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/* |
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* posix_sem.cpp - POSIX.4 semaphores "emulation" |
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* Copyright (C) 1999 Orlando Bassotto |
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* |
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* Basilisk II (C) 1997-1999 Christian Bauer |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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|
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/* |
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* OK, I had really big problems with SysV semaphores :/ |
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* I rewrote those one giving a look to the source of linuxthreads |
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* with mutex. Seems to be working correctly now. |
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*/ |
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|
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#include <stdio.h> |
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#include <sys/types.h> |
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#include <errno.h> |
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#include <pthread.h> |
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#include "semaphore.h" |
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|
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extern "C" { |
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|
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int sem_init(sem_t* sem, int pshared, unsigned int value) |
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{ |
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if(sem==NULL||value>SEM_VALUE_MAX) { |
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errno = EINVAL; |
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return -1; |
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} |
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if(pshared) { |
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errno = ENOSYS; |
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return -1; |
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} |
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pthread_mutex_init(&sem->sem_lock, NULL); |
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sem->sem_value = value; |
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sem->sem_waiting = 0; |
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return 0; |
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} |
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|
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|
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int sem_destroy(sem_t* sem) |
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{ |
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if(sem==NULL) { |
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errno = EINVAL; |
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return -1; |
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} |
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if(sem->sem_waiting) { |
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errno = EBUSY; |
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return -1; |
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} |
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pthread_mutex_destroy(&sem->sem_lock); |
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sem->sem_waiting = 0; |
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sem->sem_lock = NULL; |
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sem->sem_value = 0; |
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return 0; |
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} |
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|
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sem_t sem_open(const char* name, int oflag, ...) |
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{ |
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errno = ENOSYS; |
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return *(sem_t*)NULL; |
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} |
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|
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int sem_close(sem_t* sem) |
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{ |
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errno = ENOSYS; |
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return -1; |
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} |
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|
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int sem_unlink(const char* name) |
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{ |
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errno = ENOSYS; |
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return -1; |
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} |
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|
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int sem_wait(sem_t* sem) |
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{ |
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struct timespec req = { 1, 0 }; |
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|
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if(sem==NULL) { |
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errno = EINVAL; |
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return -1; |
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} |
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pthread_mutex_lock(&sem->sem_lock); |
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sem->sem_waiting++; |
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if(sem->sem_value > 0) { |
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--sem->sem_value; |
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return 0; |
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} |
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while(!sem->sem_value) nanosleep(NULL, &req); |
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pthread_mutex_unlock(&sem->sem_lock); |
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return 0; |
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} |
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|
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int sem_trywait(sem_t* sem) |
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{ |
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errno = ENOSYS; |
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return -1; |
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} |
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|
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int sem_post(sem_t* sem) |
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{ |
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if(sem==NULL) { |
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errno = EINVAL; |
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return -1; |
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} |
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if(!sem->sem_waiting) { |
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if(sem->sem_value >= SEM_VALUE_MAX) { |
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errno = ERANGE; |
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pthread_mutex_unlock(&sem->sem_lock); |
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return -1; |
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} |
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++sem->sem_value; |
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pthread_mutex_unlock(&sem->sem_lock); |
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} |
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else { |
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sem->sem_waiting--; |
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++sem->sem_value; |
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// pthread_mutex_unlock(&sem->sem_lock); |
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} |
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return 0; |
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} |
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|
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int sem_getvalue(sem_t* sem, int* sval) |
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{ |
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errno = ENOSYS; |
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return -1; |
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} |
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|
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} |
