134 lines
4.2 KiB
C
134 lines
4.2 KiB
C
|
#ifndef HAVE_OPENDIR
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Copyright (c) 1983 Regents of the University of California.
|
||
|
|
* All rights reserved.
|
||
|
|
*
|
||
|
|
* Redistribution and use in source and binary forms, with or without
|
||
|
|
* modification, are permitted provided that the following conditions
|
||
|
|
* are met:
|
||
|
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer.
|
||
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
|
* documentation and/or other materials provided with the distribution.
|
||
|
|
* 3. All advertising materials mentioning features or use of this software
|
||
|
|
* must display the following acknowledgement:
|
||
|
|
* This product includes software developed by the University of
|
||
|
|
* California, Berkeley and its contributors.
|
||
|
|
* 4. Neither the name of the University nor the names of its contributors
|
||
|
|
* may be used to endorse or promote products derived from this software
|
||
|
|
* without specific prior written permission.
|
||
|
|
*
|
||
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||
|
|
* SUCH DAMAGE.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
||
|
|
static char sccsid[] = "@(#)telldir.c 5.9 (Berkeley) 2/23/91";
|
||
|
|
#endif /* LIBC_SCCS and not lint */
|
||
|
|
|
||
|
|
#include <sys/param.h>
|
||
|
|
#include <dirent.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The option SINGLEUSE may be defined to say that a telldir
|
||
|
|
* cookie may be used only once before it is freed. This option
|
||
|
|
* is used to avoid having memory usage grow without bound.
|
||
|
|
*/
|
||
|
|
#define SINGLEUSE
|
||
|
|
|
||
|
|
/*
|
||
|
|
* One of these structures is malloced to describe the current directory
|
||
|
|
* position each time telldir is called. It records the current magic
|
||
|
|
* cookie returned by getdirentries and the offset within the buffer
|
||
|
|
* associated with that return value.
|
||
|
|
*/
|
||
|
|
struct ddloc {
|
||
|
|
struct ddloc *loc_next;/* next structure in list */
|
||
|
|
long loc_index; /* key associated with structure */
|
||
|
|
long loc_seek; /* magic cookie returned by getdirentries */
|
||
|
|
long loc_loc; /* offset of entry in buffer */
|
||
|
|
};
|
||
|
|
|
||
|
|
#define NDIRHASH 32 /* Num of hash lists, must be a power of 2 */
|
||
|
|
#define LOCHASH(i) ((i)&(NDIRHASH-1))
|
||
|
|
|
||
|
|
static long dd_loccnt; /* Index of entry for sequential readdir's */
|
||
|
|
static struct ddloc *dd_hash[NDIRHASH]; /* Hash list heads for ddlocs */
|
||
|
|
|
||
|
|
/*
|
||
|
|
* return a pointer into a directory
|
||
|
|
*/
|
||
|
|
long
|
||
|
|
telldir(dirp)
|
||
|
|
const DIR *dirp;
|
||
|
|
{
|
||
|
|
register int index;
|
||
|
|
register struct ddloc *lp;
|
||
|
|
|
||
|
|
if ((lp = (struct ddloc *)malloc(sizeof(struct ddloc))) == NULL)
|
||
|
|
return (-1);
|
||
|
|
index = dd_loccnt++;
|
||
|
|
lp->loc_index = index;
|
||
|
|
lp->loc_seek = dirp->dd_seek;
|
||
|
|
lp->loc_loc = dirp->dd_loc;
|
||
|
|
lp->loc_next = dd_hash[LOCHASH(index)];
|
||
|
|
dd_hash[LOCHASH(index)] = lp;
|
||
|
|
return (index);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* seek to an entry in a directory.
|
||
|
|
* Only values returned by "telldir" should be passed to seekdir.
|
||
|
|
*/
|
||
|
|
void
|
||
|
|
_seekdir(dirp, loc)
|
||
|
|
register DIR *dirp;
|
||
|
|
long loc;
|
||
|
|
{
|
||
|
|
register struct ddloc *lp;
|
||
|
|
register struct ddloc **prevlp;
|
||
|
|
struct dirent *dp;
|
||
|
|
extern long lseek();
|
||
|
|
|
||
|
|
prevlp = &dd_hash[LOCHASH(loc)];
|
||
|
|
lp = *prevlp;
|
||
|
|
while (lp != NULL) {
|
||
|
|
if (lp->loc_index == loc)
|
||
|
|
break;
|
||
|
|
prevlp = &lp->loc_next;
|
||
|
|
lp = lp->loc_next;
|
||
|
|
}
|
||
|
|
if (lp == NULL)
|
||
|
|
return;
|
||
|
|
if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
|
||
|
|
goto found;
|
||
|
|
(void) lseek(dirp->dd_fd, lp->loc_seek, 0);
|
||
|
|
dirp->dd_seek = lp->loc_seek;
|
||
|
|
dirp->dd_loc = 0;
|
||
|
|
while (dirp->dd_loc < lp->loc_loc) {
|
||
|
|
dp = readdir(dirp);
|
||
|
|
if (dp == NULL)
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
found:
|
||
|
|
#ifdef SINGLEUSE
|
||
|
|
*prevlp = lp->loc_next;
|
||
|
|
free((caddr_t)lp);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* ! HAVE_OPENDIR */
|