usr/src/lib/libnisdb/nisdb_rw.h

   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, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2001 by Sun Microsystems, Inc.
  24  * All rights reserved.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #ifndef _NISDB_RW_H
  30 #define _NISDB_RW_H
  31
  32 #include <pthread.h>
  33 #include <thread.h>
  34 #include <synch.h>
  35 #include <stdlib.h>
  36 #include <malloc.h>
  37 #include <sys/errno.h>
  38
  39 #ifdef  __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 #define INV_PTHREAD_ID  0
  44
  45 /*
  46  * DEFAULTNISDBRWLOCK_RW is the default initializer that does _not_
  47  * force read lock requests to write locks, while DEFAULTNISDBRWLOCK_W
  48  * does force all locks to be exclusive.
  49  *
  50  * Locks should be initialized DEFAULTNISDBRWLOCK_W until it's been
  51  * determined that non-exclusive locking can be safely used; see
  52  * comments in __nisdb_rwinit() in nisdb_rw.c.
  53  */
  54 #define DEFAULTNISDBRWLOCK_RW   {DEFAULTMUTEX, DEFAULTCV, 0, 0, \
  55                                         0, {INV_PTHREAD_ID, 0, 0, 0}, \
  56                                         0, 0, {INV_PTHREAD_ID, 0, 0, 0}}
  57
  58 #define DEFAULTNISDBRWLOCK_W    {DEFAULTMUTEX, DEFAULTCV, 0, 1, \
  59                                         0, {INV_PTHREAD_ID, 0, 0, 0}, \
  60                                         0, 0, {INV_PTHREAD_ID, 0, 0, 0}}
  61
  62 #define DEFAULTNISDBRWLOCK      DEFAULTNISDBRWLOCK_W
  63
  64 /*
  65  * The value used for the 'force_write' field initialization in
  66  * __nisdb_rwinit(). Should be one unless it's been determined that
  67  * read locks can safely be used in for _all_ locks initialized
  68  * by __nisdb_rwinit().
  69  */
  70 #define NISDB_FORCE_WRITE       1
  71
  72 #ifdef  NISDB_MT_DEBUG
  73
  74 #define DECLMUTEXLOCK(var)      pthread_mutex_t var ## _pmutex = \
  75                                         PTHREAD_MUTEX_INITIALIZER; \
  76                                 pthread_t var ## _owner = INV_PTHREAD_ID
  77 #define USEMUTEXLOCK(var)       extern pthread_mutex_t var ## _pmutex; \
  78                                 extern pthread_t var ## _owner
  79 #define STRUCTMUTEXLOCK(var)    pthread_mutex_t var ## _pmutex; \
  80                                 pthread_t var ## _owner
  81 #define INITMUTEX(var)          (void) pthread_mutex_init(&var ## _pmutex, 0)
  82 #define MUTEXLOCK(var, msg)     if (var ## _owner != pthread_self()) { \
  83                                         pthread_mutex_lock(&var ## _pmutex); \
  84                                         var ## _owner = pthread_self(); \
  85                                 } else \
  86                                         abort();
  87 #define MUTEXUNLOCK(var, msg)   if (var ## _owner == pthread_self()) { \
  88                                         var ## _owner = INV_PTHREAD_ID; \
  89                                         pthread_mutex_unlock(&var ## _pmutex);\
  90                                 } else \
  91                                         abort();
  92 #define ASSERTMUTEXHELD(var)    if (var ## _owner != pthread_self()) \
  93                                         abort();
  94
  95 #define DECLRWLOCK(var)         __nisdb_rwlock_t var ## _rwlock = \
  96                                                 DEFAULTNISDBRWLOCK
  97 #define USERWLOCK(var)          extern __nisdb_rwlock_t var ## _rwlock
  98 #define STRUCTRWLOCK(var)       __nisdb_rwlock_t var ## _rwlock
  99 #define INITRW(var)             (void) __nisdb_rwinit(&var ## _rwlock)
 100 #define READLOCKOK(var)         (void) __nisdb_rw_readlock_ok(&var ## _rwlock)
 101 #define RLOCK(var)              __nisdb_rlock(&var ## _rwlock)
 102 #define WLOCK(var)              __nisdb_wlock(&var ## _rwlock)
 103 #define TRYWLOCK(var)           __nisdb_wlock_trylock(&var ## _rwlock, 1)
 104 #define RULOCK(var)             __nisdb_rulock(&var ## _rwlock)
 105 #define WULOCK(var)             __nisdb_wulock(&var ## _rwlock)
 106 #define DESTROYRW(var)          __nisdb_destroy_lock(&var ## _rwlock)
 107 #define ASSERTWHELD(var)        if (__nisdb_assert_wheld(&var ## _rwlock) \
 108                                         != 0) \
 109                                         abort();
 110 #define ASSERTRHELD(var)        if (__nisdb_assert_rheld(&var ## _rwlock) \
 111                                         != 0) \
 112                                         abort();
 113
 114 #else   /* NISDB_MT_DEBUG */
 115
 116 #define DECLMUTEXLOCK(var)      pthread_mutex_t var ## _pmutex = \
 117                                         PTHREAD_MUTEX_INITIALIZER
 118 #define USEMUTEXLOCK(var)       extern pthread_mutex_t var ## _pmutex
 119 #define STRUCTMUTEXLOCK(var)    pthread_mutex_t var ## _pmutex
 120 #define INITMUTEX(var)          (void) pthread_mutex_init(&var ## _pmutex, 0)
 121 #define MUTEXLOCK(var, msg)     pthread_mutex_lock(&var ## _pmutex)
 122 #define MUTEXUNLOCK(var, msg)   pthread_mutex_unlock(&var ## _pmutex)
 123
 124 #define DECLRWLOCK(var)         __nisdb_rwlock_t var ## _rwlock = \
 125                                                 DEFAULTNISDBRWLOCK
 126 #define USERWLOCK(var)          extern __nisdb_rwlock_t var ## _rwlock
 127 #define STRUCTRWLOCK(var)       __nisdb_rwlock_t var ## _rwlock
 128 #define INITRW(var)             (void) __nisdb_rwinit(&var ## _rwlock)
 129 #define READLOCKOK(var)         (void) __nisdb_rw_readlock_ok(&var ## _rwlock)
 130 #define RLOCK(var)              __nisdb_rlock(&var ## _rwlock)
 131 #define WLOCK(var)              __nisdb_wlock(&var ## _rwlock)
 132 #define TRYWLOCK(var)           __nisdb_wlock_trylock(&var ## _rwlock, 1)
 133 #define RULOCK(var)             __nisdb_rulock(&var ## _rwlock)
 134 #define WULOCK(var)             __nisdb_wulock(&var ## _rwlock)
 135 #define DESTROYRW(var)          __nisdb_destroy_lock(&var ## _rwlock)
 136 #define ASSERTMUTEXHELD(var)
 137 #define ASSERTWHELD(var)
 138 #define ASSERTRHELD(var)
 139
 140 #endif  /* NISDB_MT_DEBUG */
 141
 142 /* Nesting-safe RW locking */
 143 typedef struct __nisdb_rwlock {
 144         pthread_t               id;     /* Which thread */
 145         uint32_t                count;  /* Lock depth for thread */
 146         uint32_t                wait;   /* Blocked on mutex */
 147         struct __nisdb_rwlock   *next;  /* Next reader record */
 148 } __nisdb_rl_t;
 149
 150 typedef struct {
 151         mutex_t         mutex;          /* Exclusive access to structure */
 152         cond_t          cv;             /* CV for signaling */
 153         uint32_t        destroyed;      /* Set if lock has been destroyed */
 154         uint32_t        force_write;    /* Set if read locks forced to write */
 155         uint32_t        writer_count;   /* Number of writer threads [0, 1] */
 156         __nisdb_rl_t    writer;         /* Writer record */
 157         uint32_t        reader_count;   /* # of reader threads [0, N] */
 158         uint32_t        reader_blocked; /* # of readers blocked on mutex */
 159         __nisdb_rl_t    reader;         /* List of reader records */
 160 } __nisdb_rwlock_t;
 161
 162 extern int              __nisdb_rwinit(__nisdb_rwlock_t *);
 163 extern int              __nisdb_rw_readlock_ok(__nisdb_rwlock_t *rw);
 164 extern int              __nisdb_rw_force_writelock(__nisdb_rwlock_t *rw);
 165 extern int              __nisdb_wlock(__nisdb_rwlock_t *);
 166 extern int              __nisdb_wlock_trylock(__nisdb_rwlock_t *, int);
 167 extern int              __nisdb_rlock(__nisdb_rwlock_t *);
 168 extern int              __nisdb_wulock(__nisdb_rwlock_t *);
 169 extern int              __nisdb_rulock(__nisdb_rwlock_t *);
 170 extern int              __nisdb_assert_wheld(__nisdb_rwlock_t *);
 171 extern int              __nisdb_assert_rheld(__nisdb_rwlock_t *);
 172 extern int              __nisdb_destroy_lock(__nisdb_rwlock_t *);
 173 extern void             __nisdb_lock_report(__nisdb_rwlock_t *rw);
 174
 175 #ifdef  __cplusplus
 176 }
 177 #endif
 178
 179 #endif  /* _NISDB_RW_H */