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/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 2006-2021 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
/* This work was initially developed by Howard Chu for inclusion
* in OpenLDAP Software.
*/
/*
* This is an implementation of recursive mutexes.
*/
#include "portable.h"
#include <ac/stdlib.h>
#include <ac/errno.h>
#include <ac/string.h>
#include <ac/time.h>
#include "ldap-int.h"
#include "ldap_pvt_thread.h" /* Get the thread interface */
struct ldap_int_thread_rmutex_s {
ldap_pvt_thread_mutex_t ltrm_mutex;
ldap_pvt_thread_cond_t ltrm_cond;
ldap_pvt_thread_t ltrm_owner;
int ltrm_valid;
#define LDAP_PVT_THREAD_RMUTEX_VALID 0x0cdb
int ltrm_depth;
int ltrm_waits;
};
static const ldap_pvt_thread_t tid_zero;
int
ldap_pvt_thread_rmutex_init( ldap_pvt_thread_rmutex_t *rmutex )
{
struct ldap_int_thread_rmutex_s *rm;
assert( rmutex != NULL );
rm = (struct ldap_int_thread_rmutex_s *) LDAP_CALLOC( 1,
sizeof( struct ldap_int_thread_rmutex_s ) );
if ( !rm )
return LDAP_NO_MEMORY;
/* we should check return results */
ldap_pvt_thread_mutex_init( &rm->ltrm_mutex );
ldap_pvt_thread_cond_init( &rm->ltrm_cond );
rm->ltrm_valid = LDAP_PVT_THREAD_RMUTEX_VALID;
*rmutex = rm;
return 0;
}
int
ldap_pvt_thread_rmutex_destroy( ldap_pvt_thread_rmutex_t *rmutex )
{
struct ldap_int_thread_rmutex_s *rm;
assert( rmutex != NULL );
rm = *rmutex;
assert( rm != NULL );
assert( rm->ltrm_valid == LDAP_PVT_THREAD_RMUTEX_VALID );
if( rm->ltrm_valid != LDAP_PVT_THREAD_RMUTEX_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rm->ltrm_mutex );
assert( rm->ltrm_depth >= 0 );
assert( rm->ltrm_waits >= 0 );
/* in use? */
if( rm->ltrm_depth > 0 || rm->ltrm_waits > 0 ) {
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
return LDAP_PVT_THREAD_EBUSY;
}
rm->ltrm_valid = 0;
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
ldap_pvt_thread_mutex_destroy( &rm->ltrm_mutex );
ldap_pvt_thread_cond_destroy( &rm->ltrm_cond );
LDAP_FREE(rm);
*rmutex = NULL;
return 0;
}
int ldap_pvt_thread_rmutex_lock( ldap_pvt_thread_rmutex_t *rmutex,
ldap_pvt_thread_t owner )
{
struct ldap_int_thread_rmutex_s *rm;
assert( rmutex != NULL );
rm = *rmutex;
assert( rm != NULL );
assert( rm->ltrm_valid == LDAP_PVT_THREAD_RMUTEX_VALID );
if( rm->ltrm_valid != LDAP_PVT_THREAD_RMUTEX_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rm->ltrm_mutex );
assert( rm->ltrm_depth >= 0 );
assert( rm->ltrm_waits >= 0 );
if( rm->ltrm_depth > 0 ) {
/* already locked */
if ( !ldap_pvt_thread_equal( rm->ltrm_owner, owner )) {
rm->ltrm_waits++;
do {
ldap_pvt_thread_cond_wait( &rm->ltrm_cond,
&rm->ltrm_mutex );
} while( rm->ltrm_depth > 0 );
rm->ltrm_waits--;
assert( rm->ltrm_waits >= 0 );
rm->ltrm_owner = owner;
}
} else {
rm->ltrm_owner = owner;
}
rm->ltrm_depth++;
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
return 0;
}
int ldap_pvt_thread_rmutex_trylock( ldap_pvt_thread_rmutex_t *rmutex,
ldap_pvt_thread_t owner )
{
struct ldap_int_thread_rmutex_s *rm;
assert( rmutex != NULL );
rm = *rmutex;
assert( rm != NULL );
assert( rm->ltrm_valid == LDAP_PVT_THREAD_RMUTEX_VALID );
if( rm->ltrm_valid != LDAP_PVT_THREAD_RMUTEX_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rm->ltrm_mutex );
assert( rm->ltrm_depth >= 0 );
assert( rm->ltrm_waits >= 0 );
if( rm->ltrm_depth > 0 ) {
if ( !ldap_pvt_thread_equal( owner, rm->ltrm_owner )) {
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
return LDAP_PVT_THREAD_EBUSY;
}
} else {
rm->ltrm_owner = owner;
}
rm->ltrm_depth++;
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
return 0;
}
int ldap_pvt_thread_rmutex_unlock( ldap_pvt_thread_rmutex_t *rmutex,
ldap_pvt_thread_t owner )
{
struct ldap_int_thread_rmutex_s *rm;
assert( rmutex != NULL );
rm = *rmutex;
assert( rm != NULL );
assert( rm->ltrm_valid == LDAP_PVT_THREAD_RMUTEX_VALID );
if( rm->ltrm_valid != LDAP_PVT_THREAD_RMUTEX_VALID )
return LDAP_PVT_THREAD_EINVAL;
ldap_pvt_thread_mutex_lock( &rm->ltrm_mutex );
if( !ldap_pvt_thread_equal( owner, rm->ltrm_owner )) {
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
return LDAP_PVT_THREAD_EINVAL;
}
rm->ltrm_depth--;
if ( !rm->ltrm_depth )
rm->ltrm_owner = tid_zero;
assert( rm->ltrm_depth >= 0 );
assert( rm->ltrm_waits >= 0 );
if ( !rm->ltrm_depth && rm->ltrm_waits ) {
ldap_pvt_thread_cond_signal( &rm->ltrm_cond );
}
ldap_pvt_thread_mutex_unlock( &rm->ltrm_mutex );
return 0;
}
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