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, Name *name) {
  10         Job *j;
  11
  12         assert(m);
  13         assert(type < _JOB_TYPE_MAX);
  14         assert(name);
  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->name = name;
  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->linked) {
  34                 if (j->name->meta.job == j)
  35                         j->name->meta.job = NULL;
  36
  37                 hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
  38                 j->linked = 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                 l->subject_next = subject->subject_list;
  66                 subject->subject_list = l;
  67         } else {
  68                 l->subject_next = object->manager->transaction_anchor;
  69                 object->manager->transaction_anchor = l;
  70         }
  71
  72         if (l->subject_next)
  73                 l->subject_next->subject_prev = l;
  74         l->subject_prev = NULL;
  75
  76         if ((l->object_next = object->object_list))
  77                 l->object_next->object_prev = l;
  78         l->object_prev = NULL;
  79         object->object_list = l;
  80
  81         return l;
  82 }
  83
  84 void job_dependency_free(JobDependency *l) {
  85         assert(l);
  86
  87         if (l->subject_prev)
  88                 l->subject_prev->subject_next = l->subject_next;
  89         else if (l->subject)
  90                 l->subject->subject_list = l->subject_next;
  91         else
  92                 l->object->manager->transaction_anchor = l->subject_next;
  93
  94         if (l->subject_next)
  95                 l->subject_next->subject_prev = l->subject_prev;
  96
  97         if (l->object_prev)
  98                 l->object_prev->object_next = l->object_next;
  99         else
 100                 l->object->object_list = l->object_next;
 101
 102         if (l->object_next)
 103                 l->object_next->object_prev = l->object_prev;
 104
 105         free(l);
 106 }
 107
 108 void job_dependency_delete(Job *subject, Job *object, bool *matters) {
 109         JobDependency *l;
 110
 111         assert(object);
 112
 113         for (l = object->object_list; l; l = l->object_next) {
 114                 assert(l->object == object);
 115
 116                 if (l->subject == subject)
 117                         break;
 118         }
 119
 120         if (!l) {
 121                 if (matters)
 122                         *matters = false;
 123                 return;
 124         }
 125
 126         if (matters)
 127                 *matters = l->matters;
 128
 129         job_dependency_free(l);
 130 }
 131
 132 const char* job_type_to_string(JobType t) {
 133
 134         static const char* const job_type_table[_JOB_TYPE_MAX] = {
 135                 [JOB_START] = "start",
 136                 [JOB_VERIFY_ACTIVE] = "verify-active",
 137                 [JOB_STOP] = "stop",
 138                 [JOB_RELOAD] = "reload",
 139                 [JOB_RELOAD_OR_START] = "reload-or-start",
 140                 [JOB_RESTART] = "restart",
 141                 [JOB_TRY_RESTART] = "try-restart",
 142         };
 143
 144         if (t < 0 || t >= _JOB_TYPE_MAX)
 145                 return "n/a";
 146
 147         return job_type_table[t];
 148 }
 149
 150 void job_dump(Job *j, FILE*f, const char *prefix) {
 151
 152         static const char* const job_state_table[_JOB_STATE_MAX] = {
 153                 [JOB_WAITING] = "waiting",
 154                 [JOB_RUNNING] = "running"
 155         };
 156
 157         assert(j);
 158         assert(f);
 159
 160         fprintf(f,
 161                 "%sJob %u:\n"
 162                 "%s\tAction: %s → %s\n"
 163                 "%s\tState: %s\n"
 164                 "%s\tForced: %s\n",
 165                 prefix, j->id,
 166                 prefix, name_id(j->name), job_type_to_string(j->type),
 167                 prefix, job_state_table[j->state],
 168                 prefix, yes_no(j->forced));
 169 }
 170
 171 bool job_is_anchor(Job *j) {
 172         JobDependency *l;
 173
 174         assert(j);
 175
 176         for (l = j->object_list; l; l = l->object_next)
 177                 if (!l->subject)
 178                         return true;
 179
 180         return false;
 181 }
 182
 183 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
 184         return
 185                 (a == c && b == d) ||
 186                 (a == d && b == c);
 187 }
 188
 189 int job_type_merge(JobType *a, JobType b) {
 190         if (*a == b)
 191                 return 0;
 192
 193         /* Merging is associative! a merged with b merged with c is
 194          * the same as a merged with c merged with b. */
 195
 196         /* Mergeability is transitive! if a can be merged with b and b
 197          * with c then a also with c */
 198
 199         /* Also, if a merged with b cannot be merged with c, then
 200          * either a or b cannot be merged with c either */
 201
 202         if (types_match(*a, b, JOB_START, JOB_VERIFY_ACTIVE))
 203                 *a = JOB_START;
 204         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
 205                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
 206                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD_OR_START) ||
 207                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
 208                 *a = JOB_RELOAD_OR_START;
 209         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
 210                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
 211                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RESTART) ||
 212                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
 213                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
 214                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
 215                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
 216                 *a = JOB_RESTART;
 217         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD))
 218                 *a = JOB_RELOAD;
 219         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_TRY_RESTART) ||
 220                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
 221                 *a = JOB_TRY_RESTART;
 222         else
 223                 return -EEXIST;
 224
 225         return 0;
 226 }
 227
 228 bool job_type_is_mergeable(JobType a, JobType b) {
 229         return job_type_merge(&a, b) >= 0;
 230 }
 231
 232 bool job_type_is_superset(JobType a, JobType b) {
 233
 234         /* Checks whether operation a is a "superset" of b in its
 235          * actions */
 236
 237         if (a == b)
 238                 return true;
 239
 240         switch (a) {
 241                 case JOB_START:
 242                         return b == JOB_VERIFY_ACTIVE;
 243
 244                 case JOB_RELOAD:
 245                         return
 246                                 b == JOB_VERIFY_ACTIVE;
 247
 248                 case JOB_RELOAD_OR_START:
 249                         return
 250                                 b == JOB_RELOAD ||
 251                                 b == JOB_START ||
 252                                 b == JOB_VERIFY_ACTIVE;
 253
 254                 case JOB_RESTART:
 255                         return
 256                                 b == JOB_START ||
 257                                 b == JOB_VERIFY_ACTIVE ||
 258                                 b == JOB_RELOAD ||
 259                                 b == JOB_RELOAD_OR_START ||
 260                                 b == JOB_TRY_RESTART;
 261
 262                 case JOB_TRY_RESTART:
 263                         return
 264                                 b == JOB_VERIFY_ACTIVE ||
 265                                 b == JOB_RELOAD;
 266                 default:
 267                         return false;
 268
 269         }
 270 }
 271
 272 bool job_type_is_conflicting(JobType a, JobType b) {
 273         assert(a >= 0 && a < _JOB_TYPE_MAX);
 274         assert(b >= 0 && b < _JOB_TYPE_MAX);
 275
 276         return (a == JOB_STOP) != (b == JOB_STOP);
 277 }
 278
 279 bool job_is_runnable(Job *j) {
 280         Iterator i;
 281         Name *other;
 282
 283         assert(j);
 284         assert(j->linked);
 285
 286         /* Checks whether there is any job running for the names this
 287          * job needs to be running after (in the case of a 'positive'
 288          * job type) or before (in the case of a 'negative' job type
 289          * . */
 290
 291         if (j->type == JOB_START ||
 292             j->type == JOB_VERIFY_ACTIVE ||
 293             j->type == JOB_RELOAD ||
 294             j->type == JOB_RELOAD_OR_START) {
 295
 296                 /* Immediate result is that the job is or might be
 297                  * started. In this case lets wait for the
 298                  * dependencies, regardless whether they are
 299                  * starting or stopping something. */
 300
 301                 SET_FOREACH(other, j->name->meta.dependencies[NAME_AFTER], i)
 302                         if (other->meta.job)
 303                                 return false;
 304         }
 305
 306         /* Also, if something else is being stopped and we should
 307          * change state after it, then lets wait. */
 308
 309         SET_FOREACH(other, j->name->meta.dependencies[NAME_BEFORE], i)
 310                 if (other->meta.job &&
 311                     (other->meta.job->type == JOB_STOP ||
 312                      other->meta.job->type == JOB_RESTART ||
 313                      other->meta.job->type == JOB_TRY_RESTART))
 314                         return false;
 315
 316         /* This means that for a service a and a service b where b
 317          * shall be started after a:
 318          *
 319          *  start a + start b → 1st step start a, 2nd step start b
 320          *  start a + stop b  → 1st step stop b,  2nd step start a
 321          *  stop a  + start b → 1st step stop a,  2nd step start b
 322          *  stop a  + stop b  → 1st step stop b,  2nd step stop a
 323          *
 324          *  This has the side effect that restarts are properly
 325          *  synchronized too. */
 326
 327         return true;
 328 }
 329
 330 int job_run_and_invalidate(Job *j) {
 331         int r;
 332         assert(j);
 333
 334         if (j->in_run_queue) {
 335                 LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
 336                 j->in_run_queue = false;
 337         }
 338
 339         if (j->state != JOB_WAITING)
 340                 return 0;
 341
 342         if (!job_is_runnable(j))
 343                 return -EAGAIN;
 344
 345         j->state = JOB_RUNNING;
 346
 347         switch (j->type) {
 348
 349                 case JOB_START:
 350                         r = name_start(j->name);
 351                         if (r == -EBADR)
 352                                 r = 0;
 353                         break;
 354
 355                 case JOB_VERIFY_ACTIVE: {
 356                         NameActiveState t = name_active_state(j->name);
 357                         if (NAME_IS_ACTIVE_OR_RELOADING(t))
 358                                 r = -EALREADY;
 359                         else if (t == NAME_ACTIVATING)
 360                                 r = -EAGAIN;
 361                         else
 362                                 r = -ENOEXEC;
 363                         break;
 364                 }
 365
 366                 case JOB_STOP:
 367                         r = name_stop(j->name);
 368                         break;
 369
 370                 case JOB_RELOAD:
 371                         r = name_reload(j->name);
 372                         break;
 373
 374                 case JOB_RELOAD_OR_START:
 375                         if (name_active_state(j->name) == NAME_ACTIVE)
 376                                 r = name_reload(j->name);
 377                         else
 378                                 r = name_start(j->name);
 379                         break;
 380
 381                 case JOB_RESTART: {
 382                         NameActiveState t = name_active_state(j->name);
 383                         if (t == NAME_INACTIVE || t == NAME_ACTIVATING) {
 384                                 j->type = JOB_START;
 385                                 r = name_start(j->name);
 386                         } else
 387                                 r = name_stop(j->name);
 388                         break;
 389                 }
 390
 391                 case JOB_TRY_RESTART: {
 392                         NameActiveState t = name_active_state(j->name);
 393                         if (t == NAME_INACTIVE || t == NAME_DEACTIVATING)
 394                                 r = -ENOEXEC;
 395                         else if (t == NAME_ACTIVATING) {
 396                                 j->type = JOB_START;
 397                                 r = name_start(j->name);
 398                         } else
 399                                 r = name_stop(j->name);
 400                         break;
 401                 }
 402
 403                 default:
 404                         ;
 405         }
 406
 407         if (r == -EALREADY)
 408                 r = job_finish_and_invalidate(j, true);
 409         else if (r == -EAGAIN) {
 410                 j->state = JOB_WAITING;
 411                 return -EAGAIN;
 412         } else if (r < 0)
 413                 r = job_finish_and_invalidate(j, false);
 414
 415         return r;
 416 }
 417
 418 int job_finish_and_invalidate(Job *j, bool success) {
 419         Name *n;
 420         Name *other;
 421         NameType t;
 422         Iterator i;
 423
 424         assert(j);
 425
 426         /* Patch restart jobs so that they become normal start jobs */
 427         if (success && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
 428                 j->state = JOB_RUNNING;
 429                 j->type = JOB_START;
 430                 job_schedule_run(j);
 431                 return 0;
 432         }
 433
 434         n = j->name;
 435         t = j->type;
 436         job_free(j);
 437
 438         /* Fail depending jobs on failure */
 439         if (!success) {
 440
 441                 if (t == JOB_START ||
 442                     t == JOB_VERIFY_ACTIVE ||
 443                     t == JOB_RELOAD_OR_START) {
 444
 445                         SET_FOREACH(other, n->meta.dependencies[NAME_REQUIRED_BY], i)
 446                                 if (other->meta.job &&
 447                                     (other->meta.type == JOB_START ||
 448                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 449                                      other->meta.type == JOB_RELOAD_OR_START))
 450                                         job_finish_and_invalidate(other->meta.job, false);
 451
 452                         SET_FOREACH(other, n->meta.dependencies[NAME_SOFT_REQUIRED_BY], i)
 453                                 if (other->meta.job &&
 454                                     !other->meta.job->forced &&
 455                                     (other->meta.type == JOB_START ||
 456                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 457                                      other->meta.type == JOB_RELOAD_OR_START))
 458                                         job_finish_and_invalidate(other->meta.job, false);
 459
 460                 } else if (t == JOB_STOP) {
 461
 462                         SET_FOREACH(other, n->meta.dependencies[NAME_CONFLICTS], i)
 463                                 if (other->meta.job &&
 464                                     (t == JOB_START ||
 465                                      t == JOB_VERIFY_ACTIVE ||
 466                                      t == JOB_RELOAD_OR_START))
 467                                         job_finish_and_invalidate(other->meta.job, false);
 468                 }
 469         }
 470
 471         /* Try to start the next jobs that can be started */
 472         SET_FOREACH(other, n->meta.dependencies[NAME_AFTER], i)
 473                 if (other->meta.job)
 474                         job_schedule_run(other->meta.job);
 475         SET_FOREACH(other, n->meta.dependencies[NAME_BEFORE], i)
 476                 if (other->meta.job)
 477                         job_schedule_run(other->meta.job);
 478
 479         return 0;
 480 }
 481
 482 void job_schedule_run(Job *j) {
 483         assert(j);
 484         assert(j->linked);
 485
 486         if (j->in_run_queue)
 487                 return;
 488
 489         LIST_PREPEND(Job, run_queue, j->manager->run_queue, j);
 490         j->in_run_queue = true;
 491 }