sys/sys/eventhandler.h

   1 /*-
   2  * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/sys/eventhandler.h,v 1.5 2000/01/16 06:11:33 bde Exp $
  27  * $DragonFly: src/sys/sys/eventhandler.h,v 1.8 2007/07/11 23:46:54 dillon Exp $
  28  */
  29
  30 #include <sys/queue.h>
  31
  32 #ifndef SYS_EVENTHANDLER_H
  33 #define SYS_EVENTHANDLER_H
  34
  35 #if !defined(_KERNEL) && !defined(_KERNEL_STRUCTURES)
  36
  37 #error "This file should not be included by userland programs."
  38
  39 #else
  40
  41 struct eventhandler_entry
  42 {
  43     TAILQ_ENTRY(eventhandler_entry)     ee_link;
  44     int                                 ee_priority;
  45     void                                *ee_arg;
  46 };
  47
  48 struct eventhandler_list
  49 {
  50     TAILQ_ENTRY(eventhandler_list)      el_link;
  51     char                                *el_name;
  52     int                                 el_flags;
  53 #define EHE_INITTED     (1<<0)
  54     TAILQ_HEAD(,eventhandler_entry)     el_entries;
  55 };
  56
  57 typedef struct eventhandler_entry       *eventhandler_tag;
  58
  59 /*
  60  * Fast handler lists require the eventhandler list be present
  61  * at link time.  They don't allow addition of entries to
  62  * unknown eventhandler lists, ie. each list must have an
  63  * "owner".
  64  *
  65  * Fast handler lists must be defined once by the owner
  66  * of the eventhandler list, and the declaration must be in
  67  * scope at any point the list is manipulated.
  68  */
  69 #define EVENTHANDLER_FAST_DECLARE(name, type)                   \
  70 extern struct eventhandler_list Xeventhandler_list_ ## name ;   \
  71 struct eventhandler_entry_ ## name                              \
  72 {                                                               \
  73     struct eventhandler_entry   ee;                             \
  74     type                eh_func;                                \
  75 };                                                              \
  76 struct __hack
  77
  78 #define EVENTHANDLER_FAST_DEFINE(name, type)                            \
  79 struct eventhandler_list Xeventhandler_list_ ## name = { #name };       \
  80 struct __hack
  81
  82 #define EVENTHANDLER_FAST_INVOKE(name, args...)                         \
  83 do {                                                                    \
  84     struct eventhandler_list *_el = &Xeventhandler_list_ ## name ;      \
  85     struct eventhandler_entry *_ep = TAILQ_FIRST(&(_el->el_entries));   \
  86                                                                         \
  87     while (_ep != NULL) {                                               \
  88         ((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg , ## args); \
  89         _ep = TAILQ_NEXT(_ep, ee_link);                                 \
  90     }                                                                   \
  91 } while (0)
  92
  93 #define EVENTHANDLER_FAST_REGISTER(name, func, arg, priority) \
  94     eventhandler_register(Xeventhandler_list_ ## name, #name, func, arg, priority)
  95
  96 #define EVENTHANDLER_FAST_DEREGISTER(name, tag) \
  97     eventhandler_deregister(Xeventhandler_list ## name, tag)
  98
  99
 100 /*
 101  * Slow handlers are entirely dynamic; lists are created
 102  * when entries are added to them, and thus have no concept of "owner".
 103  *
 104  * Slow handlers need to be declared, but do not need to be defined. The
 105  * declaration must be in scope wherever the handler is to be invoked.
 106  */
 107 #define EVENTHANDLER_DECLARE(name, type)        \
 108 struct eventhandler_entry_ ## name              \
 109 {                                               \
 110     struct eventhandler_entry   ee;             \
 111     type                eh_func;                \
 112 };                                              \
 113 struct __hack
 114
 115 #define EVENTHANDLER_INVOKE(name, args...)                              \
 116 do {                                                                    \
 117     struct eventhandler_list *_el;                                      \
 118     struct eventhandler_entry *_ep;                                     \
 119                                                                         \
 120     if ((_el = eventhandler_find_list(#name)) != NULL) {                \
 121         for (_ep = TAILQ_FIRST(&(_el->el_entries));                     \
 122              _ep != NULL;                                               \
 123              _ep = TAILQ_NEXT(_ep, ee_link)) {                          \
 124             ((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg , ## args); \
 125         }                                                               \
 126     }                                                                   \
 127 } while (0)
 128
 129 #define EVENTHANDLER_REGISTER(name, func, arg, priority) \
 130     eventhandler_register(NULL, #name, func, arg, priority)
 131
 132 #define EVENTHANDLER_DEREGISTER(name, tag)              \
 133 do {                                                    \
 134     struct eventhandler_list *_el;                      \
 135                                                         \
 136     if ((_el = eventhandler_find_list(#name)) != NULL)  \
 137         eventhandler_deregister(_el, tag);              \
 138 } while(0)
 139
 140
 141 #ifdef _KERNEL
 142 extern eventhandler_tag eventhandler_register(struct eventhandler_list *list,
 143                                               char *name,
 144                                               void *func,
 145                                               void *arg,
 146                                               int priority);
 147 extern void             eventhandler_deregister(struct eventhandler_list *list,
 148                                                 eventhandler_tag tag);
 149 extern struct eventhandler_list *eventhandler_find_list(char *name);
 150 #endif /* _KERNEL */
 151
 152 /*
 153  * Standard system event queues.
 154  */
 155
 156 /* Generic priority levels */
 157 #define EVENTHANDLER_PRI_FIRST  0
 158 #define EVENTHANDLER_PRI_ANY    10000
 159 #define EVENTHANDLER_PRI_LAST   20000
 160
 161 /* Shutdown events */
 162 typedef void (*shutdown_fn) (void *, int);
 163
 164 #define SHUTDOWN_PRI_FIRST      EVENTHANDLER_PRI_FIRST
 165 #define SHUTDOWN_PRI_DEFAULT    EVENTHANDLER_PRI_ANY
 166 #define SHUTDOWN_PRI_DRIVER     (EVENTHANDLER_PRI_ANY + 5000)
 167 #define SHUTDOWN_PRI_LAST       EVENTHANDLER_PRI_LAST
 168
 169 EVENTHANDLER_DECLARE(shutdown_pre_sync, shutdown_fn);   /* before fs sync */
 170 EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn);  /* after fs sync */
 171 EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);
 172
 173 #endif  /* _KERNEL */
 174 #endif  /* SYS_EVENTHANDLER_H */