glibc/sysdeps/mach/hurd/readdir.c

67 lines
2.2 KiB
C

/* Copyright (C) 1993-2014 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
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stddef.h>
#include <dirent.h>
#include <unistd.h>
#include <endian.h>
#include <assert.h>
/* Read a directory entry from DIRP. */
struct dirent *
__readdir (DIR *dirp)
{
struct dirent64 *entry64 = __readdir64 (dirp);
if (sizeof (struct dirent64) == sizeof (struct dirent))
/* We should in fact just be an alias to readdir64 on this machine. */
return (struct dirent *) entry64;
/* These are all compile-time constants. We know that d_ino is the first
member and that the layout of the following members matches exactly in
both structures. */
assert (offsetof (struct dirent, d_ino) == 0);
assert (offsetof (struct dirent64, d_ino) == 0);
# define MATCH(memb) \
assert (offsetof (struct dirent64, memb) - sizeof (entry64->d_ino) \
== offsetof (struct dirent, memb) - sizeof (ino_t))
MATCH (d_reclen);
MATCH (d_type);
MATCH (d_namlen);
# undef MATCH
if (entry64 == NULL)
return NULL;
struct dirent *const entry = ((void *) (&entry64->d_ino + 1)
- sizeof entry->d_ino);
const ino_t d_ino = entry64->d_ino;
if (d_ino != entry64->d_ino)
{
__set_errno (EOVERFLOW);
return NULL;
}
# if BYTE_ORDER != BIG_ENDIAN /* We just skipped over the zero high word. */
entry->d_ino = d_ino; /* ... or the nonzero low word, swap it. */
# endif
entry->d_reclen -= sizeof entry64->d_ino - sizeof entry->d_ino;
return entry;
}
weak_alias (__readdir, readdir)