StdLibPrivateInternalFiles/Include/reentrant.h

   1 /*      $NetBSD: reentrant.h,v 1.10 2004/12/14 00:23:19 nathanw 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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *        This product includes software developed by the NetBSD
  21  *        Foundation, Inc. and its contributors.
  22  * 4. Neither the name of The NetBSD Foundation nor the names of its
  23  *    contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 /*
  40  * Requirements:
  41  *
  42  * 1. The thread safe mechanism should be lightweight so the library can
  43  *    be used by non-threaded applications without unreasonable overhead.
  44  *
  45  * 2. There should be no dependency on a thread engine for non-threaded
  46  *    applications.
  47  *
  48  * 3. There should be no dependency on any particular thread engine.
  49  *
  50  * 4. The library should be able to be compiled without support for thread
  51  *    safety.
  52  *
  53  *
  54  * Rationale:
  55  *
  56  * One approach for thread safety is to provide discrete versions of the
  57  * library: one thread safe, the other not.  The disadvantage of this is
  58  * that libc is rather large, and two copies of a library which are 99%+
  59  * identical is not an efficent use of resources.
  60  *
  61  * Another approach is to provide a single thread safe library.  However,
  62  * it should not add significant run time or code size overhead to non-
  63  * threaded applications.
  64  *
  65  * Since the NetBSD C library is used in other projects, it should be
  66  * easy to replace the mutual exclusion primitives with ones provided by
  67  * another system.  Similarly, it should also be easy to remove all
  68  * support for thread safety completely if the target environment does
  69  * not support threads.
  70  *
  71  *
  72  * Implementation Details:
  73  *
  74  * The thread primitives used by the library (mutex_t, mutex_lock, etc.)
  75  * are macros which expand to the cooresponding primitives provided by
  76  * the thread engine or to nothing.  The latter is used so that code is
  77  * not unreasonably cluttered with #ifdefs when all thread safe support
  78  * is removed.
  79  *
  80  * The thread macros can be directly mapped to the mutex primitives from
  81  * pthreads, however it should be reasonably easy to wrap another mutex
  82  * implementation so it presents a similar interface.
  83  *
  84  * The thread functions operate by dispatching to symbols which are, by
  85  * default, weak-aliased to no-op functions in thread-stub/thread-stub.c
  86  * (some uses of thread operations are conditional on __isthreaded, but
  87  * not all of them are).
  88  *
  89  * When the thread library is linked in, it provides strong-alias versions
  90  * of those symbols which dispatch to its own real thread operations.
  91  *
  92  */
  93
  94 #ifdef _REENTRANT
  95
  96 /*
  97  * Abtract thread interface for thread-safe libraries.  These routines
  98  * will use stubs in libc if the application is not linked against the
  99  * pthread library, and the real function in the pthread library if it
 100  * is.
 101  */
 102
 103 #include <pthread.h>
 104 #include <signal.h>
 105
 106 #define mutex_t                 pthread_mutex_t
 107 #define MUTEX_INITIALIZER       PTHREAD_MUTEX_INITIALIZER
 108
 109 #define mutexattr_t             pthread_mutexattr_t
 110
 111 #define MUTEX_TYPE_NORMAL       PTHREAD_MUTEX_NORMAL
 112 #define MUTEX_TYPE_ERRORCHECK   PTHREAD_MUTEX_ERRORCHECK
 113 #define MUTEX_TYPE_RECURSIVE    PTHREAD_MUTEX_RECURSIVE
 114
 115 #define cond_t                  pthread_cond_t
 116 #define COND_INITIALIZER        PTHREAD_COND_INITIALIZER
 117
 118 #define condattr_t              pthread_condattr_t
 119
 120 #define rwlock_t                pthread_rwlock_t
 121 #define RWLOCK_INITIALIZER      PTHREAD_RWLOCK_INITIALIZER
 122
 123 #define rwlockattr_t            pthread_rwlockattr_t
 124
 125 #define thread_key_t            pthread_key_t
 126
 127 #define thr_t                   pthread_t
 128
 129 #define thrattr_t               pthread_attr_t
 130
 131 #define once_t                  pthread_once_t
 132 #define ONCE_INITIALIZER        PTHREAD_ONCE_INIT
 133
 134 #ifndef __LIBC_THREAD_STUBS
 135
 136 __BEGIN_DECLS
 137 int     __libc_mutex_init(mutex_t *, const mutexattr_t *);
 138 int     __libc_mutex_lock(mutex_t *);
 139 int     __libc_mutex_trylock(mutex_t *);
 140 int     __libc_mutex_unlock(mutex_t *);
 141 int     __libc_mutex_destroy(mutex_t *);
 142
 143 int     __libc_mutexattr_init(mutexattr_t *);
 144 int     __libc_mutexattr_settype(mutexattr_t *, int);
 145 int     __libc_mutexattr_destroy(mutexattr_t *);
 146 __END_DECLS
 147
 148 #define mutex_init(m, a)        __libc_mutex_init((m), (a))
 149 #define mutex_lock(m)           __libc_mutex_lock((m))
 150 #define mutex_trylock(m)        __libc_mutex_trylock((m))
 151 #define mutex_unlock(m)         __libc_mutex_unlock((m))
 152 #define mutex_destroy(m)        __libc_mutex_destroy((m))
 153
 154 #define mutexattr_init(ma)      __libc_mutexattr_init((ma))
 155 #define mutexattr_settype(ma, t) __libc_mutexattr_settype((ma), (t))
 156 #define mutexattr_destroy(ma)   __libc_mutexattr_destroy((ma))
 157
 158 __BEGIN_DECLS
 159 int     __libc_cond_init(cond_t *, const condattr_t *);
 160 int     __libc_cond_signal(cond_t *);
 161 int     __libc_cond_broadcast(cond_t *);
 162 int     __libc_cond_wait(cond_t *, mutex_t *);
 163 int     __libc_cond_timedwait(cond_t *, mutex_t *, const struct timespec *);
 164 int     __libc_cond_destroy(cond_t *);
 165 __END_DECLS
 166
 167 #define cond_init(c, t, a)      __libc_cond_init((c), (a))
 168 #define cond_signal(c)          __libc_cond_signal((c))
 169 #define cond_broadcast(c)       __libc_cond_broadcast((c))
 170 #define cond_wait(c, m)         __libc_cond_wait((c), (m))
 171 #define cond_timedwait(c, m, t) __libc_cond_timedwait((c), (m), (t))
 172 #define cond_destroy(c)         __libc_cond_destroy((c))
 173
 174 __BEGIN_DECLS
 175 int     __libc_rwlock_init(rwlock_t *, const rwlockattr_t *);
 176 int     __libc_rwlock_rdlock(rwlock_t *);
 177 int     __libc_rwlock_wrlock(rwlock_t *);
 178 int     __libc_rwlock_tryrdlock(rwlock_t *);
 179 int     __libc_rwlock_trywrlock(rwlock_t *);
 180 int     __libc_rwlock_unlock(rwlock_t *);
 181 int     __libc_rwlock_destroy(rwlock_t *);
 182 __END_DECLS
 183
 184 #define rwlock_init(l, a)       __libc_rwlock_init((l), (a))
 185 #define rwlock_rdlock(l)        __libc_rwlock_rdlock((l))
 186 #define rwlock_wrlock(l)        __libc_rwlock_wrlock((l))
 187 #define rwlock_tryrdlock(l)     __libc_rwlock_tryrdlock((l))
 188 #define rwlock_trywrlock(l)     __libc_rwlock_trywrlock((l))
 189 #define rwlock_unlock(l)        __libc_rwlock_unlock((l))
 190 #define rwlock_destroy(l)       __libc_rwlock_destroy((l))
 191
 192 __BEGIN_DECLS
 193 int     __libc_thr_keycreate(thread_key_t *, void (*)(void *));
 194 int     __libc_thr_setspecific(thread_key_t, const void *);
 195 void    *__libc_thr_getspecific(thread_key_t);
 196 int     __libc_thr_keydelete(thread_key_t);
 197 __END_DECLS
 198
 199 #define thr_keycreate(k, d)     __libc_thr_keycreate((k), (d))
 200 #define thr_setspecific(k, p)   __libc_thr_setspecific((k), (p))
 201 #define thr_getspecific(k)      __libc_thr_getspecific((k))
 202 #define thr_keydelete(k)        __libc_thr_keydelete((k))
 203
 204 __BEGIN_DECLS
 205 int     __libc_thr_once(once_t *, void (*)(void));
 206 int     __libc_thr_sigsetmask(int, const sigset_t *, sigset_t *);
 207 thr_t   __libc_thr_self(void);
 208 int     __libc_thr_yield(void);
 209 void    __libc_thr_create(thr_t *, const thrattr_t *,
 210             void *(*)(void *), void *);
 211 void    __libc_thr_exit(void *) __attribute__((__noreturn__));
 212 int     *__libc_thr_errno(void);
 213 int     __libc_thr_setcancelstate(int, int *);
 214
 215 extern int __isthreaded;
 216 __END_DECLS
 217
 218 #define thr_once(o, f)          __libc_thr_once((o), (f))
 219 #define thr_sigsetmask(f, n, o) __libc_thr_sigsetmask((f), (n), (o))
 220 #define thr_self()              __libc_thr_self()
 221 #define thr_yield()             __libc_thr_yield()
 222 #define thr_create(tp, ta, f, a) __libc_thr_create((tp), (ta), (f), (a))
 223 #define thr_exit(v)             __libc_thr_exit((v))
 224 #define thr_errno()             __libc_thr_errno()
 225 #define thr_enabled()           (__isthreaded)
 226 #define thr_setcancelstate(n, o) __libc_thr_setcancelstate((n),(o))
 227 #endif /* __LIBC_THREAD_STUBS */
 228
 229 #define FLOCKFILE(fp)           __flockfile_internal(fp, 1)
 230 #define FUNLOCKFILE(fp)         __funlockfile_internal(fp, 1)
 231
 232 #else /* _REENTRANT */
 233
 234 #define mutex_init(m, a)
 235 #define mutex_lock(m)
 236 #define mutex_trylock(m)
 237 #define mutex_unlock(m)
 238 #define mutex_destroy(m)
 239
 240 #define cond_init(c, t, a)
 241 #define cond_signal(c)
 242 #define cond_broadcast(c)
 243 #define cond_wait(c, m)
 244 #define cond_timedwait(c, m, t)
 245 #define cond_destroy(c)
 246
 247 #define rwlock_init(l, a)
 248 #define rwlock_rdlock(l)
 249 #define rwlock_wrlock(l)
 250 #define rwlock_tryrdlock(l)
 251 #define rwlock_trywrlock(l)
 252 #define rwlock_unlock(l)
 253 #define rwlock_destroy(l)
 254
 255 #define thr_keycreate(k, d)
 256 #define thr_setspecific(k, p)
 257 #define thr_getspecific(k)
 258 #define thr_keydelete(k)
 259
 260 #define thr_once(o, f)
 261 #define thr_sigsetmask(f, n, o)
 262 #define thr_self()
 263 #define thr_errno()
 264
 265 #define FLOCKFILE(fp)
 266 #define FUNLOCKFILE(fp)
 267
 268 #endif /* _REENTRANT */