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