sysdeps/mach/hurd/dup2.c

   1 /* Copyright (C) 1991, 1992 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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23 #include <hurd.h>
  24
  25
  26 /* Duplicate FD to FD2, closing the old FD2 and making FD2 be
  27    open the same file as FD is.  Return FD2 or -1.  */
  28 int
  29 DEFUN(__dup2, (fd, fd2), int fd AND int fd2)
  30 {
  31   __mutex_lock (&_hurd_dtable_lock);
  32   if (fd < 0 || fd >= _hurd_dtable.size ||
  33       _hurd_dtable.d[fd].server == MACH_PORT_NULL ||
  34       fd2 < 0 || fd2 >= _hurd_dtable.size)
  35     {
  36       __mutex_unlock (&_hurd_dtable_lock);
  37       errno = EBADF;
  38       return -1;
  39     }
  40   if (_hurd_dtable.d[fd2].server != MACH_PORT_NULL)
  41     __mach_port_deallocate (__mach_task_self (), _hurd_dtable.d[fd2].server);
  42   _hurd_dtable.d[fd2] = _hurd_dtable.d[fd];
  43   __mach_port_mod_refs (__mach_task_self (), _hurd_dtable.d[fd].server,
  44                         MACH_PORT_RIGHT_SEND, 1);
  45   __mutex_unlock (&_hurd_dtable_lock);
  46
  47   return fd2;
  48 }