job.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <assert.h>
   4 #include <errno.h>
   5
   6 #include "macro.h"
   7 #include "job.h"
   8
   9 Job* job_new(Manager *m, JobType type, Unit *unit) {
  10         Job *j;
  11
  12         assert(m);
  13         assert(type < _JOB_TYPE_MAX);
  14         assert(unit);
  15
  16         if (!(j = new0(Job, 1)))
  17                 return NULL;
  18
  19         j->manager = m;
  20         j->id = m->current_job_id++;
  21         j->type = type;
  22         j->unit = unit;
  23
  24         /* We don't link it here, that's what job_dependency() is for */
  25
  26         return j;
  27 }
  28
  29 void job_free(Job *j) {
  30         assert(j);
  31
  32         /* Detach from next 'bigger' objects */
  33         if (j->installed) {
  34                 if (j->unit->meta.job == j)
  35                         j->unit->meta.job = NULL;
  36
  37                 hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
  38                 j->installed = false;
  39         }
  40
  41         /* Detach from next 'smaller' objects */
  42         manager_transaction_unlink_job(j->manager, j);
  43
  44         free(j);
  45 }
  46
  47 JobDependency* job_dependency_new(Job *subject, Job *object, bool matters) {
  48         JobDependency *l;
  49
  50         assert(object);
  51
  52         /* Adds a new job link, which encodes that the 'subject' job
  53          * needs the 'object' job in some way. If 'subject' is NULL
  54          * this means the 'anchor' job (i.e. the one the user
  55          * explcitily asked for) is the requester. */
  56
  57         if (!(l = new0(JobDependency, 1)))
  58                 return NULL;
  59
  60         l->subject = subject;
  61         l->object = object;
  62         l->matters = matters;
  63
  64         if (subject)
  65                 LIST_PREPEND(JobDependency, subject, subject->subject_list, l);
  66         else
  67                 LIST_PREPEND(JobDependency, subject, object->manager->transaction_anchor, l);
  68
  69         LIST_PREPEND(JobDependency, object, object->object_list, l);
  70
  71         return l;
  72 }
  73
  74 void job_dependency_free(JobDependency *l) {
  75         assert(l);
  76
  77         if (l->subject)
  78                 LIST_REMOVE(JobDependency, subject, l->subject->subject_list, l);
  79         else
  80                 LIST_REMOVE(JobDependency, subject, l->object->manager->transaction_anchor, l);
  81
  82         LIST_REMOVE(JobDependency, object, l->object->object_list, l);
  83
  84         free(l);
  85 }
  86
  87 void job_dependency_delete(Job *subject, Job *object, bool *matters) {
  88         JobDependency *l;
  89
  90         assert(object);
  91
  92         LIST_FOREACH(object, l, object->object_list) {
  93                 assert(l->object == object);
  94
  95                 if (l->subject == subject)
  96                         break;
  97         }
  98
  99         if (!l) {
 100                 if (matters)
 101                         *matters = false;
 102                 return;
 103         }
 104
 105         if (matters)
 106                 *matters = l->matters;
 107
 108         job_dependency_free(l);
 109 }
 110
 111 const char* job_type_to_string(JobType t) {
 112
 113         static const char* const job_type_table[_JOB_TYPE_MAX] = {
 114                 [JOB_START] = "start",
 115                 [JOB_VERIFY_ACTIVE] = "verify-active",
 116                 [JOB_STOP] = "stop",
 117                 [JOB_RELOAD] = "reload",
 118                 [JOB_RELOAD_OR_START] = "reload-or-start",
 119                 [JOB_RESTART] = "restart",
 120                 [JOB_TRY_RESTART] = "try-restart",
 121         };
 122
 123         if (t < 0 || t >= _JOB_TYPE_MAX)
 124                 return "n/a";
 125
 126         return job_type_table[t];
 127 }
 128
 129 void job_dump(Job *j, FILE*f, const char *prefix) {
 130
 131         static const char* const job_state_table[_JOB_STATE_MAX] = {
 132                 [JOB_WAITING] = "waiting",
 133                 [JOB_RUNNING] = "running"
 134         };
 135
 136         assert(j);
 137         assert(f);
 138
 139         fprintf(f,
 140                 "%s→ Job %u:\n"
 141                 "%s\tAction: %s → %s\n"
 142                 "%s\tState: %s\n"
 143                 "%s\tForced: %s\n",
 144                 prefix, j->id,
 145                 prefix, unit_id(j->unit), job_type_to_string(j->type),
 146                 prefix, job_state_table[j->state],
 147                 prefix, yes_no(j->forced));
 148 }
 149
 150 bool job_is_anchor(Job *j) {
 151         JobDependency *l;
 152
 153         assert(j);
 154
 155         LIST_FOREACH(object, l, j->object_list)
 156                 if (!l->subject)
 157                         return true;
 158
 159         return false;
 160 }
 161
 162 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
 163         return
 164                 (a == c && b == d) ||
 165                 (a == d && b == c);
 166 }
 167
 168 int job_type_merge(JobType *a, JobType b) {
 169         if (*a == b)
 170                 return 0;
 171
 172         /* Merging is associative! a merged with b merged with c is
 173          * the same as a merged with c merged with b. */
 174
 175         /* Mergeability is transitive! if a can be merged with b and b
 176          * with c then a also with c */
 177
 178         /* Also, if a merged with b cannot be merged with c, then
 179          * either a or b cannot be merged with c either */
 180
 181         if (types_match(*a, b, JOB_START, JOB_VERIFY_ACTIVE))
 182                 *a = JOB_START;
 183         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
 184                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
 185                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD_OR_START) ||
 186                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
 187                 *a = JOB_RELOAD_OR_START;
 188         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
 189                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
 190                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RESTART) ||
 191                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
 192                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
 193                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
 194                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
 195                 *a = JOB_RESTART;
 196         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD))
 197                 *a = JOB_RELOAD;
 198         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_TRY_RESTART) ||
 199                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
 200                 *a = JOB_TRY_RESTART;
 201         else
 202                 return -EEXIST;
 203
 204         return 0;
 205 }
 206
 207 bool job_type_is_mergeable(JobType a, JobType b) {
 208         return job_type_merge(&a, b) >= 0;
 209 }
 210
 211 bool job_type_is_superset(JobType a, JobType b) {
 212
 213         /* Checks whether operation a is a "superset" of b in its
 214          * actions */
 215
 216         if (a == b)
 217                 return true;
 218
 219         switch (a) {
 220                 case JOB_START:
 221                         return b == JOB_VERIFY_ACTIVE;
 222
 223                 case JOB_RELOAD:
 224                         return
 225                                 b == JOB_VERIFY_ACTIVE;
 226
 227                 case JOB_RELOAD_OR_START:
 228                         return
 229                                 b == JOB_RELOAD ||
 230                                 b == JOB_START ||
 231                                 b == JOB_VERIFY_ACTIVE;
 232
 233                 case JOB_RESTART:
 234                         return
 235                                 b == JOB_START ||
 236                                 b == JOB_VERIFY_ACTIVE ||
 237                                 b == JOB_RELOAD ||
 238                                 b == JOB_RELOAD_OR_START ||
 239                                 b == JOB_TRY_RESTART;
 240
 241                 case JOB_TRY_RESTART:
 242                         return
 243                                 b == JOB_VERIFY_ACTIVE ||
 244                                 b == JOB_RELOAD;
 245                 default:
 246                         return false;
 247
 248         }
 249 }
 250
 251 bool job_type_is_conflicting(JobType a, JobType b) {
 252         assert(a >= 0 && a < _JOB_TYPE_MAX);
 253         assert(b >= 0 && b < _JOB_TYPE_MAX);
 254
 255         return (a == JOB_STOP) != (b == JOB_STOP);
 256 }
 257
 258 bool job_is_runnable(Job *j) {
 259         Iterator i;
 260         Unit *other;
 261
 262         assert(j);
 263         assert(j->installed);
 264
 265         /* Checks whether there is any job running for the units this
 266          * job needs to be running after (in the case of a 'positive'
 267          * job type) or before (in the case of a 'negative' job type
 268          * . */
 269
 270         if (j->type == JOB_START ||
 271             j->type == JOB_VERIFY_ACTIVE ||
 272             j->type == JOB_RELOAD ||
 273             j->type == JOB_RELOAD_OR_START) {
 274
 275                 /* Immediate result is that the job is or might be
 276                  * started. In this case lets wait for the
 277                  * dependencies, regardless whether they are
 278                  * starting or stopping something. */
 279
 280                 SET_FOREACH(other, j->unit->meta.dependencies[UNIT_AFTER], i)
 281                         if (other->meta.job)
 282                                 return false;
 283         }
 284
 285         /* Also, if something else is being stopped and we should
 286          * change state after it, then lets wait. */
 287
 288         SET_FOREACH(other, j->unit->meta.dependencies[UNIT_BEFORE], i)
 289                 if (other->meta.job &&
 290                     (other->meta.job->type == JOB_STOP ||
 291                      other->meta.job->type == JOB_RESTART ||
 292                      other->meta.job->type == JOB_TRY_RESTART))
 293                         return false;
 294
 295         /* This means that for a service a and a service b where b
 296          * shall be started after a:
 297          *
 298          *  start a + start b → 1st step start a, 2nd step start b
 299          *  start a + stop b  → 1st step stop b,  2nd step start a
 300          *  stop a  + start b → 1st step stop a,  2nd step start b
 301          *  stop a  + stop b  → 1st step stop b,  2nd step stop a
 302          *
 303          *  This has the side effect that restarts are properly
 304          *  synchronized too. */
 305
 306         return true;
 307 }
 308
 309 int job_run_and_invalidate(Job *j) {
 310         int r;
 311
 312         assert(j);
 313         assert(j->installed);
 314
 315         if (j->in_run_queue) {
 316                 LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
 317                 j->in_run_queue = false;
 318         }
 319
 320         if (j->state != JOB_WAITING)
 321                 return 0;
 322
 323         if (!job_is_runnable(j))
 324                 return -EAGAIN;
 325
 326         j->state = JOB_RUNNING;
 327
 328         switch (j->type) {
 329
 330                 case JOB_START:
 331                         r = unit_start(j->unit);
 332                         if (r == -EBADR)
 333                                 r = 0;
 334                         break;
 335
 336                 case JOB_VERIFY_ACTIVE: {
 337                         UnitActiveState t = unit_active_state(j->unit);
 338                         if (UNIT_IS_ACTIVE_OR_RELOADING(t))
 339                                 r = -EALREADY;
 340                         else if (t == UNIT_ACTIVATING)
 341                                 r = -EAGAIN;
 342                         else
 343                                 r = -ENOEXEC;
 344                         break;
 345                 }
 346
 347                 case JOB_STOP:
 348                         r = unit_stop(j->unit);
 349                         break;
 350
 351                 case JOB_RELOAD:
 352                         r = unit_reload(j->unit);
 353                         break;
 354
 355                 case JOB_RELOAD_OR_START:
 356                         if (unit_active_state(j->unit) == UNIT_ACTIVE)
 357                                 r = unit_reload(j->unit);
 358                         else
 359                                 r = unit_start(j->unit);
 360                         break;
 361
 362                 case JOB_RESTART: {
 363                         UnitActiveState t = unit_active_state(j->unit);
 364                         if (t == UNIT_INACTIVE || t == UNIT_ACTIVATING) {
 365                                 j->type = JOB_START;
 366                                 r = unit_start(j->unit);
 367                         } else
 368                                 r = unit_stop(j->unit);
 369                         break;
 370                 }
 371
 372                 case JOB_TRY_RESTART: {
 373                         UnitActiveState t = unit_active_state(j->unit);
 374                         if (t == UNIT_INACTIVE || t == UNIT_DEACTIVATING)
 375                                 r = -ENOEXEC;
 376                         else if (t == UNIT_ACTIVATING) {
 377                                 j->type = JOB_START;
 378                                 r = unit_start(j->unit);
 379                         } else
 380                                 r = unit_stop(j->unit);
 381                         break;
 382                 }
 383
 384                 default:
 385                         assert_not_reached("Unknown job type");
 386         }
 387
 388         if (r == -EALREADY)
 389                 r = job_finish_and_invalidate(j, true);
 390         else if (r == -EAGAIN) {
 391                 j->state = JOB_WAITING;
 392                 return -EAGAIN;
 393         } else if (r < 0)
 394                 r = job_finish_and_invalidate(j, false);
 395
 396         return r;
 397 }
 398
 399 int job_finish_and_invalidate(Job *j, bool success) {
 400         Unit *u;
 401         Unit *other;
 402         UnitType t;
 403         Iterator i;
 404
 405         assert(j);
 406         assert(j->installed);
 407
 408         /* Patch restart jobs so that they become normal start jobs */
 409         if (success && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
 410                 j->state = JOB_RUNNING;
 411                 j->type = JOB_START;
 412                 job_schedule_run(j);
 413                 return 0;
 414         }
 415
 416         u = j->unit;
 417         t = j->type;
 418         job_free(j);
 419
 420         /* Fail depending jobs on failure */
 421         if (!success) {
 422
 423                 if (t == JOB_START ||
 424                     t == JOB_VERIFY_ACTIVE ||
 425                     t == JOB_RELOAD_OR_START) {
 426
 427                         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
 428                                 if (other->meta.job &&
 429                                     (other->meta.type == JOB_START ||
 430                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 431                                      other->meta.type == JOB_RELOAD_OR_START))
 432                                         job_finish_and_invalidate(other->meta.job, false);
 433
 434                         SET_FOREACH(other, u->meta.dependencies[UNIT_SOFT_REQUIRED_BY], i)
 435                                 if (other->meta.job &&
 436                                     !other->meta.job->forced &&
 437                                     (other->meta.type == JOB_START ||
 438                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 439                                      other->meta.type == JOB_RELOAD_OR_START))
 440                                         job_finish_and_invalidate(other->meta.job, false);
 441
 442                 } else if (t == JOB_STOP) {
 443
 444                         SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTS], i)
 445                                 if (other->meta.job &&
 446                                     (t == JOB_START ||
 447                                      t == JOB_VERIFY_ACTIVE ||
 448                                      t == JOB_RELOAD_OR_START))
 449                                         job_finish_and_invalidate(other->meta.job, false);
 450                 }
 451         }
 452
 453         /* Try to start the next jobs that can be started */
 454         SET_FOREACH(other, u->meta.dependencies[UNIT_AFTER], i)
 455                 if (other->meta.job)
 456                         job_schedule_run(other->meta.job);
 457         SET_FOREACH(other, u->meta.dependencies[UNIT_BEFORE], i)
 458                 if (other->meta.job)
 459                         job_schedule_run(other->meta.job);
 460
 461         return 0;
 462 }
 463
 464 void job_schedule_run(Job *j) {
 465         assert(j);
 466         assert(j->installed);
 467
 468         if (j->in_run_queue)
 469                 return;
 470
 471         LIST_PREPEND(Job, run_queue, j->manager->run_queue, j);
 472         j->in_run_queue = true;
 473 }