unit.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 <sys/timerfd.h>
   8 #include <sys/poll.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11
  12 #include "set.h"
  13 #include "unit.h"
  14 #include "macro.h"
  15 #include "strv.h"
  16 #include "load-fragment.h"
  17 #include "load-dropin.h"
  18 #include "log.h"
  19
  20 const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX] = {
  21         [UNIT_SERVICE] = &service_vtable,
  22         [UNIT_TIMER] = &timer_vtable,
  23         [UNIT_SOCKET] = &socket_vtable,
  24         [UNIT_TARGET] = &target_vtable,
  25         [UNIT_DEVICE] = &device_vtable,
  26         [UNIT_MOUNT] = &mount_vtable,
  27         [UNIT_AUTOMOUNT] = &automount_vtable,
  28         [UNIT_SNAPSHOT] = &snapshot_vtable
  29 };
  30
  31 UnitType unit_name_to_type(const char *n) {
  32         UnitType t;
  33
  34         assert(n);
  35
  36         for (t = 0; t < _UNIT_TYPE_MAX; t++)
  37                 if (endswith(n, unit_vtable[t]->suffix))
  38                         return t;
  39
  40         return _UNIT_TYPE_INVALID;
  41 }
  42
  43 #define VALID_CHARS                             \
  44         "0123456789"                            \
  45         "abcdefghijklmnopqrstuvwxyz"            \
  46         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"            \
  47         "-_"
  48
  49 bool unit_name_is_valid(const char *n) {
  50         UnitType t;
  51         const char *e, *i;
  52
  53         assert(n);
  54
  55         if (strlen(n) >= UNIT_NAME_MAX)
  56                 return false;
  57
  58         t = unit_name_to_type(n);
  59         if (t < 0 || t >= _UNIT_TYPE_MAX)
  60                 return false;
  61
  62         if (!(e = strrchr(n, '.')))
  63                 return false;
  64
  65         for (i = n; i < e; i++)
  66                 if (!strchr(VALID_CHARS, *i))
  67                         return false;
  68
  69         return true;
  70 }
  71
  72 char *unit_name_change_suffix(const char *n, const char *suffix) {
  73         char *e, *r;
  74         size_t a, b;
  75
  76         assert(n);
  77         assert(unit_name_is_valid(n));
  78         assert(suffix);
  79
  80         assert_se(e = strrchr(n, '.'));
  81         a = e - n;
  82         b = strlen(suffix);
  83
  84         if (!(r = new(char, a + b + 1)))
  85                 return NULL;
  86
  87         memcpy(r, n, a);
  88         memcpy(r+a, suffix, b+1);
  89
  90         return r;
  91 }
  92
  93 Unit *unit_new(Manager *m) {
  94         Unit *u;
  95
  96         assert(m);
  97
  98         if (!(u = new0(Unit, 1)))
  99                 return NULL;
 100
 101         if (!(u->meta.names = set_new(string_hash_func, string_compare_func))) {
 102                 free(u);
 103                 return NULL;
 104         }
 105
 106         u->meta.manager = m;
 107         u->meta.type = _UNIT_TYPE_INVALID;
 108
 109         return u;
 110 }
 111
 112 int unit_add_name(Unit *u, const char *text) {
 113         UnitType t;
 114         char *s;
 115         int r;
 116
 117         assert(u);
 118         assert(text);
 119
 120         if (!unit_name_is_valid(text))
 121                 return -EINVAL;
 122
 123         if ((t = unit_name_to_type(text)) == _UNIT_TYPE_INVALID)
 124                 return -EINVAL;
 125
 126         if (u->meta.type != _UNIT_TYPE_INVALID && t != u->meta.type)
 127                 return -EINVAL;
 128
 129         if (!(s = strdup(text)))
 130                 return -ENOMEM;
 131
 132         if ((r = set_put(u->meta.names, s)) < 0) {
 133                 free(s);
 134
 135                 if (r == -EEXIST)
 136                         return 0;
 137
 138                 return r;
 139         }
 140
 141         if ((r = hashmap_put(u->meta.manager->units, s, u)) < 0) {
 142                 set_remove(u->meta.names, s);
 143                 free(s);
 144                 return r;
 145         }
 146
 147         u->meta.type = t;
 148
 149         if (!u->meta.id)
 150                 u->meta.id = s;
 151
 152         return 0;
 153 }
 154
 155 void unit_add_to_load_queue(Unit *u) {
 156         assert(u);
 157
 158         if (u->meta.load_state != UNIT_STUB || u->meta.in_load_queue)
 159                 return;
 160
 161         LIST_PREPEND(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
 162         u->meta.in_load_queue = true;
 163 }
 164
 165 static void bidi_set_free(Unit *u, Set *s) {
 166         Iterator i;
 167         Unit *other;
 168
 169         assert(u);
 170
 171         /* Frees the set and makes sure we are dropped from the
 172          * inverse pointers */
 173
 174         SET_FOREACH(other, s, i) {
 175                 UnitDependency d;
 176
 177                 for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
 178                         set_remove(other->meta.dependencies[d], u);
 179         }
 180
 181         set_free(s);
 182 }
 183
 184 void unit_free(Unit *u) {
 185         UnitDependency d;
 186         Iterator i;
 187         char *t;
 188
 189         assert(u);
 190
 191         /* Detach from next 'bigger' objects */
 192
 193         SET_FOREACH(t, u->meta.names, i)
 194                 hashmap_remove_value(u->meta.manager->units, t, u);
 195
 196         if (u->meta.in_load_queue)
 197                 LIST_REMOVE(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
 198
 199         if (u->meta.load_state == UNIT_LOADED)
 200                 if (UNIT_VTABLE(u)->done)
 201                         UNIT_VTABLE(u)->done(u);
 202
 203         /* Free data and next 'smaller' objects */
 204         if (u->meta.job)
 205                 job_free(u->meta.job);
 206
 207         for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
 208                 bidi_set_free(u, u->meta.dependencies[d]);
 209
 210         free(u->meta.description);
 211         free(u->meta.load_path);
 212
 213         while ((t = set_steal_first(u->meta.names)))
 214                 free(t);
 215         set_free(u->meta.names);
 216
 217         free(u);
 218 }
 219
 220 UnitActiveState unit_active_state(Unit *u) {
 221         assert(u);
 222
 223         if (u->meta.load_state != UNIT_LOADED)
 224                 return UNIT_INACTIVE;
 225
 226         return UNIT_VTABLE(u)->active_state(u);
 227 }
 228
 229 static int ensure_merge(Set **s, Set *other) {
 230
 231         if (!other)
 232                 return 0;
 233
 234         if (*s)
 235                 return set_merge(*s, other);
 236
 237         if (!(*s = set_copy(other)))
 238                 return -ENOMEM;
 239
 240         return 0;
 241 }
 242
 243 /* FIXME: Does not rollback on failure! */
 244 int unit_merge(Unit *u, Unit *other) {
 245         int r;
 246         UnitDependency d;
 247
 248         assert(u);
 249         assert(other);
 250         assert(u->meta.manager == other->meta.manager);
 251
 252         /* This merges 'other' into 'unit'. FIXME: This does not
 253          * rollback on failure. */
 254
 255         if (u->meta.type != u->meta.type)
 256                 return -EINVAL;
 257
 258         if (u->meta.load_state != UNIT_STUB)
 259                 return -EINVAL;
 260
 261         /* Merge names */
 262         if ((r = ensure_merge(&u->meta.names, other->meta.names)) < 0)
 263                 return r;
 264
 265         /* Merge dependencies */
 266         for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
 267                 /* fixme, the inverse mapping is missing */
 268                 if ((r = ensure_merge(&u->meta.dependencies[d], other->meta.dependencies[d])) < 0)
 269                         return r;
 270
 271         return 0;
 272 }
 273
 274 const char* unit_id(Unit *u) {
 275         assert(u);
 276
 277         if (u->meta.id)
 278                 return u->meta.id;
 279
 280         return set_first(u->meta.names);
 281 }
 282
 283 const char *unit_description(Unit *u) {
 284         assert(u);
 285
 286         if (u->meta.description)
 287                 return u->meta.description;
 288
 289         return unit_id(u);
 290 }
 291
 292 void unit_dump(Unit *u, FILE *f, const char *prefix) {
 293
 294         static const char* const load_state_table[_UNIT_LOAD_STATE_MAX] = {
 295                 [UNIT_STUB] = "stub",
 296                 [UNIT_LOADED] = "loaded",
 297                 [UNIT_FAILED] = "failed"
 298         };
 299
 300         static const char* const active_state_table[_UNIT_ACTIVE_STATE_MAX] = {
 301                 [UNIT_ACTIVE] = "active",
 302                 [UNIT_INACTIVE] = "inactive",
 303                 [UNIT_ACTIVATING] = "activating",
 304                 [UNIT_DEACTIVATING] = "deactivating"
 305         };
 306
 307         static const char* const dependency_table[_UNIT_DEPENDENCY_MAX] = {
 308                 [UNIT_REQUIRES] = "Requires",
 309                 [UNIT_SOFT_REQUIRES] = "SoftRequires",
 310                 [UNIT_WANTS] = "Wants",
 311                 [UNIT_REQUISITE] = "Requisite",
 312                 [UNIT_SOFT_REQUISITE] = "SoftRequisite",
 313                 [UNIT_REQUIRED_BY] = "RequiredBy",
 314                 [UNIT_SOFT_REQUIRED_BY] = "SoftRequiredBy",
 315                 [UNIT_WANTED_BY] = "WantedBy",
 316                 [UNIT_CONFLICTS] = "Conflicts",
 317                 [UNIT_BEFORE] = "Before",
 318                 [UNIT_AFTER] = "After",
 319         };
 320
 321         char *t;
 322         UnitDependency d;
 323         Iterator i;
 324         char *prefix2;
 325
 326         assert(u);
 327
 328         if (!prefix)
 329                 prefix = "";
 330         prefix2 = strappend(prefix, "\t");
 331         if (!prefix2)
 332                 prefix2 = "";
 333
 334         fprintf(f,
 335                 "%s→ Unit %s:\n"
 336                 "%s\tDescription: %s\n"
 337                 "%s\tUnit Load State: %s\n"
 338                 "%s\tUnit Active State: %s\n",
 339                 prefix, unit_id(u),
 340                 prefix, unit_description(u),
 341                 prefix, load_state_table[u->meta.load_state],
 342                 prefix, active_state_table[unit_active_state(u)]);
 343
 344         if (u->meta.load_path)
 345                 fprintf(f, "%s\tLoad Path: %s\n", prefix, u->meta.load_path);
 346
 347         SET_FOREACH(t, u->meta.names, i)
 348                 fprintf(f, "%s\tName: %s\n", prefix, t);
 349
 350         for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++) {
 351                 Unit *other;
 352
 353                 if (set_isempty(u->meta.dependencies[d]))
 354                         continue;
 355
 356                 SET_FOREACH(other, u->meta.dependencies[d], i)
 357                         fprintf(f, "%s\t%s: %s\n", prefix, dependency_table[d], unit_id(other));
 358         }
 359
 360         if (UNIT_VTABLE(u)->dump)
 361                 UNIT_VTABLE(u)->dump(u, f, prefix2);
 362
 363         if (u->meta.job)
 364                 job_dump(u->meta.job, f, prefix2);
 365
 366         free(prefix2);
 367 }
 368
 369 /* Common implementation for multiple backends */
 370 int unit_load_fragment_and_dropin(Unit *u) {
 371         int r;
 372
 373         assert(u);
 374
 375         /* Load a .socket file */
 376         if ((r = unit_load_fragment(u)) < 0)
 377                 return r;
 378
 379         /* Load drop-in directory data */
 380         if ((r = unit_load_dropin(u)) < 0)
 381                 return r;
 382
 383         return 0;
 384 }
 385
 386 int unit_load(Unit *u) {
 387         int r;
 388
 389         assert(u);
 390
 391         if (u->meta.in_load_queue) {
 392                 LIST_REMOVE(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
 393                 u->meta.in_load_queue = false;
 394         }
 395
 396         if (u->meta.load_state != UNIT_STUB)
 397                 return 0;
 398
 399         if (UNIT_VTABLE(u)->init)
 400                 if ((r = UNIT_VTABLE(u)->init(u)) < 0)
 401                         goto fail;
 402
 403         u->meta.load_state = UNIT_LOADED;
 404         return 0;
 405
 406 fail:
 407         u->meta.load_state = UNIT_FAILED;
 408         return r;
 409 }
 410
 411 /* Errors:
 412  *         -EBADR:    This unit type does not support starting.
 413  *         -EALREADY: Unit is already started.
 414  *         -EAGAIN:   An operation is already in progress. Retry later.
 415  */
 416 int unit_start(Unit *u) {
 417         UnitActiveState state;
 418
 419         assert(u);
 420
 421         if (!UNIT_VTABLE(u)->start)
 422                 return -EBADR;
 423
 424         state = unit_active_state(u);
 425         if (UNIT_IS_ACTIVE_OR_RELOADING(state))
 426                 return -EALREADY;
 427
 428         /* We don't suppress calls to ->start() here when we are
 429          * already starting, to allow this request to be used as a
 430          * "hurry up" call, for example when the unit is in some "auto
 431          * restart" state where it waits for a holdoff timer to elapse
 432          * before it will start again. */
 433
 434         return UNIT_VTABLE(u)->start(u);
 435 }
 436
 437 bool unit_can_start(Unit *u) {
 438         assert(u);
 439
 440         return !!UNIT_VTABLE(u)->start;
 441 }
 442
 443 /* Errors:
 444  *         -EBADR:    This unit type does not support stopping.
 445  *         -EALREADY: Unit is already stopped.
 446  *         -EAGAIN:   An operation is already in progress. Retry later.
 447  */
 448 int unit_stop(Unit *u) {
 449         UnitActiveState state;
 450
 451         assert(u);
 452
 453         if (!UNIT_VTABLE(u)->stop)
 454                 return -EBADR;
 455
 456         state = unit_active_state(u);
 457         if (state == UNIT_INACTIVE)
 458                 return -EALREADY;
 459
 460         if (state == UNIT_DEACTIVATING)
 461                 return 0;
 462
 463         return UNIT_VTABLE(u)->stop(u);
 464 }
 465
 466 /* Errors:
 467  *         -EBADR:    This unit type does not support reloading.
 468  *         -ENOEXEC:  Unit is not started.
 469  *         -EAGAIN:   An operation is already in progress. Retry later.
 470  */
 471 int unit_reload(Unit *u) {
 472         UnitActiveState state;
 473
 474         assert(u);
 475
 476         if (!unit_can_reload(u))
 477                 return -EBADR;
 478
 479         state = unit_active_state(u);
 480         if (unit_active_state(u) == UNIT_ACTIVE_RELOADING)
 481                 return -EALREADY;
 482
 483         if (unit_active_state(u) != UNIT_ACTIVE)
 484                 return -ENOEXEC;
 485
 486         return UNIT_VTABLE(u)->reload(u);
 487 }
 488
 489 bool unit_can_reload(Unit *u) {
 490         assert(u);
 491
 492         if (!UNIT_VTABLE(u)->reload)
 493                 return false;
 494
 495         if (!UNIT_VTABLE(u)->can_reload)
 496                 return true;
 497
 498         return UNIT_VTABLE(u)->can_reload(u);
 499 }
 500
 501 static void retroactively_start_dependencies(Unit *u) {
 502         Iterator i;
 503         Unit *other;
 504
 505         assert(u);
 506         assert(UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u)));
 507
 508         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRES], i)
 509                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 510                         manager_add_job(u->meta.manager, JOB_START, other, JOB_REPLACE, true, NULL);
 511
 512         SET_FOREACH(other, u->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 513                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 514                         manager_add_job(u->meta.manager, JOB_START, other, JOB_FAIL, false, NULL);
 515
 516         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUISITE], i)
 517                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 518                         manager_add_job(u->meta.manager, JOB_START, other, JOB_REPLACE, true, NULL);
 519
 520         SET_FOREACH(other, u->meta.dependencies[UNIT_WANTS], i)
 521                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 522                         manager_add_job(u->meta.manager, JOB_START, other, JOB_FAIL, false, NULL);
 523
 524         SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTS], i)
 525                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 526                         manager_add_job(u->meta.manager, JOB_STOP, other, JOB_REPLACE, true, NULL);
 527 }
 528
 529 static void retroactively_stop_dependencies(Unit *u) {
 530         Iterator i;
 531         Unit *other;
 532
 533         assert(u);
 534         assert(UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(u)));
 535
 536         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
 537                 if (!UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(other)))
 538                         manager_add_job(u->meta.manager, JOB_STOP, other, JOB_REPLACE, true, NULL);
 539 }
 540
 541 void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns) {
 542         assert(u);
 543         assert(os < _UNIT_ACTIVE_STATE_MAX);
 544         assert(ns < _UNIT_ACTIVE_STATE_MAX);
 545         assert(!(os == UNIT_ACTIVE && ns == UNIT_ACTIVATING));
 546         assert(!(os == UNIT_INACTIVE && ns == UNIT_DEACTIVATING));
 547
 548         if (os == ns)
 549                 return;
 550
 551         if (!UNIT_IS_ACTIVE_OR_RELOADING(os) && UNIT_IS_ACTIVE_OR_RELOADING(ns))
 552                 u->meta.active_enter_timestamp = now(CLOCK_REALTIME);
 553         else if (UNIT_IS_ACTIVE_OR_RELOADING(os) && !UNIT_IS_ACTIVE_OR_RELOADING(ns))
 554                 u->meta.active_exit_timestamp = now(CLOCK_REALTIME);
 555
 556         if (u->meta.job) {
 557
 558                 if (u->meta.job->state == JOB_WAITING)
 559
 560                         /* So we reached a different state for this
 561                          * job. Let's see if we can run it now if it
 562                          * failed previously due to EAGAIN. */
 563                         job_schedule_run(u->meta.job);
 564
 565                 else {
 566                         assert(u->meta.job->state == JOB_RUNNING);
 567
 568                         /* Let's check of this state change
 569                          * constitutes a finished job, or maybe
 570                          * cotradicts a running job and hence needs to
 571                          * invalidate jobs. */
 572
 573                         switch (u->meta.job->type) {
 574
 575                         case JOB_START:
 576                         case JOB_VERIFY_ACTIVE:
 577
 578                                 if (UNIT_IS_ACTIVE_OR_RELOADING(ns)) {
 579                                         job_finish_and_invalidate(u->meta.job, true);
 580                                         return;
 581                                 } else if (ns == UNIT_ACTIVATING)
 582                                         return;
 583                                 else
 584                                         job_finish_and_invalidate(u->meta.job, false);
 585
 586                                 break;
 587
 588                         case JOB_RELOAD:
 589                         case JOB_RELOAD_OR_START:
 590
 591                                 if (ns == UNIT_ACTIVE) {
 592                                         job_finish_and_invalidate(u->meta.job, true);
 593                                         return;
 594                                 } else if (ns == UNIT_ACTIVATING || ns == UNIT_ACTIVE_RELOADING)
 595                                         return;
 596                                 else
 597                                         job_finish_and_invalidate(u->meta.job, false);
 598
 599                                 break;
 600
 601                         case JOB_STOP:
 602                         case JOB_RESTART:
 603                         case JOB_TRY_RESTART:
 604
 605                                 if (ns == UNIT_INACTIVE) {
 606                                         job_finish_and_invalidate(u->meta.job, true);
 607                                         return;
 608                                 } else if (ns == UNIT_DEACTIVATING)
 609                                         return;
 610                                 else
 611                                         job_finish_and_invalidate(u->meta.job, false);
 612
 613                                 break;
 614
 615                         default:
 616                                 assert_not_reached("Job type unknown");
 617                         }
 618                 }
 619         }
 620
 621         /* If this state change happened without being requested by a
 622          * job, then let's retroactively start or stop dependencies */
 623
 624         if (UNIT_IS_INACTIVE_OR_DEACTIVATING(os) && UNIT_IS_ACTIVE_OR_ACTIVATING(ns))
 625                 retroactively_start_dependencies(u);
 626         else if (UNIT_IS_ACTIVE_OR_ACTIVATING(os) && UNIT_IS_INACTIVE_OR_DEACTIVATING(ns))
 627                 retroactively_stop_dependencies(u);
 628 }
 629
 630 int unit_watch_fd(Unit *u, int fd, uint32_t events) {
 631         struct epoll_event ev;
 632
 633         assert(u);
 634         assert(fd >= 0);
 635
 636         zero(ev);
 637         ev.data.fd = fd;
 638         ev.data.ptr = u;
 639         ev.data.u32 = MANAGER_FD;
 640         ev.events = events;
 641
 642         if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) >= 0)
 643                 return 0;
 644
 645         if (errno == EEXIST)
 646                 if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_MOD, fd, &ev) >= 0)
 647                         return 0;
 648
 649         return -errno;
 650 }
 651
 652 void unit_unwatch_fd(Unit *u, int fd) {
 653         assert(u);
 654         assert(fd >= 0);
 655
 656         assert_se(epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_DEL, fd, NULL) >= 0 || errno == ENOENT);
 657 }
 658
 659 int unit_watch_pid(Unit *u, pid_t pid) {
 660         assert(u);
 661         assert(pid >= 1);
 662
 663         return hashmap_put(u->meta.manager->watch_pids, UINT32_TO_PTR(pid), u);
 664 }
 665
 666 void unit_unwatch_pid(Unit *u, pid_t pid) {
 667         assert(u);
 668         assert(pid >= 1);
 669
 670         hashmap_remove(u->meta.manager->watch_pids, UINT32_TO_PTR(pid));
 671 }
 672
 673 int unit_watch_timer(Unit *u, usec_t delay, int *id) {
 674         struct epoll_event ev;
 675         int fd;
 676         struct itimerspec its;
 677         int flags;
 678         bool ours;
 679
 680         assert(u);
 681         assert(id);
 682
 683         /* This will try to reuse the old timer if there is one */
 684
 685         if (*id >= 0) {
 686                 ours = false;
 687                 fd = *id;
 688
 689         } else {
 690                 ours = true;
 691
 692                 if ((fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC)) < 0)
 693                         return -errno;
 694         }
 695
 696         zero(its);
 697
 698         if (delay <= 0) {
 699                 /* Set absolute time in the past, but not 0, since we
 700                  * don't want to disarm the timer */
 701                 its.it_value.tv_sec = 0;
 702                 its.it_value.tv_nsec = 1;
 703
 704                 flags = TFD_TIMER_ABSTIME;
 705         } else {
 706                 timespec_store(&its.it_value, delay);
 707                 flags = 0;
 708         }
 709
 710         /* This will also flush the elapse counter */
 711         if (timerfd_settime(fd, flags, &its, NULL) < 0)
 712                 goto fail;
 713
 714         zero(ev);
 715         ev.data.fd = fd;
 716         ev.data.ptr = u;
 717         ev.data.u32 = MANAGER_TIMER;
 718         ev.events = POLLIN;
 719
 720         if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0)
 721                 goto fail;
 722
 723         *id = fd;
 724         return 0;
 725
 726 fail:
 727         if (ours)
 728                 assert_se(close_nointr(fd) == 0);
 729
 730         return -errno;
 731 }
 732
 733 void unit_unwatch_timer(Unit *u, int *id) {
 734         assert(u);
 735         assert(id);
 736
 737         if (*id < 0)
 738                 return;
 739
 740         assert_se(epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_DEL, *id, NULL) >= 0);
 741         assert_se(close_nointr(*id) == 0);
 742         *id = -1;
 743 }
 744
 745 bool unit_job_is_applicable(Unit *u, JobType j) {
 746         assert(u);
 747         assert(j >= 0 && j < _JOB_TYPE_MAX);
 748
 749         switch (j) {
 750
 751         case JOB_VERIFY_ACTIVE:
 752         case JOB_START:
 753                 return true;
 754
 755         case JOB_STOP:
 756         case JOB_RESTART:
 757         case JOB_TRY_RESTART:
 758                 return unit_can_start(u);
 759
 760         case JOB_RELOAD:
 761                 return unit_can_reload(u);
 762
 763         case JOB_RELOAD_OR_START:
 764                 return unit_can_reload(u) && unit_can_start(u);
 765
 766         default:
 767                 assert_not_reached("Invalid job type");
 768         }
 769 }
 770
 771 int unit_add_dependency(Unit *u, UnitDependency d, Unit *other) {
 772
 773         static const UnitDependency inverse_table[_UNIT_DEPENDENCY_MAX] = {
 774                 [UNIT_REQUIRES] = UNIT_REQUIRED_BY,
 775                 [UNIT_SOFT_REQUIRES] = UNIT_SOFT_REQUIRED_BY,
 776                 [UNIT_WANTS] = UNIT_WANTED_BY,
 777                 [UNIT_REQUISITE] = UNIT_REQUIRED_BY,
 778                 [UNIT_SOFT_REQUISITE] = UNIT_SOFT_REQUIRED_BY,
 779                 [UNIT_REQUIRED_BY] = _UNIT_DEPENDENCY_INVALID,
 780                 [UNIT_SOFT_REQUIRED_BY] = _UNIT_DEPENDENCY_INVALID,
 781                 [UNIT_WANTED_BY] = _UNIT_DEPENDENCY_INVALID,
 782                 [UNIT_CONFLICTS] = UNIT_CONFLICTS,
 783                 [UNIT_BEFORE] = UNIT_AFTER,
 784                 [UNIT_AFTER] = UNIT_BEFORE
 785         };
 786         int r;
 787
 788         assert(u);
 789         assert(d >= 0 && d < _UNIT_DEPENDENCY_MAX);
 790         assert(inverse_table[d] != _UNIT_DEPENDENCY_INVALID);
 791         assert(other);
 792
 793         /* We won't allow dependencies on ourselves. We will not
 794          * consider them an error however. */
 795         if (u == other)
 796                 return 0;
 797
 798         if ((r = set_ensure_allocated(&u->meta.dependencies[d], trivial_hash_func, trivial_compare_func)) < 0)
 799                 return r;
 800
 801         if ((r = set_ensure_allocated(&other->meta.dependencies[inverse_table[d]], trivial_hash_func, trivial_compare_func)) < 0)
 802                 return r;
 803
 804         if ((r = set_put(u->meta.dependencies[d], other)) < 0)
 805                 return r;
 806
 807         if ((r = set_put(other->meta.dependencies[inverse_table[d]], u)) < 0) {
 808                 set_remove(u->meta.dependencies[d], other);
 809                 return r;
 810         }
 811
 812         return 0;
 813 }
 814
 815 const char *unit_path(void) {
 816         char *e;
 817
 818         if ((e = getenv("UNIT_PATH")))
 819                 if (path_is_absolute(e))
 820                     return e;
 821
 822         return UNIT_PATH;
 823 }
 824
 825 int set_unit_path(const char *p) {
 826         char *cwd, *c;
 827         int r;
 828
 829         /* This is mostly for debug purposes */
 830
 831         if (path_is_absolute(p)) {
 832                 if (!(c = strdup(p)))
 833                         return -ENOMEM;
 834         } else {
 835                 if (!(cwd = get_current_dir_name()))
 836                         return -errno;
 837
 838                 r = asprintf(&c, "%s/%s", cwd, p);
 839                 free(cwd);
 840
 841                 if (r < 0)
 842                         return -ENOMEM;
 843         }
 844
 845         if (setenv("UNIT_PATH", c, 0) < 0) {
 846                 r = -errno;
 847                 free(c);
 848                 return r;
 849         }
 850
 851         return 0;
 852 }