[dragonfly.git] / lib / libthread_xu / thread / thr_sem.c

/*
 * Copyright (C) 2005 David Xu <davidxu@freebsd.org>.
 * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice(s), this list of conditions and the following disclaimer as
 *    the first lines of this file unmodified other than the possible
 *    addition of one or more copyright notices.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice(s), this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $DragonFly: src/lib/libthread_xu/thread/thr_sem.c,v 1.6 2007/06/26 23:30:05 josepht Exp $
 */

#include "namespace.h"
#include <machine/tls.h>
#include <sys/semaphore.h>
#include <sys/mman.h>

#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdlib.h>
#include <time.h>
#include "un-namespace.h"
#include "thr_private.h"

/*
 * Semaphore definitions.
 */
struct sem {
	u_int32_t		magic;
	volatile umtx_t		count;
	int			semid;
	int			unused;	/* pad */
};

#define	SEM_MAGIC	((u_int32_t) 0x09fa4012)

#define SEMID_LWP	0
#define SEMID_FORK	1

static inline int
sem_check_validity(sem_t *sem)
{

	if ((sem != NULL) && ((*sem)->magic == SEM_MAGIC)) {
		return (0);
	} else {
		errno = EINVAL;
		return (-1);
	}
}

static sem_t
sem_alloc(unsigned int value, int pshared)
{
	sem_t sem;
	int semid;

	if (value > SEM_VALUE_MAX) {
		errno = EINVAL;
		return (NULL);
	}
	if (pshared) {
		static __thread sem_t sem_base;
		static __thread int sem_count;

		if (sem_base == NULL) {
			sem_base = mmap(NULL, getpagesize(),
					PROT_READ | PROT_WRITE,
					MAP_ANON | MAP_SHARED,
					-1, 0);
			sem_count = getpagesize() / sizeof(*sem);
		}
		sem = sem_base++;
		if (--sem_count == 0)
			sem_base = NULL;
		semid = SEMID_FORK;
	} else {
		sem = malloc(sizeof(struct sem));
		semid = SEMID_LWP;
	}
	if (sem == NULL) {
		errno = ENOSPC;
		return (NULL);
	}
	sem->magic = SEM_MAGIC;
	sem->count = (u_int32_t)value;
	sem->semid = semid;
	return (sem);
}

int
_sem_init(sem_t *sem, int pshared, unsigned int value)
{
	(*sem) = sem_alloc(value, pshared);
	if ((*sem) == NULL)
		return (-1);
	return (0);
}

int
_sem_destroy(sem_t *sem)
{
	if (sem_check_validity(sem) != 0)
		return (-1);

	(*sem)->magic = 0;

	switch ((*sem)->semid) {
	case SEMID_LWP:
		free(*sem);
		break;
	case SEMID_FORK:
		/* memory is left intact */
		break;
	}
	return (0);
}

int
_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
{
	if (sem_check_validity(sem) != 0)
		return (-1);

	*sval = (*sem)->count;
	return (0);
}

int
_sem_trywait(sem_t *sem)
{
	int val;

	if (sem_check_validity(sem) != 0)
		return (-1);

	while ((val = (*sem)->count) > 0) {
		if (atomic_cmpset_int(&(*sem)->count, val, val - 1))
			return (0);
	}
	errno = EAGAIN;
	return (-1);
}

int
_sem_wait(sem_t *sem)
{
	struct pthread *curthread;
	int val, oldcancel, retval;

	if (sem_check_validity(sem) != 0)
		return (-1);

	curthread = tls_get_curthread();
	_pthread_testcancel();
	do {
		while ((val = (*sem)->count) > 0) {
			if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
				return (0);
		}
		oldcancel = _thr_cancel_enter(curthread);
		retval = _thr_umtx_wait(&(*sem)->count, 0, NULL, 0);
		_thr_cancel_leave(curthread, oldcancel);
	} while (retval == 0);
	errno = retval;
	return (-1);
}

#if 0
int
_sem_timedwait(sem_t * __restrict sem, struct timespec * __restrict abstime)
{
	struct timespec ts, ts2;
	struct pthread *curthread;
	int val, oldcancel, retval;

	if (sem_check_validity(sem) != 0)
		return (-1);

	curthread = tls_get_curthread();

	/*
	 * The timeout argument is only supposed to
	 * be checked if the thread would have blocked.
	 */
	_pthread_testcancel();
	do {
		while ((val = (*sem)->count) > 0) {
			if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
				return (0);
		}
		if (abstime == NULL) {
			errno = EINVAL;
			return (-1);
		}
		clock_gettime(CLOCK_REALTIME, &ts);
		TIMESPEC_SUB(&ts2, abstime, &ts);
		oldcancel = _thr_cancel_enter(curthread);
		retval = _thr_umtx_wait(&(*sem)->count, 0, &ts2,
					CLOCK_REALTIME);
		_thr_cancel_leave(curthread, oldcancel);
	} while (retval == 0);
	errno = retval;
	return (-1);
}
#endif

int
_sem_post(sem_t *sem)
{
	int val;
	
	if (sem_check_validity(sem) != 0)
		return (-1);

	/*
	 * sem_post() is required to be safe to call from within
	 * signal handlers, these code should work as that.
	 */
	do {
		val = (*sem)->count;
	} while (!atomic_cmpset_acq_int(&(*sem)->count, val, val + 1));
	_thr_umtx_wake(&(*sem)->count, val + 1);
	return (0);
}

sem_t *
_sem_open(const char *name, int oflag, ...)
{
	errno = ENOSYS;
	return (SEM_FAILED);
}

int
_sem_close(sem_t *sem)
{
	errno = ENOSYS;
	return (-1);
}

int
_sem_unlink(const char *name)
{
	errno = ENOSYS;
	return (-1);
}

__strong_reference(_sem_destroy, sem_destroy);
__strong_reference(_sem_getvalue, sem_getvalue);
__strong_reference(_sem_init, sem_init);
__strong_reference(_sem_trywait, sem_trywait);
__strong_reference(_sem_wait, sem_wait);
#if 0
__strong_reference(_sem_timedwait, sem_timedwait);
#endif
__strong_reference(_sem_post, sem_post);
__strong_reference(_sem_open, sem_open);
__strong_reference(_sem_close, sem_close);
__strong_reference(_sem_unlink, sem_unlink);
Commit	Line	Data
71b3fa15 DX	1	/*
	2	* Copyright (C) 2005 David Xu <davidxu@freebsd.org>.
	3	* Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
	4	* All rights reserved.
	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice(s), this list of conditions and the following disclaimer as
	11	* the first lines of this file unmodified other than the possible
	12	* addition of one or more copyright notices.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice(s), this list of conditions and the following disclaimer in
	15	* the documentation and/or other materials provided with the
	16	* distribution.
	17	*
	18	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
	19	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	20	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	21	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
	22	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	23	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	24	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	25	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	26	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
	27	* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
	28	* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	29	*
c4dd4100	30	* $DragonFly: src/lib/libthread_xu/thread/thr_sem.c,v 1.6 2007/06/26 23:30:05 josepht Exp $
71b3fa15 DX	31	*/
71b3fa15 DX	32
fc71f871	33	#include "namespace.h"
9e2ee207	34	#include <machine/tls.h>
c4dd4100	35	#include <sys/semaphore.h>
328161bd	36	#include <sys/mman.h>
9e2ee207	37
71b3fa15 DX	38	#include <errno.h>
	39	#include <fcntl.h>
	40	#include <pthread.h>
71b3fa15 DX	41	#include <stdlib.h>
71b3fa15 DX	42	#include <time.h>
fc71f871	43	#include "un-namespace.h"
71b3fa15 DX	44	#include "thr_private.h"
71b3fa15 DX	45
71b3fa15 DX	46	/*
	47	* Semaphore definitions.
	48	*/
	49	struct sem {
71b3fa15 DX	50	u_int32_t magic;
71b3fa15 DX	51	volatile umtx_t count;
328161bd MD	52	int semid;
328161bd MD	53	int unused; /* pad */
71b3fa15 DX	54	};
71b3fa15 DX	55
328161bd MD	56	#define SEM_MAGIC ((u_int32_t) 0x09fa4012)
	57
	58	#define SEMID_LWP 0
	59	#define SEMID_FORK 1
	60
71b3fa15 DX	61	static inline int
	62	sem_check_validity(sem_t *sem)
	63	{
	64
328161bd	65	if ((sem != NULL) && ((*sem)->magic == SEM_MAGIC)) {
71b3fa15	66	return (0);
328161bd	67	} else {
71b3fa15 DX	68	errno = EINVAL;
	69	return (-1);
	70	}
	71	}
	72
	73	static sem_t
328161bd	74	sem_alloc(unsigned int value, int pshared)
71b3fa15 DX	75	{
71b3fa15 DX	76	sem_t sem;
328161bd	77	int semid;
71b3fa15 DX	78
	79	if (value > SEM_VALUE_MAX) {
	80	errno = EINVAL;
	81	return (NULL);
	82	}
328161bd MD	83	if (pshared) {
	84	static __thread sem_t sem_base;
	85	static __thread int sem_count;
	86
	87	if (sem_base == NULL) {
	88	sem_base = mmap(NULL, getpagesize(),
	89	PROT_READ \| PROT_WRITE,
	90	MAP_ANON \| MAP_SHARED,
	91	-1, 0);
	92	sem_count = getpagesize() / sizeof(*sem);
	93	}
	94	sem = sem_base++;
	95	if (--sem_count == 0)
	96	sem_base = NULL;
	97	semid = SEMID_FORK;
	98	} else {
	99	sem = malloc(sizeof(struct sem));
	100	semid = SEMID_LWP;
	101	}
71b3fa15 DX	102	if (sem == NULL) {
	103	errno = ENOSPC;
	104	return (NULL);
	105	}
	106	sem->magic = SEM_MAGIC;
	107	sem->count = (u_int32_t)value;
	108	sem->semid = semid;
	109	return (sem);
	110	}
	111
	112	int
	113	_sem_init(sem_t *sem, int pshared, unsigned int value)
	114	{
328161bd	115	(*sem) = sem_alloc(value, pshared);
71b3fa15 DX	116	if ((*sem) == NULL)
	117	return (-1);
	118	return (0);
	119	}
	120
	121	int
	122	_sem_destroy(sem_t *sem)
	123	{
	124	if (sem_check_validity(sem) != 0)
	125	return (-1);
	126
328161bd MD	127	(*sem)->magic = 0;
	128
	129	switch ((*sem)->semid) {
	130	case SEMID_LWP:
	131	free(*sem);
	132	break;
	133	case SEMID_FORK:
	134	/* memory is left intact */
	135	break;
	136	}
71b3fa15 DX	137	return (0);
	138	}
	139
71b3fa15 DX	140	int
	141	_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
	142	{
	143	if (sem_check_validity(sem) != 0)
	144	return (-1);
	145
	146	sval = (sem)->count;
	147	return (0);
	148	}
	149
	150	int
	151	_sem_trywait(sem_t *sem)
	152	{
	153	int val;
	154
	155	if (sem_check_validity(sem) != 0)
	156	return (-1);
	157
	158	while ((val = (*sem)->count) > 0) {
	159	if (atomic_cmpset_int(&(*sem)->count, val, val - 1))
	160	return (0);
	161	}
	162	errno = EAGAIN;
	163	return (-1);
	164	}
	165
	166	int
	167	_sem_wait(sem_t *sem)
	168	{
	169	struct pthread *curthread;
	170	int val, oldcancel, retval;
	171
	172	if (sem_check_validity(sem) != 0)
	173	return (-1);
	174
9e2ee207	175	curthread = tls_get_curthread();
71b3fa15 DX	176	_pthread_testcancel();
	177	do {
	178	while ((val = (*sem)->count) > 0) {
	179	if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
	180	return (0);
	181	}
	182	oldcancel = _thr_cancel_enter(curthread);
9219c44c	183	retval = _thr_umtx_wait(&(*sem)->count, 0, NULL, 0);
71b3fa15 DX	184	_thr_cancel_leave(curthread, oldcancel);
	185	} while (retval == 0);
	186	errno = retval;
	187	return (-1);
	188	}
	189
fc71f871	190	#if 0
71b3fa15 DX	191	int
	192	_sem_timedwait(sem_t * __restrict sem, struct timespec * __restrict abstime)
	193	{
	194	struct timespec ts, ts2;
	195	struct pthread *curthread;
	196	int val, oldcancel, retval;
	197
	198	if (sem_check_validity(sem) != 0)
	199	return (-1);
	200
9e2ee207	201	curthread = tls_get_curthread();
71b3fa15 DX	202
	203	/*
	204	* The timeout argument is only supposed to
	205	* be checked if the thread would have blocked.
	206	*/
	207	_pthread_testcancel();
	208	do {
	209	while ((val = (*sem)->count) > 0) {
	210	if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
	211	return (0);
	212	}
	213	if (abstime == NULL) {
	214	errno = EINVAL;
	215	return (-1);
	216	}
	217	clock_gettime(CLOCK_REALTIME, &ts);
	218	TIMESPEC_SUB(&ts2, abstime, &ts);
	219	oldcancel = _thr_cancel_enter(curthread);
9219c44c DX	220	retval = _thr_umtx_wait(&(*sem)->count, 0, &ts2,
9219c44c DX	221	CLOCK_REALTIME);
71b3fa15 DX	222	_thr_cancel_leave(curthread, oldcancel);
	223	} while (retval == 0);
	224	errno = retval;
	225	return (-1);
	226	}
fc71f871	227	#endif
71b3fa15 DX	228
	229	int
	230	_sem_post(sem_t *sem)
	231	{
	232	int val;
	233
	234	if (sem_check_validity(sem) != 0)
	235	return (-1);
	236
	237	/*
	238	* sem_post() is required to be safe to call from within
	239	* signal handlers, these code should work as that.
	240	*/
	241	do {
	242	val = (*sem)->count;
	243	} while (!atomic_cmpset_acq_int(&(*sem)->count, val, val + 1));
	244	_thr_umtx_wake(&(*sem)->count, val + 1);
	245	return (0);
	246	}
5a1048c8	247
86926582 VS	248	sem_t *
	249	_sem_open(const char *name, int oflag, ...)
	250	{
	251	errno = ENOSYS;
	252	return (SEM_FAILED);
	253	}
	254
	255	int
	256	_sem_close(sem_t *sem)
	257	{
	258	errno = ENOSYS;
	259	return (-1);
	260	}
	261
	262	int
	263	_sem_unlink(const char *name)
	264	{
	265	errno = ENOSYS;
	266	return (-1);
	267	}
	268
5a1048c8 DX	269	__strong_reference(_sem_destroy, sem_destroy);
	270	__strong_reference(_sem_getvalue, sem_getvalue);
	271	__strong_reference(_sem_init, sem_init);
5a1048c8 DX	272	__strong_reference(_sem_trywait, sem_trywait);
5a1048c8 DX	273	__strong_reference(_sem_wait, sem_wait);
fc71f871	274	#if 0
5a1048c8	275	__strong_reference(_sem_timedwait, sem_timedwait);
fc71f871	276	#endif
5a1048c8	277	__strong_reference(_sem_post, sem_post);
86926582 VS	278	__strong_reference(_sem_open, sem_open);
	279	__strong_reference(_sem_close, sem_close);
	280	__strong_reference(_sem_unlink, sem_unlink);
5a1048c8	281