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 list->el_name = (char *)list + sizeof(struct eventhandler_list); 94 strcpy(list->el_name, name); 95 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 96 } 97 } 98 if (!(list->el_flags & EHE_INITTED)) { 99 TAILQ_INIT(&list->el_entries); 100 lockinit(&list->el_lock, PZERO, name, 0, 0); 101 list->el_flags = EHE_INITTED; 102 } 103 104 /* allocate an entry for this handler, populate it */ 105 if ((eg = malloc(sizeof(struct eventhandler_entry_generic), 106 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 107 mtx_unlock(&eventhandler_mutex); 108 return(NULL); 109 } 110 eg->func = func; 111 eg->ee.ee_arg = arg; 112 eg->ee.ee_priority = priority; 113 114 /* sort it into the list */ 115 lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC); 116 for (ep = TAILQ_FIRST(&list->el_entries); 117 ep != NULL; 118 ep = TAILQ_NEXT(ep, ee_link)) { 119 if (eg->ee.ee_priority < ep->ee_priority) { 120 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 121 break; 122 } 123 } 124 if (ep == NULL) 125 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 126 lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC); 127 mtx_unlock(&eventhandler_mutex); 128 return(&eg->ee); 129 } 130 131 void 132 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 133 { 134 struct eventhandler_entry *ep = tag; 135 136 /* XXX insert diagnostic check here? */ 137 lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC); 138 if (ep != NULL) { 139 /* remove just this entry */ 140 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 141 free(ep, M_EVENTHANDLER); 142 } else { 143 /* remove entire list */ 144 while (!TAILQ_EMPTY(&list->el_entries)) { 145 ep = TAILQ_FIRST(&list->el_entries); 146 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 147 free(ep, M_EVENTHANDLER); 148 } 149 } 150 lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC); 151 } 152 153 struct eventhandler_list * 154 eventhandler_find_list(char *name) 155 { 156 struct eventhandler_list *list; 157 158 /* scan looking for the requested list */ 159 mtx_lock(&eventhandler_mutex); 160 for (list = TAILQ_FIRST(&eventhandler_lists); 161 list != NULL; 162 list = TAILQ_NEXT(list, el_link)) { 163 if (!strcmp(name, list->el_name)) 164 break; 165 } 166 mtx_unlock(&eventhandler_mutex); 167 168 return(list); 169 } 170 171