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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 
     22 /*
     23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     28 
     29 #include "lint.h"
     30 #include "thr_uberdata.h"
     31 #include <pthread.h>
     32 
     33 /*
     34  * Implementation-private attribute structure (for extensibility).
     35  */
     36 typedef struct {
     37 	int	pshared;
     38 } barrierattr_t;
     39 
     40 int
     41 pthread_barrierattr_init(pthread_barrierattr_t *attr)
     42 {
     43 	barrierattr_t *ap;
     44 
     45 	if ((ap = lmalloc(sizeof (barrierattr_t))) == NULL)
     46 		return (ENOMEM);
     47 	ap->pshared = PTHREAD_PROCESS_PRIVATE;
     48 	attr->__pthread_barrierattrp = ap;
     49 	return (0);
     50 }
     51 
     52 int
     53 pthread_barrierattr_destroy(pthread_barrierattr_t *attr)
     54 {
     55 	if (attr == NULL || attr->__pthread_barrierattrp == NULL)
     56 		return (EINVAL);
     57 	lfree(attr->__pthread_barrierattrp, sizeof (barrierattr_t));
     58 	attr->__pthread_barrierattrp = NULL;
     59 	return (0);
     60 }
     61 
     62 int
     63 pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int pshared)
     64 {
     65 	barrierattr_t *ap;
     66 
     67 	if (attr == NULL || (ap = attr->__pthread_barrierattrp) == NULL ||
     68 	    (pshared != PTHREAD_PROCESS_PRIVATE &&
     69 	    pshared != PTHREAD_PROCESS_SHARED))
     70 		return (EINVAL);
     71 	ap->pshared = pshared;
     72 	return (0);
     73 }
     74 
     75 int
     76 pthread_barrierattr_getpshared(const pthread_barrierattr_t *attr, int *pshared)
     77 {
     78 	barrierattr_t *ap;
     79 
     80 	if (attr == NULL || (ap = attr->__pthread_barrierattrp) == NULL ||
     81 	    pshared == NULL)
     82 		return (EINVAL);
     83 	*pshared = ap->pshared;
     84 	return (0);
     85 }
     86 
     87 int
     88 pthread_barrier_init(pthread_barrier_t *barrier,
     89     const pthread_barrierattr_t *attr, uint_t count)
     90 {
     91 	mutex_t *mp = (mutex_t *)&barrier->__pthread_barrier_lock;
     92 	cond_t *cvp = (cond_t *)&barrier->__pthread_barrier_cond;
     93 	barrierattr_t *ap;
     94 	int type;
     95 
     96 	if (attr == NULL)
     97 		type = DEFAULT_TYPE;
     98 	else if ((ap = attr->__pthread_barrierattrp) != NULL)
     99 		type = ap->pshared;
    100 	else
    101 		type = -1;
    102 
    103 	if (count == 0 ||
    104 	    (type != PTHREAD_PROCESS_PRIVATE && type != PTHREAD_PROCESS_SHARED))
    105 		return (EINVAL);
    106 
    107 	barrier->__pthread_barrier_count = count;
    108 	barrier->__pthread_barrier_current = count;
    109 	barrier->__pthread_barrier_cycle = 0;
    110 	barrier->__pthread_barrier_reserved = 0;
    111 	(void) mutex_init(mp, type, NULL);
    112 	(void) cond_init(cvp, type, NULL);
    113 
    114 	/*
    115 	 * This should be at the beginning of the function,
    116 	 * but for the sake of old broken applications that
    117 	 * do not have proper alignment for their barriers
    118 	 * (and don't check the return code from pthread_barrier_init),
    119 	 * we put it here, after initializing the barrier regardless.
    120 	 */
    121 	if (((uintptr_t)barrier & (_LONG_LONG_ALIGNMENT - 1)) &&
    122 	    curthread->ul_misaligned == 0)
    123 		return (EINVAL);
    124 
    125 	return (0);
    126 }
    127 
    128 int
    129 pthread_barrier_destroy(pthread_barrier_t *barrier)
    130 {
    131 	mutex_t *mp = (mutex_t *)&barrier->__pthread_barrier_lock;
    132 	cond_t *cvp = (cond_t *)&barrier->__pthread_barrier_cond;
    133 
    134 	(void) mutex_destroy(mp);
    135 	(void) cond_destroy(cvp);
    136 	(void) memset(barrier, -1, sizeof (*barrier));
    137 	return (0);
    138 }
    139 
    140 /*
    141  * pthread_barrier_wait() is not a cancellation point;
    142  */
    143 int
    144 pthread_barrier_wait(pthread_barrier_t *barrier)
    145 {
    146 	mutex_t *mp = (mutex_t *)&barrier->__pthread_barrier_lock;
    147 	cond_t *cvp = (cond_t *)&barrier->__pthread_barrier_cond;
    148 	uint64_t cycle;
    149 	int cancel_state;
    150 
    151 	(void) mutex_lock(mp);
    152 
    153 	if (--barrier->__pthread_barrier_current == 0) {
    154 		barrier->__pthread_barrier_cycle++;
    155 		barrier->__pthread_barrier_current =
    156 		    barrier->__pthread_barrier_count;
    157 		(void) mutex_unlock(mp);
    158 		(void) cond_broadcast(cvp);
    159 		return (PTHREAD_BARRIER_SERIAL_THREAD);
    160 	}
    161 
    162 	(void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
    163 	cycle = barrier->__pthread_barrier_cycle;
    164 	do {
    165 		(void) cond_wait(cvp, mp);
    166 	} while (cycle == barrier->__pthread_barrier_cycle);
    167 	(void) pthread_setcancelstate(cancel_state, NULL);
    168 
    169 	(void) mutex_unlock(mp);
    170 	return (0);
    171 }
    172