1/* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "apr_arch_atomic.h" 18#include "apr_thread_mutex.h" 19 20#ifdef USE_ATOMICS_GENERIC 21 22#include <stdlib.h> 23 24#if APR_HAS_THREADS 25# define DECLARE_MUTEX_LOCKED(name, mem) \ 26 apr_thread_mutex_t *name = mutex_hash(mem) 27# define MUTEX_UNLOCK(name) \ 28 do { \ 29 if (apr_thread_mutex_unlock(name) != APR_SUCCESS) \ 30 abort(); \ 31 } while (0) 32#else 33# define DECLARE_MUTEX_LOCKED(name, mem) 34# define MUTEX_UNLOCK(name) 35# warning Be warned: using stubs for all atomic operations 36#endif 37 38#if APR_HAS_THREADS 39 40static apr_thread_mutex_t **hash_mutex; 41 42#define NUM_ATOMIC_HASH 7 43/* shift by 2 to get rid of alignment issues */ 44#define ATOMIC_HASH(x) (unsigned int)(((unsigned long)(x)>>2)%(unsigned int)NUM_ATOMIC_HASH) 45 46static apr_status_t atomic_cleanup(void *data) 47{ 48 if (hash_mutex == data) 49 hash_mutex = NULL; 50 51 return APR_SUCCESS; 52} 53 54APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p) 55{ 56 int i; 57 apr_status_t rv; 58 59 if (hash_mutex != NULL) 60 return APR_SUCCESS; 61 62 hash_mutex = apr_palloc(p, sizeof(apr_thread_mutex_t*) * NUM_ATOMIC_HASH); 63 apr_pool_cleanup_register(p, hash_mutex, atomic_cleanup, 64 apr_pool_cleanup_null); 65 66 for (i = 0; i < NUM_ATOMIC_HASH; i++) { 67 rv = apr_thread_mutex_create(&(hash_mutex[i]), 68 APR_THREAD_MUTEX_DEFAULT, p); 69 if (rv != APR_SUCCESS) { 70 return rv; 71 } 72 } 73 74 return apr__atomic_generic64_init(p); 75} 76 77static APR_INLINE apr_thread_mutex_t *mutex_hash(volatile apr_uint32_t *mem) 78{ 79 apr_thread_mutex_t *mutex = hash_mutex[ATOMIC_HASH(mem)]; 80 81 if (apr_thread_mutex_lock(mutex) != APR_SUCCESS) { 82 abort(); 83 } 84 85 return mutex; 86} 87 88#else 89 90APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p) 91{ 92 return apr__atomic_generic64_init(p); 93} 94 95#endif /* APR_HAS_THREADS */ 96 97APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem) 98{ 99 return *mem; 100} 101 102APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val) 103{ 104 DECLARE_MUTEX_LOCKED(mutex, mem); 105 106 *mem = val; 107 108 MUTEX_UNLOCK(mutex); 109} 110 111APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val) 112{ 113 apr_uint32_t old_value; 114 DECLARE_MUTEX_LOCKED(mutex, mem); 115 116 old_value = *mem; 117 *mem += val; 118 119 MUTEX_UNLOCK(mutex); 120 121 return old_value; 122} 123 124APR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val) 125{ 126 DECLARE_MUTEX_LOCKED(mutex, mem); 127 *mem -= val; 128 MUTEX_UNLOCK(mutex); 129} 130 131APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem) 132{ 133 return apr_atomic_add32(mem, 1); 134} 135 136APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem) 137{ 138 apr_uint32_t new; 139 DECLARE_MUTEX_LOCKED(mutex, mem); 140 141 (*mem)--; 142 new = *mem; 143 144 MUTEX_UNLOCK(mutex); 145 146 return new; 147} 148 149APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with, 150 apr_uint32_t cmp) 151{ 152 apr_uint32_t prev; 153 DECLARE_MUTEX_LOCKED(mutex, mem); 154 155 prev = *mem; 156 if (prev == cmp) { 157 *mem = with; 158 } 159 160 MUTEX_UNLOCK(mutex); 161 162 return prev; 163} 164 165APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val) 166{ 167 apr_uint32_t prev; 168 DECLARE_MUTEX_LOCKED(mutex, mem); 169 170 prev = *mem; 171 *mem = val; 172 173 MUTEX_UNLOCK(mutex); 174 175 return prev; 176} 177 178APR_DECLARE(void*) apr_atomic_casptr(volatile void **mem, void *with, const void *cmp) 179{ 180 void *prev; 181 DECLARE_MUTEX_LOCKED(mutex, *mem); 182 183 prev = *(void **)mem; 184 if (prev == cmp) { 185 *mem = with; 186 } 187 188 MUTEX_UNLOCK(mutex); 189 190 return prev; 191} 192 193APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem, void *with) 194{ 195 void *prev; 196 DECLARE_MUTEX_LOCKED(mutex, *mem); 197 198 prev = *(void **)mem; 199 *mem = with; 200 201 MUTEX_UNLOCK(mutex); 202 203 return prev; 204} 205 206#endif /* USE_ATOMICS_GENERIC */ 207