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  * $FreeBSD$
  27  */
  28
  29 #ifndef SYS_EVENTHANDLER_H
  30 #define SYS_EVENTHANDLER_H
  31
  32 #include <sys/queue.h>
  33 #include <sys/lock.h>
  34
  35 struct eventhandler_entry
  36 {
  37     TAILQ_ENTRY(eventhandler_entry)     ee_link;
  38     int                                 ee_priority;
  39     void                                *ee_arg;
  40 };
  41
  42 struct eventhandler_list
  43 {
  44     char                                *el_name;
  45     int                                 el_flags;
  46 #define EHE_INITTED     (1<<0)
  47     struct lock                         el_lock;
  48     TAILQ_ENTRY(eventhandler_list)      el_link;
  49     TAILQ_HEAD(,eventhandler_entry)     el_entries;
  50 };
  51
  52 typedef struct eventhandler_entry       *eventhandler_tag;
  53
  54 /*
  55  * Fast handler lists require the eventhandler list be present
  56  * at link time.  They don't allow addition of entries to
  57  * unknown eventhandler lists, ie. each list must have an
  58  * "owner".
  59  *
  60  * Fast handler lists must be defined once by the owner
  61  * of the eventhandler list, and the declaration must be in
  62  * scope at any point the list is manipulated.
  63  */
  64 #define EVENTHANDLER_FAST_DECLARE(name, type)                   \
  65 extern struct eventhandler_list Xeventhandler_list_ ## name ;   \
  66 struct eventhandler_entry_ ## name                              \
  67 {                                                               \
  68     struct eventhandler_entry   ee;                             \
  69     type                eh_func;                                \
  70 };                                                              \
  71 struct __hack
  72
  73 #define EVENTHANDLER_FAST_DEFINE(name, type)                            \
  74 struct eventhandler_list Xeventhandler_list_ ## name = { #name };       \
  75 struct __hack
  76
  77 #define EVENTHANDLER_FAST_INVOKE(name, args...)                                 \
  78 do {                                                                            \
  79     struct eventhandler_list *_el = &Xeventhandler_list_ ## name ;              \
  80     struct eventhandler_entry *_ep, *_en;                                       \
  81                                                                                 \
  82     if (_el->el_flags & EHE_INITTED) {                                          \
  83         lockmgr(&_el->el_lock, LK_EXCLUSIVE, NULL, CURPROC);                    \
  84         _ep = TAILQ_FIRST(&(_el->el_entries));                                  \
  85         while (_ep != NULL) {                                                   \
  86             _en = TAILQ_NEXT(_ep, ee_link);                                     \
  87             ((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg ,  \
  88                                                                  ## args);      \
  89             _ep = _en;                                                          \
  90         }                                                                       \
  91         lockmgr(&_el->el_lock, LK_RELEASE, NULL, CURPROC);                      \
  92     }                                                                           \
  93 } while (0)
  94
  95 #define EVENTHANDLER_FAST_REGISTER(name, func, arg, priority) \
  96     eventhandler_register(&Xeventhandler_list_ ## name, #name, func, arg, priority)
  97
  98 #define EVENTHANDLER_FAST_DEREGISTER(name, tag) \
  99     eventhandler_deregister(&Xeventhandler_list_ ## name, tag)
 100
 101 /*
 102  * Slow handlers are entirely dynamic; lists are created
 103  * when entries are added to them, and thus have no concept of "owner",
 104  *
 105  * Slow handlers need to be declared, but do not need to be defined. The
 106  * declaration must be in scope wherever the handler is to be invoked.
 107  */
 108 #define EVENTHANDLER_DECLARE(name, type)        \
 109 struct eventhandler_entry_ ## name              \
 110 {                                               \
 111     struct eventhandler_entry   ee;             \
 112     type                eh_func;                \
 113 };                                              \
 114 struct __hack
 115
 116 #define EVENTHANDLER_INVOKE(name, args...)                                      \
 117 do {                                                                            \
 118     struct eventhandler_list *_el;                                              \
 119     struct eventhandler_entry *_ep, *_en;                                       \
 120                                                                                 \
 121     if (((_el = eventhandler_find_list(#name)) != NULL) &&                      \
 122         (_el->el_flags & EHE_INITTED)) {                                        \
 123         lockmgr(&_el->el_lock, LK_EXCLUSIVE, NULL, CURPROC);                    \
 124         _ep = TAILQ_FIRST(&(_el->el_entries));                                  \
 125         while (_ep != NULL) {                                                   \
 126             _en = TAILQ_NEXT(_ep, ee_link);                                     \
 127             ((struct eventhandler_entry_ ## name *)_ep)->eh_func(_ep->ee_arg ,  \
 128                                                                  ## args);      \
 129             _ep = _en;                                                          \
 130         }                                                                       \
 131         lockmgr(&_el->el_lock, LK_RELEASE, NULL, CURPROC);                      \
 132     }                                                                           \
 133 } while (0)
 134
 135 #define EVENTHANDLER_REGISTER(name, func, arg, priority) \
 136     eventhandler_register(NULL, #name, func, arg, priority)
 137
 138 #define EVENTHANDLER_DEREGISTER(name, tag)              \
 139 do {                                                    \
 140     struct eventhandler_list *_el;                      \
 141                                                         \
 142     if ((_el = eventhandler_find_list(#name)) != NULL)  \
 143         eventhandler_deregister(_el, tag);              \
 144 } while(0)
 145
 146
 147 extern eventhandler_tag eventhandler_register(struct eventhandler_list *list,
 148                                               char *name,
 149                                               void *func,
 150                                               void *arg,
 151                                               int priority);
 152 extern void             eventhandler_deregister(struct eventhandler_list *list,
 153                                                 eventhandler_tag tag);
 154 extern struct eventhandler_list *eventhandler_find_list(char *name);
 155
 156 /*
 157  * Standard system event queues.
 158  */
 159
 160 /* Shutdown events */
 161 typedef void (*shutdown_fn) __P((void *, int));
 162
 163 #define SHUTDOWN_PRI_FIRST      0
 164 #define SHUTDOWN_PRI_DEFAULT    10000
 165 #define SHUTDOWN_PRI_LAST       20000
 166
 167 EVENTHANDLER_DECLARE(shutdown_pre_sync, shutdown_fn);   /* before fs sync */
 168 EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn);  /* after fs sync */
 169 EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);
 170
 171 /* Idle process event */
 172 typedef void (*idle_eventhandler_t) __P((void *, int));
 173
 174 #define IDLE_PRI_FIRST          10000
 175 #define IDLE_PRI_LAST           20000
 176 EVENTHANDLER_FAST_DECLARE(idle_event, idle_eventhandler_t);
 177
 178
 179 #endif /* SYS_EVENTHANDLER_H */