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52ad194e | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
60f067b4 JS |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2013 Lennart Poettering | |
6 | ||
7 | systemd is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU Lesser General Public License as published by | |
9 | the Free Software Foundation; either version 2.1 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | systemd is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | Lesser General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU Lesser General Public License | |
18 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
19 | ***/ | |
20 | ||
21 | #include "sd-bus.h" | |
db2df898 MP |
22 | |
23 | #include "alloc-util.h" | |
60f067b4 JS |
24 | #include "bus-internal.h" |
25 | #include "bus-track.h" | |
db2df898 | 26 | #include "bus-util.h" |
60f067b4 | 27 | |
8a584da2 MP |
28 | struct track_item { |
29 | unsigned n_ref; | |
30 | char *name; | |
31 | sd_bus_slot *slot; | |
32 | }; | |
33 | ||
60f067b4 JS |
34 | struct sd_bus_track { |
35 | unsigned n_ref; | |
8a584da2 | 36 | unsigned n_adding; /* are we in the process of adding a new name? */ |
60f067b4 JS |
37 | sd_bus *bus; |
38 | sd_bus_track_handler_t handler; | |
39 | void *userdata; | |
40 | Hashmap *names; | |
41 | LIST_FIELDS(sd_bus_track, queue); | |
42 | Iterator iterator; | |
8a584da2 MP |
43 | bool in_list:1; /* In bus->tracks? */ |
44 | bool in_queue:1; /* In bus->track_queue? */ | |
45 | bool modified:1; | |
46 | bool recursive:1; | |
47 | ||
48 | LIST_FIELDS(sd_bus_track, tracks); | |
60f067b4 JS |
49 | }; |
50 | ||
51 | #define MATCH_PREFIX \ | |
52 | "type='signal'," \ | |
53 | "sender='org.freedesktop.DBus'," \ | |
54 | "path='/org/freedesktop/DBus'," \ | |
55 | "interface='org.freedesktop.DBus'," \ | |
56 | "member='NameOwnerChanged'," \ | |
57 | "arg0='" | |
58 | ||
59 | #define MATCH_SUFFIX \ | |
60 | "'" | |
61 | ||
62 | #define MATCH_FOR_NAME(name) \ | |
63 | ({ \ | |
64 | char *_x; \ | |
65 | size_t _l = strlen(name); \ | |
52ad194e | 66 | _x = alloca(STRLEN(MATCH_PREFIX)+_l+STRLEN(MATCH_SUFFIX)+1); \ |
60f067b4 JS |
67 | strcpy(stpcpy(stpcpy(_x, MATCH_PREFIX), name), MATCH_SUFFIX); \ |
68 | _x; \ | |
69 | }) | |
70 | ||
8a584da2 MP |
71 | static struct track_item* track_item_free(struct track_item *i) { |
72 | ||
73 | if (!i) | |
74 | return NULL; | |
75 | ||
76 | sd_bus_slot_unref(i->slot); | |
77 | free(i->name); | |
78 | return mfree(i); | |
79 | } | |
80 | ||
81 | DEFINE_TRIVIAL_CLEANUP_FUNC(struct track_item*, track_item_free); | |
82 | ||
60f067b4 JS |
83 | static void bus_track_add_to_queue(sd_bus_track *track) { |
84 | assert(track); | |
85 | ||
8a584da2 MP |
86 | /* Adds the bus track object to the queue of objects we should dispatch next, subject to a number of |
87 | * conditions. */ | |
88 | ||
89 | /* Already in the queue? */ | |
60f067b4 JS |
90 | if (track->in_queue) |
91 | return; | |
92 | ||
8a584da2 MP |
93 | /* if we are currently in the process of adding a new name, then let's not enqueue this just yet, let's wait |
94 | * until the addition is complete. */ | |
95 | if (track->n_adding > 0) | |
96 | return; | |
97 | ||
98 | /* still referenced? */ | |
99 | if (hashmap_size(track->names) > 0) | |
100 | return; | |
101 | ||
102 | /* Nothing to call? */ | |
60f067b4 JS |
103 | if (!track->handler) |
104 | return; | |
105 | ||
8a584da2 MP |
106 | /* Already closed? */ |
107 | if (!track->in_list) | |
108 | return; | |
109 | ||
60f067b4 JS |
110 | LIST_PREPEND(queue, track->bus->track_queue, track); |
111 | track->in_queue = true; | |
112 | } | |
113 | ||
114 | static void bus_track_remove_from_queue(sd_bus_track *track) { | |
115 | assert(track); | |
116 | ||
117 | if (!track->in_queue) | |
118 | return; | |
119 | ||
120 | LIST_REMOVE(queue, track->bus->track_queue, track); | |
121 | track->in_queue = false; | |
122 | } | |
123 | ||
8a584da2 MP |
124 | static int bus_track_remove_name_fully(sd_bus_track *track, const char *name) { |
125 | struct track_item *i; | |
126 | ||
127 | assert(track); | |
128 | assert(name); | |
129 | ||
130 | i = hashmap_remove(track->names, name); | |
131 | if (!i) | |
132 | return 0; | |
133 | ||
134 | track_item_free(i); | |
135 | ||
136 | bus_track_add_to_queue(track); | |
137 | ||
138 | track->modified = true; | |
139 | return 1; | |
140 | } | |
141 | ||
60f067b4 JS |
142 | _public_ int sd_bus_track_new( |
143 | sd_bus *bus, | |
144 | sd_bus_track **track, | |
145 | sd_bus_track_handler_t handler, | |
146 | void *userdata) { | |
147 | ||
148 | sd_bus_track *t; | |
149 | ||
150 | assert_return(bus, -EINVAL); | |
151 | assert_return(track, -EINVAL); | |
152 | ||
e3bff60a MP |
153 | if (!bus->bus_client) |
154 | return -EINVAL; | |
155 | ||
60f067b4 JS |
156 | t = new0(sd_bus_track, 1); |
157 | if (!t) | |
158 | return -ENOMEM; | |
159 | ||
160 | t->n_ref = 1; | |
161 | t->handler = handler; | |
162 | t->userdata = userdata; | |
163 | t->bus = sd_bus_ref(bus); | |
164 | ||
8a584da2 MP |
165 | LIST_PREPEND(tracks, bus->tracks, t); |
166 | t->in_list = true; | |
167 | ||
60f067b4 JS |
168 | bus_track_add_to_queue(t); |
169 | ||
170 | *track = t; | |
171 | return 0; | |
172 | } | |
173 | ||
174 | _public_ sd_bus_track* sd_bus_track_ref(sd_bus_track *track) { | |
4c89c718 MP |
175 | |
176 | if (!track) | |
177 | return NULL; | |
60f067b4 JS |
178 | |
179 | assert(track->n_ref > 0); | |
180 | ||
181 | track->n_ref++; | |
182 | ||
183 | return track; | |
184 | } | |
185 | ||
186 | _public_ sd_bus_track* sd_bus_track_unref(sd_bus_track *track) { | |
60f067b4 JS |
187 | if (!track) |
188 | return NULL; | |
189 | ||
190 | assert(track->n_ref > 0); | |
191 | ||
192 | if (track->n_ref > 1) { | |
aa27b158 | 193 | track->n_ref--; |
60f067b4 JS |
194 | return NULL; |
195 | } | |
196 | ||
8a584da2 MP |
197 | if (track->in_list) |
198 | LIST_REMOVE(tracks, track->bus->tracks, track); | |
60f067b4 JS |
199 | |
200 | bus_track_remove_from_queue(track); | |
52ad194e | 201 | hashmap_free_with_destructor(track->names, track_item_free); |
60f067b4 | 202 | sd_bus_unref(track->bus); |
8a584da2 | 203 | return mfree(track); |
60f067b4 JS |
204 | } |
205 | ||
e3bff60a | 206 | static int on_name_owner_changed(sd_bus_message *message, void *userdata, sd_bus_error *error) { |
60f067b4 JS |
207 | sd_bus_track *track = userdata; |
208 | const char *name, *old, *new; | |
209 | int r; | |
210 | ||
60f067b4 JS |
211 | assert(message); |
212 | assert(track); | |
213 | ||
214 | r = sd_bus_message_read(message, "sss", &name, &old, &new); | |
215 | if (r < 0) | |
216 | return 0; | |
217 | ||
8a584da2 | 218 | bus_track_remove_name_fully(track, name); |
60f067b4 JS |
219 | return 0; |
220 | } | |
221 | ||
222 | _public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) { | |
8a584da2 MP |
223 | _cleanup_(track_item_freep) struct track_item *n = NULL; |
224 | struct track_item *i; | |
60f067b4 JS |
225 | const char *match; |
226 | int r; | |
227 | ||
228 | assert_return(track, -EINVAL); | |
229 | assert_return(service_name_is_valid(name), -EINVAL); | |
230 | ||
8a584da2 MP |
231 | i = hashmap_get(track->names, name); |
232 | if (i) { | |
233 | if (track->recursive) { | |
234 | unsigned k = track->n_ref + 1; | |
235 | ||
236 | if (k < track->n_ref) /* Check for overflow */ | |
237 | return -EOVERFLOW; | |
238 | ||
239 | track->n_ref = k; | |
240 | } | |
241 | ||
242 | bus_track_remove_from_queue(track); | |
243 | return 0; | |
244 | } | |
245 | ||
5eef597e | 246 | r = hashmap_ensure_allocated(&track->names, &string_hash_ops); |
60f067b4 JS |
247 | if (r < 0) |
248 | return r; | |
249 | ||
8a584da2 | 250 | n = new0(struct track_item, 1); |
60f067b4 JS |
251 | if (!n) |
252 | return -ENOMEM; | |
8a584da2 MP |
253 | n->name = strdup(name); |
254 | if (!n->name) | |
255 | return -ENOMEM; | |
60f067b4 JS |
256 | |
257 | /* First, subscribe to this name */ | |
8a584da2 MP |
258 | match = MATCH_FOR_NAME(name); |
259 | ||
260 | bus_track_remove_from_queue(track); /* don't dispatch this while we work in it */ | |
261 | ||
262 | track->n_adding++; /* make sure we aren't dispatched while we synchronously add this match */ | |
263 | r = sd_bus_add_match(track->bus, &n->slot, match, on_name_owner_changed, track); | |
264 | track->n_adding--; | |
265 | if (r < 0) { | |
266 | bus_track_add_to_queue(track); | |
60f067b4 | 267 | return r; |
8a584da2 | 268 | } |
60f067b4 | 269 | |
8a584da2 MP |
270 | r = hashmap_put(track->names, n->name, n); |
271 | if (r < 0) { | |
272 | bus_track_add_to_queue(track); | |
60f067b4 | 273 | return r; |
8a584da2 | 274 | } |
60f067b4 | 275 | |
8a584da2 MP |
276 | /* Second, check if it is currently existing, or maybe doesn't, or maybe disappeared already. */ |
277 | track->n_adding++; /* again, make sure this isn't dispatch while we are working in it */ | |
278 | r = sd_bus_get_name_creds(track->bus, name, 0, NULL); | |
279 | track->n_adding--; | |
60f067b4 | 280 | if (r < 0) { |
8a584da2 MP |
281 | hashmap_remove(track->names, name); |
282 | bus_track_add_to_queue(track); | |
60f067b4 JS |
283 | return r; |
284 | } | |
285 | ||
8a584da2 | 286 | n->n_ref = 1; |
60f067b4 | 287 | n = NULL; |
60f067b4 JS |
288 | |
289 | bus_track_remove_from_queue(track); | |
290 | track->modified = true; | |
291 | ||
292 | return 1; | |
293 | } | |
294 | ||
295 | _public_ int sd_bus_track_remove_name(sd_bus_track *track, const char *name) { | |
8a584da2 | 296 | struct track_item *i; |
60f067b4 JS |
297 | |
298 | assert_return(name, -EINVAL); | |
299 | ||
8a584da2 | 300 | if (!track) /* Treat a NULL track object as an empty track object */ |
60f067b4 JS |
301 | return 0; |
302 | ||
8a584da2 MP |
303 | if (!track->recursive) |
304 | return bus_track_remove_name_fully(track, name); | |
60f067b4 | 305 | |
8a584da2 MP |
306 | i = hashmap_get(track->names, name); |
307 | if (!i) | |
308 | return -EUNATCH; | |
309 | if (i->n_ref <= 0) | |
310 | return -EUNATCH; | |
60f067b4 | 311 | |
8a584da2 MP |
312 | i->n_ref--; |
313 | ||
314 | if (i->n_ref <= 0) | |
315 | return bus_track_remove_name_fully(track, name); | |
60f067b4 JS |
316 | |
317 | return 1; | |
318 | } | |
319 | ||
320 | _public_ unsigned sd_bus_track_count(sd_bus_track *track) { | |
8a584da2 MP |
321 | |
322 | if (!track) /* Let's consider a NULL object equivalent to an empty object */ | |
60f067b4 JS |
323 | return 0; |
324 | ||
8a584da2 MP |
325 | /* This signature really should have returned an int, so that we can propagate errors. But well, ... Also, note |
326 | * that this returns the number of names being watched, and multiple references to the same name are not | |
327 | * counted. */ | |
328 | ||
60f067b4 JS |
329 | return hashmap_size(track->names); |
330 | } | |
331 | ||
332 | _public_ const char* sd_bus_track_contains(sd_bus_track *track, const char *name) { | |
60f067b4 JS |
333 | assert_return(name, NULL); |
334 | ||
8a584da2 MP |
335 | if (!track) /* Let's consider a NULL object equivalent to an empty object */ |
336 | return NULL; | |
337 | ||
60f067b4 JS |
338 | return hashmap_get(track->names, (void*) name) ? name : NULL; |
339 | } | |
340 | ||
341 | _public_ const char* sd_bus_track_first(sd_bus_track *track) { | |
342 | const char *n = NULL; | |
343 | ||
344 | if (!track) | |
345 | return NULL; | |
346 | ||
347 | track->modified = false; | |
5eef597e | 348 | track->iterator = ITERATOR_FIRST; |
60f067b4 | 349 | |
86f210e9 | 350 | hashmap_iterate(track->names, &track->iterator, NULL, (const void**) &n); |
60f067b4 JS |
351 | return n; |
352 | } | |
353 | ||
354 | _public_ const char* sd_bus_track_next(sd_bus_track *track) { | |
355 | const char *n = NULL; | |
356 | ||
357 | if (!track) | |
358 | return NULL; | |
359 | ||
360 | if (track->modified) | |
361 | return NULL; | |
362 | ||
86f210e9 | 363 | hashmap_iterate(track->names, &track->iterator, NULL, (const void**) &n); |
60f067b4 JS |
364 | return n; |
365 | } | |
366 | ||
367 | _public_ int sd_bus_track_add_sender(sd_bus_track *track, sd_bus_message *m) { | |
368 | const char *sender; | |
369 | ||
370 | assert_return(track, -EINVAL); | |
371 | assert_return(m, -EINVAL); | |
372 | ||
8a584da2 MP |
373 | if (sd_bus_message_get_bus(m) != track->bus) |
374 | return -EINVAL; | |
375 | ||
60f067b4 JS |
376 | sender = sd_bus_message_get_sender(m); |
377 | if (!sender) | |
378 | return -EINVAL; | |
379 | ||
380 | return sd_bus_track_add_name(track, sender); | |
381 | } | |
382 | ||
383 | _public_ int sd_bus_track_remove_sender(sd_bus_track *track, sd_bus_message *m) { | |
384 | const char *sender; | |
385 | ||
60f067b4 JS |
386 | assert_return(m, -EINVAL); |
387 | ||
8a584da2 MP |
388 | if (!track) /* Treat a NULL track object as an empty track object */ |
389 | return 0; | |
390 | ||
391 | if (sd_bus_message_get_bus(m) != track->bus) | |
392 | return -EINVAL; | |
393 | ||
60f067b4 JS |
394 | sender = sd_bus_message_get_sender(m); |
395 | if (!sender) | |
396 | return -EINVAL; | |
397 | ||
398 | return sd_bus_track_remove_name(track, sender); | |
399 | } | |
400 | ||
401 | _public_ sd_bus* sd_bus_track_get_bus(sd_bus_track *track) { | |
402 | assert_return(track, NULL); | |
403 | ||
404 | return track->bus; | |
405 | } | |
406 | ||
407 | void bus_track_dispatch(sd_bus_track *track) { | |
408 | int r; | |
409 | ||
410 | assert(track); | |
60f067b4 JS |
411 | assert(track->handler); |
412 | ||
413 | bus_track_remove_from_queue(track); | |
414 | ||
415 | sd_bus_track_ref(track); | |
416 | ||
417 | r = track->handler(track, track->userdata); | |
418 | if (r < 0) | |
f47781d8 | 419 | log_debug_errno(r, "Failed to process track handler: %m"); |
60f067b4 JS |
420 | else if (r == 0) |
421 | bus_track_add_to_queue(track); | |
422 | ||
423 | sd_bus_track_unref(track); | |
424 | } | |
425 | ||
8a584da2 | 426 | void bus_track_close(sd_bus_track *track) { |
8a584da2 MP |
427 | assert(track); |
428 | ||
429 | /* Called whenever our bus connected is closed. If so, and our track object is non-empty, dispatch it | |
430 | * immediately, as we are closing now, but first flush out all names. */ | |
431 | ||
432 | if (!track->in_list) | |
433 | return; /* We already closed this one, don't close it again. */ | |
434 | ||
435 | /* Remember that this one is closed now */ | |
436 | LIST_REMOVE(tracks, track->bus->tracks, track); | |
437 | track->in_list = false; | |
438 | ||
439 | /* If there's no name in this one anyway, we don't have to dispatch */ | |
440 | if (hashmap_isempty(track->names)) | |
441 | return; | |
442 | ||
443 | /* Let's flush out all names */ | |
52ad194e | 444 | hashmap_clear_with_destructor(track->names, track_item_free); |
8a584da2 MP |
445 | |
446 | /* Invoke handler */ | |
447 | if (track->handler) | |
448 | bus_track_dispatch(track); | |
449 | } | |
450 | ||
60f067b4 JS |
451 | _public_ void *sd_bus_track_get_userdata(sd_bus_track *track) { |
452 | assert_return(track, NULL); | |
453 | ||
454 | return track->userdata; | |
455 | } | |
456 | ||
457 | _public_ void *sd_bus_track_set_userdata(sd_bus_track *track, void *userdata) { | |
458 | void *ret; | |
459 | ||
460 | assert_return(track, NULL); | |
461 | ||
462 | ret = track->userdata; | |
463 | track->userdata = userdata; | |
464 | ||
465 | return ret; | |
466 | } | |
8a584da2 MP |
467 | |
468 | _public_ int sd_bus_track_set_recursive(sd_bus_track *track, int b) { | |
469 | assert_return(track, -EINVAL); | |
470 | ||
471 | if (track->recursive == !!b) | |
472 | return 0; | |
473 | ||
474 | if (!hashmap_isempty(track->names)) | |
475 | return -EBUSY; | |
476 | ||
477 | track->recursive = b; | |
478 | return 0; | |
479 | } | |
480 | ||
481 | _public_ int sd_bus_track_get_recursive(sd_bus_track *track) { | |
482 | assert_return(track, -EINVAL); | |
483 | ||
484 | return track->recursive; | |
485 | } | |
486 | ||
487 | _public_ int sd_bus_track_count_sender(sd_bus_track *track, sd_bus_message *m) { | |
488 | const char *sender; | |
489 | ||
490 | assert_return(m, -EINVAL); | |
491 | ||
492 | if (!track) /* Let's consider a NULL object equivalent to an empty object */ | |
493 | return 0; | |
494 | ||
495 | if (sd_bus_message_get_bus(m) != track->bus) | |
496 | return -EINVAL; | |
497 | ||
498 | sender = sd_bus_message_get_sender(m); | |
499 | if (!sender) | |
500 | return -EINVAL; | |
501 | ||
502 | return sd_bus_track_count_name(track, sender); | |
503 | } | |
504 | ||
505 | _public_ int sd_bus_track_count_name(sd_bus_track *track, const char *name) { | |
506 | struct track_item *i; | |
507 | ||
508 | assert_return(service_name_is_valid(name), -EINVAL); | |
509 | ||
510 | if (!track) /* Let's consider a NULL object equivalent to an empty object */ | |
511 | return 0; | |
512 | ||
513 | i = hashmap_get(track->names, name); | |
514 | if (!i) | |
515 | return 0; | |
516 | ||
517 | return i->n_ref; | |
518 | } |