ef80a53495
telldir positions. This will allow (future) locking on a
per-DIR basis (for MT-safety). For now, this change does
the following:
o Remove the hash table from telldir.c. Recode to use queue
macros.
o Remove 'const' from 'telldir(const DIR *)'.
o Remove 'register' variables as suggested in a recent
thread.
No response from: -current
136 lines
4.0 KiB
C
136 lines
4.0 KiB
C
/*
|
|
* Copyright (c) 1983, 1993
|
|
* The 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.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
static char sccsid[] = "@(#)telldir.c 8.1 (Berkeley) 6/4/93";
|
|
#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 {
|
|
LIST_ENTRY(_ddloc) loc_lqe; /* entry 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 */
|
|
};
|
|
|
|
/*
|
|
* return a pointer into a directory
|
|
*/
|
|
long
|
|
telldir(dirp)
|
|
DIR *dirp;
|
|
{
|
|
struct _ddloc *lp;
|
|
|
|
if ((lp = (struct _ddloc *)malloc(sizeof(struct _ddloc))) == NULL)
|
|
return (-1);
|
|
lp->loc_index = dirp->dd_loccnt++;
|
|
lp->loc_seek = dirp->dd_seek;
|
|
lp->loc_loc = dirp->dd_loc;
|
|
LIST_INSERT_HEAD(&dirp->dd_locq, lp, loc_lqe);
|
|
return (lp->loc_index);
|
|
}
|
|
|
|
/*
|
|
* seek to an entry in a directory.
|
|
* Only values returned by "telldir" should be passed to seekdir.
|
|
*/
|
|
void
|
|
_seekdir(dirp, loc)
|
|
DIR *dirp;
|
|
long loc;
|
|
{
|
|
struct _ddloc *lp;
|
|
struct dirent *dp;
|
|
|
|
LIST_FOREACH(lp, &dirp->dd_locq, loc_lqe) {
|
|
if (lp->loc_index == loc)
|
|
break;
|
|
}
|
|
if (lp == NULL)
|
|
return;
|
|
if (lp->loc_loc == dirp->dd_loc && lp->loc_seek == dirp->dd_seek)
|
|
goto found;
|
|
(void) lseek(dirp->dd_fd, (off_t)lp->loc_seek, SEEK_SET);
|
|
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
|
|
LIST_REMOVE(lp, loc_lqe);
|
|
free((caddr_t)lp);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Reclaim memory for telldir cookies which weren't used.
|
|
*/
|
|
void
|
|
_reclaim_telldir(dirp)
|
|
DIR *dirp;
|
|
{
|
|
struct _ddloc *lp;
|
|
struct _ddloc *templp;
|
|
|
|
lp = LIST_FIRST(&dirp->dd_locq);
|
|
while (lp != NULL) {
|
|
templp = lp;
|
|
lp = LIST_NEXT(lp, loc_lqe);
|
|
free(templp);
|
|
}
|
|
LIST_INIT(&dirp->dd_locq);
|
|
}
|