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_type_is_applicable(JobType j, NameType n) {
 280         assert(j >= 0 && j < _JOB_TYPE_MAX);
 281         assert(n >= 0 && n < _NAME_TYPE_MAX);
 282
 283         switch (j) {
 284                 case JOB_VERIFY_ACTIVE:
 285                 case JOB_START:
 286                         return true;
 287
 288                 case JOB_STOP:
 289                 case JOB_RESTART:
 290                 case JOB_TRY_RESTART:
 291                         return name_type_can_start(n);
 292
 293                 case JOB_RELOAD:
 294                         return name_type_can_reload(n);
 295
 296                 case JOB_RELOAD_OR_START:
 297                         return name_type_can_reload(n) && name_type_can_start(n);
 298
 299                 default:
 300                         assert_not_reached("Invalid job type");
 301         }
 302 }
 303
 304 bool job_is_runnable(Job *j) {
 305         void *state;
 306         Name *other;
 307
 308         assert(j);
 309         assert(j->linked);
 310
 311         /* Checks whether there is any job running for the names this
 312          * job needs to be running after (in the case of a 'positive'
 313          * job type) or before (in the case of a 'negative' job type
 314          * . */
 315
 316         if (j->type == JOB_START ||
 317             j->type == JOB_VERIFY_ACTIVE ||
 318             j->type == JOB_RELOAD ||
 319             j->type == JOB_RELOAD_OR_START) {
 320
 321                 /* Immediate result is that the job is or might be
 322                  * started. In this case lets wait for the
 323                  * dependencies, regardless whether they are
 324                  * starting or stopping something. */
 325
 326                 SET_FOREACH(other, j->name->meta.dependencies[NAME_AFTER], state)
 327                         if (other->meta.job)
 328                                 return false;
 329         }
 330
 331         /* Also, if something else is being stopped and we should
 332          * change state after it, then lets wait. */
 333
 334         SET_FOREACH(other, j->name->meta.dependencies[NAME_BEFORE], state)
 335                 if (other->meta.job &&
 336                     (other->meta.job->type == JOB_STOP ||
 337                      other->meta.job->type == JOB_RESTART ||
 338                      other->meta.job->type == JOB_TRY_RESTART))
 339                         return false;
 340
 341         /* This means that for a service a and a service b where b
 342          * shall be started after a:
 343          *
 344          *  start a + start b → 1st step start a, 2nd step start b
 345          *  start a + stop b  → 1st step stop b,  2nd step start a
 346          *  stop a  + start b → 1st step stop a,  2nd step start b
 347          *  stop a  + stop b  → 1st step stop b,  2nd step stop a
 348          *
 349          *  This has the side effect that restarts are properly
 350          *  synchronized too. */
 351
 352         return true;
 353 }
 354
 355 int job_run_and_invalidate(Job *j) {
 356         int r;
 357         assert(j);
 358
 359         if (!job_is_runnable(j))
 360                 return -EAGAIN;
 361
 362         if (j->state != JOB_WAITING)
 363                 return 0;
 364
 365         switch (j->type) {
 366
 367                 case JOB_START:
 368                         r = name_start(j->name);
 369                         if (r == -EBADR)
 370                                 r = 0;
 371                         break;
 372
 373                 case JOB_VERIFY_ACTIVE: {
 374                         NameActiveState t = name_active_state(j->name);
 375                         if (NAME_IS_ACTIVE_OR_RELOADING(t))
 376                                 r = -EALREADY;
 377                         else if (t == NAME_ACTIVATING)
 378                                 r = -EAGAIN;
 379                         else
 380                                 r = -ENOEXEC;
 381                         break;
 382                 }
 383
 384                 case JOB_STOP:
 385                         r = name_stop(j->name);
 386                         break;
 387
 388                 case JOB_RELOAD:
 389                         r = name_reload(j->name);
 390                         break;
 391
 392                 case JOB_RELOAD_OR_START:
 393                         if (name_active_state(j->name) == NAME_ACTIVE)
 394                                 r = name_reload(j->name);
 395                         else
 396                                 r = name_start(j->name);
 397                         break;
 398
 399                 case JOB_RESTART: {
 400                         NameActiveState t = name_active_state(j->name);
 401                         if (t == NAME_INACTIVE || t == NAME_ACTIVATING) {
 402                                 j->type = JOB_START;
 403                                 r = name_start(j->name);
 404                         } else
 405                                 r = name_stop(j->name);
 406                         break;
 407                 }
 408
 409                 case JOB_TRY_RESTART: {
 410                         NameActiveState t = name_active_state(j->name);
 411                         if (t == NAME_INACTIVE || t == NAME_DEACTIVATING)
 412                                 r = -ENOEXEC;
 413                         else if (t == NAME_ACTIVATING) {
 414                                 j->type = JOB_START;
 415                                 r = name_start(j->name);
 416                         } else
 417                                 r = name_stop(j->name);
 418                         break;
 419                 }
 420
 421                 default:
 422                         ;
 423         }
 424
 425         if (r >= 0)
 426                 j->state = JOB_RUNNING;
 427         else if (r == -EALREADY)
 428                 r = job_finish_and_invalidate(j, true);
 429         else if (r != -EAGAIN)
 430                 r = job_finish_and_invalidate(j, false);
 431
 432         return r;
 433 }
 434
 435 int job_finish_and_invalidate(Job *j, bool success) {
 436         Name *n;
 437         void *state;
 438         Name *other;
 439         NameType t;
 440
 441         assert(j);
 442
 443         if (success && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
 444                 j->state = JOB_RUNNING;
 445                 j->type = JOB_START;
 446                 return job_run_and_invalidate(j);
 447         }
 448
 449         n = j->name;
 450         t = j->type;
 451         job_free(j);
 452
 453         /* Fail depending jobs on failure */
 454         if (!success) {
 455
 456                 if (t == JOB_START ||
 457                     t == JOB_VERIFY_ACTIVE ||
 458                     t == JOB_RELOAD_OR_START) {
 459
 460                         SET_FOREACH(other, n->meta.dependencies[NAME_REQUIRED_BY], state)
 461                                 if (other->meta.job &&
 462                                     (other->meta.type == JOB_START ||
 463                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 464                                      other->meta.type == JOB_RELOAD_OR_START))
 465                                         job_finish_and_invalidate(other->meta.job, false);
 466
 467                         SET_FOREACH(other, n->meta.dependencies[NAME_SOFT_REQUIRED_BY], state)
 468                                 if (other->meta.job &&
 469                                     !other->meta.job->forced &&
 470                                     (other->meta.type == JOB_START ||
 471                                      other->meta.type == JOB_VERIFY_ACTIVE ||
 472                                      other->meta.type == JOB_RELOAD_OR_START))
 473                                         job_finish_and_invalidate(other->meta.job, false);
 474
 475                 } else if (t == JOB_STOP) {
 476
 477                         SET_FOREACH(other, n->meta.dependencies[NAME_CONFLICTS], state)
 478                                 if (other->meta.job &&
 479                                     (t == JOB_START ||
 480                                      t == JOB_VERIFY_ACTIVE ||
 481                                      t == JOB_RELOAD_OR_START))
 482                                         job_finish_and_invalidate(other->meta.job, false);
 483                 }
 484         }
 485
 486         /* Try to start the next jobs that can be started */
 487         SET_FOREACH(other, n->meta.dependencies[NAME_AFTER], state)
 488                 if (other->meta.job)
 489                         job_run_and_invalidate(other->meta.job);
 490         SET_FOREACH(other, n->meta.dependencies[NAME_BEFORE], state)
 491                 if (other->meta.job)
 492                         job_run_and_invalidate(other->meta.job);
 493
 494         return 0;
 495 }