manager.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <assert.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <sys/epoll.h>
   7 #include <signal.h>
   8 #include <sys/signalfd.h>
   9 #include <sys/wait.h>
  10 #include <unistd.h>
  11 #include <sys/poll.h>
  12
  13 #include "manager.h"
  14 #include "hashmap.h"
  15 #include "macro.h"
  16 #include "strv.h"
  17 #include "log.h"
  18 #include "util.h"
  19 #include "ratelimit.h"
  20
  21 static int manager_setup_signals(Manager *m) {
  22         sigset_t mask;
  23         struct epoll_event ev;
  24
  25         assert(m);
  26
  27         assert_se(reset_all_signal_handlers() == 0);
  28
  29         assert_se(sigemptyset(&mask) == 0);
  30         assert_se(sigaddset(&mask, SIGCHLD) == 0);
  31         assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
  32         assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
  33         assert_se(sigaddset(&mask, SIGTERM) == 0);
  34         assert_se(sigaddset(&mask, SIGHUP) == 0);
  35         assert_se(sigaddset(&mask, SIGUSR1) == 0);
  36         assert_se(sigaddset(&mask, SIGUSR2) == 0);
  37         assert_se(sigaddset(&mask, SIGPIPE) == 0);
  38         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
  39
  40         m->signal_watch.type = WATCH_SIGNAL;
  41         if ((m->signal_watch.fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
  42                 return -errno;
  43
  44         zero(ev);
  45         ev.events = EPOLLIN;
  46         ev.data.ptr = &m->signal_watch;
  47
  48         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
  49                 return -errno;
  50
  51         return 0;
  52 }
  53
  54 Manager* manager_new(void) {
  55         Manager *m;
  56
  57         if (!(m = new0(Manager, 1)))
  58                 return NULL;
  59
  60         m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = -1;
  61         m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
  62
  63         if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
  64                 goto fail;
  65
  66         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  67                 goto fail;
  68
  69         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  70                 goto fail;
  71
  72         if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
  73                 goto fail;
  74
  75         if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
  76                 goto fail;
  77
  78         if (manager_setup_signals(m) < 0)
  79                 goto fail;
  80
  81         /* FIXME: this should be called only when the D-Bus bus daemon is running */
  82         if (bus_init(m) < 0)
  83                 goto fail;
  84
  85         return m;
  86
  87 fail:
  88         manager_free(m);
  89         return NULL;
  90 }
  91
  92 void manager_free(Manager *m) {
  93         UnitType c;
  94         Unit *u;
  95         Job *j;
  96
  97         assert(m);
  98
  99         while ((j = hashmap_first(m->transaction_jobs)))
 100                 job_free(j);
 101
 102         while ((u = hashmap_first(m->units)))
 103                 unit_free(u);
 104
 105         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 106                 if (unit_vtable[c]->shutdown)
 107                         unit_vtable[c]->shutdown(m);
 108
 109         bus_done(m);
 110
 111         hashmap_free(m->units);
 112         hashmap_free(m->jobs);
 113         hashmap_free(m->transaction_jobs);
 114         hashmap_free(m->watch_pids);
 115
 116         if (m->epoll_fd >= 0)
 117                 close_nointr(m->epoll_fd);
 118         if (m->signal_watch.fd >= 0)
 119                 close_nointr(m->signal_watch.fd);
 120
 121         free(m);
 122 }
 123
 124 int manager_coldplug(Manager *m) {
 125         int r;
 126         UnitType c;
 127         Iterator i;
 128         Unit *u;
 129         char *k;
 130
 131         assert(m);
 132
 133         /* First, let's ask every type to load all units from
 134          * disk/kernel that it might know */
 135         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 136                 if (unit_vtable[c]->enumerate)
 137                         if ((r = unit_vtable[c]->enumerate(m)) < 0)
 138                                 return r;
 139
 140         manager_dispatch_load_queue(m);
 141
 142         /* Then, let's set up their initial state. */
 143         HASHMAP_FOREACH_KEY(u, k, m->units, i) {
 144
 145                 /* ignore aliases */
 146                 if (unit_id(u) != k)
 147                         continue;
 148
 149                 if (UNIT_VTABLE(u)->coldplug)
 150                         if ((r = UNIT_VTABLE(u)->coldplug(u)) < 0)
 151                                 return r;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static void transaction_delete_job(Manager *m, Job *j) {
 158         assert(m);
 159         assert(j);
 160
 161         /* Deletes one job from the transaction */
 162
 163         manager_transaction_unlink_job(m, j);
 164
 165         if (!j->installed)
 166                 job_free(j);
 167 }
 168
 169 static void transaction_delete_unit(Manager *m, Unit *u) {
 170         Job *j;
 171
 172         /* Deletes all jobs associated with a certain unit from the
 173          * transaction */
 174
 175         while ((j = hashmap_get(m->transaction_jobs, u)))
 176                 transaction_delete_job(m, j);
 177 }
 178
 179 static void transaction_clean_dependencies(Manager *m) {
 180         Iterator i;
 181         Job *j;
 182
 183         assert(m);
 184
 185         /* Drops all dependencies of all installed jobs */
 186
 187         HASHMAP_FOREACH(j, m->jobs, i) {
 188                 while (j->subject_list)
 189                         job_dependency_free(j->subject_list);
 190                 while (j->object_list)
 191                         job_dependency_free(j->object_list);
 192         }
 193
 194         assert(!m->transaction_anchor);
 195 }
 196
 197 static void transaction_abort(Manager *m) {
 198         Job *j;
 199
 200         assert(m);
 201
 202         while ((j = hashmap_first(m->transaction_jobs)))
 203                 if (j->installed)
 204                         transaction_delete_job(m, j);
 205                 else
 206                         job_free(j);
 207
 208         assert(hashmap_isempty(m->transaction_jobs));
 209
 210         transaction_clean_dependencies(m);
 211 }
 212
 213 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
 214         JobDependency *l;
 215
 216         assert(m);
 217
 218         /* A recursive sweep through the graph that marks all units
 219          * that matter to the anchor job, i.e. are directly or
 220          * indirectly a dependency of the anchor job via paths that
 221          * are fully marked as mattering. */
 222
 223         if (j)
 224                 l = j->subject_list;
 225         else
 226                 l = m->transaction_anchor;
 227
 228         LIST_FOREACH(subject, l, l) {
 229
 230                 /* This link does not matter */
 231                 if (!l->matters)
 232                         continue;
 233
 234                 /* This unit has already been marked */
 235                 if (l->object->generation == generation)
 236                         continue;
 237
 238                 l->object->matters_to_anchor = true;
 239                 l->object->generation = generation;
 240
 241                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
 242         }
 243 }
 244
 245 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 246         JobDependency *l, *last;
 247
 248         assert(j);
 249         assert(other);
 250         assert(j->unit == other->unit);
 251         assert(!j->installed);
 252
 253         /* Merges 'other' into 'j' and then deletes j. */
 254
 255         j->type = t;
 256         j->state = JOB_WAITING;
 257         j->forced = j->forced || other->forced;
 258
 259         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 260
 261         /* Patch us in as new owner of the JobDependency objects */
 262         last = NULL;
 263         LIST_FOREACH(subject, l, other->subject_list) {
 264                 assert(l->subject == other);
 265                 l->subject = j;
 266                 last = l;
 267         }
 268
 269         /* Merge both lists */
 270         if (last) {
 271                 last->subject_next = j->subject_list;
 272                 if (j->subject_list)
 273                         j->subject_list->subject_prev = last;
 274                 j->subject_list = other->subject_list;
 275         }
 276
 277         /* Patch us in as new owner of the JobDependency objects */
 278         last = NULL;
 279         LIST_FOREACH(object, l, other->object_list) {
 280                 assert(l->object == other);
 281                 l->object = j;
 282                 last = l;
 283         }
 284
 285         /* Merge both lists */
 286         if (last) {
 287                 last->object_next = j->object_list;
 288                 if (j->object_list)
 289                         j->object_list->object_prev = last;
 290                 j->object_list = other->object_list;
 291         }
 292
 293         /* Kill the other job */
 294         other->subject_list = NULL;
 295         other->object_list = NULL;
 296         transaction_delete_job(m, other);
 297 }
 298
 299 static int delete_one_unmergeable_job(Manager *m, Job *j) {
 300         Job *k;
 301
 302         assert(j);
 303
 304         /* Tries to delete one item in the linked list
 305          * j->transaction_next->transaction_next->... that conflicts
 306          * whith another one, in an attempt to make an inconsistent
 307          * transaction work. */
 308
 309         /* We rely here on the fact that if a merged with b does not
 310          * merge with c, either a or b merge with c neither */
 311         LIST_FOREACH(transaction, j, j)
 312                 LIST_FOREACH(transaction, k, j->transaction_next) {
 313                         Job *d;
 314
 315                         /* Is this one mergeable? Then skip it */
 316                         if (job_type_is_mergeable(j->type, k->type))
 317                                 continue;
 318
 319                         /* Ok, we found two that conflict, let's see if we can
 320                          * drop one of them */
 321                         if (!j->matters_to_anchor)
 322                                 d = j;
 323                         else if (!k->matters_to_anchor)
 324                                 d = k;
 325                         else
 326                                 return -ENOEXEC;
 327
 328                         /* Ok, we can drop one, so let's do so. */
 329                         log_debug("Try to fix job merging by deleting job %s/%s", unit_id(d->unit), job_type_to_string(d->type));
 330                         transaction_delete_job(m, d);
 331                         return 0;
 332                 }
 333
 334         return -EINVAL;
 335 }
 336
 337 static int transaction_merge_jobs(Manager *m) {
 338         Job *j;
 339         Iterator i;
 340         int r;
 341
 342         assert(m);
 343
 344         /* First step, check whether any of the jobs for one specific
 345          * task conflict. If so, try to drop one of them. */
 346         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 347                 JobType t;
 348                 Job *k;
 349
 350                 t = j->type;
 351                 LIST_FOREACH(transaction, k, j->transaction_next) {
 352                         if ((r = job_type_merge(&t, k->type)) >= 0)
 353                                 continue;
 354
 355                         /* OK, we could not merge all jobs for this
 356                          * action. Let's see if we can get rid of one
 357                          * of them */
 358
 359                         if ((r = delete_one_unmergeable_job(m, j)) >= 0)
 360                                 /* Ok, we managed to drop one, now
 361                                  * let's ask our callers to call us
 362                                  * again after garbage collecting */
 363                                 return -EAGAIN;
 364
 365                         /* We couldn't merge anything. Failure */
 366                         return r;
 367                 }
 368         }
 369
 370         /* Second step, merge the jobs. */
 371         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 372                 JobType t = j->type;
 373                 Job *k;
 374
 375                 /* Merge all transactions */
 376                 LIST_FOREACH(transaction, k, j->transaction_next)
 377                         assert_se(job_type_merge(&t, k->type) == 0);
 378
 379                 /* If an active job is mergeable, merge it too */
 380                 if (j->unit->meta.job)
 381                         job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
 382
 383                 while ((k = j->transaction_next)) {
 384                         if (j->installed) {
 385                                 transaction_merge_and_delete_job(m, k, j, t);
 386                                 j = k;
 387                         } else
 388                                 transaction_merge_and_delete_job(m, j, k, t);
 389                 }
 390
 391                 assert(!j->transaction_next);
 392                 assert(!j->transaction_prev);
 393         }
 394
 395         return 0;
 396 }
 397
 398 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 399         assert(u);
 400         assert(!j->transaction_prev);
 401
 402         /* Checks whether at least one of the jobs for this unit
 403          * matters to the anchor. */
 404
 405         LIST_FOREACH(transaction, j, j)
 406                 if (j->matters_to_anchor)
 407                         return true;
 408
 409         return false;
 410 }
 411
 412 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 413         Iterator i;
 414         Unit *u;
 415         int r;
 416
 417         assert(m);
 418         assert(j);
 419         assert(!j->transaction_prev);
 420
 421         /* Does a recursive sweep through the ordering graph, looking
 422          * for a cycle. If we find cycle we try to break it. */
 423
 424         /* Did we find a cycle? */
 425         if (j->marker && j->generation == generation) {
 426                 Job *k;
 427
 428                 /* So, we already have been here. We have a
 429                  * cycle. Let's try to break it. We go backwards in
 430                  * our path and try to find a suitable job to
 431                  * remove. We use the marker to find our way back,
 432                  * since smart how we are we stored our way back in
 433                  * there. */
 434
 435                 log_debug("Found cycle on %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 436
 437                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 438
 439                         log_debug("Walked on cycle path to %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 440
 441                         if (!k->installed &&
 442                             !unit_matters_to_anchor(k->unit, k)) {
 443                                 /* Ok, we can drop this one, so let's
 444                                  * do so. */
 445                                 log_debug("Breaking order cycle by deleting job %s/%s", unit_id(k->unit), job_type_to_string(k->type));
 446                                 transaction_delete_unit(m, k->unit);
 447                                 return -EAGAIN;
 448                         }
 449
 450                         /* Check if this in fact was the beginning of
 451                          * the cycle */
 452                         if (k == j)
 453                                 break;
 454                 }
 455
 456                 log_debug("Unable to break cycle");
 457
 458                 return -ENOEXEC;
 459         }
 460
 461         /* Make the marker point to where we come from, so that we can
 462          * find our way backwards if we want to break a cycle */
 463         j->marker = from;
 464         j->generation = generation;
 465
 466         /* We assume that the the dependencies are bidirectional, and
 467          * hence can ignore UNIT_AFTER */
 468         SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
 469                 Job *o;
 470
 471                 /* Is there a job for this unit? */
 472                 if (!(o = hashmap_get(m->transaction_jobs, u)))
 473
 474                         /* Ok, there is no job for this in the
 475                          * transaction, but maybe there is already one
 476                          * running? */
 477                         if (!(o = u->meta.job))
 478                                 continue;
 479
 480                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 481                         return r;
 482         }
 483
 484         /* Ok, let's backtrack, and remember that this entry is not on
 485          * our path anymore. */
 486         j->marker = NULL;
 487
 488         return 0;
 489 }
 490
 491 static int transaction_verify_order(Manager *m, unsigned *generation) {
 492         Job *j;
 493         int r;
 494         Iterator i;
 495
 496         assert(m);
 497         assert(generation);
 498
 499         /* Check if the ordering graph is cyclic. If it is, try to fix
 500          * that up by dropping one of the jobs. */
 501
 502         HASHMAP_FOREACH(j, m->transaction_jobs, i)
 503                 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
 504                         return r;
 505
 506         return 0;
 507 }
 508
 509 static void transaction_collect_garbage(Manager *m) {
 510         bool again;
 511
 512         assert(m);
 513
 514         /* Drop jobs that are not required by any other job */
 515
 516         do {
 517                 Iterator i;
 518                 Job *j;
 519
 520                 again = false;
 521
 522                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 523                         if (j->object_list)
 524                                 continue;
 525
 526                         log_debug("Garbage collecting job %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 527                         transaction_delete_job(m, j);
 528                         again = true;
 529                         break;
 530                 }
 531
 532         } while (again);
 533 }
 534
 535 static int transaction_is_destructive(Manager *m, JobMode mode) {
 536         Iterator i;
 537         Job *j;
 538
 539         assert(m);
 540
 541         /* Checks whether applying this transaction means that
 542          * existing jobs would be replaced */
 543
 544         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 545
 546                 /* Assume merged */
 547                 assert(!j->transaction_prev);
 548                 assert(!j->transaction_next);
 549
 550                 if (j->unit->meta.job &&
 551                     j->unit->meta.job != j &&
 552                     !job_type_is_superset(j->type, j->unit->meta.job->type))
 553                         return -EEXIST;
 554         }
 555
 556         return 0;
 557 }
 558
 559 static void transaction_minimize_impact(Manager *m) {
 560         bool again;
 561         assert(m);
 562
 563         /* Drops all unnecessary jobs that reverse already active jobs
 564          * or that stop a running service. */
 565
 566         do {
 567                 Job *j;
 568                 Iterator i;
 569
 570                 again = false;
 571
 572                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 573                         LIST_FOREACH(transaction, j, j) {
 574                                 bool stops_running_service, changes_existing_job;
 575
 576                                 /* If it matters, we shouldn't drop it */
 577                                 if (j->matters_to_anchor)
 578                                         continue;
 579
 580                                 /* Would this stop a running service?
 581                                  * Would this change an existing job?
 582                                  * If so, let's drop this entry */
 583
 584                                 stops_running_service =
 585                                         j->type == JOB_STOP && UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(j->unit));
 586
 587                                 changes_existing_job =
 588                                         j->unit->meta.job && job_type_is_conflicting(j->type, j->unit->meta.job->state);
 589
 590                                 if (!stops_running_service && !changes_existing_job)
 591                                         continue;
 592
 593                                 if (stops_running_service)
 594                                         log_debug("%s/%s would stop a running service.", unit_id(j->unit), job_type_to_string(j->type));
 595
 596                                 if (changes_existing_job)
 597                                         log_debug("%s/%s would change existing job.", unit_id(j->unit), job_type_to_string(j->type));
 598
 599                                 /* Ok, let's get rid of this */
 600                                 log_debug("Deleting %s/%s to minimize impact.", unit_id(j->unit), job_type_to_string(j->type));
 601
 602                                 transaction_delete_job(m, j);
 603                                 again = true;
 604                                 break;
 605                         }
 606
 607                         if (again)
 608                                 break;
 609                 }
 610
 611         } while (again);
 612 }
 613
 614 static int transaction_apply(Manager *m, JobMode mode) {
 615         Iterator i;
 616         Job *j;
 617         int r;
 618
 619         /* Moves the transaction jobs to the set of active jobs */
 620
 621         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 622                 /* Assume merged */
 623                 assert(!j->transaction_prev);
 624                 assert(!j->transaction_next);
 625
 626                 if (j->installed)
 627                         continue;
 628
 629                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 630                         goto rollback;
 631         }
 632
 633         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 634                 if (j->installed)
 635                         continue;
 636
 637                 if (j->unit->meta.job)
 638                         job_free(j->unit->meta.job);
 639
 640                 j->unit->meta.job = j;
 641                 j->installed = true;
 642
 643                 /* We're fully installed. Now let's free data we don't
 644                  * need anymore. */
 645
 646                 assert(!j->transaction_next);
 647                 assert(!j->transaction_prev);
 648
 649                 job_schedule_run(j);
 650         }
 651
 652         /* As last step, kill all remaining job dependencies. */
 653         transaction_clean_dependencies(m);
 654
 655         return 0;
 656
 657 rollback:
 658
 659         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 660                 if (j->installed)
 661                         continue;
 662
 663                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 664         }
 665
 666         return r;
 667 }
 668
 669 static int transaction_activate(Manager *m, JobMode mode) {
 670         int r;
 671         unsigned generation = 1;
 672
 673         assert(m);
 674
 675         /* This applies the changes recorded in transaction_jobs to
 676          * the actual list of jobs, if possible. */
 677
 678         /* First step: figure out which jobs matter */
 679         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 680
 681         /* Second step: Try not to stop any running services if
 682          * we don't have to. Don't try to reverse running
 683          * jobs if we don't have to. */
 684         transaction_minimize_impact(m);
 685
 686         for (;;) {
 687                 /* Third step: Let's remove unneeded jobs that might
 688                  * be lurking. */
 689                 transaction_collect_garbage(m);
 690
 691                 /* Fourth step: verify order makes sense and correct
 692                  * cycles if necessary and possible */
 693                 if ((r = transaction_verify_order(m, &generation)) >= 0)
 694                         break;
 695
 696                 if (r != -EAGAIN) {
 697                         log_debug("Requested transaction contains an unfixable cyclic ordering dependency: %s", strerror(-r));
 698                         goto rollback;
 699                 }
 700
 701                 /* Let's see if the resulting transaction ordering
 702                  * graph is still cyclic... */
 703         }
 704
 705         for (;;) {
 706                 /* Fifth step: let's drop unmergeable entries if
 707                  * necessary and possible, merge entries we can
 708                  * merge */
 709                 if ((r = transaction_merge_jobs(m)) >= 0)
 710                         break;
 711
 712                 if (r != -EAGAIN) {
 713                         log_debug("Requested transaction contains unmergable jobs: %s", strerror(-r));
 714                         goto rollback;
 715                 }
 716
 717                 /* Sixth step: an entry got dropped, let's garbage
 718                  * collect its dependencies. */
 719                 transaction_collect_garbage(m);
 720
 721                 /* Let's see if the resulting transaction still has
 722                  * unmergeable entries ... */
 723         }
 724
 725         /* Seventh step: check whether we can actually apply this */
 726         if (mode == JOB_FAIL)
 727                 if ((r = transaction_is_destructive(m, mode)) < 0) {
 728                         log_debug("Requested transaction contradicts existing jobs: %s", strerror(-r));
 729                         goto rollback;
 730                 }
 731
 732         /* Eights step: apply changes */
 733         if ((r = transaction_apply(m, mode)) < 0) {
 734                 log_debug("Failed to apply transaction: %s", strerror(-r));
 735                 goto rollback;
 736         }
 737
 738         assert(hashmap_isempty(m->transaction_jobs));
 739         assert(!m->transaction_anchor);
 740
 741         return 0;
 742
 743 rollback:
 744         transaction_abort(m);
 745         return r;
 746 }
 747
 748 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool force, bool *is_new) {
 749         Job *j, *f;
 750         int r;
 751
 752         assert(m);
 753         assert(unit);
 754
 755         /* Looks for an axisting prospective job and returns that. If
 756          * it doesn't exist it is created and added to the prospective
 757          * jobs list. */
 758
 759         f = hashmap_get(m->transaction_jobs, unit);
 760
 761         LIST_FOREACH(transaction, j, f) {
 762                 assert(j->unit == unit);
 763
 764                 if (j->type == type) {
 765                         if (is_new)
 766                                 *is_new = false;
 767                         return j;
 768                 }
 769         }
 770
 771         if (unit->meta.job && unit->meta.job->type == type)
 772                 j = unit->meta.job;
 773         else if (!(j = job_new(m, type, unit)))
 774                 return NULL;
 775
 776         j->generation = 0;
 777         j->marker = NULL;
 778         j->matters_to_anchor = false;
 779         j->forced = force;
 780
 781         LIST_PREPEND(Job, transaction, f, j);
 782
 783         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
 784                 job_free(j);
 785                 return NULL;
 786         }
 787
 788         if (is_new)
 789                 *is_new = true;
 790
 791         return j;
 792 }
 793
 794 void manager_transaction_unlink_job(Manager *m, Job *j) {
 795         assert(m);
 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(m->transaction_jobs, j->unit, j->transaction_next);
 802         else
 803                 hashmap_remove_value(m->transaction_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                 job_dependency_free(j->subject_list);
 812
 813         while (j->object_list) {
 814                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 815
 816                 job_dependency_free(j->object_list);
 817
 818                 if (other) {
 819                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
 820                                   unit_id(other->unit), job_type_to_string(other->type),
 821                                   unit_id(j->unit), job_type_to_string(j->type));
 822                         transaction_delete_job(m, other);
 823                 }
 824         }
 825 }
 826
 827 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Unit *unit, Job *by, bool matters, bool force, Job **_ret) {
 828         Job *ret;
 829         Iterator i;
 830         Unit *dep;
 831         int r;
 832         bool is_new;
 833
 834         assert(m);
 835         assert(type < _JOB_TYPE_MAX);
 836         assert(unit);
 837
 838         if (unit->meta.load_state != UNIT_LOADED)
 839                 return -EINVAL;
 840
 841         if (!unit_job_is_applicable(unit, type))
 842                 return -EBADR;
 843
 844         /* First add the job. */
 845         if (!(ret = transaction_add_one_job(m, type, unit, force, &is_new)))
 846                 return -ENOMEM;
 847
 848         /* Then, add a link to the job. */
 849         if (!job_dependency_new(by, ret, matters))
 850                 return -ENOMEM;
 851
 852         if (is_new) {
 853                 /* Finally, recursively add in all dependencies. */
 854                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 855                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
 856                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 857                                         goto fail;
 858                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 859                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 860                                         goto fail;
 861                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
 862                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR)
 863                                         goto fail;
 864                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
 865                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 866                                         goto fail;
 867                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUISITE], i)
 868                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 869                                         goto fail;
 870                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
 871                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 872                                         goto fail;
 873
 874                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 875
 876                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
 877                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 878                                         goto fail;
 879                 }
 880
 881                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 882         }
 883
 884         return 0;
 885
 886 fail:
 887         return r;
 888 }
 889
 890 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool force, Job **_ret) {
 891         int r;
 892         Job *ret;
 893
 894         assert(m);
 895         assert(type < _JOB_TYPE_MAX);
 896         assert(unit);
 897         assert(mode < _JOB_MODE_MAX);
 898
 899         log_debug("Trying to enqueue job %s/%s", unit_id(unit), job_type_to_string(type));
 900
 901         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, force, &ret))) {
 902                 transaction_abort(m);
 903                 return r;
 904         }
 905
 906         if ((r = transaction_activate(m, mode)) < 0)
 907                 return r;
 908
 909         log_debug("Enqueued job %s/%s", unit_id(unit), job_type_to_string(type));
 910
 911         if (_ret)
 912                 *_ret = ret;
 913
 914         return 0;
 915 }
 916
 917 Job *manager_get_job(Manager *m, uint32_t id) {
 918         assert(m);
 919
 920         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 921 }
 922
 923 Unit *manager_get_unit(Manager *m, const char *name) {
 924         assert(m);
 925         assert(name);
 926
 927         return hashmap_get(m->units, name);
 928 }
 929
 930 void manager_dispatch_load_queue(Manager *m) {
 931         Meta *meta;
 932
 933         assert(m);
 934
 935         /* Make sure we are not run recursively */
 936         if (m->dispatching_load_queue)
 937                 return;
 938
 939         m->dispatching_load_queue = true;
 940
 941         /* Dispatches the load queue. Takes a unit from the queue and
 942          * tries to load its data until the queue is empty */
 943
 944         while ((meta = m->load_queue)) {
 945                 assert(meta->in_load_queue);
 946
 947                 unit_load(UNIT(meta));
 948         }
 949
 950         m->dispatching_load_queue = false;
 951 }
 952
 953 int manager_load_unit(Manager *m, const char *path, Unit **_ret) {
 954         Unit *ret;
 955         int r;
 956         const char *name;
 957
 958         assert(m);
 959         assert(path);
 960         assert(_ret);
 961
 962         /* This will load the service information files, but not actually
 963          * start any services or anything. */
 964
 965         name = file_name_from_path(path);
 966
 967         if ((ret = manager_get_unit(m, name))) {
 968                 *_ret = ret;
 969                 return 0;
 970         }
 971
 972         if (!(ret = unit_new(m)))
 973                 return -ENOMEM;
 974
 975         if (is_path(path)) {
 976                 if (!(ret->meta.load_path = strdup(path))) {
 977                         unit_free(ret);
 978                         return -ENOMEM;
 979                 }
 980         }
 981
 982         if ((r = unit_add_name(ret, name)) < 0) {
 983                 unit_free(ret);
 984                 return r;
 985         }
 986
 987         unit_add_to_load_queue(ret);
 988         manager_dispatch_load_queue(m);
 989
 990         *_ret = ret;
 991         return 0;
 992 }
 993
 994 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
 995         Iterator i;
 996         Job *j;
 997
 998         assert(s);
 999         assert(f);
1000
1001         HASHMAP_FOREACH(j, s->jobs, i)
1002                 job_dump(j, f, prefix);
1003 }
1004
1005 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
1006         Iterator i;
1007         Unit *u;
1008         const char *t;
1009
1010         assert(s);
1011         assert(f);
1012
1013         HASHMAP_FOREACH_KEY(u, t, s->units, i)
1014                 if (unit_id(u) == t)
1015                         unit_dump(u, f, prefix);
1016 }
1017
1018 void manager_clear_jobs(Manager *m) {
1019         Job *j;
1020
1021         assert(m);
1022
1023         transaction_abort(m);
1024
1025         while ((j = hashmap_first(m->jobs)))
1026                 job_free(j);
1027 }
1028
1029 void manager_dispatch_run_queue(Manager *m) {
1030         Job *j;
1031
1032         if (m->dispatching_run_queue)
1033                 return;
1034
1035         m->dispatching_run_queue = true;
1036
1037         while ((j = m->run_queue)) {
1038                 assert(j->installed);
1039                 assert(j->in_run_queue);
1040
1041                 job_run_and_invalidate(j);
1042         }
1043
1044         m->dispatching_run_queue = false;
1045 }
1046
1047 static int manager_dispatch_sigchld(Manager *m) {
1048         assert(m);
1049
1050         log_debug("dispatching SIGCHLD");
1051
1052         for (;;) {
1053                 siginfo_t si;
1054                 Unit *u;
1055
1056                 zero(si);
1057                 if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG) < 0) {
1058
1059                         if (errno == ECHILD)
1060                                 break;
1061
1062                         return -errno;
1063                 }
1064
1065                 if (si.si_pid == 0)
1066                         break;
1067
1068                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
1069                         continue;
1070
1071                 log_debug("child %llu died (code=%s, status=%i)", (long long unsigned) si.si_pid, sigchld_code_to_string(si.si_code), si.si_status);
1072
1073                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
1074                         continue;
1075
1076                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
1077         }
1078
1079         return 0;
1080 }
1081
1082 static int manager_process_signal_fd(Manager *m, bool *quit) {
1083         ssize_t n;
1084         struct signalfd_siginfo sfsi;
1085         bool sigchld = false;
1086
1087         assert(m);
1088
1089         for (;;) {
1090                 if ((n = read(m->signal_watch.fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
1091
1092                         if (n >= 0)
1093                                 return -EIO;
1094
1095                         if (errno == EAGAIN)
1096                                 break;
1097
1098                         return -errno;
1099                 }
1100
1101                 switch (sfsi.ssi_signo) {
1102
1103                 case SIGCHLD:
1104                         sigchld = true;
1105                         break;
1106
1107                 case SIGINT:
1108                 case SIGTERM:
1109                         *quit = true;
1110                         return 0;
1111
1112                 default:
1113                         log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));
1114                 }
1115         }
1116
1117         if (sigchld)
1118                 return manager_dispatch_sigchld(m);
1119
1120         return 0;
1121 }
1122
1123 static int process_event(Manager *m, struct epoll_event *ev, bool *quit) {
1124         int r;
1125         Watch *w;
1126
1127         assert(m);
1128         assert(ev);
1129
1130         assert(w = ev->data.ptr);
1131
1132         switch (w->type) {
1133
1134         case WATCH_SIGNAL:
1135
1136                 /* An incoming signal? */
1137                 if (ev->events != EPOLLIN)
1138                         return -EINVAL;
1139
1140                 if ((r = manager_process_signal_fd(m, quit)) < 0)
1141                         return r;
1142
1143                 break;
1144
1145         case WATCH_FD:
1146
1147                 /* Some fd event, to be dispatched to the units */
1148                 UNIT_VTABLE(w->data.unit)->fd_event(w->data.unit, w->fd, ev->events, w);
1149                 break;
1150
1151         case WATCH_TIMER: {
1152                 uint64_t v;
1153                 ssize_t k;
1154
1155                 /* Some timer event, to be dispatched to the units */
1156                 if ((k = read(ev->data.fd, &v, sizeof(v))) != sizeof(v)) {
1157
1158                         if (k < 0 && (errno == EINTR || errno == EAGAIN))
1159                                 break;
1160
1161                         return k < 0 ? -errno : -EIO;
1162                 }
1163
1164                 UNIT_VTABLE(w->data.unit)->timer_event(w->data.unit, v, w);
1165                 break;
1166         }
1167
1168         case WATCH_MOUNT:
1169                 /* Some mount table change, intended for the mount subsystem */
1170                 mount_fd_event(m, ev->events);
1171                 break;
1172
1173         case WATCH_UDEV:
1174                 /* Some notification from udev, intended for the device subsystem */
1175                 device_fd_event(m, ev->events);
1176                 break;
1177
1178         case WATCH_DBUS_WATCH:
1179                 bus_watch_event(m, w, ev->events);
1180                 break;
1181
1182         case WATCH_DBUS_TIMEOUT:
1183                 bus_timeout_event(m, w, ev->events);
1184                 break;
1185
1186         default:
1187                 assert_not_reached("Unknown epoll event type.");
1188         }
1189
1190         return 0;
1191 }
1192
1193 int manager_loop(Manager *m) {
1194         int r;
1195         bool quit = false;
1196
1197         RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 1000);
1198
1199         assert(m);
1200
1201         for (;;) {
1202                 struct epoll_event event;
1203                 int n;
1204
1205                 if (!ratelimit_test(&rl)) {
1206                         /* Yay, something is going seriously wrong, pause a little */
1207                         log_warning("Looping too fast. Throttling execution a little.");
1208                         sleep(1);
1209                 }
1210
1211                 manager_dispatch_run_queue(m);
1212
1213                 if (m->request_bus_dispatch) {
1214                         bus_dispatch(m);
1215                         continue;
1216                 }
1217
1218                 if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
1219
1220                         if (errno == -EINTR)
1221                                 continue;
1222
1223                         return -errno;
1224                 }
1225
1226                 assert(n == 1);
1227
1228                 if ((r = process_event(m, &event, &quit)) < 0)
1229                         return r;
1230
1231                 if (quit)
1232                         return 0;
1233         }
1234 }
1235
1236 int manager_get_unit_from_dbus_path(Manager *m, const char *s, Unit **_u) {
1237         char *n;
1238         Unit *u;
1239
1240         assert(m);
1241         assert(s);
1242         assert(_u);
1243
1244         if (!startswith(s, "/org/freedesktop/systemd1/unit/"))
1245                 return -EINVAL;
1246
1247         if (!(n = bus_path_unescape(s+31)))
1248                 return -ENOMEM;
1249
1250         u = manager_get_unit(m, n);
1251         free(n);
1252
1253         if (!u)
1254                 return -ENOENT;
1255
1256         *_u = u;
1257
1258         return 0;
1259 }