1fcb893a8SMike Smith /*- 2fcb893a8SMike Smith * Copyright (c) 1999 Michael Smith <msmith@freebsd.org> 3fcb893a8SMike Smith * All rights reserved. 4fcb893a8SMike Smith * 5fcb893a8SMike Smith * Redistribution and use in source and binary forms, with or without 6fcb893a8SMike Smith * modification, are permitted provided that the following conditions 7fcb893a8SMike Smith * are met: 8fcb893a8SMike Smith * 1. Redistributions of source code must retain the above copyright 9fcb893a8SMike Smith * notice, this list of conditions and the following disclaimer. 10fcb893a8SMike Smith * 2. Redistributions in binary form must reproduce the above copyright 11fcb893a8SMike Smith * notice, this list of conditions and the following disclaimer in the 12fcb893a8SMike Smith * documentation and/or other materials provided with the distribution. 13fcb893a8SMike Smith * 14fcb893a8SMike Smith * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15fcb893a8SMike Smith * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16fcb893a8SMike Smith * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17fcb893a8SMike Smith * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18fcb893a8SMike Smith * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19fcb893a8SMike Smith * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20fcb893a8SMike Smith * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21fcb893a8SMike Smith * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22fcb893a8SMike Smith * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23fcb893a8SMike Smith * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24fcb893a8SMike Smith * SUCH DAMAGE. 25fcb893a8SMike Smith */ 26fcb893a8SMike Smith 27677b542eSDavid E. O'Brien #include <sys/cdefs.h> 28677b542eSDavid E. O'Brien __FBSDID("$FreeBSD$"); 29677b542eSDavid E. O'Brien 30fcb893a8SMike Smith #include <sys/param.h> 31fcb893a8SMike Smith #include <sys/kernel.h> 32f34fa851SJohn Baldwin #include <sys/lock.h> 33fcb893a8SMike Smith #include <sys/malloc.h> 3406592dd1SJohn Baldwin #include <sys/mutex.h> 35fb919e4dSMark Murray #include <sys/proc.h> 36fcb893a8SMike Smith #include <sys/systm.h> 37fcb893a8SMike Smith #include <sys/eventhandler.h> 38fcb893a8SMike Smith 39959b7375SPoul-Henning Kamp static MALLOC_DEFINE(M_EVENTHANDLER, "eventhandler", "Event handler records"); 40fcb893a8SMike Smith 41fcb893a8SMike Smith /* List of 'slow' lists */ 42e3975643SJake Burkholder static TAILQ_HEAD(, eventhandler_list) eventhandler_lists; 43fcb893a8SMike Smith static int eventhandler_lists_initted = 0; 44d543796fSJohn Baldwin static struct mtx eventhandler_mutex; 45fcb893a8SMike Smith 46fcb893a8SMike Smith struct eventhandler_entry_generic 47fcb893a8SMike Smith { 48fcb893a8SMike Smith struct eventhandler_entry ee; 49fcb893a8SMike Smith void (* func)(void); 50fcb893a8SMike Smith }; 51fcb893a8SMike Smith 52fdf20233SJoseph Koshy static struct eventhandler_list *_eventhandler_find_list(const char *name); 53ecdf4409SJohn Baldwin 54fcb893a8SMike Smith /* 5506592dd1SJohn Baldwin * Initialize the eventhandler mutex and list. 5606592dd1SJohn Baldwin */ 5706592dd1SJohn Baldwin static void 5806592dd1SJohn Baldwin eventhandler_init(void *dummy __unused) 5906592dd1SJohn Baldwin { 6006592dd1SJohn Baldwin TAILQ_INIT(&eventhandler_lists); 61ecdf4409SJohn Baldwin mtx_init(&eventhandler_mutex, "eventhandler", NULL, MTX_DEF); 62ecdf4409SJohn Baldwin atomic_store_rel_int(&eventhandler_lists_initted, 1); 6306592dd1SJohn Baldwin } 6406592dd1SJohn Baldwin SYSINIT(eventhandlers, SI_SUB_EVENTHANDLER, SI_ORDER_FIRST, eventhandler_init, 65237fdd78SRobert Watson NULL); 6606592dd1SJohn Baldwin 6706592dd1SJohn Baldwin /* 68fcb893a8SMike Smith * Insertion is O(n) due to the priority scan, but optimises to O(1) 69fcb893a8SMike Smith * if all priorities are identical. 70fcb893a8SMike Smith */ 71fcb893a8SMike Smith eventhandler_tag 72fdf20233SJoseph Koshy eventhandler_register(struct eventhandler_list *list, const char *name, 73fcb893a8SMike Smith void *func, void *arg, int priority) 74fcb893a8SMike Smith { 75ecdf4409SJohn Baldwin struct eventhandler_list *new_list; 76fcb893a8SMike Smith struct eventhandler_entry_generic *eg; 77fcb893a8SMike Smith struct eventhandler_entry *ep; 78fcb893a8SMike Smith 7906592dd1SJohn Baldwin KASSERT(eventhandler_lists_initted, ("eventhandler registered too early")); 80fcb893a8SMike Smith 816595c331SMike Smith /* lock the eventhandler lists */ 829ed346baSBosko Milekic mtx_lock(&eventhandler_mutex); 836595c331SMike Smith 84fcb893a8SMike Smith /* Do we need to find/create the (slow) list? */ 85fcb893a8SMike Smith if (list == NULL) { 86fcb893a8SMike Smith /* look for a matching, existing list */ 87ecdf4409SJohn Baldwin list = _eventhandler_find_list(name); 88fcb893a8SMike Smith 89fcb893a8SMike Smith /* Do we need to create the list? */ 90fcb893a8SMike Smith if (list == NULL) { 919ed346baSBosko Milekic mtx_unlock(&eventhandler_mutex); 92ecdf4409SJohn Baldwin 93ecdf4409SJohn Baldwin new_list = malloc(sizeof(struct eventhandler_list) + 94ecdf4409SJohn Baldwin strlen(name) + 1, M_EVENTHANDLER, M_WAITOK); 95ecdf4409SJohn Baldwin 96ecdf4409SJohn Baldwin /* If someone else created it already, then use that one. */ 97ecdf4409SJohn Baldwin mtx_lock(&eventhandler_mutex); 98ecdf4409SJohn Baldwin list = _eventhandler_find_list(name); 99ecdf4409SJohn Baldwin if (list != NULL) { 100ecdf4409SJohn Baldwin free(new_list, M_EVENTHANDLER); 101ecdf4409SJohn Baldwin } else { 102ecdf4409SJohn Baldwin CTR2(KTR_EVH, "%s: creating list \"%s\"", __func__, name); 103ecdf4409SJohn Baldwin list = new_list; 104fcb893a8SMike Smith list->el_flags = 0; 105ecdf4409SJohn Baldwin list->el_runcount = 0; 10628fe1a71SAlfred Perlstein bzero(&list->el_lock, sizeof(list->el_lock)); 107fcb893a8SMike Smith list->el_name = (char *)list + sizeof(struct eventhandler_list); 108fcb893a8SMike Smith strcpy(list->el_name, name); 109fcb893a8SMike Smith TAILQ_INSERT_HEAD(&eventhandler_lists, list, el_link); 110fcb893a8SMike Smith } 111fcb893a8SMike Smith } 112ecdf4409SJohn Baldwin } 113ecdf4409SJohn Baldwin if (!(list->el_flags & EHL_INITTED)) { 114fcb893a8SMike Smith TAILQ_INIT(&list->el_entries); 115ecdf4409SJohn Baldwin mtx_init(&list->el_lock, name, "eventhandler list", MTX_DEF); 116ecdf4409SJohn Baldwin atomic_store_rel_int(&list->el_flags, EHL_INITTED); 117fcb893a8SMike Smith } 11819a0f7e1SAlfred Perlstein mtx_unlock(&eventhandler_mutex); 119fcb893a8SMike Smith 120fcb893a8SMike Smith /* allocate an entry for this handler, populate it */ 121ecdf4409SJohn Baldwin eg = malloc(sizeof(struct eventhandler_entry_generic), M_EVENTHANDLER, 122ecdf4409SJohn Baldwin M_WAITOK | M_ZERO); 123fcb893a8SMike Smith eg->func = func; 124fcb893a8SMike Smith eg->ee.ee_arg = arg; 125fcb893a8SMike Smith eg->ee.ee_priority = priority; 126ecdf4409SJohn Baldwin KASSERT(priority != EHE_DEAD_PRIORITY, 127ecdf4409SJohn Baldwin ("%s: handler for %s registered with dead priority", __func__, name)); 128fcb893a8SMike Smith 129fcb893a8SMike Smith /* sort it into the list */ 130ecdf4409SJohn Baldwin CTR4(KTR_EVH, "%s: adding item %p (function %p) to \"%s\"", __func__, eg, 131ecdf4409SJohn Baldwin func, name); 132ecdf4409SJohn Baldwin EHL_LOCK(list); 133ecdf4409SJohn Baldwin TAILQ_FOREACH(ep, &list->el_entries, ee_link) { 134ecdf4409SJohn Baldwin if (ep->ee_priority != EHE_DEAD_PRIORITY && 135ecdf4409SJohn Baldwin eg->ee.ee_priority < ep->ee_priority) { 136fcb893a8SMike Smith TAILQ_INSERT_BEFORE(ep, &eg->ee, ee_link); 137fcb893a8SMike Smith break; 138fcb893a8SMike Smith } 139fcb893a8SMike Smith } 140fcb893a8SMike Smith if (ep == NULL) 141fcb893a8SMike Smith TAILQ_INSERT_TAIL(&list->el_entries, &eg->ee, ee_link); 142ecdf4409SJohn Baldwin EHL_UNLOCK(list); 143fcb893a8SMike Smith return(&eg->ee); 144fcb893a8SMike Smith } 145fcb893a8SMike Smith 146fcb893a8SMike Smith void 147fcb893a8SMike Smith eventhandler_deregister(struct eventhandler_list *list, eventhandler_tag tag) 148fcb893a8SMike Smith { 149fcb893a8SMike Smith struct eventhandler_entry *ep = tag; 150fcb893a8SMike Smith 151ecdf4409SJohn Baldwin EHL_LOCK_ASSERT(list, MA_OWNED); 152fcb893a8SMike Smith if (ep != NULL) { 153fcb893a8SMike Smith /* remove just this entry */ 154ecdf4409SJohn Baldwin if (list->el_runcount == 0) { 155ecdf4409SJohn Baldwin CTR3(KTR_EVH, "%s: removing item %p from \"%s\"", __func__, ep, 156ecdf4409SJohn Baldwin list->el_name); 157fcb893a8SMike Smith TAILQ_REMOVE(&list->el_entries, ep, ee_link); 158fcb893a8SMike Smith free(ep, M_EVENTHANDLER); 159fcb893a8SMike Smith } else { 160ecdf4409SJohn Baldwin CTR3(KTR_EVH, "%s: marking item %p from \"%s\" as dead", __func__, 161ecdf4409SJohn Baldwin ep, list->el_name); 162ecdf4409SJohn Baldwin ep->ee_priority = EHE_DEAD_PRIORITY; 163ecdf4409SJohn Baldwin } 164ecdf4409SJohn Baldwin } else { 165fcb893a8SMike Smith /* remove entire list */ 166ecdf4409SJohn Baldwin if (list->el_runcount == 0) { 167ecdf4409SJohn Baldwin CTR2(KTR_EVH, "%s: removing all items from \"%s\"", __func__, 168ecdf4409SJohn Baldwin list->el_name); 169fcb893a8SMike Smith while (!TAILQ_EMPTY(&list->el_entries)) { 170fcb893a8SMike Smith ep = TAILQ_FIRST(&list->el_entries); 1711b727751SPoul-Henning Kamp TAILQ_REMOVE(&list->el_entries, ep, ee_link); 172fcb893a8SMike Smith free(ep, M_EVENTHANDLER); 173fcb893a8SMike Smith } 174ecdf4409SJohn Baldwin } else { 175ecdf4409SJohn Baldwin CTR2(KTR_EVH, "%s: marking all items from \"%s\" as dead", 176ecdf4409SJohn Baldwin __func__, list->el_name); 177ecdf4409SJohn Baldwin TAILQ_FOREACH(ep, &list->el_entries, ee_link) 178ecdf4409SJohn Baldwin ep->ee_priority = EHE_DEAD_PRIORITY; 179fcb893a8SMike Smith } 180ecdf4409SJohn Baldwin } 181ecdf4409SJohn Baldwin EHL_UNLOCK(list); 182fcb893a8SMike Smith } 183fcb893a8SMike Smith 184ecdf4409SJohn Baldwin /* 185ecdf4409SJohn Baldwin * Internal version for use when eventhandler list is already locked. 186ecdf4409SJohn Baldwin */ 187ecdf4409SJohn Baldwin static struct eventhandler_list * 188fdf20233SJoseph Koshy _eventhandler_find_list(const char *name) 189ecdf4409SJohn Baldwin { 190ecdf4409SJohn Baldwin struct eventhandler_list *list; 191ecdf4409SJohn Baldwin 192ecdf4409SJohn Baldwin mtx_assert(&eventhandler_mutex, MA_OWNED); 193ecdf4409SJohn Baldwin TAILQ_FOREACH(list, &eventhandler_lists, el_link) { 194ecdf4409SJohn Baldwin if (!strcmp(name, list->el_name)) 195ecdf4409SJohn Baldwin break; 196ecdf4409SJohn Baldwin } 197ecdf4409SJohn Baldwin return (list); 198ecdf4409SJohn Baldwin } 199ecdf4409SJohn Baldwin 200ecdf4409SJohn Baldwin /* 201ecdf4409SJohn Baldwin * Lookup a "slow" list by name. Returns with the list locked. 202ecdf4409SJohn Baldwin */ 203fcb893a8SMike Smith struct eventhandler_list * 204fdf20233SJoseph Koshy eventhandler_find_list(const char *name) 205fcb893a8SMike Smith { 206fcb893a8SMike Smith struct eventhandler_list *list; 207146be906SJake Burkholder 208146be906SJake Burkholder if (!eventhandler_lists_initted) 209146be906SJake Burkholder return(NULL); 210fcb893a8SMike Smith 211fcb893a8SMike Smith /* scan looking for the requested list */ 2129ed346baSBosko Milekic mtx_lock(&eventhandler_mutex); 213ecdf4409SJohn Baldwin list = _eventhandler_find_list(name); 214ecdf4409SJohn Baldwin if (list != NULL) 215ecdf4409SJohn Baldwin EHL_LOCK(list); 2169ed346baSBosko Milekic mtx_unlock(&eventhandler_mutex); 2176595c331SMike Smith 218fcb893a8SMike Smith return(list); 219fcb893a8SMike Smith } 2206595c331SMike Smith 221ecdf4409SJohn Baldwin /* 222ecdf4409SJohn Baldwin * Prune "dead" entries from an eventhandler list. 223ecdf4409SJohn Baldwin */ 224ecdf4409SJohn Baldwin void 225ecdf4409SJohn Baldwin eventhandler_prune_list(struct eventhandler_list *list) 226ecdf4409SJohn Baldwin { 227ecdf4409SJohn Baldwin struct eventhandler_entry *ep, *en; 228ecdf4409SJohn Baldwin 229ecdf4409SJohn Baldwin CTR2(KTR_EVH, "%s: pruning list \"%s\"", __func__, list->el_name); 230ecdf4409SJohn Baldwin EHL_LOCK_ASSERT(list, MA_OWNED); 231ecdf4409SJohn Baldwin ep = TAILQ_FIRST(&list->el_entries); 232ecdf4409SJohn Baldwin while (ep != NULL) { 233ecdf4409SJohn Baldwin en = TAILQ_NEXT(ep, ee_link); 234ecdf4409SJohn Baldwin if (ep->ee_priority == EHE_DEAD_PRIORITY) { 235ecdf4409SJohn Baldwin TAILQ_REMOVE(&list->el_entries, ep, ee_link); 236ecdf4409SJohn Baldwin free(ep, M_EVENTHANDLER); 237ecdf4409SJohn Baldwin } 238ecdf4409SJohn Baldwin ep = en; 239ecdf4409SJohn Baldwin } 240ecdf4409SJohn Baldwin } 241