1  /* Copyright (C) 1991-2023 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     <https://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      /* Never had a descriptor table.  */
      39      return __hurd_fail (EBADF), MACH_PORT_NULL;
      40  
      41    if (fd < 0 || (unsigned int) fd > _hurd_init_dtablesize
      42        || _hurd_init_dtable[fd] == MACH_PORT_NULL)
      43      return __hurd_fail (EBADF), MACH_PORT_NULL;
      44    else
      45      {
      46        __mach_port_mod_refs (__mach_task_self (), _hurd_init_dtable[fd],
      47  			    MACH_PORT_RIGHT_SEND, 1);
      48        return _hurd_init_dtable[fd];
      49      }
      50  }
      51  
      52  weak_alias (__getdport, getdport)