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