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/* Copyright (C) 1991-2020 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, see
<https://www.gnu.org/licenses/>. */
#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>
#ifndef __READDIR_R
# define __READDIR_R __readdir_r
# define __GETDENTS __getdents
# define DIRENT_TYPE struct dirent
# define __READDIR_R_ALIAS
#endif
/* Read a directory entry from DIRP. */
int
__READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result)
{
DIRENT_TYPE *dp;
size_t reclen;
const int saved_errno = errno;
int ret;
__libc_lock_lock (dirp->lock);
do
{
if (dirp->offset >= dirp->size)
{
/* We've emptied out our buffer. Refill it. */
size_t maxread;
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
bytes = __GETDENTS (dirp->fd, dirp->data, maxread);
if (bytes <= 0)
{
/* On some systems getdents fails with ENOENT when the
open directory has been rmdir'd already. POSIX.1
requires that we treat this condition like normal EOF. */
if (bytes < 0 && errno == ENOENT)
{
bytes = 0;
__set_errno (saved_errno);
}
if (bytes < 0)
dirp->errcode = errno;
dp = NULL;
break;
}
dirp->size = (size_t) bytes;
/* Reset the offset into the buffer. */
dirp->offset = 0;
}
dp = (DIRENT_TYPE *) &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
#ifdef NAME_MAX
if (reclen > offsetof (DIRENT_TYPE, d_name) + NAME_MAX + 1)
{
/* The record is very long. It could still fit into the
caller-supplied buffer if we can skip padding at the
end. */
size_t namelen = _D_EXACT_NAMLEN (dp);
if (namelen <= NAME_MAX)
reclen = offsetof (DIRENT_TYPE, d_name) + namelen + 1;
else
{
/* The name is too long. Ignore this file. */
dirp->errcode = ENAMETOOLONG;
dp->d_ino = 0;
continue;
}
}
#endif
/* Skip deleted and ignored files. */
}
while (dp->d_ino == 0);
if (dp != NULL)
{
*result = memcpy (entry, dp, reclen);
#ifdef _DIRENT_HAVE_D_RECLEN
entry->d_reclen = reclen;
#endif
ret = 0;
}
else
{
*result = NULL;
ret = dirp->errcode;
}
__libc_lock_unlock (dirp->lock);
return ret;
}
#ifdef __READDIR_R_ALIAS
weak_alias (__readdir_r, readdir_r)
#endif
#undef __READDIR_R
#undef __GETDENTS
#undef DIRENT_TYPE
#undef __READDIR_R_ALIAS
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