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 * $DragonFly: src/sys/kern/subr_eventhandler.c,v 1.5 2006/09/05 03:48:12 dillon Exp $ 30 */ 31 32 #include <sys/param.h> 33 #include <sys/kernel.h> 34 #include <sys/malloc.h> 35 #include <sys/systm.h> 36 #include <sys/eventhandler.h> 37 38 #include <sys/mplock2.h> 39 40 MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 41 42 /* List of 'slow' lists */ 43 static TAILQ_HEAD(, eventhandler_list) eventhandler_lists = TAILQ_HEAD_INITIALIZER(eventhandler_lists); 44 static struct lwkt_token evlist_token = LWKT_TOKEN_MP_INITIALIZER(evlist_token); 45 46 struct eventhandler_entry_generic 47 { 48 struct eventhandler_entry ee; 49 void (* func)(void); 50 }; 51 52 /* 53 * Insertion is O(n) due to the priority scan, but optimises to O(1) 54 * if all priorities are identical. 55 * 56 * MPSAFE 57 */ 58 eventhandler_tag 59 eventhandler_register(struct eventhandler_list *list, char *name, 60 void *func, void *arg, int priority) 61 { 62 struct eventhandler_entry_generic *eg; 63 struct eventhandler_entry *ep; 64 65 lwkt_gettoken(&evlist_token); 66 67 /* 68 * find/create the list as needed 69 */ 70 while (list == NULL) { 71 list = eventhandler_find_list(name); 72 if (list) 73 break; 74 list = kmalloc(sizeof(struct eventhandler_list) + strlen(name) + 1, 75 M_EVENTHANDLER, M_INTWAIT); 76 if (eventhandler_find_list(name)) { 77 kfree(list, M_EVENTHANDLER); 78 list = NULL; 79 } else { 80 list->el_flags = 0; 81 list->el_name = (char *)list + sizeof(struct eventhandler_list); 82 strcpy(list->el_name, name); 83 TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 84 } 85 } 86 87 if (!(list->el_flags & EHE_INITTED)) { 88 TAILQ_INIT(&list->el_entries); 89 list->el_flags = EHE_INITTED; 90 } 91 92 /* allocate an entry for this handler, populate it */ 93 eg = kmalloc(sizeof(struct eventhandler_entry_generic), 94 M_EVENTHANDLER, M_INTWAIT); 95 eg->func = func; 96 eg->ee.ee_arg = arg; 97 eg->ee.ee_priority = priority; 98 99 /* sort it into the list */ 100 for (ep = TAILQ_FIRST(&list->el_entries); 101 ep != NULL; 102 ep = TAILQ_NEXT(ep, ee_link)) { 103 if (eg->ee.ee_priority < ep->ee_priority) { 104 TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 105 break; 106 } 107 } 108 if (ep == NULL) 109 TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 110 lwkt_reltoken(&evlist_token); 111 112 return(&eg->ee); 113 } 114 115 /* 116 * MPSAFE 117 */ 118 void 119 eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 120 { 121 struct eventhandler_entry *ep = tag; 122 123 lwkt_gettoken(&evlist_token); 124 /* XXX insert diagnostic check here? */ 125 126 if (ep != NULL) { 127 /* remove just this entry */ 128 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 129 kfree(ep, M_EVENTHANDLER); 130 } else { 131 /* remove entire list */ 132 while (!TAILQ_EMPTY(&list->el_entries)) { 133 ep = TAILQ_FIRST(&list->el_entries); 134 TAILQ_REMOVE(&list->el_entries, ep, ee_link); 135 kfree(ep, M_EVENTHANDLER); 136 } 137 } 138 lwkt_reltoken(&evlist_token); 139 } 140 141 /* 142 * Locate the requested list 143 */ 144 struct eventhandler_list * 145 eventhandler_find_list(char *name) 146 { 147 struct eventhandler_list *list; 148 149 lwkt_gettoken(&evlist_token); 150 for (list = TAILQ_FIRST(&eventhandler_lists); 151 list != NULL; 152 list = TAILQ_NEXT(list, el_link)) { 153 if (!strcmp(name, list->el_name)) 154 break; 155 } 156 lwkt_reltoken(&evlist_token); 157 return(list); 158 } 159