src/core/timer.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   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_disable_unref(t->monotonic_event_source);
  69         t->realtime_event_source = sd_event_source_disable_unref(t->realtime_event_source);
  70
  71         t->stamp_path = mfree(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                 return log_unit_error_errno(UNIT(t), SYNTHETIC_ERRNO(ENOEXEC), "Timer unit lacks value setting. Refusing.");
  80
  81         return 0;
  82 }
  83
  84 static int timer_add_default_dependencies(Timer *t) {
  85         int r;
  86
  87         assert(t);
  88
  89         if (!UNIT(t)->default_dependencies)
  90                 return 0;
  91
  92         r = unit_add_dependency_by_name(UNIT(t), UNIT_BEFORE, SPECIAL_TIMERS_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  93         if (r < 0)
  94                 return r;
  95
  96         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
  97                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
  98                 if (r < 0)
  99                         return r;
 100
 101                 LIST_FOREACH(value, v, t->values) {
 102                         if (v->base != TIMER_CALENDAR)
 103                                 continue;
 104
 105                         FOREACH_STRING(target, SPECIAL_TIME_SYNC_TARGET, SPECIAL_TIME_SET_TARGET) {
 106                                 r = unit_add_dependency_by_name(UNIT(t), UNIT_AFTER, target, true, UNIT_DEPENDENCY_DEFAULT);
 107                                 if (r < 0)
 108                                         return r;
 109                         }
 110
 111                         break;
 112                 }
 113         }
 114
 115         return unit_add_two_dependencies_by_name(UNIT(t), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, true, UNIT_DEPENDENCY_DEFAULT);
 116 }
 117
 118 static int timer_add_trigger_dependencies(Timer *t) {
 119         Unit *x;
 120         int r;
 121
 122         assert(t);
 123
 124         if (UNIT_TRIGGER(UNIT(t)))
 125                 return 0;
 126
 127         r = unit_load_related_unit(UNIT(t), ".service", &x);
 128         if (r < 0)
 129                 return r;
 130
 131         return unit_add_two_dependencies(UNIT(t), UNIT_BEFORE, UNIT_TRIGGERS, x, true, UNIT_DEPENDENCY_IMPLICIT);
 132 }
 133
 134 static int timer_setup_persistent(Timer *t) {
 135         _cleanup_free_ char *stamp_path = NULL;
 136         int r;
 137
 138         assert(t);
 139
 140         if (!t->persistent)
 141                 return 0;
 142
 143         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
 144
 145                 r = unit_require_mounts_for(UNIT(t), "/var/lib/systemd/timers", UNIT_DEPENDENCY_FILE);
 146                 if (r < 0)
 147                         return r;
 148
 149                 stamp_path = strjoin("/var/lib/systemd/timers/stamp-", UNIT(t)->id);
 150         } else {
 151                 const char *e;
 152
 153                 e = getenv("XDG_DATA_HOME");
 154                 if (e)
 155                         stamp_path = strjoin(e, "/systemd/timers/stamp-", UNIT(t)->id);
 156                 else {
 157
 158                         _cleanup_free_ char *h = NULL;
 159
 160                         r = get_home_dir(&h);
 161                         if (r < 0)
 162                                 return log_unit_error_errno(UNIT(t), r, "Failed to determine home directory: %m");
 163
 164                         stamp_path = strjoin(h, "/.local/share/systemd/timers/stamp-", UNIT(t)->id);
 165                 }
 166         }
 167
 168         if (!stamp_path)
 169                 return log_oom();
 170
 171         return free_and_replace(t->stamp_path, stamp_path);
 172 }
 173
 174 static uint64_t timer_get_fixed_delay_hash(Timer *t) {
 175         static const uint8_t hash_key[] = {
 176                 0x51, 0x0a, 0xdb, 0x76, 0x29, 0x51, 0x42, 0xc2,
 177                 0x80, 0x35, 0xea, 0xe6, 0x8e, 0x3a, 0x37, 0xbd
 178         };
 179
 180         struct siphash state;
 181         sd_id128_t machine_id;
 182         uid_t uid;
 183         int r;
 184
 185         assert(t);
 186
 187         uid = getuid();
 188         r = sd_id128_get_machine(&machine_id);
 189         if (r < 0) {
 190                 log_unit_debug_errno(UNIT(t), r,
 191                                      "Failed to get machine ID for the fixed delay calculation, proceeding with 0: %m");
 192                 machine_id = SD_ID128_NULL;
 193         }
 194
 195         siphash24_init(&state, hash_key);
 196         siphash24_compress(&machine_id, sizeof(sd_id128_t), &state);
 197         siphash24_compress_boolean(MANAGER_IS_SYSTEM(UNIT(t)->manager), &state);
 198         siphash24_compress(&uid, sizeof(uid_t), &state);
 199         siphash24_compress_string(UNIT(t)->id, &state);
 200
 201         return siphash24_finalize(&state);
 202 }
 203
 204 static int timer_load(Unit *u) {
 205         Timer *t = TIMER(u);
 206         int r;
 207
 208         assert(u);
 209         assert(u->load_state == UNIT_STUB);
 210
 211         r = unit_load_fragment_and_dropin(u, true);
 212         if (r < 0)
 213                 return r;
 214
 215         if (u->load_state != UNIT_LOADED)
 216                 return 0;
 217
 218         /* This is a new unit? Then let's add in some extras */
 219         r = timer_add_trigger_dependencies(t);
 220         if (r < 0)
 221                 return r;
 222
 223         r = timer_setup_persistent(t);
 224         if (r < 0)
 225                 return r;
 226
 227         r = timer_add_default_dependencies(t);
 228         if (r < 0)
 229                 return r;
 230
 231         return timer_verify(t);
 232 }
 233
 234 static void timer_dump(Unit *u, FILE *f, const char *prefix) {
 235         Timer *t = TIMER(u);
 236         Unit *trigger;
 237
 238         trigger = UNIT_TRIGGER(u);
 239
 240         fprintf(f,
 241                 "%sTimer State: %s\n"
 242                 "%sResult: %s\n"
 243                 "%sUnit: %s\n"
 244                 "%sPersistent: %s\n"
 245                 "%sWakeSystem: %s\n"
 246                 "%sAccuracy: %s\n"
 247                 "%sRemainAfterElapse: %s\n"
 248                 "%sFixedRandomDelay: %s\n"
 249                 "%sOnClockChange: %s\n"
 250                 "%sOnTimeZoneChange: %s\n",
 251                 prefix, timer_state_to_string(t->state),
 252                 prefix, timer_result_to_string(t->result),
 253                 prefix, trigger ? trigger->id : "n/a",
 254                 prefix, yes_no(t->persistent),
 255                 prefix, yes_no(t->wake_system),
 256                 prefix, FORMAT_TIMESPAN(t->accuracy_usec, 1),
 257                 prefix, yes_no(t->remain_after_elapse),
 258                 prefix, yes_no(t->fixed_random_delay),
 259                 prefix, yes_no(t->on_clock_change),
 260                 prefix, yes_no(t->on_timezone_change));
 261
 262         LIST_FOREACH(value, v, t->values)
 263                 if (v->base == TIMER_CALENDAR) {
 264                         _cleanup_free_ char *p = NULL;
 265
 266                         (void) calendar_spec_to_string(v->calendar_spec, &p);
 267
 268                         fprintf(f,
 269                                 "%s%s: %s\n",
 270                                 prefix,
 271                                 timer_base_to_string(v->base),
 272                                 strna(p));
 273                 } else
 274                         fprintf(f,
 275                                 "%s%s: %s\n",
 276                                 prefix,
 277                                 timer_base_to_string(v->base),
 278                                 FORMAT_TIMESPAN(v->value, 0));
 279 }
 280
 281 static void timer_set_state(Timer *t, TimerState state) {
 282         TimerState old_state;
 283         assert(t);
 284
 285         if (t->state != state)
 286                 bus_unit_send_pending_change_signal(UNIT(t), false);
 287
 288         old_state = t->state;
 289         t->state = state;
 290
 291         if (state != TIMER_WAITING) {
 292                 t->monotonic_event_source = sd_event_source_disable_unref(t->monotonic_event_source);
 293                 t->realtime_event_source = sd_event_source_disable_unref(t->realtime_event_source);
 294                 t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
 295                 t->next_elapse_realtime = USEC_INFINITY;
 296         }
 297
 298         if (state != old_state)
 299                 log_unit_debug(UNIT(t), "Changed %s -> %s", timer_state_to_string(old_state), timer_state_to_string(state));
 300
 301         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], /* reload_success = */ true);
 302 }
 303
 304 static void timer_enter_waiting(Timer *t, bool time_change);
 305
 306 static int timer_coldplug(Unit *u) {
 307         Timer *t = TIMER(u);
 308
 309         assert(t);
 310         assert(t->state == TIMER_DEAD);
 311
 312         if (t->deserialized_state == t->state)
 313                 return 0;
 314
 315         if (t->deserialized_state == TIMER_WAITING)
 316                 timer_enter_waiting(t, false);
 317         else
 318                 timer_set_state(t, t->deserialized_state);
 319
 320         return 0;
 321 }
 322
 323 static void timer_enter_dead(Timer *t, TimerResult f) {
 324         assert(t);
 325
 326         if (t->result == TIMER_SUCCESS)
 327                 t->result = f;
 328
 329         unit_log_result(UNIT(t), t->result == TIMER_SUCCESS, timer_result_to_string(t->result));
 330         timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
 331 }
 332
 333 static void timer_enter_elapsed(Timer *t, bool leave_around) {
 334         assert(t);
 335
 336         /* If a unit is marked with RemainAfterElapse=yes we leave it
 337          * around even after it elapsed once, so that starting it
 338          * later again does not necessarily mean immediate
 339          * retriggering. We unconditionally leave units with
 340          * TIMER_UNIT_ACTIVE or TIMER_UNIT_INACTIVE triggers around,
 341          * since they might be restarted automatically at any time
 342          * later on. */
 343
 344         if (t->remain_after_elapse || leave_around)
 345                 timer_set_state(t, TIMER_ELAPSED);
 346         else
 347                 timer_enter_dead(t, TIMER_SUCCESS);
 348 }
 349
 350 static void add_random(Timer *t, usec_t *v) {
 351         usec_t add;
 352
 353         assert(t);
 354         assert(v);
 355
 356         if (t->random_usec == 0)
 357                 return;
 358         if (*v == USEC_INFINITY)
 359                 return;
 360
 361         add = (t->fixed_random_delay ? timer_get_fixed_delay_hash(t) : random_u64()) % t->random_usec;
 362
 363         if (*v + add < *v) /* overflow */
 364                 *v = (usec_t) -2; /* Highest possible value, that is not USEC_INFINITY */
 365         else
 366                 *v += add;
 367
 368         log_unit_debug(UNIT(t), "Adding %s random time.", FORMAT_TIMESPAN(add, 0));
 369 }
 370
 371 static void timer_enter_waiting(Timer *t, bool time_change) {
 372         bool found_monotonic = false, found_realtime = false;
 373         bool leave_around = false;
 374         triple_timestamp ts;
 375         Unit *trigger;
 376         int r;
 377
 378         assert(t);
 379
 380         trigger = UNIT_TRIGGER(UNIT(t));
 381         if (!trigger) {
 382                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 383                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 384                 return;
 385         }
 386
 387         triple_timestamp_get(&ts);
 388         t->next_elapse_monotonic_or_boottime = t->next_elapse_realtime = 0;
 389
 390         LIST_FOREACH(value, v, t->values) {
 391                 if (v->disabled)
 392                         continue;
 393
 394                 if (v->base == TIMER_CALENDAR) {
 395                         usec_t b, rebased;
 396
 397                         /* If we know the last time this was
 398                          * triggered, schedule the job based relative
 399                          * to that. If we don't, just start from
 400                          * the activation time. */
 401
 402                         if (dual_timestamp_is_set(&t->last_trigger))
 403                                 b = t->last_trigger.realtime;
 404                         else if (dual_timestamp_is_set(&UNIT(t)->inactive_exit_timestamp))
 405                                 b = UNIT(t)->inactive_exit_timestamp.realtime;
 406                         else
 407                                 b = ts.realtime;
 408
 409                         r = calendar_spec_next_usec(v->calendar_spec, b, &v->next_elapse);
 410                         if (r < 0)
 411                                 continue;
 412
 413                         /* To make the delay due to RandomizedDelaySec= work even at boot, if the scheduled
 414                          * time has already passed, set the time when systemd first started as the scheduled
 415                          * time. Note that we base this on the monotonic timestamp of the boot, not the
 416                          * realtime one, since the wallclock might have been off during boot. */
 417                         rebased = map_clock_usec(UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].monotonic,
 418                                                  CLOCK_MONOTONIC, CLOCK_REALTIME);
 419                         if (v->next_elapse < rebased)
 420                                 v->next_elapse = rebased;
 421
 422                         if (!found_realtime)
 423                                 t->next_elapse_realtime = v->next_elapse;
 424                         else
 425                                 t->next_elapse_realtime = MIN(t->next_elapse_realtime, v->next_elapse);
 426
 427                         found_realtime = true;
 428
 429                 } else {
 430                         usec_t base;
 431
 432                         switch (v->base) {
 433
 434                         case TIMER_ACTIVE:
 435                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 436                                         base = UNIT(t)->inactive_exit_timestamp.monotonic;
 437                                 else
 438                                         base = ts.monotonic;
 439                                 break;
 440
 441                         case TIMER_BOOT:
 442                                 if (detect_container() <= 0) {
 443                                         /* CLOCK_MONOTONIC equals the uptime on Linux */
 444                                         base = 0;
 445                                         break;
 446                                 }
 447                                 /* In a container we don't want to include the time the host
 448                                  * was already up when the container started, so count from
 449                                  * our own startup. */
 450                                 _fallthrough_;
 451                         case TIMER_STARTUP:
 452                                 base = UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].monotonic;
 453                                 break;
 454
 455                         case TIMER_UNIT_ACTIVE:
 456                                 leave_around = true;
 457                                 base = MAX(trigger->inactive_exit_timestamp.monotonic, t->last_trigger.monotonic);
 458                                 if (base <= 0)
 459                                         continue;
 460                                 break;
 461
 462                         case TIMER_UNIT_INACTIVE:
 463                                 leave_around = true;
 464                                 base = MAX(trigger->inactive_enter_timestamp.monotonic, t->last_trigger.monotonic);
 465                                 if (base <= 0)
 466                                         continue;
 467                                 break;
 468
 469                         default:
 470                                 assert_not_reached();
 471                         }
 472
 473                         v->next_elapse = usec_add(usec_shift_clock(base, CLOCK_MONOTONIC, TIMER_MONOTONIC_CLOCK(t)), v->value);
 474
 475                         if (dual_timestamp_is_set(&t->last_trigger) &&
 476                             !time_change &&
 477                             v->next_elapse < triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)) &&
 478                             IN_SET(v->base, TIMER_ACTIVE, TIMER_BOOT, TIMER_STARTUP)) {
 479                                 /* This is a one time trigger, disable it now */
 480                                 v->disabled = true;
 481                                 continue;
 482                         }
 483
 484                         if (!found_monotonic)
 485                                 t->next_elapse_monotonic_or_boottime = v->next_elapse;
 486                         else
 487                                 t->next_elapse_monotonic_or_boottime = MIN(t->next_elapse_monotonic_or_boottime, v->next_elapse);
 488
 489                         found_monotonic = true;
 490                 }
 491         }
 492
 493         if (!found_monotonic && !found_realtime && !t->on_timezone_change && !t->on_clock_change) {
 494                 log_unit_debug(UNIT(t), "Timer is elapsed.");
 495                 timer_enter_elapsed(t, leave_around);
 496                 return;
 497         }
 498
 499         if (found_monotonic) {
 500                 usec_t left;
 501
 502                 add_random(t, &t->next_elapse_monotonic_or_boottime);
 503
 504                 left = usec_sub_unsigned(t->next_elapse_monotonic_or_boottime, triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)));
 505                 log_unit_debug(UNIT(t), "Monotonic timer elapses in %s.", FORMAT_TIMESPAN(left, 0));
 506
 507                 if (t->monotonic_event_source) {
 508                         r = sd_event_source_set_time(t->monotonic_event_source, t->next_elapse_monotonic_or_boottime);
 509                         if (r < 0)
 510                                 goto fail;
 511
 512                         r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_ONESHOT);
 513                         if (r < 0)
 514                                 goto fail;
 515                 } else {
 516
 517                         r = sd_event_add_time(
 518                                         UNIT(t)->manager->event,
 519                                         &t->monotonic_event_source,
 520                                         t->wake_system ? CLOCK_BOOTTIME_ALARM : CLOCK_MONOTONIC,
 521                                         t->next_elapse_monotonic_or_boottime, t->accuracy_usec,
 522                                         timer_dispatch, t);
 523                         if (r < 0)
 524                                 goto fail;
 525
 526                         (void) sd_event_source_set_description(t->monotonic_event_source, "timer-monotonic");
 527                 }
 528
 529         } else if (t->monotonic_event_source) {
 530
 531                 r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_OFF);
 532                 if (r < 0)
 533                         goto fail;
 534         }
 535
 536         if (found_realtime) {
 537                 add_random(t, &t->next_elapse_realtime);
 538
 539                 log_unit_debug(UNIT(t), "Realtime timer elapses at %s.", FORMAT_TIMESTAMP(t->next_elapse_realtime));
 540
 541                 if (t->realtime_event_source) {
 542                         r = sd_event_source_set_time(t->realtime_event_source, t->next_elapse_realtime);
 543                         if (r < 0)
 544                                 goto fail;
 545
 546                         r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_ONESHOT);
 547                         if (r < 0)
 548                                 goto fail;
 549                 } else {
 550                         r = sd_event_add_time(
 551                                         UNIT(t)->manager->event,
 552                                         &t->realtime_event_source,
 553                                         t->wake_system ? CLOCK_REALTIME_ALARM : CLOCK_REALTIME,
 554                                         t->next_elapse_realtime, t->accuracy_usec,
 555                                         timer_dispatch, t);
 556                         if (r < 0)
 557                                 goto fail;
 558
 559                         (void) sd_event_source_set_description(t->realtime_event_source, "timer-realtime");
 560                 }
 561
 562         } else if (t->realtime_event_source) {
 563
 564                 r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_OFF);
 565                 if (r < 0)
 566                         goto fail;
 567         }
 568
 569         timer_set_state(t, TIMER_WAITING);
 570         return;
 571
 572 fail:
 573         log_unit_warning_errno(UNIT(t), r, "Failed to enter waiting state: %m");
 574         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 575 }
 576
 577 static void timer_enter_running(Timer *t) {
 578         _cleanup_(activation_details_unrefp) ActivationDetails *details = NULL;
 579         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 580         Unit *trigger;
 581         Job *job;
 582         int r;
 583
 584         assert(t);
 585
 586         /* Don't start job if we are supposed to go down */
 587         if (unit_stop_pending(UNIT(t)))
 588                 return;
 589
 590         trigger = UNIT_TRIGGER(UNIT(t));
 591         if (!trigger) {
 592                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 593                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 594                 return;
 595         }
 596
 597         details = activation_details_new(UNIT(t));
 598         if (!details) {
 599                 r = -ENOMEM;
 600                 goto fail;
 601         }
 602
 603         r = manager_add_job(UNIT(t)->manager, JOB_START, trigger, JOB_REPLACE, NULL, &error, &job);
 604         if (r < 0)
 605                 goto fail;
 606
 607         dual_timestamp_get(&t->last_trigger);
 608         ACTIVATION_DETAILS_TIMER(details)->last_trigger = t->last_trigger;
 609
 610         job_set_activation_details(job, details);
 611
 612         if (t->stamp_path)
 613                 touch_file(t->stamp_path, true, t->last_trigger.realtime, UID_INVALID, GID_INVALID, MODE_INVALID);
 614
 615         timer_set_state(t, TIMER_RUNNING);
 616         return;
 617
 618 fail:
 619         log_unit_warning(UNIT(t), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
 620         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 621 }
 622
 623 static int timer_start(Unit *u) {
 624         Timer *t = TIMER(u);
 625         int r;
 626
 627         assert(t);
 628         assert(IN_SET(t->state, TIMER_DEAD, TIMER_FAILED));
 629
 630         r = unit_test_trigger_loaded(u);
 631         if (r < 0)
 632                 return r;
 633
 634         r = unit_acquire_invocation_id(u);
 635         if (r < 0)
 636                 return r;
 637
 638         t->last_trigger = DUAL_TIMESTAMP_NULL;
 639
 640         /* Reenable all timers that depend on unit activation time */
 641         LIST_FOREACH(value, v, t->values)
 642                 if (v->base == TIMER_ACTIVE)
 643                         v->disabled = false;
 644
 645         if (t->stamp_path) {
 646                 struct stat st;
 647
 648                 if (stat(t->stamp_path, &st) >= 0) {
 649                         usec_t ft;
 650
 651                         /* Load the file timestamp, but only if it is actually in the past. If it is in the future,
 652                          * something is wrong with the system clock. */
 653
 654                         ft = timespec_load(&st.st_mtim);
 655                         if (ft < now(CLOCK_REALTIME))
 656                                 t->last_trigger.realtime = ft;
 657                         else
 658                                 log_unit_warning(u, "Not using persistent file timestamp %s as it is in the future.",
 659                                                  FORMAT_TIMESTAMP(ft));
 660
 661                 } else if (errno == ENOENT)
 662                         /* The timer has never run before, make sure a stamp file exists. */
 663                         (void) touch_file(t->stamp_path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
 664         }
 665
 666         t->result = TIMER_SUCCESS;
 667         timer_enter_waiting(t, false);
 668         return 1;
 669 }
 670
 671 static int timer_stop(Unit *u) {
 672         Timer *t = TIMER(u);
 673
 674         assert(t);
 675         assert(IN_SET(t->state, TIMER_WAITING, TIMER_RUNNING, TIMER_ELAPSED));
 676
 677         timer_enter_dead(t, TIMER_SUCCESS);
 678         return 1;
 679 }
 680
 681 static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
 682         Timer *t = TIMER(u);
 683
 684         assert(u);
 685         assert(f);
 686         assert(fds);
 687
 688         (void) serialize_item(f, "state", timer_state_to_string(t->state));
 689         (void) serialize_item(f, "result", timer_result_to_string(t->result));
 690
 691         if (dual_timestamp_is_set(&t->last_trigger))
 692                 (void) serialize_usec(f, "last-trigger-realtime", t->last_trigger.realtime);
 693
 694         if (t->last_trigger.monotonic > 0)
 695                 (void) serialize_usec(f, "last-trigger-monotonic", t->last_trigger.monotonic);
 696
 697         return 0;
 698 }
 699
 700 static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 701         Timer *t = TIMER(u);
 702
 703         assert(u);
 704         assert(key);
 705         assert(value);
 706         assert(fds);
 707
 708         if (streq(key, "state")) {
 709                 TimerState state;
 710
 711                 state = timer_state_from_string(value);
 712                 if (state < 0)
 713                         log_unit_debug(u, "Failed to parse state value: %s", value);
 714                 else
 715                         t->deserialized_state = state;
 716
 717         } else if (streq(key, "result")) {
 718                 TimerResult f;
 719
 720                 f = timer_result_from_string(value);
 721                 if (f < 0)
 722                         log_unit_debug(u, "Failed to parse result value: %s", value);
 723                 else if (f != TIMER_SUCCESS)
 724                         t->result = f;
 725
 726         } else if (streq(key, "last-trigger-realtime"))
 727                 (void) deserialize_usec(value, &t->last_trigger.realtime);
 728         else if (streq(key, "last-trigger-monotonic"))
 729                 (void) deserialize_usec(value, &t->last_trigger.monotonic);
 730         else
 731                 log_unit_debug(u, "Unknown serialization key: %s", key);
 732
 733         return 0;
 734 }
 735
 736 _pure_ static UnitActiveState timer_active_state(Unit *u) {
 737         assert(u);
 738
 739         return state_translation_table[TIMER(u)->state];
 740 }
 741
 742 _pure_ static const char *timer_sub_state_to_string(Unit *u) {
 743         assert(u);
 744
 745         return timer_state_to_string(TIMER(u)->state);
 746 }
 747
 748 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata) {
 749         Timer *t = TIMER(userdata);
 750
 751         assert(t);
 752
 753         if (t->state != TIMER_WAITING)
 754                 return 0;
 755
 756         log_unit_debug(UNIT(t), "Timer elapsed.");
 757         timer_enter_running(t);
 758         return 0;
 759 }
 760
 761 static void timer_trigger_notify(Unit *u, Unit *other) {
 762         Timer *t = TIMER(u);
 763
 764         assert(u);
 765         assert(other);
 766
 767         /* Filter out invocations with bogus state */
 768         assert(UNIT_IS_LOAD_COMPLETE(other->load_state));
 769
 770         /* Reenable all timers that depend on unit state */
 771         LIST_FOREACH(value, v, t->values)
 772                 if (IN_SET(v->base, TIMER_UNIT_ACTIVE, TIMER_UNIT_INACTIVE))
 773                         v->disabled = false;
 774
 775         switch (t->state) {
 776
 777         case TIMER_WAITING:
 778         case TIMER_ELAPSED:
 779
 780                 /* Recalculate sleep time */
 781                 timer_enter_waiting(t, false);
 782                 break;
 783
 784         case TIMER_RUNNING:
 785
 786                 if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
 787                         log_unit_debug(UNIT(t), "Got notified about unit deactivation.");
 788                         timer_enter_waiting(t, false);
 789                 }
 790                 break;
 791
 792         case TIMER_DEAD:
 793         case TIMER_FAILED:
 794                 break;
 795
 796         default:
 797                 assert_not_reached();
 798         }
 799 }
 800
 801 static void timer_reset_failed(Unit *u) {
 802         Timer *t = TIMER(u);
 803
 804         assert(t);
 805
 806         if (t->state == TIMER_FAILED)
 807                 timer_set_state(t, TIMER_DEAD);
 808
 809         t->result = TIMER_SUCCESS;
 810 }
 811
 812 static void timer_time_change(Unit *u) {
 813         Timer *t = TIMER(u);
 814         usec_t ts;
 815
 816         assert(u);
 817
 818         if (t->state != TIMER_WAITING)
 819                 return;
 820
 821         /* If we appear to have triggered in the future, the system clock must
 822          * have been set backwards.  So let's rewind our own clock and allow
 823          * the future triggers to happen again :).  Exactly the same as when
 824          * you start a timer unit with Persistent=yes. */
 825         ts = now(CLOCK_REALTIME);
 826         if (t->last_trigger.realtime > ts)
 827                 t->last_trigger.realtime = ts;
 828
 829         if (t->on_clock_change) {
 830                 log_unit_debug(u, "Time change, triggering activation.");
 831                 timer_enter_running(t);
 832         } else {
 833                 log_unit_debug(u, "Time change, recalculating next elapse.");
 834                 timer_enter_waiting(t, true);
 835         }
 836 }
 837
 838 static void timer_timezone_change(Unit *u) {
 839         Timer *t = TIMER(u);
 840
 841         assert(u);
 842
 843         if (t->state != TIMER_WAITING)
 844                 return;
 845
 846         if (t->on_timezone_change) {
 847                 log_unit_debug(u, "Timezone change, triggering activation.");
 848                 timer_enter_running(t);
 849         } else {
 850                 log_unit_debug(u, "Timezone change, recalculating next elapse.");
 851                 timer_enter_waiting(t, false);
 852         }
 853 }
 854
 855 static int timer_clean(Unit *u, ExecCleanMask mask) {
 856         Timer *t = TIMER(u);
 857         int r;
 858
 859         assert(t);
 860         assert(mask != 0);
 861
 862         if (t->state != TIMER_DEAD)
 863                 return -EBUSY;
 864
 865         if (mask != EXEC_CLEAN_STATE)
 866                 return -EUNATCH;
 867
 868         r = timer_setup_persistent(t);
 869         if (r < 0)
 870                 return r;
 871
 872         if (!t->stamp_path)
 873                 return -EUNATCH;
 874
 875         if (unlink(t->stamp_path) && errno != ENOENT)
 876                 return log_unit_error_errno(u, errno, "Failed to clean stamp file of timer: %m");
 877
 878         return 0;
 879 }
 880
 881 static int timer_can_clean(Unit *u, ExecCleanMask *ret) {
 882         Timer *t = TIMER(u);
 883
 884         assert(t);
 885         assert(ret);
 886
 887         *ret = t->persistent ? EXEC_CLEAN_STATE : 0;
 888         return 0;
 889 }
 890
 891 static int timer_can_start(Unit *u) {
 892         Timer *t = TIMER(u);
 893         int r;
 894
 895         assert(t);
 896
 897         r = unit_test_start_limit(u);
 898         if (r < 0) {
 899                 timer_enter_dead(t, TIMER_FAILURE_START_LIMIT_HIT);
 900                 return r;
 901         }
 902
 903         return 1;
 904 }
 905
 906 static void activation_details_timer_serialize(ActivationDetails *details, FILE *f) {
 907         ActivationDetailsTimer *t = ACTIVATION_DETAILS_TIMER(details);
 908
 909         assert(details);
 910         assert(f);
 911         assert(t);
 912
 913         (void) serialize_dual_timestamp(f, "activation-details-timer-last-trigger", &t->last_trigger);
 914 }
 915
 916 static int activation_details_timer_deserialize(const char *key, const char *value, ActivationDetails **details) {
 917         int r;
 918
 919         assert(key);
 920         assert(value);
 921
 922         if (!details || !*details)
 923                 return -EINVAL;
 924
 925         ActivationDetailsTimer *t = ACTIVATION_DETAILS_TIMER(*details);
 926         if (!t)
 927                 return -EINVAL;
 928
 929         if (!streq(key, "activation-details-timer-last-trigger"))
 930                 return -EINVAL;
 931
 932         r = deserialize_dual_timestamp(value, &t->last_trigger);
 933         if (r < 0)
 934                 return r;
 935
 936         return 0;
 937 }
 938
 939 static int activation_details_timer_append_env(ActivationDetails *details, char ***strv) {
 940         ActivationDetailsTimer *t = ACTIVATION_DETAILS_TIMER(details);
 941         int r;
 942
 943         assert(details);
 944         assert(strv);
 945         assert(t);
 946
 947         if (!dual_timestamp_is_set(&t->last_trigger))
 948                 return 0;
 949
 950         r = strv_extendf(strv, "TRIGGER_TIMER_REALTIME_USEC=" USEC_FMT, t->last_trigger.realtime);
 951         if (r < 0)
 952                 return r;
 953
 954         r = strv_extendf(strv, "TRIGGER_TIMER_MONOTONIC_USEC=" USEC_FMT, t->last_trigger.monotonic);
 955         if (r < 0)
 956                 return r;
 957
 958         return 2; /* Return the number of variables added to the env block */
 959 }
 960
 961 static int activation_details_timer_append_pair(ActivationDetails *details, char ***strv) {
 962         ActivationDetailsTimer *t = ACTIVATION_DETAILS_TIMER(details);
 963         int r;
 964
 965         assert(details);
 966         assert(strv);
 967         assert(t);
 968
 969         if (!dual_timestamp_is_set(&t->last_trigger))
 970                 return 0;
 971
 972         r = strv_extend(strv, "trigger_timer_realtime_usec");
 973         if (r < 0)
 974                 return r;
 975
 976         r = strv_extendf(strv, USEC_FMT, t->last_trigger.realtime);
 977         if (r < 0)
 978                 return r;
 979
 980         r = strv_extend(strv, "trigger_timer_monotonic_usec");
 981         if (r < 0)
 982                 return r;
 983
 984         r = strv_extendf(strv, USEC_FMT, t->last_trigger.monotonic);
 985         if (r < 0)
 986                 return r;
 987
 988         return 2; /* Return the number of pairs added to the env block */
 989 }
 990
 991 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
 992         [TIMER_ACTIVE]        = "OnActiveSec",
 993         [TIMER_BOOT]          = "OnBootSec",
 994         [TIMER_STARTUP]       = "OnStartupSec",
 995         [TIMER_UNIT_ACTIVE]   = "OnUnitActiveSec",
 996         [TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec",
 997         [TIMER_CALENDAR]      = "OnCalendar"
 998 };
 999
1000 DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
1001
1002 static const char* const timer_result_table[_TIMER_RESULT_MAX] = {
1003         [TIMER_SUCCESS]                 = "success",
1004         [TIMER_FAILURE_RESOURCES]       = "resources",
1005         [TIMER_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
1006 };
1007
1008 DEFINE_STRING_TABLE_LOOKUP(timer_result, TimerResult);
1009
1010 const UnitVTable timer_vtable = {
1011         .object_size = sizeof(Timer),
1012
1013         .sections =
1014                 "Unit\0"
1015                 "Timer\0"
1016                 "Install\0",
1017         .private_section = "Timer",
1018
1019         .can_transient = true,
1020         .can_fail = true,
1021         .can_trigger = true,
1022
1023         .init = timer_init,
1024         .done = timer_done,
1025         .load = timer_load,
1026
1027         .coldplug = timer_coldplug,
1028
1029         .dump = timer_dump,
1030
1031         .start = timer_start,
1032         .stop = timer_stop,
1033
1034         .clean = timer_clean,
1035         .can_clean = timer_can_clean,
1036
1037         .serialize = timer_serialize,
1038         .deserialize_item = timer_deserialize_item,
1039
1040         .active_state = timer_active_state,
1041         .sub_state_to_string = timer_sub_state_to_string,
1042
1043         .trigger_notify = timer_trigger_notify,
1044
1045         .reset_failed = timer_reset_failed,
1046         .time_change = timer_time_change,
1047         .timezone_change = timer_timezone_change,
1048
1049         .bus_set_property = bus_timer_set_property,
1050
1051         .can_start = timer_can_start,
1052 };
1053
1054 const ActivationDetailsVTable activation_details_timer_vtable = {
1055         .object_size = sizeof(ActivationDetailsTimer),
1056
1057         .serialize = activation_details_timer_serialize,
1058         .deserialize = activation_details_timer_deserialize,
1059         .append_env = activation_details_timer_append_env,
1060         .append_pair = activation_details_timer_append_pair,
1061 };