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_INVOKE(name, ...) \
108 do { \
109 struct eventhandler_list *_el; \
110 \
111 if ((_el = eventhandler_find_list(#name)) != NULL) \
112 _EVENTHANDLER_INVOKE(name, _el , ## __VA_ARGS__); \
113 } while (0)
114
115 #define EVENTHANDLER_REGISTER(name, func, arg, priority) \
116 eventhandler_register(NULL, #name, func, arg, priority)
117
118 #define EVENTHANDLER_DEREGISTER(name, tag) \
119 do { \
120 struct eventhandler_list *_el; \
121 \
122 if ((_el = eventhandler_find_list(#name)) != NULL) \
123 eventhandler_deregister(_el, tag); \
124 } while(0)
125
126
127 eventhandler_tag eventhandler_register(struct eventhandler_list *list,
128 const char *name, void *func, void *arg, int priority);
129 void eventhandler_deregister(struct eventhandler_list *list,
130 eventhandler_tag tag);
131 struct eventhandler_list *eventhandler_find_list(const char *name);
132 void eventhandler_prune_list(struct eventhandler_list *list);
133
134 /*
135 * Standard system event queues.
136 */
137
138 /* Generic priority levels */
139 #define EVENTHANDLER_PRI_FIRST 0
140 #define EVENTHANDLER_PRI_ANY 10000
141 #define EVENTHANDLER_PRI_LAST 20000
142
143 /* Shutdown events */
144 typedef void (*shutdown_fn)(void *, int);
145
146 #define SHUTDOWN_PRI_FIRST EVENTHANDLER_PRI_FIRST
147 #define SHUTDOWN_PRI_DEFAULT EVENTHANDLER_PRI_ANY
148 #define SHUTDOWN_PRI_LAST EVENTHANDLER_PRI_LAST
149
150 EVENTHANDLER_DECLARE(shutdown_pre_sync, shutdown_fn); /* before fs sync */
151 EVENTHANDLER_DECLARE(shutdown_post_sync, shutdown_fn); /* after fs sync */
152 EVENTHANDLER_DECLARE(shutdown_final, shutdown_fn);
153
154 /* Low memory event */
155 typedef void (*vm_lowmem_handler_t)(void *, int);
156 #define LOWMEM_PRI_DEFAULT EVENTHANDLER_PRI_FIRST
157 EVENTHANDLER_DECLARE(vm_lowmem, vm_lowmem_handler_t);
158
159 /* Root mounted event */
160 typedef void (*mountroot_handler_t)(void *);
161 EVENTHANDLER_DECLARE(mountroot, mountroot_handler_t);
162
163 /*
164 * Process events
165 * process_fork and exit handlers are called without Giant.
166 * exec handlers are called with Giant, but that is by accident.
167 */
168 struct proc;
169
170 typedef void (*exitlist_fn)(void *, struct proc *);
171 typedef void (*forklist_fn)(void *, struct proc *, struct proc *, int);
172 typedef void (*execlist_fn)(void *, struct proc *);
173
174 EVENTHANDLER_DECLARE(process_exit, exitlist_fn);
175 EVENTHANDLER_DECLARE(process_fork, forklist_fn);
176 EVENTHANDLER_DECLARE(process_exec, execlist_fn);
177
178 typedef void (*uma_zone_chfn)(void *);
179 EVENTHANDLER_DECLARE(nmbclusters_change, uma_zone_chfn);
180 EVENTHANDLER_DECLARE(maxsockets_change, uma_zone_chfn);
181 #endif /* SYS_EVENTHANDLER_H */
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