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/systm.h> 33 #include <sys/eventhandler.h> 34 35 MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 36 37 /* List of 'slow' lists */ 38 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists; 39 static int eventhandler_lists_initted = 0; 40 41 struct eventhandler_entry_generic 42 { 43 struct eventhandler_entry ee; 44 void (* func)(void); 45 }; 46 47 /* 48 * Insertion is O(n) due to the priority scan, but optimises to O(1) 49 * if all priorities are identical. 50 */ 51 eventhandler_tag 52 eventhandler_register(struct eventhandler_list *list, char *name, 53 void *func, void *arg, int priority) 54 { 55 struct eventhandler_entry_generic *eg; 56 struct eventhandler_entry *ep; 57 58 /* avoid the need for a SYSINIT just to init the list */ 59 if (!eventhandler_lists_initted) { 60 TAILQ_INIT(&eventhandler_lists); 61 eventhandler_lists_initted = 1; 62 } 63 64 /* Do we need to find/create the (slow) list? */ 65 if (list == NULL) { 66 /* look for a matching, existing list */ 67 list = eventhandler_find_list(name); 68 69 /* Do we need to create the list? */ 70 if (list == NULL) { 71 if ((list = malloc(sizeof(struct eventhandler_list) + strlen(name) + 1, 72 M_EVENTHANDLER, M_NOWAIT)) == NULL) 73 return(NULL); 74 list->el_flags = 0; 75 list->el_name = (char *)list + sizeof(struct eventhandler_list); 76 strcpy(list->el_name, name); 77 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 78 } 79 } 80 if (!(list->el_flags & EHE_INITTED)) { 81 TAILQ_INIT(&list->el_entries); 82 list->el_flags = EHE_INITTED; 83 } 84 85 /* allocate an entry for this handler, populate it */ 86 if ((eg = malloc(sizeof(struct eventhandler_entry_generic), 87 M_EVENTHANDLER, M_NOWAIT)) == NULL) 88 return(NULL); 89 eg->func = func; 90 eg->ee.ee_arg = arg; 91 eg->ee.ee_priority = priority; 92 93 /* sort it into the list */ 94 for (ep = TAILQ_FIRST(&list->el_entries); 95 ep != NULL; 96 ep = TAILQ_NEXT(ep, ee_link)) { 97 if (eg->ee.ee_priority < ep->ee_priority) { 98 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 99 break; 100 } 101 } 102 if (ep == NULL) 103 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 104 return(&eg->ee); 105 } 106 107 void 108 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 109 { 110 struct eventhandler_entry *ep = tag; 111 112 /* XXX insert diagnostic check here? */ 113 if (ep != NULL) { 114 /* remove just this entry */ 115 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 116 free(ep, M_EVENTHANDLER); 117 } else { 118 /* remove entire list */ 119 while (!TAILQ_EMPTY(&list->el_entries)) { 120 ep = TAILQ_FIRST(&list->el_entries); 121 TAILQ_REMOVE(&list->el_entries, list->el_entries.tqh_first, ee_link); 122 free(ep, M_EVENTHANDLER); 123 } 124 } 125 } 126 127 struct eventhandler_list * 128 eventhandler_find_list(char *name) 129 { 130 struct eventhandler_list *list; 131 132 /* scan looking for the requested list */ 133 for (list = TAILQ_FIRST(&eventhandler_lists); 134 list != NULL; 135 list = TAILQ_NEXT(list, el_link)) { 136 if (!strcmp(name, list->el_name)) 137 break; 138 } 139 return(list); 140 } 141