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