hurd/getdport.c

   1 /* Copyright (C) 1991-2017 Free Software Foundation, Inc.
   2
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  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 static file_t (*_default_hurd_getdport_fn) (int fd) = 0;
  24 weak_alias (_default_hurd_getdport_fn, _hurd_getdport_fn)
  25
  26 file_t
  27 __getdport (int fd)
  28 {
  29   if (_hurd_getdport_fn)
  30     /* dtable.c has defined the function to fetch a port from the real file
  31        descriptor table.  */
  32     return (*_hurd_getdport_fn) (fd);
  33
  34   /* getdport is the only use of file descriptors,
  35      so we don't bother allocating a real table.  */
  36
  37   if (_hurd_init_dtable == NULL)
  38     {
  39       /* Never had a descriptor table.  */
  40       errno = EBADF;
  41       return MACH_PORT_NULL;
  42     }
  43
  44   if (fd < 0 || (unsigned int) fd > _hurd_init_dtablesize ||
  45       _hurd_init_dtable[fd] == MACH_PORT_NULL)
  46     {
  47       errno = EBADF;
  48       return MACH_PORT_NULL;
  49     }
  50   else
  51     {
  52       __mach_port_mod_refs (__mach_task_self (), _hurd_init_dtable[fd],
  53                             MACH_PORT_RIGHT_SEND, 1);
  54       return _hurd_init_dtable[fd];
  55     }
  56 }
  57
  58 weak_alias (__getdport, getdport)