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/* $Id: thread.c 1153 2011-07-27 05:12:30Z michael $
* $URL: https://ssl.bulix.org/svn/lcd4linux/trunk/thread.c $
*
* thread handling (mutex, shmem, ...)
*
* Copyright (C) 2004 Michael Reinelt <michael@reinelt.co.at>
* Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net>
*
* parts of this code are based on the old XWindow driver which is
* Copyright (C) 2000 Herbert Rosmanith <herp@wildsau.idv.uni-linz.ac.at>
*
* This file is part of LCD4Linux.
*
* LCD4Linux is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* LCD4Linux is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
/*
* exported functions:
*
* int mutex_create (void);
* creates a mutex and treturns its ID
*
* void mutex_lock (int semid);
* try to lock a mutex
*
* void mutex_unlock (int semid);
* unlock a mutex
*
* void mutex_destroy (int semid);
* release a mutex
*
*
* int shm_create (void **buffer, int size);
* create shared memory segment
*
* void shm_destroy (int shmid, void *buffer) ;
* release shared memory segment
*
* int thread_create (char *name, void (*thread)(void *data), void *data);
* create a new thread
*
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include "debug.h"
#include "thread.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif
int thread_argc;
char **thread_argv;
/* glibc 2.1 requires defining semun ourselves */
#ifdef _SEM_SEMUN_UNDEFINED
union semun {
int val;
struct semid_ds *buf;
unsigned short int *array;
struct seminfo *__buf;
};
#endif
int mutex_create(void)
{
int semid;
union semun semun;
semid = semget(IPC_PRIVATE, 1, 0);
if (semid == -1) {
error("fatal error: semget() failed: %s", strerror(errno));
return -1;
}
semun.val = 1;
semctl(semid, 0, SETVAL, semun);
return semid;
}
void mutex_lock(const int semid)
{
struct sembuf sembuf;
sembuf.sem_num = 0;
sembuf.sem_op = -1;
sembuf.sem_flg = 0;
semop(semid, &sembuf, 1);
}
void mutex_unlock(const int semid)
{
struct sembuf sembuf;
sembuf.sem_num = 0;
sembuf.sem_op = 1;
sembuf.sem_flg = 0;
semop(semid, &sembuf, 1);
}
void mutex_destroy(const int semid)
{
union semun arg;
semctl(semid, 0, IPC_RMID, arg);
}
int shm_create(void **buffer, const int size)
{
int shmid;
shmid = shmget(IPC_PRIVATE, size, SHM_R | SHM_W);
if (shmid == -1) {
error("fatal error: shmget() failed: %s", strerror(errno));
return -1;
}
*buffer = shmat(shmid, NULL, 0);
if (*buffer == NULL) {
error("fatal error: shmat() failed: %s", strerror(errno));
return -1;
}
return shmid;
}
void shm_destroy(const int shmid, const void *buffer)
{
shmdt(buffer);
shmctl(shmid, IPC_RMID, NULL);
}
int thread_create(const char *name, void (*thread) (void *data), void *data)
{
pid_t pid;
switch (pid = fork()) {
case -1:
error("fatal error: fork(%s) failed: %s", name, strerror(errno));
return -1;
case 0:
info("thread %s starting...", name);
if (thread_argc > 0) {
strncpy(thread_argv[0], name, strlen(thread_argv[0]));
}
thread(data);
info("thread %s ended.", name);
exit(0);
default:
info("forked process %d for thread %s", pid, name);
}
return pid;
}
int thread_destroy(const int pid)
{
return kill(pid, SIGKILL);
}
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