src/core/timer.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9
  10 #include "alloc-util.h"
  11 #include "bus-error.h"
  12 #include "bus-util.h"
  13 #include "dbus-timer.h"
  14 #include "fs-util.h"
  15 #include "parse-util.h"
  16 #include "random-util.h"
  17 #include "special.h"
  18 #include "string-table.h"
  19 #include "string-util.h"
  20 #include "timer.h"
  21 #include "unit-name.h"
  22 #include "unit.h"
  23 #include "user-util.h"
  24 #include "virt.h"
  25
  26 static const UnitActiveState state_translation_table[_TIMER_STATE_MAX] = {
  27         [TIMER_DEAD] = UNIT_INACTIVE,
  28         [TIMER_WAITING] = UNIT_ACTIVE,
  29         [TIMER_RUNNING] = UNIT_ACTIVE,
  30         [TIMER_ELAPSED] = UNIT_ACTIVE,
  31         [TIMER_FAILED] = UNIT_FAILED
  32 };
  33
  34 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata);
  35
  36 static void timer_init(Unit *u) {
  37         Timer *t = TIMER(u);
  38
  39         assert(u);
  40         assert(u->load_state == UNIT_STUB);
  41
  42         t->next_elapse_monotonic_or_boottime = USEC_INFINITY;
  43         t->next_elapse_realtime = USEC_INFINITY;
  44         t->accuracy_usec = u->manager->default_timer_accuracy_usec;
  45         t->remain_after_elapse = true;
  46 }
  47
  48 void timer_free_values(Timer *t) {
  49         TimerValue *v;
  50
  51         assert(t);
  52
  53         while ((v = t->values)) {
  54                 LIST_REMOVE(value, t->values, v);
  55                 calendar_spec_free(v->calendar_spec);
  56                 free(v);
  57         }
  58 }
  59
  60 static void timer_done(Unit *u) {
  61         Timer *t = TIMER(u);
  62
  63         assert(t);
  64
  65         timer_free_values(t);
  66
  67         t->monotonic_event_source = sd_event_source_unref(t->monotonic_event_source);
  68         t->realtime_event_source = sd_event_source_unref(t->realtime_event_source);
  69
  70         free(t->stamp_path);
  71 }
  72
  73 static int timer_verify(Timer *t) {
  74         assert(t);
  75
  76         if (UNIT(t)->load_state != UNIT_LOADED)
  77                 return 0;
  78
  79         if (!t->values) {
  80                 log_unit_error(UNIT(t), "Timer unit lacks value setting. Refusing.");
  81                 return -EINVAL;
  82         }
  83
  84         return 0;
  85 }
  86
  87 static int timer_add_default_dependencies(Timer *t) {
  88         int r;
  89         TimerValue *v;
  90
  91         assert(t);
  92
  93         if (!UNIT(t)->default_dependencies)
  94                 return 0;
  95
  96         r = unit_add_dependency_by_name(UNIT(t), UNIT_BEFORE, SPECIAL_TIMERS_TARGET, NULL, true, UNIT_DEPENDENCY_DEFAULT);
  97         if (r < 0)
  98                 return r;
  99
 100         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
 101                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true, UNIT_DEPENDENCY_DEFAULT);
 102                 if (r < 0)
 103                         return r;
 104
 105                 LIST_FOREACH(value, v, t->values) {
 106                         if (v->base == TIMER_CALENDAR) {
 107                                 r = unit_add_dependency_by_name(UNIT(t), UNIT_AFTER, SPECIAL_TIME_SYNC_TARGET, NULL, true, UNIT_DEPENDENCY_DEFAULT);
 108                                 if (r < 0)
 109                                         return r;
 110                                 break;
 111                         }
 112                 }
 113         }
 114
 115         return unit_add_two_dependencies_by_name(UNIT(t), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, 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 (!hashmap_isempty(UNIT(t)->dependencies[UNIT_TRIGGERS]))
 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         int r;
 136
 137         assert(t);
 138
 139         if (!t->persistent)
 140                 return 0;
 141
 142         if (MANAGER_IS_SYSTEM(UNIT(t)->manager)) {
 143
 144                 r = unit_require_mounts_for(UNIT(t), "/var/lib/systemd/timers", UNIT_DEPENDENCY_FILE);
 145                 if (r < 0)
 146                         return r;
 147
 148                 t->stamp_path = strappend("/var/lib/systemd/timers/stamp-", UNIT(t)->id);
 149         } else {
 150                 const char *e;
 151
 152                 e = getenv("XDG_DATA_HOME");
 153                 if (e)
 154                         t->stamp_path = strjoin(e, "/systemd/timers/stamp-", UNIT(t)->id);
 155                 else {
 156
 157                         _cleanup_free_ char *h = NULL;
 158
 159                         r = get_home_dir(&h);
 160                         if (r < 0)
 161                                 return log_unit_error_errno(UNIT(t), r, "Failed to determine home directory: %m");
 162
 163                         t->stamp_path = strjoin(h, "/.local/share/systemd/timers/stamp-", UNIT(t)->id);
 164                 }
 165         }
 166
 167         if (!t->stamp_path)
 168                 return log_oom();
 169
 170         return 0;
 171 }
 172
 173 static int timer_load(Unit *u) {
 174         Timer *t = TIMER(u);
 175         int r;
 176
 177         assert(u);
 178         assert(u->load_state == UNIT_STUB);
 179
 180         r = unit_load_fragment_and_dropin(u);
 181         if (r < 0)
 182                 return r;
 183
 184         if (u->load_state == UNIT_LOADED) {
 185
 186                 r = timer_add_trigger_dependencies(t);
 187                 if (r < 0)
 188                         return r;
 189
 190                 r = timer_setup_persistent(t);
 191                 if (r < 0)
 192                         return r;
 193
 194                 r = timer_add_default_dependencies(t);
 195                 if (r < 0)
 196                         return r;
 197         }
 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                 prefix, timer_state_to_string(t->state),
 219                 prefix, timer_result_to_string(t->result),
 220                 prefix, trigger ? trigger->id : "n/a",
 221                 prefix, yes_no(t->persistent),
 222                 prefix, yes_no(t->wake_system),
 223                 prefix, format_timespan(buf, sizeof(buf), t->accuracy_usec, 1),
 224                 prefix, yes_no(t->remain_after_elapse));
 225
 226         LIST_FOREACH(value, v, t->values) {
 227
 228                 if (v->base == TIMER_CALENDAR) {
 229                         _cleanup_free_ char *p = NULL;
 230
 231                         (void) calendar_spec_to_string(v->calendar_spec, &p);
 232
 233                         fprintf(f,
 234                                 "%s%s: %s\n",
 235                                 prefix,
 236                                 timer_base_to_string(v->base),
 237                                 strna(p));
 238                 } else  {
 239                         char timespan1[FORMAT_TIMESPAN_MAX];
 240
 241                         fprintf(f,
 242                                 "%s%s: %s\n",
 243                                 prefix,
 244                                 timer_base_to_string(v->base),
 245                                 format_timespan(timespan1, sizeof(timespan1), v->value, 0));
 246                 }
 247         }
 248 }
 249
 250 static void timer_set_state(Timer *t, TimerState state) {
 251         TimerState old_state;
 252         assert(t);
 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 initial);
 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         if (t->result != TIMER_SUCCESS)
 296                 log_unit_warning(UNIT(t), "Failed with result '%s'.", timer_result_to_string(t->result));
 297
 298         timer_set_state(t, t->result != TIMER_SUCCESS ? TIMER_FAILED : TIMER_DEAD);
 299 }
 300
 301 static void timer_enter_elapsed(Timer *t, bool leave_around) {
 302         assert(t);
 303
 304         /* If a unit is marked with RemainAfterElapse=yes we leave it
 305          * around even after it elapsed once, so that starting it
 306          * later again does not necessarily mean immediate
 307          * retriggering. We unconditionally leave units with
 308          * TIMER_UNIT_ACTIVE or TIMER_UNIT_INACTIVE triggers around,
 309          * since they might be restarted automatically at any time
 310          * later on. */
 311
 312         if (t->remain_after_elapse || leave_around)
 313                 timer_set_state(t, TIMER_ELAPSED);
 314         else
 315                 timer_enter_dead(t, TIMER_SUCCESS);
 316 }
 317
 318 static void add_random(Timer *t, usec_t *v) {
 319         char s[FORMAT_TIMESPAN_MAX];
 320         usec_t add;
 321
 322         assert(t);
 323         assert(v);
 324
 325         if (t->random_usec == 0)
 326                 return;
 327         if (*v == USEC_INFINITY)
 328                 return;
 329
 330         add = random_u64() % t->random_usec;
 331
 332         if (*v + add < *v) /* overflow */
 333                 *v = (usec_t) -2; /* Highest possible value, that is not USEC_INFINITY */
 334         else
 335                 *v += add;
 336
 337         log_unit_debug(UNIT(t), "Adding %s random time.", format_timespan(s, sizeof(s), add, 0));
 338 }
 339
 340 static void timer_enter_waiting(Timer *t, bool initial) {
 341         bool found_monotonic = false, found_realtime = false;
 342         bool leave_around = false;
 343         triple_timestamp ts;
 344         TimerValue *v;
 345         Unit *trigger;
 346         int r;
 347
 348         assert(t);
 349
 350         trigger = UNIT_TRIGGER(UNIT(t));
 351         if (!trigger) {
 352                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 353                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 354                 return;
 355         }
 356
 357         triple_timestamp_get(&ts);
 358         t->next_elapse_monotonic_or_boottime = t->next_elapse_realtime = 0;
 359
 360         LIST_FOREACH(value, v, t->values) {
 361                 if (v->disabled)
 362                         continue;
 363
 364                 if (v->base == TIMER_CALENDAR) {
 365                         usec_t b;
 366
 367                         /* If we know the last time this was
 368                          * triggered, schedule the job based relative
 369                          * to that. If we don't, just start from
 370                          * the activation time. */
 371
 372                         if (t->last_trigger.realtime > 0)
 373                                 b = t->last_trigger.realtime;
 374                         else {
 375                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 376                                         b = UNIT(t)->inactive_exit_timestamp.realtime;
 377                                 else
 378                                         b = ts.realtime;
 379                         }
 380
 381                         r = calendar_spec_next_usec(v->calendar_spec, b, &v->next_elapse);
 382                         if (r < 0)
 383                                 continue;
 384
 385                         if (!found_realtime)
 386                                 t->next_elapse_realtime = v->next_elapse;
 387                         else
 388                                 t->next_elapse_realtime = MIN(t->next_elapse_realtime, v->next_elapse);
 389
 390                         found_realtime = true;
 391
 392                 } else {
 393                         usec_t base;
 394
 395                         switch (v->base) {
 396
 397                         case TIMER_ACTIVE:
 398                                 if (state_translation_table[t->state] == UNIT_ACTIVE)
 399                                         base = UNIT(t)->inactive_exit_timestamp.monotonic;
 400                                 else
 401                                         base = ts.monotonic;
 402                                 break;
 403
 404                         case TIMER_BOOT:
 405                                 if (detect_container() <= 0) {
 406                                         /* CLOCK_MONOTONIC equals the uptime on Linux */
 407                                         base = 0;
 408                                         break;
 409                                 }
 410                                 /* In a container we don't want to include the time the host
 411                                  * was already up when the container started, so count from
 412                                  * our own startup. */
 413                                 _fallthrough_;
 414                         case TIMER_STARTUP:
 415                                 base = UNIT(t)->manager->timestamps[MANAGER_TIMESTAMP_USERSPACE].monotonic;
 416                                 break;
 417
 418                         case TIMER_UNIT_ACTIVE:
 419                                 leave_around = true;
 420                                 base = trigger->inactive_exit_timestamp.monotonic;
 421
 422                                 if (base <= 0)
 423                                         base = t->last_trigger.monotonic;
 424
 425                                 if (base <= 0)
 426                                         continue;
 427                                 base = MAX(base, t->last_trigger.monotonic);
 428
 429                                 break;
 430
 431                         case TIMER_UNIT_INACTIVE:
 432                                 leave_around = true;
 433                                 base = trigger->inactive_enter_timestamp.monotonic;
 434
 435                                 if (base <= 0)
 436                                         base = t->last_trigger.monotonic;
 437
 438                                 if (base <= 0)
 439                                         continue;
 440                                 base = MAX(base, t->last_trigger.monotonic);
 441
 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 (!initial &&
 451                             v->next_elapse < triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)) &&
 452                             IN_SET(v->base, TIMER_ACTIVE, TIMER_BOOT, TIMER_STARTUP)) {
 453                                 /* This is a one time trigger, disable it now */
 454                                 v->disabled = true;
 455                                 continue;
 456                         }
 457
 458                         if (!found_monotonic)
 459                                 t->next_elapse_monotonic_or_boottime = v->next_elapse;
 460                         else
 461                                 t->next_elapse_monotonic_or_boottime = MIN(t->next_elapse_monotonic_or_boottime, v->next_elapse);
 462
 463                         found_monotonic = true;
 464                 }
 465         }
 466
 467         if (!found_monotonic && !found_realtime) {
 468                 log_unit_debug(UNIT(t), "Timer is elapsed.");
 469                 timer_enter_elapsed(t, leave_around);
 470                 return;
 471         }
 472
 473         if (found_monotonic) {
 474                 char buf[FORMAT_TIMESPAN_MAX];
 475                 usec_t left;
 476
 477                 add_random(t, &t->next_elapse_monotonic_or_boottime);
 478
 479                 left = usec_sub_unsigned(t->next_elapse_monotonic_or_boottime, triple_timestamp_by_clock(&ts, TIMER_MONOTONIC_CLOCK(t)));
 480                 log_unit_debug(UNIT(t), "Monotonic timer elapses in %s.", format_timespan(buf, sizeof(buf), left, 0));
 481
 482                 if (t->monotonic_event_source) {
 483                         r = sd_event_source_set_time(t->monotonic_event_source, t->next_elapse_monotonic_or_boottime);
 484                         if (r < 0)
 485                                 goto fail;
 486
 487                         r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_ONESHOT);
 488                         if (r < 0)
 489                                 goto fail;
 490                 } else {
 491
 492                         r = sd_event_add_time(
 493                                         UNIT(t)->manager->event,
 494                                         &t->monotonic_event_source,
 495                                         t->wake_system ? CLOCK_BOOTTIME_ALARM : CLOCK_MONOTONIC,
 496                                         t->next_elapse_monotonic_or_boottime, t->accuracy_usec,
 497                                         timer_dispatch, t);
 498                         if (r < 0)
 499                                 goto fail;
 500
 501                         (void) sd_event_source_set_description(t->monotonic_event_source, "timer-monotonic");
 502                 }
 503
 504         } else if (t->monotonic_event_source) {
 505
 506                 r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_OFF);
 507                 if (r < 0)
 508                         goto fail;
 509         }
 510
 511         if (found_realtime) {
 512                 char buf[FORMAT_TIMESTAMP_MAX];
 513
 514                 add_random(t, &t->next_elapse_realtime);
 515
 516                 log_unit_debug(UNIT(t), "Realtime timer elapses at %s.", format_timestamp(buf, sizeof(buf), t->next_elapse_realtime));
 517
 518                 if (t->realtime_event_source) {
 519                         r = sd_event_source_set_time(t->realtime_event_source, t->next_elapse_realtime);
 520                         if (r < 0)
 521                                 goto fail;
 522
 523                         r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_ONESHOT);
 524                         if (r < 0)
 525                                 goto fail;
 526                 } else {
 527                         r = sd_event_add_time(
 528                                         UNIT(t)->manager->event,
 529                                         &t->realtime_event_source,
 530                                         t->wake_system ? CLOCK_REALTIME_ALARM : CLOCK_REALTIME,
 531                                         t->next_elapse_realtime, t->accuracy_usec,
 532                                         timer_dispatch, t);
 533                         if (r < 0)
 534                                 goto fail;
 535
 536                         (void) sd_event_source_set_description(t->realtime_event_source, "timer-realtime");
 537                 }
 538
 539         } else if (t->realtime_event_source) {
 540
 541                 r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_OFF);
 542                 if (r < 0)
 543                         goto fail;
 544         }
 545
 546         timer_set_state(t, TIMER_WAITING);
 547         return;
 548
 549 fail:
 550         log_unit_warning_errno(UNIT(t), r, "Failed to enter waiting state: %m");
 551         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 552 }
 553
 554 static void timer_enter_running(Timer *t) {
 555         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 556         Unit *trigger;
 557         int r;
 558
 559         assert(t);
 560
 561         /* Don't start job if we are supposed to go down */
 562         if (unit_stop_pending(UNIT(t)))
 563                 return;
 564
 565         trigger = UNIT_TRIGGER(UNIT(t));
 566         if (!trigger) {
 567                 log_unit_error(UNIT(t), "Unit to trigger vanished.");
 568                 timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 569                 return;
 570         }
 571
 572         r = manager_add_job(UNIT(t)->manager, JOB_START, trigger, JOB_REPLACE, &error, NULL);
 573         if (r < 0)
 574                 goto fail;
 575
 576         dual_timestamp_get(&t->last_trigger);
 577
 578         if (t->stamp_path)
 579                 touch_file(t->stamp_path, true, t->last_trigger.realtime, UID_INVALID, GID_INVALID, MODE_INVALID);
 580
 581         timer_set_state(t, TIMER_RUNNING);
 582         return;
 583
 584 fail:
 585         log_unit_warning(UNIT(t), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
 586         timer_enter_dead(t, TIMER_FAILURE_RESOURCES);
 587 }
 588
 589 static int timer_start(Unit *u) {
 590         Timer *t = TIMER(u);
 591         TimerValue *v;
 592         Unit *trigger;
 593         int r;
 594
 595         assert(t);
 596         assert(IN_SET(t->state, TIMER_DEAD, TIMER_FAILED));
 597
 598         trigger = UNIT_TRIGGER(u);
 599         if (!trigger || trigger->load_state != UNIT_LOADED) {
 600                 log_unit_error(u, "Refusing to start, unit to trigger not loaded.");
 601                 return -ENOENT;
 602         }
 603
 604         r = unit_start_limit_test(u);
 605         if (r < 0) {
 606                 timer_enter_dead(t, TIMER_FAILURE_START_LIMIT_HIT);
 607                 return r;
 608         }
 609
 610         r = unit_acquire_invocation_id(u);
 611         if (r < 0)
 612                 return r;
 613
 614         t->last_trigger = DUAL_TIMESTAMP_NULL;
 615
 616         /* Reenable all timers that depend on unit activation time */
 617         LIST_FOREACH(value, v, t->values)
 618                 if (v->base == TIMER_ACTIVE)
 619                         v->disabled = false;
 620
 621         if (t->stamp_path) {
 622                 struct stat st;
 623
 624                 if (stat(t->stamp_path, &st) >= 0) {
 625                         usec_t ft;
 626
 627                         /* Load the file timestamp, but only if it is actually in the past. If it is in the future,
 628                          * something is wrong with the system clock. */
 629
 630                         ft = timespec_load(&st.st_mtim);
 631                         if (ft < now(CLOCK_REALTIME))
 632                                 t->last_trigger.realtime = ft;
 633                         else {
 634                                 char z[FORMAT_TIMESTAMP_MAX];
 635
 636                                 log_unit_warning(u, "Not using persistent file timestamp %s as it is in the future.",
 637                                                  format_timestamp(z, sizeof(z), ft));
 638                         }
 639
 640                 } else if (errno == ENOENT)
 641                         /* The timer has never run before,
 642                          * make sure a stamp file exists.
 643                          */
 644                         (void) touch_file(t->stamp_path, true, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
 645         }
 646
 647         t->result = TIMER_SUCCESS;
 648         timer_enter_waiting(t, true);
 649         return 1;
 650 }
 651
 652 static int timer_stop(Unit *u) {
 653         Timer *t = TIMER(u);
 654
 655         assert(t);
 656         assert(IN_SET(t->state, TIMER_WAITING, TIMER_RUNNING, TIMER_ELAPSED));
 657
 658         timer_enter_dead(t, TIMER_SUCCESS);
 659         return 1;
 660 }
 661
 662 static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
 663         Timer *t = TIMER(u);
 664
 665         assert(u);
 666         assert(f);
 667         assert(fds);
 668
 669         unit_serialize_item(u, f, "state", timer_state_to_string(t->state));
 670         unit_serialize_item(u, f, "result", timer_result_to_string(t->result));
 671
 672         if (t->last_trigger.realtime > 0)
 673                 unit_serialize_item_format(u, f, "last-trigger-realtime", "%" PRIu64, t->last_trigger.realtime);
 674
 675         if (t->last_trigger.monotonic > 0)
 676                 unit_serialize_item_format(u, f, "last-trigger-monotonic", "%" PRIu64, t->last_trigger.monotonic);
 677
 678         return 0;
 679 }
 680
 681 static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 682         Timer *t = TIMER(u);
 683         int r;
 684
 685         assert(u);
 686         assert(key);
 687         assert(value);
 688         assert(fds);
 689
 690         if (streq(key, "state")) {
 691                 TimerState state;
 692
 693                 state = timer_state_from_string(value);
 694                 if (state < 0)
 695                         log_unit_debug(u, "Failed to parse state value: %s", value);
 696                 else
 697                         t->deserialized_state = state;
 698         } else if (streq(key, "result")) {
 699                 TimerResult f;
 700
 701                 f = timer_result_from_string(value);
 702                 if (f < 0)
 703                         log_unit_debug(u, "Failed to parse result value: %s", value);
 704                 else if (f != TIMER_SUCCESS)
 705                         t->result = f;
 706         } else if (streq(key, "last-trigger-realtime")) {
 707
 708                 r = safe_atou64(value, &t->last_trigger.realtime);
 709                 if (r < 0)
 710                         log_unit_debug(u, "Failed to parse last-trigger-realtime value: %s", value);
 711
 712         } else if (streq(key, "last-trigger-monotonic")) {
 713
 714                 r = safe_atou64(value, &t->last_trigger.monotonic);
 715                 if (r < 0)
 716                         log_unit_debug(u, "Failed to parse last-trigger-monotonic value: %s", value);
 717
 718         } else
 719                 log_unit_debug(u, "Unknown serialization key: %s", key);
 720
 721         return 0;
 722 }
 723
 724 _pure_ static UnitActiveState timer_active_state(Unit *u) {
 725         assert(u);
 726
 727         return state_translation_table[TIMER(u)->state];
 728 }
 729
 730 _pure_ static const char *timer_sub_state_to_string(Unit *u) {
 731         assert(u);
 732
 733         return timer_state_to_string(TIMER(u)->state);
 734 }
 735
 736 static int timer_dispatch(sd_event_source *s, uint64_t usec, void *userdata) {
 737         Timer *t = TIMER(userdata);
 738
 739         assert(t);
 740
 741         if (t->state != TIMER_WAITING)
 742                 return 0;
 743
 744         log_unit_debug(UNIT(t), "Timer elapsed.");
 745         timer_enter_running(t);
 746         return 0;
 747 }
 748
 749 static void timer_trigger_notify(Unit *u, Unit *other) {
 750         Timer *t = TIMER(u);
 751         TimerValue *v;
 752
 753         assert(u);
 754         assert(other);
 755
 756         if (other->load_state != UNIT_LOADED)
 757                 return;
 758
 759         /* Reenable all timers that depend on unit state */
 760         LIST_FOREACH(value, v, t->values)
 761                 if (IN_SET(v->base, TIMER_UNIT_ACTIVE, TIMER_UNIT_INACTIVE))
 762                         v->disabled = false;
 763
 764         switch (t->state) {
 765
 766         case TIMER_WAITING:
 767         case TIMER_ELAPSED:
 768
 769                 /* Recalculate sleep time */
 770                 timer_enter_waiting(t, false);
 771                 break;
 772
 773         case TIMER_RUNNING:
 774
 775                 if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
 776                         log_unit_debug(UNIT(t), "Got notified about unit deactivation.");
 777                         timer_enter_waiting(t, false);
 778                 }
 779                 break;
 780
 781         case TIMER_DEAD:
 782         case TIMER_FAILED:
 783                 break;
 784
 785         default:
 786                 assert_not_reached("Unknown timer state");
 787         }
 788 }
 789
 790 static void timer_reset_failed(Unit *u) {
 791         Timer *t = TIMER(u);
 792
 793         assert(t);
 794
 795         if (t->state == TIMER_FAILED)
 796                 timer_set_state(t, TIMER_DEAD);
 797
 798         t->result = TIMER_SUCCESS;
 799 }
 800
 801 static void timer_time_change(Unit *u) {
 802         Timer *t = TIMER(u);
 803         usec_t ts;
 804
 805         assert(u);
 806
 807         if (t->state != TIMER_WAITING)
 808                 return;
 809
 810         /* If we appear to have triggered in the future, the system clock must
 811          * have been set backwards.  So let's rewind our own clock and allow
 812          * the future trigger(s) to happen again :).  Exactly the same as when
 813          * you start a timer unit with Persistent=yes. */
 814         ts = now(CLOCK_REALTIME);
 815         if (t->last_trigger.realtime > ts)
 816                 t->last_trigger.realtime = ts;
 817
 818         log_unit_debug(u, "Time change, recalculating next elapse.");
 819         timer_enter_waiting(t, false);
 820 }
 821
 822 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
 823         [TIMER_ACTIVE] = "OnActiveSec",
 824         [TIMER_BOOT] = "OnBootSec",
 825         [TIMER_STARTUP] = "OnStartupSec",
 826         [TIMER_UNIT_ACTIVE] = "OnUnitActiveSec",
 827         [TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec",
 828         [TIMER_CALENDAR] = "OnCalendar"
 829 };
 830
 831 DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
 832
 833 static const char* const timer_result_table[_TIMER_RESULT_MAX] = {
 834         [TIMER_SUCCESS] = "success",
 835         [TIMER_FAILURE_RESOURCES] = "resources",
 836         [TIMER_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
 837 };
 838
 839 DEFINE_STRING_TABLE_LOOKUP(timer_result, TimerResult);
 840
 841 const UnitVTable timer_vtable = {
 842         .object_size = sizeof(Timer),
 843
 844         .sections =
 845                 "Unit\0"
 846                 "Timer\0"
 847                 "Install\0",
 848         .private_section = "Timer",
 849
 850         .init = timer_init,
 851         .done = timer_done,
 852         .load = timer_load,
 853
 854         .coldplug = timer_coldplug,
 855
 856         .dump = timer_dump,
 857
 858         .start = timer_start,
 859         .stop = timer_stop,
 860
 861         .serialize = timer_serialize,
 862         .deserialize_item = timer_deserialize_item,
 863
 864         .active_state = timer_active_state,
 865         .sub_state_to_string = timer_sub_state_to_string,
 866
 867         .trigger_notify = timer_trigger_notify,
 868
 869         .reset_failed = timer_reset_failed,
 870         .time_change = timer_time_change,
 871
 872         .bus_vtable = bus_timer_vtable,
 873         .bus_set_property = bus_timer_set_property,
 874
 875         .can_transient = true,
 876 };