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/systm.h> 35 #include <sys/eventhandler.h> 36 37 static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 38 39 /* List of 'slow' lists */ 40 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists; 41 static int eventhandler_lists_initted = 0; 42 static struct mtx eventhandler_mutex; 43 44 struct eventhandler_entry_generic 45 { 46 struct eventhandler_entry ee; 47 void (* func)(void); 48 }; 49 50 /* 51 * Initialize the eventhandler mutex and list. 52 */ 53 static void 54 eventhandler_init(void *dummy __unused) 55 { 56 TAILQ_INIT(&eventhandler_lists); 57 mtx_init(&eventhandler_mutex, "eventhandler", MTX_DEF | MTX_RECURSE); 58 eventhandler_lists_initted = 1; 59 } 60 SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init, 61 NULL) 62 63 /* 64 * Insertion is O(n) due to the priority scan, but optimises to O(1) 65 * if all priorities are identical. 66 */ 67 eventhandler_tag 68 eventhandler_register(struct eventhandler_list *list, char *name, 69 void *func, void *arg, int priority) 70 { 71 struct eventhandler_entry_generic *eg; 72 struct eventhandler_entry *ep; 73 74 KASSERT(eventhandler_lists_initted, ("eventhandler registered too early")); 75 76 /* lock the eventhandler lists */ 77 mtx_lock(&eventhandler_mutex); 78 79 /* Do we need to find/create the (slow) list? */ 80 if (list == NULL) { 81 /* look for a matching, existing list */ 82 list = eventhandler_find_list(name); 83 84 /* Do we need to create the list? */ 85 if (list == NULL) { 86 if ((list = malloc(sizeof(struct eventhandler_list) + strlen(name) + 1, 87 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 88 mtx_unlock(&eventhandler_mutex); 89 return(NULL); 90 } 91 list->el_flags = 0; 92 list->el_name = (char *)list + sizeof(struct eventhandler_list); 93 strcpy(list->el_name, name); 94 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 95 } 96 } 97 if (!(list->el_flags & EHE_INITTED)) { 98 TAILQ_INIT(&list->el_entries); 99 lockinit(&list->el_lock, PZERO, name, 0, 0); 100 list->el_flags = EHE_INITTED; 101 } 102 103 /* allocate an entry for this handler, populate it */ 104 if ((eg = malloc(sizeof(struct eventhandler_entry_generic), 105 M_EVENTHANDLER, M_NOWAIT)) == NULL) { 106 mtx_unlock(&eventhandler_mutex); 107 return(NULL); 108 } 109 eg->func = func; 110 eg->ee.ee_arg = arg; 111 eg->ee.ee_priority = priority; 112 113 /* sort it into the list */ 114 lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC); 115 for (ep = TAILQ_FIRST(&list->el_entries); 116 ep != NULL; 117 ep = TAILQ_NEXT(ep, ee_link)) { 118 if (eg->ee.ee_priority < ep->ee_priority) { 119 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 120 break; 121 } 122 } 123 if (ep == NULL) 124 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 125 lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC); 126 mtx_unlock(&eventhandler_mutex); 127 return(&eg->ee); 128 } 129 130 void 131 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 132 { 133 struct eventhandler_entry *ep = tag; 134 135 /* XXX insert diagnostic check here? */ 136 lockmgr(&list->el_lock, LK_EXCLUSIVE, NULL, CURPROC); 137 if (ep != NULL) { 138 /* remove just this entry */ 139 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 140 free(ep, M_EVENTHANDLER); 141 } else { 142 /* remove entire list */ 143 while (!TAILQ_EMPTY(&list->el_entries)) { 144 ep = TAILQ_FIRST(&list->el_entries); 145 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 146 free(ep, M_EVENTHANDLER); 147 } 148 } 149 lockmgr(&list->el_lock, LK_RELEASE, NULL, CURPROC); 150 } 151 152 struct eventhandler_list * 153 eventhandler_find_list(char *name) 154 { 155 struct eventhandler_list *list; 156 157 /* scan looking for the requested list */ 158 mtx_lock(&eventhandler_mutex); 159 for (list = TAILQ_FIRST(&eventhandler_lists); 160 list != NULL; 161 list = TAILQ_NEXT(list, el_link)) { 162 if (!strcmp(name, list->el_name)) 163 break; 164 } 165 mtx_unlock(&eventhandler_mutex); 166 167 return(list); 168 } 169 170