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 1.6 2004/12/30 07:01:52 cpressey 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 #error "This file should not be included by userland programs."
  37 #endif
  38
  39 struct eventhandler_entry
  40 {
  41     TAILQ_ENTRY(eventhandler_entry)     ee_link;
  42     int                                 ee_priority;
  43     void                                *ee_arg;
  44 };
  45
  46 struct eventhandler_list
  47 {
  48     TAILQ_ENTRY(eventhandler_list)      el_link;
  49     char                                *el_name;
  50     int                                 el_flags;
  51 #define EHE_INITTED     (1<<0)
  52     TAILQ_HEAD(,eventhandler_entry)     el_entries;
  53 };
  54
  55 typedef struct eventhandler_entry       *eventhandler_tag;
  56
  57 /*
  58  * Fast handler lists require the eventhandler list be present
  59  * at link time.  They don't allow addition of entries to
  60  * unknown eventhandler lists, ie. each list must have an
  61  * "owner".
  62  *
  63  * Fast handler lists must be defined once by the owner
  64  * of the eventhandler list, and the declaration must be in
  65  * scope at any point the list is manipulated.
  66  */
  67 #define EVENTHANDLER_FAST_DECLARE(name, type)                   \
  68 extern struct eventhandler_list Xeventhandler_list_ ## name ;   \
  69 struct eventhandler_entry_ ## name                              \
  70 {                                                               \
  71     struct eventhandler_entry   ee;                             \
  72     type                eh_func;                                \
  73 };                                                              \
  74 struct __hack
  75
  76 #define EVENTHANDLER_FAST_DEFINE(name, type)                            \
  77 struct eventhandler_list Xeventhandler_list_ ## name = { #name };       \
  78 struct __hack
  79
  80 #define EVENTHANDLER_FAST_INVOKE(name, args...)                         \
  81 do {                                                                    \
  82     struct eventhandler_list *_el = &Xeventhandler_list_ ## name ;      \
  83     struct eventhandler_entry *_ep = TAILQ_FIRST(&(_el->el_entries));   \
  84                                                                         \
  85     while (_ep != NULL) {                                               \
  86         ((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg , ## args); \
  87         _ep = TAILQ_NEXT(_ep, ee_link);                                 \
  88     }                                                                   \
  89 } while (0)
  90
  91 #define EVENTHANDLER_FAST_REGISTER(name, func, arg, priority) \
  92     eventhandler_register(Xeventhandler_list_ ## name, #name, func, arg, priority)
  93
  94 #define EVENTHANDLER_FAST_DEREGISTER(name, tag) \
  95     eventhandler_deregister(Xeventhandler_list ## name, tag)
  96
  97
  98 /*
  99  * Slow handlers are entirely dynamic; lists are created
 100  * when entries are added to them, and thus have no concept of "owner".
 101  *
 102  * Slow handlers need to be declared, but do not need to be defined. The
 103  * declaration must be in scope wherever the handler is to be invoked.
 104  */
 105 #define EVENTHANDLER_DECLARE(name, type)        \
 106 struct eventhandler_entry_ ## name              \
 107 {                                               \
 108     struct eventhandler_entry   ee;             \
 109     type                eh_func;                \
 110 };                                              \
 111 struct __hack
 112
 113 #define EVENTHANDLER_INVOKE(name, args...)                              \
 114 do {                                                                    \
 115     struct eventhandler_list *_el;                                      \
 116     struct eventhandler_entry *_ep;                                     \
 117                                                                         \
 118     if ((_el = eventhandler_find_list(#name)) != NULL) {                \
 119         for (_ep = TAILQ_FIRST(&(_el->el_entries));                     \
 120              _ep != NULL;                                               \
 121              _ep = TAILQ_NEXT(_ep, ee_link)) {                          \
 122             ((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg , ## args); \
 123         }                                                               \
 124     }                                                                   \
 125 } while (0)
 126
 127 #define EVENTHANDLER_REGISTER(name, func, arg, priority) \
 128     eventhandler_register(NULL, #name, func, arg, priority)
 129
 130 #define EVENTHANDLER_DEREGISTER(name, tag)              \
 131 do {                                                    \
 132     struct eventhandler_list *_el;                      \
 133                                                         \
 134     if ((_el = eventhandler_find_list(#name)) != NULL)  \
 135         eventhandler_deregister(_el, tag);              \
 136 } while(0)
 137
 138
 139 #ifdef _KERNEL
 140 extern eventhandler_tag eventhandler_register(struct eventhandler_list *list,
 141                                               char *name,
 142                                               void *func,
 143                                               void *arg,
 144                                               int priority);
 145 extern void             eventhandler_deregister(struct eventhandler_list *list,
 146                                                 eventhandler_tag tag);
 147 extern struct eventhandler_list *eventhandler_find_list(char *name);
 148 #endif /* _KERNEL */
 149
 150 /*
 151  * Standard system event queues.
 152  */
 153
 154 /* Generic priority levels */
 155 #define EVENTHANDLER_PRI_FIRST  0
 156 #define EVENTHANDLER_PRI_ANY    10000
 157 #define EVENTHANDLER_PRI_LAST   20000
 158
 159 /* Shutdown events */
 160 typedef void (*shutdown_fn) (void *, int);
 161
 162 #define SHUTDOWN_PRI_FIRST      EVENTHANDLER_PRI_FIRST
 163 #define SHUTDOWN_PRI_DEFAULT    EVENTHANDLER_PRI_ANY
 164 #define SHUTDOWN_PRI_LAST       EVENTHANDLER_PRI_LAST
 165
 166 EVENTHANDLER_DECLARE(shutdown_pre_sync, shutdown_fn);   /* before fs sync */
 167 EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn);  /* after fs sync */
 168 EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);
 169
 170 #endif /* SYS_EVENTHANDLER_H */