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_load(Unit *u) {
  77         Timer *t = TIMER(u);
  78         int r;
  79
  80         assert(u);
  81         assert(u->meta.load_state == UNIT_STUB);
  82
  83         if ((r = unit_load_fragment_and_dropin(u)) < 0)
  84                 return r;
  85
  86         if (u->meta.load_state == UNIT_LOADED) {
  87
  88                 if (!t->unit)
  89                         if ((r = unit_load_related_unit(u, ".service", &t->unit)))
  90                                 return r;
  91
  92                 if ((r = unit_add_dependency(u, UNIT_BEFORE, t->unit, true)) < 0)
  93                         return r;
  94
  95                 /* Timers shouldn't stay around on shutdown */
  96                 if (t->meta.default_dependencies)
  97                         if ((r = unit_add_two_dependencies_by_name(u, UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true)) < 0)
  98                                 return r;
  99         }
 100
 101         return timer_verify(t);
 102 }
 103
 104 static void timer_dump(Unit *u, FILE *f, const char *prefix) {
 105         Timer *t = TIMER(u);
 106         const char *prefix2;
 107         char *p2;
 108         TimerValue *v;
 109         char
 110                 timespan1[FORMAT_TIMESPAN_MAX];
 111
 112         p2 = strappend(prefix, "\t");
 113         prefix2 = p2 ? p2 : prefix;
 114
 115         fprintf(f,
 116                 "%sTimer State: %s\n"
 117                 "%sUnit: %s\n",
 118                 prefix, timer_state_to_string(t->state),
 119                 prefix, t->unit->meta.id);
 120
 121         LIST_FOREACH(value, v, t->values)
 122                 fprintf(f,
 123                         "%s%s: %s\n",
 124                         prefix,
 125                         timer_base_to_string(v->base),
 126                         strna(format_timespan(timespan1, sizeof(timespan1), v->value)));
 127
 128         free(p2);
 129 }
 130
 131 static void timer_set_state(Timer *t, TimerState state) {
 132         TimerState old_state;
 133         assert(t);
 134
 135         old_state = t->state;
 136         t->state = state;
 137
 138         if (state != TIMER_WAITING)
 139                 unit_unwatch_timer(UNIT(t), &t->timer_watch);
 140
 141         if (state != old_state)
 142                 log_debug("%s changed %s -> %s",
 143                           t->meta.id,
 144                           timer_state_to_string(old_state),
 145                           timer_state_to_string(state));
 146
 147         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state]);
 148 }
 149
 150 static void timer_enter_waiting(Timer *t, bool initial);
 151
 152 static int timer_coldplug(Unit *u) {
 153         Timer *t = TIMER(u);
 154
 155         assert(t);
 156         assert(t->state == TIMER_DEAD);
 157
 158         if (t->deserialized_state != t->state) {
 159
 160                 if (t->deserialized_state == TIMER_WAITING ||
 161                     t->deserialized_state == TIMER_RUNNING ||
 162                     t->deserialized_state == TIMER_ELAPSED)
 163                         timer_enter_waiting(t, false);
 164                 else
 165                         timer_set_state(t, t->deserialized_state);
 166         }
 167
 168         return 0;
 169 }
 170
 171 static void timer_enter_dead(Timer *t, bool success) {
 172         assert(t);
 173
 174         if (!success)
 175                 t->failure = true;
 176
 177         timer_set_state(t, t->failure ? TIMER_MAINTENANCE : TIMER_DEAD);
 178 }
 179
 180 static void timer_enter_waiting(Timer *t, bool initial) {
 181         TimerValue *v;
 182         usec_t base = 0, delay, n;
 183         bool found = false;
 184         int r;
 185
 186         n = now(CLOCK_MONOTONIC);
 187
 188         LIST_FOREACH(value, v, t->values) {
 189
 190                 if (v->disabled)
 191                         continue;
 192
 193                 switch (v->base) {
 194
 195                 case TIMER_ACTIVE:
 196                         if (state_translation_table[t->state] == UNIT_ACTIVE) {
 197                                 base = t->meta.inactive_exit_timestamp.monotonic;
 198                         } else
 199                                 base = n;
 200                         break;
 201
 202                 case TIMER_BOOT:
 203                         /* CLOCK_MONOTONIC equals the uptime on Linux */
 204                         base = 0;
 205                         break;
 206
 207                 case TIMER_STARTUP:
 208                         base = t->meta.manager->startup_timestamp.monotonic;
 209                         break;
 210
 211                 case TIMER_UNIT_ACTIVE:
 212
 213                         if (t->unit->meta.inactive_exit_timestamp.monotonic <= 0)
 214                                 continue;
 215
 216                         base = t->unit->meta.inactive_exit_timestamp.monotonic;
 217                         break;
 218
 219                 case TIMER_UNIT_INACTIVE:
 220
 221                         if (t->unit->meta.inactive_enter_timestamp.monotonic <= 0)
 222                                 continue;
 223
 224                         base = t->unit->meta.inactive_enter_timestamp.monotonic;
 225                         break;
 226
 227                 default:
 228                         assert_not_reached("Unknown timer base");
 229                 }
 230
 231                 v->next_elapse = base + v->value;
 232
 233                 if (!initial && v->next_elapse < n) {
 234                         v->disabled = true;
 235                         continue;
 236                 }
 237
 238                 if (!found)
 239                         t->next_elapse = v->next_elapse;
 240                 else
 241                         t->next_elapse = MIN(t->next_elapse, v->next_elapse);
 242
 243                 found = true;
 244         }
 245
 246         if (!found) {
 247                 timer_set_state(t, TIMER_ELAPSED);
 248                 return;
 249         }
 250
 251         delay = n < t->next_elapse ? t->next_elapse - n : 0;
 252
 253         if ((r = unit_watch_timer(UNIT(t), delay, &t->timer_watch)) < 0)
 254                 goto fail;
 255
 256         timer_set_state(t, TIMER_WAITING);
 257         return;
 258
 259 fail:
 260         log_warning("%s failed to enter waiting state: %s", t->meta.id, strerror(-r));
 261         timer_enter_dead(t, false);
 262 }
 263
 264 static void timer_enter_running(Timer *t) {
 265         DBusError error;
 266         int r;
 267
 268         assert(t);
 269         dbus_error_init(&error);
 270
 271         /* Don't start job if we are supposed to go down */
 272         if (t->meta.job && t->meta.job->type == JOB_STOP)
 273                 return;
 274
 275         if ((r = manager_add_job(t->meta.manager, JOB_START, t->unit, JOB_REPLACE, true, &error, NULL)) < 0)
 276                 goto fail;
 277
 278         timer_set_state(t, TIMER_RUNNING);
 279         return;
 280
 281 fail:
 282         log_warning("%s failed to queue unit startup job: %s", t->meta.id, bus_error(&error, r));
 283         timer_enter_dead(t, false);
 284
 285         dbus_error_free(&error);
 286 }
 287
 288 static int timer_start(Unit *u) {
 289         Timer *t = TIMER(u);
 290
 291         assert(t);
 292         assert(t->state == TIMER_DEAD || t->state == TIMER_MAINTENANCE);
 293
 294         if (t->unit->meta.load_state != UNIT_LOADED)
 295                 return -ENOENT;
 296
 297         t->failure = false;
 298         timer_enter_waiting(t, true);
 299         return 0;
 300 }
 301
 302 static int timer_stop(Unit *u) {
 303         Timer *t = TIMER(u);
 304
 305         assert(t);
 306         assert(t->state == TIMER_WAITING || t->state == TIMER_RUNNING || t->state == TIMER_ELAPSED);
 307
 308         timer_enter_dead(t, true);
 309         return 0;
 310 }
 311
 312 static int timer_serialize(Unit *u, FILE *f, FDSet *fds) {
 313         Timer *t = TIMER(u);
 314
 315         assert(u);
 316         assert(f);
 317         assert(fds);
 318
 319         unit_serialize_item(u, f, "state", timer_state_to_string(t->state));
 320
 321         return 0;
 322 }
 323
 324 static int timer_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 325         Timer *t = TIMER(u);
 326
 327         assert(u);
 328         assert(key);
 329         assert(value);
 330         assert(fds);
 331
 332         if (streq(key, "state")) {
 333                 TimerState state;
 334
 335                 if ((state = timer_state_from_string(value)) < 0)
 336                         log_debug("Failed to parse state value %s", value);
 337                 else
 338                         t->deserialized_state = state;
 339         } else
 340                 log_debug("Unknown serialization key '%s'", key);
 341
 342         return 0;
 343 }
 344
 345 static UnitActiveState timer_active_state(Unit *u) {
 346         assert(u);
 347
 348         return state_translation_table[TIMER(u)->state];
 349 }
 350
 351 static const char *timer_sub_state_to_string(Unit *u) {
 352         assert(u);
 353
 354         return timer_state_to_string(TIMER(u)->state);
 355 }
 356
 357 static void timer_timer_event(Unit *u, uint64_t elapsed, Watch *w) {
 358         Timer *t = TIMER(u);
 359
 360         assert(t);
 361         assert(elapsed == 1);
 362
 363         if (t->state != TIMER_WAITING)
 364                 return;
 365
 366         log_debug("Timer elapsed on %s", u->meta.id);
 367         timer_enter_running(t);
 368 }
 369
 370 void timer_unit_notify(Unit *u, UnitActiveState new_state) {
 371         char *n;
 372         int r;
 373         Iterator i;
 374
 375         if (u->meta.type == UNIT_TIMER)
 376                 return;
 377
 378         SET_FOREACH(n, u->meta.names, i) {
 379                 char *k;
 380                 Unit *p;
 381                 Timer *t;
 382                 TimerValue *v;
 383
 384                 if (!(k = unit_name_change_suffix(n, ".timer"))) {
 385                         r = -ENOMEM;
 386                         goto fail;
 387                 }
 388
 389                 p = manager_get_unit(u->meta.manager, k);
 390                 free(k);
 391
 392                 if (!p)
 393                         continue;
 394
 395                 if (p->meta.load_state != UNIT_LOADED)
 396                         continue;
 397
 398                 t = TIMER(p);
 399
 400                 if (t->unit != u)
 401                         continue;
 402
 403                 /* Reenable all timers that depend on unit state */
 404                 LIST_FOREACH(value, v, t->values)
 405                         if (v->base == TIMER_UNIT_ACTIVE ||
 406                             v->base == TIMER_UNIT_INACTIVE)
 407                                 v->disabled = false;
 408
 409                 switch (t->state) {
 410
 411                 case TIMER_WAITING:
 412                 case TIMER_ELAPSED:
 413
 414                         /* Recalculate sleep time */
 415                         timer_enter_waiting(t, false);
 416                         break;
 417
 418                 case TIMER_RUNNING:
 419
 420                         if (UNIT_IS_INACTIVE_OR_MAINTENANCE(new_state)) {
 421                                 log_debug("%s got notified about unit deactivation.", t->meta.id);
 422                                 timer_enter_waiting(t, false);
 423                         }
 424
 425                         break;
 426
 427                 case TIMER_DEAD:
 428                 case TIMER_MAINTENANCE:
 429                         ;
 430
 431                 default:
 432                         assert_not_reached("Unknown timer state");
 433                 }
 434         }
 435
 436         return;
 437
 438 fail:
 439         log_error("Failed find timer unit: %s", strerror(-r));
 440 }
 441
 442 static const char* const timer_state_table[_TIMER_STATE_MAX] = {
 443         [TIMER_DEAD] = "dead",
 444         [TIMER_WAITING] = "waiting",
 445         [TIMER_RUNNING] = "running",
 446         [TIMER_ELAPSED] = "elapsed",
 447         [TIMER_MAINTENANCE] = "maintenance"
 448 };
 449
 450 DEFINE_STRING_TABLE_LOOKUP(timer_state, TimerState);
 451
 452 static const char* const timer_base_table[_TIMER_BASE_MAX] = {
 453         [TIMER_ACTIVE] = "OnActiveSec",
 454         [TIMER_BOOT] = "OnBootSec",
 455         [TIMER_STARTUP] = "OnStartupSec",
 456         [TIMER_UNIT_ACTIVE] = "OnUnitActiveSec",
 457         [TIMER_UNIT_INACTIVE] = "OnUnitInactiveSec"
 458 };
 459
 460 DEFINE_STRING_TABLE_LOOKUP(timer_base, TimerBase);
 461
 462 const UnitVTable timer_vtable = {
 463         .suffix = ".timer",
 464
 465         .init = timer_init,
 466         .done = timer_done,
 467         .load = timer_load,
 468
 469         .coldplug = timer_coldplug,
 470
 471         .dump = timer_dump,
 472
 473         .start = timer_start,
 474         .stop = timer_stop,
 475
 476         .serialize = timer_serialize,
 477         .deserialize_item = timer_deserialize_item,
 478
 479         .active_state = timer_active_state,
 480         .sub_state_to_string = timer_sub_state_to_string,
 481
 482         .timer_event = timer_timer_event,
 483
 484         .bus_message_handler = bus_timer_message_handler
 485 };