uclibc-ng/libpthread/pthread.c

/* vi: set sw=4 ts=4: */
/*
 * A simple clopne based pthread implementation
 *
 * Copyright (C) 2001 by Erik Andersen <andersee@debian.org>
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 *
 * This program 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <stdlib.h>
#include <sched.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <pthread.h>

#define STACKSIZE 8096

#define CSIGNAL         0x000000ff      /* signal mask to be sent at exit */
#define CLONE_VM        0x00000100      /* set if VM shared between processes */
#define CLONE_FS        0x00000200      /* set if fs info shared between proces ses */
#define CLONE_FILES     0x00000400      /* set if open files shared between pro cesses */
#define CLONE_SIGHAND   0x00000800      /* set if signal handlers shared */



/* Lame home-grown clone based threading */
int pthread_mutex_init (pthread_mutex_t *mutex, const pthread_mutexattr_t *mutex_attr)
{
    mutex->__m_lock.__spinlock = 1;
	return 0;
}

int pthread_mutex_lock (pthread_mutex_t *mutex)
{
	while (mutex->__m_lock.__spinlock == 0) {
	usleep(10000);
    }
    --(mutex->__m_lock.__spinlock);
	return 0;
}

int pthread_mutex_unlock (pthread_mutex_t *mutex)
{
    ++(mutex->__m_lock.__spinlock);
	return 0;
}

int pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
{
    ++(mutex->__m_lock.__spinlock);
    while (cond->__c_lock.__spinlock == 0) {
	usleep(10000);
    }
    --(cond->__c_lock.__spinlock);
	return 0;
}

int pthread_cond_signal(pthread_cond_t *cond)
{
    ++(cond->__c_lock.__spinlock);
	return 0;
}

int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr)
{
    cond->__c_lock.__spinlock = 1;
	return 0;
}

int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void* (*fn)(void *), void *data)
{
    long retval;
    void **newstack;
	int (*clonefunc)(void *) = (int (*)(void *))(fn);

    newstack = (void **) malloc(STACKSIZE);
    if (!newstack)
	return -1;
    newstack = (void **) (STACKSIZE + (char *) newstack);
    *--newstack = data;
    retval = clone(clonefunc, newstack, 
			CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD, data);  
    if (retval < 0) {
	errno = -retval;
	*thread = 0;
	retval = -1;
    } else {
	*thread = retval;
	retval = 0;
    }
    return retval;
}