os_truncate.c

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/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2004
 *	Sleepycat Software.  All rights reserved.
 *
 * $Id: os_truncate.c,v 11.7 2004/09/17 22:00:31 mjc Exp $
 */

#include "db_config.h"

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <string.h>
#include <unistd.h>
#endif

#include "db_int.h"

/*
 * __os_truncate --
 *	Truncate the file.
 *
 * PUBLIC: int __os_truncate __P((DB_ENV *, DB_FH *, db_pgno_t, u_int32_t));
 */
int
__os_truncate(dbenv, fhp, pgno, pgsize)
	DB_ENV *dbenv;
	DB_FH *fhp;
	db_pgno_t pgno;
	u_int32_t pgsize;
{
	off_t offset;
	int ret;

	/*
	 * Truncate a file so that "pgno" is discarded from the end of the
	 * file.
	 */
	offset = (off_t)pgsize * pgno;

	if (DB_GLOBAL(j_ftruncate) != NULL)
		ret = DB_GLOBAL(j_ftruncate)(fhp->fd, offset);
	else {
#ifdef HAVE_FTRUNCATE
		RETRY_CHK((ftruncate(fhp->fd, offset)), ret);
#else
		ret = DB_OPNOTSUP;
#endif
	}

	if (ret != 0)
		__db_err(dbenv,
		    "ftruncate: %lu: %s", (u_long)offset, strerror(ret));

	return (ret);
}