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         if (e == n)
  66                 return false;
  67
  68         for (i = n; i < e; i++)
  69                 if (!strchr(VALID_CHARS, *i))
  70                         return false;
  71
  72         return true;
  73 }
  74
  75 char *unit_name_change_suffix(const char *n, const char *suffix) {
  76         char *e, *r;
  77         size_t a, b;
  78
  79         assert(n);
  80         assert(unit_name_is_valid(n));
  81         assert(suffix);
  82
  83         assert_se(e = strrchr(n, '.'));
  84         a = e - n;
  85         b = strlen(suffix);
  86
  87         if (!(r = new(char, a + b + 1)))
  88                 return NULL;
  89
  90         memcpy(r, n, a);
  91         memcpy(r+a, suffix, b+1);
  92
  93         return r;
  94 }
  95
  96 Unit *unit_new(Manager *m) {
  97         Unit *u;
  98
  99         assert(m);
 100
 101         if (!(u = new0(Unit, 1)))
 102                 return NULL;
 103
 104         if (!(u->meta.names = set_new(string_hash_func, string_compare_func))) {
 105                 free(u);
 106                 return NULL;
 107         }
 108
 109         u->meta.manager = m;
 110         u->meta.type = _UNIT_TYPE_INVALID;
 111
 112         return u;
 113 }
 114
 115 int unit_add_name(Unit *u, const char *text) {
 116         UnitType t;
 117         char *s;
 118         int r;
 119
 120         assert(u);
 121         assert(text);
 122
 123         if (!unit_name_is_valid(text))
 124                 return -EINVAL;
 125
 126         if ((t = unit_name_to_type(text)) == _UNIT_TYPE_INVALID)
 127                 return -EINVAL;
 128
 129         if (u->meta.type != _UNIT_TYPE_INVALID && t != u->meta.type)
 130                 return -EINVAL;
 131
 132         if (!(s = strdup(text)))
 133                 return -ENOMEM;
 134
 135         if ((r = set_put(u->meta.names, s)) < 0) {
 136                 free(s);
 137
 138                 if (r == -EEXIST)
 139                         return 0;
 140
 141                 return r;
 142         }
 143
 144         if ((r = hashmap_put(u->meta.manager->units, s, u)) < 0) {
 145                 set_remove(u->meta.names, s);
 146                 free(s);
 147                 return r;
 148         }
 149
 150         u->meta.type = t;
 151
 152         if (!u->meta.id)
 153                 u->meta.id = s;
 154
 155         return 0;
 156 }
 157
 158 void unit_add_to_load_queue(Unit *u) {
 159         assert(u);
 160
 161         if (u->meta.load_state != UNIT_STUB || u->meta.in_load_queue)
 162                 return;
 163
 164         LIST_PREPEND(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
 165         u->meta.in_load_queue = true;
 166 }
 167
 168 static void bidi_set_free(Unit *u, Set *s) {
 169         Iterator i;
 170         Unit *other;
 171
 172         assert(u);
 173
 174         /* Frees the set and makes sure we are dropped from the
 175          * inverse pointers */
 176
 177         SET_FOREACH(other, s, i) {
 178                 UnitDependency d;
 179
 180                 for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
 181                         set_remove(other->meta.dependencies[d], u);
 182         }
 183
 184         set_free(s);
 185 }
 186
 187 void unit_free(Unit *u) {
 188         UnitDependency d;
 189         Iterator i;
 190         char *t;
 191
 192         assert(u);
 193
 194         /* Detach from next 'bigger' objects */
 195
 196         SET_FOREACH(t, u->meta.names, i)
 197                 hashmap_remove_value(u->meta.manager->units, t, u);
 198
 199         if (u->meta.in_load_queue)
 200                 LIST_REMOVE(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
 201
 202         if (u->meta.load_state == UNIT_LOADED)
 203                 if (UNIT_VTABLE(u)->done)
 204                         UNIT_VTABLE(u)->done(u);
 205
 206         /* Free data and next 'smaller' objects */
 207         if (u->meta.job)
 208                 job_free(u->meta.job);
 209
 210         for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
 211                 bidi_set_free(u, u->meta.dependencies[d]);
 212
 213         free(u->meta.description);
 214         free(u->meta.load_path);
 215
 216         while ((t = set_steal_first(u->meta.names)))
 217                 free(t);
 218         set_free(u->meta.names);
 219
 220         free(u);
 221 }
 222
 223 UnitActiveState unit_active_state(Unit *u) {
 224         assert(u);
 225
 226         if (u->meta.load_state != UNIT_LOADED)
 227                 return UNIT_INACTIVE;
 228
 229         return UNIT_VTABLE(u)->active_state(u);
 230 }
 231
 232 static int ensure_merge(Set **s, Set *other) {
 233
 234         if (!other)
 235                 return 0;
 236
 237         if (*s)
 238                 return set_merge(*s, other);
 239
 240         if (!(*s = set_copy(other)))
 241                 return -ENOMEM;
 242
 243         return 0;
 244 }
 245
 246 /* FIXME: Does not rollback on failure! Needs to fix special unit
 247  * pointers. Needs to merge names and dependencies properly.*/
 248 int unit_merge(Unit *u, Unit *other) {
 249         int r;
 250         UnitDependency d;
 251
 252         assert(u);
 253         assert(other);
 254         assert(u->meta.manager == other->meta.manager);
 255
 256         /* This merges 'other' into 'unit'. FIXME: This does not
 257          * rollback on failure. */
 258
 259         if (u->meta.type != u->meta.type)
 260                 return -EINVAL;
 261
 262         if (u->meta.load_state != UNIT_STUB)
 263                 return -EINVAL;
 264
 265         /* Merge names */
 266         if ((r = ensure_merge(&u->meta.names, other->meta.names)) < 0)
 267                 return r;
 268
 269         /* Merge dependencies */
 270         for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++)
 271                 /* fixme, the inverse mapping is missing */
 272                 if ((r = ensure_merge(&u->meta.dependencies[d], other->meta.dependencies[d])) < 0)
 273                         return r;
 274
 275         return 0;
 276 }
 277
 278 const char* unit_id(Unit *u) {
 279         assert(u);
 280
 281         if (u->meta.id)
 282                 return u->meta.id;
 283
 284         return set_first(u->meta.names);
 285 }
 286
 287 const char *unit_description(Unit *u) {
 288         assert(u);
 289
 290         if (u->meta.description)
 291                 return u->meta.description;
 292
 293         return unit_id(u);
 294 }
 295
 296 void unit_dump(Unit *u, FILE *f, const char *prefix) {
 297
 298         static const char* const load_state_table[_UNIT_LOAD_STATE_MAX] = {
 299                 [UNIT_STUB] = "stub",
 300                 [UNIT_LOADED] = "loaded",
 301                 [UNIT_FAILED] = "failed"
 302         };
 303
 304         static const char* const active_state_table[_UNIT_ACTIVE_STATE_MAX] = {
 305                 [UNIT_ACTIVE] = "active",
 306                 [UNIT_INACTIVE] = "inactive",
 307                 [UNIT_ACTIVATING] = "activating",
 308                 [UNIT_DEACTIVATING] = "deactivating"
 309         };
 310
 311         static const char* const dependency_table[_UNIT_DEPENDENCY_MAX] = {
 312                 [UNIT_REQUIRES] = "Requires",
 313                 [UNIT_SOFT_REQUIRES] = "SoftRequires",
 314                 [UNIT_WANTS] = "Wants",
 315                 [UNIT_REQUISITE] = "Requisite",
 316                 [UNIT_SOFT_REQUISITE] = "SoftRequisite",
 317                 [UNIT_REQUIRED_BY] = "RequiredBy",
 318                 [UNIT_SOFT_REQUIRED_BY] = "SoftRequiredBy",
 319                 [UNIT_WANTED_BY] = "WantedBy",
 320                 [UNIT_CONFLICTS] = "Conflicts",
 321                 [UNIT_BEFORE] = "Before",
 322                 [UNIT_AFTER] = "After",
 323         };
 324
 325         char *t;
 326         UnitDependency d;
 327         Iterator i;
 328         char *prefix2;
 329
 330         assert(u);
 331
 332         if (!prefix)
 333                 prefix = "";
 334         prefix2 = strappend(prefix, "\t");
 335         if (!prefix2)
 336                 prefix2 = "";
 337
 338         fprintf(f,
 339                 "%s→ Unit %s:\n"
 340                 "%s\tDescription: %s\n"
 341                 "%s\tUnit Load State: %s\n"
 342                 "%s\tUnit Active State: %s\n",
 343                 prefix, unit_id(u),
 344                 prefix, unit_description(u),
 345                 prefix, load_state_table[u->meta.load_state],
 346                 prefix, active_state_table[unit_active_state(u)]);
 347
 348         if (u->meta.load_path)
 349                 fprintf(f, "%s\tLoad Path: %s\n", prefix, u->meta.load_path);
 350
 351         SET_FOREACH(t, u->meta.names, i)
 352                 fprintf(f, "%s\tName: %s\n", prefix, t);
 353
 354         for (d = 0; d < _UNIT_DEPENDENCY_MAX; d++) {
 355                 Unit *other;
 356
 357                 if (set_isempty(u->meta.dependencies[d]))
 358                         continue;
 359
 360                 SET_FOREACH(other, u->meta.dependencies[d], i)
 361                         fprintf(f, "%s\t%s: %s\n", prefix, dependency_table[d], unit_id(other));
 362         }
 363
 364         if (UNIT_VTABLE(u)->dump)
 365                 UNIT_VTABLE(u)->dump(u, f, prefix2);
 366
 367         if (u->meta.job)
 368                 job_dump(u->meta.job, f, prefix2);
 369
 370         free(prefix2);
 371 }
 372
 373 /* Common implementation for multiple backends */
 374 int unit_load_fragment_and_dropin(Unit *u) {
 375         int r;
 376
 377         assert(u);
 378
 379         /* Load a .socket file */
 380         if ((r = unit_load_fragment(u)) < 0)
 381                 return r;
 382
 383         /* Load drop-in directory data */
 384         if ((r = unit_load_dropin(u)) < 0)
 385                 return r;
 386
 387         return 0;
 388 }
 389
 390 int unit_load(Unit *u) {
 391         int r;
 392
 393         assert(u);
 394
 395         if (u->meta.in_load_queue) {
 396                 LIST_REMOVE(Meta, load_queue, u->meta.manager->load_queue, &u->meta);
 397                 u->meta.in_load_queue = false;
 398         }
 399
 400         if (u->meta.load_state != UNIT_STUB)
 401                 return 0;
 402
 403         if (UNIT_VTABLE(u)->init)
 404                 if ((r = UNIT_VTABLE(u)->init(u)) < 0)
 405                         goto fail;
 406
 407         u->meta.load_state = UNIT_LOADED;
 408         return 0;
 409
 410 fail:
 411         u->meta.load_state = UNIT_FAILED;
 412         return r;
 413 }
 414
 415 /* Errors:
 416  *         -EBADR:    This unit type does not support starting.
 417  *         -EALREADY: Unit is already started.
 418  *         -EAGAIN:   An operation is already in progress. Retry later.
 419  */
 420 int unit_start(Unit *u) {
 421         UnitActiveState state;
 422
 423         assert(u);
 424
 425         if (!UNIT_VTABLE(u)->start)
 426                 return -EBADR;
 427
 428         state = unit_active_state(u);
 429         if (UNIT_IS_ACTIVE_OR_RELOADING(state))
 430                 return -EALREADY;
 431
 432         /* We don't suppress calls to ->start() here when we are
 433          * already starting, to allow this request to be used as a
 434          * "hurry up" call, for example when the unit is in some "auto
 435          * restart" state where it waits for a holdoff timer to elapse
 436          * before it will start again. */
 437
 438         return UNIT_VTABLE(u)->start(u);
 439 }
 440
 441 bool unit_can_start(Unit *u) {
 442         assert(u);
 443
 444         return !!UNIT_VTABLE(u)->start;
 445 }
 446
 447 /* Errors:
 448  *         -EBADR:    This unit type does not support stopping.
 449  *         -EALREADY: Unit is already stopped.
 450  *         -EAGAIN:   An operation is already in progress. Retry later.
 451  */
 452 int unit_stop(Unit *u) {
 453         UnitActiveState state;
 454
 455         assert(u);
 456
 457         if (!UNIT_VTABLE(u)->stop)
 458                 return -EBADR;
 459
 460         state = unit_active_state(u);
 461         if (state == UNIT_INACTIVE)
 462                 return -EALREADY;
 463
 464         if (state == UNIT_DEACTIVATING)
 465                 return 0;
 466
 467         return UNIT_VTABLE(u)->stop(u);
 468 }
 469
 470 /* Errors:
 471  *         -EBADR:    This unit type does not support reloading.
 472  *         -ENOEXEC:  Unit is not started.
 473  *         -EAGAIN:   An operation is already in progress. Retry later.
 474  */
 475 int unit_reload(Unit *u) {
 476         UnitActiveState state;
 477
 478         assert(u);
 479
 480         if (!unit_can_reload(u))
 481                 return -EBADR;
 482
 483         state = unit_active_state(u);
 484         if (unit_active_state(u) == UNIT_ACTIVE_RELOADING)
 485                 return -EALREADY;
 486
 487         if (unit_active_state(u) != UNIT_ACTIVE)
 488                 return -ENOEXEC;
 489
 490         return UNIT_VTABLE(u)->reload(u);
 491 }
 492
 493 bool unit_can_reload(Unit *u) {
 494         assert(u);
 495
 496         if (!UNIT_VTABLE(u)->reload)
 497                 return false;
 498
 499         if (!UNIT_VTABLE(u)->can_reload)
 500                 return true;
 501
 502         return UNIT_VTABLE(u)->can_reload(u);
 503 }
 504
 505 static void retroactively_start_dependencies(Unit *u) {
 506         Iterator i;
 507         Unit *other;
 508
 509         assert(u);
 510         assert(UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u)));
 511
 512         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRES], i)
 513                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 514                         manager_add_job(u->meta.manager, JOB_START, other, JOB_REPLACE, true, NULL);
 515
 516         SET_FOREACH(other, u->meta.dependencies[UNIT_SOFT_REQUIRES], i)
 517                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 518                         manager_add_job(u->meta.manager, JOB_START, other, JOB_FAIL, false, NULL);
 519
 520         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUISITE], i)
 521                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 522                         manager_add_job(u->meta.manager, JOB_START, other, JOB_REPLACE, true, NULL);
 523
 524         SET_FOREACH(other, u->meta.dependencies[UNIT_WANTS], i)
 525                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 526                         manager_add_job(u->meta.manager, JOB_START, other, JOB_FAIL, false, NULL);
 527
 528         SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTS], i)
 529                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 530                         manager_add_job(u->meta.manager, JOB_STOP, other, JOB_REPLACE, true, NULL);
 531 }
 532
 533 static void retroactively_stop_dependencies(Unit *u) {
 534         Iterator i;
 535         Unit *other;
 536
 537         assert(u);
 538         assert(UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(u)));
 539
 540         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
 541                 if (!UNIT_IS_INACTIVE_OR_DEACTIVATING(unit_active_state(other)))
 542                         manager_add_job(u->meta.manager, JOB_STOP, other, JOB_REPLACE, true, NULL);
 543 }
 544
 545 void unit_notify(Unit *u, UnitActiveState os, UnitActiveState ns) {
 546         assert(u);
 547         assert(os < _UNIT_ACTIVE_STATE_MAX);
 548         assert(ns < _UNIT_ACTIVE_STATE_MAX);
 549         assert(!(os == UNIT_ACTIVE && ns == UNIT_ACTIVATING));
 550         assert(!(os == UNIT_INACTIVE && ns == UNIT_DEACTIVATING));
 551
 552         if (os == ns)
 553                 return;
 554
 555         if (!UNIT_IS_ACTIVE_OR_RELOADING(os) && UNIT_IS_ACTIVE_OR_RELOADING(ns))
 556                 u->meta.active_enter_timestamp = now(CLOCK_REALTIME);
 557         else if (UNIT_IS_ACTIVE_OR_RELOADING(os) && !UNIT_IS_ACTIVE_OR_RELOADING(ns))
 558                 u->meta.active_exit_timestamp = now(CLOCK_REALTIME);
 559
 560         if (u->meta.job) {
 561
 562                 if (u->meta.job->state == JOB_WAITING)
 563
 564                         /* So we reached a different state for this
 565                          * job. Let's see if we can run it now if it
 566                          * failed previously due to EAGAIN. */
 567                         job_schedule_run(u->meta.job);
 568
 569                 else {
 570                         assert(u->meta.job->state == JOB_RUNNING);
 571
 572                         /* Let's check of this state change
 573                          * constitutes a finished job, or maybe
 574                          * cotradicts a running job and hence needs to
 575                          * invalidate jobs. */
 576
 577                         switch (u->meta.job->type) {
 578
 579                         case JOB_START:
 580                         case JOB_VERIFY_ACTIVE:
 581
 582                                 if (UNIT_IS_ACTIVE_OR_RELOADING(ns)) {
 583                                         job_finish_and_invalidate(u->meta.job, true);
 584                                         return;
 585                                 } else if (ns == UNIT_ACTIVATING)
 586                                         return;
 587                                 else
 588                                         job_finish_and_invalidate(u->meta.job, false);
 589
 590                                 break;
 591
 592                         case JOB_RELOAD:
 593                         case JOB_RELOAD_OR_START:
 594
 595                                 if (ns == UNIT_ACTIVE) {
 596                                         job_finish_and_invalidate(u->meta.job, true);
 597                                         return;
 598                                 } else if (ns == UNIT_ACTIVATING || ns == UNIT_ACTIVE_RELOADING)
 599                                         return;
 600                                 else
 601                                         job_finish_and_invalidate(u->meta.job, false);
 602
 603                                 break;
 604
 605                         case JOB_STOP:
 606                         case JOB_RESTART:
 607                         case JOB_TRY_RESTART:
 608
 609                                 if (ns == UNIT_INACTIVE) {
 610                                         job_finish_and_invalidate(u->meta.job, true);
 611                                         return;
 612                                 } else if (ns == UNIT_DEACTIVATING)
 613                                         return;
 614                                 else
 615                                         job_finish_and_invalidate(u->meta.job, false);
 616
 617                                 break;
 618
 619                         default:
 620                                 assert_not_reached("Job type unknown");
 621                         }
 622                 }
 623         }
 624
 625         /* If this state change happened without being requested by a
 626          * job, then let's retroactively start or stop dependencies */
 627
 628         if (UNIT_IS_INACTIVE_OR_DEACTIVATING(os) && UNIT_IS_ACTIVE_OR_ACTIVATING(ns))
 629                 retroactively_start_dependencies(u);
 630         else if (UNIT_IS_ACTIVE_OR_ACTIVATING(os) && UNIT_IS_INACTIVE_OR_DEACTIVATING(ns))
 631                 retroactively_stop_dependencies(u);
 632 }
 633
 634 int unit_watch_fd(Unit *u, int fd, uint32_t events, Watch *w) {
 635         struct epoll_event ev;
 636
 637         assert(u);
 638         assert(fd >= 0);
 639         assert(w);
 640         assert(w->type == WATCH_INVALID || (w->type == WATCH_FD && w->fd == fd && w->unit == u));
 641
 642         zero(ev);
 643         ev.data.ptr = w;
 644         ev.events = events;
 645
 646         if (epoll_ctl(u->meta.manager->epoll_fd,
 647                       w->type == WATCH_INVALID ? EPOLL_CTL_ADD : EPOLL_CTL_MOD,
 648                       fd,
 649                       &ev) < 0)
 650                 return -errno;
 651
 652         w->fd = fd;
 653         w->type = WATCH_FD;
 654         w->unit = u;
 655
 656         return 0;
 657 }
 658
 659 void unit_unwatch_fd(Unit *u, Watch *w) {
 660         assert(u);
 661         assert(w);
 662
 663         if (w->type == WATCH_INVALID)
 664                 return;
 665
 666         assert(w->type == WATCH_FD && w->unit == u);
 667         assert_se(epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_DEL, w->fd, NULL) >= 0);
 668
 669         w->fd = -1;
 670         w->type = WATCH_INVALID;
 671         w->unit = NULL;
 672 }
 673
 674 int unit_watch_pid(Unit *u, pid_t pid) {
 675         assert(u);
 676         assert(pid >= 1);
 677
 678         return hashmap_put(u->meta.manager->watch_pids, UINT32_TO_PTR(pid), u);
 679 }
 680
 681 void unit_unwatch_pid(Unit *u, pid_t pid) {
 682         assert(u);
 683         assert(pid >= 1);
 684
 685         hashmap_remove(u->meta.manager->watch_pids, UINT32_TO_PTR(pid));
 686 }
 687
 688 int unit_watch_timer(Unit *u, usec_t delay, Watch *w) {
 689         struct itimerspec its;
 690         int flags, fd;
 691         bool ours;
 692
 693         assert(u);
 694         assert(w);
 695         assert(w->type == WATCH_INVALID || (w->type == WATCH_TIMER && w->unit == u));
 696
 697         /* This will try to reuse the old timer if there is one */
 698
 699         if (w->type == WATCH_TIMER) {
 700                 ours = false;
 701                 fd = w->fd;
 702         } else {
 703                 ours = true;
 704                 if ((fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK|TFD_CLOEXEC)) < 0)
 705                         return -errno;
 706         }
 707
 708         zero(its);
 709
 710         if (delay <= 0) {
 711                 /* Set absolute time in the past, but not 0, since we
 712                  * don't want to disarm the timer */
 713                 its.it_value.tv_sec = 0;
 714                 its.it_value.tv_nsec = 1;
 715
 716                 flags = TFD_TIMER_ABSTIME;
 717         } else {
 718                 timespec_store(&its.it_value, delay);
 719                 flags = 0;
 720         }
 721
 722         /* This will also flush the elapse counter */
 723         if (timerfd_settime(fd, flags, &its, NULL) < 0)
 724                 goto fail;
 725
 726         if (w->type == WATCH_INVALID) {
 727                 struct epoll_event ev;
 728
 729                 zero(ev);
 730                 ev.data.ptr = w;
 731                 ev.events = POLLIN;
 732
 733                 if (epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0)
 734                         goto fail;
 735         }
 736
 737         w->fd = fd;
 738         w->type = WATCH_TIMER;
 739         w->unit = u;
 740
 741         return 0;
 742
 743 fail:
 744         if (ours)
 745                 assert_se(close_nointr(fd) == 0);
 746
 747         return -errno;
 748 }
 749
 750 void unit_unwatch_timer(Unit *u, Watch *w) {
 751         assert(u);
 752         assert(w);
 753
 754         if (w->type == WATCH_INVALID)
 755                 return;
 756
 757         assert(w->type == WATCH_TIMER && w->unit == u);
 758
 759         assert_se(epoll_ctl(u->meta.manager->epoll_fd, EPOLL_CTL_DEL, w->fd, NULL) >= 0);
 760         assert_se(close_nointr(w->fd) == 0);
 761
 762         w->fd = -1;
 763         w->type = WATCH_INVALID;
 764         w->unit = NULL;
 765 }
 766
 767 bool unit_job_is_applicable(Unit *u, JobType j) {
 768         assert(u);
 769         assert(j >= 0 && j < _JOB_TYPE_MAX);
 770
 771         switch (j) {
 772
 773         case JOB_VERIFY_ACTIVE:
 774         case JOB_START:
 775                 return true;
 776
 777         case JOB_STOP:
 778         case JOB_RESTART:
 779         case JOB_TRY_RESTART:
 780                 return unit_can_start(u);
 781
 782         case JOB_RELOAD:
 783                 return unit_can_reload(u);
 784
 785         case JOB_RELOAD_OR_START:
 786                 return unit_can_reload(u) && unit_can_start(u);
 787
 788         default:
 789                 assert_not_reached("Invalid job type");
 790         }
 791 }
 792
 793 int unit_add_dependency(Unit *u, UnitDependency d, Unit *other) {
 794
 795         static const UnitDependency inverse_table[_UNIT_DEPENDENCY_MAX] = {
 796                 [UNIT_REQUIRES] = UNIT_REQUIRED_BY,
 797                 [UNIT_SOFT_REQUIRES] = UNIT_SOFT_REQUIRED_BY,
 798                 [UNIT_WANTS] = UNIT_WANTED_BY,
 799                 [UNIT_REQUISITE] = UNIT_REQUIRED_BY,
 800                 [UNIT_SOFT_REQUISITE] = UNIT_SOFT_REQUIRED_BY,
 801                 [UNIT_REQUIRED_BY] = _UNIT_DEPENDENCY_INVALID,
 802                 [UNIT_SOFT_REQUIRED_BY] = _UNIT_DEPENDENCY_INVALID,
 803                 [UNIT_WANTED_BY] = _UNIT_DEPENDENCY_INVALID,
 804                 [UNIT_CONFLICTS] = UNIT_CONFLICTS,
 805                 [UNIT_BEFORE] = UNIT_AFTER,
 806                 [UNIT_AFTER] = UNIT_BEFORE
 807         };
 808         int r;
 809
 810         assert(u);
 811         assert(d >= 0 && d < _UNIT_DEPENDENCY_MAX);
 812         assert(inverse_table[d] != _UNIT_DEPENDENCY_INVALID);
 813         assert(other);
 814
 815         /* We won't allow dependencies on ourselves. We will not
 816          * consider them an error however. */
 817         if (u == other)
 818                 return 0;
 819
 820         if ((r = set_ensure_allocated(&u->meta.dependencies[d], trivial_hash_func, trivial_compare_func)) < 0)
 821                 return r;
 822
 823         if ((r = set_ensure_allocated(&other->meta.dependencies[inverse_table[d]], trivial_hash_func, trivial_compare_func)) < 0)
 824                 return r;
 825
 826         if ((r = set_put(u->meta.dependencies[d], other)) < 0)
 827                 return r;
 828
 829         if ((r = set_put(other->meta.dependencies[inverse_table[d]], u)) < 0) {
 830                 set_remove(u->meta.dependencies[d], other);
 831                 return r;
 832         }
 833
 834         return 0;
 835 }
 836
 837 const char *unit_path(void) {
 838         char *e;
 839
 840         if ((e = getenv("UNIT_PATH")))
 841                 if (path_is_absolute(e))
 842                     return e;
 843
 844         return UNIT_PATH;
 845 }
 846
 847 int set_unit_path(const char *p) {
 848         char *cwd, *c;
 849         int r;
 850
 851         /* This is mostly for debug purposes */
 852
 853         if (path_is_absolute(p)) {
 854                 if (!(c = strdup(p)))
 855                         return -ENOMEM;
 856         } else {
 857                 if (!(cwd = get_current_dir_name()))
 858                         return -errno;
 859
 860                 r = asprintf(&c, "%s/%s", cwd, p);
 861                 free(cwd);
 862
 863                 if (r < 0)
 864                         return -ENOMEM;
 865         }
 866
 867         if (setenv("UNIT_PATH", c, 0) < 0) {
 868                 r = -errno;
 869                 free(c);
 870                 return r;
 871         }
 872
 873         return 0;
 874 }