glibc/sysdeps/unix/readdir_r.c

109 lines
2.7 KiB
C

/* Copyright (C) 1991, 92, 93, 94, 95, 96 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
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. */
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <string.h>
#include <dirent.h>
#include <unistd.h>
#include <sys/types.h>
#include <assert.h>
#include <dirstream.h>
/* Read a directory entry from DIRP. */
int
__readdir_r (DIR *dirp, struct dirent *entry, struct dirent **result)
{
struct dirent *dp;
__libc_lock_lock (dirp->lock);
do
{
size_t reclen;
if (dirp->offset >= dirp->size)
{
/* We've emptied out our buffer. Refill it. */
size_t maxread;
off_t base;
ssize_t bytes;
#ifndef _DIRENT_HAVE_D_RECLEN
/* Fixed-size struct; must read one at a time (see below). */
maxread = sizeof *dp;
#else
maxread = dirp->allocation;
#endif
base = dirp->filepos;
bytes = __getdirentries (dirp->fd, dirp->data, maxread, &base);
if (bytes <= 0)
{
dp = NULL;
break;
}
dirp->size = (size_t) bytes;
/* Reset the offset into the buffer. */
dirp->offset = 0;
}
dp = (struct dirent *) &dirp->data[dirp->offset];
#ifdef _DIRENT_HAVE_D_RECLEN
reclen = dp->d_reclen;
#else
/* The only version of `struct dirent' that lacks `d_reclen'
is fixed-size. */
assert (sizeof dp->d_name > 1);
reclen = sizeof *dp;
/* The name is not terminated if it is the largest possible size.
Clobber the following byte to ensure proper null termination. We
read just one entry at a time above so we know that byte will not
be used later. */
dp->d_name[sizeof dp->d_name] = '\0';
#endif
dirp->offset += reclen;
#ifdef _DIRENT_HAVE_D_OFF
dirp->filepos = dp->d_off;
#else
dirp->filepos += reclen;
#endif
/* Skip deleted files. */
} while (dp->d_ino == 0);
if (dp != NULL)
{
*entry = *dp;
*result = entry;
}
__libc_lock_unlock (dirp->lock);
return dp != NULL ? 0 : -1;
}
weak_alias (__readdir_r, readdir_r)