text: /* Copyright (C) 1993-2015 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 <unistd.h>
  #include <hurd.h>
  #include <hurd/fd.h>
  #include <string.h>
  
  error_t
  _hurd_fd_read (struct hurd_fd *fd, void *buf, size_t *nbytes, loff_t offset)
  {
    error_t err;
    char *data;
    mach_msg_type_number_t nread;
  
    error_t readfd (io_t port)
      {
        return __io_read (port, &data, &nread, offset, *nbytes);
      }
  
    data = buf;
    nread = *nbytes;
    if (err = HURD_FD_PORT_USE (fd, _hurd_ctty_input (port, ctty, readfd)))
      return err;
  
    if (data != buf)
      {
        if (nread > *nbytes)	/* Sanity check for bogus server.  */
  	{
  	  __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
  	  return EGRATUITOUS;
  	}
        memcpy (buf, data, nread);
        __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
      }
  
    *nbytes = nread;
    return 0;
  }
  