1 /*- 2 * Copyright (c) 1999 Michael Smith <msmith@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. 13 * 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 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/kernel.h> 31 #include <sys/lock.h> 32 #include <sys/malloc.h> 33 #include <sys/mutex.h> 34 #include <sys/proc.h> 35 #include <sys/systm.h> 36 #include <sys/eventhandler.h> 37 38 static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 39 40 /* List of 'slow' lists */ 41 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists; 42 static int eventhandler_lists_initted = 0; 43 static struct mtx eventhandler_mutex; 44 45 struct eventhandler_entry_generic 46 { 47 struct eventhandler_entry ee; 48 void (* func)(void); 49 }; 50 51 /* 52 * Initialize the eventhandler mutex and list. 53 */ 54 static void 55 eventhandler_init(void *dummy __unused) 56 { 57 TAILQ_INIT(&eventhandler_lists); 58 mtx_init(&eventhandler_mutex, "eventhandler", MTX_DEF | MTX_RECURSE); 59 eventhandler_lists_initted = 1; 60 } 61 SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init, 62 NULL) 63 64 /* 65 * Insertion is O(n) due to the priority scan, but optimises to O(1) 66 * if all priorities are identical. 67 */ 68 eventhandler_tag 69 eventhandler_register(struct eventhandler_list *list, char *name, 70 void *func, void *arg, int priority) 71 { 72 struct eventhandler_entry_generic *eg; 73 struct eventhandler_entry *ep; 74 75 KASSERT(eventhandler_lists_initted, ("eventhandler registered too early")); 76 77 /* lock the eventhandler lists */ 78 mtx_lock(&eventhandler_mutex); 79 80 /* Do we need to find/create the (slow) list? */ 81 if (list == NULL) { 82 /* look for a matching, existing list */ 83 list = eventhandler_find_list(name); 84 85 /* Do we need to create the list? */ 86 if (list == NULL) { 87 if ((list = malloc(sizeof(struct eventhandler_list) + strlen(name) + 1, 88 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 89 mtx_unlock(&eventhandler_mutex); 90 return(NULL); 91 } 92 list->el_flags = 0; 93 bzero(&list->el_lock, sizeof(list->el_lock)); 94 list->el_name = (char *)list + sizeof(struct eventhandler_list); 95 strcpy(list->el_name, name); 96 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 97 } 98 } 99 if (!(list->el_flags & EHE_INITTED)) { 100 TAILQ_INIT(&list->el_entries); 101 sx_init(&list->el_lock, name); 102 list->el_flags = EHE_INITTED; 103 } 104 105 /* allocate an entry for this handler, populate it */ 106 if ((eg = malloc(sizeof(struct eventhandler_entry_generic), 107 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 108 mtx_unlock(&eventhandler_mutex); 109 return(NULL); 110 } 111 eg->func = func; 112 eg->ee.ee_arg = arg; 113 eg->ee.ee_priority = priority; 114 115 /* sort it into the list */ 116 EHE_LOCK(list); 117 for (ep = TAILQ_FIRST(&list->el_entries); 118 ep != NULL; 119 ep = TAILQ_NEXT(ep, ee_link)) { 120 if (eg->ee.ee_priority < ep->ee_priority) { 121 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 122 break; 123 } 124 } 125 if (ep == NULL) 126 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 127 EHE_UNLOCK(list); 128 mtx_unlock(&eventhandler_mutex); 129 return(&eg->ee); 130 } 131 132 void 133 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 134 { 135 struct eventhandler_entry *ep = tag; 136 137 /* XXX insert diagnostic check here? */ 138 EHE_LOCK(list); 139 if (ep != NULL) { 140 /* remove just this entry */ 141 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 142 free(ep, M_EVENTHANDLER); 143 } else { 144 /* remove entire list */ 145 while (!TAILQ_EMPTY(&list->el_entries)) { 146 ep = TAILQ_FIRST(&list->el_entries); 147 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 148 free(ep, M_EVENTHANDLER); 149 } 150 } 151 EHE_UNLOCK(list); 152 } 153 154 struct eventhandler_list * 155 eventhandler_find_list(char *name) 156 { 157 struct eventhandler_list *list; 158 159 if (!eventhandler_lists_initted) 160 return(NULL); 161 162 /* scan looking for the requested list */ 163 mtx_lock(&eventhandler_mutex); 164 for (list = TAILQ_FIRST(&eventhandler_lists); 165 list != NULL; 166 list = TAILQ_NEXT(list, el_link)) { 167 if (!strcmp(name, list->el_name)) 168 break; 169 } 170 mtx_unlock(&eventhandler_mutex); 171 172 return(list); 173 } 174 175