usr/src/lib/libc/port/threads/pthr_barrier.c

   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 #include "lint.h"
  28 #include "thr_uberdata.h"
  29 #include <pthread.h>
  30
  31 /*
  32  * Implementation-private attribute structure (for extensibility).
  33  */
  34 typedef struct {
  35         int     pshared;
  36 } barrierattr_t;
  37
  38 int
  39 pthread_barrierattr_init(pthread_barrierattr_t *attr)
  40 {
  41         barrierattr_t *ap;
  42
  43         if ((ap = lmalloc(sizeof (barrierattr_t))) == NULL)
  44                 return (ENOMEM);
  45         ap->pshared = PTHREAD_PROCESS_PRIVATE;
  46         attr->__pthread_barrierattrp = ap;
  47         return (0);
  48 }
  49
  50 int
  51 pthread_barrierattr_destroy(pthread_barrierattr_t *attr)
  52 {
  53         if (attr == NULL || attr->__pthread_barrierattrp == NULL)
  54                 return (EINVAL);
  55         lfree(attr->__pthread_barrierattrp, sizeof (barrierattr_t));
  56         attr->__pthread_barrierattrp = NULL;
  57         return (0);
  58 }
  59
  60 int
  61 pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int pshared)
  62 {
  63         barrierattr_t *ap;
  64
  65         if (attr == NULL || (ap = attr->__pthread_barrierattrp) == NULL ||
  66             (pshared != PTHREAD_PROCESS_PRIVATE &&
  67             pshared != PTHREAD_PROCESS_SHARED))
  68                 return (EINVAL);
  69         ap->pshared = pshared;
  70         return (0);
  71 }
  72
  73 int
  74 pthread_barrierattr_getpshared(const pthread_barrierattr_t *attr, int *pshared)
  75 {
  76         barrierattr_t *ap;
  77
  78         if (attr == NULL || (ap = attr->__pthread_barrierattrp) == NULL ||
  79             pshared == NULL)
  80                 return (EINVAL);
  81         *pshared = ap->pshared;
  82         return (0);
  83 }
  84
  85 int
  86 pthread_barrier_init(pthread_barrier_t *barrier,
  87     const pthread_barrierattr_t *attr, uint_t count)
  88 {
  89         mutex_t *mp = (mutex_t *)&barrier->__pthread_barrier_lock;
  90         cond_t *cvp = (cond_t *)&barrier->__pthread_barrier_cond;
  91         barrierattr_t *ap;
  92         int type;
  93
  94         if (attr == NULL)
  95                 type = PTHREAD_PROCESS_PRIVATE;
  96         else if ((ap = attr->__pthread_barrierattrp) != NULL)
  97                 type = ap->pshared;
  98         else
  99                 type = -1;
 100
 101         if (count == 0 ||
 102             (type != PTHREAD_PROCESS_PRIVATE && type != PTHREAD_PROCESS_SHARED))
 103                 return (EINVAL);
 104
 105         barrier->__pthread_barrier_count = count;
 106         barrier->__pthread_barrier_current = count;
 107         barrier->__pthread_barrier_cycle = 0;
 108         barrier->__pthread_barrier_reserved = 0;
 109         (void) mutex_init(mp, type, NULL);
 110         (void) cond_init(cvp, type, NULL);
 111
 112         /*
 113          * This should be at the beginning of the function,
 114          * but for the sake of old broken applications that
 115          * do not have proper alignment for their barriers
 116          * (and don't check the return code from pthread_barrier_init),
 117          * we put it here, after initializing the barrier regardless.
 118          */
 119         if (((uintptr_t)barrier & (_LONG_LONG_ALIGNMENT - 1)) &&
 120             curthread->ul_misaligned == 0)
 121                 return (EINVAL);
 122
 123         return (0);
 124 }
 125
 126 int
 127 pthread_barrier_destroy(pthread_barrier_t *barrier)
 128 {
 129         mutex_t *mp = (mutex_t *)&barrier->__pthread_barrier_lock;
 130         cond_t *cvp = (cond_t *)&barrier->__pthread_barrier_cond;
 131
 132         (void) mutex_destroy(mp);
 133         (void) cond_destroy(cvp);
 134         (void) memset(barrier, -1, sizeof (*barrier));
 135         return (0);
 136 }
 137
 138 /*
 139  * pthread_barrier_wait() is not a cancellation point;
 140  */
 141 int
 142 pthread_barrier_wait(pthread_barrier_t *barrier)
 143 {
 144         mutex_t *mp = (mutex_t *)&barrier->__pthread_barrier_lock;
 145         cond_t *cvp = (cond_t *)&barrier->__pthread_barrier_cond;
 146         uint64_t cycle;
 147         int cancel_state;
 148
 149         (void) mutex_lock(mp);
 150
 151         if (--barrier->__pthread_barrier_current == 0) {
 152                 barrier->__pthread_barrier_cycle++;
 153                 barrier->__pthread_barrier_current =
 154                     barrier->__pthread_barrier_count;
 155                 (void) mutex_unlock(mp);
 156                 (void) cond_broadcast(cvp);
 157                 return (PTHREAD_BARRIER_SERIAL_THREAD);
 158         }
 159
 160         (void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cancel_state);
 161         cycle = barrier->__pthread_barrier_cycle;
 162         do {
 163                 (void) cond_wait(cvp, mp);
 164         } while (cycle == barrier->__pthread_barrier_cycle);
 165         (void) pthread_setcancelstate(cancel_state, NULL);
 166
 167         (void) mutex_unlock(mp);
 168         return (0);
 169 }