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