2 * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/kernel.h>
33 #include <sys/malloc.h>
34 #include <sys/mutex.h>
36 #include <sys/systm.h>
37 #include <sys/eventhandler.h>
39 static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records");
41 /* List of all eventhandler lists */
42 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists;
43 static int eventhandler_lists_initted = 0;
44 static struct mtx eventhandler_mutex;
46 struct eventhandler_entry_generic
48 struct eventhandler_entry ee;
52 static struct eventhandler_list *_eventhandler_find_list(const char *name);
55 * Initialize the eventhandler mutex and list.
58 eventhandler_init(void *dummy __unused)
60 TAILQ_INIT(&eventhandler_lists);
61 mtx_init(&eventhandler_mutex, "eventhandler", NULL, MTX_DEF);
62 atomic_store_rel_int(&eventhandler_lists_initted, 1);
64 SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init,
67 static struct eventhandler_list *
68 eventhandler_find_or_create_list(const char *name)
70 struct eventhandler_list *list, *new_list;
72 /* look for a matching, existing list */
73 list = _eventhandler_find_list(name);
75 /* Do we need to create the list? */
77 mtx_unlock(&eventhandler_mutex);
79 new_list = malloc(sizeof(*new_list) + strlen(name) + 1,
80 M_EVENTHANDLER, M_WAITOK | M_ZERO);
82 /* If someone else created it already, then use that one. */
83 mtx_lock(&eventhandler_mutex);
84 list = _eventhandler_find_list(name);
86 free(new_list, M_EVENTHANDLER);
88 CTR2(KTR_EVH, "%s: creating list \"%s\"", __func__, name);
90 TAILQ_INIT(&list->el_entries);
91 list->el_name = (char *)(list + 1);
92 strcpy(list->el_name, name);
93 mtx_init(&list->el_lock, list->el_name, "eventhandler list",
95 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link);
102 * Insertion is O(n) due to the priority scan, but optimises to O(1)
103 * if all priorities are identical.
105 static eventhandler_tag
106 eventhandler_register_internal(struct eventhandler_list *list,
107 const char *name, eventhandler_tag epn)
109 struct eventhandler_entry *ep;
111 KASSERT(eventhandler_lists_initted, ("eventhandler registered too early"));
112 KASSERT(epn != NULL, ("%s: cannot register NULL event", __func__));
114 /* Do we need to find/create the list? */
116 mtx_lock(&eventhandler_mutex);
117 list = eventhandler_find_or_create_list(name);
118 mtx_unlock(&eventhandler_mutex);
121 KASSERT(epn->ee_priority != EHE_DEAD_PRIORITY,
122 ("%s: handler for %s registered with dead priority", __func__, name));
124 /* sort it into the list */
125 CTR4(KTR_EVH, "%s: adding item %p (function %p) to \"%s\"", __func__, epn,
126 ((struct eventhandler_entry_generic *)epn)->func, name);
128 TAILQ_FOREACH(ep, &list->el_entries, ee_link) {
129 if (ep->ee_priority != EHE_DEAD_PRIORITY &&
130 epn->ee_priority < ep->ee_priority) {
131 TAILQ_INSERT_BEFORE(ep, epn, ee_link);
136 TAILQ_INSERT_TAIL(&list->el_entries, epn, ee_link);
142 eventhandler_register(struct eventhandler_list *list, const char *name,
143 void *func, void *arg, int priority)
145 struct eventhandler_entry_generic *eg;
147 /* allocate an entry for this handler, populate it */
148 eg = malloc(sizeof(struct eventhandler_entry_generic), M_EVENTHANDLER,
152 eg->ee.ee_priority = priority;
154 return (eventhandler_register_internal(list, name, &eg->ee));
158 struct eventhandler_entry_generic_vimage
160 struct eventhandler_entry ee;
161 vimage_iterator_func_t func; /* Vimage iterator function. */
162 struct eventhandler_entry_vimage v_ee; /* Original func, arg. */
166 vimage_eventhandler_register(struct eventhandler_list *list, const char *name,
167 void *func, void *arg, int priority, vimage_iterator_func_t iterfunc)
169 struct eventhandler_entry_generic_vimage *eg;
171 /* allocate an entry for this handler, populate it */
172 eg = malloc(sizeof(struct eventhandler_entry_generic_vimage),
173 M_EVENTHANDLER, M_WAITOK | M_ZERO);
175 eg->v_ee.func = func;
176 eg->v_ee.ee_arg = arg;
177 eg->ee.ee_arg = &eg->v_ee;
178 eg->ee.ee_priority = priority;
180 return (eventhandler_register_internal(list, name, &eg->ee));
185 _eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag,
188 struct eventhandler_entry *ep = tag;
190 EHL_LOCK_ASSERT(list, MA_OWNED);
192 /* remove just this entry */
193 if (list->el_runcount == 0) {
194 CTR3(KTR_EVH, "%s: removing item %p from \"%s\"", __func__, ep,
196 TAILQ_REMOVE(&list->el_entries, ep, ee_link);
197 free(ep, M_EVENTHANDLER);
199 CTR3(KTR_EVH, "%s: marking item %p from \"%s\" as dead", __func__,
201 ep->ee_priority = EHE_DEAD_PRIORITY;
204 /* remove entire list */
205 if (list->el_runcount == 0) {
206 CTR2(KTR_EVH, "%s: removing all items from \"%s\"", __func__,
208 while (!TAILQ_EMPTY(&list->el_entries)) {
209 ep = TAILQ_FIRST(&list->el_entries);
210 TAILQ_REMOVE(&list->el_entries, ep, ee_link);
211 free(ep, M_EVENTHANDLER);
214 CTR2(KTR_EVH, "%s: marking all items from \"%s\" as dead",
215 __func__, list->el_name);
216 TAILQ_FOREACH(ep, &list->el_entries, ee_link)
217 ep->ee_priority = EHE_DEAD_PRIORITY;
220 while (wait && list->el_runcount > 0)
221 mtx_sleep(list, &list->el_lock, 0, "evhrm", 0);
226 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag)
229 _eventhandler_deregister(list, tag, true);
233 eventhandler_deregister_nowait(struct eventhandler_list *list,
234 eventhandler_tag tag)
237 _eventhandler_deregister(list, tag, false);
241 * Internal version for use when eventhandler list is already locked.
243 static struct eventhandler_list *
244 _eventhandler_find_list(const char *name)
246 struct eventhandler_list *list;
248 mtx_assert(&eventhandler_mutex, MA_OWNED);
249 TAILQ_FOREACH(list, &eventhandler_lists, el_link) {
250 if (!strcmp(name, list->el_name))
257 * Lookup a "slow" list by name. Returns with the list locked.
259 struct eventhandler_list *
260 eventhandler_find_list(const char *name)
262 struct eventhandler_list *list;
264 if (!eventhandler_lists_initted)
267 /* scan looking for the requested list */
268 mtx_lock(&eventhandler_mutex);
269 list = _eventhandler_find_list(name);
272 mtx_unlock(&eventhandler_mutex);
278 * Prune "dead" entries from an eventhandler list.
281 eventhandler_prune_list(struct eventhandler_list *list)
283 struct eventhandler_entry *ep, *en;
286 CTR2(KTR_EVH, "%s: pruning list \"%s\"", __func__, list->el_name);
287 EHL_LOCK_ASSERT(list, MA_OWNED);
288 TAILQ_FOREACH_SAFE(ep, &list->el_entries, ee_link, en) {
289 if (ep->ee_priority == EHE_DEAD_PRIORITY) {
290 TAILQ_REMOVE(&list->el_entries, ep, ee_link);
291 free(ep, M_EVENTHANDLER);
300 * Create (or get the existing) list so the pointer can be stored by
301 * EVENTHANDLER_LIST_DEFINE.
303 struct eventhandler_list *
304 eventhandler_create_list(const char *name)
306 struct eventhandler_list *list;
308 KASSERT(eventhandler_lists_initted,
309 ("eventhandler list created too early"));
311 mtx_lock(&eventhandler_mutex);
312 list = eventhandler_find_or_create_list(name);
313 mtx_unlock(&eventhandler_mutex);