1/* $NetBSD: reentrant.h,v 1.20 2017/02/08 18:00:37 christos Exp $ */
2
3/*-
4 * Copyright (c) 1997, 1998, 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by J.T. Conklin, by Nathan J. Williams, and by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Requirements:
34 *
35 * 1. The thread safe mechanism should be lightweight so the library can
36 * be used by non-threaded applications without unreasonable overhead.
37 *
38 * 2. There should be no dependency on a thread engine for non-threaded
39 * applications.
40 *
41 * 3. There should be no dependency on any particular thread engine.
42 *
43 * 4. The library should be able to be compiled without support for thread
44 * safety.
45 *
46 *
47 * Rationale:
48 *
49 * One approach for thread safety is to provide discrete versions of the
50 * library: one thread safe, the other not. The disadvantage of this is
51 * that libc is rather large, and two copies of a library which are 99%+
52 * identical is not an efficent use of resources.
53 *
54 * Another approach is to provide a single thread safe library. However,
55 * it should not add significant run time or code size overhead to non-
56 * threaded applications.
57 *
58 * Since the NetBSD C library is used in other projects, it should be
59 * easy to replace the mutual exclusion primitives with ones provided by
60 * another system. Similarly, it should also be easy to remove all
61 * support for thread safety completely if the target environment does
62 * not support threads.
63 *
64 *
65 * Implementation Details:
66 *
67 * The thread primitives used by the library (mutex_t, mutex_lock, etc.)
68 * are macros which expand to the cooresponding primitives provided by
69 * the thread engine or to nothing. The latter is used so that code is
70 * not unreasonably cluttered with #ifdefs when all thread safe support
71 * is removed.
72 *
73 * The thread macros can be directly mapped to the mutex primitives from
74 * pthreads, however it should be reasonably easy to wrap another mutex
75 * implementation so it presents a similar interface.
76 *
77 * The thread functions operate by dispatching to symbols which are, by
78 * default, weak-aliased to no-op functions in thread-stub/thread-stub.c
79 * (some uses of thread operations are conditional on __isthreaded, but
80 * not all of them are).
81 *
82 * When the thread library is linked in, it provides strong-alias versions
83 * of those symbols which dispatch to its own real thread operations.
84 *
85 */
86
87/*
88 * Abstract thread interface for thread-safe libraries. These routines
89 * will use stubs in libc if the application is not linked against the
90 * pthread library, and the real function in the pthread library if it
91 * is.
92 */
93
94#include <pthread.h>
95#include <signal.h>
96
97#define mutex_t pthread_mutex_t
98#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
99
100#define mutexattr_t pthread_mutexattr_t
101
102#define MUTEX_TYPE_NORMAL PTHREAD_MUTEX_NORMAL
103#define MUTEX_TYPE_ERRORCHECK PTHREAD_MUTEX_ERRORCHECK
104#define MUTEX_TYPE_RECURSIVE PTHREAD_MUTEX_RECURSIVE
105
106#define cond_t pthread_cond_t
107#define COND_INITIALIZER PTHREAD_COND_INITIALIZER
108
109#define condattr_t pthread_condattr_t
110
111#define rwlock_t pthread_rwlock_t
112#define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER
113
114#define rwlockattr_t pthread_rwlockattr_t
115
116#define thread_key_t pthread_key_t
117
118#define thr_t pthread_t
119
120#define thrattr_t pthread_attr_t
121
122#define once_t pthread_once_t
123#define ONCE_INITIALIZER PTHREAD_ONCE_INIT
124
125#ifdef _REENTRANT
126
127#ifndef __LIBC_THREAD_STUBS
128
129__BEGIN_DECLS
130int __libc_mutex_init(mutex_t *, const mutexattr_t *);
131int __libc_mutex_lock(mutex_t *);
132int __libc_mutex_trylock(mutex_t *);
133int __libc_mutex_unlock(mutex_t *);
134int __libc_mutex_destroy(mutex_t *);
135
136int __libc_mutexattr_init(mutexattr_t *);
137int __libc_mutexattr_settype(mutexattr_t *, int);
138int __libc_mutexattr_destroy(mutexattr_t *);
139__END_DECLS
140
141#define mutex_init(m, a) __libc_mutex_init((m), (a))
142#define mutex_lock(m) __libc_mutex_lock((m))
143#define mutex_trylock(m) __libc_mutex_trylock((m))
144#define mutex_unlock(m) __libc_mutex_unlock((m))
145#define mutex_destroy(m) __libc_mutex_destroy((m))
146
147#define mutexattr_init(ma) __libc_mutexattr_init((ma))
148#define mutexattr_settype(ma, t) __libc_mutexattr_settype((ma), (t))
149#define mutexattr_destroy(ma) __libc_mutexattr_destroy((ma))
150
151__BEGIN_DECLS
152int __libc_cond_init(cond_t *, const condattr_t *);
153int __libc_cond_signal(cond_t *);
154int __libc_cond_broadcast(cond_t *);
155int __libc_cond_wait(cond_t *, mutex_t *);
156#ifndef __LIBC12_SOURCE__
157int __libc_cond_timedwait(cond_t *, mutex_t *, const struct timespec *);
158#endif
159int __libc_cond_destroy(cond_t *);
160__END_DECLS
161
162#define cond_init(c, t, a) __libc_cond_init((c), (a))
163#define cond_signal(c) __libc_cond_signal((c))
164#define cond_broadcast(c) __libc_cond_broadcast((c))
165#define cond_wait(c, m) __libc_cond_wait((c), (m))
166#define cond_timedwait(c, m, t) __libc_cond_timedwait((c), (m), (t))
167#define cond_destroy(c) __libc_cond_destroy((c))
168
169__BEGIN_DECLS
170int __libc_rwlock_init(rwlock_t *, const rwlockattr_t *);
171int __libc_rwlock_rdlock(rwlock_t *);
172int __libc_rwlock_wrlock(rwlock_t *);
173int __libc_rwlock_tryrdlock(rwlock_t *);
174int __libc_rwlock_trywrlock(rwlock_t *);
175int __libc_rwlock_unlock(rwlock_t *);
176int __libc_rwlock_destroy(rwlock_t *);
177__END_DECLS
178
179#define rwlock_init(l, a) __libc_rwlock_init((l), (a))
180#define rwlock_rdlock(l) __libc_rwlock_rdlock((l))
181#define rwlock_wrlock(l) __libc_rwlock_wrlock((l))
182#define rwlock_tryrdlock(l) __libc_rwlock_tryrdlock((l))
183#define rwlock_trywrlock(l) __libc_rwlock_trywrlock((l))
184#define rwlock_unlock(l) __libc_rwlock_unlock((l))
185#define rwlock_destroy(l) __libc_rwlock_destroy((l))
186
187__BEGIN_DECLS
188int __libc_thr_keycreate(thread_key_t *, void (*)(void *));
189int __libc_thr_setspecific(thread_key_t, const void *);
190void *__libc_thr_getspecific(thread_key_t);
191int __libc_thr_keydelete(thread_key_t);
192__END_DECLS
193
194#define thr_keycreate(k, d) __libc_thr_keycreate((k), (d))
195#define thr_setspecific(k, p) __libc_thr_setspecific((k), (p))
196#define thr_getspecific(k) __libc_thr_getspecific((k))
197#define thr_keydelete(k) __libc_thr_keydelete((k))
198
199__BEGIN_DECLS
200int __libc_thr_once(once_t *, void (*)(void));
201int __libc_thr_sigsetmask(int, const sigset_t *, sigset_t *);
202thr_t __libc_thr_self(void);
203int __libc_thr_yield(void);
204void __libc_thr_create(thr_t *, const thrattr_t *,
205 void *(*)(void *), void *);
206void __libc_thr_exit(void *) __attribute__((__noreturn__));
207int *__libc_thr_errno(void);
208int __libc_thr_setcancelstate(int, int *);
209unsigned int __libc_thr_curcpu(void);
210
211extern int __isthreaded;
212__END_DECLS
213
214#define thr_once(o, f) __libc_thr_once((o), (f))
215#define thr_sigsetmask(f, n, o) __libc_thr_sigsetmask((f), (n), (o))
216#define thr_self() __libc_thr_self()
217#define thr_yield() __libc_thr_yield()
218#define thr_create(tp, ta, f, a) __libc_thr_create((tp), (ta), (f), (a))
219#define thr_exit(v) __libc_thr_exit((v))
220#define thr_errno() __libc_thr_errno()
221#define thr_enabled() (__isthreaded)
222#define thr_setcancelstate(n, o) __libc_thr_setcancelstate((n),(o))
223#define thr_curcpu() __libc_thr_curcpu()
224
225#else /* __LIBC_THREAD_STUBS */
226
227__BEGIN_DECLS
228void __libc_thr_init_stub(void);
229
230int __libc_mutex_init_stub(mutex_t *, const mutexattr_t *);
231int __libc_mutex_lock_stub(mutex_t *);
232int __libc_mutex_trylock_stub(mutex_t *);
233int __libc_mutex_unlock_stub(mutex_t *);
234int __libc_mutex_destroy_stub(mutex_t *);
235
236int __libc_mutexattr_init_stub(mutexattr_t *);
237int __libc_mutexattr_destroy_stub(mutexattr_t *);
238int __libc_mutexattr_settype_stub(mutexattr_t *, int);
239
240int __libc_cond_init_stub(cond_t *, const condattr_t *);
241int __libc_cond_signal_stub(cond_t *);
242int __libc_cond_broadcast_stub(cond_t *);
243int __libc_cond_wait_stub(cond_t *, mutex_t *);
244int __libc_cond_timedwait_stub(cond_t *, mutex_t *,
245 const struct timespec *);
246int __libc_cond_destroy_stub(cond_t *);
247
248int __libc_rwlock_init_stub(rwlock_t *, const rwlockattr_t *);
249int __libc_rwlock_rdlock_stub(rwlock_t *);
250int __libc_rwlock_wrlock_stub(rwlock_t *);
251int __libc_rwlock_tryrdlock_stub(rwlock_t *);
252int __libc_rwlock_trywrlock_stub(rwlock_t *);
253int __libc_rwlock_unlock_stub(rwlock_t *);
254int __libc_rwlock_destroy_stub(rwlock_t *);
255
256int __libc_thr_keycreate_stub(thread_key_t *, void (*)(void *));
257int __libc_thr_setspecific_stub(thread_key_t, const void *);
258void *__libc_thr_getspecific_stub(thread_key_t);
259int __libc_thr_keydelete_stub(thread_key_t);
260
261int __libc_thr_once_stub(once_t *, void (*)(void));
262int __libc_thr_sigsetmask_stub(int, const sigset_t *, sigset_t *);
263thr_t __libc_thr_self_stub(void);
264int __libc_thr_yield_stub(void);
265int __libc_thr_create_stub(thr_t *, const thrattr_t *,
266 void *(*)(void *), void *);
267void __libc_thr_exit_stub(void *) __dead;
268int *__libc_thr_errno_stub(void);
269int __libc_thr_setcancelstate_stub(int, int *);
270int __libc_thr_equal_stub(pthread_t, pthread_t);
271unsigned int __libc_thr_curcpu_stub(void);
272__END_DECLS
273
274#endif /* __LIBC_THREAD_STUBS */
275
276#define FLOCKFILE(fp) __flockfile_internal(fp, 1)
277#define FUNLOCKFILE(fp) __funlockfile_internal(fp, 1)
278
279#else /* _REENTRANT */
280
281#define mutex_init(m, a) __nothing
282#define mutex_lock(m) __nothing
283#define mutex_trylock(m) __nothing
284#define mutex_unlock(m) __nothing
285#define mutex_destroy(m) __nothing
286
287#define cond_init(c, t, a) __nothing
288#define cond_signal(c) __nothing
289#define cond_broadcast(c) __nothing
290#define cond_wait(c, m) __nothing
291#define cond_timedwait(c, m, t) __nothing
292#define cond_destroy(c) __nothing
293
294#define rwlock_init(l, a) __nothing
295#define rwlock_rdlock(l) __nothing
296#define rwlock_wrlock(l) __nothing
297#define rwlock_tryrdlock(l) __nothing
298#define rwlock_trywrlock(l) __nothing
299#define rwlock_unlock(l) __nothing
300#define rwlock_destroy(l) __nothing
301
302#define thr_keycreate(k, d) /*LINTED*/0
303#define thr_setspecific(k, p) __nothing
304#define thr_getspecific(k) /*LINTED*/0
305#define thr_keydelete(k) __nothing
306
307#define mutexattr_init(ma) __nothing
308#define mutexattr_settype(ma, t) __nothing
309#define mutexattr_destroy(ma) __nothing
310
311static inline int
312thr_once(once_t *once_control, void (*routine)(void))
313{
314 if (__predict_false(once_control->pto_done == 0)) {
315 (*routine)();
316 once_control->pto_done = 1;
317 }
318 return 0;
319}
320#define thr_sigsetmask(f, n, o) __nothing
321#define thr_self() __nothing
322#define thr_errno() __nothing
323#define thr_curcpu() ((unsigned int)0)
324
325#define FLOCKFILE(fp) __nothing
326#define FUNLOCKFILE(fp) __nothing
327
328#endif /* _REENTRANT */
329