sysdeps/mach/hurd/defs.c

   1 /* Definitions of global stdio data structures.
   2
   3 Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   4 This file is part of the GNU C Library.
   5
   6 The GNU C Library is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public License as
   8 published by the Free Software Foundation; either version 2 of the
   9 License, or (at your option) any later version.
  10
  11 The GNU C Library is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with the GNU C Library; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  19 Cambridge, MA 02139, USA.  */
  20
  21 #include <ansidecl.h>
  22 #include <stdio.h>
  23 #include <hurd/fd.h>
  24 #include <unistd.h>
  25
  26 FILE *stdin, *stdout, *stderr;
  27
  28 /* Pointer to the first stream in the list.  */
  29 FILE *__stdio_head = NULL;
  30
  31 static void
  32 init_stdio (void)
  33 {
  34   inline void init (FILE **streamptr, int fd)
  35     {
  36       /* We want to use the existing FILE object if one has been allocated.
  37          (This will only be the case if our image came from something like
  38          Emacs's unexec, where we were called in the first run.)  */
  39       FILE *s = *streamptr ?: __newstream ();
  40       struct hurd_fd *d = _hurd_fd_get (fd);
  41       if (d == NULL)
  42         {
  43           /* There is no file descriptor allocated.  We want the standard
  44              streams to always refer to their standard file descriptors, even
  45              if those descriptors are not set up until later.  So allocate
  46              the descriptor structure with no ports and store it in the
  47              stream.  Operations will fail until ports are installed in the
  48              file descriptor.  */
  49           if (d = _hurd_alloc_fd (NULL, fd))
  50             __spin_unlock (&d->port.lock);
  51         }
  52       if (s)
  53         s->__cookie = d;
  54       *streamptr = s;
  55     }
  56 #define S(NAME, FD, MODE) \
  57   init (&NAME, FD); if (NAME) NAME->__mode.__##MODE = 1;
  58
  59   S (stdin, STDIN_FILENO, read);
  60   S (stdout, STDOUT_FILENO, write);
  61   S (stderr, STDERR_FILENO, write);
  62
  63 #undef S
  64
  65   if (stderr)
  66     stderr->__userbuf = 1;      /* stderr is always unbuffered.  */
  67
  68   (void) &init_stdio;           /* Avoid "defined but not used" warning.  */
  69 }
  70 text_set_element (_hurd_fd_subinit, init_stdio);
  71 \f
  72 /* This function MUST be in this file!
  73    This is because we want _cleanup to go into the __libc_atexit set
  74    when any stdio code is used (and to use any stdio code, one must reference
  75    something defined in this file), and since only local symbols can be made
  76    set elements, having the set element stab entry here and _cleanup elsewhere
  77    loses; and having them both elsewhere loses because there is no reference
  78    to cause _cleanup to be linked in.  */
  79
  80 void
  81 DEFUN_VOID(_cleanup)
  82 {
  83   (void) fclose ((FILE *) NULL);
  84 }
  85 text_set_element (__libc_atexit, _cleanup);