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/* Get directory entries. Linux LFS version.
Copyright (C) 1997-2018 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 <string.h>
#include <dirent.h>
#include <errno.h>
/* The kernel struct linux_dirent64 matches the 'struct getdents64' type. */
ssize_t
__getdents64 (int fd, char *buf, size_t nbytes)
{
return INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
}
#if _DIRENT_MATCHES_DIRENT64
strong_alias (__getdents64, __getdents)
#else
# include <shlib-compat.h>
# if SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_2)
# include <olddirent.h>
# include <unistd.h>
static ssize_t
handle_overflow (int fd, __off64_t offset, ssize_t count)
{
/* If this is the first entry in the buffer, we can report the
error. */
if (count == 0)
{
__set_errno (EOVERFLOW);
return -1;
}
/* Otherwise, seek to the overflowing entry, so that the next call
will report the error, and return the data read so far.. */
if (__lseek64 (fd, offset, SEEK_SET) != 0)
return -1;
return count;
}
ssize_t
__old_getdents64 (int fd, char *buf, size_t nbytes)
{
/* We do not move the individual directory entries. This is only
possible if the target type (struct __old_dirent64) is smaller
than the source type. */
_Static_assert (offsetof (struct __old_dirent64, d_name)
<= offsetof (struct dirent64, d_name),
"__old_dirent64 is larger than dirent64");
_Static_assert (__alignof__ (struct __old_dirent64)
<= __alignof__ (struct dirent64),
"alignment of __old_dirent64 is larger than dirent64");
ssize_t retval = INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
if (retval > 0)
{
char *p = buf;
char *end = buf + retval;
while (p < end)
{
struct dirent64 *source = (struct dirent64 *) p;
/* Copy out the fixed-size data. */
__ino_t ino = source->d_ino;
__off64_t offset = source->d_off;
unsigned int reclen = source->d_reclen;
unsigned char type = source->d_type;
/* Check for ino_t overflow. */
if (__glibc_unlikely (ino != source->d_ino))
return handle_overflow (fd, offset, p - buf);
/* Convert to the target layout. Use a separate struct and
memcpy to side-step aliasing issues. */
struct __old_dirent64 result;
result.d_ino = ino;
result.d_off = offset;
result.d_reclen = reclen;
result.d_type = type;
/* Write the fixed-sized part of the result to the
buffer. */
size_t result_name_offset = offsetof (struct __old_dirent64, d_name);
memcpy (p, &result, result_name_offset);
/* Adjust the position of the name if necessary. Copy
everything until the end of the record, including the
terminating NUL byte. */
if (result_name_offset != offsetof (struct dirent64, d_name))
memmove (p + result_name_offset, source->d_name,
reclen - offsetof (struct dirent64, d_name));
p += reclen;
}
}
return retval;
}
# endif /* SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_2) */
#endif /* _DIRENT_MATCHES_DIRENT64 */
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