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 #include "log.h"
   9
  10 Job* job_new(Manager *m, JobType type, Unit *unit) {
  11         Job *j;
  12
  13         assert(m);
  14         assert(type < _JOB_TYPE_MAX);
  15         assert(unit);
  16
  17         if (!(j = new0(Job, 1)))
  18                 return NULL;
  19
  20         j->manager = m;
  21         j->id = m->current_job_id++;
  22         j->type = type;
  23         j->unit = unit;
  24
  25         /* We don't link it here, that's what job_dependency() is for */
  26
  27         return j;
  28 }
  29
  30 void job_free(Job *j) {
  31         assert(j);
  32
  33         /* Detach from next 'bigger' objects */
  34         if (j->installed) {
  35                 if (j->unit->meta.job == j)
  36                         j->unit->meta.job = NULL;
  37
  38                 hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
  39                 j->installed = false;
  40         }
  41
  42         /* Detach from next 'smaller' objects */
  43         manager_transaction_unlink_job(j->manager, j);
  44
  45         free(j);
  46 }
  47
  48 JobDependency* job_dependency_new(Job *subject, Job *object, bool matters) {
  49         JobDependency *l;
  50
  51         assert(object);
  52
  53         /* Adds a new job link, which encodes that the 'subject' job
  54          * needs the 'object' job in some way. If 'subject' is NULL
  55          * this means the 'anchor' job (i.e. the one the user
  56          * explcitily asked for) is the requester. */
  57
  58         if (!(l = new0(JobDependency, 1)))
  59                 return NULL;
  60
  61         l->subject = subject;
  62         l->object = object;
  63         l->matters = matters;
  64
  65         if (subject)
  66                 LIST_PREPEND(JobDependency, subject, subject->subject_list, l);
  67         else
  68                 LIST_PREPEND(JobDependency, subject, object->manager->transaction_anchor, l);
  69
  70         LIST_PREPEND(JobDependency, object, object->object_list, l);
  71
  72         return l;
  73 }
  74
  75 void job_dependency_free(JobDependency *l) {
  76         assert(l);
  77
  78         if (l->subject)
  79                 LIST_REMOVE(JobDependency, subject, l->subject->subject_list, l);
  80         else
  81                 LIST_REMOVE(JobDependency, subject, l->object->manager->transaction_anchor, l);
  82
  83         LIST_REMOVE(JobDependency, object, l->object->object_list, l);
  84
  85         free(l);
  86 }
  87
  88 void job_dependency_delete(Job *subject, Job *object, bool *matters) {
  89         JobDependency *l;
  90
  91         assert(object);
  92
  93         LIST_FOREACH(object, l, object->object_list) {
  94                 assert(l->object == object);
  95
  96                 if (l->subject == subject)
  97                         break;
  98         }
  99
 100         if (!l) {
 101                 if (matters)
 102                         *matters = false;
 103                 return;
 104         }
 105
 106         if (matters)
 107                 *matters = l->matters;
 108
 109         job_dependency_free(l);
 110 }
 111
 112 const char* job_type_to_string(JobType t) {
 113
 114         static const char* const job_type_table[_JOB_TYPE_MAX] = {
 115                 [JOB_START] = "start",
 116                 [JOB_VERIFY_ACTIVE] = "verify-active",
 117                 [JOB_STOP] = "stop",
 118                 [JOB_RELOAD] = "reload",
 119                 [JOB_RELOAD_OR_START] = "reload-or-start",
 120                 [JOB_RESTART] = "restart",
 121                 [JOB_TRY_RESTART] = "try-restart",
 122         };
 123
 124         if (t < 0 || t >= _JOB_TYPE_MAX)
 125                 return "n/a";
 126
 127         return job_type_table[t];
 128 }
 129
 130 void job_dump(Job *j, FILE*f, const char *prefix) {
 131
 132         static const char* const job_state_table[_JOB_STATE_MAX] = {
 133                 [JOB_WAITING] = "waiting",
 134                 [JOB_RUNNING] = "running"
 135         };
 136
 137         assert(j);
 138         assert(f);
 139
 140         fprintf(f,
 141                 "%s→ Job %u:\n"
 142                 "%s\tAction: %s → %s\n"
 143                 "%s\tState: %s\n"
 144                 "%s\tForced: %s\n",
 145                 prefix, j->id,
 146                 prefix, unit_id(j->unit), job_type_to_string(j->type),
 147                 prefix, job_state_table[j->state],
 148                 prefix, yes_no(j->forced));
 149 }
 150
 151 bool job_is_anchor(Job *j) {
 152         JobDependency *l;
 153
 154         assert(j);
 155
 156         LIST_FOREACH(object, l, j->object_list)
 157                 if (!l->subject)
 158                         return true;
 159
 160         return false;
 161 }
 162
 163 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
 164         return
 165                 (a == c && b == d) ||
 166                 (a == d && b == c);
 167 }
 168
 169 int job_type_merge(JobType *a, JobType b) {
 170         if (*a == b)
 171                 return 0;
 172
 173         /* Merging is associative! a merged with b merged with c is
 174          * the same as a merged with c merged with b. */
 175
 176         /* Mergeability is transitive! if a can be merged with b and b
 177          * with c then a also with c */
 178
 179         /* Also, if a merged with b cannot be merged with c, then
 180          * either a or b cannot be merged with c either */
 181
 182         if (types_match(*a, b, JOB_START, JOB_VERIFY_ACTIVE))
 183                 *a = JOB_START;
 184         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
 185                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
 186                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD_OR_START) ||
 187                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
 188                 *a = JOB_RELOAD_OR_START;
 189         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
 190                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
 191                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RESTART) ||
 192                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
 193                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
 194                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
 195                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
 196                 *a = JOB_RESTART;
 197         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD))
 198                 *a = JOB_RELOAD;
 199         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_TRY_RESTART) ||
 200                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
 201                 *a = JOB_TRY_RESTART;
 202         else
 203                 return -EEXIST;
 204
 205         return 0;
 206 }
 207
 208 bool job_type_is_mergeable(JobType a, JobType b) {
 209         return job_type_merge(&a, b) >= 0;
 210 }
 211
 212 bool job_type_is_superset(JobType a, JobType b) {
 213
 214         /* Checks whether operation a is a "superset" of b in its
 215          * actions */
 216
 217         if (a == b)
 218                 return true;
 219
 220         switch (a) {
 221                 case JOB_START:
 222                         return b == JOB_VERIFY_ACTIVE;
 223
 224                 case JOB_RELOAD:
 225                         return
 226                                 b == JOB_VERIFY_ACTIVE;
 227
 228                 case JOB_RELOAD_OR_START:
 229                         return
 230                                 b == JOB_RELOAD ||
 231                                 b == JOB_START ||
 232                                 b == JOB_VERIFY_ACTIVE;
 233
 234                 case JOB_RESTART:
 235                         return
 236                                 b == JOB_START ||
 237                                 b == JOB_VERIFY_ACTIVE ||
 238                                 b == JOB_RELOAD ||
 239                                 b == JOB_RELOAD_OR_START ||
 240                                 b == JOB_TRY_RESTART;
 241
 242                 case JOB_TRY_RESTART:
 243                         return
 244                                 b == JOB_VERIFY_ACTIVE ||
 245                                 b == JOB_RELOAD;
 246                 default:
 247                         return false;
 248
 249         }
 250 }
 251
 252 bool job_type_is_conflicting(JobType a, JobType b) {
 253         assert(a >= 0 && a < _JOB_TYPE_MAX);
 254         assert(b >= 0 && b < _JOB_TYPE_MAX);
 255
 256         return (a == JOB_STOP) != (b == JOB_STOP);
 257 }
 258
 259 bool job_is_runnable(Job *j) {
 260         Iterator i;
 261         Unit *other;
 262
 263         assert(j);
 264         assert(j->installed);
 265
 266         /* Checks whether there is any job running for the units this
 267          * job needs to be running after (in the case of a 'positive'
 268          * job type) or before (in the case of a 'negative' job type
 269          * . */
 270
 271         if (j->type == JOB_START ||
 272             j->type == JOB_VERIFY_ACTIVE ||
 273             j->type == JOB_RELOAD ||
 274             j->type == JOB_RELOAD_OR_START) {
 275
 276                 /* Immediate result is that the job is or might be
 277                  * started. In this case lets wait for the
 278                  * dependencies, regardless whether they are
 279                  * starting or stopping something. */
 280
 281                 SET_FOREACH(other, j->unit->meta.dependencies[UNIT_AFTER], i)
 282                         if (other->meta.job)
 283                                 return false;
 284         }
 285
 286         /* Also, if something else is being stopped and we should
 287          * change state after it, then lets wait. */
 288
 289         SET_FOREACH(other, j->unit->meta.dependencies[UNIT_BEFORE], i)
 290                 if (other->meta.job &&
 291                     (other->meta.job->type == JOB_STOP ||
 292                      other->meta.job->type == JOB_RESTART ||
 293                      other->meta.job->type == JOB_TRY_RESTART))
 294                         return false;
 295
 296         /* This means that for a service a and a service b where b
 297          * shall be started after a:
 298          *
 299          *  start a + start b → 1st step start a, 2nd step start b
 300          *  start a + stop b  → 1st step stop b,  2nd step start a
 301          *  stop a  + start b → 1st step stop a,  2nd step start b
 302          *  stop a  + stop b  → 1st step stop b,  2nd step stop a
 303          *
 304          *  This has the side effect that restarts are properly
 305          *  synchronized too. */
 306
 307         return true;
 308 }
 309
 310 int job_run_and_invalidate(Job *j) {
 311         int r;
 312
 313         assert(j);
 314         assert(j->installed);
 315
 316         if (j->in_run_queue) {
 317                 LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
 318                 j->in_run_queue = false;
 319         }
 320
 321         if (j->state != JOB_WAITING)
 322                 return 0;
 323
 324         if (!job_is_runnable(j))
 325                 return -EAGAIN;
 326
 327         j->state = JOB_RUNNING;
 328
 329         switch (j->type) {
 330
 331                 case JOB_START:
 332                         r = unit_start(j->unit);
 333                         if (r == -EBADR)
 334                                 r = 0;
 335                         break;
 336
 337                 case JOB_VERIFY_ACTIVE: {
 338                         UnitActiveState t = unit_active_state(j->unit);
 339                         if (UNIT_IS_ACTIVE_OR_RELOADING(t))
 340                                 r = -EALREADY;
 341                         else if (t == UNIT_ACTIVATING)
 342                                 r = -EAGAIN;
 343                         else
 344                                 r = -ENOEXEC;
 345                         break;
 346                 }
 347
 348                 case JOB_STOP:
 349                         r = unit_stop(j->unit);
 350                         break;
 351
 352                 case JOB_RELOAD:
 353                         r = unit_reload(j->unit);
 354                         break;
 355
 356                 case JOB_RELOAD_OR_START:
 357                         if (unit_active_state(j->unit) == UNIT_ACTIVE)
 358                                 r = unit_reload(j->unit);
 359                         else
 360                                 r = unit_start(j->unit);
 361                         break;
 362
 363                 case JOB_RESTART: {
 364                         UnitActiveState t = unit_active_state(j->unit);
 365                         if (t == UNIT_INACTIVE || t == UNIT_ACTIVATING) {
 366                                 j->type = JOB_START;
 367                                 r = unit_start(j->unit);
 368                         } else
 369                                 r = unit_stop(j->unit);
 370                         break;
 371                 }
 372
 373                 case JOB_TRY_RESTART: {
 374                         UnitActiveState t = unit_active_state(j->unit);
 375                         if (t == UNIT_INACTIVE || t == UNIT_DEACTIVATING)
 376                                 r = -ENOEXEC;
 377                         else if (t == UNIT_ACTIVATING) {
 378                                 j->type = JOB_START;
 379                                 r = unit_start(j->unit);
 380                         } else
 381                                 r = unit_stop(j->unit);
 382                         break;
 383                 }
 384
 385                 default:
 386                         assert_not_reached("Unknown job type");
 387         }
 388
 389         if (r == -EALREADY)
 390                 r = job_finish_and_invalidate(j, true);
 391         else if (r == -EAGAIN) {
 392                 j->state = JOB_WAITING;
 393                 return -EAGAIN;
 394         } else if (r < 0)
 395                 r = job_finish_and_invalidate(j, false);
 396
 397         return r;
 398 }
 399
 400 int job_finish_and_invalidate(Job *j, bool success) {
 401         Unit *u;
 402         Unit *other;
 403         UnitType t;
 404         Iterator i;
 405
 406         assert(j);
 407         assert(j->installed);
 408
 409         log_debug("Job %s/%s finished, success=%s", unit_id(j->unit), job_type_to_string(j->type), yes_no(success));
 410
 411         /* Patch restart jobs so that they become normal start jobs */
 412         if (success && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
 413
 414                 log_debug("Converting job %s/%s → %s/%s",
 415                           unit_id(j->unit), job_type_to_string(j->type),
 416                           unit_id(j->unit), job_type_to_string(JOB_START));
 417
 418                 j->state = JOB_RUNNING;
 419                 j->type = JOB_START;
 420
 421                 job_schedule_run(j);
 422                 return 0;
 423         }
 424
 425         u = j->unit;
 426         t = j->type;
 427         job_free(j);
 428
 429         /* Fail depending jobs on failure */
 430         if (!success) {
 431
 432                 if (t == JOB_START ||
 433                     t == JOB_VERIFY_ACTIVE ||
 434                     t == JOB_RELOAD_OR_START) {
 435
 436                         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
 437                                 if (other->meta.job &&
 438                                     (other->meta.type == JOB_START ||
 439                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 440                                      other->meta.type == JOB_RELOAD_OR_START))
 441                                         job_finish_and_invalidate(other->meta.job, false);
 442
 443                         SET_FOREACH(other, u->meta.dependencies[UNIT_SOFT_REQUIRED_BY], i)
 444                                 if (other->meta.job &&
 445                                     !other->meta.job->forced &&
 446                                     (other->meta.type == JOB_START ||
 447                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 448                                      other->meta.type == JOB_RELOAD_OR_START))
 449                                         job_finish_and_invalidate(other->meta.job, false);
 450
 451                 } else if (t == JOB_STOP) {
 452
 453                         SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTS], i)
 454                                 if (other->meta.job &&
 455                                     (t == JOB_START ||
 456                                      t == JOB_VERIFY_ACTIVE ||
 457                                      t == JOB_RELOAD_OR_START))
 458                                         job_finish_and_invalidate(other->meta.job, false);
 459                 }
 460         }
 461
 462         /* Try to start the next jobs that can be started */
 463         SET_FOREACH(other, u->meta.dependencies[UNIT_AFTER], i)
 464                 if (other->meta.job)
 465                         job_schedule_run(other->meta.job);
 466         SET_FOREACH(other, u->meta.dependencies[UNIT_BEFORE], i)
 467                 if (other->meta.job)
 468                         job_schedule_run(other->meta.job);
 469
 470         return 0;
 471 }
 472
 473 void job_schedule_run(Job *j) {
 474         assert(j);
 475         assert(j->installed);
 476
 477         if (j->in_run_queue)
 478                 return;
 479
 480         LIST_PREPEND(Job, run_queue, j->manager->run_queue, j);
 481         j->in_run_queue = true;
 482 }