bsd/sys/eventhandler.h

   1 /*
   2  * Copyright (c) 2016-2018 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*-
  29  * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
  30  * All rights reserved.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * $FreeBSD$
  54  */
  55
  56 #ifndef _SYS_EVENTHANDLER_H_
  57 #define _SYS_EVENTHANDLER_H_
  58
  59 #include <kern/locks.h>
  60 #include <sys/queue.h>
  61 #include <sys/cdefs.h>
  62 #include <sys/syslog.h>
  63 #include <uuid/uuid.h>
  64
  65 extern int evh_debug;
  66 extern lck_grp_t        *el_lock_grp;
  67 extern lck_attr_t       *el_lock_attr;
  68 extern struct eventhandler_entry_arg eventhandler_entry_dummy_arg;
  69
  70 struct eventhandler_lists_ctxt {
  71         TAILQ_HEAD(, eventhandler_list)  eventhandler_lists;
  72         int eventhandler_lists_initted;
  73         decl_lck_mtx_data(, eventhandler_mutex);
  74 };
  75
  76 struct eventhandler_entry_arg {
  77         uuid_t ee_fm_uuid;      /* Flow manager UUID */
  78         uuid_t ee_fr_uuid;      /* Flow route UUID */
  79 };
  80
  81 struct eventhandler_entry {
  82         TAILQ_ENTRY(eventhandler_entry) ee_link;
  83         int                             ee_priority;
  84 #define EHE_DEAD_PRIORITY       (-1)
  85         struct eventhandler_entry_arg   ee_arg;
  86 };
  87
  88 #define EVENTHANDLER_MAX_NAME   32
  89
  90 struct eventhandler_list {
  91         char                            el_name[EVENTHANDLER_MAX_NAME];
  92         int                             el_flags;
  93 #define EHL_INITTED     (1<<0)
  94         u_int                           el_runcount;
  95         decl_lck_mtx_data(, el_lock);
  96         TAILQ_ENTRY(eventhandler_list)  el_link;
  97         TAILQ_HEAD(, eventhandler_entry) el_entries;
  98 };
  99
 100 typedef struct eventhandler_entry       *eventhandler_tag;
 101
 102 #define EHL_LOCK_INIT(p)        lck_mtx_init(&(p)->el_lock, el_lock_grp, el_lock_attr)
 103 #define EHL_LOCK(p)             lck_mtx_lock(&(p)->el_lock)
 104 #define EHL_LOCK_SPIN(p)        lck_mtx_lock_spin(&(p)->el_lock)
 105 #define EHL_LOCK_CONVERT(p)     lck_mtx_convert_spin(&(p)->el_lock)
 106 #define EHL_UNLOCK(p)           lck_mtx_unlock(&(p)->el_lock)
 107 #define EHL_LOCK_ASSERT(p, x)   LCK_MTX_ASSERT(&(p)->el_lock, x)
 108 #define EHL_LOCK_DESTROY(p)     lck_mtx_destroy(&(p)->el_lock, el_lock_grp)
 109
 110 #define evhlog(x)       do { if (evh_debug >= 1) log x; } while (0)
 111
 112 /*
 113  * Macro to invoke the handlers for a given event.
 114  */
 115 #define _EVENTHANDLER_INVOKE(name, list, ...) do {                      \
 116         struct eventhandler_entry *_ep;                                 \
 117         struct eventhandler_entry_ ## name *_t;                         \
 118                                                                         \
 119         VERIFY((list)->el_flags & EHL_INITTED);                         \
 120         EHL_LOCK_ASSERT((list), LCK_MTX_ASSERT_OWNED);                  \
 121         (list)->el_runcount++;                                          \
 122         VERIFY((list)->el_runcount > 0);                                \
 123         evhlog((LOG_DEBUG, "eventhandler_invoke(\"" __STRING(name) "\")"));     \
 124         TAILQ_FOREACH(_ep, &((list)->el_entries), ee_link) {            \
 125                 if (_ep->ee_priority != EHE_DEAD_PRIORITY) {            \
 126                         EHL_UNLOCK((list));                             \
 127                         _t = (struct eventhandler_entry_ ## name *)_ep; \
 128                         evhlog((LOG_DEBUG, "eventhandler_invoke: executing %p", \
 129                             VM_KERNEL_UNSLIDE((void *)_t->eh_func)));   \
 130                         _t->eh_func(_ep->ee_arg , ## __VA_ARGS__);      \
 131                         EHL_LOCK_SPIN((list));                          \
 132                 }                                                       \
 133         }                                                               \
 134         VERIFY((list)->el_runcount > 0);                                \
 135         (list)->el_runcount--;                                          \
 136         if ((list)->el_runcount == 0) {                                 \
 137                 EHL_LOCK_CONVERT((list));                               \
 138                 eventhandler_prune_list(list);                          \
 139         }                                                               \
 140         EHL_UNLOCK((list));                                             \
 141 } while (0)
 142
 143 /*
 144  * Slow handlers are entirely dynamic; lists are created
 145  * when entries are added to them, and thus have no concept of "owner",
 146  *
 147  * Slow handlers need to be declared, but do not need to be defined. The
 148  * declaration must be in scope wherever the handler is to be invoked.
 149  */
 150 #define EVENTHANDLER_DECLARE(name, type)                                \
 151 struct eventhandler_entry_ ## name                                      \
 152 {                                                                       \
 153         struct eventhandler_entry       ee;                             \
 154         type                            eh_func;                        \
 155 };                                                                      \
 156 struct __hack
 157
 158 /*
 159  * XXX EVENTHANDLER_DEFINE by itself doesn't do much on XNU
 160  * All it does is that it declares the static eventhandler_tag
 161  * and defines an init routine that still needs to called to put the
 162  * event and callback on the list.
 163  */
 164 #define EVENTHANDLER_DEFINE(evthdlr_ref, name, func, arg, priority)                     \
 165         static eventhandler_tag name ## _tag;                           \
 166         static void name ## _evh_init(void *ctx)                        \
 167         {                                                               \
 168                 name ## _tag = EVENTHANDLER_REGISTER(evthdlr_ref, name, func, ctx,      \
 169                     priority);                                          \
 170         }                                                               \
 171         SYSINIT(name ## _evh_init, SI_SUB_CONFIGURE, SI_ORDER_ANY,      \
 172             name ## _evh_init, arg);                                    \
 173         struct __hack
 174
 175 #define EVENTHANDLER_INVOKE(evthdlr_ref, name, ...)                                     \
 176 do {                                                                    \
 177         struct eventhandler_list *_el;                                  \
 178                                                                         \
 179         if ((_el = eventhandler_find_list(evthdlr_ref, #name)) != NULL)                 \
 180                 _EVENTHANDLER_INVOKE(name, _el , ## __VA_ARGS__);       \
 181 } while (0)
 182
 183 #define EVENTHANDLER_REGISTER(evthdlr_ref, name, func, arg, priority)           \
 184         eventhandler_register(evthdlr_ref, NULL, #name, func, arg, priority)
 185
 186 #define EVENTHANDLER_DEREGISTER(evthdlr_ref, name, tag)                                 \
 187 do {                                                                    \
 188         struct eventhandler_list *_el;                                  \
 189                                                                         \
 190         if ((_el = eventhandler_find_list(evthdlr_ref, #name)) != NULL)         \
 191                 eventhandler_deregister(_el, tag);                      \
 192 } while(0)
 193
 194 void eventhandler_init(void);
 195 extern void eventhandler_reap_caches(boolean_t);
 196 eventhandler_tag eventhandler_register(struct eventhandler_lists_ctxt *evthdlr_lists_ctxt,
 197     struct eventhandler_list *list, const char *name, void *func, struct eventhandler_entry_arg arg, int priority);
 198 void eventhandler_deregister(struct eventhandler_list *list,
 199     eventhandler_tag tag);
 200 struct eventhandler_list *eventhandler_find_list(
 201         struct eventhandler_lists_ctxt *evthdlr_lists_ctxt, const char *name);
 202 void eventhandler_prune_list(struct eventhandler_list *list);
 203 void eventhandler_lists_ctxt_init(struct eventhandler_lists_ctxt *evthdlr_lists_ctxt);
 204 void eventhandler_lists_ctxt_destroy(struct eventhandler_lists_ctxt *evthdlr_lists_ctxt);
 205
 206 /* Generic priority levels */
 207 #define EVENTHANDLER_PRI_FIRST  0
 208 #define EVENTHANDLER_PRI_ANY    10000
 209 #define EVENTHANDLER_PRI_LAST   20000
 210
 211 #endif /* _SYS_EVENTHANDLER_H_ */