src/core/transaction.c

   1 #include "transaction.h"
   2 #include "bus-errors.h"
   3
   4 static void transaction_unlink_job(Transaction *tr, Job *j, bool delete_dependencies);
   5
   6 static void transaction_delete_job(Transaction *tr, Job *j, bool delete_dependencies) {
   7         assert(tr);
   8         assert(j);
   9
  10         /* Deletes one job from the transaction */
  11
  12         transaction_unlink_job(tr, j, delete_dependencies);
  13
  14         if (!j->installed)
  15                 job_free(j);
  16 }
  17
  18 static void transaction_delete_unit(Transaction *tr, Unit *u) {
  19         Job *j;
  20
  21         /* Deletes all jobs associated with a certain unit from the
  22          * transaction */
  23
  24         while ((j = hashmap_get(tr->jobs, u)))
  25                 transaction_delete_job(tr, j, true);
  26 }
  27
  28 void transaction_abort(Transaction *tr) {
  29         Job *j;
  30
  31         assert(tr);
  32
  33         while ((j = hashmap_first(tr->jobs)))
  34                 transaction_delete_job(tr, j, true);
  35
  36         assert(hashmap_isempty(tr->jobs));
  37
  38         assert(!tr->anchor);
  39 }
  40
  41 static void transaction_find_jobs_that_matter_to_anchor(Transaction *tr, Job *j, unsigned generation) {
  42         JobDependency *l;
  43
  44         assert(tr);
  45
  46         /* A recursive sweep through the graph that marks all units
  47          * that matter to the anchor job, i.e. are directly or
  48          * indirectly a dependency of the anchor job via paths that
  49          * are fully marked as mattering. */
  50
  51         if (j)
  52                 l = j->subject_list;
  53         else
  54                 l = tr->anchor;
  55
  56         LIST_FOREACH(subject, l, l) {
  57
  58                 /* This link does not matter */
  59                 if (!l->matters)
  60                         continue;
  61
  62                 /* This unit has already been marked */
  63                 if (l->object->generation == generation)
  64                         continue;
  65
  66                 l->object->matters_to_anchor = true;
  67                 l->object->generation = generation;
  68
  69                 transaction_find_jobs_that_matter_to_anchor(tr, l->object, generation);
  70         }
  71 }
  72
  73 static void transaction_merge_and_delete_job(Transaction *tr, Job *j, Job *other, JobType t) {
  74         JobDependency *l, *last;
  75
  76         assert(j);
  77         assert(other);
  78         assert(j->unit == other->unit);
  79         assert(!j->installed);
  80
  81         /* Merges 'other' into 'j' and then deletes 'other'. */
  82
  83         j->type = t;
  84         j->state = JOB_WAITING;
  85         j->override = j->override || other->override;
  86
  87         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
  88
  89         /* Patch us in as new owner of the JobDependency objects */
  90         last = NULL;
  91         LIST_FOREACH(subject, l, other->subject_list) {
  92                 assert(l->subject == other);
  93                 l->subject = j;
  94                 last = l;
  95         }
  96
  97         /* Merge both lists */
  98         if (last) {
  99                 last->subject_next = j->subject_list;
 100                 if (j->subject_list)
 101                         j->subject_list->subject_prev = last;
 102                 j->subject_list = other->subject_list;
 103         }
 104
 105         /* Patch us in as new owner of the JobDependency objects */
 106         last = NULL;
 107         LIST_FOREACH(object, l, other->object_list) {
 108                 assert(l->object == other);
 109                 l->object = j;
 110                 last = l;
 111         }
 112
 113         /* Merge both lists */
 114         if (last) {
 115                 last->object_next = j->object_list;
 116                 if (j->object_list)
 117                         j->object_list->object_prev = last;
 118                 j->object_list = other->object_list;
 119         }
 120
 121         /* Kill the other job */
 122         other->subject_list = NULL;
 123         other->object_list = NULL;
 124         transaction_delete_job(tr, other, true);
 125 }
 126
 127 static bool job_is_conflicted_by(Job *j) {
 128         JobDependency *l;
 129
 130         assert(j);
 131
 132         /* Returns true if this job is pulled in by a least one
 133          * ConflictedBy dependency. */
 134
 135         LIST_FOREACH(object, l, j->object_list)
 136                 if (l->conflicts)
 137                         return true;
 138
 139         return false;
 140 }
 141
 142 static int delete_one_unmergeable_job(Transaction *tr, Job *j) {
 143         Job *k;
 144
 145         assert(j);
 146
 147         /* Tries to delete one item in the linked list
 148          * j->transaction_next->transaction_next->... that conflicts
 149          * with another one, in an attempt to make an inconsistent
 150          * transaction work. */
 151
 152         /* We rely here on the fact that if a merged with b does not
 153          * merge with c, either a or b merge with c neither */
 154         LIST_FOREACH(transaction, j, j)
 155                 LIST_FOREACH(transaction, k, j->transaction_next) {
 156                         Job *d;
 157
 158                         /* Is this one mergeable? Then skip it */
 159                         if (job_type_is_mergeable(j->type, k->type))
 160                                 continue;
 161
 162                         /* Ok, we found two that conflict, let's see if we can
 163                          * drop one of them */
 164                         if (!j->matters_to_anchor && !k->matters_to_anchor) {
 165
 166                                 /* Both jobs don't matter, so let's
 167                                  * find the one that is smarter to
 168                                  * remove. Let's think positive and
 169                                  * rather remove stops then starts --
 170                                  * except if something is being
 171                                  * stopped because it is conflicted by
 172                                  * another unit in which case we
 173                                  * rather remove the start. */
 174
 175                                 log_debug("Looking at job %s/%s conflicted_by=%s", j->unit->id, job_type_to_string(j->type), yes_no(j->type == JOB_STOP && job_is_conflicted_by(j)));
 176                                 log_debug("Looking at job %s/%s conflicted_by=%s", k->unit->id, job_type_to_string(k->type), yes_no(k->type == JOB_STOP && job_is_conflicted_by(k)));
 177
 178                                 if (j->type == JOB_STOP) {
 179
 180                                         if (job_is_conflicted_by(j))
 181                                                 d = k;
 182                                         else
 183                                                 d = j;
 184
 185                                 } else if (k->type == JOB_STOP) {
 186
 187                                         if (job_is_conflicted_by(k))
 188                                                 d = j;
 189                                         else
 190                                                 d = k;
 191                                 } else
 192                                         d = j;
 193
 194                         } else if (!j->matters_to_anchor)
 195                                 d = j;
 196                         else if (!k->matters_to_anchor)
 197                                 d = k;
 198                         else
 199                                 return -ENOEXEC;
 200
 201                         /* Ok, we can drop one, so let's do so. */
 202                         log_debug("Fixing conflicting jobs by deleting job %s/%s", d->unit->id, job_type_to_string(d->type));
 203                         transaction_delete_job(tr, d, true);
 204                         return 0;
 205                 }
 206
 207         return -EINVAL;
 208 }
 209
 210 static int transaction_merge_jobs(Transaction *tr, DBusError *e) {
 211         Job *j;
 212         Iterator i;
 213         int r;
 214
 215         assert(tr);
 216
 217         /* First step, check whether any of the jobs for one specific
 218          * task conflict. If so, try to drop one of them. */
 219         HASHMAP_FOREACH(j, tr->jobs, i) {
 220                 JobType t;
 221                 Job *k;
 222
 223                 t = j->type;
 224                 LIST_FOREACH(transaction, k, j->transaction_next) {
 225                         if (job_type_merge(&t, k->type) >= 0)
 226                                 continue;
 227
 228                         /* OK, we could not merge all jobs for this
 229                          * action. Let's see if we can get rid of one
 230                          * of them */
 231
 232                         r = delete_one_unmergeable_job(tr, j);
 233                         if (r >= 0)
 234                                 /* Ok, we managed to drop one, now
 235                                  * let's ask our callers to call us
 236                                  * again after garbage collecting */
 237                                 return -EAGAIN;
 238
 239                         /* We couldn't merge anything. Failure */
 240                         dbus_set_error(e, BUS_ERROR_TRANSACTION_JOBS_CONFLICTING, "Transaction contains conflicting jobs '%s' and '%s' for %s. Probably contradicting requirement dependencies configured.",
 241                                        job_type_to_string(t), job_type_to_string(k->type), k->unit->id);
 242                         return r;
 243                 }
 244         }
 245
 246         /* Second step, merge the jobs. */
 247         HASHMAP_FOREACH(j, tr->jobs, i) {
 248                 JobType t = j->type;
 249                 Job *k;
 250
 251                 /* Merge all transactions */
 252                 LIST_FOREACH(transaction, k, j->transaction_next)
 253                         assert_se(job_type_merge(&t, k->type) == 0);
 254
 255                 /* If an active job is mergeable, merge it too */
 256                 if (j->unit->job)
 257                         job_type_merge(&t, j->unit->job->type); /* Might fail. Which is OK */
 258
 259                 while ((k = j->transaction_next)) {
 260                         if (j->installed) {
 261                                 transaction_merge_and_delete_job(tr, k, j, t);
 262                                 j = k;
 263                         } else
 264                                 transaction_merge_and_delete_job(tr, j, k, t);
 265                 }
 266
 267                 if (j->unit->job && !j->installed)
 268                         transaction_merge_and_delete_job(tr, j, j->unit->job, t);
 269
 270                 assert(!j->transaction_next);
 271                 assert(!j->transaction_prev);
 272         }
 273
 274         return 0;
 275 }
 276
 277 static void transaction_drop_redundant(Transaction *tr) {
 278         bool again;
 279
 280         assert(tr);
 281
 282         /* Goes through the transaction and removes all jobs that are
 283          * a noop */
 284
 285         do {
 286                 Job *j;
 287                 Iterator i;
 288
 289                 again = false;
 290
 291                 HASHMAP_FOREACH(j, tr->jobs, i) {
 292                         bool changes_something = false;
 293                         Job *k;
 294
 295                         LIST_FOREACH(transaction, k, j) {
 296
 297                                 if (!job_is_anchor(k) &&
 298                                     (k->installed || job_type_is_redundant(k->type, unit_active_state(k->unit))) &&
 299                                     (!k->unit->job || !job_type_is_conflicting(k->type, k->unit->job->type)))
 300                                         continue;
 301
 302                                 changes_something = true;
 303                                 break;
 304                         }
 305
 306                         if (changes_something)
 307                                 continue;
 308
 309                         /* log_debug("Found redundant job %s/%s, dropping.", j->unit->id, job_type_to_string(j->type)); */
 310                         transaction_delete_job(tr, j, false);
 311                         again = true;
 312                         break;
 313                 }
 314
 315         } while (again);
 316 }
 317
 318 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 319         assert(u);
 320         assert(!j->transaction_prev);
 321
 322         /* Checks whether at least one of the jobs for this unit
 323          * matters to the anchor. */
 324
 325         LIST_FOREACH(transaction, j, j)
 326                 if (j->matters_to_anchor)
 327                         return true;
 328
 329         return false;
 330 }
 331
 332 static int transaction_verify_order_one(Transaction *tr, Job *j, Job *from, unsigned generation, DBusError *e) {
 333         Iterator i;
 334         Unit *u;
 335         int r;
 336
 337         assert(tr);
 338         assert(j);
 339         assert(!j->transaction_prev);
 340
 341         /* Does a recursive sweep through the ordering graph, looking
 342          * for a cycle. If we find cycle we try to break it. */
 343
 344         /* Have we seen this before? */
 345         if (j->generation == generation) {
 346                 Job *k, *delete;
 347
 348                 /* If the marker is NULL we have been here already and
 349                  * decided the job was loop-free from here. Hence
 350                  * shortcut things and return right-away. */
 351                 if (!j->marker)
 352                         return 0;
 353
 354                 /* So, the marker is not NULL and we already have been
 355                  * here. We have a cycle. Let's try to break it. We go
 356                  * backwards in our path and try to find a suitable
 357                  * job to remove. We use the marker to find our way
 358                  * back, since smart how we are we stored our way back
 359                  * in there. */
 360                 log_warning("Found ordering cycle on %s/%s", j->unit->id, job_type_to_string(j->type));
 361
 362                 delete = NULL;
 363                 for (k = from; k; k = ((k->generation == generation && k->marker != k) ? k->marker : NULL)) {
 364
 365                         log_info("Walked on cycle path to %s/%s", k->unit->id, job_type_to_string(k->type));
 366
 367                         if (!delete &&
 368                             !k->installed &&
 369                             !unit_matters_to_anchor(k->unit, k)) {
 370                                 /* Ok, we can drop this one, so let's
 371                                  * do so. */
 372                                 delete = k;
 373                         }
 374
 375                         /* Check if this in fact was the beginning of
 376                          * the cycle */
 377                         if (k == j)
 378                                 break;
 379                 }
 380
 381
 382                 if (delete) {
 383                         log_warning("Breaking ordering cycle by deleting job %s/%s", delete->unit->id, job_type_to_string(delete->type));
 384                         transaction_delete_unit(tr, delete->unit);
 385                         return -EAGAIN;
 386                 }
 387
 388                 log_error("Unable to break cycle");
 389
 390                 dbus_set_error(e, BUS_ERROR_TRANSACTION_ORDER_IS_CYCLIC, "Transaction order is cyclic. See system logs for details.");
 391                 return -ENOEXEC;
 392         }
 393
 394         /* Make the marker point to where we come from, so that we can
 395          * find our way backwards if we want to break a cycle. We use
 396          * a special marker for the beginning: we point to
 397          * ourselves. */
 398         j->marker = from ? from : j;
 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->dependencies[UNIT_BEFORE], i) {
 404                 Job *o;
 405
 406                 /* Is there a job for this unit? */
 407                 o = hashmap_get(tr->jobs, u);
 408                 if (!o) {
 409                         /* Ok, there is no job for this in the
 410                          * transaction, but maybe there is already one
 411                          * running? */
 412                         o = u->job;
 413                         if (!o)
 414                                 continue;
 415                 }
 416
 417                 r = transaction_verify_order_one(tr, o, j, generation, e);
 418                 if (r < 0)
 419                         return r;
 420         }
 421
 422         /* Ok, let's backtrack, and remember that this entry is not on
 423          * our path anymore. */
 424         j->marker = NULL;
 425
 426         return 0;
 427 }
 428
 429 static int transaction_verify_order(Transaction *tr, unsigned *generation, DBusError *e) {
 430         Job *j;
 431         int r;
 432         Iterator i;
 433         unsigned g;
 434
 435         assert(tr);
 436         assert(generation);
 437
 438         /* Check if the ordering graph is cyclic. If it is, try to fix
 439          * that up by dropping one of the jobs. */
 440
 441         g = (*generation)++;
 442
 443         HASHMAP_FOREACH(j, tr->jobs, i)
 444                 if ((r = transaction_verify_order_one(tr, j, NULL, g, e)) < 0)
 445                         return r;
 446
 447         return 0;
 448 }
 449
 450 static void transaction_collect_garbage(Transaction *tr) {
 451         bool again;
 452
 453         assert(tr);
 454
 455         /* Drop jobs that are not required by any other job */
 456
 457         do {
 458                 Iterator i;
 459                 Job *j;
 460
 461                 again = false;
 462
 463                 HASHMAP_FOREACH(j, tr->jobs, i) {
 464                         if (j->object_list) {
 465                                 /* log_debug("Keeping job %s/%s because of %s/%s", */
 466                                 /*           j->unit->id, job_type_to_string(j->type), */
 467                                 /*           j->object_list->subject ? j->object_list->subject->unit->id : "root", */
 468                                 /*           j->object_list->subject ? job_type_to_string(j->object_list->subject->type) : "root"); */
 469                                 continue;
 470                         }
 471
 472                         /* log_debug("Garbage collecting job %s/%s", j->unit->id, job_type_to_string(j->type)); */
 473                         transaction_delete_job(tr, j, true);
 474                         again = true;
 475                         break;
 476                 }
 477
 478         } while (again);
 479 }
 480
 481 static int transaction_is_destructive(Transaction *tr, DBusError *e) {
 482         Iterator i;
 483         Job *j;
 484
 485         assert(tr);
 486
 487         /* Checks whether applying this transaction means that
 488          * existing jobs would be replaced */
 489
 490         HASHMAP_FOREACH(j, tr->jobs, i) {
 491
 492                 /* Assume merged */
 493                 assert(!j->transaction_prev);
 494                 assert(!j->transaction_next);
 495
 496                 if (j->unit->job &&
 497                     j->unit->job != j &&
 498                     !job_type_is_superset(j->type, j->unit->job->type)) {
 499
 500                         dbus_set_error(e, BUS_ERROR_TRANSACTION_IS_DESTRUCTIVE, "Transaction is destructive.");
 501                         return -EEXIST;
 502                 }
 503         }
 504
 505         return 0;
 506 }
 507
 508 static void transaction_minimize_impact(Transaction *tr) {
 509         bool again;
 510         assert(tr);
 511
 512         /* Drops all unnecessary jobs that reverse already active jobs
 513          * or that stop a running service. */
 514
 515         do {
 516                 Job *j;
 517                 Iterator i;
 518
 519                 again = false;
 520
 521                 HASHMAP_FOREACH(j, tr->jobs, i) {
 522                         LIST_FOREACH(transaction, j, j) {
 523                                 bool stops_running_service, changes_existing_job;
 524
 525                                 /* If it matters, we shouldn't drop it */
 526                                 if (j->matters_to_anchor)
 527                                         continue;
 528
 529                                 /* Would this stop a running service?
 530                                  * Would this change an existing job?
 531                                  * If so, let's drop this entry */
 532
 533                                 stops_running_service =
 534                                         j->type == JOB_STOP && UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(j->unit));
 535
 536                                 changes_existing_job =
 537                                         j->unit->job &&
 538                                         job_type_is_conflicting(j->type, j->unit->job->type);
 539
 540                                 if (!stops_running_service && !changes_existing_job)
 541                                         continue;
 542
 543                                 if (stops_running_service)
 544                                         log_debug("%s/%s would stop a running service.", j->unit->id, job_type_to_string(j->type));
 545
 546                                 if (changes_existing_job)
 547                                         log_debug("%s/%s would change existing job.", j->unit->id, job_type_to_string(j->type));
 548
 549                                 /* Ok, let's get rid of this */
 550                                 log_debug("Deleting %s/%s to minimize impact.", j->unit->id, job_type_to_string(j->type));
 551
 552                                 transaction_delete_job(tr, j, true);
 553                                 again = true;
 554                                 break;
 555                         }
 556
 557                         if (again)
 558                                 break;
 559                 }
 560
 561         } while (again);
 562 }
 563
 564 static int transaction_apply(Transaction *tr, Manager *m, JobMode mode) {
 565         Iterator i;
 566         Job *j;
 567         int r;
 568
 569         /* Moves the transaction jobs to the set of active jobs */
 570
 571         if (mode == JOB_ISOLATE) {
 572
 573                 /* When isolating first kill all installed jobs which
 574                  * aren't part of the new transaction */
 575         rescan:
 576                 HASHMAP_FOREACH(j, m->jobs, i) {
 577                         assert(j->installed);
 578
 579                         if (hashmap_get(tr->jobs, j->unit))
 580                                 continue;
 581
 582                         /* 'j' itself is safe to remove, but if other jobs
 583                            are invalidated recursively, our iterator may become
 584                            invalid and we need to start over. */
 585                         if (job_finish_and_invalidate(j, JOB_CANCELED) > 0)
 586                                 goto rescan;
 587                 }
 588         }
 589
 590         HASHMAP_FOREACH(j, tr->jobs, i) {
 591                 /* Assume merged */
 592                 assert(!j->transaction_prev);
 593                 assert(!j->transaction_next);
 594
 595                 if (j->installed)
 596                         continue;
 597
 598                 r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j);
 599                 if (r < 0)
 600                         goto rollback;
 601         }
 602
 603         while ((j = hashmap_steal_first(tr->jobs))) {
 604                 Job *uj;
 605                 if (j->installed) {
 606                         /* log_debug("Skipping already installed job %s/%s as %u", j->unit->id, job_type_to_string(j->type), (unsigned) j->id); */
 607                         continue;
 608                 }
 609
 610                 uj = j->unit->job;
 611                 if (uj) {
 612                         job_uninstall(uj);
 613                         job_free(uj);
 614                 }
 615
 616                 j->unit->job = j;
 617                 j->installed = true;
 618                 m->n_installed_jobs ++;
 619
 620                 /* We're fully installed. Now let's free data we don't
 621                  * need anymore. */
 622
 623                 assert(!j->transaction_next);
 624                 assert(!j->transaction_prev);
 625
 626                 /* Clean the job dependencies */
 627                 transaction_unlink_job(tr, j, false);
 628
 629                 job_add_to_run_queue(j);
 630                 job_add_to_dbus_queue(j);
 631                 job_start_timer(j);
 632
 633                 log_debug("Installed new job %s/%s as %u", j->unit->id, job_type_to_string(j->type), (unsigned) j->id);
 634         }
 635
 636         assert(!tr->anchor);
 637
 638         return 0;
 639
 640 rollback:
 641
 642         HASHMAP_FOREACH(j, tr->jobs, i) {
 643                 if (j->installed)
 644                         continue;
 645
 646                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 647         }
 648
 649         return r;
 650 }
 651
 652 int transaction_activate(Transaction *tr, Manager *m, JobMode mode, DBusError *e) {
 653         int r;
 654         unsigned generation = 1;
 655
 656         assert(tr);
 657
 658         /* This applies the changes recorded in tr->jobs to
 659          * the actual list of jobs, if possible. */
 660
 661         /* First step: figure out which jobs matter */
 662         transaction_find_jobs_that_matter_to_anchor(tr, NULL, generation++);
 663
 664         /* Second step: Try not to stop any running services if
 665          * we don't have to. Don't try to reverse running
 666          * jobs if we don't have to. */
 667         if (mode == JOB_FAIL)
 668                 transaction_minimize_impact(tr);
 669
 670         /* Third step: Drop redundant jobs */
 671         transaction_drop_redundant(tr);
 672
 673         for (;;) {
 674                 /* Fourth step: Let's remove unneeded jobs that might
 675                  * be lurking. */
 676                 if (mode != JOB_ISOLATE)
 677                         transaction_collect_garbage(tr);
 678
 679                 /* Fifth step: verify order makes sense and correct
 680                  * cycles if necessary and possible */
 681                 r = transaction_verify_order(tr, &generation, e);
 682                 if (r >= 0)
 683                         break;
 684
 685                 if (r != -EAGAIN) {
 686                         log_warning("Requested transaction contains an unfixable cyclic ordering dependency: %s", bus_error(e, r));
 687                         return r;
 688                 }
 689
 690                 /* Let's see if the resulting transaction ordering
 691                  * graph is still cyclic... */
 692         }
 693
 694         for (;;) {
 695                 /* Sixth step: let's drop unmergeable entries if
 696                  * necessary and possible, merge entries we can
 697                  * merge */
 698                 r = transaction_merge_jobs(tr, e);
 699                 if (r >= 0)
 700                         break;
 701
 702                 if (r != -EAGAIN) {
 703                         log_warning("Requested transaction contains unmergeable jobs: %s", bus_error(e, r));
 704                         return r;
 705                 }
 706
 707                 /* Seventh step: an entry got dropped, let's garbage
 708                  * collect its dependencies. */
 709                 if (mode != JOB_ISOLATE)
 710                         transaction_collect_garbage(tr);
 711
 712                 /* Let's see if the resulting transaction still has
 713                  * unmergeable entries ... */
 714         }
 715
 716         /* Eights step: Drop redundant jobs again, if the merging now allows us to drop more. */
 717         transaction_drop_redundant(tr);
 718
 719         /* Ninth step: check whether we can actually apply this */
 720         if (mode == JOB_FAIL) {
 721                 r = transaction_is_destructive(tr, e);
 722                 if (r < 0) {
 723                         log_notice("Requested transaction contradicts existing jobs: %s", bus_error(e, r));
 724                         return r;
 725                 }
 726         }
 727
 728         /* Tenth step: apply changes */
 729         r = transaction_apply(tr, m, mode);
 730         if (r < 0) {
 731                 log_warning("Failed to apply transaction: %s", strerror(-r));
 732                 return r;
 733         }
 734
 735         assert(hashmap_isempty(tr->jobs));
 736         assert(!tr->anchor);
 737
 738         return 0;
 739 }
 740
 741 static Job* transaction_add_one_job(Transaction *tr, JobType type, Unit *unit, bool override, bool *is_new) {
 742         Job *j, *f;
 743
 744         assert(tr);
 745         assert(unit);
 746
 747         /* Looks for an existing prospective job and returns that. If
 748          * it doesn't exist it is created and added to the prospective
 749          * jobs list. */
 750
 751         f = hashmap_get(tr->jobs, unit);
 752
 753         LIST_FOREACH(transaction, j, f) {
 754                 assert(j->unit == unit);
 755
 756                 if (j->type == type) {
 757                         if (is_new)
 758                                 *is_new = false;
 759                         return j;
 760                 }
 761         }
 762
 763         j = job_new(unit, type);
 764         if (!j)
 765                 return NULL;
 766
 767         j->generation = 0;
 768         j->marker = NULL;
 769         j->matters_to_anchor = false;
 770         j->override = override;
 771
 772         LIST_PREPEND(Job, transaction, f, j);
 773
 774         if (hashmap_replace(tr->jobs, unit, f) < 0) {
 775                 LIST_REMOVE(Job, transaction, f, j);
 776                 job_free(j);
 777                 return NULL;
 778         }
 779
 780         if (is_new)
 781                 *is_new = true;
 782
 783         /* log_debug("Added job %s/%s to transaction.", unit->id, job_type_to_string(type)); */
 784
 785         return j;
 786 }
 787
 788 static void transaction_job_dependency_free(Transaction *tr, JobDependency *l) {
 789         if (!l->subject)
 790                 LIST_REMOVE(JobDependency, subject, tr->anchor, l);
 791         job_dependency_free(l);
 792 }
 793
 794 static void transaction_unlink_job(Transaction *tr, Job *j, bool delete_dependencies) {
 795         assert(tr);
 796         assert(j);
 797
 798         if (j->transaction_prev)
 799                 j->transaction_prev->transaction_next = j->transaction_next;
 800         else if (j->transaction_next)
 801                 hashmap_replace(tr->jobs, j->unit, j->transaction_next);
 802         else
 803                 hashmap_remove_value(tr->jobs, j->unit, j);
 804
 805         if (j->transaction_next)
 806                 j->transaction_next->transaction_prev = j->transaction_prev;
 807
 808         j->transaction_prev = j->transaction_next = NULL;
 809
 810         while (j->subject_list)
 811                 transaction_job_dependency_free(tr, j->subject_list);
 812
 813         while (j->object_list) {
 814                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 815
 816                 transaction_job_dependency_free(tr, j->object_list);
 817
 818                 if (other && delete_dependencies) {
 819                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
 820                                   other->unit->id, job_type_to_string(other->type),
 821                                   j->unit->id, job_type_to_string(j->type));
 822                         transaction_delete_job(tr, other, delete_dependencies);
 823                 }
 824         }
 825 }
 826
 827 int transaction_add_job_and_dependencies(
 828                 Transaction *tr,
 829                 JobType type,
 830                 Unit *unit,
 831                 Job *by,
 832                 bool matters,
 833                 bool override,
 834                 bool conflicts,
 835                 bool ignore_requirements,
 836                 bool ignore_order,
 837                 DBusError *e,
 838                 Job **_ret) {
 839         Job *ret;
 840         JobDependency *l;
 841         Iterator i;
 842         Unit *dep;
 843         int r;
 844         bool is_new;
 845
 846         assert(tr);
 847         assert(type < _JOB_TYPE_MAX);
 848         assert(unit);
 849
 850         /* log_debug("Pulling in %s/%s from %s/%s", */
 851         /*           unit->id, job_type_to_string(type), */
 852         /*           by ? by->unit->id : "NA", */
 853         /*           by ? job_type_to_string(by->type) : "NA"); */
 854
 855         if (unit->load_state != UNIT_LOADED &&
 856             unit->load_state != UNIT_ERROR &&
 857             unit->load_state != UNIT_MASKED) {
 858                 dbus_set_error(e, BUS_ERROR_LOAD_FAILED, "Unit %s is not loaded properly.", unit->id);
 859                 return -EINVAL;
 860         }
 861
 862         if (type != JOB_STOP && unit->load_state == UNIT_ERROR) {
 863                 dbus_set_error(e, BUS_ERROR_LOAD_FAILED,
 864                                "Unit %s failed to load: %s. "
 865                                "See system logs and 'systemctl status %s' for details.",
 866                                unit->id,
 867                                strerror(-unit->load_error),
 868                                unit->id);
 869                 return -EINVAL;
 870         }
 871
 872         if (type != JOB_STOP && unit->load_state == UNIT_MASKED) {
 873                 dbus_set_error(e, BUS_ERROR_MASKED, "Unit %s is masked.", unit->id);
 874                 return -EINVAL;
 875         }
 876
 877         if (!unit_job_is_applicable(unit, type)) {
 878                 dbus_set_error(e, BUS_ERROR_JOB_TYPE_NOT_APPLICABLE, "Job type %s is not applicable for unit %s.", job_type_to_string(type), unit->id);
 879                 return -EBADR;
 880         }
 881
 882         /* First add the job. */
 883         ret = transaction_add_one_job(tr, type, unit, override, &is_new);
 884         if (!ret)
 885                 return -ENOMEM;
 886
 887         ret->ignore_order = ret->ignore_order || ignore_order;
 888
 889         /* Then, add a link to the job. */
 890         l = job_dependency_new(by, ret, matters, conflicts);
 891         if (!l)
 892                 return -ENOMEM;
 893
 894         /* If the link has no subject job, it's the anchor link. */
 895         if (!by)
 896                 LIST_PREPEND(JobDependency, subject, tr->anchor, l);
 897
 898         if (is_new && !ignore_requirements) {
 899                 Set *following;
 900
 901                 /* If we are following some other unit, make sure we
 902                  * add all dependencies of everybody following. */
 903                 if (unit_following_set(ret->unit, &following) > 0) {
 904                         SET_FOREACH(dep, following, i) {
 905                                 r = transaction_add_job_and_dependencies(tr, type, dep, ret, false, override, false, false, ignore_order, e, NULL);
 906                                 if (r < 0) {
 907                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->id, bus_error(e, r));
 908
 909                                         if (e)
 910                                                 dbus_error_free(e);
 911                                 }
 912                         }
 913
 914                         set_free(following);
 915                 }
 916
 917                 /* Finally, recursively add in all dependencies. */
 918                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 919                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_REQUIRES], i) {
 920                                 r = transaction_add_job_and_dependencies(tr, JOB_START, dep, ret, true, override, false, false, ignore_order, e, NULL);
 921                                 if (r < 0) {
 922                                         if (r != -EBADR)
 923                                                 goto fail;
 924
 925                                         if (e)
 926                                                 dbus_error_free(e);
 927                                 }
 928                         }
 929
 930                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_BIND_TO], i) {
 931                                 r = transaction_add_job_and_dependencies(tr, JOB_START, dep, ret, true, override, false, false, ignore_order, e, NULL);
 932                                 if (r < 0) {
 933                                         if (r != -EBADR)
 934                                                 goto fail;
 935
 936                                         if (e)
 937                                                 dbus_error_free(e);
 938                                 }
 939                         }
 940
 941                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_REQUIRES_OVERRIDABLE], i) {
 942                                 r = transaction_add_job_and_dependencies(tr, JOB_START, dep, ret, !override, override, false, false, ignore_order, e, NULL);
 943                                 if (r < 0) {
 944                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->id, bus_error(e, r));
 945
 946                                         if (e)
 947                                                 dbus_error_free(e);
 948                                 }
 949                         }
 950
 951                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_WANTS], i) {
 952                                 r = transaction_add_job_and_dependencies(tr, JOB_START, dep, ret, false, false, false, false, ignore_order, e, NULL);
 953                                 if (r < 0) {
 954                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->id, bus_error(e, r));
 955
 956                                         if (e)
 957                                                 dbus_error_free(e);
 958                                 }
 959                         }
 960
 961                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_REQUISITE], i) {
 962                                 r = transaction_add_job_and_dependencies(tr, JOB_VERIFY_ACTIVE, dep, ret, true, override, false, false, ignore_order, e, NULL);
 963                                 if (r < 0) {
 964                                         if (r != -EBADR)
 965                                                 goto fail;
 966
 967                                         if (e)
 968                                                 dbus_error_free(e);
 969                                 }
 970                         }
 971
 972                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_REQUISITE_OVERRIDABLE], i) {
 973                                 r = transaction_add_job_and_dependencies(tr, JOB_VERIFY_ACTIVE, dep, ret, !override, override, false, false, ignore_order, e, NULL);
 974                                 if (r < 0) {
 975                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->id, bus_error(e, r));
 976
 977                                         if (e)
 978                                                 dbus_error_free(e);
 979                                 }
 980                         }
 981
 982                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_CONFLICTS], i) {
 983                                 r = transaction_add_job_and_dependencies(tr, JOB_STOP, dep, ret, true, override, true, false, ignore_order, e, NULL);
 984                                 if (r < 0) {
 985                                         if (r != -EBADR)
 986                                                 goto fail;
 987
 988                                         if (e)
 989                                                 dbus_error_free(e);
 990                                 }
 991                         }
 992
 993                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_CONFLICTED_BY], i) {
 994                                 r = transaction_add_job_and_dependencies(tr, JOB_STOP, dep, ret, false, override, false, false, ignore_order, e, NULL);
 995                                 if (r < 0) {
 996                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", dep->id, bus_error(e, r));
 997
 998                                         if (e)
 999                                                 dbus_error_free(e);
1000                                 }
1001                         }
1002
1003                 }
1004
1005                 if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
1006
1007                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_REQUIRED_BY], i) {
1008                                 r = transaction_add_job_and_dependencies(tr, type, dep, ret, true, override, false, false, ignore_order, e, NULL);
1009                                 if (r < 0) {
1010                                         if (r != -EBADR)
1011                                                 goto fail;
1012
1013                                         if (e)
1014                                                 dbus_error_free(e);
1015                                 }
1016                         }
1017
1018                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_BOUND_BY], i) {
1019                                 r = transaction_add_job_and_dependencies(tr, type, dep, ret, true, override, false, false, ignore_order, e, NULL);
1020                                 if (r < 0) {
1021                                         if (r != -EBADR)
1022                                                 goto fail;
1023
1024                                         if (e)
1025                                                 dbus_error_free(e);
1026                                 }
1027                         }
1028                 }
1029
1030                 if (type == JOB_RELOAD || type == JOB_RELOAD_OR_START) {
1031
1032                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_PROPAGATE_RELOAD_TO], i) {
1033                                 r = transaction_add_job_and_dependencies(tr, JOB_RELOAD, dep, ret, false, override, false, false, ignore_order, e, NULL);
1034                                 if (r < 0) {
1035                                         log_warning("Cannot add dependency reload job for unit %s, ignoring: %s", dep->id, bus_error(e, r));
1036
1037                                         if (e)
1038                                                 dbus_error_free(e);
1039                                 }
1040                         }
1041                 }
1042
1043                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
1044         }
1045
1046         if (_ret)
1047                 *_ret = ret;
1048
1049         return 0;
1050
1051 fail:
1052         return r;
1053 }
1054
1055 int transaction_add_isolate_jobs(Transaction *tr, Manager *m) {
1056         Iterator i;
1057         Unit *u;
1058         char *k;
1059         int r;
1060
1061         assert(tr);
1062         assert(m);
1063
1064         HASHMAP_FOREACH_KEY(u, k, m->units, i) {
1065
1066                 /* ignore aliases */
1067                 if (u->id != k)
1068                         continue;
1069
1070                 if (u->ignore_on_isolate)
1071                         continue;
1072
1073                 /* No need to stop inactive jobs */
1074                 if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(u)) && !u->job)
1075                         continue;
1076
1077                 /* Is there already something listed for this? */
1078                 if (hashmap_get(tr->jobs, u))
1079                         continue;
1080
1081                 r = transaction_add_job_and_dependencies(tr, JOB_STOP, u, NULL, true, false, false, false, false, NULL, NULL);
1082                 if (r < 0)
1083                         log_warning("Cannot add isolate job for unit %s, ignoring: %s", u->id, strerror(-r));
1084         }
1085
1086         return 0;
1087 }
1088
1089 Transaction *transaction_new(void) {
1090         Transaction *tr;
1091
1092         tr = new0(Transaction, 1);
1093         if (!tr)
1094                 return NULL;
1095
1096         tr->jobs = hashmap_new(trivial_hash_func, trivial_compare_func);
1097         if (!tr->jobs) {
1098                 free(tr);
1099                 return NULL;
1100         }
1101
1102         return tr;
1103 }
1104
1105 void transaction_free(Transaction *tr) {
1106         assert(hashmap_isempty(tr->jobs));
1107         hashmap_free(tr->jobs);
1108         free(tr);
1109 }