[1b13f69] | 1 | /*- |
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| 2 | * Copyright (c) 1997,98 The NetBSD Foundation, Inc. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * This code is derived from software contributed to The NetBSD Foundation |
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| 6 | * by J.T. Conklin. |
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| 7 | * |
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| 8 | * Redistribution and use in source and binary forms, with or without |
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| 9 | * modification, are permitted provided that the following conditions |
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| 10 | * are met: |
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| 11 | * 1. Redistributions of source code must retain the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer. |
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 14 | * notice, this list of conditions and the following disclaimer in the |
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| 15 | * documentation and/or other materials provided with the distribution. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
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| 18 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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| 19 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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| 20 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
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| 21 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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| 22 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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| 23 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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| 24 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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| 25 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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| 26 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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| 27 | * POSSIBILITY OF SUCH DAMAGE. |
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| 28 | * |
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| 29 | * $FreeBSD$ |
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| 30 | */ |
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| 31 | |
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| 32 | /* |
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| 33 | * Requirements: |
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| 34 | * |
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| 35 | * 1. The thread safe mechanism should be lightweight so the library can |
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| 36 | * be used by non-threaded applications without unreasonable overhead. |
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| 37 | * |
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| 38 | * 2. There should be no dependency on a thread engine for non-threaded |
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| 39 | * applications. |
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| 40 | * |
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| 41 | * 3. There should be no dependency on any particular thread engine. |
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| 42 | * |
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| 43 | * 4. The library should be able to be compiled without support for thread |
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| 44 | * safety. |
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| 45 | * |
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| 46 | * |
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| 47 | * Rationale: |
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| 48 | * |
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| 49 | * One approach for thread safety is to provide discrete versions of the |
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| 50 | * library: one thread safe, the other not. The disadvantage of this is |
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| 51 | * that libc is rather large, and two copies of a library which are 99%+ |
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| 52 | * identical is not an efficent use of resources. |
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| 53 | * |
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| 54 | * Another approach is to provide a single thread safe library. However, |
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| 55 | * it should not add significant run time or code size overhead to non- |
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| 56 | * threaded applications. |
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| 57 | * |
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| 58 | * Since the NetBSD C library is used in other projects, it should be |
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| 59 | * easy to replace the mutual exclusion primitives with ones provided by |
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| 60 | * another system. Similarly, it should also be easy to remove all |
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| 61 | * support for thread safety completely if the target environment does |
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| 62 | * not support threads. |
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| 63 | * |
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| 64 | * |
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| 65 | * Implementation Details: |
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| 66 | * |
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| 67 | * The mutex primitives used by the library (mutex_t, mutex_lock, etc.) |
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| 68 | * are macros which expand to the cooresponding primitives provided by |
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| 69 | * the thread engine or to nothing. The latter is used so that code is |
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| 70 | * not unreasonably cluttered with #ifdefs when all thread safe support |
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| 71 | * is removed. |
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| 72 | * |
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| 73 | * The mutex macros can be directly mapped to the mutex primitives from |
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| 74 | * pthreads, however it should be reasonably easy to wrap another mutex |
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| 75 | * implementation so it presents a similar interface. |
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| 76 | * |
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| 77 | * Stub implementations of the mutex functions are provided with *weak* |
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| 78 | * linkage. These functions simply return success. When linked with a |
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| 79 | * thread library (i.e. -lpthread), the functions will override the |
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| 80 | * stubs. |
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| 81 | */ |
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| 82 | |
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| 83 | #include <pthread.h> |
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| 84 | #include <pthread_np.h> |
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| 85 | #include "libc_private.h" |
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| 86 | |
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| 87 | #define mutex_t pthread_mutex_t |
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| 88 | #define cond_t pthread_cond_t |
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| 89 | #define rwlock_t pthread_rwlock_t |
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| 90 | #define once_t pthread_once_t |
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| 91 | |
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| 92 | #define thread_key_t pthread_key_t |
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| 93 | #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER |
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| 94 | #define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER |
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| 95 | #define ONCE_INITIALIZER PTHREAD_ONCE_INIT |
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| 96 | |
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| 97 | #define mutex_init(m, a) _pthread_mutex_init(m, a) |
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| 98 | #define mutex_lock(m) if (__isthreaded) \ |
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| 99 | _pthread_mutex_lock(m) |
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| 100 | #define mutex_unlock(m) if (__isthreaded) \ |
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| 101 | _pthread_mutex_unlock(m) |
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| 102 | #define mutex_trylock(m) (__isthreaded ? 0 : _pthread_mutex_trylock(m)) |
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| 103 | |
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| 104 | #define cond_init(c, a, p) _pthread_cond_init(c, a) |
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| 105 | #define cond_signal(m) if (__isthreaded) \ |
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| 106 | _pthread_cond_signal(m) |
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| 107 | #define cond_broadcast(m) if (__isthreaded) \ |
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| 108 | _pthread_cond_broadcast(m) |
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| 109 | #define cond_wait(c, m) if (__isthreaded) \ |
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| 110 | _pthread_cond_wait(c, m) |
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| 111 | |
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| 112 | #define rwlock_init(l, a) _pthread_rwlock_init(l, a) |
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| 113 | #define rwlock_rdlock(l) if (__isthreaded) \ |
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| 114 | _pthread_rwlock_rdlock(l) |
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| 115 | #define rwlock_wrlock(l) if (__isthreaded) \ |
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| 116 | _pthread_rwlock_wrlock(l) |
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| 117 | #define rwlock_unlock(l) if (__isthreaded) \ |
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| 118 | _pthread_rwlock_unlock(l) |
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| 119 | |
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| 120 | #define thr_keycreate(k, d) _pthread_key_create(k, d) |
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| 121 | #define thr_setspecific(k, p) _pthread_setspecific(k, p) |
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| 122 | #define thr_getspecific(k) _pthread_getspecific(k) |
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| 123 | #define thr_sigsetmask(f, n, o) _pthread_sigmask(f, n, o) |
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| 124 | |
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| 125 | #define thr_once(o, i) _pthread_once(o, i) |
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| 126 | #define thr_self() _pthread_self() |
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| 127 | #define thr_exit(x) _pthread_exit(x) |
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| 128 | #define thr_main() _pthread_main_np() |
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