1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
13 Manager* manager_new(void) {
16 if (!(m = new0(Manager, 1)))
19 if (!(m->names = hashmap_new(string_hash_func, string_compare_func)))
22 if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
25 if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
35 void manager_free(Manager *m) {
41 while ((n = hashmap_first(m->names)))
44 while ((j = hashmap_steal_first(m->transaction_jobs)))
47 hashmap_free(m->names);
48 hashmap_free(m->jobs);
49 hashmap_free(m->transaction_jobs);
54 static void transaction_delete_job(Manager *m, Job *j) {
58 /* Deletes one job from the transaction */
60 manager_transaction_unlink_job(m, j);
66 static void transaction_delete_name(Manager *m, Name *n) {
69 /* Deletes all jobs associated with a certain name from the
72 while ((j = hashmap_get(m->transaction_jobs, n)))
73 transaction_delete_job(m, j);
76 static void transaction_abort(Manager *m) {
81 while ((j = hashmap_first(m->transaction_jobs)))
83 transaction_delete_job(m, j);
87 assert(hashmap_isempty(m->transaction_jobs));
88 assert(!m->transaction_anchor);
91 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
96 /* A recursive sweep through the graph that marks all names
97 * that matter to the anchor job, i.e. are directly or
98 * indirectly a dependency of the anchor job via paths that
99 * are fully marked as mattering. */
101 for (l = j ? j->subject_list : m->transaction_anchor; l; l = l->subject_next) {
103 /* This link does not matter */
107 /* This name has already been marked */
108 if (l->object->generation == generation)
111 l->object->matters_to_anchor = true;
112 l->object->generation = generation;
114 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
118 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
119 JobDependency *l, *last;
123 assert(j->name == other->name);
126 /* Merges 'other' into 'j' and then deletes j. */
129 j->state = JOB_WAITING;
131 j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
133 /* Patch us in as new owner of the JobDependency objects */
135 for (l = other->subject_list; l; l = l->subject_next) {
136 assert(l->subject == other);
141 /* Merge both lists */
143 last->subject_next = j->subject_list;
145 j->subject_list->subject_prev = last;
146 j->subject_list = other->subject_list;
149 /* Patch us in as new owner of the JobDependency objects */
151 for (l = other->object_list; l; l = l->object_next) {
152 assert(l->object == other);
157 /* Merge both lists */
159 last->object_next = j->object_list;
161 j->object_list->object_prev = last;
162 j->object_list = other->object_list;
165 /* Kill the other job */
166 other->subject_list = NULL;
167 other->object_list = NULL;
168 transaction_delete_job(m, other);
171 static int delete_one_unmergable_job(Manager *m, Job *j) {
176 /* Tries to delete one item in the linked list
177 * j->transaction_next->transaction_next->... that conflicts
178 * whith another one, in an attempt to make an inconsistent
179 * transaction work. */
181 /* We rely here on the fact that if a merged with b does not
182 * merge with c, either a or b merge with c neither */
183 for (; j; j = j->transaction_next)
184 for (k = j->transaction_next; k; k = k->transaction_next) {
187 /* Is this one mergeable? Then skip it */
188 if (job_type_mergeable(j->type, k->type))
191 /* Ok, we found two that conflict, let's see if we can
192 * drop one of them */
193 if (!j->matters_to_anchor)
195 else if (!k->matters_to_anchor)
200 /* Ok, we can drop one, so let's do so. */
201 log_debug("Try to fix job merging by deleting job %s", name_id(d->name));
202 transaction_delete_job(m, d);
209 static int transaction_merge_jobs(Manager *m) {
216 /* First step, check whether any of the jobs for one specific
217 * task conflict. If so, try to drop one of them. */
218 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
223 for (k = j->transaction_next; k; k = k->transaction_next) {
224 if ((r = job_type_merge(&t, k->type)) >= 0)
227 /* OK, we could not merge all jobs for this
228 * action. Let's see if we can get rid of one
231 if ((r = delete_one_unmergable_job(m, j)) >= 0)
232 /* Ok, we managed to drop one, now
233 * let's ask our callers to call us
234 * again after garbage collecting */
237 /* We couldn't merge anything. Failure */
242 /* Second step, merge the jobs. */
243 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
247 /* Merge all transactions */
248 for (k = j->transaction_next; k; k = k->transaction_next)
249 assert_se(job_type_merge(&t, k->type) == 0);
251 /* If an active job is mergable, merge it too */
252 if (j->name->meta.job)
253 job_type_merge(&t, j->name->meta.job->type); /* Might fail. Which is OK */
255 while ((k = j->transaction_next)) {
257 transaction_merge_and_delete_job(m, k, j, t);
260 transaction_merge_and_delete_job(m, j, k, t);
263 assert(!j->transaction_next);
264 assert(!j->transaction_prev);
270 static bool name_matters_to_anchor(Name *n, Job *j) {
272 assert(!j->transaction_prev);
274 /* Checks whether at least one of the jobs for this name
275 * matters to the anchor. */
277 for (; j; j = j->transaction_next)
278 if (j->matters_to_anchor)
284 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
291 assert(!j->transaction_prev);
293 /* Does a recursive sweep through the ordering graph, looking
294 * for a cycle. If we find cycle we try to break it. */
296 /* Did we find a cycle? */
297 if (j->marker && j->generation == generation) {
300 /* So, we already have been here. We have a
301 * cycle. Let's try to break it. We go backwards in
302 * our path and try to find a suitable job to
303 * remove. We use the marker to find our way back,
304 * since smart how we are we stored our way back in
307 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
310 !name_matters_to_anchor(k->name, k)) {
311 /* Ok, we can drop this one, so let's
313 log_debug("Breaking order cycle by deleting job %s", name_id(k->name));
314 transaction_delete_name(m, k->name);
318 /* Check if this in fact was the beginning of
327 /* Make the marker point to where we come from, so that we can
328 * find our way backwards if we want to break a cycle */
330 j->generation = generation;
332 /* We assume that the the dependencies are bidirectional, and
333 * hence can ignore NAME_AFTER */
334 SET_FOREACH(n, j->name->meta.dependencies[NAME_BEFORE], state) {
337 /* Is there a job for this name? */
338 if (!(o = hashmap_get(m->transaction_jobs, n)))
340 /* Ok, there is no job for this in the
341 * transaction, but maybe there is already one
343 if (!(o = n->meta.job))
346 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
353 static int transaction_verify_order(Manager *m, unsigned *generation) {
361 /* Check if the ordering graph is cyclic. If it is, try to fix
362 * that up by dropping one of the jobs. */
364 HASHMAP_FOREACH(j, m->transaction_jobs, state)
365 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
371 static void transaction_collect_garbage(Manager *m) {
376 /* Drop jobs that are not required by any other job */
384 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
388 log_debug("Garbage collecting job %s", name_id(j->name));
390 transaction_delete_job(m, j);
398 static int transaction_is_destructive(Manager *m, JobMode mode) {
404 /* Checks whether applying this transaction means that
405 * existing jobs would be replaced */
407 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
410 assert(!j->transaction_prev);
411 assert(!j->transaction_next);
413 if (j->name->meta.job &&
414 j->name->meta.job != j &&
415 !job_type_is_superset(j->type, j->name->meta.job->type))
422 static void transaction_minimize_impact(Manager *m) {
426 /* Drops all unnecessary jobs that reverse already active jobs
427 * or that stop a running service. */
435 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
436 for (; j; j = j->transaction_next) {
438 /* If it matters, we shouldn't drop it */
439 if (j->matters_to_anchor)
442 /* Would this stop a running service?
443 * Would this change an existing job?
444 * If so, let's drop this entry */
445 if ((j->type != JOB_STOP || name_is_dead(j->name)) &&
446 (!j->name->meta.job || job_type_is_conflicting(j->type, j->name->meta.job->state)))
449 /* Ok, let's get rid of this */
450 transaction_delete_job(m, j);
462 static int transaction_apply(Manager *m, JobMode mode) {
467 /* Moves the transaction jobs to the set of active jobs */
469 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
471 assert(!j->transaction_prev);
472 assert(!j->transaction_next);
477 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
481 while ((j = hashmap_steal_first(m->transaction_jobs))) {
485 if (j->name->meta.job)
486 job_free(j->name->meta.job);
488 j->name->meta.job = j;
491 /* We're fully installed. Now let's free data we don't
494 assert(!j->transaction_next);
495 assert(!j->transaction_prev);
497 while (j->subject_list)
498 job_dependency_free(j->subject_list);
499 while (j->object_list)
500 job_dependency_free(j->object_list);
503 m->transaction_anchor = NULL;
509 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
513 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
519 static int transaction_activate(Manager *m, JobMode mode) {
521 unsigned generation = 1;
525 /* This applies the changes recorded in transaction_jobs to
526 * the actual list of jobs, if possible. */
528 /* First step: figure out which jobs matter */
529 transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
531 /* Second step: Try not to stop any running services if
532 * we don't have to. Don't try to reverse running
533 * jobs if we don't have to. */
534 transaction_minimize_impact(m);
537 /* Third step: Let's remove unneeded jobs that might
539 transaction_collect_garbage(m);
541 /* Fourth step: verify order makes sense and correct
542 * cycles if necessary and possible */
543 if ((r = transaction_verify_order(m, &generation)) >= 0)
549 /* Let's see if the resulting transaction ordering
550 * graph is still cyclic... */
554 /* Fifth step: let's drop unmergable entries if
555 * necessary and possible, merge entries we can
557 if ((r = transaction_merge_jobs(m)) >= 0)
563 /* Sixth step: an entry got dropped, let's garbage
564 * collect its dependencies. */
565 transaction_collect_garbage(m);
567 /* Let's see if the resulting transaction still has
568 * unmergable entries ... */
571 /* Seventh step: check whether we can actually apply this */
572 if (mode == JOB_FAIL)
573 if ((r = transaction_is_destructive(m, mode)) < 0)
576 /* Eights step: apply changes */
577 if ((r = transaction_apply(m, mode)) < 0)
580 assert(hashmap_isempty(m->transaction_jobs));
581 assert(!m->transaction_anchor);
586 transaction_abort(m);
590 static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool *is_new) {
597 /* Looks for an axisting prospective job and returns that. If
598 * it doesn't exist it is created and added to the prospective
601 f = hashmap_get(m->transaction_jobs, name);
603 for (j = f; j; j = j->transaction_next) {
604 assert(j->name == name);
606 if (j->type == type) {
613 if (name->meta.job && name->meta.job->type == type)
615 else if (!(j = job_new(m, type, name)))
618 if ((r = hashmap_replace(m->transaction_jobs, name, j)) < 0) {
623 j->transaction_next = f;
626 f->transaction_prev = j;
630 j->matters_to_anchor = false;
638 void manager_transaction_unlink_job(Manager *m, Job *j) {
642 if (j->transaction_prev)
643 j->transaction_prev->transaction_next = j->transaction_next;
644 else if (j->transaction_next)
645 hashmap_replace(m->transaction_jobs, j->name, j->transaction_next);
647 hashmap_remove_value(m->transaction_jobs, j->name, j);
649 if (j->transaction_next)
650 j->transaction_next->transaction_prev = j->transaction_prev;
652 j->transaction_prev = j->transaction_next = NULL;
654 while (j->subject_list)
655 job_dependency_free(j->subject_list);
657 while (j->object_list) {
658 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
660 job_dependency_free(j->object_list);
663 log_debug("Deleting job %s as dependency of job %s", name_id(other->name), name_id(j->name));
664 transaction_delete_job(m, other);
669 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name *name, Job *by, bool matters, bool force, Job **_ret) {
677 assert(type < _JOB_TYPE_MAX);
680 if (name->meta.state != NAME_LOADED)
683 if (!job_type_applicable(type, name->meta.type))
686 /* First add the job. */
687 if (!(ret = transaction_add_one_job(m, type, name, &is_new)))
690 /* Then, add a link to the job. */
691 if (!job_dependency_new(by, ret, matters))
695 /* Finally, recursively add in all dependencies. */
696 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
697 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRES], state)
698 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) != -EBADR)
700 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUIRES], state)
701 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) != -EBADR)
703 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_WANTS], state)
704 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) != -EBADR)
706 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUISITE], state)
707 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, true, force, NULL)) != -EBADR)
709 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUISITE], state)
710 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, !force, force, NULL)) != -EBADR)
712 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_CONFLICTS], state)
713 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) != -EBADR)
716 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
718 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRED_BY], state)
719 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) != -EBADR)
723 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
732 int manager_add_job(Manager *m, JobType type, Name *name, JobMode mode, bool force, Job **_ret) {
737 assert(type < _JOB_TYPE_MAX);
739 assert(mode < _JOB_MODE_MAX);
741 if ((r = transaction_add_job_and_dependencies(m, type, name, NULL, true, force, &ret))) {
742 transaction_abort(m);
746 if ((r = transaction_activate(m, mode)) < 0)
755 Job *manager_get_job(Manager *m, uint32_t id) {
758 return hashmap_get(m->jobs, UINT32_TO_PTR(id));
761 Name *manager_get_name(Manager *m, const char *name) {
765 return hashmap_get(m->names, name);
768 static int dispatch_load_queue(Manager *m) {
773 /* Make sure we are not run recursively */
774 if (m->dispatching_load_queue)
777 m->dispatching_load_queue = true;
779 /* Dispatches the load queue. Takes a name from the queue and
780 * tries to load its data until the queue is empty */
782 while ((meta = m->load_queue)) {
783 name_load(NAME(meta));
784 LIST_REMOVE(Meta, m->load_queue, meta);
787 m->dispatching_load_queue = false;
792 int manager_load_name(Manager *m, const char *name, Name **_ret) {
802 if (!name_is_valid(name))
805 /* This will load the service information files, but not actually
806 * start any services or anything */
808 if ((ret = manager_get_name(m, name)))
811 if ((t = name_type_from_string(name)) == _NAME_TYPE_INVALID)
814 if (!(ret = name_new(m)))
819 if (!(n = strdup(name))) {
824 if ((r = set_put(ret->meta.names, n)) < 0) {
830 if ((r = name_link(ret)) < 0) {
835 /* At this point the new entry is created and linked. However,
836 * not loaded. Now load this entry and all its dependencies
839 dispatch_load_queue(m);
847 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
854 HASHMAP_FOREACH(j, s->jobs, state)
855 job_dump(j, f, prefix);
858 void manager_dump_names(Manager *s, FILE *f, const char *prefix) {
866 HASHMAP_FOREACH_KEY(n, t, s->names, state)
868 name_dump(n, f, prefix);
871 void manager_clear_jobs(Manager *m) {
876 transaction_abort(m);
878 while ((j = hashmap_first(m->jobs)))