src/core/timer.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <errno.h>
   4
   5 #include "alloc-util.h"
   6 #include "bus-error.h"
   7 #include "bus-util.h"
   8 #include "dbus-timer.h"
   9 #include "dbus-unit.h"
  10 #include "fs-util.h"
  11 #include "parse-util.h"
  12 #include "random-util.h"
  13 #include "serialize.h"
  14 #include "special.h"
  15 #include "string-table.h"
  16 #include "string-util.h"
  17 #include "timer.h"
  18 #include "unit-name.h"
  19 #include "unit.h"
  20 #include "user-util.h"
  21 #include "virt.h"
  22
  23 static const UnitActiveState state_translation_table[_TIMER_STATE_MAX] = {
  24         [TIMER_DEAD] = UNIT_INACTIVE,
  25         [TIMER_WAITING] = UNIT_ACTIVE,
  26         [TIMER_RUNNING] = UNIT_ACTIVE,
  27         [TIMER_ELAPSED] = UNIT_ACTIVE,
  28         [TIMER_FAILED] = UNIT_FAILED
  29 };
  30
  31 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata);
  32
  33 static void timer_init(Unit *u) {
  34         Timer *t = TIMER(u);
  35
  36         assert(u);
  37         assert(u->load_state == UNIT_STUB);
  38
  39         t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
  40         t->next_elapse_realtime = USEC_INFINITY;
  41         t->accuracy_usec = u->manager->default_timer_accuracy_usec;
  42         t->remain_after_elapse = true;
  43 }
  44
  45 void timer_free_values(Timer *t) {
  46         TimerValue *v;
  47
  48         assert(t);
  49
  50         while ((v = t->values)) {
  51                 LIST_REMOVE(value, t->values, v);
  52                 calendar_spec_free(v->calendar_spec);
  53                 free(v);
  54         }
  55 }
  56
  57 static void timer_done(Unit *u) {
  58         Timer *t = TIMER(u);
  59
  60         assert(t);
  61
  62         timer_free_values(t);
  63
  64         t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
  65         t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
  66
  67         free(t->stamp_path);
  68 }
  69
  70 static int timer_verify(Timer *t) {
  71         assert(t);
  72
  73         if (UNIT(t)->load_state != UNIT_LOADED)
  74                 return 0;
  75
  76         if (!t->values) {
  77                 log_unit_error(UNIT(t), "Timer unit lacks value setting. Refusing.");
  78                 return -ENOEXEC;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int timer_add_default_dependencies(Timer *t) {
  85         int r;
  86         TimerValue *v;
  87
  88         assert(t);
  89
  90         if (!UNIT(t)->default_dependencies)
  91                 return 0;
  92
  93         r = unit_add_dependency_by_name(UNIT(t), UNIT_BEFORE, SPECIAL_TIMERS_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  94         if (r < 0)
  95                 return r;
  96
  97         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
  98                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  99                 if (r < 0)
 100                         return r;
 101
 102                 LIST_FOREACH(value, v, t->values) {
 103                         if (v->base == TIMER_CALENDAR) {
 104                                 r = unit_add_dependency_by_name(UNIT(t), UNIT_AFTER, SPECIAL_TIME_SYNC_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
 105                                 if (r < 0)
 106                                         return r;
 107                                 break;
 108                         }
 109                 }
 110         }
 111
 112         return unit_add_two_dependencies_by_name(UNIT(t), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
 113 }
 114
 115 static int timer_add_trigger_dependencies(Timer *t) {
 116         Unit *x;
 117         int r;
 118
 119         assert(t);
 120
 121         if (!hashmap_isempty(UNIT(t)->dependencies[UNIT_TRIGGERS]))
 122                 return 0;
 123
 124         r = unit_load_related_unit(UNIT(t), ".service", &x);
 125         if (r < 0)
 126                 return r;
 127
 128         return unit_add_two_dependencies(UNIT(t), UNIT_BEFORE, UNIT_TRIGGERS, x, true, UNIT_DEPENDENCY_IMPLICIT);
 129 }
 130
 131 static int timer_setup_persistent(Timer *t) {
 132         int r;
 133
 134         assert(t);
 135
 136         if (!t->persistent)
 137                 return 0;
 138
 139         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
 140
 141                 r = unit_require_mounts_for(UNIT(t), "/var/lib/systemd/timers", UNIT_DEPENDENCY_FILE);
 142                 if (r < 0)
 143                         return r;
 144
 145                 t->stamp_path = strappend("/var/lib/systemd/timers/stamp-", UNIT(t)->id);
 146         } else {
 147                 const char *e;
 148
 149                 e = getenv("XDG_DATA_HOME");
 150                 if (e)
 151                         t->stamp_path = strjoin(e, "/systemd/timers/stamp-", UNIT(t)->id);
 152                 else {
 153
 154                         _cleanup_free_ char *h = NULL;
 155
 156                         r = get_home_dir(&h);
 157                         if (r < 0)
 158                                 return log_unit_error_errno(UNIT(t), r, "Failed to determine home directory: %m");
 159
 160                         t->stamp_path = strjoin(h, "/.local/share/systemd/timers/stamp-", UNIT(t)->id);
 161                 }
 162         }
 163
 164         if (!t->stamp_path)
 165                 return log_oom();
 166
 167         return 0;
 168 }
 169
 170 static int timer_load(Unit *u) {
 171         Timer *t = TIMER(u);
 172         int r;
 173
 174         assert(u);
 175         assert(u->load_state == UNIT_STUB);
 176
 177         r = unit_load_fragment_and_dropin(u);
 178         if (r < 0)
 179                 return r;
 180
 181         if (u->load_state == UNIT_LOADED) {
 182
 183                 r = timer_add_trigger_dependencies(t);
 184                 if (r < 0)
 185                         return r;
 186
 187                 r = timer_setup_persistent(t);
 188                 if (r < 0)
 189                         return r;
 190
 191                 r = timer_add_default_dependencies(t);
 192                 if (r < 0)
 193                         return r;
 194         }
 195
 196         return timer_verify(t);
 197 }
 198
 199 static void timer_dump(Unit *u, FILE *f, const char *prefix) {
 200         char buf[FORMAT_TIMESPAN_MAX];
 201         Timer *t = TIMER(u);
 202         Unit *trigger;
 203         TimerValue *v;
 204
 205         trigger = UNIT_TRIGGER(u);
 206
 207         fprintf(f,
 208                 "%sTimer State: %s\n"
 209                 "%sResult: %s\n"
 210                 "%sUnit: %s\n"
 211                 "%sPersistent: %s\n"
 212                 "%sWakeSystem: %s\n"
 213                 "%sAccuracy: %s\n"
 214                 "%sRemainAfterElapse: %s\n",
 215                 prefix, timer_state_to_string(t->state),
 216                 prefix, timer_result_to_string(t->result),
 217                 prefix, trigger ? trigger->id : "n/a",
 218                 prefix, yes_no(t->persistent),
 219                 prefix, yes_no(t->wake_system),
 220                 prefix, format_timespan(buf, sizeof(buf), t->accuracy_usec, 1),
 221                 prefix, yes_no(t->remain_after_elapse));
 222
 223         LIST_FOREACH(value, v, t->values) {
 224
 225                 if (v->base == TIMER_CALENDAR) {
 226                         _cleanup_free_ char *p = NULL;
 227
 228                         (void) calendar_spec_to_string(v->calendar_spec, &p);
 229
 230                         fprintf(f,
 231                                 "%s%s: %s\n",
 232                                 prefix,
 233                                 timer_base_to_string(v->base),
 234                                 strna(p));
 235                 } else  {
 236                         char timespan1[FORMAT_TIMESPAN_MAX];
 237
 238                         fprintf(f,
 239                                 "%s%s: %s\n",
 240                                 prefix,
 241                                 timer_base_to_string(v->base),
 242                                 format_timespan(timespan1, sizeof(timespan1), v->value, 0));
 243                 }
 244         }
 245 }
 246
 247 static void timer_set_state(Timer *t, TimerState state) {
 248         TimerState old_state;
 249         assert(t);
 250
 251         if (t->state != state)
 252                 bus_unit_send_pending_change_signal(UNIT(t), false);
 253
 254         old_state = t->state;
 255         t->state = state;
 256
 257         if (state != TIMER_WAITING) {
 258                 t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
 259                 t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
 260                 t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
 261                 t->next_elapse_realtime = USEC_INFINITY;
 262         }
 263
 264         if (state != old_state)
 265                 log_unit_debug(UNIT(t), "Changed %s -> %s", timer_state_to_string(old_state), timer_state_to_string(state));
 266
 267         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], 0);
 268 }
 269
 270 static void timer_enter_waiting(Timer *t, bool time_change);
 271
 272 static int timer_coldplug(Unit *u) {
 273         Timer *t = TIMER(u);
 274
 275         assert(t);
 276         assert(t->state == TIMER_DEAD);
 277
 278         if (t->deserialized_state == t->state)
 279                 return 0;
 280
 281         if (t->deserialized_state == TIMER_WAITING)
 282                 timer_enter_waiting(t, false);
 283         else
 284                 timer_set_state(t, t->deserialized_state);
 285
 286         return 0;
 287 }
 288
 289 static void timer_enter_dead(Timer *t, TimerResult f) {
 290         assert(t);
 291
 292         if (t->result == TIMER_SUCCESS)
 293                 t->result = f;
 294
 295         unit_log_result(UNIT(t), t->result == TIMER_SUCCESS, timer_result_to_string(t->result));
 296         timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
 297 }
 298
 299 static void timer_enter_elapsed(Timer *t, bool leave_around) {
 300         assert(t);
 301
 302         /* If a unit is marked with RemainAfterElapse=yes we leave it
 303          * around even after it elapsed once, so that starting it
 304          * later again does not necessarily mean immediate
 305          * retriggering. We unconditionally leave units with
 306          * TIMER_UNIT_ACTIVE or TIMER_UNIT_INACTIVE triggers around,
 307          * since they might be restarted automatically at any time
 308          * later on. */
 309
 310         if (t->remain_after_elapse || leave_around)
 311                 timer_set_state(t, TIMER_ELAPSED);
 312         else
 313                 timer_enter_dead(t, TIMER_SUCCESS);
 314 }
 315
 316 static void add_random(Timer *t, usec_t *v) {
 317         char s[FORMAT_TIMESPAN_MAX];
 318         usec_t add;
 319
 320         assert(t);
 321         assert(v);
 322
 323         if (t->random_usec == 0)
 324                 return;
 325         if (*v == USEC_INFINITY)
 326                 return;
 327
 328         add = random_u64() % t->random_usec;
 329
 330         if (*v + add < *v) /* overflow */
 331                 *v = (usec_t) -2; /* Highest possible value, that is not USEC_INFINITY */
 332         else
 333                 *v += add;
 334
 335         log_unit_debug(UNIT(t), "Adding %s random time.", format_timespan(s, sizeof(s), add, 0));
 336 }
 337
 338 static void timer_enter_waiting(Timer *t, bool time_change) {
 339         bool found_monotonic = false, found_realtime = false;
 340         bool leave_around = false;
 341         triple_timestamp ts;
 342         TimerValue *v;
 343         Unit *trigger;
 344         int r;
 345
 346         assert(t);
 347
 348         trigger = UNIT_TRIGGER(UNIT(t));
 349         if (!trigger) {
 350                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 351                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 352                 return;
 353         }
 354
 355         triple_timestamp_get(&ts);
 356         t->next_elapse_monotonic_or_boottime = t->next_elapse_realtime = 0;
 357
 358         LIST_FOREACH(value, v, t->values) {
 359                 if (v->disabled)
 360                         continue;
 361
 362                 if (v->base == TIMER_CALENDAR) {
 363                         usec_t b;
 364
 365                         /* If we know the last time this was
 366                          * triggered, schedule the job based relative
 367                          * to that. If we don't, just start from
 368                          * the activation time. */
 369
 370                         if (t->last_trigger.realtime > 0)
 371                                 b = t->last_trigger.realtime;
 372                         else {
 373                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 374                                         b = UNIT(t)->inactive_exit_timestamp.realtime;
 375                                 else
 376                                         b = ts.realtime;
 377                         }
 378
 379                         r = calendar_spec_next_usec(v->calendar_spec, b, &v->next_elapse);
 380                         if (r < 0)
 381                                 continue;
 382
 383                         /* To make the delay due to RandomizedDelaySec= work even at boot,
 384                          * if the scheduled time has already passed, set the time when systemd
 385                          * first started as the scheduled time.
 386                          * Also, we don't have to check t->persistent since the logic implicitly express true. */
 387                         if (v->next_elapse < UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].realtime)
 388                                 v->next_elapse = UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].realtime;
 389
 390                         if (!found_realtime)
 391                                 t->next_elapse_realtime = v->next_elapse;
 392                         else
 393                                 t->next_elapse_realtime = MIN(t->next_elapse_realtime, v->next_elapse);
 394
 395                         found_realtime = true;
 396
 397                 } else {
 398                         usec_t base;
 399
 400                         switch (v->base) {
 401
 402                         case TIMER_ACTIVE:
 403                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 404                                         base = UNIT(t)->inactive_exit_timestamp.monotonic;
 405                                 else
 406                                         base = ts.monotonic;
 407                                 break;
 408
 409                         case TIMER_BOOT:
 410                                 if (detect_container() <= 0) {
 411                                         /* CLOCK_MONOTONIC equals the uptime on Linux */
 412                                         base = 0;
 413                                         break;
 414                                 }
 415                                 /* In a container we don't want to include the time the host
 416                                  * was already up when the container started, so count from
 417                                  * our own startup. */
 418                                 _fallthrough_;
 419                         case TIMER_STARTUP:
 420                                 base = UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].monotonic;
 421                                 break;
 422
 423                         case TIMER_UNIT_ACTIVE:
 424                                 leave_around = true;
 425                                 base = trigger->inactive_exit_timestamp.monotonic;
 426
 427                                 if (base <= 0)
 428                                         base = t->last_trigger.monotonic;
 429
 430                                 if (base <= 0)
 431                                         continue;
 432                                 base = MAX(base, t->last_trigger.monotonic);
 433
 434                                 break;
 435
 436                         case TIMER_UNIT_INACTIVE:
 437                                 leave_around = true;
 438                                 base = trigger->inactive_enter_timestamp.monotonic;
 439
 440                                 if (base <= 0)
 441                                         base = t->last_trigger.monotonic;
 442
 443                                 if (base <= 0)
 444                                         continue;
 445                                 base = MAX(base, t->last_trigger.monotonic);
 446
 447                                 break;
 448
 449                         default:
 450                                 assert_not_reached("Unknown timer base");
 451                         }
 452
 453                         v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
 454
 455                         if (dual_timestamp_is_set(&t->last_trigger) &&
 456                             !time_change &&
 457                             v->next_elapse < triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)) &&
 458                             IN_SET(v->base, TIMER_ACTIVE, TIMER_BOOT, TIMER_STARTUP)) {
 459                                 /* This is a one time trigger, disable it now */
 460                                 v->disabled = true;
 461                                 continue;
 462                         }
 463
 464                         if (!found_monotonic)
 465                                 t->next_elapse_monotonic_or_boottime = v->next_elapse;
 466                         else
 467                                 t->next_elapse_monotonic_or_boottime = MIN(t->next_elapse_monotonic_or_boottime, v->next_elapse);
 468
 469                         found_monotonic = true;
 470                 }
 471         }
 472
 473         if (!found_monotonic && !found_realtime) {
 474                 log_unit_debug(UNIT(t), "Timer is elapsed.");
 475                 timer_enter_elapsed(t, leave_around);
 476                 return;
 477         }
 478
 479         if (found_monotonic) {
 480                 char buf[FORMAT_TIMESPAN_MAX];
 481                 usec_t left;
 482
 483                 add_random(t, &t->next_elapse_monotonic_or_boottime);
 484
 485                 left = usec_sub_unsigned(t->next_elapse_monotonic_or_boottime, triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)));
 486                 log_unit_debug(UNIT(t), "Monotonic timer elapses in %s.", format_timespan(buf, sizeof(buf), left, 0));
 487
 488                 if (t->monotonic_event_source) {
 489                         r = sd_event_source_set_time(t->monotonic_event_source, t->next_elapse_monotonic_or_boottime);
 490                         if (r < 0)
 491                                 goto fail;
 492
 493                         r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_ONESHOT);
 494                         if (r < 0)
 495                                 goto fail;
 496                 } else {
 497
 498                         r = sd_event_add_time(
 499                                         UNIT(t)->manager->event,
 500                                         &t->monotonic_event_source,
 501                                         t->wake_system ? CLOCK_BOOTTIME_ALARM : CLOCK_MONOTONIC,
 502                                         t->next_elapse_monotonic_or_boottime, t->accuracy_usec,
 503                                         timer_dispatch, t);
 504                         if (r < 0)
 505                                 goto fail;
 506
 507                         (void) sd_event_source_set_description(t->monotonic_event_source, "timer-monotonic");
 508                 }
 509
 510         } else if (t->monotonic_event_source) {
 511
 512                 r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_OFF);
 513                 if (r < 0)
 514                         goto fail;
 515         }
 516
 517         if (found_realtime) {
 518                 char buf[FORMAT_TIMESTAMP_MAX];
 519
 520                 add_random(t, &t->next_elapse_realtime);
 521
 522                 log_unit_debug(UNIT(t), "Realtime timer elapses at %s.", format_timestamp(buf, sizeof(buf), t->next_elapse_realtime));
 523
 524                 if (t->realtime_event_source) {
 525                         r = sd_event_source_set_time(t->realtime_event_source, t->next_elapse_realtime);
 526                         if (r < 0)
 527                                 goto fail;
 528
 529                         r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_ONESHOT);
 530                         if (r < 0)
 531                                 goto fail;
 532                 } else {
 533                         r = sd_event_add_time(
 534                                         UNIT(t)->manager->event,
 535                                         &t->realtime_event_source,
 536                                         t->wake_system ? CLOCK_REALTIME_ALARM : CLOCK_REALTIME,
 537                                         t->next_elapse_realtime, t->accuracy_usec,
 538                                         timer_dispatch, t);
 539                         if (r < 0)
 540                                 goto fail;
 541
 542                         (void) sd_event_source_set_description(t->realtime_event_source, "timer-realtime");
 543                 }
 544
 545         } else if (t->realtime_event_source) {
 546
 547                 r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_OFF);
 548                 if (r < 0)
 549                         goto fail;
 550         }
 551
 552         timer_set_state(t, TIMER_WAITING);
 553         return;
 554
 555 fail:
 556         log_unit_warning_errno(UNIT(t), r, "Failed to enter waiting state: %m");
 557         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 558 }
 559
 560 static void timer_enter_running(Timer *t) {
 561         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 562         Unit *trigger;
 563         int r;
 564
 565         assert(t);
 566
 567         /* Don't start job if we are supposed to go down */
 568         if (unit_stop_pending(UNIT(t)))
 569                 return;
 570
 571         trigger = UNIT_TRIGGER(UNIT(t));
 572         if (!trigger) {
 573                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 574                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 575                 return;
 576         }
 577
 578         r = manager_add_job(UNIT(t)->manager, JOB_START, trigger, JOB_REPLACE, &error, NULL);
 579         if (r < 0)
 580                 goto fail;
 581
 582         dual_timestamp_get(&t->last_trigger);
 583
 584         if (t->stamp_path)
 585                 touch_file(t->stamp_path, true, t->last_trigger.realtime, UID_INVALID, GID_INVALID, MODE_INVALID);
 586
 587         timer_set_state(t, TIMER_RUNNING);
 588         return;
 589
 590 fail:
 591         log_unit_warning(UNIT(t), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
 592         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 593 }
 594
 595 static int timer_start(Unit *u) {
 596         Timer *t = TIMER(u);
 597         TimerValue *v;
 598         Unit *trigger;
 599         int r;
 600
 601         assert(t);
 602         assert(IN_SET(t->state, TIMER_DEAD, TIMER_FAILED));
 603
 604         trigger = UNIT_TRIGGER(u);
 605         if (!trigger || trigger->load_state != UNIT_LOADED) {
 606                 log_unit_error(u, "Refusing to start, unit to trigger not loaded.");
 607                 return -ENOENT;
 608         }
 609
 610         r = unit_test_start_limit(u);
 611         if (r < 0) {
 612                 timer_enter_dead(t, TIMER_FAILURE_START_LIMIT_HIT);
 613                 return r;
 614         }
 615
 616         r = unit_acquire_invocation_id(u);
 617         if (r < 0)
 618                 return r;
 619
 620         t->last_trigger = DUAL_TIMESTAMP_NULL;
 621
 622         /* Reenable all timers that depend on unit activation time */
 623         LIST_FOREACH(value, v, t->values)
 624                 if (v->base == TIMER_ACTIVE)
 625                         v->disabled = false;
 626
 627         if (t->stamp_path) {
 628                 struct stat st;
 629
 630                 if (stat(t->stamp_path, &st) >= 0) {
 631                         usec_t ft;
 632
 633                         /* Load the file timestamp, but only if it is actually in the past. If it is in the future,
 634                          * something is wrong with the system clock. */
 635
 636                         ft = timespec_load(&st.st_mtim);
 637                         if (ft < now(CLOCK_REALTIME))
 638                                 t->last_trigger.realtime = ft;
 639                         else {
 640                                 char z[FORMAT_TIMESTAMP_MAX];
 641
 642                                 log_unit_warning(u, "Not using persistent file timestamp %s as it is in the future.",
 643                                                  format_timestamp(z, sizeof(z), ft));
 644                         }
 645
 646                 } else if (errno == ENOENT)
 647                         /* The timer has never run before,
 648                          * make sure a stamp file exists.
 649                          */
 650                         (void) touch_file(t->stamp_path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
 651         }
 652
 653         t->result = TIMER_SUCCESS;
 654         timer_enter_waiting(t, false);
 655         return 1;
 656 }
 657
 658 static int timer_stop(Unit *u) {
 659         Timer *t = TIMER(u);
 660
 661         assert(t);
 662         assert(IN_SET(t->state, TIMER_WAITING, TIMER_RUNNING, TIMER_ELAPSED));
 663
 664         timer_enter_dead(t, TIMER_SUCCESS);
 665         return 1;
 666 }
 667
 668 static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
 669         Timer *t = TIMER(u);
 670
 671         assert(u);
 672         assert(f);
 673         assert(fds);
 674
 675         (void) serialize_item(f, "state", timer_state_to_string(t->state));
 676         (void) serialize_item(f, "result", timer_result_to_string(t->result));
 677
 678         if (t->last_trigger.realtime > 0)
 679                 (void) serialize_usec(f, "last-trigger-realtime", t->last_trigger.realtime);
 680
 681         if (t->last_trigger.monotonic > 0)
 682                 (void) serialize_usec(f, "last-trigger-monotonic", t->last_trigger.monotonic);
 683
 684         return 0;
 685 }
 686
 687 static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 688         Timer *t = TIMER(u);
 689
 690         assert(u);
 691         assert(key);
 692         assert(value);
 693         assert(fds);
 694
 695         if (streq(key, "state")) {
 696                 TimerState state;
 697
 698                 state = timer_state_from_string(value);
 699                 if (state < 0)
 700                         log_unit_debug(u, "Failed to parse state value: %s", value);
 701                 else
 702                         t->deserialized_state = state;
 703
 704         } else if (streq(key, "result")) {
 705                 TimerResult f;
 706
 707                 f = timer_result_from_string(value);
 708                 if (f < 0)
 709                         log_unit_debug(u, "Failed to parse result value: %s", value);
 710                 else if (f != TIMER_SUCCESS)
 711                         t->result = f;
 712
 713         } else if (streq(key, "last-trigger-realtime"))
 714                 (void) deserialize_usec(value, &t->last_trigger.realtime);
 715         else if (streq(key, "last-trigger-monotonic"))
 716                 (void) deserialize_usec(value, &t->last_trigger.monotonic);
 717         else
 718                 log_unit_debug(u, "Unknown serialization key: %s", key);
 719
 720         return 0;
 721 }
 722
 723 _pure_ static UnitActiveState timer_active_state(Unit *u) {
 724         assert(u);
 725
 726         return state_translation_table[TIMER(u)->state];
 727 }
 728
 729 _pure_ static const char *timer_sub_state_to_string(Unit *u) {
 730         assert(u);
 731
 732         return timer_state_to_string(TIMER(u)->state);
 733 }
 734
 735 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata) {
 736         Timer *t = TIMER(userdata);
 737
 738         assert(t);
 739
 740         if (t->state != TIMER_WAITING)
 741                 return 0;
 742
 743         log_unit_debug(UNIT(t), "Timer elapsed.");
 744         timer_enter_running(t);
 745         return 0;
 746 }
 747
 748 static void timer_trigger_notify(Unit *u, Unit *other) {
 749         Timer *t = TIMER(u);
 750         TimerValue *v;
 751
 752         assert(u);
 753         assert(other);
 754
 755         if (other->load_state != UNIT_LOADED)
 756                 return;
 757
 758         /* Reenable all timers that depend on unit state */
 759         LIST_FOREACH(value, v, t->values)
 760                 if (IN_SET(v->base, TIMER_UNIT_ACTIVE, TIMER_UNIT_INACTIVE))
 761                         v->disabled = false;
 762
 763         switch (t->state) {
 764
 765         case TIMER_WAITING:
 766         case TIMER_ELAPSED:
 767
 768                 /* Recalculate sleep time */
 769                 timer_enter_waiting(t, false);
 770                 break;
 771
 772         case TIMER_RUNNING:
 773
 774                 if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
 775                         log_unit_debug(UNIT(t), "Got notified about unit deactivation.");
 776                         timer_enter_waiting(t, false);
 777                 }
 778                 break;
 779
 780         case TIMER_DEAD:
 781         case TIMER_FAILED:
 782                 break;
 783
 784         default:
 785                 assert_not_reached("Unknown timer state");
 786         }
 787 }
 788
 789 static void timer_reset_failed(Unit *u) {
 790         Timer *t = TIMER(u);
 791
 792         assert(t);
 793
 794         if (t->state == TIMER_FAILED)
 795                 timer_set_state(t, TIMER_DEAD);
 796
 797         t->result = TIMER_SUCCESS;
 798 }
 799
 800 static void timer_time_change(Unit *u) {
 801         Timer *t = TIMER(u);
 802         usec_t ts;
 803
 804         assert(u);
 805
 806         if (t->state != TIMER_WAITING)
 807                 return;
 808
 809         /* If we appear to have triggered in the future, the system clock must
 810          * have been set backwards.  So let's rewind our own clock and allow
 811          * the future trigger(s) to happen again :).  Exactly the same as when
 812          * you start a timer unit with Persistent=yes. */
 813         ts = now(CLOCK_REALTIME);
 814         if (t->last_trigger.realtime > ts)
 815                 t->last_trigger.realtime = ts;
 816
 817         log_unit_debug(u, "Time change, recalculating next elapse.");
 818         timer_enter_waiting(t, true);
 819 }
 820
 821 static void timer_timezone_change(Unit *u) {
 822         Timer *t = TIMER(u);
 823
 824         assert(u);
 825
 826         if (t->state != TIMER_WAITING)
 827                 return;
 828
 829         log_unit_debug(u, "Timezone change, recalculating next elapse.");
 830         timer_enter_waiting(t, false);
 831 }
 832
 833 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
 834         [TIMER_ACTIVE] = "OnActiveSec",
 835         [TIMER_BOOT] = "OnBootSec",
 836         [TIMER_STARTUP] = "OnStartupSec",
 837         [TIMER_UNIT_ACTIVE] = "OnUnitActiveSec",
 838         [TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec",
 839         [TIMER_CALENDAR] = "OnCalendar"
 840 };
 841
 842 DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
 843
 844 static const char* const timer_result_table[_TIMER_RESULT_MAX] = {
 845         [TIMER_SUCCESS] = "success",
 846         [TIMER_FAILURE_RESOURCES] = "resources",
 847         [TIMER_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
 848 };
 849
 850 DEFINE_STRING_TABLE_LOOKUP(timer_result, TimerResult);
 851
 852 const UnitVTable timer_vtable = {
 853         .object_size = sizeof(Timer),
 854
 855         .sections =
 856                 "Unit\0"
 857                 "Timer\0"
 858                 "Install\0",
 859         .private_section = "Timer",
 860
 861         .init = timer_init,
 862         .done = timer_done,
 863         .load = timer_load,
 864
 865         .coldplug = timer_coldplug,
 866
 867         .dump = timer_dump,
 868
 869         .start = timer_start,
 870         .stop = timer_stop,
 871
 872         .serialize = timer_serialize,
 873         .deserialize_item = timer_deserialize_item,
 874
 875         .active_state = timer_active_state,
 876         .sub_state_to_string = timer_sub_state_to_string,
 877
 878         .trigger_notify = timer_trigger_notify,
 879
 880         .reset_failed = timer_reset_failed,
 881         .time_change = timer_time_change,
 882         .timezone_change = timer_timezone_change,
 883
 884         .bus_vtable = bus_timer_vtable,
 885         .bus_set_property = bus_timer_set_property,
 886
 887         .can_transient = true,
 888 };