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