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1 /*
2  *
3  *  D-Bus helper library
4  *
5  *  Copyright (C) 2004-2009  Marcel Holtmann <marcel@holtmann.org>
6  *
7  *
8  *  This program is free software; you can redistribute it and/or modify
9  *  it under the terms of the GNU General Public License as published by
10  *  the Free Software Foundation; either version 2 of the License, or
11  *  (at your option) any later version.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to the Free Software
20  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
21  *
22  */
23 
24 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27 
28 #include <stdio.h>
29 #include <string.h>
30 
31 #include <glib.h>
32 #include <dbus/dbus.h>
33 
34 #include "gdbus.h"
35 
36 #define info(fmt...)
37 #define error(fmt...)
38 #define debug(fmt...)
39 
40 static DBusHandlerResult name_exit_filter(DBusConnection *connection,
41 					DBusMessage *message, void *user_data);
42 
43 static guint listener_id = 0;
44 static GSList *name_listeners = NULL;
45 
46 struct name_callback {
47 	GDBusWatchFunction conn_func;
48 	GDBusWatchFunction disc_func;
49 	void *user_data;
50 	guint id;
51 };
52 
53 struct name_data {
54 	DBusConnection *connection;
55 	char *name;
56 	GSList *callbacks;
57 	GSList *processed;
58 	gboolean lock;
59 };
60 
name_data_find(DBusConnection * connection,const char * name)61 static struct name_data *name_data_find(DBusConnection *connection,
62 							const char *name)
63 {
64 	GSList *current;
65 
66 	for (current = name_listeners;
67 			current != NULL; current = current->next) {
68 		struct name_data *data = current->data;
69 
70 		if (connection != data->connection)
71 			continue;
72 
73 		if (name == NULL || g_str_equal(name, data->name))
74 			return data;
75 	}
76 
77 	return NULL;
78 }
79 
name_callback_find(GSList * callbacks,guint id)80 static struct name_callback *name_callback_find(GSList *callbacks, guint id)
81 {
82 	GSList *current;
83 
84 	for (current = callbacks; current != NULL; current = current->next) {
85 		struct name_callback *cb = current->data;
86 		if (cb->id == id)
87 			return cb;
88 	}
89 
90 	return NULL;
91 }
92 
name_data_call_and_free(struct name_data * data)93 static void name_data_call_and_free(struct name_data *data)
94 {
95 	GSList *l;
96 
97 	for (l = data->callbacks; l != NULL; l = l->next) {
98 		struct name_callback *cb = l->data;
99 		if (cb->disc_func)
100 			cb->disc_func(data->connection, cb->user_data);
101 		g_free(cb);
102 	}
103 
104 	g_slist_free(data->callbacks);
105 	g_free(data->name);
106 	g_free(data);
107 }
108 
name_data_free(struct name_data * data)109 static void name_data_free(struct name_data *data)
110 {
111 	GSList *l;
112 
113 	for (l = data->callbacks; l != NULL; l = l->next)
114 		g_free(l->data);
115 
116 	g_slist_free(data->callbacks);
117 	g_free(data->name);
118 	g_free(data);
119 }
120 
name_data_add(DBusConnection * connection,const char * name,GDBusWatchFunction connect,GDBusWatchFunction disconnect,void * user_data,guint id)121 static int name_data_add(DBusConnection *connection, const char *name,
122 						GDBusWatchFunction connect,
123 						GDBusWatchFunction disconnect,
124 						void *user_data, guint id)
125 {
126 	int first = 1;
127 	struct name_data *data = NULL;
128 	struct name_callback *cb = NULL;
129 
130 	cb = g_new(struct name_callback, 1);
131 
132 	cb->conn_func = connect;
133 	cb->disc_func = disconnect;
134 	cb->user_data = user_data;
135 	cb->id = id;
136 
137 	data = name_data_find(connection, name);
138 	if (data) {
139 		first = 0;
140 		goto done;
141 	}
142 
143 	data = g_new0(struct name_data, 1);
144 
145 	data->connection = connection;
146 	data->name = g_strdup(name);
147 
148 	name_listeners = g_slist_append(name_listeners, data);
149 
150 done:
151 	if (data->lock)
152 		data->processed = g_slist_append(data->processed, cb);
153 	else
154 		data->callbacks = g_slist_append(data->callbacks, cb);
155 
156 	return first;
157 }
158 
name_data_remove(DBusConnection * connection,const char * name,guint id)159 static void name_data_remove(DBusConnection *connection,
160 					const char *name, guint id)
161 {
162 	struct name_data *data;
163 	struct name_callback *cb = NULL;
164 
165 	data = name_data_find(connection, name);
166 	if (!data)
167 		return;
168 
169 	cb = name_callback_find(data->callbacks, id);
170 	if (cb) {
171 		data->callbacks = g_slist_remove(data->callbacks, cb);
172 		g_free(cb);
173 	}
174 
175 	if (data->callbacks)
176 		return;
177 
178 	name_listeners = g_slist_remove(name_listeners, data);
179 	name_data_free(data);
180 
181 	/* Remove filter if there are no listeners left for the connection */
182 	data = name_data_find(connection, NULL);
183 	if (!data)
184 		dbus_connection_remove_filter(connection,
185 						name_exit_filter,
186 						NULL);
187 }
188 
add_match(DBusConnection * connection,const char * name)189 static gboolean add_match(DBusConnection *connection, const char *name)
190 {
191 	DBusError err;
192 	char match_string[128];
193 
194 	snprintf(match_string, sizeof(match_string),
195 			"interface=%s,member=NameOwnerChanged,arg0=%s",
196 			DBUS_INTERFACE_DBUS, name);
197 
198 	dbus_error_init(&err);
199 
200 	dbus_bus_add_match(connection, match_string, &err);
201 
202 	if (dbus_error_is_set(&err)) {
203 		error("Adding match rule \"%s\" failed: %s", match_string,
204 				err.message);
205 		dbus_error_free(&err);
206 		return FALSE;
207 	}
208 
209 	return TRUE;
210 }
211 
remove_match(DBusConnection * connection,const char * name)212 static gboolean remove_match(DBusConnection *connection, const char *name)
213 {
214 	DBusError err;
215 	char match_string[128];
216 
217 	snprintf(match_string, sizeof(match_string),
218 			"interface=%s,member=NameOwnerChanged,arg0=%s",
219 			DBUS_INTERFACE_DBUS, name);
220 
221 	dbus_error_init(&err);
222 
223 	dbus_bus_remove_match(connection, match_string, &err);
224 
225 	if (dbus_error_is_set(&err)) {
226 		error("Removing owner match rule for %s failed: %s",
227 				name, err.message);
228 		dbus_error_free(&err);
229 		return FALSE;
230 	}
231 
232 	return TRUE;
233 }
234 
name_exit_filter(DBusConnection * connection,DBusMessage * message,void * user_data)235 static DBusHandlerResult name_exit_filter(DBusConnection *connection,
236 					DBusMessage *message, void *user_data)
237 {
238 	struct name_data *data;
239 	struct name_callback *cb;
240 	char *name, *old, *new;
241 
242 	if (!dbus_message_is_signal(message, DBUS_INTERFACE_DBUS,
243 							"NameOwnerChanged"))
244 		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
245 
246 	if (!dbus_message_get_args(message, NULL,
247 				DBUS_TYPE_STRING, &name,
248 				DBUS_TYPE_STRING, &old,
249 				DBUS_TYPE_STRING, &new,
250 				DBUS_TYPE_INVALID)) {
251 		error("Invalid arguments for NameOwnerChanged signal");
252 		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
253 	}
254 
255 	data = name_data_find(connection, name);
256 	if (!data) {
257 		error("Got NameOwnerChanged signal for %s which has no listeners", name);
258 		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
259 	}
260 
261 	data->lock = TRUE;
262 
263 	while (data->callbacks) {
264 		cb = data->callbacks->data;
265 
266 		if (*new == '\0') {
267 			if (cb->disc_func)
268 				cb->disc_func(connection, cb->user_data);
269 		} else {
270 			if (cb->conn_func)
271 				cb->conn_func(connection, cb->user_data);
272 		}
273 
274 		/* Check if the watch was removed/freed by the callback
275 		 * function */
276 		if (!g_slist_find(data->callbacks, cb))
277 			continue;
278 
279 		data->callbacks = g_slist_remove(data->callbacks, cb);
280 
281 		if (!cb->conn_func || !cb->disc_func) {
282 			g_free(cb);
283 			continue;
284 		}
285 
286 		data->processed = g_slist_append(data->processed, cb);
287 	}
288 
289 	data->callbacks = data->processed;
290 	data->processed = NULL;
291 	data->lock = FALSE;
292 
293 	if (data->callbacks)
294 		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
295 
296 	name_listeners = g_slist_remove(name_listeners, data);
297 	name_data_free(data);
298 
299 	/* Remove filter if there no listener left for the connection */
300 	data = name_data_find(connection, NULL);
301 	if (!data)
302 		dbus_connection_remove_filter(connection, name_exit_filter,
303 						NULL);
304 
305 	remove_match(connection, name);
306 
307 	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
308 }
309 
g_dbus_add_service_watch(DBusConnection * connection,const char * name,GDBusWatchFunction connect,GDBusWatchFunction disconnect,void * user_data,GDBusDestroyFunction destroy)310 guint g_dbus_add_service_watch(DBusConnection *connection, const char *name,
311 				GDBusWatchFunction connect,
312 				GDBusWatchFunction disconnect,
313 				void *user_data, GDBusDestroyFunction destroy)
314 {
315 	int first;
316 
317 	if (!name_data_find(connection, NULL)) {
318 		if (!dbus_connection_add_filter(connection,
319 					name_exit_filter, NULL, NULL)) {
320 			error("dbus_connection_add_filter() failed");
321 			return 0;
322 		}
323 	}
324 
325 	listener_id++;
326 	first = name_data_add(connection, name, connect, disconnect,
327 						user_data, listener_id);
328 	/* The filter is already added if this is not the first callback
329 	 * registration for the name */
330 	if (!first)
331 		return listener_id;
332 
333 	if (name) {
334 		debug("name_listener_add(%s)", name);
335 
336 		if (!add_match(connection, name)) {
337 			name_data_remove(connection, name, listener_id);
338 			return 0;
339 		}
340 	}
341 
342 	return listener_id;
343 }
344 
g_dbus_add_disconnect_watch(DBusConnection * connection,const char * name,GDBusWatchFunction func,void * user_data,GDBusDestroyFunction destroy)345 guint g_dbus_add_disconnect_watch(DBusConnection *connection, const char *name,
346 				GDBusWatchFunction func,
347 				void *user_data, GDBusDestroyFunction destroy)
348 {
349 	return g_dbus_add_service_watch(connection, name, NULL, func,
350 							user_data, destroy);
351 }
352 
g_dbus_add_signal_watch(DBusConnection * connection,const char * rule,GDBusSignalFunction function,void * user_data,GDBusDestroyFunction destroy)353 guint g_dbus_add_signal_watch(DBusConnection *connection,
354 				const char *rule, GDBusSignalFunction function,
355 				void *user_data, GDBusDestroyFunction destroy)
356 {
357 	return 0;
358 }
359 
g_dbus_remove_watch(DBusConnection * connection,guint id)360 gboolean g_dbus_remove_watch(DBusConnection *connection, guint id)
361 {
362 	struct name_data *data;
363 	struct name_callback *cb;
364 	GSList *ldata, *lcb;
365 
366 	if (id == 0)
367 		return FALSE;
368 
369 	for (ldata = name_listeners; ldata; ldata = ldata->next) {
370 		data = ldata->data;
371 		for (lcb = data->callbacks; lcb; lcb = lcb->next) {
372 			cb = lcb->data;
373 			if (cb->id == id)
374 				goto remove;
375 		}
376 		for (lcb = data->processed; lcb; lcb = lcb->next) {
377 			cb = lcb->data;
378 			if (cb->id == id)
379 				goto remove;
380 		}
381 	}
382 
383 	return FALSE;
384 
385 remove:
386 	data->callbacks = g_slist_remove(data->callbacks, cb);
387 	data->processed = g_slist_remove(data->processed, cb);
388 	g_free(cb);
389 
390 	/* Don't remove the filter if other callbacks exist or data is lock
391 	 * processing callbacks */
392 	if (data->callbacks || data->lock)
393 		return TRUE;
394 
395 	if (data->name) {
396 		if (!remove_match(data->connection, data->name))
397 			return FALSE;
398 	}
399 
400 	name_listeners = g_slist_remove(name_listeners, data);
401 	name_data_free(data);
402 
403 	/* Remove filter if there are no listeners left for the connection */
404 	data = name_data_find(connection, NULL);
405 	if (!data)
406 		dbus_connection_remove_filter(connection, name_exit_filter,
407 						NULL);
408 
409 	return TRUE;
410 }
411 
g_dbus_remove_all_watches(DBusConnection * connection)412 void g_dbus_remove_all_watches(DBusConnection *connection)
413 {
414 	struct name_data *data;
415 
416 	while ((data = name_data_find(connection, NULL))) {
417 		name_listeners = g_slist_remove(name_listeners, data);
418 		name_data_call_and_free(data);
419 	}
420 
421 	dbus_connection_remove_filter(connection, name_exit_filter, NULL);
422 }
423