src/core/timer.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <sys/stat.h>
   4 #include <sys/types.h>
   5 #include <unistd.h>
   6
   7 #include <errno.h>
   8
   9 #include "alloc-util.h"
  10 #include "bus-error.h"
  11 #include "bus-util.h"
  12 #include "dbus-timer.h"
  13 #include "dbus-unit.h"
  14 #include "fs-util.h"
  15 #include "parse-util.h"
  16 #include "random-util.h"
  17 #include "serialize.h"
  18 #include "special.h"
  19 #include "string-table.h"
  20 #include "string-util.h"
  21 #include "timer.h"
  22 #include "unit-name.h"
  23 #include "unit.h"
  24 #include "user-util.h"
  25 #include "virt.h"
  26
  27 static const UnitActiveState state_translation_table[_TIMER_STATE_MAX] = {
  28         [TIMER_DEAD] = UNIT_INACTIVE,
  29         [TIMER_WAITING] = UNIT_ACTIVE,
  30         [TIMER_RUNNING] = UNIT_ACTIVE,
  31         [TIMER_ELAPSED] = UNIT_ACTIVE,
  32         [TIMER_FAILED] = UNIT_FAILED
  33 };
  34
  35 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata);
  36
  37 static void timer_init(Unit *u) {
  38         Timer *t = TIMER(u);
  39
  40         assert(u);
  41         assert(u->load_state == UNIT_STUB);
  42
  43         t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
  44         t->next_elapse_realtime = USEC_INFINITY;
  45         t->accuracy_usec = u->manager->default_timer_accuracy_usec;
  46         t->remain_after_elapse = true;
  47 }
  48
  49 void timer_free_values(Timer *t) {
  50         TimerValue *v;
  51
  52         assert(t);
  53
  54         while ((v = t->values)) {
  55                 LIST_REMOVE(value, t->values, v);
  56                 calendar_spec_free(v->calendar_spec);
  57                 free(v);
  58         }
  59 }
  60
  61 static void timer_done(Unit *u) {
  62         Timer *t = TIMER(u);
  63
  64         assert(t);
  65
  66         timer_free_values(t);
  67
  68         t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
  69         t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
  70
  71         free(t->stamp_path);
  72 }
  73
  74 static int timer_verify(Timer *t) {
  75         assert(t);
  76         assert(UNIT(t)->load_state == UNIT_LOADED);
  77
  78         if (!t->values && !t->on_clock_change && !t->on_timezone_change) {
  79                 log_unit_error(UNIT(t), "Timer unit lacks value setting. Refusing.");
  80                 return -ENOEXEC;
  81         }
  82
  83         return 0;
  84 }
  85
  86 static int timer_add_default_dependencies(Timer *t) {
  87         int r;
  88         TimerValue *v;
  89
  90         assert(t);
  91
  92         if (!UNIT(t)->default_dependencies)
  93                 return 0;
  94
  95         r = unit_add_dependency_by_name(UNIT(t), UNIT_BEFORE, SPECIAL_TIMERS_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  96         if (r < 0)
  97                 return r;
  98
  99         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
 100                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
 101                 if (r < 0)
 102                         return r;
 103
 104                 LIST_FOREACH(value, v, t->values) {
 105                         if (v->base == TIMER_CALENDAR) {
 106                                 r = unit_add_dependency_by_name(UNIT(t), UNIT_AFTER, SPECIAL_TIME_SYNC_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
 107                                 if (r < 0)
 108                                         return r;
 109                                 break;
 110                         }
 111                 }
 112         }
 113
 114         return unit_add_two_dependencies_by_name(UNIT(t), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
 115 }
 116
 117 static int timer_add_trigger_dependencies(Timer *t) {
 118         Unit *x;
 119         int r;
 120
 121         assert(t);
 122
 123         if (!hashmap_isempty(UNIT(t)->dependencies[UNIT_TRIGGERS]))
 124                 return 0;
 125
 126         r = unit_load_related_unit(UNIT(t), ".service", &x);
 127         if (r < 0)
 128                 return r;
 129
 130         return unit_add_two_dependencies(UNIT(t), UNIT_BEFORE, UNIT_TRIGGERS, x, true, UNIT_DEPENDENCY_IMPLICIT);
 131 }
 132
 133 static int timer_setup_persistent(Timer *t) {
 134         int r;
 135
 136         assert(t);
 137
 138         if (!t->persistent)
 139                 return 0;
 140
 141         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
 142
 143                 r = unit_require_mounts_for(UNIT(t), "/var/lib/systemd/timers", UNIT_DEPENDENCY_FILE);
 144                 if (r < 0)
 145                         return r;
 146
 147                 t->stamp_path = strjoin("/var/lib/systemd/timers/stamp-", UNIT(t)->id);
 148         } else {
 149                 const char *e;
 150
 151                 e = getenv("XDG_DATA_HOME");
 152                 if (e)
 153                         t->stamp_path = strjoin(e, "/systemd/timers/stamp-", UNIT(t)->id);
 154                 else {
 155
 156                         _cleanup_free_ char *h = NULL;
 157
 158                         r = get_home_dir(&h);
 159                         if (r < 0)
 160                                 return log_unit_error_errno(UNIT(t), r, "Failed to determine home directory: %m");
 161
 162                         t->stamp_path = strjoin(h, "/.local/share/systemd/timers/stamp-", UNIT(t)->id);
 163                 }
 164         }
 165
 166         if (!t->stamp_path)
 167                 return log_oom();
 168
 169         return 0;
 170 }
 171
 172 static int timer_load(Unit *u) {
 173         Timer *t = TIMER(u);
 174         int r;
 175
 176         assert(u);
 177         assert(u->load_state == UNIT_STUB);
 178
 179         r = unit_load_fragment_and_dropin(u, true);
 180         if (r < 0)
 181                 return r;
 182
 183         if (u->load_state != UNIT_LOADED)
 184                 return 0;
 185
 186         /* This is a new unit? Then let's add in some extras */
 187         r = timer_add_trigger_dependencies(t);
 188         if (r < 0)
 189                 return r;
 190
 191         r = timer_setup_persistent(t);
 192         if (r < 0)
 193                 return r;
 194
 195         r = timer_add_default_dependencies(t);
 196         if (r < 0)
 197                 return r;
 198
 199         return timer_verify(t);
 200 }
 201
 202 static void timer_dump(Unit *u, FILE *f, const char *prefix) {
 203         char buf[FORMAT_TIMESPAN_MAX];
 204         Timer *t = TIMER(u);
 205         Unit *trigger;
 206         TimerValue *v;
 207
 208         trigger = UNIT_TRIGGER(u);
 209
 210         fprintf(f,
 211                 "%sTimer State: %s\n"
 212                 "%sResult: %s\n"
 213                 "%sUnit: %s\n"
 214                 "%sPersistent: %s\n"
 215                 "%sWakeSystem: %s\n"
 216                 "%sAccuracy: %s\n"
 217                 "%sRemainAfterElapse: %s\n"
 218                 "%sOnClockChange: %s\n"
 219                 "%sOnTimeZoneChange: %s\n",
 220                 prefix, timer_state_to_string(t->state),
 221                 prefix, timer_result_to_string(t->result),
 222                 prefix, trigger ? trigger->id : "n/a",
 223                 prefix, yes_no(t->persistent),
 224                 prefix, yes_no(t->wake_system),
 225                 prefix, format_timespan(buf, sizeof(buf), t->accuracy_usec, 1),
 226                 prefix, yes_no(t->remain_after_elapse),
 227                 prefix, yes_no(t->on_clock_change),
 228                 prefix, yes_no(t->on_timezone_change));
 229
 230         LIST_FOREACH(value, v, t->values) {
 231
 232                 if (v->base == TIMER_CALENDAR) {
 233                         _cleanup_free_ char *p = NULL;
 234
 235                         (void) calendar_spec_to_string(v->calendar_spec, &p);
 236
 237                         fprintf(f,
 238                                 "%s%s: %s\n",
 239                                 prefix,
 240                                 timer_base_to_string(v->base),
 241                                 strna(p));
 242                 } else  {
 243                         char timespan1[FORMAT_TIMESPAN_MAX];
 244
 245                         fprintf(f,
 246                                 "%s%s: %s\n",
 247                                 prefix,
 248                                 timer_base_to_string(v->base),
 249                                 format_timespan(timespan1, sizeof(timespan1), v->value, 0));
 250                 }
 251         }
 252 }
 253
 254 static void timer_set_state(Timer *t, TimerState state) {
 255         TimerState old_state;
 256         assert(t);
 257
 258         if (t->state != state)
 259                 bus_unit_send_pending_change_signal(UNIT(t), false);
 260
 261         old_state = t->state;
 262         t->state = state;
 263
 264         if (state != TIMER_WAITING) {
 265                 t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
 266                 t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
 267                 t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
 268                 t->next_elapse_realtime = USEC_INFINITY;
 269         }
 270
 271         if (state != old_state)
 272                 log_unit_debug(UNIT(t), "Changed %s -> %s", timer_state_to_string(old_state), timer_state_to_string(state));
 273
 274         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], 0);
 275 }
 276
 277 static void timer_enter_waiting(Timer *t, bool time_change);
 278
 279 static int timer_coldplug(Unit *u) {
 280         Timer *t = TIMER(u);
 281
 282         assert(t);
 283         assert(t->state == TIMER_DEAD);
 284
 285         if (t->deserialized_state == t->state)
 286                 return 0;
 287
 288         if (t->deserialized_state == TIMER_WAITING)
 289                 timer_enter_waiting(t, false);
 290         else
 291                 timer_set_state(t, t->deserialized_state);
 292
 293         return 0;
 294 }
 295
 296 static void timer_enter_dead(Timer *t, TimerResult f) {
 297         assert(t);
 298
 299         if (t->result == TIMER_SUCCESS)
 300                 t->result = f;
 301
 302         unit_log_result(UNIT(t), t->result == TIMER_SUCCESS, timer_result_to_string(t->result));
 303         timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
 304 }
 305
 306 static void timer_enter_elapsed(Timer *t, bool leave_around) {
 307         assert(t);
 308
 309         /* If a unit is marked with RemainAfterElapse=yes we leave it
 310          * around even after it elapsed once, so that starting it
 311          * later again does not necessarily mean immediate
 312          * retriggering. We unconditionally leave units with
 313          * TIMER_UNIT_ACTIVE or TIMER_UNIT_INACTIVE triggers around,
 314          * since they might be restarted automatically at any time
 315          * later on. */
 316
 317         if (t->remain_after_elapse || leave_around)
 318                 timer_set_state(t, TIMER_ELAPSED);
 319         else
 320                 timer_enter_dead(t, TIMER_SUCCESS);
 321 }
 322
 323 static void add_random(Timer *t, usec_t *v) {
 324         char s[FORMAT_TIMESPAN_MAX];
 325         usec_t add;
 326
 327         assert(t);
 328         assert(v);
 329
 330         if (t->random_usec == 0)
 331                 return;
 332         if (*v == USEC_INFINITY)
 333                 return;
 334
 335         add = random_u64() % t->random_usec;
 336
 337         if (*v + add < *v) /* overflow */
 338                 *v = (usec_t) -2; /* Highest possible value, that is not USEC_INFINITY */
 339         else
 340                 *v += add;
 341
 342         log_unit_debug(UNIT(t), "Adding %s random time.", format_timespan(s, sizeof(s), add, 0));
 343 }
 344
 345 static void timer_enter_waiting(Timer *t, bool time_change) {
 346         bool found_monotonic = false, found_realtime = false;
 347         bool leave_around = false;
 348         triple_timestamp ts;
 349         TimerValue *v;
 350         Unit *trigger;
 351         int r;
 352
 353         assert(t);
 354
 355         trigger = UNIT_TRIGGER(UNIT(t));
 356         if (!trigger) {
 357                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 358                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 359                 return;
 360         }
 361
 362         triple_timestamp_get(&ts);
 363         t->next_elapse_monotonic_or_boottime = t->next_elapse_realtime = 0;
 364
 365         LIST_FOREACH(value, v, t->values) {
 366                 if (v->disabled)
 367                         continue;
 368
 369                 if (v->base == TIMER_CALENDAR) {
 370                         usec_t b;
 371
 372                         /* If we know the last time this was
 373                          * triggered, schedule the job based relative
 374                          * to that. If we don't, just start from
 375                          * the activation time. */
 376
 377                         if (t->last_trigger.realtime > 0)
 378                                 b = t->last_trigger.realtime;
 379                         else {
 380                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 381                                         b = UNIT(t)->inactive_exit_timestamp.realtime;
 382                                 else
 383                                         b = ts.realtime;
 384                         }
 385
 386                         r = calendar_spec_next_usec(v->calendar_spec, b, &v->next_elapse);
 387                         if (r < 0)
 388                                 continue;
 389
 390                         /* To make the delay due to RandomizedDelaySec= work even at boot,
 391                          * if the scheduled time has already passed, set the time when systemd
 392                          * first started as the scheduled time.
 393                          * Also, we don't have to check t->persistent since the logic implicitly express true. */
 394                         if (v->next_elapse < UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].realtime)
 395                                 v->next_elapse = UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].realtime;
 396
 397                         if (!found_realtime)
 398                                 t->next_elapse_realtime = v->next_elapse;
 399                         else
 400                                 t->next_elapse_realtime = MIN(t->next_elapse_realtime, v->next_elapse);
 401
 402                         found_realtime = true;
 403
 404                 } else {
 405                         usec_t base;
 406
 407                         switch (v->base) {
 408
 409                         case TIMER_ACTIVE:
 410                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 411                                         base = UNIT(t)->inactive_exit_timestamp.monotonic;
 412                                 else
 413                                         base = ts.monotonic;
 414                                 break;
 415
 416                         case TIMER_BOOT:
 417                                 if (detect_container() <= 0) {
 418                                         /* CLOCK_MONOTONIC equals the uptime on Linux */
 419                                         base = 0;
 420                                         break;
 421                                 }
 422                                 /* In a container we don't want to include the time the host
 423                                  * was already up when the container started, so count from
 424                                  * our own startup. */
 425                                 _fallthrough_;
 426                         case TIMER_STARTUP:
 427                                 base = UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].monotonic;
 428                                 break;
 429
 430                         case TIMER_UNIT_ACTIVE:
 431                                 leave_around = true;
 432                                 base = MAX(trigger->inactive_exit_timestamp.monotonic, t->last_trigger.monotonic);
 433                                 if (base <= 0)
 434                                         continue;
 435                                 break;
 436
 437                         case TIMER_UNIT_INACTIVE:
 438                                 leave_around = true;
 439                                 base = MAX(trigger->inactive_enter_timestamp.monotonic, t->last_trigger.monotonic);
 440                                 if (base <= 0)
 441                                         continue;
 442                                 break;
 443
 444                         default:
 445                                 assert_not_reached("Unknown timer base");
 446                         }
 447
 448                         v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
 449
 450                         if (dual_timestamp_is_set(&t->last_trigger) &&
 451                             !time_change &&
 452                             v->next_elapse < triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)) &&
 453                             IN_SET(v->base, TIMER_ACTIVE, TIMER_BOOT, TIMER_STARTUP)) {
 454                                 /* This is a one time trigger, disable it now */
 455                                 v->disabled = true;
 456                                 continue;
 457                         }
 458
 459                         if (!found_monotonic)
 460                                 t->next_elapse_monotonic_or_boottime = v->next_elapse;
 461                         else
 462                                 t->next_elapse_monotonic_or_boottime = MIN(t->next_elapse_monotonic_or_boottime, v->next_elapse);
 463
 464                         found_monotonic = true;
 465                 }
 466         }
 467
 468         if (!found_monotonic && !found_realtime && !t->on_timezone_change && !t->on_clock_change) {
 469                 log_unit_debug(UNIT(t), "Timer is elapsed.");
 470                 timer_enter_elapsed(t, leave_around);
 471                 return;
 472         }
 473
 474         if (found_monotonic) {
 475                 char buf[FORMAT_TIMESPAN_MAX];
 476                 usec_t left;
 477
 478                 add_random(t, &t->next_elapse_monotonic_or_boottime);
 479
 480                 left = usec_sub_unsigned(t->next_elapse_monotonic_or_boottime, triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)));
 481                 log_unit_debug(UNIT(t), "Monotonic timer elapses in %s.", format_timespan(buf, sizeof(buf), left, 0));
 482
 483                 if (t->monotonic_event_source) {
 484                         r = sd_event_source_set_time(t->monotonic_event_source, t->next_elapse_monotonic_or_boottime);
 485                         if (r < 0)
 486                                 goto fail;
 487
 488                         r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_ONESHOT);
 489                         if (r < 0)
 490                                 goto fail;
 491                 } else {
 492
 493                         r = sd_event_add_time(
 494                                         UNIT(t)->manager->event,
 495                                         &t->monotonic_event_source,
 496                                         t->wake_system ? CLOCK_BOOTTIME_ALARM : CLOCK_MONOTONIC,
 497                                         t->next_elapse_monotonic_or_boottime, t->accuracy_usec,
 498                                         timer_dispatch, t);
 499                         if (r < 0)
 500                                 goto fail;
 501
 502                         (void) sd_event_source_set_description(t->monotonic_event_source, "timer-monotonic");
 503                 }
 504
 505         } else if (t->monotonic_event_source) {
 506
 507                 r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_OFF);
 508                 if (r < 0)
 509                         goto fail;
 510         }
 511
 512         if (found_realtime) {
 513                 char buf[FORMAT_TIMESTAMP_MAX];
 514
 515                 add_random(t, &t->next_elapse_realtime);
 516
 517                 log_unit_debug(UNIT(t), "Realtime timer elapses at %s.", format_timestamp(buf, sizeof(buf), t->next_elapse_realtime));
 518
 519                 if (t->realtime_event_source) {
 520                         r = sd_event_source_set_time(t->realtime_event_source, t->next_elapse_realtime);
 521                         if (r < 0)
 522                                 goto fail;
 523
 524                         r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_ONESHOT);
 525                         if (r < 0)
 526                                 goto fail;
 527                 } else {
 528                         r = sd_event_add_time(
 529                                         UNIT(t)->manager->event,
 530                                         &t->realtime_event_source,
 531                                         t->wake_system ? CLOCK_REALTIME_ALARM : CLOCK_REALTIME,
 532                                         t->next_elapse_realtime, t->accuracy_usec,
 533                                         timer_dispatch, t);
 534                         if (r < 0)
 535                                 goto fail;
 536
 537                         (void) sd_event_source_set_description(t->realtime_event_source, "timer-realtime");
 538                 }
 539
 540         } else if (t->realtime_event_source) {
 541
 542                 r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_OFF);
 543                 if (r < 0)
 544                         goto fail;
 545         }
 546
 547         timer_set_state(t, TIMER_WAITING);
 548         return;
 549
 550 fail:
 551         log_unit_warning_errno(UNIT(t), r, "Failed to enter waiting state: %m");
 552         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 553 }
 554
 555 static void timer_enter_running(Timer *t) {
 556         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 557         Unit *trigger;
 558         int r;
 559
 560         assert(t);
 561
 562         /* Don't start job if we are supposed to go down */
 563         if (unit_stop_pending(UNIT(t)))
 564                 return;
 565
 566         trigger = UNIT_TRIGGER(UNIT(t));
 567         if (!trigger) {
 568                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 569                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 570                 return;
 571         }
 572
 573         r = manager_add_job(UNIT(t)->manager, JOB_START, trigger, JOB_REPLACE, NULL, &error, NULL);
 574         if (r < 0)
 575                 goto fail;
 576
 577         dual_timestamp_get(&t->last_trigger);
 578
 579         if (t->stamp_path)
 580                 touch_file(t->stamp_path, true, t->last_trigger.realtime, UID_INVALID, GID_INVALID, MODE_INVALID);
 581
 582         timer_set_state(t, TIMER_RUNNING);
 583         return;
 584
 585 fail:
 586         log_unit_warning(UNIT(t), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
 587         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 588 }
 589
 590 static int timer_start(Unit *u) {
 591         Timer *t = TIMER(u);
 592         TimerValue *v;
 593         int r;
 594
 595         assert(t);
 596         assert(IN_SET(t->state, TIMER_DEAD, TIMER_FAILED));
 597
 598         r = unit_test_trigger_loaded(u);
 599         if (r < 0)
 600                 return r;
 601
 602         r = unit_test_start_limit(u);
 603         if (r < 0) {
 604                 timer_enter_dead(t, TIMER_FAILURE_START_LIMIT_HIT);
 605                 return r;
 606         }
 607
 608         r = unit_acquire_invocation_id(u);
 609         if (r < 0)
 610                 return r;
 611
 612         t->last_trigger = DUAL_TIMESTAMP_NULL;
 613
 614         /* Reenable all timers that depend on unit activation time */
 615         LIST_FOREACH(value, v, t->values)
 616                 if (v->base == TIMER_ACTIVE)
 617                         v->disabled = false;
 618
 619         if (t->stamp_path) {
 620                 struct stat st;
 621
 622                 if (stat(t->stamp_path, &st) >= 0) {
 623                         usec_t ft;
 624
 625                         /* Load the file timestamp, but only if it is actually in the past. If it is in the future,
 626                          * something is wrong with the system clock. */
 627
 628                         ft = timespec_load(&st.st_mtim);
 629                         if (ft < now(CLOCK_REALTIME))
 630                                 t->last_trigger.realtime = ft;
 631                         else {
 632                                 char z[FORMAT_TIMESTAMP_MAX];
 633
 634                                 log_unit_warning(u, "Not using persistent file timestamp %s as it is in the future.",
 635                                                  format_timestamp(z, sizeof(z), ft));
 636                         }
 637
 638                 } else if (errno == ENOENT)
 639                         /* The timer has never run before,
 640                          * make sure a stamp file exists.
 641                          */
 642                         (void) touch_file(t->stamp_path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
 643         }
 644
 645         t->result = TIMER_SUCCESS;
 646         timer_enter_waiting(t, false);
 647         return 1;
 648 }
 649
 650 static int timer_stop(Unit *u) {
 651         Timer *t = TIMER(u);
 652
 653         assert(t);
 654         assert(IN_SET(t->state, TIMER_WAITING, TIMER_RUNNING, TIMER_ELAPSED));
 655
 656         timer_enter_dead(t, TIMER_SUCCESS);
 657         return 1;
 658 }
 659
 660 static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
 661         Timer *t = TIMER(u);
 662
 663         assert(u);
 664         assert(f);
 665         assert(fds);
 666
 667         (void) serialize_item(f, "state", timer_state_to_string(t->state));
 668         (void) serialize_item(f, "result", timer_result_to_string(t->result));
 669
 670         if (t->last_trigger.realtime > 0)
 671                 (void) serialize_usec(f, "last-trigger-realtime", t->last_trigger.realtime);
 672
 673         if (t->last_trigger.monotonic > 0)
 674                 (void) serialize_usec(f, "last-trigger-monotonic", t->last_trigger.monotonic);
 675
 676         return 0;
 677 }
 678
 679 static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 680         Timer *t = TIMER(u);
 681
 682         assert(u);
 683         assert(key);
 684         assert(value);
 685         assert(fds);
 686
 687         if (streq(key, "state")) {
 688                 TimerState state;
 689
 690                 state = timer_state_from_string(value);
 691                 if (state < 0)
 692                         log_unit_debug(u, "Failed to parse state value: %s", value);
 693                 else
 694                         t->deserialized_state = state;
 695
 696         } else if (streq(key, "result")) {
 697                 TimerResult f;
 698
 699                 f = timer_result_from_string(value);
 700                 if (f < 0)
 701                         log_unit_debug(u, "Failed to parse result value: %s", value);
 702                 else if (f != TIMER_SUCCESS)
 703                         t->result = f;
 704
 705         } else if (streq(key, "last-trigger-realtime"))
 706                 (void) deserialize_usec(value, &t->last_trigger.realtime);
 707         else if (streq(key, "last-trigger-monotonic"))
 708                 (void) deserialize_usec(value, &t->last_trigger.monotonic);
 709         else
 710                 log_unit_debug(u, "Unknown serialization key: %s", key);
 711
 712         return 0;
 713 }
 714
 715 _pure_ static UnitActiveState timer_active_state(Unit *u) {
 716         assert(u);
 717
 718         return state_translation_table[TIMER(u)->state];
 719 }
 720
 721 _pure_ static const char *timer_sub_state_to_string(Unit *u) {
 722         assert(u);
 723
 724         return timer_state_to_string(TIMER(u)->state);
 725 }
 726
 727 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata) {
 728         Timer *t = TIMER(userdata);
 729
 730         assert(t);
 731
 732         if (t->state != TIMER_WAITING)
 733                 return 0;
 734
 735         log_unit_debug(UNIT(t), "Timer elapsed.");
 736         timer_enter_running(t);
 737         return 0;
 738 }
 739
 740 static void timer_trigger_notify(Unit *u, Unit *other) {
 741         Timer *t = TIMER(u);
 742         TimerValue *v;
 743
 744         assert(u);
 745         assert(other);
 746
 747         if (other->load_state != UNIT_LOADED)
 748                 return;
 749
 750         /* Reenable all timers that depend on unit state */
 751         LIST_FOREACH(value, v, t->values)
 752                 if (IN_SET(v->base, TIMER_UNIT_ACTIVE, TIMER_UNIT_INACTIVE))
 753                         v->disabled = false;
 754
 755         switch (t->state) {
 756
 757         case TIMER_WAITING:
 758         case TIMER_ELAPSED:
 759
 760                 /* Recalculate sleep time */
 761                 timer_enter_waiting(t, false);
 762                 break;
 763
 764         case TIMER_RUNNING:
 765
 766                 if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
 767                         log_unit_debug(UNIT(t), "Got notified about unit deactivation.");
 768                         timer_enter_waiting(t, false);
 769                 }
 770                 break;
 771
 772         case TIMER_DEAD:
 773         case TIMER_FAILED:
 774                 break;
 775
 776         default:
 777                 assert_not_reached("Unknown timer state");
 778         }
 779 }
 780
 781 static void timer_reset_failed(Unit *u) {
 782         Timer *t = TIMER(u);
 783
 784         assert(t);
 785
 786         if (t->state == TIMER_FAILED)
 787                 timer_set_state(t, TIMER_DEAD);
 788
 789         t->result = TIMER_SUCCESS;
 790 }
 791
 792 static void timer_time_change(Unit *u) {
 793         Timer *t = TIMER(u);
 794         usec_t ts;
 795
 796         assert(u);
 797
 798         if (t->state != TIMER_WAITING)
 799                 return;
 800
 801         /* If we appear to have triggered in the future, the system clock must
 802          * have been set backwards.  So let's rewind our own clock and allow
 803          * the future trigger(s) to happen again :).  Exactly the same as when
 804          * you start a timer unit with Persistent=yes. */
 805         ts = now(CLOCK_REALTIME);
 806         if (t->last_trigger.realtime > ts)
 807                 t->last_trigger.realtime = ts;
 808
 809         if (t->on_clock_change) {
 810                 log_unit_debug(u, "Time change, triggering activation.");
 811                 timer_enter_running(t);
 812         } else {
 813                 log_unit_debug(u, "Time change, recalculating next elapse.");
 814                 timer_enter_waiting(t, true);
 815         }
 816 }
 817
 818 static void timer_timezone_change(Unit *u) {
 819         Timer *t = TIMER(u);
 820
 821         assert(u);
 822
 823         if (t->state != TIMER_WAITING)
 824                 return;
 825
 826         if (t->on_timezone_change) {
 827                 log_unit_debug(u, "Timezone change, triggering activation.");
 828                 timer_enter_running(t);
 829         } else {
 830                 log_unit_debug(u, "Timezone change, recalculating next elapse.");
 831                 timer_enter_waiting(t, false);
 832         }
 833 }
 834
 835 static int timer_clean(Unit *u, ExecCleanMask mask) {
 836         Timer *t = TIMER(u);
 837         int r;
 838
 839         assert(t);
 840         assert(mask != 0);
 841
 842         if (t->state != TIMER_DEAD)
 843                 return -EBUSY;
 844
 845         if (!IN_SET(mask, EXEC_CLEAN_STATE))
 846                 return -EUNATCH;
 847
 848         r = timer_setup_persistent(t);
 849         if (r < 0)
 850                 return r;
 851
 852         if (!t->stamp_path)
 853                 return -EUNATCH;
 854
 855         if (unlink(t->stamp_path) && errno != ENOENT)
 856                 return log_unit_error_errno(u, errno, "Failed to clean stamp file of timer: %m");
 857
 858         return 0;
 859 }
 860
 861 static int timer_can_clean(Unit *u, ExecCleanMask *ret) {
 862         Timer *t = TIMER(u);
 863
 864         assert(t);
 865
 866         *ret = t->persistent ? EXEC_CLEAN_STATE : 0;
 867         return 0;
 868 }
 869
 870 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
 871         [TIMER_ACTIVE] = "OnActiveSec",
 872         [TIMER_BOOT] = "OnBootSec",
 873         [TIMER_STARTUP] = "OnStartupSec",
 874         [TIMER_UNIT_ACTIVE] = "OnUnitActiveSec",
 875         [TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec",
 876         [TIMER_CALENDAR] = "OnCalendar"
 877 };
 878
 879 DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
 880
 881 static const char* const timer_result_table[_TIMER_RESULT_MAX] = {
 882         [TIMER_SUCCESS] = "success",
 883         [TIMER_FAILURE_RESOURCES] = "resources",
 884         [TIMER_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
 885 };
 886
 887 DEFINE_STRING_TABLE_LOOKUP(timer_result, TimerResult);
 888
 889 const UnitVTable timer_vtable = {
 890         .object_size = sizeof(Timer),
 891
 892         .sections =
 893                 "Unit\0"
 894                 "Timer\0"
 895                 "Install\0",
 896         .private_section = "Timer",
 897
 898         .can_transient = true,
 899         .can_fail = true,
 900         .can_trigger = true,
 901
 902         .init = timer_init,
 903         .done = timer_done,
 904         .load = timer_load,
 905
 906         .coldplug = timer_coldplug,
 907
 908         .dump = timer_dump,
 909
 910         .start = timer_start,
 911         .stop = timer_stop,
 912
 913         .clean = timer_clean,
 914         .can_clean = timer_can_clean,
 915
 916         .serialize = timer_serialize,
 917         .deserialize_item = timer_deserialize_item,
 918
 919         .active_state = timer_active_state,
 920         .sub_state_to_string = timer_sub_state_to_string,
 921
 922         .trigger_notify = timer_trigger_notify,
 923
 924         .reset_failed = timer_reset_failed,
 925         .time_change = timer_time_change,
 926         .timezone_change = timer_timezone_change,
 927
 928         .bus_vtable = bus_timer_vtable,
 929         .bus_set_property = bus_timer_set_property,
 930 };