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/malloc.h> 32 #include <sys/mutex.h> 33 #include <sys/systm.h> 34 #include <sys/eventhandler.h> 35 36 static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 37 38 /* List of 'slow' lists */ 39 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists; 40 static int eventhandler_lists_initted = 0; 41 static struct mtx eventhandler_mutex; 42 43 struct eventhandler_entry_generic 44 { 45 struct eventhandler_entry ee; 46 void (* func)(void); 47 }; 48 49 /* 50 * Initialize the eventhandler mutex and list. 51 */ 52 static void 53 eventhandler_init(void *dummy __unused) 54 { 55 TAILQ_INIT(&eventhandler_lists); 56 mtx_init(&eventhandler_mutex, "eventhandler", MTX_DEF | MTX_RECURSE); 57 eventhandler_lists_initted = 1; 58 } 59 SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init, 60 NULL) 61 62 /* 63 * Insertion is O(n) due to the priority scan, but optimises to O(1) 64 * if all priorities are identical. 65 */ 66 eventhandler_tag 67 eventhandler_register(struct eventhandler_list *list, char *name, 68 void *func, void *arg, int priority) 69 { 70 struct eventhandler_entry_generic *eg; 71 struct eventhandler_entry *ep; 72 73 KASSERT(eventhandler_lists_initted, ("eventhandler registered too early")); 74 75 /* lock the eventhandler lists */ 76 mtx_lock(&eventhandler_mutex); 77 78 /* Do we need to find/create the (slow) list? */ 79 if (list == NULL) { 80 /* look for a matching, existing list */ 81 list = eventhandler_find_list(name); 82 83 /* Do we need to create the list? */ 84 if (list == NULL) { 85 if ((list = malloc(sizeof(struct eventhandler_list) + strlen(name) + 1, 86 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 87 mtx_unlock(&eventhandler_mutex); 88 return(NULL); 89 } 90 list->el_flags = 0; 91 list->el_name = (char *)list + sizeof(struct eventhandler_list); 92 strcpy(list->el_name, name); 93 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 94 } 95 } 96 if (!(list->el_flags & EHE_INITTED)) { 97 TAILQ_INIT(&list->el_entries); 98 lockinit(&list->el_lock, PZERO, name, 0, 0); 99 list->el_flags = EHE_INITTED; 100 } 101 102 /* allocate an entry for this handler, populate it */ 103 if ((eg = malloc(sizeof(struct eventhandler_entry_generic), 104 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 105 mtx_unlock(&eventhandler_mutex); 106 return(NULL); 107 } 108 eg->func = func; 109 eg->ee.ee_arg = arg; 110 eg->ee.ee_priority = priority; 111 112 /* sort it into the list */ 113 lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC); 114 for (ep = TAILQ_FIRST(&list->el_entries); 115 ep != NULL; 116 ep = TAILQ_NEXT(ep, ee_link)) { 117 if (eg->ee.ee_priority < ep->ee_priority) { 118 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 119 break; 120 } 121 } 122 if (ep == NULL) 123 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 124 lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC); 125 mtx_unlock(&eventhandler_mutex); 126 return(&eg->ee); 127 } 128 129 void 130 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 131 { 132 struct eventhandler_entry *ep = tag; 133 134 /* XXX insert diagnostic check here? */ 135 lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC); 136 if (ep != NULL) { 137 /* remove just this entry */ 138 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 139 free(ep, M_EVENTHANDLER); 140 } else { 141 /* remove entire list */ 142 while (!TAILQ_EMPTY(&list->el_entries)) { 143 ep = TAILQ_FIRST(&list->el_entries); 144 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 145 free(ep, M_EVENTHANDLER); 146 } 147 } 148 lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC); 149 } 150 151 struct eventhandler_list * 152 eventhandler_find_list(char *name) 153 { 154 struct eventhandler_list *list; 155 156 /* scan looking for the requested list */ 157 mtx_lock(&eventhandler_mutex); 158 for (list = TAILQ_FIRST(&eventhandler_lists); 159 list != NULL; 160 list = TAILQ_NEXT(list, el_link)) { 161 if (!strcmp(name, list->el_name)) 162 break; 163 } 164 mtx_unlock(&eventhandler_mutex); 165 166 return(list); 167 } 168 169