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/lock.h>
  33 #include <sys/ktr.h>
  34 #include <sys/mutex.h>
  35 #include <sys/queue.h>
  36
  37 struct eventhandler_entry {
  38         TAILQ_ENTRY(eventhandler_entry) ee_link;
  39         int                             ee_priority;
  40 #define EHE_DEAD_PRIORITY       (-1)
  41         void                            *ee_arg;
  42 };
  43
  44 struct eventhandler_list {
  45         char                            *el_name;
  46         int                             el_flags;
  47 #define EHL_INITTED     (1<<0)
  48         u_int                           el_runcount;
  49         struct mtx                      el_lock;
  50         TAILQ_ENTRY(eventhandler_list)  el_link;
  51         TAILQ_HEAD(,eventhandler_entry) el_entries;
  52 };
  53
  54 typedef struct eventhandler_entry       *eventhandler_tag;
  55
  56 #define EHL_LOCK(p)             mtx_lock(&(p)->el_lock)
  57 #define EHL_UNLOCK(p)           mtx_unlock(&(p)->el_lock)
  58 #define EHL_LOCK_ASSERT(p, x)   mtx_assert(&(p)->el_lock, x)
  59
  60 /*
  61  * Macro to invoke the handlers for a given event.
  62  */
  63 #define _EVENTHANDLER_INVOKE(name, list, ...) do {                      \
  64         struct eventhandler_entry *_ep;                                 \
  65         struct eventhandler_entry_ ## name *_t;                         \
  66                                                                         \
  67         KASSERT((list)->el_flags & EHL_INITTED,                         \
  68            ("eventhandler_invoke: running non-inited list"));           \
  69         EHL_LOCK_ASSERT((list), MA_OWNED);                              \
  70         (list)->el_runcount++;                                          \
  71         KASSERT((list)->el_runcount > 0,                                \
  72             ("eventhandler_invoke: runcount overflow"));                \
  73         CTR0(KTR_EVH, "eventhandler_invoke(\"" __STRING(name) "\")");   \
  74         TAILQ_FOREACH(_ep, &((list)->el_entries), ee_link) {            \
  75                 if (_ep->ee_priority != EHE_DEAD_PRIORITY) {            \
  76                         EHL_UNLOCK((list));                             \
  77                         _t = (struct eventhandler_entry_ ## name *)_ep; \
  78                         CTR1(KTR_EVH, "eventhandler_invoke: executing %p", \
  79                             (void *)_t->eh_func);                       \
  80                         _t->eh_func(_ep->ee_arg , ## __VA_ARGS__);      \
  81                         EHL_LOCK((list));                               \
  82                 }                                                       \
  83         }                                                               \
  84         KASSERT((list)->el_runcount > 0,                                \
  85             ("eventhandler_invoke: runcount underflow"));               \
  86         (list)->el_runcount--;                                          \
  87         if ((list)->el_runcount == 0)                                   \
  88                 eventhandler_prune_list(list);                          \
  89         EHL_UNLOCK((list));                                             \
  90 } while (0)
  91
  92 /*
  93  * Slow handlers are entirely dynamic; lists are created
  94  * when entries are added to them, and thus have no concept of "owner",
  95  *
  96  * Slow handlers need to be declared, but do not need to be defined. The
  97  * declaration must be in scope wherever the handler is to be invoked.
  98  */
  99 #define EVENTHANDLER_DECLARE(name, type)                                \
 100 struct eventhandler_entry_ ## name                                      \
 101 {                                                                       \
 102         struct eventhandler_entry       ee;                             \
 103         type                            eh_func;                        \
 104 };                                                                      \
 105 struct __hack
 106
 107 #define EVENTHANDLER_DEFINE(name, func, arg, priority)                  \
 108         static eventhandler_tag name ## _tag;                           \
 109         static void name ## _evh_init(void *ctx)                        \
 110         {                                                               \
 111                 name ## _tag = EVENTHANDLER_REGISTER(name, func, ctx,   \
 112                     priority);                                          \
 113         }                                                               \
 114         SYSINIT(name ## _evh_init, SI_SUB_CONFIGURE, SI_ORDER_ANY,      \
 115             name ## _evh_init, arg);                                    \
 116         struct __hack
 117
 118 #define EVENTHANDLER_INVOKE(name, ...)                                  \
 119 do {                                                                    \
 120         struct eventhandler_list *_el;                                  \
 121                                                                         \
 122         if ((_el = eventhandler_find_list(#name)) != NULL)              \
 123                 _EVENTHANDLER_INVOKE(name, _el , ## __VA_ARGS__);       \
 124 } while (0)
 125
 126 #define EVENTHANDLER_REGISTER(name, func, arg, priority)                \
 127         eventhandler_register(NULL, #name, func, arg, priority)
 128
 129 #define EVENTHANDLER_DEREGISTER(name, tag)                              \
 130 do {                                                                    \
 131         struct eventhandler_list *_el;                                  \
 132                                                                         \
 133         if ((_el = eventhandler_find_list(#name)) != NULL)              \
 134                 eventhandler_deregister(_el, tag);                      \
 135 } while(0)
 136
 137
 138 eventhandler_tag eventhandler_register(struct eventhandler_list *list,
 139             const char *name, void *func, void *arg, int priority);
 140 void    eventhandler_deregister(struct eventhandler_list *list,
 141             eventhandler_tag tag);
 142 struct eventhandler_list *eventhandler_find_list(const char *name);
 143 void    eventhandler_prune_list(struct eventhandler_list *list);
 144
 145 /*
 146  * Standard system event queues.
 147  */
 148
 149 /* Generic priority levels */
 150 #define EVENTHANDLER_PRI_FIRST  0
 151 #define EVENTHANDLER_PRI_ANY    10000
 152 #define EVENTHANDLER_PRI_LAST   20000
 153
 154 /* Shutdown events */
 155 typedef void (*shutdown_fn)(void *, int);
 156
 157 #define SHUTDOWN_PRI_FIRST      EVENTHANDLER_PRI_FIRST
 158 #define SHUTDOWN_PRI_DEFAULT    EVENTHANDLER_PRI_ANY
 159 #define SHUTDOWN_PRI_LAST       EVENTHANDLER_PRI_LAST
 160
 161 EVENTHANDLER_DECLARE(shutdown_pre_sync, shutdown_fn);   /* before fs sync */
 162 EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn);  /* after fs sync */
 163 EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);
 164
 165 /* Low memory event */
 166 typedef void (*vm_lowmem_handler_t)(void *, int);
 167 #define LOWMEM_PRI_DEFAULT      EVENTHANDLER_PRI_FIRST
 168 EVENTHANDLER_DECLARE(vm_lowmem, vm_lowmem_handler_t);
 169
 170 /* Low vnodes event */
 171 typedef void (*vfs_lowvnodes_handler_t)(void *, int);
 172 EVENTHANDLER_DECLARE(vfs_lowvnodes, vfs_lowvnodes_handler_t);
 173
 174 /* VLAN state change events */
 175 struct ifnet;
 176 typedef void (*vlan_config_fn)(void *, struct ifnet *, uint16_t);
 177 typedef void (*vlan_unconfig_fn)(void *, struct ifnet *, uint16_t);
 178 EVENTHANDLER_DECLARE(vlan_config, vlan_config_fn);
 179 EVENTHANDLER_DECLARE(vlan_unconfig, vlan_unconfig_fn);
 180
 181 /*
 182  * Process events
 183  * process_fork and exit handlers are called without Giant.
 184  * exec handlers are called with Giant, but that is by accident.
 185  */
 186 struct proc;
 187 struct image_params;
 188
 189 typedef void (*exitlist_fn)(void *, struct proc *);
 190 typedef void (*forklist_fn)(void *, struct proc *, struct proc *, int);
 191 typedef void (*execlist_fn)(void *, struct proc *, struct image_params *);
 192 typedef void (*proc_ctor_fn)(void *, struct proc *);
 193 typedef void (*proc_dtor_fn)(void *, struct proc *);
 194 typedef void (*proc_init_fn)(void *, struct proc *);
 195 typedef void (*proc_fini_fn)(void *, struct proc *);
 196 EVENTHANDLER_DECLARE(process_ctor, proc_ctor_fn);
 197 EVENTHANDLER_DECLARE(process_dtor, proc_dtor_fn);
 198 EVENTHANDLER_DECLARE(process_init, proc_init_fn);
 199 EVENTHANDLER_DECLARE(process_fini, proc_fini_fn);
 200 EVENTHANDLER_DECLARE(process_exit, exitlist_fn);
 201 EVENTHANDLER_DECLARE(process_fork, forklist_fn);
 202 EVENTHANDLER_DECLARE(process_exec, execlist_fn);
 203
 204 struct thread;
 205 typedef void (*thread_ctor_fn)(void *, struct thread *);
 206 typedef void (*thread_dtor_fn)(void *, struct thread *);
 207 typedef void (*thread_fini_fn)(void *, struct thread *);
 208 typedef void (*thread_init_fn)(void *, struct thread *);
 209 EVENTHANDLER_DECLARE(thread_ctor, thread_ctor_fn);
 210 EVENTHANDLER_DECLARE(thread_dtor, thread_dtor_fn);
 211 EVENTHANDLER_DECLARE(thread_init, thread_init_fn);
 212 EVENTHANDLER_DECLARE(thread_fini, thread_fini_fn);
 213
 214 typedef void (*uma_zone_chfn)(void *);
 215 EVENTHANDLER_DECLARE(nmbclusters_change, uma_zone_chfn);
 216 EVENTHANDLER_DECLARE(maxsockets_change, uma_zone_chfn);
 217
 218 typedef void(*schedtail_fn)(void *, struct proc *);
 219 EVENTHANDLER_DECLARE(schedtail, schedtail_fn);
 220 #endif /* SYS_EVENTHANDLER_H */