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256
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@devolution.com
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 #include <stdlib.h>
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29 #include "SDL_error.h"
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30 #include "SDL_thread.h"
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31 #include "SDL_timer.h"
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32
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33 #ifdef SDL_USE_PTHREADS
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34
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35 #include <stdio.h>
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36 #include <stdlib.h>
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37 #include <unistd.h> /* For getpid() */
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38 #include <pthread.h>
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39
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40
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41 /*
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42 * This is semaphore.h inlined here so that BSD/OS POSIX semaphore are
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43 * completely selfcontained without requiring any additional include files
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44 * or libraries not present in the stock system
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45 */
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46
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47 /* semaphore.h: POSIX 1003.1b semaphores */
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48
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49 /*-
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50 * Copyright (c) 1996, 1997
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51 * HD Associates, Inc. All rights reserved.
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52 *
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53 * Redistribution and use in source and binary forms, with or without
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54 * modification, are permitted provided that the following conditions
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55 * are met:
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56 * 1. Redistributions of source code must retain the above copyright
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57 * notice, this list of conditions and the following disclaimer.
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58 * 2. Redistributions in binary form must reproduce the above copyright
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59 * notice, this list of conditions and the following disclaimer in the
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60 * documentation and/or other materials provided with the distribution.
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61 * 3. All advertising materials mentioning features or use of this software
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62 * must display the following acknowledgement:
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63 * This product includes software developed by HD Associates, Inc
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64 * 4. Neither the name of the author nor the names of any co-contributors
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65 * may be used to endorse or promote products derived from this software
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66 * without specific prior written permission.
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67 *
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68 * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
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69 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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70 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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71 * ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
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72 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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73 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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74 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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75 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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76 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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77 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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78 * SUCH DAMAGE.
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79 *
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80 * $FreeBSD: src/sys/posix4/semaphore.h,v 1.6 2000/01/20 07:55:42 jasone Exp $
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81 */
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82
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83 #include <machine/limits.h>
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84
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85 #include <sys/types.h>
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86 #include <fcntl.h>
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87
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88 /* Opaque type definition. */
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89 struct sem;
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90 typedef struct sem *sem_t;
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91
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92 #define SEM_FAILED ((sem_t *)0)
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93 #define SEM_VALUE_MAX UINT_MAX
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94
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95 #include <sys/cdefs.h>
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96
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97 __BEGIN_DECLS
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98 int sem_init __P((sem_t *, int, unsigned int));
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99 int sem_destroy __P((sem_t *));
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100 sem_t *sem_open __P((const char *, int, ...));
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101 int sem_close __P((sem_t *));
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102 int sem_unlink __P((const char *));
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103 int sem_wait __P((sem_t *));
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104 int sem_trywait __P((sem_t *));
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105 int sem_post __P((sem_t *));
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106 int sem_getvalue __P((sem_t *, int *));
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107 __END_DECLS
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108
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109 /* END of inlined semaphore.h */
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110
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111 /* Wrapper around POSIX 1003.1b semaphores */
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112
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113 struct SDL_semaphore {
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114 sem_t *sem;
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115 sem_t sem_data;
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116 };
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117
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118 /* Create a semaphore, initialized with value */
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119 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
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120 {
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121 SDL_sem *sem = (SDL_sem *) malloc(sizeof(SDL_sem));
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122 if ( sem ) {
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123 if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) {
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124 SDL_SetError("sem_init() failed");
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125 free(sem);
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126 sem = NULL;
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127 } else {
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128 sem->sem = &sem->sem_data;
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129 }
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130 } else {
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131 SDL_OutOfMemory();
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132 }
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133 return sem;
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134 }
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135
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136 void SDL_DestroySemaphore(SDL_sem *sem)
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137 {
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138 if ( sem ) {
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139 sem_destroy(sem->sem);
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140 free(sem);
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141 }
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142 }
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143
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144 int SDL_SemTryWait(SDL_sem *sem)
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145 {
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146 int retval;
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147
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148 if ( ! sem ) {
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149 SDL_SetError("Passed a NULL semaphore");
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150 return -1;
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151 }
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152 retval = SDL_MUTEX_TIMEDOUT;
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153 if ( sem_trywait(sem->sem) == 0 )
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154 retval = 0;
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155 return retval;
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156 }
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157
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158 int SDL_SemWait(SDL_sem *sem)
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159 {
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160 int retval;
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161
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162 if ( ! sem ) {
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163 SDL_SetError("Passed a NULL semaphore");
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164 return -1;
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165 }
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166
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167 retval = sem_wait(sem->sem);
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168 if ( retval < 0 ) {
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169 SDL_SetError("sem_wait() failed");
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170 }
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171 return retval;
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172 }
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173
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174 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
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175 {
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176 int retval;
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177
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178 if ( ! sem ) {
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179 SDL_SetError("Passed a NULL semaphore");
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180 return -1;
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181 }
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182
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183 /* Try the easy cases first */
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184 if ( timeout == 0 ) {
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185 return SDL_SemTryWait(sem);
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186 }
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187 if ( timeout == SDL_MUTEX_MAXWAIT ) {
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188 return SDL_SemWait(sem);
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189 }
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190
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191 /* Ack! We have to busy wait... */
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192 timeout += SDL_GetTicks();
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193 do {
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194 retval = SDL_SemTryWait(sem);
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195 if ( retval == 0 ) {
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196 break;
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197 }
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198 SDL_Delay(1);
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199 } while ( SDL_GetTicks() < timeout );
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200
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201 return retval;
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202 }
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203
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204 Uint32 SDL_SemValue(SDL_sem *sem)
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205 {
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206 int ret = 0;
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207 if ( sem ) {
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208 sem_getvalue(sem->sem, &ret);
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209 if ( ret < 0 ) {
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210 ret = 0;
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211 }
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212 }
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213 return (Uint32)ret;
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214 }
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215
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216 int SDL_SemPost(SDL_sem *sem)
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217 {
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218 int retval;
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219
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220 if ( ! sem ) {
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221 SDL_SetError("Passed a NULL semaphore");
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222 return -1;
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223 }
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224
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225 retval = sem_post(sem->sem);
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226 if ( retval < 0 ) {
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227 SDL_SetError("sem_post() failed");
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228 }
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229 return retval;
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230 }
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231
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232 /*
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233 * BEGIN inlined uthread_sem.c. This is done here so that no extra libraries
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234 * or include files not present in BSD/OS are required
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235 */
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236
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237 /*
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238 * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
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239 * All rights reserved.
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240 *
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241 * Redistribution and use in source and binary forms, with or without
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242 * modification, are permitted provided that the following conditions
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243 * are met:
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244 * 1. Redistributions of source code must retain the above copyright
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|
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245 * notice(s), this list of conditions and the following disclaimer as
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246 * the first lines of this file unmodified other than the possible
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247 * addition of one or more copyright notices.
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248 * 2. Redistributions in binary form must reproduce the above copyright
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249 * notice(s), this list of conditions and the following disclaimer in
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250 * the documentation and/or other materials provided with the
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251 * distribution.
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252 *
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253 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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254 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
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255 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
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256 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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257 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
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258 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
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259 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
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260 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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261 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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262 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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263 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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264 *
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265 * $FreeBSD: src/lib/libc_r/uthread/uthread_sem.c,v 1.3.2.1 2000/07/18 02:05:57 jasone Exp $
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266 */
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267
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268 #include <errno.h>
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269 #include <pthread.h>
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270
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271 /* Begin thread_private.h kluge */
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272 /*
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273 * These come out of (or should go into) thread_private.h - rather than have
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274 * to copy (or symlink) the files from the source tree these definitions are
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275 * inlined here. Obviously these go away when this module is part of libc.
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276 */
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277 struct sem {
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278 #define SEM_MAGIC ((u_int32_t) 0x09fa4012)
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279 u_int32_t magic;
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280 pthread_mutex_t lock;
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281 pthread_cond_t gtzero;
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282 u_int32_t count;
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283 u_int32_t nwaiters;
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284 };
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285
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286 extern pthread_once_t _thread_init_once;
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287 extern int _threads_initialized;
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288 extern void _thread_init __P((void));
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289 #define THREAD_INIT() \
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290 (void) pthread_once(&_thread_init_once, _thread_init)
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291 #define THREAD_SAFE() \
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292 (_threads_initialized != 0)
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293
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294 #define _SEM_CHECK_VALIDITY(sem) \
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295 if ((*(sem))->magic != SEM_MAGIC) { \
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296 errno = EINVAL; \
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297 retval = -1; \
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298 goto RETURN; \
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299 }
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300 /* End thread_private.h kluge */
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301
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302 int
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303 sem_init(sem_t *sem, int pshared, unsigned int value)
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304 {
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305 int retval;
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306
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307 if (!THREAD_SAFE())
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308 THREAD_INIT();
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309
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310 /*
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311 * Range check the arguments.
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312 */
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313 if (pshared != 0) {
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314 /*
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315 * The user wants a semaphore that can be shared among
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316 * processes, which this implementation can't do. Sounds like a
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317 * permissions problem to me (yeah right).
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318 */
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319 errno = EPERM;
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320 retval = -1;
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321 goto RETURN;
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322 }
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323
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324 if (value > SEM_VALUE_MAX) {
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325 errno = EINVAL;
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326 retval = -1;
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327 goto RETURN;
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328 }
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329
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330 *sem = (sem_t)malloc(sizeof(struct sem));
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331 if (*sem == NULL) {
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332 errno = ENOSPC;
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333 retval = -1;
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334 goto RETURN;
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335 }
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336
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337 /*
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338 * Initialize the semaphore.
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339 */
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340 if (pthread_mutex_init(&(*sem)->lock, NULL) != 0) {
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341 free(*sem);
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342 errno = ENOSPC;
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343 retval = -1;
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344 goto RETURN;
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345 }
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346
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347 if (pthread_cond_init(&(*sem)->gtzero, NULL) != 0) {
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348 pthread_mutex_destroy(&(*sem)->lock);
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349 free(*sem);
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350 errno = ENOSPC;
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351 retval = -1;
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352 goto RETURN;
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353 }
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354
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355 (*sem)->count = (u_int32_t)value;
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356 (*sem)->nwaiters = 0;
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357 (*sem)->magic = SEM_MAGIC;
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358
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359 retval = 0;
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360 RETURN:
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361 return retval;
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362 }
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363
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364 int
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365 sem_destroy(sem_t *sem)
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366 {
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367 int retval;
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368
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369 _SEM_CHECK_VALIDITY(sem);
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370
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371 /* Make sure there are no waiters. */
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372 pthread_mutex_lock(&(*sem)->lock);
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373 if ((*sem)->nwaiters > 0) {
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374 pthread_mutex_unlock(&(*sem)->lock);
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375 errno = EBUSY;
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376 retval = -1;
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377 goto RETURN;
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378 }
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379 pthread_mutex_unlock(&(*sem)->lock);
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380
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381 pthread_mutex_destroy(&(*sem)->lock);
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382 pthread_cond_destroy(&(*sem)->gtzero);
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383 (*sem)->magic = 0;
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384
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385 free(*sem);
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386
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387 retval = 0;
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388 RETURN:
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389 return retval;
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|
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390 }
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391
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392 sem_t *
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393 sem_open(const char *name, int oflag, ...)
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394 {
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395 errno = ENOSYS;
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396 return SEM_FAILED;
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397 }
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398
|
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399 int
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400 sem_close(sem_t *sem)
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401 {
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402 errno = ENOSYS;
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403 return -1;
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404 }
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405
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406 int
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407 sem_unlink(const char *name)
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|
|
408 {
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|
|
409 errno = ENOSYS;
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|
|
410 return -1;
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|
411 }
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|
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412
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413 int
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|
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414 sem_wait(sem_t *sem)
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|
|
415 {
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|
|
416 int retval;
|
|
|
417
|
|
|
418 pthread_testcancel();
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419
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|
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420 _SEM_CHECK_VALIDITY(sem);
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|
|
421
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|
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422 pthread_mutex_lock(&(*sem)->lock);
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|
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423
|
|
|
424 while ((*sem)->count == 0) {
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|
|
425 (*sem)->nwaiters++;
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|
426 pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
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|
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427 (*sem)->nwaiters--;
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|
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428 }
|
|
|
429 (*sem)->count--;
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|
|
430
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|
|
431 pthread_mutex_unlock(&(*sem)->lock);
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|
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432
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|
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433 retval = 0;
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|
|
434 RETURN:
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|
|
435
|
|
|
436 pthread_testcancel();
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437 return retval;
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438 }
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439
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440 int
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441 sem_trywait(sem_t *sem)
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442 {
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443 int retval;
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444
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445 _SEM_CHECK_VALIDITY(sem);
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446
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447 pthread_mutex_lock(&(*sem)->lock);
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448
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449 if ((*sem)->count > 0) {
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450 (*sem)->count--;
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451 retval = 0;
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452 } else {
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453 errno = EAGAIN;
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454 retval = -1;
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455 }
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456
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457 pthread_mutex_unlock(&(*sem)->lock);
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458
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459 RETURN:
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460 return retval;
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461 }
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462
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463 int
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464 sem_post(sem_t *sem)
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465 {
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466 int retval;
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467
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468 _SEM_CHECK_VALIDITY(sem);
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469
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470 pthread_mutex_lock(&(*sem)->lock);
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471
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472 (*sem)->count++;
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473 if ((*sem)->nwaiters > 0) {
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474 /*
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475 * We must use pthread_cond_broadcast() rather than
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476 * pthread_cond_signal() in order to assure that the highest
|
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477 * priority thread is run by the scheduler, since
|
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478 * pthread_cond_signal() signals waiting threads in FIFO order.
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479 */
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|
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480 pthread_cond_broadcast(&(*sem)->gtzero);
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|
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481 }
|
|
|
482
|
|
|
483 pthread_mutex_unlock(&(*sem)->lock);
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|
|
484
|
|
|
485 retval = 0;
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486 RETURN:
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|
487 return retval;
|
|
|
488 }
|
|
|
489
|
|
|
490 int
|
|
|
491 sem_getvalue(sem_t *sem, int *sval)
|
|
|
492 {
|
|
|
493 int retval;
|
|
|
494
|
|
|
495 _SEM_CHECK_VALIDITY(sem);
|
|
|
496
|
|
|
497 pthread_mutex_lock(&(*sem)->lock);
|
|
|
498 *sval = (int)(*sem)->count;
|
|
|
499 pthread_mutex_unlock(&(*sem)->lock);
|
|
|
500
|
|
|
501 retval = 0;
|
|
|
502 RETURN:
|
|
|
503 return retval;
|
|
|
504 }
|
|
|
505
|
|
|
506 /* END of inlined uthread_sem.c */
|
|
|
507 #endif /* SDL_USE_PTHREADS */
|
