1997-05-27 01:01:17 +02:00
|
|
|
|
/* Copyright (C) 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
|
|
|
|
|
This file is part of the GNU C Library.
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
1997-05-27 01:01:17 +02:00
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
|
|
|
modify it under the terms of the GNU Library General Public License as
|
|
|
|
|
published by the Free Software Foundation; either version 2 of the
|
|
|
|
|
License, or (at your option) any later version.
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
1997-05-27 01:01:17 +02:00
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
|
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
|
|
|
Library General Public License for more details.
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
1997-05-27 01:01:17 +02:00
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
|
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
|
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
|
|
|
Boston, MA 02111-1307, USA. */
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
|
|
|
|
#include <errno.h>
|
|
|
|
|
#include <stddef.h>
|
|
|
|
|
#include <dirent.h>
|
|
|
|
|
#include <unistd.h>
|
|
|
|
|
#include <sys/types.h>
|
|
|
|
|
#include <stdlib.h>
|
1995-08-28 11:00:05 +02:00
|
|
|
|
#include "dirstream.h"
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
|
|
|
|
/* Internal data structure for telldir and seekdir. */
|
|
|
|
|
struct record
|
|
|
|
|
{
|
|
|
|
|
struct record *next; /* Link in chain. */
|
|
|
|
|
off_t cookie; /* Value returned by `telldir'. */
|
|
|
|
|
off_t pos;
|
|
|
|
|
size_t offset;
|
|
|
|
|
};
|
|
|
|
|
#define NBUCKETS 32
|
|
|
|
|
static struct record *records[32];
|
|
|
|
|
static off_t lastpos;
|
1996-07-26 02:34:28 +02:00
|
|
|
|
__libc_lock_define_initialized(static, lock) /* Locks above data. */
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/* Return the current position of DIRP. */
|
|
|
|
|
off_t
|
1997-05-27 01:01:17 +02:00
|
|
|
|
telldir (dirp)
|
|
|
|
|
DIR *dirp;
|
1995-02-18 02:27:10 +01:00
|
|
|
|
{
|
|
|
|
|
struct record *new;
|
1996-07-09 16:49:13 +02:00
|
|
|
|
off_t pos;
|
|
|
|
|
|
|
|
|
|
__libc_lock_lock (lock);
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
|
|
|
|
new = malloc (sizeof *new);
|
|
|
|
|
if (new == NULL)
|
|
|
|
|
return (off_t) -1;
|
|
|
|
|
|
1996-05-14 01:11:29 +02:00
|
|
|
|
new->pos = dirp->filepos;
|
|
|
|
|
new->offset = dirp->offset;
|
1995-02-18 02:27:10 +01:00
|
|
|
|
new->cookie = ++lastpos;
|
|
|
|
|
new->next = records[new->cookie % NBUCKETS];
|
|
|
|
|
records[new->cookie % NBUCKETS] = new;
|
|
|
|
|
|
1996-07-09 16:49:13 +02:00
|
|
|
|
pos = new->cookie;
|
|
|
|
|
|
|
|
|
|
__libc_lock_unlock (lock);
|
|
|
|
|
|
|
|
|
|
return pos;
|
1995-02-18 02:27:10 +01:00
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/* Seek to position POS in DIRP. */
|
|
|
|
|
void
|
1997-05-27 01:01:17 +02:00
|
|
|
|
seekdir (dirp, pos)
|
|
|
|
|
DIR *dirp;
|
|
|
|
|
__off_t pos;
|
1995-02-18 02:27:10 +01:00
|
|
|
|
{
|
|
|
|
|
struct record *r, **prevr;
|
|
|
|
|
|
1996-07-09 16:49:13 +02:00
|
|
|
|
__libc_lock_lock (lock);
|
|
|
|
|
|
1995-02-18 02:27:10 +01:00
|
|
|
|
for (prevr = &records[pos % NBUCKETS], r = *prevr;
|
|
|
|
|
r != NULL;
|
|
|
|
|
prevr = &r->next, r = r->next)
|
|
|
|
|
if (r->cookie == pos)
|
|
|
|
|
{
|
1996-07-09 16:49:13 +02:00
|
|
|
|
__libc_lock_lock (dirp->__lock);
|
1996-05-14 01:11:29 +02:00
|
|
|
|
if (dirp->filepos != r->pos || dirp->offset != r->offset)
|
1995-02-18 02:27:10 +01:00
|
|
|
|
{
|
1996-05-14 01:11:29 +02:00
|
|
|
|
dirp->size = 0; /* Must read a fresh buffer. */
|
1995-02-18 02:27:10 +01:00
|
|
|
|
/* Move to the saved position. */
|
1996-05-14 01:11:29 +02:00
|
|
|
|
__lseek (dirp->fd, r->pos, SEEK_SET);
|
|
|
|
|
dirp->filepos = r->pos;
|
|
|
|
|
dirp->offset = 0;
|
1995-02-18 02:27:10 +01:00
|
|
|
|
/* Read entries until we reach the saved offset. */
|
1996-05-14 01:11:29 +02:00
|
|
|
|
while (dirp->offset < r->offset)
|
1996-07-09 16:49:13 +02:00
|
|
|
|
{
|
|
|
|
|
struct dirent *scan;
|
|
|
|
|
__libc_lock_unlock (dirp->__lock);
|
|
|
|
|
scan = readdir (dirp);
|
|
|
|
|
__libc_lock_lock (dirp->__lock);
|
|
|
|
|
if (! scan)
|
|
|
|
|
break;
|
|
|
|
|
}
|
1995-02-18 02:27:10 +01:00
|
|
|
|
}
|
1996-07-09 16:49:13 +02:00
|
|
|
|
__libc_lock_unlock (dirp->__lock);
|
1995-02-18 02:27:10 +01:00
|
|
|
|
|
|
|
|
|
/* To prevent leaking memory, cookies returned from telldir
|
|
|
|
|
can only be used once. So free this one's record now. */
|
|
|
|
|
*prevr = r->next;
|
|
|
|
|
free (r);
|
1996-07-09 16:49:13 +02:00
|
|
|
|
break;
|
1995-02-18 02:27:10 +01:00
|
|
|
|
}
|
|
|
|
|
|
1996-07-09 16:49:13 +02:00
|
|
|
|
__libc_lock_unlock (lock);
|
|
|
|
|
|
|
|
|
|
/* If we lost there is no way to indicate it. Oh well. */
|
1995-02-18 02:27:10 +01:00
|
|
|
|
}
|