hurd/getdport.c

   1 /* Copyright (C) 1991, 1992, 1994, 1995, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <hurd.h>
  20
  21 /* This is initialized in dtable.c when that gets linked in.
  22    If dtable.c is not linked in, it will be zero.  */
  23 file_t (*_hurd_getdport_fn) (int fd);
  24
  25 file_t
  26 __getdport (int fd)
  27 {
  28   if (_hurd_getdport_fn)
  29     /* dtable.c has defined the function to fetch a port from the real file
  30        descriptor table.  */
  31     return (*_hurd_getdport_fn) (fd);
  32
  33   /* getdport is the only use of file descriptors,
  34      so we don't bother allocating a real table.  */
  35
  36   if (_hurd_init_dtable == NULL)
  37     /* Never had a descriptor table.  */
  38     return EBADF;
  39
  40   if (fd < 0 || (unsigned int) fd > _hurd_init_dtablesize ||
  41       _hurd_init_dtable[fd] == MACH_PORT_NULL)
  42     {
  43       errno = EBADF;
  44       return MACH_PORT_NULL;
  45     }
  46   else
  47     {
  48       __mach_port_mod_refs (__mach_task_self (), _hurd_init_dtable[fd],
  49                             MACH_PORT_RIGHT_SEND, 1);
  50       return _hurd_init_dtable[fd];
  51     }
  52 }
  53
  54 weak_alias (__getdport, getdport)