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root/cebix/SheepShaver/src/Unix/Linux/sheepthreads.c

Comparing SheepShaver/src/Unix/Linux/sheepthreads.c (file contents):
Revision 1.4 by gbeauche, 2004-01-04T16:27:50Z vs.
Revision 1.7 by gbeauche, 2005-06-25T11:00:30Z

#	Line 2 | Line 2
2		*  sheepthreads.c - Minimal pthreads implementation (libpthreads doesn't
3		*                   like nonstandard stacks)
4		*
5	<	*  SheepShaver (C) 1997-2002 Christian Bauer and Marc Hellwig
5	>	*  SheepShaver (C) 1997-2005 Christian Bauer and Marc Hellwig
6		*
7		*  This program is free software; you can redistribute it and/or modify
8		*  it under the terms of the GNU General Public License as published by
#	Line 33 | Line 33
33		#include <errno.h>
34		#include <unistd.h>
35		#include <signal.h>
36	–	#include <sched.h>
36		#include <pthread.h>
37		#include <semaphore.h>
38
#	Line 175 | Line 174 | void pthread_testcancel(void)
174		*  Spinlocks
175		*/
176
177	<	static int try_acquire_spinlock(int *lock)
177	>	/* For multiprocessor systems, we want to ensure all memory accesses
178	>	are completed before we reset a lock.  On other systems, we still
179	>	need to make sure that the compiler has flushed everything to memory.  */
180	>	#define MEMORY_BARRIER() __asm__ __volatile__ ("sync" : : : "memory")
181	>
182	>	static void fastlock_init(struct _pthread_fastlock *lock)
183		{
184	<	return test_and_set(lock, 1) == 0;
184	>	lock->status = 0;
185	>	lock->spinlock = 0;
186		}
187
188	<	static void acquire_spinlock(volatile int *lock)
188	>	static int fastlock_try_acquire(struct _pthread_fastlock *lock)
189		{
190	<	do {
191	<	while (*lock) ;
192	<	} while (test_and_set((int *)lock, 1) != 0);
190	>	int res = EBUSY;
191	>	if (test_and_set(&lock->spinlock, 1) == 0) {
192	>	if (lock->status == 0) {
193	>	lock->status = 1;
194	>	MEMORY_BARRIER();
195	>	res = 0;
196	>	}
197	>	lock->spinlock = 0;
198	>	}
199	>	return res;
200	>	}
201	>
202	>	static void fastlock_acquire(struct _pthread_fastlock *lock)
203	>	{
204	>	MEMORY_BARRIER();
205	>	while (test_and_set(&lock->spinlock, 1))
206	>	usleep(0);
207		}
208
209	<	static void release_spinlock(int *lock)
209	>	static void fastlock_release(struct _pthread_fastlock *lock)
210		{
211	<	*lock = 0;
211	>	MEMORY_BARRIER();
212	>	lock->spinlock = 0;
213	>	__asm__ __volatile__ ("" : "=m" (lock->spinlock) : "m" (lock->spinlock));
214		}
215
216
#	Line 199 | Line 220 | static void release_spinlock(int *lock)
220
221		int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *mutex_attr)
222		{
223	<	// pthread_init_lock
203	<	mutex->__m_lock.__status = 0;
204	<	mutex->__m_lock.__spinlock = 0;
205	<
223	>	fastlock_init(&mutex->__m_lock);
224		mutex->__m_kind = mutex_attr ? mutex_attr->__mutexkind : PTHREAD_MUTEX_TIMED_NP;
225		mutex->__m_count = 0;
226		mutex->__m_owner = NULL;
#	Line 233 | Line 251 | int pthread_mutex_lock(pthread_mutex_t *
251		{
252		switch (mutex->__m_kind) {
253		case PTHREAD_MUTEX_TIMED_NP:
254	<	acquire_spinlock(&mutex->__m_lock.__spinlock);
254	>	fastlock_acquire(&mutex->__m_lock);
255		return 0;
256		default:
257		return EINVAL;
#	Line 249 | Line 267 | int pthread_mutex_trylock(pthread_mutex_
267		{
268		switch (mutex->__m_kind) {
269		case PTHREAD_MUTEX_TIMED_NP:
270	<	if (!try_acquire_spinlock(&mutex->__m_lock.__spinlock))
253	<	return EBUSY;
254	<	return 0;
270	>	return fastlock_try_acquire(&mutex->__m_lock);
271		default:
272		return EINVAL;
273		}
#	Line 266 | Line 282 | int pthread_mutex_unlock(pthread_mutex_t
282		{
283		switch (mutex->__m_kind) {
284		case PTHREAD_MUTEX_TIMED_NP:
285	<	release_spinlock(&mutex->__m_lock.__spinlock);
285	>	fastlock_release(&mutex->__m_lock);
286		return 0;
287		default:
288		return EINVAL;
#	Line 301 | Line 317 | int pthread_mutexattr_destroy(pthread_mu
317
318		int sem_init(sem_t *sem, int pshared, unsigned int value)
319		{
320	<	sem->sem_lock.status = 0;
321	<	sem->sem_lock.spinlock = 0;
320	>	if (sem == NULL || value > SEM_VALUE_MAX) {
321	>	errno = EINVAL;
322	>	return -1;
323	>	}
324	>	if (pshared) {
325	>	errno = ENOSYS;
326	>	return -1;
327	>	}
328	>	fastlock_init(&sem->sem_lock);
329		sem->sem_value = value;
330		sem->sem_waiting = NULL;
331		return 0;
#	Line 315 | Line 338 | int sem_init(sem_t *sem, int pshared, un
338
339		int sem_destroy(sem_t *sem)
340		{
341	+	if (sem == NULL) {
342	+	errno = EINVAL;
343	+	return -1;
344	+	}
345	+	if (sem->sem_waiting) {
346	+	errno = EBUSY;
347	+	return -1;
348	+	}
349	+	sem->sem_value = 0;
350	+	sem->sem_waiting = NULL;
351		return 0;
352		}
353
#	Line 323 | Line 356 | int sem_destroy(sem_t *sem)
356		*  Wait on semaphore
357		*/
358
326	–	void null_handler(int sig)
327	–	{
328	–	}
329	–
359		int sem_wait(sem_t *sem)
360		{
361	<	acquire_spinlock(&sem->sem_lock.spinlock);
362	<	if (sem->sem_value > 0)
363	<	atomic_add((int *)&sem->sem_value, -1);
364	<	else {
365	<	sigset_t mask;
366	<	if (!sem->sem_lock.status) {
367	<	struct sigaction sa;
368	<	sem->sem_lock.status = SIGUSR2;
369	<	sa.sa_handler = null_handler;
370	<	sa.sa_flags = SA_RESTART;
371	<	sigemptyset(&sa.sa_mask);
372	<	sigaction(sem->sem_lock.status, &sa, NULL);
373	<	}
374	<	sem->sem_waiting = (struct _pthread_descr_struct *)getpid();
375	<	sigemptyset(&mask);
376	<	sigsuspend(&mask);
377	<	sem->sem_waiting = NULL;
361	>	int cnt = 0;
362	>	struct timespec tm;
363	>
364	>	if (sem == NULL) {
365	>	errno = EINVAL;
366	>	return -1;
367	>	}
368	>	fastlock_acquire(&sem->sem_lock);
369	>	if (sem->sem_value > 0) {
370	>	sem->sem_value--;
371	>	fastlock_release(&sem->sem_lock);
372	>	return 0;
373	>	}
374	>	sem->sem_waiting = (struct _pthread_descr_struct *)((long)sem->sem_waiting + 1);
375	>	while (sem->sem_value == 0) {
376	>	fastlock_release(&sem->sem_lock);
377	>	usleep(0);
378	>	fastlock_acquire(&sem->sem_lock);
379		}
380	<	release_spinlock(&sem->sem_lock.spinlock);
380	>	sem->sem_value--;
381	>	fastlock_release(&sem->sem_lock);
382		return 0;
383		}
384
#	Line 358 | Line 389 | int sem_wait(sem_t *sem)
389
390		int sem_post(sem_t *sem)
391		{
392	<	acquire_spinlock(&sem->sem_lock.spinlock);
393	<	if (sem->sem_waiting == NULL)
394	<	atomic_add((int *)&sem->sem_value, 1);
395	<	else
396	<	kill((pid_t)sem->sem_waiting, sem->sem_lock.status);
397	<	release_spinlock(&sem->sem_lock.spinlock);
392	>	if (sem == NULL) {
393	>	errno = EINVAL;
394	>	return -1;
395	>	}
396	>	fastlock_acquire(&sem->sem_lock);
397	>	if (sem->sem_waiting)
398	>	sem->sem_waiting = (struct _pthread_descr_struct *)((long)sem->sem_waiting - 1);
399	>	else {
400	>	if (sem->sem_value >= SEM_VALUE_MAX) {
401	>	errno = ERANGE;
402	>	fastlock_release(&sem->sem_lock);
403	>	return -1;
404	>	}
405	>	}
406	>	sem->sem_value++;
407	>	fastlock_release(&sem->sem_lock);
408		return 0;
409		}
410

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