manager.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <assert.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <sys/epoll.h>
  26 #include <signal.h>
  27 #include <sys/signalfd.h>
  28 #include <sys/wait.h>
  29 #include <unistd.h>
  30 #include <sys/poll.h>
  31
  32 #include "manager.h"
  33 #include "hashmap.h"
  34 #include "macro.h"
  35 #include "strv.h"
  36 #include "log.h"
  37 #include "util.h"
  38 #include "ratelimit.h"
  39
  40 static int manager_setup_signals(Manager *m) {
  41         sigset_t mask;
  42         struct epoll_event ev;
  43
  44         assert(m);
  45
  46         assert_se(reset_all_signal_handlers() == 0);
  47
  48         assert_se(sigemptyset(&mask) == 0);
  49         assert_se(sigaddset(&mask, SIGCHLD) == 0);
  50         assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
  51         assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
  52         assert_se(sigaddset(&mask, SIGTERM) == 0);
  53         assert_se(sigaddset(&mask, SIGHUP) == 0);
  54         assert_se(sigaddset(&mask, SIGUSR1) == 0);
  55         assert_se(sigaddset(&mask, SIGUSR2) == 0);
  56         assert_se(sigaddset(&mask, SIGPIPE) == 0);
  57         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
  58
  59         m->signal_watch.type = WATCH_SIGNAL;
  60         if ((m->signal_watch.fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
  61                 return -errno;
  62
  63         zero(ev);
  64         ev.events = EPOLLIN;
  65         ev.data.ptr = &m->signal_watch;
  66
  67         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
  68                 return -errno;
  69
  70         return 0;
  71 }
  72
  73 Manager* manager_new(void) {
  74         Manager *m;
  75
  76         if (!(m = new0(Manager, 1)))
  77                 return NULL;
  78
  79         m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = -1;
  80         m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
  81
  82         if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
  83                 goto fail;
  84
  85         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  86                 goto fail;
  87
  88         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  89                 goto fail;
  90
  91         if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
  92                 goto fail;
  93
  94         if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
  95                 goto fail;
  96
  97         if (manager_setup_signals(m) < 0)
  98                 goto fail;
  99
 100         /* FIXME: this should be called only when the D-Bus bus daemon is running */
 101         if (bus_init(m) < 0)
 102                 goto fail;
 103
 104         return m;
 105
 106 fail:
 107         manager_free(m);
 108         return NULL;
 109 }
 110
 111 void manager_free(Manager *m) {
 112         UnitType c;
 113         Unit *u;
 114         Job *j;
 115
 116         assert(m);
 117
 118         while ((j = hashmap_first(m->transaction_jobs)))
 119                 job_free(j);
 120
 121         while ((u = hashmap_first(m->units)))
 122                 unit_free(u);
 123
 124         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 125                 if (unit_vtable[c]->shutdown)
 126                         unit_vtable[c]->shutdown(m);
 127
 128         bus_done(m);
 129
 130         hashmap_free(m->units);
 131         hashmap_free(m->jobs);
 132         hashmap_free(m->transaction_jobs);
 133         hashmap_free(m->watch_pids);
 134
 135         if (m->epoll_fd >= 0)
 136                 close_nointr(m->epoll_fd);
 137         if (m->signal_watch.fd >= 0)
 138                 close_nointr(m->signal_watch.fd);
 139
 140         free(m);
 141 }
 142
 143 int manager_coldplug(Manager *m) {
 144         int r;
 145         UnitType c;
 146         Iterator i;
 147         Unit *u;
 148         char *k;
 149
 150         assert(m);
 151
 152         /* First, let's ask every type to load all units from
 153          * disk/kernel that it might know */
 154         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 155                 if (unit_vtable[c]->enumerate)
 156                         if ((r = unit_vtable[c]->enumerate(m)) < 0)
 157                                 return r;
 158
 159         manager_dispatch_load_queue(m);
 160
 161         /* Then, let's set up their initial state. */
 162         HASHMAP_FOREACH_KEY(u, k, m->units, i) {
 163
 164                 /* ignore aliases */
 165                 if (unit_id(u) != k)
 166                         continue;
 167
 168                 if (UNIT_VTABLE(u)->coldplug)
 169                         if ((r = UNIT_VTABLE(u)->coldplug(u)) < 0)
 170                                 return r;
 171         }
 172
 173         return 0;
 174 }
 175
 176 static void transaction_delete_job(Manager *m, Job *j) {
 177         assert(m);
 178         assert(j);
 179
 180         /* Deletes one job from the transaction */
 181
 182         manager_transaction_unlink_job(m, j);
 183
 184         if (!j->installed)
 185                 job_free(j);
 186 }
 187
 188 static void transaction_delete_unit(Manager *m, Unit *u) {
 189         Job *j;
 190
 191         /* Deletes all jobs associated with a certain unit from the
 192          * transaction */
 193
 194         while ((j = hashmap_get(m->transaction_jobs, u)))
 195                 transaction_delete_job(m, j);
 196 }
 197
 198 static void transaction_clean_dependencies(Manager *m) {
 199         Iterator i;
 200         Job *j;
 201
 202         assert(m);
 203
 204         /* Drops all dependencies of all installed jobs */
 205
 206         HASHMAP_FOREACH(j, m->jobs, i) {
 207                 while (j->subject_list)
 208                         job_dependency_free(j->subject_list);
 209                 while (j->object_list)
 210                         job_dependency_free(j->object_list);
 211         }
 212
 213         assert(!m->transaction_anchor);
 214 }
 215
 216 static void transaction_abort(Manager *m) {
 217         Job *j;
 218
 219         assert(m);
 220
 221         while ((j = hashmap_first(m->transaction_jobs)))
 222                 if (j->installed)
 223                         transaction_delete_job(m, j);
 224                 else
 225                         job_free(j);
 226
 227         assert(hashmap_isempty(m->transaction_jobs));
 228
 229         transaction_clean_dependencies(m);
 230 }
 231
 232 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
 233         JobDependency *l;
 234
 235         assert(m);
 236
 237         /* A recursive sweep through the graph that marks all units
 238          * that matter to the anchor job, i.e. are directly or
 239          * indirectly a dependency of the anchor job via paths that
 240          * are fully marked as mattering. */
 241
 242         if (j)
 243                 l = j->subject_list;
 244         else
 245                 l = m->transaction_anchor;
 246
 247         LIST_FOREACH(subject, l, l) {
 248
 249                 /* This link does not matter */
 250                 if (!l->matters)
 251                         continue;
 252
 253                 /* This unit has already been marked */
 254                 if (l->object->generation == generation)
 255                         continue;
 256
 257                 l->object->matters_to_anchor = true;
 258                 l->object->generation = generation;
 259
 260                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
 261         }
 262 }
 263
 264 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 265         JobDependency *l, *last;
 266
 267         assert(j);
 268         assert(other);
 269         assert(j->unit == other->unit);
 270         assert(!j->installed);
 271
 272         /* Merges 'other' into 'j' and then deletes j. */
 273
 274         j->type = t;
 275         j->state = JOB_WAITING;
 276         j->forced = j->forced || other->forced;
 277
 278         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 279
 280         /* Patch us in as new owner of the JobDependency objects */
 281         last = NULL;
 282         LIST_FOREACH(subject, l, other->subject_list) {
 283                 assert(l->subject == other);
 284                 l->subject = j;
 285                 last = l;
 286         }
 287
 288         /* Merge both lists */
 289         if (last) {
 290                 last->subject_next = j->subject_list;
 291                 if (j->subject_list)
 292                         j->subject_list->subject_prev = last;
 293                 j->subject_list = other->subject_list;
 294         }
 295
 296         /* Patch us in as new owner of the JobDependency objects */
 297         last = NULL;
 298         LIST_FOREACH(object, l, other->object_list) {
 299                 assert(l->object == other);
 300                 l->object = j;
 301                 last = l;
 302         }
 303
 304         /* Merge both lists */
 305         if (last) {
 306                 last->object_next = j->object_list;
 307                 if (j->object_list)
 308                         j->object_list->object_prev = last;
 309                 j->object_list = other->object_list;
 310         }
 311
 312         /* Kill the other job */
 313         other->subject_list = NULL;
 314         other->object_list = NULL;
 315         transaction_delete_job(m, other);
 316 }
 317
 318 static int delete_one_unmergeable_job(Manager *m, Job *j) {
 319         Job *k;
 320
 321         assert(j);
 322
 323         /* Tries to delete one item in the linked list
 324          * j->transaction_next->transaction_next->... that conflicts
 325          * whith another one, in an attempt to make an inconsistent
 326          * transaction work. */
 327
 328         /* We rely here on the fact that if a merged with b does not
 329          * merge with c, either a or b merge with c neither */
 330         LIST_FOREACH(transaction, j, j)
 331                 LIST_FOREACH(transaction, k, j->transaction_next) {
 332                         Job *d;
 333
 334                         /* Is this one mergeable? Then skip it */
 335                         if (job_type_is_mergeable(j->type, k->type))
 336                                 continue;
 337
 338                         /* Ok, we found two that conflict, let's see if we can
 339                          * drop one of them */
 340                         if (!j->matters_to_anchor)
 341                                 d = j;
 342                         else if (!k->matters_to_anchor)
 343                                 d = k;
 344                         else
 345                                 return -ENOEXEC;
 346
 347                         /* Ok, we can drop one, so let's do so. */
 348                         log_debug("Try to fix job merging by deleting job %s/%s", unit_id(d->unit), job_type_to_string(d->type));
 349                         transaction_delete_job(m, d);
 350                         return 0;
 351                 }
 352
 353         return -EINVAL;
 354 }
 355
 356 static int transaction_merge_jobs(Manager *m) {
 357         Job *j;
 358         Iterator i;
 359         int r;
 360
 361         assert(m);
 362
 363         /* First step, check whether any of the jobs for one specific
 364          * task conflict. If so, try to drop one of them. */
 365         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 366                 JobType t;
 367                 Job *k;
 368
 369                 t = j->type;
 370                 LIST_FOREACH(transaction, k, j->transaction_next) {
 371                         if ((r = job_type_merge(&t, k->type)) >= 0)
 372                                 continue;
 373
 374                         /* OK, we could not merge all jobs for this
 375                          * action. Let's see if we can get rid of one
 376                          * of them */
 377
 378                         if ((r = delete_one_unmergeable_job(m, j)) >= 0)
 379                                 /* Ok, we managed to drop one, now
 380                                  * let's ask our callers to call us
 381                                  * again after garbage collecting */
 382                                 return -EAGAIN;
 383
 384                         /* We couldn't merge anything. Failure */
 385                         return r;
 386                 }
 387         }
 388
 389         /* Second step, merge the jobs. */
 390         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 391                 JobType t = j->type;
 392                 Job *k;
 393
 394                 /* Merge all transactions */
 395                 LIST_FOREACH(transaction, k, j->transaction_next)
 396                         assert_se(job_type_merge(&t, k->type) == 0);
 397
 398                 /* If an active job is mergeable, merge it too */
 399                 if (j->unit->meta.job)
 400                         job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
 401
 402                 while ((k = j->transaction_next)) {
 403                         if (j->installed) {
 404                                 transaction_merge_and_delete_job(m, k, j, t);
 405                                 j = k;
 406                         } else
 407                                 transaction_merge_and_delete_job(m, j, k, t);
 408                 }
 409
 410                 assert(!j->transaction_next);
 411                 assert(!j->transaction_prev);
 412         }
 413
 414         return 0;
 415 }
 416
 417 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 418         assert(u);
 419         assert(!j->transaction_prev);
 420
 421         /* Checks whether at least one of the jobs for this unit
 422          * matters to the anchor. */
 423
 424         LIST_FOREACH(transaction, j, j)
 425                 if (j->matters_to_anchor)
 426                         return true;
 427
 428         return false;
 429 }
 430
 431 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 432         Iterator i;
 433         Unit *u;
 434         int r;
 435
 436         assert(m);
 437         assert(j);
 438         assert(!j->transaction_prev);
 439
 440         /* Does a recursive sweep through the ordering graph, looking
 441          * for a cycle. If we find cycle we try to break it. */
 442
 443         /* Did we find a cycle? */
 444         if (j->marker && j->generation == generation) {
 445                 Job *k;
 446
 447                 /* So, we already have been here. We have a
 448                  * cycle. Let's try to break it. We go backwards in
 449                  * our path and try to find a suitable job to
 450                  * remove. We use the marker to find our way back,
 451                  * since smart how we are we stored our way back in
 452                  * there. */
 453
 454                 log_debug("Found cycle on %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 455
 456                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 457
 458                         log_debug("Walked on cycle path to %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 459
 460                         if (!k->installed &&
 461                             !unit_matters_to_anchor(k->unit, k)) {
 462                                 /* Ok, we can drop this one, so let's
 463                                  * do so. */
 464                                 log_debug("Breaking order cycle by deleting job %s/%s", unit_id(k->unit), job_type_to_string(k->type));
 465                                 transaction_delete_unit(m, k->unit);
 466                                 return -EAGAIN;
 467                         }
 468
 469                         /* Check if this in fact was the beginning of
 470                          * the cycle */
 471                         if (k == j)
 472                                 break;
 473                 }
 474
 475                 log_debug("Unable to break cycle");
 476
 477                 return -ENOEXEC;
 478         }
 479
 480         /* Make the marker point to where we come from, so that we can
 481          * find our way backwards if we want to break a cycle */
 482         j->marker = from;
 483         j->generation = generation;
 484
 485         /* We assume that the the dependencies are bidirectional, and
 486          * hence can ignore UNIT_AFTER */
 487         SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
 488                 Job *o;
 489
 490                 /* Is there a job for this unit? */
 491                 if (!(o = hashmap_get(m->transaction_jobs, u)))
 492
 493                         /* Ok, there is no job for this in the
 494                          * transaction, but maybe there is already one
 495                          * running? */
 496                         if (!(o = u->meta.job))
 497                                 continue;
 498
 499                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 500                         return r;
 501         }
 502
 503         /* Ok, let's backtrack, and remember that this entry is not on
 504          * our path anymore. */
 505         j->marker = NULL;
 506
 507         return 0;
 508 }
 509
 510 static int transaction_verify_order(Manager *m, unsigned *generation) {
 511         Job *j;
 512         int r;
 513         Iterator i;
 514
 515         assert(m);
 516         assert(generation);
 517
 518         /* Check if the ordering graph is cyclic. If it is, try to fix
 519          * that up by dropping one of the jobs. */
 520
 521         HASHMAP_FOREACH(j, m->transaction_jobs, i)
 522                 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
 523                         return r;
 524
 525         return 0;
 526 }
 527
 528 static void transaction_collect_garbage(Manager *m) {
 529         bool again;
 530
 531         assert(m);
 532
 533         /* Drop jobs that are not required by any other job */
 534
 535         do {
 536                 Iterator i;
 537                 Job *j;
 538
 539                 again = false;
 540
 541                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 542                         if (j->object_list)
 543                                 continue;
 544
 545                         log_debug("Garbage collecting job %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 546                         transaction_delete_job(m, j);
 547                         again = true;
 548                         break;
 549                 }
 550
 551         } while (again);
 552 }
 553
 554 static int transaction_is_destructive(Manager *m, JobMode mode) {
 555         Iterator i;
 556         Job *j;
 557
 558         assert(m);
 559
 560         /* Checks whether applying this transaction means that
 561          * existing jobs would be replaced */
 562
 563         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 564
 565                 /* Assume merged */
 566                 assert(!j->transaction_prev);
 567                 assert(!j->transaction_next);
 568
 569                 if (j->unit->meta.job &&
 570                     j->unit->meta.job != j &&
 571                     !job_type_is_superset(j->type, j->unit->meta.job->type))
 572                         return -EEXIST;
 573         }
 574
 575         return 0;
 576 }
 577
 578 static void transaction_minimize_impact(Manager *m) {
 579         bool again;
 580         assert(m);
 581
 582         /* Drops all unnecessary jobs that reverse already active jobs
 583          * or that stop a running service. */
 584
 585         do {
 586                 Job *j;
 587                 Iterator i;
 588
 589                 again = false;
 590
 591                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 592                         LIST_FOREACH(transaction, j, j) {
 593                                 bool stops_running_service, changes_existing_job;
 594
 595                                 /* If it matters, we shouldn't drop it */
 596                                 if (j->matters_to_anchor)
 597                                         continue;
 598
 599                                 /* Would this stop a running service?
 600                                  * Would this change an existing job?
 601                                  * If so, let's drop this entry */
 602
 603                                 stops_running_service =
 604                                         j->type == JOB_STOP && UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(j->unit));
 605
 606                                 changes_existing_job =
 607                                         j->unit->meta.job && job_type_is_conflicting(j->type, j->unit->meta.job->state);
 608
 609                                 if (!stops_running_service && !changes_existing_job)
 610                                         continue;
 611
 612                                 if (stops_running_service)
 613                                         log_debug("%s/%s would stop a running service.", unit_id(j->unit), job_type_to_string(j->type));
 614
 615                                 if (changes_existing_job)
 616                                         log_debug("%s/%s would change existing job.", unit_id(j->unit), job_type_to_string(j->type));
 617
 618                                 /* Ok, let's get rid of this */
 619                                 log_debug("Deleting %s/%s to minimize impact.", unit_id(j->unit), job_type_to_string(j->type));
 620
 621                                 transaction_delete_job(m, j);
 622                                 again = true;
 623                                 break;
 624                         }
 625
 626                         if (again)
 627                                 break;
 628                 }
 629
 630         } while (again);
 631 }
 632
 633 static int transaction_apply(Manager *m, JobMode mode) {
 634         Iterator i;
 635         Job *j;
 636         int r;
 637
 638         /* Moves the transaction jobs to the set of active jobs */
 639
 640         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 641                 /* Assume merged */
 642                 assert(!j->transaction_prev);
 643                 assert(!j->transaction_next);
 644
 645                 if (j->installed)
 646                         continue;
 647
 648                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 649                         goto rollback;
 650         }
 651
 652         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 653                 if (j->installed)
 654                         continue;
 655
 656                 if (j->unit->meta.job)
 657                         job_free(j->unit->meta.job);
 658
 659                 j->unit->meta.job = j;
 660                 j->installed = true;
 661
 662                 /* We're fully installed. Now let's free data we don't
 663                  * need anymore. */
 664
 665                 assert(!j->transaction_next);
 666                 assert(!j->transaction_prev);
 667
 668                 job_add_to_run_queue(j);
 669                 job_add_to_dbus_queue(j);
 670         }
 671
 672         /* As last step, kill all remaining job dependencies. */
 673         transaction_clean_dependencies(m);
 674
 675         return 0;
 676
 677 rollback:
 678
 679         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 680                 if (j->installed)
 681                         continue;
 682
 683                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 684         }
 685
 686         return r;
 687 }
 688
 689 static int transaction_activate(Manager *m, JobMode mode) {
 690         int r;
 691         unsigned generation = 1;
 692
 693         assert(m);
 694
 695         /* This applies the changes recorded in transaction_jobs to
 696          * the actual list of jobs, if possible. */
 697
 698         /* First step: figure out which jobs matter */
 699         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 700
 701         /* Second step: Try not to stop any running services if
 702          * we don't have to. Don't try to reverse running
 703          * jobs if we don't have to. */
 704         transaction_minimize_impact(m);
 705
 706         for (;;) {
 707                 /* Third step: Let's remove unneeded jobs that might
 708                  * be lurking. */
 709                 transaction_collect_garbage(m);
 710
 711                 /* Fourth step: verify order makes sense and correct
 712                  * cycles if necessary and possible */
 713                 if ((r = transaction_verify_order(m, &generation)) >= 0)
 714                         break;
 715
 716                 if (r != -EAGAIN) {
 717                         log_debug("Requested transaction contains an unfixable cyclic ordering dependency: %s", strerror(-r));
 718                         goto rollback;
 719                 }
 720
 721                 /* Let's see if the resulting transaction ordering
 722                  * graph is still cyclic... */
 723         }
 724
 725         for (;;) {
 726                 /* Fifth step: let's drop unmergeable entries if
 727                  * necessary and possible, merge entries we can
 728                  * merge */
 729                 if ((r = transaction_merge_jobs(m)) >= 0)
 730                         break;
 731
 732                 if (r != -EAGAIN) {
 733                         log_debug("Requested transaction contains unmergable jobs: %s", strerror(-r));
 734                         goto rollback;
 735                 }
 736
 737                 /* Sixth step: an entry got dropped, let's garbage
 738                  * collect its dependencies. */
 739                 transaction_collect_garbage(m);
 740
 741                 /* Let's see if the resulting transaction still has
 742                  * unmergeable entries ... */
 743         }
 744
 745         /* Seventh step: check whether we can actually apply this */
 746         if (mode == JOB_FAIL)
 747                 if ((r = transaction_is_destructive(m, mode)) < 0) {
 748                         log_debug("Requested transaction contradicts existing jobs: %s", strerror(-r));
 749                         goto rollback;
 750                 }
 751
 752         /* Eights step: apply changes */
 753         if ((r = transaction_apply(m, mode)) < 0) {
 754                 log_debug("Failed to apply transaction: %s", strerror(-r));
 755                 goto rollback;
 756         }
 757
 758         assert(hashmap_isempty(m->transaction_jobs));
 759         assert(!m->transaction_anchor);
 760
 761         return 0;
 762
 763 rollback:
 764         transaction_abort(m);
 765         return r;
 766 }
 767
 768 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool force, bool *is_new) {
 769         Job *j, *f;
 770         int r;
 771
 772         assert(m);
 773         assert(unit);
 774
 775         /* Looks for an axisting prospective job and returns that. If
 776          * it doesn't exist it is created and added to the prospective
 777          * jobs list. */
 778
 779         f = hashmap_get(m->transaction_jobs, unit);
 780
 781         LIST_FOREACH(transaction, j, f) {
 782                 assert(j->unit == unit);
 783
 784                 if (j->type == type) {
 785                         if (is_new)
 786                                 *is_new = false;
 787                         return j;
 788                 }
 789         }
 790
 791         if (unit->meta.job && unit->meta.job->type == type)
 792                 j = unit->meta.job;
 793         else if (!(j = job_new(m, type, unit)))
 794                 return NULL;
 795
 796         j->generation = 0;
 797         j->marker = NULL;
 798         j->matters_to_anchor = false;
 799         j->forced = force;
 800
 801         LIST_PREPEND(Job, transaction, f, j);
 802
 803         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
 804                 job_free(j);
 805                 return NULL;
 806         }
 807
 808         if (is_new)
 809                 *is_new = true;
 810
 811         return j;
 812 }
 813
 814 void manager_transaction_unlink_job(Manager *m, Job *j) {
 815         assert(m);
 816         assert(j);
 817
 818         if (j->transaction_prev)
 819                 j->transaction_prev->transaction_next = j->transaction_next;
 820         else if (j->transaction_next)
 821                 hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
 822         else
 823                 hashmap_remove_value(m->transaction_jobs, j->unit, j);
 824
 825         if (j->transaction_next)
 826                 j->transaction_next->transaction_prev = j->transaction_prev;
 827
 828         j->transaction_prev = j->transaction_next = NULL;
 829
 830         while (j->subject_list)
 831                 job_dependency_free(j->subject_list);
 832
 833         while (j->object_list) {
 834                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 835
 836                 job_dependency_free(j->object_list);
 837
 838                 if (other) {
 839                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
 840                                   unit_id(other->unit), job_type_to_string(other->type),
 841                                   unit_id(j->unit), job_type_to_string(j->type));
 842                         transaction_delete_job(m, other);
 843                 }
 844         }
 845 }
 846
 847 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Unit *unit, Job *by, bool matters, bool force, Job **_ret) {
 848         Job *ret;
 849         Iterator i;
 850         Unit *dep;
 851         int r;
 852         bool is_new;
 853
 854         assert(m);
 855         assert(type < _JOB_TYPE_MAX);
 856         assert(unit);
 857
 858         if (unit->meta.load_state != UNIT_LOADED)
 859                 return -EINVAL;
 860
 861         if (!unit_job_is_applicable(unit, type))
 862                 return -EBADR;
 863
 864         /* First add the job. */
 865         if (!(ret = transaction_add_one_job(m, type, unit, force, &is_new)))
 866                 return -ENOMEM;
 867
 868         /* Then, add a link to the job. */
 869         if (!job_dependency_new(by, ret, matters))
 870                 return -ENOMEM;
 871
 872         if (is_new) {
 873                 /* Finally, recursively add in all dependencies. */
 874                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 875                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
 876                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 877                                         goto fail;
 878                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 879                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 880                                         goto fail;
 881                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
 882                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR)
 883                                         goto fail;
 884                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
 885                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 886                                         goto fail;
 887                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUISITE], i)
 888                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
 889                                         goto fail;
 890                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
 891                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 892                                         goto fail;
 893
 894                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 895
 896                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
 897                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
 898                                         goto fail;
 899                 }
 900
 901                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 902         }
 903
 904         return 0;
 905
 906 fail:
 907         return r;
 908 }
 909
 910 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool force, Job **_ret) {
 911         int r;
 912         Job *ret;
 913
 914         assert(m);
 915         assert(type < _JOB_TYPE_MAX);
 916         assert(unit);
 917         assert(mode < _JOB_MODE_MAX);
 918
 919         log_debug("Trying to enqueue job %s/%s", unit_id(unit), job_type_to_string(type));
 920
 921         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, force, &ret))) {
 922                 transaction_abort(m);
 923                 return r;
 924         }
 925
 926         if ((r = transaction_activate(m, mode)) < 0)
 927                 return r;
 928
 929         log_debug("Enqueued job %s/%s", unit_id(unit), job_type_to_string(type));
 930
 931         if (_ret)
 932                 *_ret = ret;
 933
 934         return 0;
 935 }
 936
 937 Job *manager_get_job(Manager *m, uint32_t id) {
 938         assert(m);
 939
 940         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 941 }
 942
 943 Unit *manager_get_unit(Manager *m, const char *name) {
 944         assert(m);
 945         assert(name);
 946
 947         return hashmap_get(m->units, name);
 948 }
 949
 950 unsigned manager_dispatch_load_queue(Manager *m) {
 951         Meta *meta;
 952         unsigned n = 0;
 953
 954         assert(m);
 955
 956         /* Make sure we are not run recursively */
 957         if (m->dispatching_load_queue)
 958                 return 0;
 959
 960         m->dispatching_load_queue = true;
 961
 962         /* Dispatches the load queue. Takes a unit from the queue and
 963          * tries to load its data until the queue is empty */
 964
 965         while ((meta = m->load_queue)) {
 966                 assert(meta->in_load_queue);
 967
 968                 unit_load(UNIT(meta));
 969                 n++;
 970         }
 971
 972         m->dispatching_load_queue = false;
 973         return n;
 974 }
 975
 976 int manager_load_unit(Manager *m, const char *path, Unit **_ret) {
 977         Unit *ret;
 978         int r;
 979         const char *name;
 980
 981         assert(m);
 982         assert(path);
 983         assert(_ret);
 984
 985         /* This will load the service information files, but not actually
 986          * start any services or anything. */
 987
 988         name = file_name_from_path(path);
 989
 990         if ((ret = manager_get_unit(m, name))) {
 991                 *_ret = ret;
 992                 return 0;
 993         }
 994
 995         if (!(ret = unit_new(m)))
 996                 return -ENOMEM;
 997
 998         if (is_path(path)) {
 999                 if (!(ret->meta.load_path = strdup(path))) {
1000                         unit_free(ret);
1001                         return -ENOMEM;
1002                 }
1003         }
1004
1005         if ((r = unit_add_name(ret, name)) < 0) {
1006                 unit_free(ret);
1007                 return r;
1008         }
1009
1010         unit_add_to_load_queue(ret);
1011         unit_add_to_dbus_queue(ret);
1012
1013         manager_dispatch_load_queue(m);
1014
1015         *_ret = ret;
1016         return 0;
1017 }
1018
1019 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
1020         Iterator i;
1021         Job *j;
1022
1023         assert(s);
1024         assert(f);
1025
1026         HASHMAP_FOREACH(j, s->jobs, i)
1027                 job_dump(j, f, prefix);
1028 }
1029
1030 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
1031         Iterator i;
1032         Unit *u;
1033         const char *t;
1034
1035         assert(s);
1036         assert(f);
1037
1038         HASHMAP_FOREACH_KEY(u, t, s->units, i)
1039                 if (unit_id(u) == t)
1040                         unit_dump(u, f, prefix);
1041 }
1042
1043 void manager_clear_jobs(Manager *m) {
1044         Job *j;
1045
1046         assert(m);
1047
1048         transaction_abort(m);
1049
1050         while ((j = hashmap_first(m->jobs)))
1051                 job_free(j);
1052 }
1053
1054 unsigned manager_dispatch_run_queue(Manager *m) {
1055         Job *j;
1056         unsigned n = 0;
1057
1058         if (m->dispatching_run_queue)
1059                 return 0;
1060
1061         m->dispatching_run_queue = true;
1062
1063         while ((j = m->run_queue)) {
1064                 assert(j->installed);
1065                 assert(j->in_run_queue);
1066
1067                 job_run_and_invalidate(j);
1068                 n++;
1069         }
1070
1071         m->dispatching_run_queue = false;
1072         return n;
1073 }
1074
1075 unsigned manager_dispatch_dbus_queue(Manager *m) {
1076         Job *j;
1077         Meta *meta;
1078         unsigned n = 0;
1079
1080         assert(m);
1081
1082         if (m->dispatching_dbus_queue)
1083                 return 0;
1084
1085         m->dispatching_dbus_queue = true;
1086
1087         while ((meta = m->dbus_unit_queue)) {
1088                 Unit *u = (Unit*) meta;
1089                 assert(u->meta.in_dbus_queue);
1090
1091                 bus_unit_send_change_signal(u);
1092                 n++;
1093         }
1094
1095         while ((j = m->dbus_job_queue)) {
1096                 assert(j->in_dbus_queue);
1097
1098                 bus_job_send_change_signal(j);
1099                 n++;
1100         }
1101
1102         m->dispatching_dbus_queue = false;
1103         return n;
1104 }
1105
1106 static int manager_dispatch_sigchld(Manager *m) {
1107         assert(m);
1108
1109         log_debug("dispatching SIGCHLD");
1110
1111         for (;;) {
1112                 siginfo_t si;
1113                 Unit *u;
1114
1115                 zero(si);
1116                 if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG) < 0) {
1117
1118                         if (errno == ECHILD)
1119                                 break;
1120
1121                         return -errno;
1122                 }
1123
1124                 if (si.si_pid == 0)
1125                         break;
1126
1127                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
1128                         continue;
1129
1130                 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);
1131
1132                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
1133                         continue;
1134
1135                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
1136         }
1137
1138         return 0;
1139 }
1140
1141 static int manager_process_signal_fd(Manager *m, bool *quit) {
1142         ssize_t n;
1143         struct signalfd_siginfo sfsi;
1144         bool sigchld = false;
1145
1146         assert(m);
1147
1148         for (;;) {
1149                 if ((n = read(m->signal_watch.fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
1150
1151                         if (n >= 0)
1152                                 return -EIO;
1153
1154                         if (errno == EAGAIN)
1155                                 break;
1156
1157                         return -errno;
1158                 }
1159
1160                 switch (sfsi.ssi_signo) {
1161
1162                 case SIGCHLD:
1163                         sigchld = true;
1164                         break;
1165
1166                 case SIGINT:
1167                 case SIGTERM:
1168                         *quit = true;
1169                         return 0;
1170
1171                 default:
1172                         log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));
1173                 }
1174         }
1175
1176         if (sigchld)
1177                 return manager_dispatch_sigchld(m);
1178
1179         return 0;
1180 }
1181
1182 static int process_event(Manager *m, struct epoll_event *ev, bool *quit) {
1183         int r;
1184         Watch *w;
1185
1186         assert(m);
1187         assert(ev);
1188
1189         assert(w = ev->data.ptr);
1190
1191         switch (w->type) {
1192
1193         case WATCH_SIGNAL:
1194
1195                 /* An incoming signal? */
1196                 if (ev->events != EPOLLIN)
1197                         return -EINVAL;
1198
1199                 if ((r = manager_process_signal_fd(m, quit)) < 0)
1200                         return r;
1201
1202                 break;
1203
1204         case WATCH_FD:
1205
1206                 /* Some fd event, to be dispatched to the units */
1207                 UNIT_VTABLE(w->data.unit)->fd_event(w->data.unit, w->fd, ev->events, w);
1208                 break;
1209
1210         case WATCH_TIMER: {
1211                 uint64_t v;
1212                 ssize_t k;
1213
1214                 /* Some timer event, to be dispatched to the units */
1215                 if ((k = read(ev->data.fd, &v, sizeof(v))) != sizeof(v)) {
1216
1217                         if (k < 0 && (errno == EINTR || errno == EAGAIN))
1218                                 break;
1219
1220                         return k < 0 ? -errno : -EIO;
1221                 }
1222
1223                 UNIT_VTABLE(w->data.unit)->timer_event(w->data.unit, v, w);
1224                 break;
1225         }
1226
1227         case WATCH_MOUNT:
1228                 /* Some mount table change, intended for the mount subsystem */
1229                 mount_fd_event(m, ev->events);
1230                 break;
1231
1232         case WATCH_UDEV:
1233                 /* Some notification from udev, intended for the device subsystem */
1234                 device_fd_event(m, ev->events);
1235                 break;
1236
1237         case WATCH_DBUS_WATCH:
1238                 bus_watch_event(m, w, ev->events);
1239                 break;
1240
1241         case WATCH_DBUS_TIMEOUT:
1242                 bus_timeout_event(m, w, ev->events);
1243                 break;
1244
1245         default:
1246                 assert_not_reached("Unknown epoll event type.");
1247         }
1248
1249         return 0;
1250 }
1251
1252 int manager_loop(Manager *m) {
1253         int r;
1254         bool quit = false;
1255
1256         RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 1000);
1257
1258         assert(m);
1259
1260         for (;;) {
1261                 struct epoll_event event;
1262                 int n;
1263
1264                 if (!ratelimit_test(&rl)) {
1265                         /* Yay, something is going seriously wrong, pause a little */
1266                         log_warning("Looping too fast. Throttling execution a little.");
1267                         sleep(1);
1268                 }
1269
1270                 if (manager_dispatch_load_queue(m) > 0)
1271                         continue;
1272
1273                 if (manager_dispatch_run_queue(m) > 0)
1274                         continue;
1275
1276                 if (bus_dispatch(m) > 0)
1277                         continue;
1278
1279                 if (manager_dispatch_dbus_queue(m) > 0)
1280                         continue;
1281
1282                 if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
1283
1284                         if (errno == -EINTR)
1285                                 continue;
1286
1287                         return -errno;
1288                 }
1289
1290                 assert(n == 1);
1291
1292                 if ((r = process_event(m, &event, &quit)) < 0)
1293                         return r;
1294
1295                 if (quit)
1296                         return 0;
1297         }
1298 }
1299
1300 int manager_get_unit_from_dbus_path(Manager *m, const char *s, Unit **_u) {
1301         char *n;
1302         Unit *u;
1303
1304         assert(m);
1305         assert(s);
1306         assert(_u);
1307
1308         if (!startswith(s, "/org/freedesktop/systemd1/unit/"))
1309                 return -EINVAL;
1310
1311         if (!(n = bus_path_unescape(s+31)))
1312                 return -ENOMEM;
1313
1314         u = manager_get_unit(m, n);
1315         free(n);
1316
1317         if (!u)
1318                 return -ENOENT;
1319
1320         *_u = u;
1321
1322         return 0;
1323 }
1324
1325 int manager_get_job_from_dbus_path(Manager *m, const char *s, Job **_j) {
1326         Job *j;
1327         unsigned id;
1328         int r;
1329
1330         assert(m);
1331         assert(s);
1332         assert(_j);
1333
1334         if (!startswith(s, "/org/freedesktop/systemd1/job/"))
1335                 return -EINVAL;
1336
1337         if ((r = safe_atou(s + 30, &id)) < 0)
1338                 return r;
1339
1340         if (!(j = manager_get_job(m, id)))
1341                 return -ENOENT;
1342
1343         *_j = j;
1344
1345         return 0;
1346 }