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/* Get directory entries. Linux/MIPSn64 LFS version.
Copyright (C) 2018-2019 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>
#include <assert.h>
#include <sys/param.h>
#include <unistd.h>
#include <scratch_buffer.h>
ssize_t
__getdents64 (int fd, void *buf0, size_t nbytes)
{
char *buf = buf0;
#ifdef __NR_getdents64
ssize_t ret = INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
if (ret != -1)
return ret;
#endif
/* Unfortunately getdents64 was only wire-up for MIPS n64 on Linux 3.10.
If syscall is not available it need to fallback to non-LFS one. */
struct kernel_dirent
{
unsigned long d_ino;
unsigned long d_off;
unsigned short int d_reclen;
char d_name[256];
};
const size_t size_diff = (offsetof (struct dirent64, d_name)
- offsetof (struct kernel_dirent, d_name));
size_t red_nbytes = MIN (nbytes
- ((nbytes / (offsetof (struct dirent64, d_name)
+ 14)) * size_diff),
nbytes - size_diff);
struct scratch_buffer tmpbuf;
scratch_buffer_init (&tmpbuf);
if (!scratch_buffer_set_array_size (&tmpbuf, red_nbytes, sizeof (uint8_t)))
INLINE_SYSCALL_ERROR_RETURN_VALUE (ENOMEM);
struct kernel_dirent *skdp, *kdp;
skdp = kdp = tmpbuf.data;
ssize_t retval = INLINE_SYSCALL_CALL (getdents, fd, kdp, red_nbytes);
if (retval == -1)
{
scratch_buffer_free (&tmpbuf);
return -1;
}
off64_t last_offset = -1;
struct dirent64 *dp = (struct dirent64 *) buf;
while ((char *) kdp < (char *) skdp + retval)
{
const size_t alignment = _Alignof (struct dirent64);
/* Since kdp->d_reclen is already aligned for the kernel structure
this may compute a value that is bigger than necessary. */
size_t new_reclen = ((kdp->d_reclen + size_diff + alignment - 1)
& ~(alignment - 1));
if ((char *) dp + new_reclen > buf + nbytes)
{
/* Our heuristic failed. We read too many entries. Reset
the stream. */
assert (last_offset != -1);
__lseek64 (fd, last_offset, SEEK_SET);
if ((char *) dp == buf)
{
scratch_buffer_free (&tmpbuf);
return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
}
break;
}
last_offset = kdp->d_off;
dp->d_ino = kdp->d_ino;
dp->d_off = kdp->d_off;
dp->d_reclen = new_reclen;
dp->d_type = *((char *) kdp + kdp->d_reclen - 1);
memcpy (dp->d_name, kdp->d_name,
kdp->d_reclen - offsetof (struct kernel_dirent, d_name));
dp = (struct dirent64 *) ((char *) dp + new_reclen);
kdp = (struct kernel_dirent *) (((char *) kdp) + kdp->d_reclen);
}
scratch_buffer_free (&tmpbuf);
return (char *) dp - buf;
}
libc_hidden_def (__getdents64)
weak_alias (__getdents64, getdents64)
#if _DIRENT_MATCHES_DIRENT64
strong_alias (__getdents64, __getdents)
#endif
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