mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-18 19:10:06 +00:00
41bdb6e20c
2001-07-06 Paul Eggert <eggert@twinsun.com> * manual/argp.texi: Remove ignored LGPL copyright notice; it's not appropriate for documentation anyway. * manual/libc-texinfo.sh: "Library General Public License" -> "Lesser General Public License". 2001-07-06 Andreas Jaeger <aj@suse.de> * All files under GPL/LGPL version 2: Place under LGPL version 2.1.
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
/* Copyright (C) 1994, 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
|
||
This file is part of the GNU C Library.
|
||
|
||
The GNU C Library is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU Lesser General Public
|
||
License as published by the Free Software Foundation; either
|
||
version 2.1 of the License, or (at your option) any later version.
|
||
|
||
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
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public
|
||
License along with the GNU C Library; if not, write to the Free
|
||
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
||
02111-1307 USA. */
|
||
|
||
#include <errno.h>
|
||
#include <stddef.h>
|
||
#include <dirent.h>
|
||
#include <unistd.h>
|
||
#include <sys/types.h>
|
||
#include <stdlib.h>
|
||
#include "dirstream.h"
|
||
|
||
/* 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;
|
||
__libc_lock_define_initialized(static, lock) /* Locks above data. */
|
||
|
||
|
||
/* Return the current position of DIRP. */
|
||
long int
|
||
telldir (dirp)
|
||
DIR *dirp;
|
||
{
|
||
struct record *new;
|
||
long int pos;
|
||
|
||
new = malloc (sizeof *new);
|
||
if (new == NULL)
|
||
return -1l;
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
new->pos = dirp->filepos;
|
||
new->offset = dirp->offset;
|
||
new->cookie = ++lastpos;
|
||
new->next = records[new->cookie % NBUCKETS];
|
||
records[new->cookie % NBUCKETS] = new;
|
||
|
||
pos = new->cookie;
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return pos;
|
||
}
|
||
|
||
|
||
|
||
/* Seek to position POS in DIRP. */
|
||
void
|
||
seekdir (dirp, pos)
|
||
DIR *dirp;
|
||
long int pos;
|
||
{
|
||
struct record *r, **prevr;
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
for (prevr = &records[pos % NBUCKETS], r = *prevr;
|
||
r != NULL;
|
||
prevr = &r->next, r = r->next)
|
||
if (r->cookie == pos)
|
||
{
|
||
__libc_lock_lock (dirp->__lock);
|
||
if (dirp->filepos != r->pos || dirp->offset != r->offset)
|
||
{
|
||
dirp->size = 0; /* Must read a fresh buffer. */
|
||
/* Move to the saved position. */
|
||
__lseek (dirp->fd, r->pos, SEEK_SET);
|
||
dirp->filepos = r->pos;
|
||
dirp->offset = 0;
|
||
/* Read entries until we reach the saved offset. */
|
||
while (dirp->offset < r->offset)
|
||
{
|
||
struct dirent *scan;
|
||
__libc_lock_unlock (dirp->__lock);
|
||
scan = readdir (dirp);
|
||
__libc_lock_lock (dirp->__lock);
|
||
if (! scan)
|
||
break;
|
||
}
|
||
}
|
||
__libc_lock_unlock (dirp->__lock);
|
||
|
||
/* 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);
|
||
break;
|
||
}
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
/* If we lost there is no way to indicate it. Oh well. */
|
||
}
|