summaryrefslogtreecommitdiff
path: root/lib/libc/include/thread_private.h
blob: 673fb9c6a698fe2b352461f9748087aaed52b6c5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/* $OpenBSD: thread_private.h,v 1.25 2011/10/16 06:29:56 guenther Exp $ */

/* PUBLIC DOMAIN: No Rights Reserved. Marco S Hyman <marc@snafu.org> */

#ifndef _THREAD_PRIVATE_H_
#define _THREAD_PRIVATE_H_

/*
 * This file defines the thread library interface to libc.  Thread
 * libraries must implement the functions described here for proper
 * inter-operation with libc.   libc contains weak versions of the
 * described functions for operation in a non-threaded environment.
 */

/*
 * This variable is 0 until a second thread is created.
 */
extern int __isthreaded;

/*
 * Weak symbols are used in libc so that the thread library can
 * efficiently wrap libc functions.
 * 
 * Use WEAK_NAME(n) to get a libc-private name for n (_weak_n),
 *     WEAK_ALIAS(n) to generate the weak symbol n pointing to _weak_n,
 *     WEAK_PROTOTYPE(n) to generate a prototype for _weak_n (based on n).
 */
#define WEAK_NAME(name)		__CONCAT(_weak_,name)
#define WEAK_ALIAS(name)	__weak_alias(name, WEAK_NAME(name))
#ifdef __GNUC__
#define WEAK_PROTOTYPE(name)	__typeof__(name) WEAK_NAME(name)
#else
#define WEAK_PROTOTYPE(name)	/* typeof() only in gcc */
#endif

/*
 * Ditto for hand-written syscall stubs:
 * 
 * Use STUB_NAME(n) to get the strong name of the stub: _thread_sys_n
 *     STUB_ALIAS(n) to generate the weak symbol n pointing to _thread_sys_n,
 *     STUB_PROTOTYPE(n) to generate a prototype for _thread_sys_n (based on n).
 */
#define STUB_NAME(name)		__CONCAT(_thread_sys_,name)
#define STUB_ALIAS(name)	__weak_alias(name, STUB_NAME(name))
#ifdef __GNUC__
#define STUB_PROTOTYPE(name)	__typeof__(name) STUB_NAME(name)
#else
#define STUB_PROTOTYPE(name)	/* typeof() only in gcc */
#endif

/*
 * helper macro to make unique names in the thread namespace
 */
#define __THREAD_NAME(name)	__CONCAT(_thread_tagname_,name)

/*
 * helper functions that exist as (weak) null functions in libc and
 * (strong) functions in the thread library.   These functions:
 *
 * _thread_tag_lock:
 *	lock the mutex associated with the given tag.   If the given
 *	tag is NULL a tag is first allocated.
 *
 * _thread_tag_unlock:
 *	unlock the mutex associated with the given tag.   If the given
 *	tag is NULL a tag is first allocated.
 *
 * _thread_tag_storage:
 *	return a pointer to per thread instance of data associated
 *	with the given tag.  If the given tag is NULL a tag is first
 *	allocated.
 *
 * _thread_mutex_lock:
 *	lock the given mutex. If the given mutex is NULL,
 *	rely on rthreads/pthreads implementation to initialize
 *	the mutex before locking.
 *
 * _thread_mutex_unlock:
 *	unlock the given mutex.
 *
 * _thread_mutex_destroy:
 *	destroy the given mutex.
 */
void	_thread_tag_lock(void **);
void	_thread_tag_unlock(void **);
void   *_thread_tag_storage(void **, void *, size_t, void *);
void	_thread_mutex_lock(void **);
void	_thread_mutex_unlock(void **);
void	_thread_mutex_destroy(void **);

/*
 * Macros used in libc to access thread mutex, keys, and per thread storage.
 * _THREAD_PRIVATE_KEY and _THREAD_PRIVATE_MUTEX are different macros for
 * historical reasons.   They do the same thing, define a static variable
 * keyed by 'name' that identifies a mutex and a key to identify per thread
 * data.
 */
#define _THREAD_PRIVATE_KEY(name)					\
	static void *__THREAD_NAME(name)
#define _THREAD_PRIVATE_MUTEX(name)					\
	static void *__THREAD_NAME(name)
#define _THREAD_PRIVATE_MUTEX_LOCK(name)				\
	_thread_tag_lock(&(__THREAD_NAME(name)))
#define _THREAD_PRIVATE_MUTEX_UNLOCK(name)				\
	_thread_tag_unlock(&(__THREAD_NAME(name)))
#define _THREAD_PRIVATE(keyname, storage, error)			\
	_thread_tag_storage(&(__THREAD_NAME(keyname)), &(storage),	\
			    sizeof (storage), error)

/*
 * Macros used in libc to access mutexes.
 */
#define _MUTEX_LOCK(mutex)						\
	do {								\
		if (__isthreaded)					\
			_thread_mutex_lock(mutex);			\
	} while (0)
#define _MUTEX_UNLOCK(mutex)						\
	do {								\
		if (__isthreaded)					\
			_thread_mutex_unlock(mutex);			\
	} while (0)
#define _MUTEX_DESTROY(mutex)						\
	do {								\
		if (__isthreaded)					\
			_thread_mutex_destroy(mutex);			\
	} while (0)

/*
 * Resolver code is special cased in that it uses global keys.
 */
extern void *__THREAD_NAME(_res);
extern void *__THREAD_NAME(_res_ext);
extern void *__THREAD_NAME(serv_mutex);

/*
 * malloc lock/unlock prototypes and definitions
 */
void	_thread_malloc_lock(void);
void	_thread_malloc_unlock(void);

#define _MALLOC_LOCK()		do {					\
					if (__isthreaded)		\
						_thread_malloc_lock();	\
				} while (0)
#define _MALLOC_UNLOCK()	do {					\
					if (__isthreaded)		\
						_thread_malloc_unlock();\
				} while (0)

void	_thread_atexit_lock(void);
void	_thread_atexit_unlock(void);

#define _ATEXIT_LOCK()		do {					\
					if (__isthreaded)		\
						_thread_atexit_lock();	\
				} while (0)
#define _ATEXIT_UNLOCK()	do {					\
					if (__isthreaded)		\
						_thread_atexit_unlock();\
				} while (0)

void	_thread_arc4_lock(void);
void	_thread_arc4_unlock(void);

#define _ARC4_LOCK()		do {					\
					if (__isthreaded)		\
						_thread_arc4_lock();	\
				} while (0)
#define _ARC4_UNLOCK()		do {					\
					if (__isthreaded)		\
						_thread_arc4_unlock();\
				} while (0)

#endif /* _THREAD_PRIVATE_H_ */