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                 while (j->subject_list)
 540                         job_dependency_free(j->subject_list);
 541                 while (j->object_list)
 542                         job_dependency_free(j->object_list);
 543         }
 544
 545         m->transaction_anchor = NULL;
 546
 547         return 0;
 548
 549 rollback:
 550
 551         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 552                 if (j->installed)
 553                         continue;
 554
 555                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 556         }
 557
 558         return r;
 559 }
 560
 561 static int transaction_activate(Manager *m, JobMode mode) {
 562         int r;
 563         unsigned generation = 1;
 564
 565         assert(m);
 566
 567         /* This applies the changes recorded in transaction_jobs to
 568          * the actual list of jobs, if possible. */
 569
 570         /* First step: figure out which jobs matter */
 571         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 572
 573         /* Second step: Try not to stop any running services if
 574          * we don't have to. Don't try to reverse running
 575          * jobs if we don't have to. */
 576         transaction_minimize_impact(m);
 577
 578         for (;;) {
 579                 /* Third step: Let's remove unneeded jobs that might
 580                  * be lurking. */
 581                 transaction_collect_garbage(m);
 582
 583                 /* Fourth step: verify order makes sense and correct
 584                  * cycles if necessary and possible */
 585                 if ((r = transaction_verify_order(m, &generation)) >= 0)
 586                         break;
 587
 588                 if (r != -EAGAIN)
 589                         goto rollback;
 590
 591                 /* Let's see if the resulting transaction ordering
 592                  * graph is still cyclic... */
 593         }
 594
 595         for (;;) {
 596                 /* Fifth step: let's drop unmergeable entries if
 597                  * necessary and possible, merge entries we can
 598                  * merge */
 599                 if ((r = transaction_merge_jobs(m)) >= 0)
 600                         break;
 601
 602                 if (r != -EAGAIN)
 603                         goto rollback;
 604
 605                 /* Sixth step: an entry got dropped, let's garbage
 606                  * collect its dependencies. */
 607                 transaction_collect_garbage(m);
 608
 609                 /* Let's see if the resulting transaction still has
 610                  * unmergeable entries ... */
 611         }
 612
 613         /* Seventh step: check whether we can actually apply this */
 614         if (mode == JOB_FAIL)
 615                 if ((r = transaction_is_destructive(m, mode)) < 0)
 616                         goto rollback;
 617
 618         /* Eights step: apply changes */
 619         if ((r = transaction_apply(m, mode)) < 0)
 620                 goto rollback;
 621
 622         assert(hashmap_isempty(m->transaction_jobs));
 623         assert(!m->transaction_anchor);
 624
 625         return 0;
 626
 627 rollback:
 628         transaction_abort(m);
 629         return r;
 630 }
 631
 632 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool force, bool *is_new) {
 633         Job *j, *f;
 634         int r;
 635
 636         assert(m);
 637         assert(unit);
 638
 639         /* Looks for an axisting prospective job and returns that. If
 640          * it doesn't exist it is created and added to the prospective
 641          * jobs list. */
 642
 643         f = hashmap_get(m->transaction_jobs, unit);
 644
 645         LIST_FOREACH(transaction, j, f) {
 646                 assert(j->unit == unit);
 647
 648                 if (j->type == type) {
 649                         if (is_new)
 650                                 *is_new = false;
 651                         return j;
 652                 }
 653         }
 654
 655         if (unit->meta.job && unit->meta.job->type == type)
 656                 j = unit->meta.job;
 657         else if (!(j = job_new(m, type, unit)))
 658                 return NULL;
 659
 660         j->generation = 0;
 661         j->marker = NULL;
 662         j->matters_to_anchor = false;
 663         j->forced = force;
 664
 665         LIST_PREPEND(Job, transaction, f, j);
 666
 667         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
 668                 job_free(j);
 669                 return NULL;
 670         }
 671
 672         if (is_new)
 673                 *is_new = true;
 674
 675         return j;
 676 }
 677
 678 void manager_transaction_unlink_job(Manager *m, Job *j) {
 679         assert(m);
 680         assert(j);
 681
 682         if (j->transaction_prev)
 683                 j->transaction_prev->transaction_next = j->transaction_next;
 684         else if (j->transaction_next)
 685                 hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
 686         else
 687                 hashmap_remove_value(m->transaction_jobs, j->unit, j);
 688
 689         if (j->transaction_next)
 690                 j->transaction_next->transaction_prev = j->transaction_prev;
 691
 692         j->transaction_prev = j->transaction_next = NULL;
 693
 694         while (j->subject_list)
 695                 job_dependency_free(j->subject_list);
 696
 697         while (j->object_list) {
 698                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 699
 700                 job_dependency_free(j->object_list);
 701
 702                 if (other) {
 703                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
 704                                   unit_id(other->unit), job_type_to_string(other->type),
 705                                   unit_id(j->unit), job_type_to_string(j->type));
 706                         transaction_delete_job(m, other);
 707                 }
 708         }
 709 }
 710
 711 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Unit *unit, Job *by, bool matters, bool force, Job **_ret) {
 712         Job *ret;
 713         Iterator i;
 714         Unit *dep;
 715         int r;
 716         bool is_new;
 717
 718         assert(m);
 719         assert(type < _JOB_TYPE_MAX);
 720         assert(unit);
 721
 722         if (unit->meta.load_state != UNIT_LOADED)
 723                 return -EINVAL;
 724
 725         if (!unit_job_is_applicable(unit, type))
 726                 return -EBADR;
 727
 728         /* First add the job. */
 729         if (!(ret = transaction_add_one_job(m, type, unit, force, &is_new)))
 730                 return -ENOMEM;
 731
 732         /* Then, add a link to the job. */
 733         if (!job_dependency_new(by, ret, matters))
 734                 return -ENOMEM;
 735
 736         if (is_new) {
 737                 /* Finally, recursively add in all dependencies. */
 738                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 739                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
 740                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 741                                         goto fail;
 742                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 743                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 744                                         goto fail;
 745                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
 746                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR)
 747                                         goto fail;
 748                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
 749                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 750                                         goto fail;
 751                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUISITE], i)
 752                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 753                                         goto fail;
 754                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
 755                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 756                                         goto fail;
 757
 758                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 759
 760                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
 761                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 762                                         goto fail;
 763                 }
 764
 765                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 766         }
 767
 768         return 0;
 769
 770 fail:
 771         return r;
 772 }
 773
 774 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool force, Job **_ret) {
 775         int r;
 776         Job *ret;
 777
 778         assert(m);
 779         assert(type < _JOB_TYPE_MAX);
 780         assert(unit);
 781         assert(mode < _JOB_MODE_MAX);
 782
 783         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, force, &ret))) {
 784                 transaction_abort(m);
 785                 return r;
 786         }
 787
 788         if ((r = transaction_activate(m, mode)) < 0)
 789                 return r;
 790
 791         if (_ret)
 792                 *_ret = ret;
 793
 794         return 0;
 795 }
 796
 797 Job *manager_get_job(Manager *m, uint32_t id) {
 798         assert(m);
 799
 800         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 801 }
 802
 803 Unit *manager_get_unit(Manager *m, const char *name) {
 804         assert(m);
 805         assert(name);
 806
 807         return hashmap_get(m->units, name);
 808 }
 809
 810 static void dispatch_load_queue(Manager *m) {
 811         Meta *meta;
 812
 813         assert(m);
 814
 815         /* Make sure we are not run recursively */
 816         if (m->dispatching_load_queue)
 817                 return;
 818
 819         m->dispatching_load_queue = true;
 820
 821         /* Dispatches the load queue. Takes a unit from the queue and
 822          * tries to load its data until the queue is empty */
 823
 824         while ((meta = m->load_queue)) {
 825                 assert(meta->in_load_queue);
 826
 827                 unit_load(UNIT(meta));
 828         }
 829
 830         m->dispatching_load_queue = false;
 831 }
 832
 833 int manager_load_unit(Manager *m, const char *name, Unit **_ret) {
 834         Unit *ret;
 835         int r;
 836
 837         assert(m);
 838         assert(name);
 839         assert(_ret);
 840
 841         /* This will load the service information files, but not actually
 842          * start any services or anything */
 843
 844         if ((ret = manager_get_unit(m, name))) {
 845                 *_ret = ret;
 846                 return 0;
 847         }
 848
 849         if (!(ret = unit_new(m)))
 850                 return -ENOMEM;
 851
 852         if ((r = unit_add_name(ret, name)) < 0) {
 853                 unit_free(ret);
 854                 return r;
 855         }
 856
 857         unit_add_to_load_queue(ret);
 858         dispatch_load_queue(m);
 859
 860         *_ret = ret;
 861         return 0;
 862 }
 863
 864 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
 865         Iterator i;
 866         Job *j;
 867
 868         assert(s);
 869         assert(f);
 870
 871         HASHMAP_FOREACH(j, s->jobs, i)
 872                 job_dump(j, f, prefix);
 873 }
 874
 875 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
 876         Iterator i;
 877         Unit *u;
 878         const char *t;
 879
 880         assert(s);
 881         assert(f);
 882
 883         HASHMAP_FOREACH_KEY(u, t, s->units, i)
 884                 if (unit_id(u) == t)
 885                         unit_dump(u, f, prefix);
 886 }
 887
 888 void manager_clear_jobs(Manager *m) {
 889         Job *j;
 890
 891         assert(m);
 892
 893         transaction_abort(m);
 894
 895         while ((j = hashmap_first(m->jobs)))
 896                 job_free(j);
 897 }
 898
 899 void manager_dispatch_run_queue(Manager *m) {
 900         Job *j;
 901
 902         if (m->dispatching_run_queue)
 903                 return;
 904
 905         m->dispatching_run_queue = true;
 906
 907         while ((j = m->run_queue)) {
 908                 assert(j->installed);
 909                 assert(j->in_run_queue);
 910
 911                 job_run_and_invalidate(j);
 912         }
 913
 914         m->dispatching_run_queue = false;
 915 }
 916
 917 static int manager_dispatch_sigchld(Manager *m) {
 918         assert(m);
 919
 920         for (;;) {
 921                 siginfo_t si;
 922                 Unit *u;
 923
 924                 zero(si);
 925                 if (waitid(P_ALL, 0, &si, WNOHANG) < 0)
 926                         return -errno;
 927
 928                 if (si.si_pid == 0)
 929                         break;
 930
 931                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
 932                         continue;
 933
 934                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
 935                         continue;
 936
 937                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
 938         }
 939
 940         return 0;
 941 }
 942
 943 static int manager_process_signal_fd(Manager *m) {
 944         ssize_t n;
 945         struct signalfd_siginfo sfsi;
 946         bool sigchld = false;
 947
 948         assert(m);
 949
 950         for (;;) {
 951                 if ((n = read(m->signal_fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
 952
 953                         if (n >= 0)
 954                                 return -EIO;
 955
 956                         if (errno == EAGAIN)
 957                                 return 0;
 958
 959                         return -errno;
 960                 }
 961
 962                 if (sfsi.ssi_signo == SIGCHLD)
 963                         sigchld = true;
 964         }
 965
 966         if (sigchld)
 967                 return manager_dispatch_sigchld(m);
 968
 969         return 0;
 970 }
 971
 972 static int process_event(Manager *m, struct epoll_event *ev) {
 973         int r;
 974
 975         assert(m);
 976         assert(ev);
 977
 978         switch (ev->data.u32) {
 979
 980                 case MANAGER_SIGNAL:
 981                         assert(ev->data.fd == m->signal_fd);
 982
 983                         /* An incoming signal? */
 984                         if (ev->events != POLLIN)
 985                                 return -EINVAL;
 986
 987                         if ((r = manager_process_signal_fd(m)) < 0)
 988                                 return -r;
 989
 990                         break;
 991
 992                 case MANAGER_FD: {
 993                         Unit *u;
 994
 995                         /* Some fd event, to be dispatched to the units */
 996                         assert_se(u = ev->data.ptr);
 997                         UNIT_VTABLE(u)->fd_event(u, ev->data.fd, ev->events);
 998                         break;
 999                 }
1000
1001                 case MANAGER_TIMER: {
1002                         Unit *u;
1003                         uint64_t v;
1004                         ssize_t k;
1005
1006                         /* Some timer event, to be dispatched to the units */
1007                         if ((k = read(ev->data.fd, &v, sizeof(v))) != sizeof(v)) {
1008
1009                                 if (k < 0 && (errno == EINTR || errno == EAGAIN))
1010                                         break;
1011
1012                                 return k < 0 ? -errno : -EIO;
1013                         }
1014
1015                         assert_se(u = ev->data.ptr);
1016                         UNIT_VTABLE(u)->timer_event(u, ev->data.fd, v);
1017                         break;
1018                 }
1019
1020                 default:
1021                         assert_not_reached("Unknown epoll event type.");
1022         }
1023
1024         return 0;
1025 }
1026
1027 int manager_loop(Manager *m) {
1028         int r;
1029
1030         assert(m);
1031
1032         for (;;) {
1033                 struct epoll_event events[32];
1034                 int n, i;
1035
1036                 manager_dispatch_run_queue(m);
1037
1038                 if ((n = epoll_wait(m->epoll_fd, events, ELEMENTSOF(events), -1)) < 0) {
1039
1040                         if (errno == -EINTR)
1041                                 continue;
1042
1043                         return -errno;
1044                 }
1045
1046                 for (i = 0; i < n; i++)
1047                         if ((r = process_event(m, events + i)) < 0)
1048                                 return r;
1049         }
1050 }