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