src/timer.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23
  24 #include "unit.h"
  25 #include "unit-name.h"
  26 #include "timer.h"
  27 #include "dbus-timer.h"
  28 #include "special.h"
  29 #include "bus-errors.h"
  30
  31 static const UnitActiveState state_translation_table[_TIMER_STATE_MAX] = {
  32         [TIMER_DEAD] = UNIT_INACTIVE,
  33         [TIMER_WAITING] = UNIT_ACTIVE,
  34         [TIMER_RUNNING] = UNIT_ACTIVE,
  35         [TIMER_ELAPSED] = UNIT_ACTIVE,
  36         [TIMER_MAINTENANCE] = UNIT_MAINTENANCE
  37 };
  38
  39 static void timer_init(Unit *u) {
  40         Timer *t = TIMER(u);
  41
  42         assert(u);
  43         assert(u->meta.load_state == UNIT_STUB);
  44
  45         t->next_elapse = (usec_t) -1;
  46 }
  47
  48 static void timer_done(Unit *u) {
  49         Timer *t = TIMER(u);
  50         TimerValue *v;
  51
  52         assert(t);
  53
  54         while ((v = t->values)) {
  55                 LIST_REMOVE(TimerValue, value, t->values, v);
  56                 free(v);
  57         }
  58
  59         unit_unwatch_timer(u, &t->timer_watch);
  60 }
  61
  62 static int timer_verify(Timer *t) {
  63         assert(t);
  64
  65         if (t->meta.load_state != UNIT_LOADED)
  66                 return 0;
  67
  68         if (!t->values) {
  69                 log_error("%s lacks value setting. Refusing.", t->meta.id);
  70                 return -EINVAL;
  71         }
  72
  73         return 0;
  74 }
  75
  76 static int timer_add_default_dependencies(Timer *t) {
  77         int r;
  78
  79         assert(t);
  80
  81         if (t->meta.manager->running_as == MANAGER_SYSTEM)
  82                 if ((r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true)) < 0)
  83                         return r;
  84
  85         return unit_add_two_dependencies_by_name(UNIT(t), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
  86 }
  87
  88 static int timer_load(Unit *u) {
  89         Timer *t = TIMER(u);
  90         int r;
  91
  92         assert(u);
  93         assert(u->meta.load_state == UNIT_STUB);
  94
  95         if ((r = unit_load_fragment_and_dropin(u)) < 0)
  96                 return r;
  97
  98         if (u->meta.load_state == UNIT_LOADED) {
  99
 100                 if (!t->unit)
 101                         if ((r = unit_load_related_unit(u, ".service", &t->unit)))
 102                                 return r;
 103
 104                 if ((r = unit_add_dependency(u, UNIT_BEFORE, t->unit, true)) < 0)
 105                         return r;
 106
 107                 if (t->meta.default_dependencies)
 108                         if ((r = timer_add_default_dependencies(t)) < 0)
 109                                 return r;
 110         }
 111
 112         return timer_verify(t);
 113 }
 114
 115 static void timer_dump(Unit *u, FILE *f, const char *prefix) {
 116         Timer *t = TIMER(u);
 117         const char *prefix2;
 118         char *p2;
 119         TimerValue *v;
 120         char
 121                 timespan1[FORMAT_TIMESPAN_MAX];
 122
 123         p2 = strappend(prefix, "\t");
 124         prefix2 = p2 ? p2 : prefix;
 125
 126         fprintf(f,
 127                 "%sTimer State: %s\n"
 128                 "%sUnit: %s\n",
 129                 prefix, timer_state_to_string(t->state),
 130                 prefix, t->unit->meta.id);
 131
 132         LIST_FOREACH(value, v, t->values)
 133                 fprintf(f,
 134                         "%s%s: %s\n",
 135                         prefix,
 136                         timer_base_to_string(v->base),
 137                         strna(format_timespan(timespan1, sizeof(timespan1), v->value)));
 138
 139         free(p2);
 140 }
 141
 142 static void timer_set_state(Timer *t, TimerState state) {
 143         TimerState old_state;
 144         assert(t);
 145
 146         old_state = t->state;
 147         t->state = state;
 148
 149         if (state != TIMER_WAITING)
 150                 unit_unwatch_timer(UNIT(t), &t->timer_watch);
 151
 152         if (state != old_state)
 153                 log_debug("%s changed %s -> %s",
 154                           t->meta.id,
 155                           timer_state_to_string(old_state),
 156                           timer_state_to_string(state));
 157
 158         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state]);
 159 }
 160
 161 static void timer_enter_waiting(Timer *t, bool initial);
 162
 163 static int timer_coldplug(Unit *u) {
 164         Timer *t = TIMER(u);
 165
 166         assert(t);
 167         assert(t->state == TIMER_DEAD);
 168
 169         if (t->deserialized_state != t->state) {
 170
 171                 if (t->deserialized_state == TIMER_WAITING ||
 172                     t->deserialized_state == TIMER_RUNNING ||
 173                     t->deserialized_state == TIMER_ELAPSED)
 174                         timer_enter_waiting(t, false);
 175                 else
 176                         timer_set_state(t, t->deserialized_state);
 177         }
 178
 179         return 0;
 180 }
 181
 182 static void timer_enter_dead(Timer *t, bool success) {
 183         assert(t);
 184
 185         if (!success)
 186                 t->failure = true;
 187
 188         timer_set_state(t, t->failure ? TIMER_MAINTENANCE : TIMER_DEAD);
 189 }
 190
 191 static void timer_enter_waiting(Timer *t, bool initial) {
 192         TimerValue *v;
 193         usec_t base = 0, delay, n;
 194         bool found = false;
 195         int r;
 196
 197         n = now(CLOCK_MONOTONIC);
 198
 199         LIST_FOREACH(value, v, t->values) {
 200
 201                 if (v->disabled)
 202                         continue;
 203
 204                 switch (v->base) {
 205
 206                 case TIMER_ACTIVE:
 207                         if (state_translation_table[t->state] == UNIT_ACTIVE) {
 208                                 base = t->meta.inactive_exit_timestamp.monotonic;
 209                         } else
 210                                 base = n;
 211                         break;
 212
 213                 case TIMER_BOOT:
 214                         /* CLOCK_MONOTONIC equals the uptime on Linux */
 215                         base = 0;
 216                         break;
 217
 218                 case TIMER_STARTUP:
 219                         base = t->meta.manager->startup_timestamp.monotonic;
 220                         break;
 221
 222                 case TIMER_UNIT_ACTIVE:
 223
 224                         if (t->unit->meta.inactive_exit_timestamp.monotonic <= 0)
 225                                 continue;
 226
 227                         base = t->unit->meta.inactive_exit_timestamp.monotonic;
 228                         break;
 229
 230                 case TIMER_UNIT_INACTIVE:
 231
 232                         if (t->unit->meta.inactive_enter_timestamp.monotonic <= 0)
 233                                 continue;
 234
 235                         base = t->unit->meta.inactive_enter_timestamp.monotonic;
 236                         break;
 237
 238                 default:
 239                         assert_not_reached("Unknown timer base");
 240                 }
 241
 242                 v->next_elapse = base + v->value;
 243
 244                 if (!initial && v->next_elapse < n) {
 245                         v->disabled = true;
 246                         continue;
 247                 }
 248
 249                 if (!found)
 250                         t->next_elapse = v->next_elapse;
 251                 else
 252                         t->next_elapse = MIN(t->next_elapse, v->next_elapse);
 253
 254                 found = true;
 255         }
 256
 257         if (!found) {
 258                 timer_set_state(t, TIMER_ELAPSED);
 259                 return;
 260         }
 261
 262         delay = n < t->next_elapse ? t->next_elapse - n : 0;
 263
 264         if ((r = unit_watch_timer(UNIT(t), delay, &t->timer_watch)) < 0)
 265                 goto fail;
 266
 267         timer_set_state(t, TIMER_WAITING);
 268         return;
 269
 270 fail:
 271         log_warning("%s failed to enter waiting state: %s", t->meta.id, strerror(-r));
 272         timer_enter_dead(t, false);
 273 }
 274
 275 static void timer_enter_running(Timer *t) {
 276         DBusError error;
 277         int r;
 278
 279         assert(t);
 280         dbus_error_init(&error);
 281
 282         /* Don't start job if we are supposed to go down */
 283         if (t->meta.job && t->meta.job->type == JOB_STOP)
 284                 return;
 285
 286         if ((r = manager_add_job(t->meta.manager, JOB_START, t->unit, JOB_REPLACE, true, &error, NULL)) < 0)
 287                 goto fail;
 288
 289         timer_set_state(t, TIMER_RUNNING);
 290         return;
 291
 292 fail:
 293         log_warning("%s failed to queue unit startup job: %s", t->meta.id, bus_error(&error, r));
 294         timer_enter_dead(t, false);
 295
 296         dbus_error_free(&error);
 297 }
 298
 299 static int timer_start(Unit *u) {
 300         Timer *t = TIMER(u);
 301
 302         assert(t);
 303         assert(t->state == TIMER_DEAD || t->state == TIMER_MAINTENANCE);
 304
 305         if (t->unit->meta.load_state != UNIT_LOADED)
 306                 return -ENOENT;
 307
 308         t->failure = false;
 309         timer_enter_waiting(t, true);
 310         return 0;
 311 }
 312
 313 static int timer_stop(Unit *u) {
 314         Timer *t = TIMER(u);
 315
 316         assert(t);
 317         assert(t->state == TIMER_WAITING || t->state == TIMER_RUNNING || t->state == TIMER_ELAPSED);
 318
 319         timer_enter_dead(t, true);
 320         return 0;
 321 }
 322
 323 static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
 324         Timer *t = TIMER(u);
 325
 326         assert(u);
 327         assert(f);
 328         assert(fds);
 329
 330         unit_serialize_item(u, f, "state", timer_state_to_string(t->state));
 331
 332         return 0;
 333 }
 334
 335 static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 336         Timer *t = TIMER(u);
 337
 338         assert(u);
 339         assert(key);
 340         assert(value);
 341         assert(fds);
 342
 343         if (streq(key, "state")) {
 344                 TimerState state;
 345
 346                 if ((state = timer_state_from_string(value)) < 0)
 347                         log_debug("Failed to parse state value %s", value);
 348                 else
 349                         t->deserialized_state = state;
 350         } else
 351                 log_debug("Unknown serialization key '%s'", key);
 352
 353         return 0;
 354 }
 355
 356 static UnitActiveState timer_active_state(Unit *u) {
 357         assert(u);
 358
 359         return state_translation_table[TIMER(u)->state];
 360 }
 361
 362 static const char *timer_sub_state_to_string(Unit *u) {
 363         assert(u);
 364
 365         return timer_state_to_string(TIMER(u)->state);
 366 }
 367
 368 static void timer_timer_event(Unit *u, uint64_t elapsed, Watch *w) {
 369         Timer *t = TIMER(u);
 370
 371         assert(t);
 372         assert(elapsed == 1);
 373
 374         if (t->state != TIMER_WAITING)
 375                 return;
 376
 377         log_debug("Timer elapsed on %s", u->meta.id);
 378         timer_enter_running(t);
 379 }
 380
 381 void timer_unit_notify(Unit *u, UnitActiveState new_state) {
 382         char *n;
 383         int r;
 384         Iterator i;
 385
 386         if (u->meta.type == UNIT_TIMER)
 387                 return;
 388
 389         SET_FOREACH(n, u->meta.names, i) {
 390                 char *k;
 391                 Unit *p;
 392                 Timer *t;
 393                 TimerValue *v;
 394
 395                 if (!(k = unit_name_change_suffix(n, ".timer"))) {
 396                         r = -ENOMEM;
 397                         goto fail;
 398                 }
 399
 400                 p = manager_get_unit(u->meta.manager, k);
 401                 free(k);
 402
 403                 if (!p)
 404                         continue;
 405
 406                 if (p->meta.load_state != UNIT_LOADED)
 407                         continue;
 408
 409                 t = TIMER(p);
 410
 411                 if (t->unit != u)
 412                         continue;
 413
 414                 /* Reenable all timers that depend on unit state */
 415                 LIST_FOREACH(value, v, t->values)
 416                         if (v->base == TIMER_UNIT_ACTIVE ||
 417                             v->base == TIMER_UNIT_INACTIVE)
 418                                 v->disabled = false;
 419
 420                 switch (t->state) {
 421
 422                 case TIMER_WAITING:
 423                 case TIMER_ELAPSED:
 424
 425                         /* Recalculate sleep time */
 426                         timer_enter_waiting(t, false);
 427                         break;
 428
 429                 case TIMER_RUNNING:
 430
 431                         if (UNIT_IS_INACTIVE_OR_MAINTENANCE(new_state)) {
 432                                 log_debug("%s got notified about unit deactivation.", t->meta.id);
 433                                 timer_enter_waiting(t, false);
 434                         }
 435
 436                         break;
 437
 438                 case TIMER_DEAD:
 439                 case TIMER_MAINTENANCE:
 440                         ;
 441
 442                 default:
 443                         assert_not_reached("Unknown timer state");
 444                 }
 445         }
 446
 447         return;
 448
 449 fail:
 450         log_error("Failed find timer unit: %s", strerror(-r));
 451 }
 452
 453 static void timer_reset_maintenance(Unit *u) {
 454         Timer *t = TIMER(u);
 455
 456         assert(t);
 457
 458         if (t->state == TIMER_MAINTENANCE)
 459                 timer_set_state(t, TIMER_DEAD);
 460
 461         t->failure = false;
 462 }
 463
 464 static const char* const timer_state_table[_TIMER_STATE_MAX] = {
 465         [TIMER_DEAD] = "dead",
 466         [TIMER_WAITING] = "waiting",
 467         [TIMER_RUNNING] = "running",
 468         [TIMER_ELAPSED] = "elapsed",
 469         [TIMER_MAINTENANCE] = "maintenance"
 470 };
 471
 472 DEFINE_STRING_TABLE_LOOKUP(timer_state, TimerState);
 473
 474 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
 475         [TIMER_ACTIVE] = "OnActiveSec",
 476         [TIMER_BOOT] = "OnBootSec",
 477         [TIMER_STARTUP] = "OnStartupSec",
 478         [TIMER_UNIT_ACTIVE] = "OnUnitActiveSec",
 479         [TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec"
 480 };
 481
 482 DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
 483
 484 const UnitVTable timer_vtable = {
 485         .suffix = ".timer",
 486
 487         .init = timer_init,
 488         .done = timer_done,
 489         .load = timer_load,
 490
 491         .coldplug = timer_coldplug,
 492
 493         .dump = timer_dump,
 494
 495         .start = timer_start,
 496         .stop = timer_stop,
 497
 498         .serialize = timer_serialize,
 499         .deserialize_item = timer_deserialize_item,
 500
 501         .active_state = timer_active_state,
 502         .sub_state_to_string = timer_sub_state_to_string,
 503
 504         .timer_event = timer_timer_event,
 505
 506         .reset_maintenance = timer_reset_maintenance,
 507
 508         .bus_message_handler = bus_timer_message_handler
 509 };