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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1997,2007 Oracle. All rights reserved.
*
* $Id: os_flock.c,v 12.14 2007/05/17 15:15:46 bostic Exp $
*/
#include "db_config.h"
#include "db_int.h"
/*
* __os_fdlock --
* Acquire/release a lock on a byte in a file.
*
* PUBLIC: int __os_fdlock __P((DB_ENV *, DB_FH *, off_t, int, int));
*/
int
__os_fdlock(dbenv, fhp, offset, acquire, nowait)
DB_ENV *dbenv;
DB_FH *fhp;
int acquire, nowait;
off_t offset;
{
#ifdef HAVE_FCNTL
struct flock fl;
int ret, t_ret;
DB_ASSERT(dbenv, F_ISSET(fhp, DB_FH_OPENED) && fhp->fd != -1);
if (dbenv != NULL && FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS_ALL))
__db_msg(dbenv,
"fileops: flock %s %s offset %lu",
fhp->name, acquire ? "acquire": "release", (u_long)offset);
fl.l_start = offset;
fl.l_len = 1;
fl.l_type = acquire ? F_WRLCK : F_UNLCK;
fl.l_whence = SEEK_SET;
RETRY_CHK_EINTR_ONLY(
(fcntl(fhp->fd, nowait ? F_SETLK : F_SETLKW, &fl)), ret);
if (ret == 0)
return (0);
if ((t_ret = __os_posix_err(ret)) != EACCES && t_ret != EAGAIN)
__db_syserr(dbenv, ret, "fcntl");
return (t_ret);
#else
COMPQUIET(fhp, NULL);
COMPQUIET(acquire, 0);
COMPQUIET(nowait, 0);
COMPQUIET(offset, 0);
__db_syserr(dbenv, DB_OPNOTSUP, "advisory file locking unavailable");
return (DB_OPNOTSUP);
#endif
}
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