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