**
** Does not support cancellation nor does any status checking.
*/
-
-/********************************************************
- * Adapted from:
+/* Adapted from publically available examples for:
* "Programming with Posix Threads"
- * by David R Butenhof
- * Addison-Wesley
- ********************************************************
+ * by David R Butenhof, Addison-Wesley
+ * http://cseng.aw.com/bookpage.taf?ISBN=0-201-63392-2
*/
#include "portable.h"
#include <ac/errno.h>
#include <ac/string.h>
+#include <ac/time.h>
+#include "ldap-int.h"
#include "ldap_pvt_thread.h"
+/*
+ * implementations that provide their own compatible
+ * reader/writer locks define LDAP_THREAD_HAVE_RDWR
+ * in ldap_pvt_thread.h
+ */
+#ifndef LDAP_THREAD_HAVE_RDWR
+
+struct ldap_int_thread_rdwr_s {
+ ldap_pvt_thread_mutex_t ltrw_mutex;
+ ldap_pvt_thread_cond_t ltrw_read; /* wait for read */
+ ldap_pvt_thread_cond_t ltrw_write; /* wait for write */
+ int ltrw_valid;
+#define LDAP_PVT_THREAD_RDWR_VALID 0x0bad
+ int ltrw_r_active;
+ int ltrw_w_active;
+ int ltrw_r_wait;
+ int ltrw_w_wait;
+};
+
int
-ldap_pvt_thread_rdwr_init( ldap_pvt_thread_rdwr_t *rw )
+ldap_pvt_thread_rdwr_init( ldap_pvt_thread_rdwr_t *rwlock )
{
- assert( rw != NULL );
+ struct ldap_int_thread_rdwr_s *rw;
- memset( rw, 0, sizeof(ldap_pvt_thread_rdwr_t) );
+ assert( rwlock != NULL );
+
+ rw = (struct ldap_int_thread_rdwr_s *) LDAP_CALLOC( 1,
+ sizeof( struct ldap_int_thread_rdwr_s ) );
/* we should check return results */
ldap_pvt_thread_mutex_init( &rw->ltrw_mutex );
ldap_pvt_thread_cond_init( &rw->ltrw_write );
rw->ltrw_valid = LDAP_PVT_THREAD_RDWR_VALID;
+
+ *rwlock = rw;
return 0;
}
int
-ldap_pvt_thread_rdwr_destroy( ldap_pvt_thread_rdwr_t *rw )
+ldap_pvt_thread_rdwr_destroy( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
/* active threads? */
- if( rw->ltrw_r_active > 0 || rw->ltrw_w_active > 1) {
+ if( rw->ltrw_r_active > 0 || rw->ltrw_w_active > 0) {
ldap_pvt_thread_mutex_unlock( &rw->ltrw_mutex );
return LDAP_PVT_THREAD_EBUSY;
}
ldap_pvt_thread_cond_destroy( &rw->ltrw_read );
ldap_pvt_thread_cond_destroy( &rw->ltrw_write );
+ LDAP_FREE(rw);
+ *rwlock = NULL;
return 0;
}
-int ldap_pvt_thread_rdwr_rlock( ldap_pvt_thread_rdwr_t *rw )
+int ldap_pvt_thread_rdwr_rlock( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
- if( rw->ltrw_w_active > 1 ) {
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
+ if( rw->ltrw_w_active > 0 ) {
/* writer is active */
rw->ltrw_r_wait++;
do {
ldap_pvt_thread_cond_wait(
&rw->ltrw_read, &rw->ltrw_mutex );
- } while( rw->ltrw_w_active > 1 );
+ } while( rw->ltrw_w_active > 0 );
rw->ltrw_r_wait--;
+ assert( rw->ltrw_r_wait >= 0 );
}
rw->ltrw_r_active++;
return 0;
}
-int ldap_pvt_thread_rdwr_rtrylock( ldap_pvt_thread_rdwr_t *rw )
+int ldap_pvt_thread_rdwr_rtrylock( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
- if( rw->ltrw_w_active > 1) {
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
+ if( rw->ltrw_w_active > 0) {
ldap_pvt_thread_mutex_unlock( &rw->ltrw_mutex );
return LDAP_PVT_THREAD_EBUSY;
}
return 0;
}
-int ldap_pvt_thread_rdwr_runlock( ldap_pvt_thread_rdwr_t *rw )
+int ldap_pvt_thread_rdwr_runlock( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
rw->ltrw_r_active--;
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
if (rw->ltrw_r_active == 0 && rw->ltrw_w_wait > 0 ) {
ldap_pvt_thread_cond_signal( &rw->ltrw_write );
}
return 0;
}
-int ldap_pvt_thread_rdwr_wlock( ldap_pvt_thread_rdwr_t *rw )
+int ldap_pvt_thread_rdwr_wlock( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
if ( rw->ltrw_w_active > 0 || rw->ltrw_r_active > 0 ) {
rw->ltrw_w_wait++;
} while ( rw->ltrw_w_active > 0 || rw->ltrw_r_active > 0 );
rw->ltrw_w_wait--;
+ assert( rw->ltrw_w_wait >= 0 );
}
rw->ltrw_w_active++;
return 0;
}
-int ldap_pvt_thread_rdwr_wtrylock( ldap_pvt_thread_rdwr_t *rw )
+int ldap_pvt_thread_rdwr_wtrylock( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
ldap_pvt_thread_mutex_lock( &rw->ltrw_mutex );
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
if ( rw->ltrw_w_active > 0 || rw->ltrw_r_active > 0 ) {
ldap_pvt_thread_mutex_unlock( &rw->ltrw_mutex );
return LDAP_PVT_THREAD_EBUSY;
return 0;
}
-int ldap_pvt_thread_rdwr_wunlock( ldap_pvt_thread_rdwr_t *rw )
+int ldap_pvt_thread_rdwr_wunlock( ldap_pvt_thread_rdwr_t *rwlock )
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
rw->ltrw_w_active--;
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
+
if (rw->ltrw_r_wait > 0) {
ldap_pvt_thread_cond_broadcast( &rw->ltrw_read );
return 0;
}
-#ifdef LDAP_DEBUG
+#ifdef LDAP_RDWR_DEBUG
/* just for testing,
* return 0 if false, suitable for assert(ldap_pvt_thread_rdwr_Xchk(rdwr))
* a lock are caught.
*/
-int ldap_pvt_thread_rdwr_readers(ldap_pvt_thread_rdwr_t *rw)
+int ldap_pvt_thread_rdwr_readers(ldap_pvt_thread_rdwr_t *rwlock)
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
return( rw->ltrw_r_active );
}
-int ldap_pvt_thread_rdwr_writers(ldap_pvt_thread_rdwr_t *rw)
+int ldap_pvt_thread_rdwr_writers(ldap_pvt_thread_rdwr_t *rwlock)
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
return( rw->ltrw_w_active );
}
-int ldap_pvt_thread_rdwr_active(ldap_pvt_thread_rdwr_t *rw)
+int ldap_pvt_thread_rdwr_active(ldap_pvt_thread_rdwr_t *rwlock)
{
+ struct ldap_int_thread_rdwr_s *rw;
+
+ assert( rwlock != NULL );
+ rw = *rwlock;
+
assert( rw != NULL );
assert( rw->ltrw_valid == LDAP_PVT_THREAD_RDWR_VALID );
+ assert( rw->ltrw_w_active >= 0 );
+ assert( rw->ltrw_w_wait >= 0 );
+ assert( rw->ltrw_r_active >= 0 );
+ assert( rw->ltrw_r_wait >= 0 );
return(ldap_pvt_thread_rdwr_readers(rw) +
ldap_pvt_thread_rdwr_writers(rw));
}
#endif /* LDAP_DEBUG */
+
+#endif /* LDAP_THREAD_HAVE_RDWR */