seekdir.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static	char	*sccsid = "@(#)seekdir.c	4.1	(ULTRIX)	7/3/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1986 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
/************************************************************************
 *			Modification History				*
 *									*
 *	L. Scott, 09-Jan-1990        					*
 * 0001 always perform lseek; independent of return from telldir	*
 *									*
 ************************************************************************/

#include <sys/param.h>
#include <sys/dir.h>

/*
 * seek to an entry in a directory.
 * Only values returned by "telldir" should be passed to seekdir.
 */
void
seekdir(dirp, tell)
	register DIR *dirp;
	register long tell;
{
	register struct direct *dp;
	register long entno;
	register long base;
	extern long lseek();

	base = tell / dirp->dd_bsize;
	entno = tell % dirp->dd_bsize;
	(void) lseek(dirp->dd_fd, base, 0);
	dirp->dd_loc = 0;
	dirp->dd_entno = 0;
	while (dirp->dd_entno < entno) {
		dp = readdir(dirp);
		if (dp == NULL)
			return;
	}
}