1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
8 #include <sys/signalfd.h>
19 Manager* manager_new(void) {
22 struct epoll_event ev;
24 if (!(m = new0(Manager, 1)))
27 m->signal_fd = m->epoll_fd = -1;
29 if (!(m->names = hashmap_new(string_hash_func, string_compare_func)))
32 if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
35 if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
38 if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
41 if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
44 assert_se(sigemptyset(&mask) == 0);
45 assert_se(sigaddset(&mask, SIGCHLD) == 0);
46 assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
48 if ((m->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
53 ev.data.fd = m->signal_fd;
55 if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_fd, &ev) < 0)
65 void manager_free(Manager *m) {
71 while ((n = hashmap_first(m->names)))
74 while ((j = hashmap_steal_first(m->transaction_jobs)))
77 hashmap_free(m->names);
78 hashmap_free(m->jobs);
79 hashmap_free(m->transaction_jobs);
80 hashmap_free(m->watch_pids);
83 close_nointr(m->epoll_fd);
84 if (m->signal_fd >= 0)
85 close_nointr(m->signal_fd);
90 static void transaction_delete_job(Manager *m, Job *j) {
94 /* Deletes one job from the transaction */
96 manager_transaction_unlink_job(m, j);
102 static void transaction_delete_name(Manager *m, Name *n) {
105 /* Deletes all jobs associated with a certain name from the
108 while ((j = hashmap_get(m->transaction_jobs, n)))
109 transaction_delete_job(m, j);
112 static void transaction_abort(Manager *m) {
117 while ((j = hashmap_first(m->transaction_jobs)))
119 transaction_delete_job(m, j);
123 assert(hashmap_isempty(m->transaction_jobs));
124 assert(!m->transaction_anchor);
127 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
132 /* A recursive sweep through the graph that marks all names
133 * that matter to the anchor job, i.e. are directly or
134 * indirectly a dependency of the anchor job via paths that
135 * are fully marked as mattering. */
140 l = m->transaction_anchor;
142 LIST_FOREACH(subject, l, l) {
144 /* This link does not matter */
148 /* This name has already been marked */
149 if (l->object->generation == generation)
152 l->object->matters_to_anchor = true;
153 l->object->generation = generation;
155 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
159 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
160 JobDependency *l, *last;
164 assert(j->name == other->name);
165 assert(!j->installed);
167 /* Merges 'other' into 'j' and then deletes j. */
170 j->state = JOB_WAITING;
171 j->forced = j->forced || other->forced;
173 j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
175 /* Patch us in as new owner of the JobDependency objects */
177 LIST_FOREACH(subject, l, other->subject_list) {
178 assert(l->subject == other);
183 /* Merge both lists */
185 last->subject_next = j->subject_list;
187 j->subject_list->subject_prev = last;
188 j->subject_list = other->subject_list;
191 /* Patch us in as new owner of the JobDependency objects */
193 LIST_FOREACH(object, l, other->object_list) {
194 assert(l->object == other);
199 /* Merge both lists */
201 last->object_next = j->object_list;
203 j->object_list->object_prev = last;
204 j->object_list = other->object_list;
207 /* Kill the other job */
208 other->subject_list = NULL;
209 other->object_list = NULL;
210 transaction_delete_job(m, other);
213 static int delete_one_unmergeable_job(Manager *m, Job *j) {
218 /* Tries to delete one item in the linked list
219 * j->transaction_next->transaction_next->... that conflicts
220 * whith another one, in an attempt to make an inconsistent
221 * transaction work. */
223 /* We rely here on the fact that if a merged with b does not
224 * merge with c, either a or b merge with c neither */
225 LIST_FOREACH(transaction, j, j)
226 LIST_FOREACH(transaction, k, j->transaction_next) {
229 /* Is this one mergeable? Then skip it */
230 if (job_type_is_mergeable(j->type, k->type))
233 /* Ok, we found two that conflict, let's see if we can
234 * drop one of them */
235 if (!j->matters_to_anchor)
237 else if (!k->matters_to_anchor)
242 /* Ok, we can drop one, so let's do so. */
243 log_debug("Try to fix job merging by deleting job %s/%s", name_id(d->name), job_type_to_string(d->type));
244 transaction_delete_job(m, d);
251 static int transaction_merge_jobs(Manager *m) {
258 /* First step, check whether any of the jobs for one specific
259 * task conflict. If so, try to drop one of them. */
260 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
265 LIST_FOREACH(transaction, k, j->transaction_next) {
266 if ((r = job_type_merge(&t, k->type)) >= 0)
269 /* OK, we could not merge all jobs for this
270 * action. Let's see if we can get rid of one
273 if ((r = delete_one_unmergeable_job(m, j)) >= 0)
274 /* Ok, we managed to drop one, now
275 * let's ask our callers to call us
276 * again after garbage collecting */
279 /* We couldn't merge anything. Failure */
284 /* Second step, merge the jobs. */
285 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
289 /* Merge all transactions */
290 LIST_FOREACH(transaction, k, j->transaction_next)
291 assert_se(job_type_merge(&t, k->type) == 0);
293 /* If an active job is mergeable, merge it too */
294 if (j->name->meta.job)
295 job_type_merge(&t, j->name->meta.job->type); /* Might fail. Which is OK */
297 while ((k = j->transaction_next)) {
299 transaction_merge_and_delete_job(m, k, j, t);
302 transaction_merge_and_delete_job(m, j, k, t);
305 assert(!j->transaction_next);
306 assert(!j->transaction_prev);
312 static bool name_matters_to_anchor(Name *n, Job *j) {
314 assert(!j->transaction_prev);
316 /* Checks whether at least one of the jobs for this name
317 * matters to the anchor. */
319 LIST_FOREACH(transaction, j, j)
320 if (j->matters_to_anchor)
326 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
333 assert(!j->transaction_prev);
335 /* Does a recursive sweep through the ordering graph, looking
336 * for a cycle. If we find cycle we try to break it. */
338 /* Did we find a cycle? */
339 if (j->marker && j->generation == generation) {
342 /* So, we already have been here. We have a
343 * cycle. Let's try to break it. We go backwards in
344 * our path and try to find a suitable job to
345 * remove. We use the marker to find our way back,
346 * since smart how we are we stored our way back in
349 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
352 !name_matters_to_anchor(k->name, k)) {
353 /* Ok, we can drop this one, so let's
355 log_debug("Breaking order cycle by deleting job %s/%s", name_id(k->name), job_type_to_string(k->type));
356 transaction_delete_name(m, k->name);
360 /* Check if this in fact was the beginning of
369 /* Make the marker point to where we come from, so that we can
370 * find our way backwards if we want to break a cycle */
372 j->generation = generation;
374 /* We assume that the the dependencies are bidirectional, and
375 * hence can ignore NAME_AFTER */
376 SET_FOREACH(n, j->name->meta.dependencies[NAME_BEFORE], i) {
379 /* Is there a job for this name? */
380 if (!(o = hashmap_get(m->transaction_jobs, n)))
382 /* Ok, there is no job for this in the
383 * transaction, but maybe there is already one
385 if (!(o = n->meta.job))
388 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
395 static int transaction_verify_order(Manager *m, unsigned *generation) {
403 /* Check if the ordering graph is cyclic. If it is, try to fix
404 * that up by dropping one of the jobs. */
406 HASHMAP_FOREACH(j, m->transaction_jobs, i)
407 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
413 static void transaction_collect_garbage(Manager *m) {
418 /* Drop jobs that are not required by any other job */
426 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
430 log_debug("Garbage collecting job %s/%s", name_id(j->name), job_type_to_string(j->type));
431 transaction_delete_job(m, j);
439 static int transaction_is_destructive(Manager *m, JobMode mode) {
445 /* Checks whether applying this transaction means that
446 * existing jobs would be replaced */
448 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
451 assert(!j->transaction_prev);
452 assert(!j->transaction_next);
454 if (j->name->meta.job &&
455 j->name->meta.job != j &&
456 !job_type_is_superset(j->type, j->name->meta.job->type))
463 static void transaction_minimize_impact(Manager *m) {
467 /* Drops all unnecessary jobs that reverse already active jobs
468 * or that stop a running service. */
476 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
477 LIST_FOREACH(transaction, j, j) {
479 /* If it matters, we shouldn't drop it */
480 if (j->matters_to_anchor)
483 /* Would this stop a running service?
484 * Would this change an existing job?
485 * If so, let's drop this entry */
486 if ((j->type != JOB_STOP || NAME_IS_INACTIVE_OR_DEACTIVATING(name_active_state(j->name))) &&
487 (!j->name->meta.job || job_type_is_conflicting(j->type, j->name->meta.job->state)))
490 /* Ok, let's get rid of this */
491 log_debug("Deleting %s/%s to minimize impact", name_id(j->name), job_type_to_string(j->type));
492 transaction_delete_job(m, j);
504 static int transaction_apply(Manager *m, JobMode mode) {
509 /* Moves the transaction jobs to the set of active jobs */
511 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
513 assert(!j->transaction_prev);
514 assert(!j->transaction_next);
519 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
523 while ((j = hashmap_steal_first(m->transaction_jobs))) {
527 if (j->name->meta.job)
528 job_free(j->name->meta.job);
530 j->name->meta.job = j;
533 /* We're fully installed. Now let's free data we don't
536 assert(!j->transaction_next);
537 assert(!j->transaction_prev);
539 while (j->subject_list)
540 job_dependency_free(j->subject_list);
541 while (j->object_list)
542 job_dependency_free(j->object_list);
545 m->transaction_anchor = NULL;
551 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
555 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
561 static int transaction_activate(Manager *m, JobMode mode) {
563 unsigned generation = 1;
567 /* This applies the changes recorded in transaction_jobs to
568 * the actual list of jobs, if possible. */
570 /* First step: figure out which jobs matter */
571 transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
573 /* Second step: Try not to stop any running services if
574 * we don't have to. Don't try to reverse running
575 * jobs if we don't have to. */
576 transaction_minimize_impact(m);
579 /* Third step: Let's remove unneeded jobs that might
581 transaction_collect_garbage(m);
583 /* Fourth step: verify order makes sense and correct
584 * cycles if necessary and possible */
585 if ((r = transaction_verify_order(m, &generation)) >= 0)
591 /* Let's see if the resulting transaction ordering
592 * graph is still cyclic... */
596 /* Fifth step: let's drop unmergeable entries if
597 * necessary and possible, merge entries we can
599 if ((r = transaction_merge_jobs(m)) >= 0)
605 /* Sixth step: an entry got dropped, let's garbage
606 * collect its dependencies. */
607 transaction_collect_garbage(m);
609 /* Let's see if the resulting transaction still has
610 * unmergeable entries ... */
613 /* Seventh step: check whether we can actually apply this */
614 if (mode == JOB_FAIL)
615 if ((r = transaction_is_destructive(m, mode)) < 0)
618 /* Eights step: apply changes */
619 if ((r = transaction_apply(m, mode)) < 0)
622 assert(hashmap_isempty(m->transaction_jobs));
623 assert(!m->transaction_anchor);
628 transaction_abort(m);
632 static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool force, bool *is_new) {
639 /* Looks for an axisting prospective job and returns that. If
640 * it doesn't exist it is created and added to the prospective
643 f = hashmap_get(m->transaction_jobs, name);
645 LIST_FOREACH(transaction, j, f) {
646 assert(j->name == name);
648 if (j->type == type) {
655 if (name->meta.job && name->meta.job->type == type)
657 else if (!(j = job_new(m, type, name)))
662 j->matters_to_anchor = false;
665 LIST_PREPEND(Job, transaction, f, j);
667 if ((r = hashmap_replace(m->transaction_jobs, name, f)) < 0) {
678 void manager_transaction_unlink_job(Manager *m, Job *j) {
682 if (j->transaction_prev)
683 j->transaction_prev->transaction_next = j->transaction_next;
684 else if (j->transaction_next)
685 hashmap_replace(m->transaction_jobs, j->name, j->transaction_next);
687 hashmap_remove_value(m->transaction_jobs, j->name, j);
689 if (j->transaction_next)
690 j->transaction_next->transaction_prev = j->transaction_prev;
692 j->transaction_prev = j->transaction_next = NULL;
694 while (j->subject_list)
695 job_dependency_free(j->subject_list);
697 while (j->object_list) {
698 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
700 job_dependency_free(j->object_list);
703 log_debug("Deleting job %s/%s as dependency of job %s/%s",
704 name_id(other->name), job_type_to_string(other->type),
705 name_id(j->name), job_type_to_string(j->type));
706 transaction_delete_job(m, other);
711 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name *name, Job *by, bool matters, bool force, Job **_ret) {
719 assert(type < _JOB_TYPE_MAX);
722 if (name->meta.load_state != NAME_LOADED)
725 if (!name_job_is_applicable(name, type))
728 /* First add the job. */
729 if (!(ret = transaction_add_one_job(m, type, name, force, &is_new)))
732 /* Then, add a link to the job. */
733 if (!job_dependency_new(by, ret, matters))
737 /* Finally, recursively add in all dependencies. */
738 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
739 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRES], i)
740 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
742 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUIRES], i)
743 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
745 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_WANTS], i)
746 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0 && r != -EBADR)
748 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUISITE], i)
749 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
751 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUISITE], i)
752 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
754 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_CONFLICTS], i)
755 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
758 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
760 SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRED_BY], i)
761 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
765 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
774 int manager_add_job(Manager *m, JobType type, Name *name, JobMode mode, bool force, Job **_ret) {
779 assert(type < _JOB_TYPE_MAX);
781 assert(mode < _JOB_MODE_MAX);
783 if ((r = transaction_add_job_and_dependencies(m, type, name, NULL, true, force, &ret))) {
784 transaction_abort(m);
788 if ((r = transaction_activate(m, mode)) < 0)
797 Job *manager_get_job(Manager *m, uint32_t id) {
800 return hashmap_get(m->jobs, UINT32_TO_PTR(id));
803 Name *manager_get_name(Manager *m, const char *name) {
807 return hashmap_get(m->names, name);
810 static void dispatch_load_queue(Manager *m) {
815 /* Make sure we are not run recursively */
816 if (m->dispatching_load_queue)
819 m->dispatching_load_queue = true;
821 /* Dispatches the load queue. Takes a name from the queue and
822 * tries to load its data until the queue is empty */
824 while ((meta = m->load_queue)) {
825 assert(meta->in_load_queue);
827 name_load(NAME(meta));
830 m->dispatching_load_queue = false;
833 int manager_load_name(Manager *m, const char *name, Name **_ret) {
841 /* This will load the service information files, but not actually
842 * start any services or anything */
844 if ((ret = manager_get_name(m, name))) {
849 if (!(ret = name_new(m)))
852 if ((r = name_add_name(ret, name)) < 0) {
857 name_add_to_load_queue(ret);
858 dispatch_load_queue(m);
864 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
871 HASHMAP_FOREACH(j, s->jobs, i)
872 job_dump(j, f, prefix);
875 void manager_dump_names(Manager *s, FILE *f, const char *prefix) {
883 HASHMAP_FOREACH_KEY(n, t, s->names, i)
885 name_dump(n, f, prefix);
888 void manager_clear_jobs(Manager *m) {
893 transaction_abort(m);
895 while ((j = hashmap_first(m->jobs)))
899 void manager_dispatch_run_queue(Manager *m) {
902 if (m->dispatching_run_queue)
905 m->dispatching_run_queue = true;
907 while ((j = m->run_queue)) {
908 assert(j->installed);
909 assert(j->in_run_queue);
911 job_run_and_invalidate(j);
914 m->dispatching_run_queue = false;
917 static int manager_dispatch_sigchld(Manager *m) {
925 if (waitid(P_ALL, 0, &si, WNOHANG) < 0)
931 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
934 if (!(n = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
937 NAME_VTABLE(n)->sigchld_event(n, si.si_pid, si.si_code, si.si_status);
943 static int manager_process_signal_fd(Manager *m) {
945 struct signalfd_siginfo sfsi;
946 bool sigchld = false;
951 if ((n = read(m->signal_fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
962 if (sfsi.ssi_signo == SIGCHLD)
967 return manager_dispatch_sigchld(m);
972 static int process_event(Manager *m, struct epoll_event *ev) {
978 switch (ev->data.u32) {
981 assert(ev->data.fd == m->signal_fd);
983 /* An incoming signal? */
984 if (ev->events != POLLIN)
987 if ((r = manager_process_signal_fd(m)) < 0)
995 /* Some fd event, to be dispatched to the names */
996 assert_se(n = ev->data.ptr);
997 NAME_VTABLE(n)->fd_event(n, ev->data.fd, ev->events);
1001 case MANAGER_TIMER: {
1006 /* Some timer event, to be dispatched to the names */
1007 if ((k = read(ev->data.fd, &u, sizeof(u))) != sizeof(u)) {
1009 if (k < 0 && (errno == EINTR || errno == EAGAIN))
1012 return k < 0 ? -errno : -EIO;
1015 assert_se(n = ev->data.ptr);
1016 NAME_VTABLE(n)->timer_event(n, ev->data.fd, u);
1021 assert_not_reached("Unknown epoll event type.");
1027 int manager_loop(Manager *m) {
1033 struct epoll_event events[32];
1036 manager_dispatch_run_queue(m);
1038 if ((n = epoll_wait(m->epoll_fd, events, ELEMENTSOF(events), -1)) < 0) {
1040 if (errno == -EINTR)
1046 for (i = 0; i < n; i++)
1047 if ((r = process_event(m, events + i)) < 0)