| 1 | /* |
| 2 | * Copyright (c) 2006-2008 Amit Singh/Google Inc. |
| 3 | * Copyright (c) 2012 Anatol Pomozov |
| 4 | * Copyright (c) 2011-2013 Benjamin Fleischer |
| 5 | */ |
| 6 | |
| 7 | #include "darwin_compat.h" |
| 8 | |
| 9 | #include <assert.h> |
| 10 | #include <errno.h> |
| 11 | #include <sys/types.h> |
| 12 | |
| 13 | /* |
| 14 | * Semaphore implementation based on: |
| 15 | * |
| 16 | * Copyright (C) 2000,02 Free Software Foundation, Inc. |
| 17 | * This file is part of the GNU C Library. |
| 18 | * Written by Ga<EB>l Le Mignot <address@hidden> |
| 19 | * |
| 20 | * The GNU C Library is free software; you can redistribute it and/or |
| 21 | * modify it under the terms of the GNU Library General Public License as |
| 22 | * published by the Free Software Foundation; either version 2 of the |
| 23 | * License, or (at your option) any later version. |
| 24 | * |
| 25 | * The GNU C Library is distributed in the hope that it will be useful, |
| 26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 28 | * Library General Public License for more details. |
| 29 | * |
| 30 | * You should have received a copy of the GNU Library General Public |
| 31 | * License along with the GNU C Library; see the file COPYING.LIB. If not, |
| 32 | * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 33 | * Boston, MA 02111-1307, USA. |
| 34 | */ |
| 35 | |
| 36 | /* Semaphores */ |
| 37 | |
| 38 | #define __SEM_ID_NONE ((int)0x0) |
| 39 | #define __SEM_ID_LOCAL ((int)0xcafef00d) |
| 40 | |
| 41 | /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_init.html */ |
| 42 | int |
| 43 | darwin_sem_init(darwin_sem_t *sem, int pshared, unsigned int value) |
| 44 | { |
| 45 | if (pshared) { |
| 46 | errno = ENOSYS; |
| 47 | return -1; |
| 48 | } |
| 49 | |
| 50 | sem->id = __SEM_ID_NONE; |
| 51 | |
| 52 | if (pthread_cond_init(&sem->__data.local.count_cond, NULL)) { |
| 53 | goto cond_init_fail; |
| 54 | } |
| 55 | |
| 56 | if (pthread_mutex_init(&sem->__data.local.count_lock, NULL)) { |
| 57 | goto mutex_init_fail; |
| 58 | } |
| 59 | |
| 60 | sem->__data.local.count = value; |
| 61 | sem->id = __SEM_ID_LOCAL; |
| 62 | |
| 63 | return 0; |
| 64 | |
| 65 | mutex_init_fail: |
| 66 | |
| 67 | pthread_cond_destroy(&sem->__data.local.count_cond); |
| 68 | |
| 69 | cond_init_fail: |
| 70 | |
| 71 | return -1; |
| 72 | } |
| 73 | |
| 74 | /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_destroy.html */ |
| 75 | int |
| 76 | darwin_sem_destroy(darwin_sem_t *sem) |
| 77 | { |
| 78 | int res = 0; |
| 79 | |
| 80 | pthread_mutex_lock(&sem->__data.local.count_lock); |
| 81 | |
| 82 | sem->id = __SEM_ID_NONE; |
| 83 | pthread_cond_broadcast(&sem->__data.local.count_cond); |
| 84 | |
| 85 | if (pthread_cond_destroy(&sem->__data.local.count_cond)) { |
| 86 | res = -1; |
| 87 | } |
| 88 | |
| 89 | pthread_mutex_unlock(&sem->__data.local.count_lock); |
| 90 | |
| 91 | if (pthread_mutex_destroy(&sem->__data.local.count_lock)) { |
| 92 | res = -1; |
| 93 | } |
| 94 | |
| 95 | return res; |
| 96 | } |
| 97 | |
| 98 | int |
| 99 | darwin_sem_getvalue(darwin_sem_t *sem, unsigned int *sval) |
| 100 | { |
| 101 | int res = 0; |
| 102 | |
| 103 | pthread_mutex_lock(&sem->__data.local.count_lock); |
| 104 | |
| 105 | if (sem->id != __SEM_ID_LOCAL) { |
| 106 | res = -1; |
| 107 | errno = EINVAL; |
| 108 | } else { |
| 109 | *sval = sem->__data.local.count; |
| 110 | } |
| 111 | |
| 112 | pthread_mutex_unlock(&sem->__data.local.count_lock); |
| 113 | |
| 114 | return res; |
| 115 | } |
| 116 | |
| 117 | /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_post.html */ |
| 118 | int |
| 119 | darwin_sem_post(darwin_sem_t *sem) |
| 120 | { |
| 121 | int res = 0; |
| 122 | |
| 123 | pthread_mutex_lock(&sem->__data.local.count_lock); |
| 124 | |
| 125 | if (sem->id != __SEM_ID_LOCAL) { |
| 126 | res = -1; |
| 127 | errno = EINVAL; |
| 128 | } else if (sem->__data.local.count < DARWIN_SEM_VALUE_MAX) { |
| 129 | sem->__data.local.count++; |
| 130 | if (sem->__data.local.count == 1) { |
| 131 | pthread_cond_signal(&sem->__data.local.count_cond); |
| 132 | } |
| 133 | } else { |
| 134 | errno = ERANGE; |
| 135 | res = -1; |
| 136 | } |
| 137 | |
| 138 | pthread_mutex_unlock(&sem->__data.local.count_lock); |
| 139 | |
| 140 | return res; |
| 141 | } |
| 142 | |
| 143 | /* http://www.opengroup.org/onlinepubs/009695399/functions/sem_timedwait.html */ |
| 144 | int |
| 145 | darwin_sem_timedwait(darwin_sem_t *sem, const struct timespec *abs_timeout) |
| 146 | { |
| 147 | int res = 0; |
| 148 | |
| 149 | if (abs_timeout && |
| 150 | (abs_timeout->tv_nsec < 0 || abs_timeout->tv_nsec >= 1000000000)) { |
| 151 | errno = EINVAL; |
| 152 | return -1; |
| 153 | } |
| 154 | |
| 155 | pthread_cleanup_push((void(*)(void*))&pthread_mutex_unlock, |
| 156 | &sem->__data.local.count_lock); |
| 157 | |
| 158 | pthread_mutex_lock(&sem->__data.local.count_lock); |
| 159 | |
| 160 | if (sem->id != __SEM_ID_LOCAL) { |
| 161 | errno = EINVAL; |
| 162 | res = -1; |
| 163 | } else { |
| 164 | if (!sem->__data.local.count) { |
| 165 | res = pthread_cond_timedwait(&sem->__data.local.count_cond, |
| 166 | &sem->__data.local.count_lock, |
| 167 | abs_timeout); |
| 168 | } |
| 169 | if (res) { |
| 170 | assert(res == ETIMEDOUT); |
| 171 | res = -1; |
| 172 | errno = ETIMEDOUT; |
| 173 | } else if (sem->id != __SEM_ID_LOCAL) { |
| 174 | res = -1; |
| 175 | errno = EINVAL; |
| 176 | } else { |
| 177 | sem->__data.local.count--; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | pthread_cleanup_pop(1); |
| 182 | |
| 183 | return res; |
| 184 | } |
| 185 | |
| 186 | /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_trywait.html */ |
| 187 | int |
| 188 | darwin_sem_trywait(darwin_sem_t *sem) |
| 189 | { |
| 190 | int res = 0; |
| 191 | |
| 192 | pthread_mutex_lock(&sem->__data.local.count_lock); |
| 193 | |
| 194 | if (sem->id != __SEM_ID_LOCAL) { |
| 195 | res = -1; |
| 196 | errno = EINVAL; |
| 197 | } else if (sem->__data.local.count) { |
| 198 | sem->__data.local.count--; |
| 199 | } else { |
| 200 | res = -1; |
| 201 | errno = EAGAIN; |
| 202 | } |
| 203 | |
| 204 | pthread_mutex_unlock (&sem->__data.local.count_lock); |
| 205 | |
| 206 | return res; |
| 207 | } |
| 208 | |
| 209 | /* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_wait.html */ |
| 210 | int |
| 211 | darwin_sem_wait(darwin_sem_t *sem) |
| 212 | { |
| 213 | int res = 0; |
| 214 | |
| 215 | pthread_cleanup_push((void(*)(void*))&pthread_mutex_unlock, |
| 216 | &sem->__data.local.count_lock); |
| 217 | |
| 218 | pthread_mutex_lock(&sem->__data.local.count_lock); |
| 219 | |
| 220 | if (sem->id != __SEM_ID_LOCAL) { |
| 221 | errno = EINVAL; |
| 222 | res = -1; |
| 223 | } else { |
| 224 | if (!sem->__data.local.count) { |
| 225 | pthread_cond_wait(&sem->__data.local.count_cond, |
| 226 | &sem->__data.local.count_lock); |
| 227 | if (!sem->__data.local.count) { |
| 228 | /* spurious wakeup, assume it is an interruption */ |
| 229 | res = -1; |
| 230 | errno = EINTR; |
| 231 | goto out; |
| 232 | } |
| 233 | } |
| 234 | if (sem->id != __SEM_ID_LOCAL) { |
| 235 | res = -1; |
| 236 | errno = EINVAL; |
| 237 | } else { |
| 238 | sem->__data.local.count--; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | out: |
| 243 | pthread_cleanup_pop(1); |
| 244 | |
| 245 | return res; |
| 246 | } |