job.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 <assert.h>
  23 #include <errno.h>
  24
  25 #include "set.h"
  26 #include "unit.h"
  27 #include "macro.h"
  28 #include "strv.h"
  29 #include "load-fragment.h"
  30 #include "load-dropin.h"
  31 #include "log.h"
  32 #include "dbus-job.h"
  33
  34 Job* job_new(Manager *m, JobType type, Unit *unit) {
  35         Job *j;
  36
  37         assert(m);
  38         assert(type < _JOB_TYPE_MAX);
  39         assert(unit);
  40
  41         if (!(j = new0(Job, 1)))
  42                 return NULL;
  43
  44         j->manager = m;
  45         j->id = m->current_job_id++;
  46         j->type = type;
  47         j->unit = unit;
  48
  49         /* We don't link it here, that's what job_dependency() is for */
  50
  51         return j;
  52 }
  53
  54 void job_free(Job *j) {
  55         assert(j);
  56
  57         /* Detach from next 'bigger' objects */
  58         if (j->installed) {
  59                 bus_job_send_removed_signal(j);
  60
  61                 if (j->unit->meta.job == j) {
  62                         j->unit->meta.job = NULL;
  63                         unit_add_to_gc_queue(j->unit);
  64                 }
  65
  66                 hashmap_remove(j->manager->jobs, UINT32_TO_PTR(j->id));
  67                 j->installed = false;
  68         }
  69
  70         /* Detach from next 'smaller' objects */
  71         manager_transaction_unlink_job(j->manager, j, true);
  72
  73         if (j->in_run_queue)
  74                 LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
  75
  76         if (j->in_dbus_queue)
  77                 LIST_REMOVE(Job, dbus_queue, j->manager->dbus_job_queue, j);
  78
  79         free(j);
  80 }
  81
  82 JobDependency* job_dependency_new(Job *subject, Job *object, bool matters) {
  83         JobDependency *l;
  84
  85         assert(object);
  86
  87         /* Adds a new job link, which encodes that the 'subject' job
  88          * needs the 'object' job in some way. If 'subject' is NULL
  89          * this means the 'anchor' job (i.e. the one the user
  90          * explcitily asked for) is the requester. */
  91
  92         if (!(l = new0(JobDependency, 1)))
  93                 return NULL;
  94
  95         l->subject = subject;
  96         l->object = object;
  97         l->matters = matters;
  98
  99         if (subject)
 100                 LIST_PREPEND(JobDependency, subject, subject->subject_list, l);
 101         else
 102                 LIST_PREPEND(JobDependency, subject, object->manager->transaction_anchor, l);
 103
 104         LIST_PREPEND(JobDependency, object, object->object_list, l);
 105
 106         return l;
 107 }
 108
 109 void job_dependency_free(JobDependency *l) {
 110         assert(l);
 111
 112         if (l->subject)
 113                 LIST_REMOVE(JobDependency, subject, l->subject->subject_list, l);
 114         else
 115                 LIST_REMOVE(JobDependency, subject, l->object->manager->transaction_anchor, l);
 116
 117         LIST_REMOVE(JobDependency, object, l->object->object_list, l);
 118
 119         free(l);
 120 }
 121
 122 void job_dependency_delete(Job *subject, Job *object, bool *matters) {
 123         JobDependency *l;
 124
 125         assert(object);
 126
 127         LIST_FOREACH(object, l, object->object_list) {
 128                 assert(l->object == object);
 129
 130                 if (l->subject == subject)
 131                         break;
 132         }
 133
 134         if (!l) {
 135                 if (matters)
 136                         *matters = false;
 137                 return;
 138         }
 139
 140         if (matters)
 141                 *matters = l->matters;
 142
 143         job_dependency_free(l);
 144 }
 145
 146 void job_dump(Job *j, FILE*f, const char *prefix) {
 147
 148
 149         assert(j);
 150         assert(f);
 151
 152         fprintf(f,
 153                 "%s→ Job %u:\n"
 154                 "%s\tAction: %s → %s\n"
 155                 "%s\tState: %s\n"
 156                 "%s\tForced: %s\n",
 157                 prefix, j->id,
 158                 prefix, j->unit->meta.id, job_type_to_string(j->type),
 159                 prefix, job_state_to_string(j->state),
 160                 prefix, yes_no(j->override));
 161 }
 162
 163 bool job_is_anchor(Job *j) {
 164         JobDependency *l;
 165
 166         assert(j);
 167
 168         LIST_FOREACH(object, l, j->object_list)
 169                 if (!l->subject)
 170                         return true;
 171
 172         return false;
 173 }
 174
 175 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
 176         return
 177                 (a == c && b == d) ||
 178                 (a == d && b == c);
 179 }
 180
 181 int job_type_merge(JobType *a, JobType b) {
 182         if (*a == b)
 183                 return 0;
 184
 185         /* Merging is associative! a merged with b merged with c is
 186          * the same as a merged with c merged with b. */
 187
 188         /* Mergeability is transitive! if a can be merged with b and b
 189          * with c then a also with c */
 190
 191         /* Also, if a merged with b cannot be merged with c, then
 192          * either a or b cannot be merged with c either */
 193
 194         if (types_match(*a, b, JOB_START, JOB_VERIFY_ACTIVE))
 195                 *a = JOB_START;
 196         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
 197                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
 198                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD_OR_START) ||
 199                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
 200                 *a = JOB_RELOAD_OR_START;
 201         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
 202                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
 203                  types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RESTART) ||
 204                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
 205                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
 206                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
 207                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
 208                 *a = JOB_RESTART;
 209         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_RELOAD))
 210                 *a = JOB_RELOAD;
 211         else if (types_match(*a, b, JOB_VERIFY_ACTIVE, JOB_TRY_RESTART) ||
 212                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
 213                 *a = JOB_TRY_RESTART;
 214         else
 215                 return -EEXIST;
 216
 217         return 0;
 218 }
 219
 220 bool job_type_is_mergeable(JobType a, JobType b) {
 221         return job_type_merge(&a, b) >= 0;
 222 }
 223
 224 bool job_type_is_superset(JobType a, JobType b) {
 225
 226         /* Checks whether operation a is a "superset" of b in its
 227          * actions */
 228
 229         if (a == b)
 230                 return true;
 231
 232         switch (a) {
 233                 case JOB_START:
 234                         return b == JOB_VERIFY_ACTIVE;
 235
 236                 case JOB_RELOAD:
 237                         return
 238                                 b == JOB_VERIFY_ACTIVE;
 239
 240                 case JOB_RELOAD_OR_START:
 241                         return
 242                                 b == JOB_RELOAD ||
 243                                 b == JOB_START ||
 244                                 b == JOB_VERIFY_ACTIVE;
 245
 246                 case JOB_RESTART:
 247                         return
 248                                 b == JOB_START ||
 249                                 b == JOB_VERIFY_ACTIVE ||
 250                                 b == JOB_RELOAD ||
 251                                 b == JOB_RELOAD_OR_START ||
 252                                 b == JOB_TRY_RESTART;
 253
 254                 case JOB_TRY_RESTART:
 255                         return
 256                                 b == JOB_VERIFY_ACTIVE ||
 257                                 b == JOB_RELOAD;
 258                 default:
 259                         return false;
 260
 261         }
 262 }
 263
 264 bool job_type_is_conflicting(JobType a, JobType b) {
 265         assert(a >= 0 && a < _JOB_TYPE_MAX);
 266         assert(b >= 0 && b < _JOB_TYPE_MAX);
 267
 268         return (a == JOB_STOP) != (b == JOB_STOP);
 269 }
 270
 271 bool job_type_is_redundant(JobType a, UnitActiveState b) {
 272         switch (a) {
 273
 274         case JOB_START:
 275                 return
 276                         b == UNIT_ACTIVE ||
 277                         b == UNIT_ACTIVE_RELOADING;
 278
 279         case JOB_STOP:
 280                 return
 281                         b == UNIT_INACTIVE;
 282
 283         case JOB_VERIFY_ACTIVE:
 284                 return
 285                         b == UNIT_ACTIVE ||
 286                         b == UNIT_ACTIVE_RELOADING;
 287
 288         case JOB_RELOAD:
 289                 return
 290                         b == UNIT_ACTIVE_RELOADING;
 291
 292         case JOB_RELOAD_OR_START:
 293                 return
 294                         b == UNIT_ACTIVATING ||
 295                         b == UNIT_ACTIVE_RELOADING;
 296
 297         case JOB_RESTART:
 298                 return
 299                         b == UNIT_ACTIVATING;
 300
 301         case JOB_TRY_RESTART:
 302                 return
 303                         b == UNIT_ACTIVATING;
 304
 305         default:
 306                 assert_not_reached("Invalid job type");
 307         }
 308 }
 309
 310 bool job_is_runnable(Job *j) {
 311         Iterator i;
 312         Unit *other;
 313
 314         assert(j);
 315         assert(j->installed);
 316
 317         /* Checks whether there is any job running for the units this
 318          * job needs to be running after (in the case of a 'positive'
 319          * job type) or before (in the case of a 'negative' job type
 320          * . */
 321
 322         if (j->type == JOB_START ||
 323             j->type == JOB_VERIFY_ACTIVE ||
 324             j->type == JOB_RELOAD ||
 325             j->type == JOB_RELOAD_OR_START) {
 326
 327                 /* Immediate result is that the job is or might be
 328                  * started. In this case lets wait for the
 329                  * dependencies, regardless whether they are
 330                  * starting or stopping something. */
 331
 332                 SET_FOREACH(other, j->unit->meta.dependencies[UNIT_AFTER], i)
 333                         if (other->meta.job)
 334                                 return false;
 335         }
 336
 337         /* Also, if something else is being stopped and we should
 338          * change state after it, then lets wait. */
 339
 340         SET_FOREACH(other, j->unit->meta.dependencies[UNIT_BEFORE], i)
 341                 if (other->meta.job &&
 342                     (other->meta.job->type == JOB_STOP ||
 343                      other->meta.job->type == JOB_RESTART ||
 344                      other->meta.job->type == JOB_TRY_RESTART))
 345                         return false;
 346
 347         /* This means that for a service a and a service b where b
 348          * shall be started after a:
 349          *
 350          *  start a + start b → 1st step start a, 2nd step start b
 351          *  start a + stop b  → 1st step stop b,  2nd step start a
 352          *  stop a  + start b → 1st step stop a,  2nd step start b
 353          *  stop a  + stop b  → 1st step stop b,  2nd step stop a
 354          *
 355          *  This has the side effect that restarts are properly
 356          *  synchronized too. */
 357
 358         return true;
 359 }
 360
 361 int job_run_and_invalidate(Job *j) {
 362         int r;
 363
 364         assert(j);
 365         assert(j->installed);
 366
 367         if (j->in_run_queue) {
 368                 LIST_REMOVE(Job, run_queue, j->manager->run_queue, j);
 369                 j->in_run_queue = false;
 370         }
 371
 372         if (j->state != JOB_WAITING)
 373                 return 0;
 374
 375         if (!job_is_runnable(j))
 376                 return -EAGAIN;
 377
 378         j->state = JOB_RUNNING;
 379         job_add_to_dbus_queue(j);
 380
 381         switch (j->type) {
 382
 383                 case JOB_START:
 384                         r = unit_start(j->unit);
 385                         if (r == -EBADR)
 386                                 r = 0;
 387                         break;
 388
 389                 case JOB_VERIFY_ACTIVE: {
 390                         UnitActiveState t = unit_active_state(j->unit);
 391                         if (UNIT_IS_ACTIVE_OR_RELOADING(t))
 392                                 r = -EALREADY;
 393                         else if (t == UNIT_ACTIVATING)
 394                                 r = -EAGAIN;
 395                         else
 396                                 r = -ENOEXEC;
 397                         break;
 398                 }
 399
 400                 case JOB_STOP:
 401                         r = unit_stop(j->unit);
 402                         break;
 403
 404                 case JOB_RELOAD:
 405                         r = unit_reload(j->unit);
 406                         break;
 407
 408                 case JOB_RELOAD_OR_START:
 409                         if (unit_active_state(j->unit) == UNIT_ACTIVE)
 410                                 r = unit_reload(j->unit);
 411                         else
 412                                 r = unit_start(j->unit);
 413                         break;
 414
 415                 case JOB_RESTART: {
 416                         UnitActiveState t = unit_active_state(j->unit);
 417                         if (t == UNIT_INACTIVE || t == UNIT_ACTIVATING) {
 418                                 j->type = JOB_START;
 419                                 r = unit_start(j->unit);
 420                         } else
 421                                 r = unit_stop(j->unit);
 422                         break;
 423                 }
 424
 425                 case JOB_TRY_RESTART: {
 426                         UnitActiveState t = unit_active_state(j->unit);
 427                         if (t == UNIT_INACTIVE || t == UNIT_DEACTIVATING)
 428                                 r = -ENOEXEC;
 429                         else if (t == UNIT_ACTIVATING) {
 430                                 j->type = JOB_START;
 431                                 r = unit_start(j->unit);
 432                         } else
 433                                 r = unit_stop(j->unit);
 434                         break;
 435                 }
 436
 437                 default:
 438                         assert_not_reached("Unknown job type");
 439         }
 440
 441         if (r == -EALREADY)
 442                 r = job_finish_and_invalidate(j, true);
 443         else if (r == -EAGAIN) {
 444                 j->state = JOB_WAITING;
 445                 return -EAGAIN;
 446         } else if (r < 0)
 447                 r = job_finish_and_invalidate(j, false);
 448
 449         return r;
 450 }
 451
 452 int job_finish_and_invalidate(Job *j, bool success) {
 453         Unit *u;
 454         Unit *other;
 455         JobType t;
 456         Iterator i;
 457
 458         assert(j);
 459         assert(j->installed);
 460
 461         log_debug("Job %s/%s finished, success=%s", j->unit->meta.id, job_type_to_string(j->type), yes_no(success));
 462         job_add_to_dbus_queue(j);
 463
 464         /* Patch restart jobs so that they become normal start jobs */
 465         if (success && (j->type == JOB_RESTART || j->type == JOB_TRY_RESTART)) {
 466
 467                 log_debug("Converting job %s/%s → %s/%s",
 468                           j->unit->meta.id, job_type_to_string(j->type),
 469                           j->unit->meta.id, job_type_to_string(JOB_START));
 470
 471                 j->state = JOB_RUNNING;
 472                 j->type = JOB_START;
 473
 474                 job_add_to_run_queue(j);
 475                 return 0;
 476         }
 477
 478         u = j->unit;
 479         t = j->type;
 480         job_free(j);
 481
 482         /* Fail depending jobs on failure */
 483         if (!success) {
 484
 485                 if (t == JOB_START ||
 486                     t == JOB_VERIFY_ACTIVE ||
 487                     t == JOB_RELOAD_OR_START) {
 488
 489                         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY], i)
 490                                 if (other->meta.job &&
 491                                     (other->meta.job->type == JOB_START ||
 492                                      other->meta.job->type == JOB_VERIFY_ACTIVE ||
 493                                      other->meta.job->type == JOB_RELOAD_OR_START))
 494                                         job_finish_and_invalidate(other->meta.job, false);
 495
 496                         SET_FOREACH(other, u->meta.dependencies[UNIT_REQUIRED_BY_OVERRIDABLE], i)
 497                                 if (other->meta.job &&
 498                                     !other->meta.job->override &&
 499                                     (other->meta.job->type == JOB_START ||
 500                                      other->meta.job->type == JOB_VERIFY_ACTIVE ||
 501                                      other->meta.job->type == JOB_RELOAD_OR_START))
 502                                         job_finish_and_invalidate(other->meta.job, false);
 503
 504                 } else if (t == JOB_STOP) {
 505
 506                         SET_FOREACH(other, u->meta.dependencies[UNIT_CONFLICTS], i)
 507                                 if (other->meta.job &&
 508                                     (other->meta.job->type == JOB_START ||
 509                                      other->meta.job->type == JOB_VERIFY_ACTIVE ||
 510                                      other->meta.job->type == JOB_RELOAD_OR_START))
 511                                         job_finish_and_invalidate(other->meta.job, false);
 512                 }
 513         }
 514
 515         /* Try to start the next jobs that can be started */
 516         SET_FOREACH(other, u->meta.dependencies[UNIT_AFTER], i)
 517                 if (other->meta.job)
 518                         job_add_to_run_queue(other->meta.job);
 519         SET_FOREACH(other, u->meta.dependencies[UNIT_BEFORE], i)
 520                 if (other->meta.job)
 521                         job_add_to_run_queue(other->meta.job);
 522
 523         return 0;
 524 }
 525
 526 void job_add_to_run_queue(Job *j) {
 527         assert(j);
 528         assert(j->installed);
 529
 530         if (j->in_run_queue)
 531                 return;
 532
 533         LIST_PREPEND(Job, run_queue, j->manager->run_queue, j);
 534         j->in_run_queue = true;
 535 }
 536
 537 void job_add_to_dbus_queue(Job *j) {
 538         assert(j);
 539         assert(j->installed);
 540
 541         if (j->in_dbus_queue)
 542                 return;
 543
 544         LIST_PREPEND(Job, dbus_queue, j->manager->dbus_job_queue, j);
 545         j->in_dbus_queue = true;
 546 }
 547
 548 char *job_dbus_path(Job *j) {
 549         char *p;
 550
 551         assert(j);
 552
 553         if (asprintf(&p, "/org/freedesktop/systemd1/job/%lu", (unsigned long) j->id) < 0)
 554                 return NULL;
 555
 556         return p;
 557 }
 558
 559 static const char* const job_state_table[_JOB_STATE_MAX] = {
 560         [JOB_WAITING] = "waiting",
 561         [JOB_RUNNING] = "running"
 562 };
 563
 564 DEFINE_STRING_TABLE_LOOKUP(job_state, JobState);
 565
 566 static const char* const job_type_table[_JOB_TYPE_MAX] = {
 567         [JOB_START] = "start",
 568         [JOB_VERIFY_ACTIVE] = "verify-active",
 569         [JOB_STOP] = "stop",
 570         [JOB_RELOAD] = "reload",
 571         [JOB_RELOAD_OR_START] = "reload-or-start",
 572         [JOB_RESTART] = "restart",
 573         [JOB_TRY_RESTART] = "try-restart",
 574 };
 575
 576 DEFINE_STRING_TABLE_LOOKUP(job_type, JobType);
 577
 578 static const char* const job_mode_table[_JOB_MODE_MAX] = {
 579         [JOB_FAIL] = "fail",
 580         [JOB_REPLACE] = "replace",
 581         [JOB_ISOLATE] = "isolate"
 582 };
 583
 584 DEFINE_STRING_TABLE_LOOKUP(job_mode, JobMode);