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[elogind.git] / manager.c
1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
2
3 #include <assert.h>
4 #include <errno.h>
5 #include <string.h>
6
7 #include "manager.h"
8 #include "hashmap.h"
9 #include "macro.h"
10 #include "strv.h"
11 #include "load-fragment.h"
12
13 Manager* manager_new(void) {
14         Manager *m;
15
16         if (!(m = new0(Manager, 1)))
17                 return NULL;
18
19         if (!(m->names = hashmap_new(string_hash_func, string_compare_func)))
20                 goto fail;
21
22         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
23                 goto fail;
24
25         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
26                 goto fail;
27
28         return m;
29
30 fail:
31         manager_free(m);
32         return NULL;
33 }
34
35 void manager_free(Manager *m) {
36         Name *n;
37         Job *j;
38
39         assert(m);
40
41         while ((n = hashmap_first(m->names)))
42                 name_free(n);
43
44         while ((j = hashmap_steal_first(m->transaction_jobs)))
45                 job_free(j);
46
47         hashmap_free(m->names);
48         hashmap_free(m->jobs);
49         hashmap_free(m->transaction_jobs);
50
51         free(m);
52 }
53
54 static void transaction_abort(Manager *m) {
55         Job *j;
56
57         assert(m);
58
59         while ((j = hashmap_first(m->transaction_jobs)))
60                 if (j->linked)
61                         manager_transaction_delete_job(m, j);
62                 else
63                         job_free(j);
64
65         assert(hashmap_isempty(m->transaction_jobs));
66         assert(!m->transaction_anchor);
67 }
68
69 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
70         JobDependency *l;
71
72         assert(m);
73
74         for (l = j ? j->subject_list : m->transaction_anchor; l; l = l->subject_next) {
75
76                 /* This link does not matter */
77                 if (!l->matters)
78                         continue;
79
80                 /* This name has already been marked */
81                 if (l->object->generation == generation)
82                         continue;
83
84                 l->object->matters_to_anchor = true;
85                 l->object->generation = generation;
86
87                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
88         }
89 }
90
91 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
92         return
93                 (a == c && b == d) ||
94                 (a == d && b == c);
95 }
96
97 static int types_merge(JobType *a, JobType b) {
98         if (*a == b)
99                 return 0;
100
101         if (types_match(*a, b, JOB_START, JOB_VERIFY_STARTED))
102                 *a = JOB_START;
103         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
104                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
105                  types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD_OR_START) ||
106                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
107                 *a = JOB_RELOAD_OR_START;
108         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
109                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
110                  types_match(*a, b, JOB_VERIFY_STARTED, JOB_RESTART) ||
111                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
112                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
113                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
114                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
115                 *a = JOB_RESTART;
116         else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD))
117                 *a = JOB_RELOAD;
118         else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_TRY_RESTART) ||
119                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
120                 *a = JOB_TRY_RESTART;
121
122         return -EEXIST;
123 }
124
125 static void manager_merge_and_delete_prospective_job(Manager *m, Job *j, Job *other, JobType t) {
126         JobDependency *l, *last;
127
128         assert(j);
129         assert(other);
130         assert(j->name == other->name);
131         assert(!j->linked);
132
133         j->type = t;
134         j->state = JOB_WAITING;
135
136         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
137
138         /* Patch us in as new owner of the JobDependency objects */
139         last = NULL;
140         for (l = other->subject_list; l; l = l->subject_next) {
141                 assert(l->subject == other);
142                 l->subject = j;
143                 last = l;
144         }
145
146         /* Merge both lists */
147         if (last) {
148                 last->subject_next = j->subject_list;
149                 if (j->subject_list)
150                         j->subject_list->subject_prev = last;
151                 j->subject_list = other->subject_list;
152         }
153
154         /* Patch us in as new owner of the JobDependency objects */
155         last = NULL;
156         for (l = other->object_list; l; l = l->object_next) {
157                 assert(l->object == other);
158                 l->object = j;
159                 last = l;
160         }
161
162         /* Merge both lists */
163         if (last) {
164                 last->object_next = j->object_list;
165                 if (j->object_list)
166                         j->object_list->object_prev = last;
167                 j->object_list = other->object_list;
168         }
169
170
171         /* Kill the other job */
172         other->subject_list = NULL;
173         other->object_list = NULL;
174         manager_transaction_delete_job(m, other);
175 }
176
177 static int transaction_merge_jobs(Manager *m) {
178         Job *j;
179         void *state;
180         int r;
181
182         assert(m);
183
184         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
185                 JobType t = j->type;
186                 Job *k;
187
188                 for (k = j->transaction_next; k; k = k->transaction_next)
189                         if ((r = types_merge(&t, k->type)) < 0)
190                                 return r;
191
192                 while ((k = j->transaction_next)) {
193                         if (j->linked) {
194                                 manager_merge_and_delete_prospective_job(m, k, j, t);
195                                 j = k;
196                         } else
197                                 manager_merge_and_delete_prospective_job(m, j, k, t);
198                 }
199
200                 assert(!j->transaction_next);
201                 assert(!j->transaction_prev);
202         }
203
204         return r;
205 }
206
207 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
208         void *state;
209         Name *n;
210         int r;
211
212         assert(m);
213         assert(j);
214
215         /* Did we find a loop? */
216         if (j->marker && j->generation == generation) {
217                 Job *k;
218
219                 /* So, we already have been here. We have a
220                  * loop. Let's try to break it. We go backwards in our
221                  * path and try to find a suitable job to remove. */
222
223                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
224                         if (!k->matters_to_anchor) {
225                                 manager_transaction_delete_job(m, k);
226                                 return -EAGAIN;
227                         }
228
229                         /* Check if this in fact was the beginning of
230                          * the loop */
231                         if (k == j)
232                                 break;
233                 }
234
235                 return -ELOOP;
236         }
237
238         j->marker = from;
239         j->generation = generation;
240
241         /* We assume that the the dependencies are both-ways, and
242          * hence can ignore NAME_AFTER */
243
244         SET_FOREACH(n, j->name->meta.dependencies[NAME_BEFORE], state) {
245                 Job *o;
246
247                 if (!(o = hashmap_get(m->transaction_jobs, n)))
248                         if (!(o = n->meta.job))
249                                 continue;
250
251                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
252                         return r;
253         }
254
255         return 0;
256 }
257
258 static int transaction_verify_order(Manager *m, unsigned *generation) {
259         bool again;
260         assert(m);
261         assert(generation);
262
263         do {
264                 Job *j;
265                 int r;
266                 void *state;
267
268                 again = false;
269
270                 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
271
272                         /* Assume merged */
273                         assert(!j->transaction_next);
274                         assert(!j->transaction_prev);
275
276                         if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)  {
277
278                                 /* There was a loop, but it was fixed,
279                                  * we need to restart our algorithm */
280                                 if (r == -EAGAIN) {
281                                         again = true;
282                                         break;
283                                 }
284
285                                 return r;
286                         }
287                 }
288         } while (again);
289
290         return 0;
291 }
292
293 static void transaction_collect_garbage(Manager *m) {
294         bool again;
295
296         assert(m);
297
298         do {
299                 void *state;
300                 Job *j;
301
302                 again = false;
303
304                 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
305                         if (j->object_list)
306                                 continue;
307
308                         manager_transaction_delete_job(m, j);
309                         again = true;
310                         break;
311                 }
312
313         } while (again);
314 }
315
316 static int transaction_is_destructive(Manager *m, JobMode mode) {
317         void *state;
318         Job *j;
319
320         assert(m);
321
322         /* Checks whether applying this transaction means that
323          * existing jobs would be replaced */
324
325         HASHMAP_FOREACH(j, m->transaction_jobs, state)
326                 if (j->name->meta.job && j->name->meta.job != j)
327                         return -EEXIST;
328
329         return 0;
330 }
331
332 static int transaction_apply(Manager *m, JobMode mode) {
333         void *state;
334         Job *j;
335         int r;
336
337         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
338                 if (j->linked)
339                         continue;
340
341                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
342                         goto rollback;
343         }
344
345         while ((j = hashmap_steal_first(m->transaction_jobs))) {
346                 if (j->linked)
347                         continue;
348
349                 if (j->name->meta.job)
350                         job_free(j->name->meta.job);
351
352                 j->name->meta.job = j;
353                 j->linked = true;
354
355                 /* We're fully installed. Now let's free data we don't
356                  * need anymore. */
357
358                 assert(!j->transaction_next);
359                 assert(!j->transaction_prev);
360
361                 while (j->subject_list)
362                         job_dependency_free(j->subject_list);
363                 while (j->object_list)
364                         job_dependency_free(j->object_list);
365         }
366
367         return 0;
368
369 rollback:
370
371         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
372                 if (j->linked)
373                         continue;
374
375                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
376         }
377
378         return r;
379 }
380
381
382 static int transaction_activate(Manager *m, JobMode mode) {
383         int r;
384         unsigned generation = 1;
385
386         assert(m);
387
388         /* This applies the changes recorded in transaction_jobs to
389          * the actual list of jobs, if possible. */
390
391         /* First step: figure out which jobs matter */
392         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
393
394         /* Second step: let's merge entries we can merge */
395         if ((r = transaction_merge_jobs(m)) < 0)
396                 goto rollback;
397
398         /* Third step: verify order makes sense */
399         if ((r = transaction_verify_order(m, &generation)) < 0)
400                 goto rollback;
401
402         /* Third step: do garbage colletion */
403         transaction_collect_garbage(m);
404
405         /* Fourth step: check whether we can actually apply this */
406         if (mode == JOB_FAIL)
407                 if ((r = transaction_is_destructive(m, mode)) < 0)
408                         goto rollback;
409
410         /* Fifth step: apply changes */
411         if ((r = transaction_apply(m, mode)) < 0)
412                 goto rollback;
413
414         assert(hashmap_isempty(m->transaction_jobs));
415         assert(!m->transaction_anchor);
416
417         return 0;
418
419 rollback:
420         transaction_abort(m);
421         return r;
422 }
423
424 static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool *is_new) {
425         Job *j, *f;
426         int r;
427
428         assert(m);
429         assert(name);
430
431         /* Looks for an axisting prospective job and returns that. If
432          * it doesn't exist it is created and added to the prospective
433          * jobs list. */
434
435         f = hashmap_get(m->transaction_jobs, name);
436
437         for (j = f; j; j = j->transaction_next) {
438                 assert(j->name == name);
439
440                 if (j->type == type) {
441                         if (is_new)
442                                 *is_new = false;
443                         return j;
444                 }
445         }
446
447         if (name->meta.job && name->meta.job->type == type)
448                 j = name->meta.job;
449         else if (!(j = job_new(m, type, name)))
450                 return NULL;
451
452         if ((r = hashmap_replace(m->transaction_jobs, name, j)) < 0) {
453                 job_free(j);
454                 return NULL;
455         }
456
457         j->transaction_next = f;
458
459         if (f)
460                 f->transaction_prev = j;
461
462         j->generation = 0;
463         j->marker = NULL;
464         j->matters_to_anchor = false;
465
466         if (is_new)
467                 *is_new = true;
468
469         return j;
470 }
471
472 void manager_transaction_delete_job(Manager *m, Job *j) {
473         assert(m);
474         assert(j);
475
476         if (j->transaction_prev)
477                 j->transaction_prev->transaction_next = j->transaction_next;
478         else if (j->transaction_next)
479                 hashmap_replace(m->transaction_jobs, j->name, j->transaction_next);
480         else
481                 hashmap_remove_value(m->transaction_jobs, j->name, j);
482
483         if (j->transaction_next)
484                 j->transaction_next->transaction_prev = j->transaction_prev;
485
486         j->transaction_prev = j->transaction_next = NULL;
487
488         while (j->subject_list)
489                 job_dependency_free(j->subject_list);
490         while (j->object_list)
491                 job_dependency_free(j->object_list);
492 }
493
494 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name *name, Job *by, bool matters, bool force, Job **_ret) {
495         Job *ret;
496         void *state;
497         Name *dep;
498         int r;
499         bool is_new;
500
501         assert(m);
502         assert(type < _JOB_TYPE_MAX);
503         assert(name);
504
505         /* First add the job. */
506         if (!(ret = transaction_add_one_job(m, type, name, &is_new)))
507                 return -ENOMEM;
508
509         /* Then, add a link to the job. */
510         if (!job_dependency_new(by, ret, matters))
511                 return -ENOMEM;
512
513         if (is_new) {
514                 /* Finally, recursively add in all dependencies. */
515                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
516                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRES], state)
517                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0)
518                                         goto fail;
519                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUIRES], state)
520                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0)
521                                         goto fail;
522                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_WANTS], state)
523                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0)
524                                         goto fail;
525                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUISITE], state)
526                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, true, force, NULL)) < 0)
527                                         goto fail;
528                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUISITE], state)
529                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, !force, force, NULL)) < 0)
530                                         goto fail;
531                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_CONFLICTS], state)
532                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0)
533                                         goto fail;
534
535                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
536
537                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRED_BY], state)
538                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0)
539                                         goto fail;
540                 }
541
542                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
543         }
544
545         return 0;
546
547 fail:
548         return r;
549 }
550
551 int manager_add_job(Manager *m, JobType type, Name *name, JobMode mode, bool force, Job **_ret) {
552         int r;
553         Job *ret;
554
555         assert(m);
556         assert(type < _JOB_TYPE_MAX);
557         assert(name);
558         assert(mode < _JOB_MODE_MAX);
559
560         if ((r = transaction_add_job_and_dependencies(m, type, name, NULL, true, force, &ret))) {
561                 transaction_abort(m);
562                 return r;
563         }
564
565         if ((r = transaction_activate(m, mode)) < 0)
566                 return r;
567
568         if (_ret)
569                 *_ret = ret;
570
571         return 0;
572 }
573
574 Job *manager_get_job(Manager *m, uint32_t id) {
575         assert(m);
576
577         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
578 }
579
580 Name *manager_get_name(Manager *m, const char *name) {
581         assert(m);
582         assert(name);
583
584         return hashmap_get(m->names, name);
585 }
586
587 static int verify_type(Name *name) {
588         char *n;
589         void *state;
590
591         assert(name);
592
593         /* Checks that all aliases of this name have the same and valid type */
594
595         SET_FOREACH(n, name->meta.names, state) {
596                 NameType t;
597
598                 if ((t = name_type_from_string(n)) == _NAME_TYPE_INVALID)
599                         return -EINVAL;
600
601                 if (name->meta.type == _NAME_TYPE_INVALID) {
602                         name->meta.type = t;
603                         continue;
604                 }
605
606                 if (name->meta.type != t)
607                         return -EINVAL;
608         }
609
610         if (name->meta.type == _NAME_TYPE_INVALID)
611                 return -EINVAL;
612
613         return 0;
614 }
615
616 static int service_load_sysv(Service *s) {
617         assert(s);
618
619         /* Load service data from SysV init scripts, preferably with
620          * LSB headers ... */
621
622         return 0;
623 }
624
625 static int name_load_fstab(Name *n) {
626         assert(n);
627         assert(n->meta.type == NAME_MOUNT || n->meta.type == NAME_AUTOMOUNT);
628
629         /* Load mount data from /etc/fstab */
630
631         return 0;
632 }
633
634 static int snapshot_load(Snapshot *s) {
635         assert(s);
636
637         /* Load snapshots from disk */
638
639         return 0;
640 }
641
642 static int name_load_dropin(Name *n) {
643         assert(n);
644
645         /* Load dependencies from drop-in directories */
646
647         return 0;
648 }
649
650 static int load(Name *name) {
651         int r;
652
653         assert(name);
654
655         if (name->meta.state != NAME_STUB)
656                 return 0;
657
658         if ((r = verify_type(name)) < 0)
659                 return r;
660
661         if (name->meta.type == NAME_SERVICE) {
662
663                 /* Load a .service file */
664                 if ((r = name_load_fragment(name)) == 0)
665                         goto finish;
666
667                 /* Load a classic init script */
668                 if (r == -ENOENT)
669                         if ((r = service_load_sysv(SERVICE(name))) == 0)
670                                 goto finish;
671
672         } else if (name->meta.type == NAME_MOUNT ||
673                    name->meta.type == NAME_AUTOMOUNT) {
674
675                 if ((r = name_load_fstab(name)) == 0)
676                         goto finish;
677
678         } else if (name->meta.type == NAME_SNAPSHOT) {
679
680                 if ((r = snapshot_load(SNAPSHOT(name))) == 0)
681                         goto finish;
682
683         } else {
684                 if ((r = name_load_fragment(name)) == 0)
685                         goto finish;
686         }
687
688         name->meta.state = NAME_FAILED;
689         return r;
690
691 finish:
692         if ((r = name_load_dropin(name)) < 0)
693                 return r;
694
695         if ((r = name_link_names(name, true)) < 0)
696                 return r;
697
698         name->meta.state = NAME_LOADED;
699         return 0;
700 }
701
702 static int dispatch_load_queue(Manager *m) {
703         Meta *meta;
704
705         assert(m);
706
707         /* Make sure we are not run recursively */
708         if (m->dispatching_load_queue)
709                 return 0;
710
711         m->dispatching_load_queue = true;
712
713         /* Dispatches the load queue. Takes a name from the queue and
714          * tries to load its data until the queue is empty */
715
716         while ((meta = m->load_queue)) {
717                 load(NAME(meta));
718                 LIST_REMOVE(Meta, m->load_queue, meta);
719         }
720
721         m->dispatching_load_queue = false;
722
723         return 0;
724 }
725
726 int manager_load_name(Manager *m, const char *name, Name **_ret) {
727         Name *ret;
728         NameType t;
729         int r;
730         char *n;
731
732         assert(m);
733         assert(name);
734         assert(_ret);
735
736         if (!name_is_valid(name))
737                 return -EINVAL;
738
739         /* This will load the service information files, but not actually
740          * start any services or anything */
741
742         if ((ret = manager_get_name(m, name)))
743                 goto finish;
744
745         if ((t = name_type_from_string(name)) == _NAME_TYPE_INVALID)
746                 return -EINVAL;
747
748         if (!(ret = name_new(m)))
749                 return -ENOMEM;
750
751         ret->meta.type = t;
752
753         if (!(n = strdup(name))) {
754                 name_free(ret);
755                 return -ENOMEM;
756         }
757
758         if (set_put(ret->meta.names, n) < 0) {
759                 name_free(ret);
760                 free(n);
761                 return -ENOMEM;
762         }
763
764         if ((r = name_link(ret)) < 0) {
765                 name_free(ret);
766                 return r;
767         }
768
769         /* At this point the new entry is created and linked. However,
770          * not loaded. Now load this entry and all its dependencies
771          * recursively */
772
773         dispatch_load_queue(m);
774
775 finish:
776
777         *_ret = ret;
778         return 0;
779 }
780
781 void manager_dump_jobs(Manager *s, FILE *f) {
782         void *state;
783         Job *j;
784
785         assert(s);
786         assert(f);
787
788         HASHMAP_FOREACH(j, s->jobs, state)
789                 job_dump(j, f, NULL);
790 }
791
792 void manager_dump_names(Manager *s, FILE *f) {
793         void *state;
794         Name *n;
795         const char *t;
796
797         assert(s);
798         assert(f);
799
800         HASHMAP_FOREACH_KEY(n, t, s->names, state)
801                 if (name_id(n) == t)
802                         name_dump(n, f, NULL);
803 }