 708                                   unit_id(other->unit), job_type_to_string(other->type),
 709                                   unit_id(j->unit), job_type_to_string(j->type));
 710                         transaction_delete_job(m, other);
 711                 }
 712         }
 713 }
 714
 715 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Unit *unit, Job *by, bool matters, bool force, Job **_ret) {
 716         Job *ret;
 717         Iterator i;
 718         Unit *dep;
 719         int r;
 720         bool is_new;
 721
 722         assert(m);
 723         assert(type < _JOB_TYPE_MAX);
 724         assert(unit);
 725
 726         if (unit->meta.load_state != UNIT_LOADED)
 727                 return -EINVAL;
 728
 729         if (!unit_job_is_applicable(unit, type))
 730                 return -EBADR;
 731
 732         /* First add the job. */
 733         if (!(ret = transaction_add_one_job(m, type, unit, force, &is_new)))
 734                 return -ENOMEM;
 735
 736         /* Then, add a link to the job. */
 737         if (!job_dependency_new(by, ret, matters))
 738                 return -ENOMEM;
 739
 740         if (is_new) {
 741                 /* Finally, recursively add in all dependencies. */
 742                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 743                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
 744                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 745                                         goto fail;
 746                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 747                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 748                                         goto fail;
 749                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
 750                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR)
 751                                         goto fail;
 752                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
 753                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 754                                         goto fail;
 755                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUISITE], i)
 756                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 757                                         goto fail;
 758                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
 759                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 760                                         goto fail;
 761
 762                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 763
 764                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
 765                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 766                                         goto fail;
 767                 }
 768
 769                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 770         }
 771
 772         return 0;
 773
 774 fail:
 775         return r;
 776 }
 777
 778 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool force, Job **_ret) {
 779         int r;
 780         Job *ret;
 781
 782         assert(m);
 783         assert(type < _JOB_TYPE_MAX);
 784         assert(unit);
 785         assert(mode < _JOB_MODE_MAX);
 786
 787         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, force, &ret))) {
 788                 transaction_abort(m);
 789                 return r;
 790         }
 791
 792         if ((r = transaction_activate(m, mode)) < 0)
 793                 return r;
 794
 795         if (_ret)
 796                 *_ret = ret;
 797
 798         return 0;
 799 }
 800
 801 Job *manager_get_job(Manager *m, uint32_t id) {
 802         assert(m);
 803
 804         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 805 }
 806
 807 Unit *manager_get_unit(Manager *m, const char *name) {
 808         assert(m);
 809         assert(name);
 810
 811         return hashmap_get(m->units, name);
 812 }
 813
 814 static void dispatch_load_queue(Manager *m) {
 815         Meta *meta;
 816
 817         assert(m);
 818
 819         /* Make sure we are not run recursively */
 820         if (m->dispatching_load_queue)
 821                 return;
 822
 823         m->dispatching_load_queue = true;
 824
 825         /* Dispatches the load queue. Takes a unit from the queue and
 826          * tries to load its data until the queue is empty */
 827
 828         while ((meta = m->load_queue)) {
 829                 assert(meta->in_load_queue);
 830
 831                 unit_load(UNIT(meta));
 832         }
 833
 834         m->dispatching_load_queue = false;
 835 }
 836
 837 int manager_load_unit(Manager *m, const char *path, Unit **_ret) {
 838         Unit *ret;
 839         int r;
 840         const char *name;
 841
 842         assert(m);
 843         assert(path);
 844         assert(_ret);
 845
 846         /* This will load the service information files, but not actually
 847          * start any services or anything. */
 848
 849         name = file_name_from_path(path);
 850
 851         if ((ret = manager_get_unit(m, name))) {
 852                 *_ret = ret;
 853                 return 0;
 854         }
 855
 856         if (!(ret = unit_new(m)))
 857                 return -ENOMEM;
 858
 859         if (is_path(path)) {
 860                 if (!(ret->meta.load_path = strdup(path))) {
 861                         unit_free(ret);
 862                         return -ENOMEM;
 863                 }
 864         }
 865
 866         if ((r = unit_add_name(ret, name)) < 0) {
 867                 unit_free(ret);
 868                 return r;
 869         }
 870
 871         unit_add_to_load_queue(ret);
 872         dispatch_load_queue(m);
 873
 874         *_ret = ret;
 875         return 0;
 876 }
 877
 878 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
 879         Iterator i;
 880         Job *j;
 881
 882         assert(s);
 883         assert(f);
 884
 885         HASHMAP_FOREACH(j, s->jobs, i)
 886                 job_dump(j, f, prefix);
 887 }
 888
 889 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
 890         Iterator i;
 891         Unit *u;
 892         const char *t;
 893
 894         assert(s);
 895         assert(f);
 896
 897         HASHMAP_FOREACH_KEY(u, t, s->units, i)
 898                 if (unit_id(u) == t)
 899                         unit_dump(u, f, prefix);
 900 }
 901
 902 void manager_clear_jobs(Manager *m) {
 903         Job *j;
 904
 905         assert(m);
 906
 907         transaction_abort(m);
 908
 909         while ((j = hashmap_first(m->jobs)))
 910                 job_free(j);
 911 }
 912
 913 void manager_dispatch_run_queue(Manager *m) {
 914         Job *j;
 915
 916         if (m->dispatching_run_queue)
 917                 return;
 918
 919         m->dispatching_run_queue = true;
 920
 921         while ((j = m->run_queue)) {
 922                 assert(j->installed);
 923                 assert(j->in_run_queue);
 924
 925                 job_run_and_invalidate(j);
 926         }
 927
 928         m->dispatching_run_queue = false;
 929 }
 930
 931 static int manager_dispatch_sigchld(Manager *m) {
 932         assert(m);
 933
 934         for (;;) {
 935                 siginfo_t si;
 936                 Unit *u;
 937
 938                 zero(si);
 939                 if (waitid(P_ALL, 0, &si, WNOHANG) < 0)
 940                         return -errno;
 941
 942                 if (si.si_pid == 0)
 943                         break;
 944
 945                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
 946                         continue;
 947
 948                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
 949                         continue;
 950
 951                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
 952         }
 953
 954         return 0;
 955 }
 956
 957 static int manager_process_signal_fd(Manager *m) {
 958         ssize_t n;
 959         struct signalfd_siginfo sfsi;
 960         bool sigchld = false;
 961
 962         assert(m);
 963
 964         for (;;) {
 965                 if ((n = read(m->signal_fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
 966
 967                         if (n >= 0)
 968                                 return -EIO;
 969
 970                         if (errno == EAGAIN)
 971                                 return 0;
 972
 973                         return -errno;
 974                 }
 975
 976                 if (sfsi.ssi_signo == SIGCHLD)
 977                         sigchld = true;
 978         }
 979
 980         if (sigchld)
 981                 return manager_dispatch_sigchld(m);
 982
 983         return 0;
 984 }
 985
 986 static int process_event(Manager *m, struct epoll_event *ev) {
 987         int r;
 988
 989         assert(m);
 990         assert(ev);
 991
 992         switch (ev->data.u32) {
 993
 994                 case MANAGER_SIGNAL:
 995                         assert(ev->data.fd == m->signal_fd);
 996
 997                         /* An incoming signal? */
 998                         if (ev->events != POLLIN)
 999                                 return -EINVAL;
1000
1001                         if ((r = manager_process_signal_fd(m)) < 0)
1002                                 return -r;
1003
1004                         break;
1005
1006                 case MANAGER_FD: {
1007                         Unit *u;
1008
1009                         /* Some fd event, to be dispatched to the units */
1010                         assert_se(u = ev->data.ptr);
1011                         UNIT_VTABLE(u)->fd_event(u, ev->data.fd, ev->events);
1012                         break;
1013                 }
1014
1015                 case MANAGER_TIMER: {
1016                         Unit *u;
1017                         uint64_t v;
1018                         ssize_t k;
1019
1020                         /* Some timer event, to be dispatched to the units */
1021                         if ((k = read(ev->data.fd, &v, sizeof(v))) != sizeof(v)) {
1022
1023                                 if (k < 0 && (errno == EINTR || errno == EAGAIN))
1024                                         break;
1025
1026                                 return k < 0 ? -errno : -EIO;
1027                         }
1028
1029                         assert_se(u = ev->data.ptr);
1030                         UNIT_VTABLE(u)->timer_event(u, ev->data.fd, v);
1031                         break;
1032                 }
1033
1034                 default:
1035                         assert_not_reached("Unknown epoll event type.");
1036         }
1037
1038         return 0;
1039 }
1040
1041 int manager_loop(Manager *m) {
1042         int r;
1043
1044         assert(m);
1045
1046         for (;;) {
1047                 struct epoll_event events[32];
1048                 int n, i;
1049
1050                 manager_dispatch_run_queue(m);
1051
1052                 if ((n = epoll_wait(m->epoll_fd, events, ELEMENTSOF(events), -1)) < 0) {
1053
1054                         if (errno == -EINTR)
1055                                 continue;
1056
1057                         return -errno;
1058                 }
1059
1060                 for (i = 0; i < n; i++)
1061                         if ((r = process_event(m, events + i)) < 0)
1062                                 return r;
1063         }
1064 }