1 | /*- |
---|
2 | * Copyright (c) 1997,98 The NetBSD Foundation, Inc. |
---|
3 | * All rights reserved. |
---|
4 | * |
---|
5 | * This code is derived from software contributed to The NetBSD Foundation |
---|
6 | * by J.T. Conklin. |
---|
7 | * |
---|
8 | * Redistribution and use in source and binary forms, with or without |
---|
9 | * modification, are permitted provided that the following conditions |
---|
10 | * are met: |
---|
11 | * 1. Redistributions of source code must retain the above copyright |
---|
12 | * notice, this list of conditions and the following disclaimer. |
---|
13 | * 2. Redistributions in binary form must reproduce the above copyright |
---|
14 | * notice, this list of conditions and the following disclaimer in the |
---|
15 | * documentation and/or other materials provided with the distribution. |
---|
16 | * |
---|
17 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
---|
18 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
---|
19 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
---|
20 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
---|
21 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
---|
22 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
---|
23 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
---|
24 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
---|
25 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
---|
26 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
---|
27 | * POSSIBILITY OF SUCH DAMAGE. |
---|
28 | * |
---|
29 | * $FreeBSD$ |
---|
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 mutex 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 mutex 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 | * Stub implementations of the mutex functions are provided with *weak* |
---|
78 | * linkage. These functions simply return success. When linked with a |
---|
79 | * thread library (i.e. -lpthread), the functions will override the |
---|
80 | * stubs. |
---|
81 | */ |
---|
82 | |
---|
83 | #include <pthread.h> |
---|
84 | #include <pthread_np.h> |
---|
85 | #include "libc_private.h" |
---|
86 | |
---|
87 | #define mutex_t pthread_mutex_t |
---|
88 | #define cond_t pthread_cond_t |
---|
89 | #define rwlock_t pthread_rwlock_t |
---|
90 | #define once_t pthread_once_t |
---|
91 | |
---|
92 | #define thread_key_t pthread_key_t |
---|
93 | #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER |
---|
94 | #define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER |
---|
95 | #define ONCE_INITIALIZER PTHREAD_ONCE_INIT |
---|
96 | |
---|
97 | #define mutex_init(m, a) _pthread_mutex_init(m, a) |
---|
98 | #define mutex_lock(m) if (__isthreaded) \ |
---|
99 | _pthread_mutex_lock(m) |
---|
100 | #define mutex_unlock(m) if (__isthreaded) \ |
---|
101 | _pthread_mutex_unlock(m) |
---|
102 | #define mutex_trylock(m) (__isthreaded ? 0 : _pthread_mutex_trylock(m)) |
---|
103 | |
---|
104 | #define cond_init(c, a, p) _pthread_cond_init(c, a) |
---|
105 | #define cond_signal(m) if (__isthreaded) \ |
---|
106 | _pthread_cond_signal(m) |
---|
107 | #define cond_broadcast(m) if (__isthreaded) \ |
---|
108 | _pthread_cond_broadcast(m) |
---|
109 | #define cond_wait(c, m) if (__isthreaded) \ |
---|
110 | _pthread_cond_wait(c, m) |
---|
111 | |
---|
112 | #define rwlock_init(l, a) _pthread_rwlock_init(l, a) |
---|
113 | #define rwlock_rdlock(l) if (__isthreaded) \ |
---|
114 | _pthread_rwlock_rdlock(l) |
---|
115 | #define rwlock_wrlock(l) if (__isthreaded) \ |
---|
116 | _pthread_rwlock_wrlock(l) |
---|
117 | #define rwlock_unlock(l) if (__isthreaded) \ |
---|
118 | _pthread_rwlock_unlock(l) |
---|
119 | |
---|
120 | #define thr_keycreate(k, d) _pthread_key_create(k, d) |
---|
121 | #define thr_setspecific(k, p) _pthread_setspecific(k, p) |
---|
122 | #define thr_getspecific(k) _pthread_getspecific(k) |
---|
123 | #define thr_sigsetmask(f, n, o) _pthread_sigmask(f, n, o) |
---|
124 | |
---|
125 | #define thr_once(o, i) _pthread_once(o, i) |
---|
126 | #define thr_self() _pthread_self() |
---|
127 | #define thr_exit(x) _pthread_exit(x) |
---|
128 | #define thr_main() _pthread_main_np() |
---|