mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 08:40:07 +00:00
04277e02d7
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
126 lines
4.1 KiB
C
126 lines
4.1 KiB
C
/* Get directory entries. Linux LFS version.
|
|
Copyright (C) 1997-2019 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 (offset == 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)
|
|
{
|
|
/* This is the marker for the first entry. Offset 0 is reserved
|
|
for the first entry (see rewinddir). Here, we use it as a
|
|
marker for the first entry in the buffer. We never actually
|
|
seek to offset 0 because handle_overflow reports the error
|
|
directly, so it does not matter that the offset is incorrect
|
|
if entries have been read from the descriptor before (so that
|
|
the descriptor is not actually at offset 0). */
|
|
__off64_t previous_offset = 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, previous_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;
|
|
previous_offset = offset;
|
|
}
|
|
}
|
|
return retval;
|
|
}
|
|
# endif /* SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_2) */
|
|
#endif /* _DIRENT_MATCHES_DIRENT64 */
|