glibc/io/readlinkat.c

/* Copyright (C) 2005-2013 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 <fcntl.h>
#include <unistd.h>

/* Read the contents of the symbolic link PATH relative to FD into no
   more than LEN bytes of BUF.  The contents are not null-terminated.
   Returns the number of characters read, or -1 for errors.  */
ssize_t
readlinkat (fd, path, buf, len)
     int fd;
     const char *path;
     char *buf;
     size_t len;
{
  if (path == NULL)
    {
      __set_errno (EINVAL);
      return -1;
    }

  if (fd != AT_FDCWD && fd < 0 && *path != '/')
    {
      __set_errno (EBADF);
      return -1;
    }

  __set_errno (ENOSYS);
  return -1;
}
stub_warning (readlinkat)
libc_hidden_def (readlinkat)