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Make the fix for net/if.h fuckup even worse (#3287)
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1 /***
2 This file is part of systemd.
3
4 Copyright 2010 Lennart Poettering
5
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
10
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
18 ***/
19
20 #include <errno.h>
21 #include <sys/epoll.h>
22 #include <sys/inotify.h>
23 #include <unistd.h>
24
25 #include "bus-error.h"
26 #include "bus-util.h"
27 #include "dbus-path.h"
28 #include "fd-util.h"
29 #include "fs-util.h"
30 #include "glob-util.h"
31 #include "macro.h"
32 #include "mkdir.h"
33 #include "path.h"
34 #include "special.h"
35 #include "stat-util.h"
36 #include "string-table.h"
37 #include "string-util.h"
38 #include "unit-name.h"
39 #include "unit.h"
40
41 static const UnitActiveState state_translation_table[_PATH_STATE_MAX] = {
42 [PATH_DEAD] = UNIT_INACTIVE,
43 [PATH_WAITING] = UNIT_ACTIVE,
44 [PATH_RUNNING] = UNIT_ACTIVE,
45 [PATH_FAILED] = UNIT_FAILED
46 };
47
48 static int path_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);
49
50 int path_spec_watch(PathSpec *s, sd_event_io_handler_t handler) {
51
52 static const int flags_table[_PATH_TYPE_MAX] = {
53 [PATH_EXISTS] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB,
54 [PATH_EXISTS_GLOB] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB,
55 [PATH_CHANGED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO,
56 [PATH_MODIFIED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO|IN_MODIFY,
57 [PATH_DIRECTORY_NOT_EMPTY] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO
58 };
59
60 bool exists = false;
61 char *slash, *oldslash = NULL;
62 int r;
63
64 assert(s);
65 assert(s->unit);
66 assert(handler);
67
68 path_spec_unwatch(s);
69
70 s->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
71 if (s->inotify_fd < 0) {
72 r = -errno;
73 goto fail;
74 }
75
76 r = sd_event_add_io(s->unit->manager->event, &s->event_source, s->inotify_fd, EPOLLIN, handler, s);
77 if (r < 0)
78 goto fail;
79
80 (void) sd_event_source_set_description(s->event_source, "path");
81
82 /* This assumes the path was passed through path_kill_slashes()! */
83
84 for (slash = strchr(s->path, '/'); ; slash = strchr(slash+1, '/')) {
85 char *cut = NULL;
86 int flags;
87 char tmp;
88
89 if (slash) {
90 cut = slash + (slash == s->path);
91 tmp = *cut;
92 *cut = '\0';
93
94 flags = IN_MOVE_SELF | IN_DELETE_SELF | IN_ATTRIB | IN_CREATE | IN_MOVED_TO;
95 } else
96 flags = flags_table[s->type];
97
98 r = inotify_add_watch(s->inotify_fd, s->path, flags);
99 if (r < 0) {
100 if (errno == EACCES || errno == ENOENT) {
101 if (cut)
102 *cut = tmp;
103 break;
104 }
105
106 r = log_warning_errno(errno, "Failed to add watch on %s: %s", s->path, errno == ENOSPC ? "too many watches" : strerror(-r));
107 if (cut)
108 *cut = tmp;
109 goto fail;
110 } else {
111 exists = true;
112
113 /* Path exists, we don't need to watch parent too closely. */
114 if (oldslash) {
115 char *cut2 = oldslash + (oldslash == s->path);
116 char tmp2 = *cut2;
117 *cut2 = '\0';
118
119 (void) inotify_add_watch(s->inotify_fd, s->path, IN_MOVE_SELF);
120 /* Error is ignored, the worst can happen is we get spurious events. */
121
122 *cut2 = tmp2;
123 }
124 }
125
126 if (cut)
127 *cut = tmp;
128
129 if (slash)
130 oldslash = slash;
131 else {
132 /* whole path has been iterated over */
133 s->primary_wd = r;
134 break;
135 }
136 }
137
138 if (!exists) {
139 r = log_error_errno(errno, "Failed to add watch on any of the components of %s: %m", s->path);
140 /* either EACCESS or ENOENT */
141 goto fail;
142 }
143
144 return 0;
145
146 fail:
147 path_spec_unwatch(s);
148 return r;
149 }
150
151 void path_spec_unwatch(PathSpec *s) {
152 assert(s);
153
154 s->event_source = sd_event_source_unref(s->event_source);
155 s->inotify_fd = safe_close(s->inotify_fd);
156 }
157
158 int path_spec_fd_event(PathSpec *s, uint32_t revents) {
159 union inotify_event_buffer buffer;
160 struct inotify_event *e;
161 ssize_t l;
162 int r = 0;
163
164 if (revents != EPOLLIN) {
165 log_error("Got invalid poll event on inotify.");
166 return -EINVAL;
167 }
168
169 l = read(s->inotify_fd, &buffer, sizeof(buffer));
170 if (l < 0) {
171 if (errno == EAGAIN || errno == EINTR)
172 return 0;
173
174 return log_error_errno(errno, "Failed to read inotify event: %m");
175 }
176
177 FOREACH_INOTIFY_EVENT(e, buffer, l) {
178 if ((s->type == PATH_CHANGED || s->type == PATH_MODIFIED) &&
179 s->primary_wd == e->wd)
180 r = 1;
181 }
182
183 return r;
184 }
185
186 static bool path_spec_check_good(PathSpec *s, bool initial) {
187 bool good = false;
188
189 switch (s->type) {
190
191 case PATH_EXISTS:
192 good = access(s->path, F_OK) >= 0;
193 break;
194
195 case PATH_EXISTS_GLOB:
196 good = glob_exists(s->path) > 0;
197 break;
198
199 case PATH_DIRECTORY_NOT_EMPTY: {
200 int k;
201
202 k = dir_is_empty(s->path);
203 good = !(k == -ENOENT || k > 0);
204 break;
205 }
206
207 case PATH_CHANGED:
208 case PATH_MODIFIED: {
209 bool b;
210
211 b = access(s->path, F_OK) >= 0;
212 good = !initial && b != s->previous_exists;
213 s->previous_exists = b;
214 break;
215 }
216
217 default:
218 ;
219 }
220
221 return good;
222 }
223
224 static void path_spec_mkdir(PathSpec *s, mode_t mode) {
225 int r;
226
227 if (s->type == PATH_EXISTS || s->type == PATH_EXISTS_GLOB)
228 return;
229
230 r = mkdir_p_label(s->path, mode);
231 if (r < 0)
232 log_warning_errno(r, "mkdir(%s) failed: %m", s->path);
233 }
234
235 static void path_spec_dump(PathSpec *s, FILE *f, const char *prefix) {
236 fprintf(f,
237 "%s%s: %s\n",
238 prefix,
239 path_type_to_string(s->type),
240 s->path);
241 }
242
243 void path_spec_done(PathSpec *s) {
244 assert(s);
245 assert(s->inotify_fd == -1);
246
247 free(s->path);
248 }
249
250 static void path_init(Unit *u) {
251 Path *p = PATH(u);
252
253 assert(u);
254 assert(u->load_state == UNIT_STUB);
255
256 p->directory_mode = 0755;
257 }
258
259 void path_free_specs(Path *p) {
260 PathSpec *s;
261
262 assert(p);
263
264 while ((s = p->specs)) {
265 path_spec_unwatch(s);
266 LIST_REMOVE(spec, p->specs, s);
267 path_spec_done(s);
268 free(s);
269 }
270 }
271
272 static void path_done(Unit *u) {
273 Path *p = PATH(u);
274
275 assert(p);
276
277 path_free_specs(p);
278 }
279
280 static int path_add_mount_links(Path *p) {
281 PathSpec *s;
282 int r;
283
284 assert(p);
285
286 LIST_FOREACH(spec, s, p->specs) {
287 r = unit_require_mounts_for(UNIT(p), s->path);
288 if (r < 0)
289 return r;
290 }
291
292 return 0;
293 }
294
295 static int path_verify(Path *p) {
296 assert(p);
297
298 if (UNIT(p)->load_state != UNIT_LOADED)
299 return 0;
300
301 if (!p->specs) {
302 log_unit_error(UNIT(p), "Path unit lacks path setting. Refusing.");
303 return -EINVAL;
304 }
305
306 return 0;
307 }
308
309 static int path_add_default_dependencies(Path *p) {
310 int r;
311
312 assert(p);
313
314 if (!UNIT(p)->default_dependencies)
315 return 0;
316
317 r = unit_add_dependency_by_name(UNIT(p), UNIT_BEFORE, SPECIAL_PATHS_TARGET, NULL, true);
318 if (r < 0)
319 return r;
320
321 if (MANAGER_IS_SYSTEM(UNIT(p)->manager)) {
322 r = unit_add_two_dependencies_by_name(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true);
323 if (r < 0)
324 return r;
325 }
326
327 return unit_add_two_dependencies_by_name(UNIT(p), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
328 }
329
330 static int path_load(Unit *u) {
331 Path *p = PATH(u);
332 int r;
333
334 assert(u);
335 assert(u->load_state == UNIT_STUB);
336
337 r = unit_load_fragment_and_dropin(u);
338 if (r < 0)
339 return r;
340
341 if (u->load_state == UNIT_LOADED) {
342
343 if (set_isempty(u->dependencies[UNIT_TRIGGERS])) {
344 Unit *x;
345
346 r = unit_load_related_unit(u, ".service", &x);
347 if (r < 0)
348 return r;
349
350 r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, x, true);
351 if (r < 0)
352 return r;
353 }
354
355 r = path_add_mount_links(p);
356 if (r < 0)
357 return r;
358
359 r = path_add_default_dependencies(p);
360 if (r < 0)
361 return r;
362 }
363
364 return path_verify(p);
365 }
366
367 static void path_dump(Unit *u, FILE *f, const char *prefix) {
368 Path *p = PATH(u);
369 Unit *trigger;
370 PathSpec *s;
371
372 assert(p);
373 assert(f);
374
375 trigger = UNIT_TRIGGER(u);
376
377 fprintf(f,
378 "%sPath State: %s\n"
379 "%sResult: %s\n"
380 "%sUnit: %s\n"
381 "%sMakeDirectory: %s\n"
382 "%sDirectoryMode: %04o\n",
383 prefix, path_state_to_string(p->state),
384 prefix, path_result_to_string(p->result),
385 prefix, trigger ? trigger->id : "n/a",
386 prefix, yes_no(p->make_directory),
387 prefix, p->directory_mode);
388
389 LIST_FOREACH(spec, s, p->specs)
390 path_spec_dump(s, f, prefix);
391 }
392
393 static void path_unwatch(Path *p) {
394 PathSpec *s;
395
396 assert(p);
397
398 LIST_FOREACH(spec, s, p->specs)
399 path_spec_unwatch(s);
400 }
401
402 static int path_watch(Path *p) {
403 int r;
404 PathSpec *s;
405
406 assert(p);
407
408 LIST_FOREACH(spec, s, p->specs) {
409 r = path_spec_watch(s, path_dispatch_io);
410 if (r < 0)
411 return r;
412 }
413
414 return 0;
415 }
416
417 static void path_set_state(Path *p, PathState state) {
418 PathState old_state;
419 assert(p);
420
421 old_state = p->state;
422 p->state = state;
423
424 if (state != PATH_WAITING &&
425 (state != PATH_RUNNING || p->inotify_triggered))
426 path_unwatch(p);
427
428 if (state != old_state)
429 log_unit_debug(UNIT(p), "Changed %s -> %s", path_state_to_string(old_state), path_state_to_string(state));
430
431 unit_notify(UNIT(p), state_translation_table[old_state], state_translation_table[state], true);
432 }
433
434 static void path_enter_waiting(Path *p, bool initial, bool recheck);
435
436 static int path_coldplug(Unit *u) {
437 Path *p = PATH(u);
438
439 assert(p);
440 assert(p->state == PATH_DEAD);
441
442 if (p->deserialized_state != p->state) {
443
444 if (p->deserialized_state == PATH_WAITING ||
445 p->deserialized_state == PATH_RUNNING)
446 path_enter_waiting(p, true, true);
447 else
448 path_set_state(p, p->deserialized_state);
449 }
450
451 return 0;
452 }
453
454 static void path_enter_dead(Path *p, PathResult f) {
455 assert(p);
456
457 if (f != PATH_SUCCESS)
458 p->result = f;
459
460 path_set_state(p, p->result != PATH_SUCCESS ? PATH_FAILED : PATH_DEAD);
461 }
462
463 static void path_enter_running(Path *p) {
464 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
465 Unit *trigger;
466 int r;
467
468 assert(p);
469
470 /* Don't start job if we are supposed to go down */
471 if (unit_stop_pending(UNIT(p)))
472 return;
473
474 trigger = UNIT_TRIGGER(UNIT(p));
475 if (!trigger) {
476 log_unit_error(UNIT(p), "Unit to trigger vanished.");
477 path_enter_dead(p, PATH_FAILURE_RESOURCES);
478 return;
479 }
480
481 r = manager_add_job(UNIT(p)->manager, JOB_START, trigger, JOB_REPLACE, &error, NULL);
482 if (r < 0)
483 goto fail;
484
485 p->inotify_triggered = false;
486
487 r = path_watch(p);
488 if (r < 0)
489 goto fail;
490
491 path_set_state(p, PATH_RUNNING);
492 return;
493
494 fail:
495 log_unit_warning(UNIT(p), "Failed to queue unit startup job: %s", bus_error_message(&error, r));
496 path_enter_dead(p, PATH_FAILURE_RESOURCES);
497 }
498
499 static bool path_check_good(Path *p, bool initial) {
500 PathSpec *s;
501 bool good = false;
502
503 assert(p);
504
505 LIST_FOREACH(spec, s, p->specs) {
506 good = path_spec_check_good(s, initial);
507
508 if (good)
509 break;
510 }
511
512 return good;
513 }
514
515 static void path_enter_waiting(Path *p, bool initial, bool recheck) {
516 int r;
517
518 if (recheck)
519 if (path_check_good(p, initial)) {
520 log_unit_debug(UNIT(p), "Got triggered.");
521 path_enter_running(p);
522 return;
523 }
524
525 r = path_watch(p);
526 if (r < 0)
527 goto fail;
528
529 /* Hmm, so now we have created inotify watches, but the file
530 * might have appeared/been removed by now, so we must
531 * recheck */
532
533 if (recheck)
534 if (path_check_good(p, false)) {
535 log_unit_debug(UNIT(p), "Got triggered.");
536 path_enter_running(p);
537 return;
538 }
539
540 path_set_state(p, PATH_WAITING);
541 return;
542
543 fail:
544 log_unit_warning_errno(UNIT(p), r, "Failed to enter waiting state: %m");
545 path_enter_dead(p, PATH_FAILURE_RESOURCES);
546 }
547
548 static void path_mkdir(Path *p) {
549 PathSpec *s;
550
551 assert(p);
552
553 if (!p->make_directory)
554 return;
555
556 LIST_FOREACH(spec, s, p->specs)
557 path_spec_mkdir(s, p->directory_mode);
558 }
559
560 static int path_start(Unit *u) {
561 Path *p = PATH(u);
562 Unit *trigger;
563 int r;
564
565 assert(p);
566 assert(p->state == PATH_DEAD || p->state == PATH_FAILED);
567
568 trigger = UNIT_TRIGGER(u);
569 if (!trigger || trigger->load_state != UNIT_LOADED) {
570 log_unit_error(u, "Refusing to start, unit to trigger not loaded.");
571 return -ENOENT;
572 }
573
574 r = unit_start_limit_test(u);
575 if (r < 0) {
576 path_enter_dead(p, PATH_FAILURE_START_LIMIT_HIT);
577 return r;
578 }
579
580 path_mkdir(p);
581
582 p->result = PATH_SUCCESS;
583 path_enter_waiting(p, true, true);
584
585 return 1;
586 }
587
588 static int path_stop(Unit *u) {
589 Path *p = PATH(u);
590
591 assert(p);
592 assert(p->state == PATH_WAITING || p->state == PATH_RUNNING);
593
594 path_enter_dead(p, PATH_SUCCESS);
595 return 1;
596 }
597
598 static int path_serialize(Unit *u, FILE *f, FDSet *fds) {
599 Path *p = PATH(u);
600
601 assert(u);
602 assert(f);
603 assert(fds);
604
605 unit_serialize_item(u, f, "state", path_state_to_string(p->state));
606 unit_serialize_item(u, f, "result", path_result_to_string(p->result));
607
608 return 0;
609 }
610
611 static int path_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
612 Path *p = PATH(u);
613
614 assert(u);
615 assert(key);
616 assert(value);
617 assert(fds);
618
619 if (streq(key, "state")) {
620 PathState state;
621
622 state = path_state_from_string(value);
623 if (state < 0)
624 log_unit_debug(u, "Failed to parse state value: %s", value);
625 else
626 p->deserialized_state = state;
627
628 } else if (streq(key, "result")) {
629 PathResult f;
630
631 f = path_result_from_string(value);
632 if (f < 0)
633 log_unit_debug(u, "Failed to parse result value: %s", value);
634 else if (f != PATH_SUCCESS)
635 p->result = f;
636
637 } else
638 log_unit_debug(u, "Unknown serialization key: %s", key);
639
640 return 0;
641 }
642
643 _pure_ static UnitActiveState path_active_state(Unit *u) {
644 assert(u);
645
646 return state_translation_table[PATH(u)->state];
647 }
648
649 _pure_ static const char *path_sub_state_to_string(Unit *u) {
650 assert(u);
651
652 return path_state_to_string(PATH(u)->state);
653 }
654
655 static int path_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
656 PathSpec *s = userdata;
657 Path *p;
658 int changed;
659
660 assert(s);
661 assert(s->unit);
662 assert(fd >= 0);
663
664 p = PATH(s->unit);
665
666 if (p->state != PATH_WAITING &&
667 p->state != PATH_RUNNING)
668 return 0;
669
670 /* log_debug("inotify wakeup on %s.", u->id); */
671
672 LIST_FOREACH(spec, s, p->specs)
673 if (path_spec_owns_inotify_fd(s, fd))
674 break;
675
676 if (!s) {
677 log_error("Got event on unknown fd.");
678 goto fail;
679 }
680
681 changed = path_spec_fd_event(s, revents);
682 if (changed < 0)
683 goto fail;
684
685 /* If we are already running, then remember that one event was
686 * dispatched so that we restart the service only if something
687 * actually changed on disk */
688 p->inotify_triggered = true;
689
690 if (changed)
691 path_enter_running(p);
692 else
693 path_enter_waiting(p, false, true);
694
695 return 0;
696
697 fail:
698 path_enter_dead(p, PATH_FAILURE_RESOURCES);
699 return 0;
700 }
701
702 static void path_trigger_notify(Unit *u, Unit *other) {
703 Path *p = PATH(u);
704
705 assert(u);
706 assert(other);
707
708 /* Invoked whenever the unit we trigger changes state or gains
709 * or loses a job */
710
711 if (other->load_state != UNIT_LOADED)
712 return;
713
714 if (p->state == PATH_RUNNING &&
715 UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) {
716 log_unit_debug(UNIT(p), "Got notified about unit deactivation.");
717
718 /* Hmm, so inotify was triggered since the
719 * last activation, so I guess we need to
720 * recheck what is going on. */
721 path_enter_waiting(p, false, p->inotify_triggered);
722 }
723 }
724
725 static void path_reset_failed(Unit *u) {
726 Path *p = PATH(u);
727
728 assert(p);
729
730 if (p->state == PATH_FAILED)
731 path_set_state(p, PATH_DEAD);
732
733 p->result = PATH_SUCCESS;
734 }
735
736 static const char* const path_type_table[_PATH_TYPE_MAX] = {
737 [PATH_EXISTS] = "PathExists",
738 [PATH_EXISTS_GLOB] = "PathExistsGlob",
739 [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty",
740 [PATH_CHANGED] = "PathChanged",
741 [PATH_MODIFIED] = "PathModified",
742 };
743
744 DEFINE_STRING_TABLE_LOOKUP(path_type, PathType);
745
746 static const char* const path_result_table[_PATH_RESULT_MAX] = {
747 [PATH_SUCCESS] = "success",
748 [PATH_FAILURE_RESOURCES] = "resources",
749 [PATH_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
750 };
751
752 DEFINE_STRING_TABLE_LOOKUP(path_result, PathResult);
753
754 const UnitVTable path_vtable = {
755 .object_size = sizeof(Path),
756
757 .sections =
758 "Unit\0"
759 "Path\0"
760 "Install\0",
761
762 .init = path_init,
763 .done = path_done,
764 .load = path_load,
765
766 .coldplug = path_coldplug,
767
768 .dump = path_dump,
769
770 .start = path_start,
771 .stop = path_stop,
772
773 .serialize = path_serialize,
774 .deserialize_item = path_deserialize_item,
775
776 .active_state = path_active_state,
777 .sub_state_to_string = path_sub_state_to_string,
778
779 .trigger_notify = path_trigger_notify,
780
781 .reset_failed = path_reset_failed,
782
783 .bus_vtable = bus_path_vtable
784 };