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Diffstat (limited to 'libraries/libldap_r/rmutex.c')
| -rw-r--r-- | libraries/libldap_r/rmutex.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/libraries/libldap_r/rmutex.c b/libraries/libldap_r/rmutex.c new file mode 100644 index 0000000..6099a2a --- /dev/null +++ b/libraries/libldap_r/rmutex.c @@ -0,0 +1,219 @@ +/* $OpenLDAP$ */ +/* 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; +} + |