1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1999 Michael Smith <msmith@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD: src/sys/kern/subr_eventhandler.c,v 1.3 1999/11/16 16:28:57 phk Exp $ 29 */ 30 31 #include <sys/param.h> 32 #include <sys/kernel.h> 33 #include <sys/malloc.h> 34 #include <sys/systm.h> 35 #include <sys/eventhandler.h> 36 37 MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 38 39 /* List of 'slow' lists */ 40 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists = TAILQ_HEAD_INITIALIZER(eventhandler_lists); 41 static struct lwkt_token evlist_token = LWKT_TOKEN_INITIALIZER(evlist_token); 42 43 struct eventhandler_entry_generic 44 { 45 struct eventhandler_entry ee; 46 void (* func)(void); 47 }; 48 49 /* 50 * Insertion is O(n) due to the priority scan, but optimises to O(1) 51 * if all priorities are identical. 52 * 53 * MPSAFE 54 */ 55 eventhandler_tag 56 eventhandler_register(struct eventhandler_list *list, const char *name, 57 void *func, void *arg, int priority) 58 { 59 struct eventhandler_entry_generic *eg; 60 struct eventhandler_entry *ep; 61 62 lwkt_gettoken(&evlist_token); 63 64 /* 65 * find/create the list as needed 66 */ 67 while (list == NULL) { 68 list = eventhandler_find_list(name); 69 if (list) 70 break; 71 list = kmalloc(sizeof(struct eventhandler_list) + strlen(name) + 1, 72 M_EVENTHANDLER, M_INTWAIT); 73 if (eventhandler_find_list(name)) { 74 kfree(list, M_EVENTHANDLER); 75 list = NULL; 76 } else { 77 list->el_flags = 0; 78 list->el_name = (char *)list + sizeof(struct eventhandler_list); 79 strcpy(list->el_name, name); 80 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 81 } 82 } 83 84 if (!(list->el_flags & EHE_INITTED)) { 85 TAILQ_INIT(&list->el_entries); 86 list->el_flags = EHE_INITTED; 87 } 88 89 /* allocate an entry for this handler, populate it */ 90 eg = kmalloc(sizeof(struct eventhandler_entry_generic), 91 M_EVENTHANDLER, M_INTWAIT); 92 eg->func = func; 93 eg->ee.ee_arg = arg; 94 eg->ee.ee_priority = priority; 95 96 /* sort it into the list */ 97 for (ep = TAILQ_FIRST(&list->el_entries); 98 ep != NULL; 99 ep = TAILQ_NEXT(ep, ee_link)) { 100 if (eg->ee.ee_priority < ep->ee_priority) { 101 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 102 break; 103 } 104 } 105 if (ep == NULL) 106 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 107 lwkt_reltoken(&evlist_token); 108 109 return(&eg->ee); 110 } 111 112 /* 113 * MPSAFE 114 */ 115 void 116 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 117 { 118 struct eventhandler_entry *ep = tag; 119 120 lwkt_gettoken(&evlist_token); 121 /* XXX insert diagnostic check here? */ 122 123 if (ep != NULL) { 124 /* remove just this entry */ 125 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 126 kfree(ep, M_EVENTHANDLER); 127 } else { 128 /* remove entire list */ 129 while (!TAILQ_EMPTY(&list->el_entries)) { 130 ep = TAILQ_FIRST(&list->el_entries); 131 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 132 kfree(ep, M_EVENTHANDLER); 133 } 134 } 135 lwkt_reltoken(&evlist_token); 136 } 137 138 /* 139 * Locate the requested list 140 */ 141 struct eventhandler_list * 142 eventhandler_find_list(const char *name) 143 { 144 struct eventhandler_list *list; 145 146 lwkt_gettoken(&evlist_token); 147 for (list = TAILQ_FIRST(&eventhandler_lists); 148 list != NULL; 149 list = TAILQ_NEXT(list, el_link)) { 150 if (!strcmp(name, list->el_name)) 151 break; 152 } 153 lwkt_reltoken(&evlist_token); 154 return(list); 155 } 156