#include "db_config.h"
#ifndef lint
static const char revid[] = "$Id: mut_fcntl.c,v 1.2 2004/03/30 01:23:45 jtownsen Exp $";
#endif
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#endif
#include "db_int.h"
int
__db_fcntl_mutex_init(dbenv, mutexp, offset)
DB_ENV *dbenv;
DB_MUTEX *mutexp;
u_int32_t offset;
{
u_int32_t save;
save = F_ISSET(mutexp, MUTEX_MPOOL);
memset(mutexp, 0, sizeof(*mutexp));
F_SET(mutexp, save);
if (F_ISSET(dbenv, DB_ENV_PRIVATE)) {
F_SET(mutexp, MUTEX_IGNORE);
return (0);
}
mutexp->off = offset;
#ifdef HAVE_MUTEX_SYSTEM_RESOURCES
mutexp->reg_off = INVALID_ROFF;
#endif
F_SET(mutexp, MUTEX_INITED);
return (0);
}
int
__db_fcntl_mutex_lock(dbenv, mutexp)
DB_ENV *dbenv;
DB_MUTEX *mutexp;
{
struct flock k_lock;
int locked, ms, waited;
if (F_ISSET(dbenv, DB_ENV_NOLOCKING))
return (0);
k_lock.l_whence = SEEK_SET;
k_lock.l_start = mutexp->off;
k_lock.l_len = 1;
for (locked = waited = 0;;) {
for (ms = 1; mutexp->pid != 0;) {
waited = 1;
__os_yield(NULL, ms * USEC_PER_MS);
if ((ms <<= 1) > MS_PER_SEC)
ms = MS_PER_SEC;
}
k_lock.l_type = F_WRLCK;
if (fcntl(dbenv->lockfhp->fd, F_SETLKW, &k_lock))
return (__os_get_errno());
if (mutexp->pid == 0) {
locked = 1;
__os_id(&mutexp->pid);
}
k_lock.l_type = F_UNLCK;
if (fcntl(dbenv->lockfhp->fd, F_SETLK, &k_lock))
return (__os_get_errno());
if (locked)
break;
}
if (waited)
++mutexp->mutex_set_wait;
else
++mutexp->mutex_set_nowait;
return (0);
}
int
__db_fcntl_mutex_unlock(dbenv, mutexp)
DB_ENV *dbenv;
DB_MUTEX *mutexp;
{
if (F_ISSET(dbenv, DB_ENV_NOLOCKING))
return (0);
#ifdef DIAGNOSTIC
#define MSG "mutex_unlock: ERROR: released lock that was unlocked\n"
#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif
if (mutexp->pid == 0)
write(STDERR_FILENO, MSG, sizeof(MSG) - 1);
#endif
mutexp->pid = 0;
return (0);
}
int
__db_fcntl_mutex_destroy(mutexp)
DB_MUTEX *mutexp;
{
COMPQUIET(mutexp, NULL);
return (0);
}