1/* Copyright (C) 1993, 1997 Free Software Foundation, Inc.
2   This file is part of the GNU IO Library.
3
4   This library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU General Public License as
6   published by the Free Software Foundation; either version 2, or (at
7   your option) any later version.
8
9   This library is distributed in the hope that it will be useful, but
10   WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this library; see the file COPYING.  If not, write to
16   the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
17   MA 02111-1307, USA.
18
19   As a special exception, if you link this library with files
20   compiled with a GNU compiler to produce an executable, this does
21   not cause the resulting executable to be covered by the GNU General
22   Public License.  This exception does not however invalidate any
23   other reasons why the executable file might be covered by the GNU
24   General Public License.  */
25
26/*
27 * Copyright (c) 1990 The Regents of the University of California.
28 * All rights reserved.
29 *
30 * Redistribution and use in source and binary forms are permitted
31 * provided that the above copyright notice and this paragraph are
32 * duplicated in all such forms and that any documentation,
33 * advertising materials, and other materials related to such
34 * distribution and use acknowledge that the software was developed
35 * by the University of California, Berkeley.  The name of the
36 * University may not be used to endorse or promote products derived
37 * from this software without specific prior written permission.
38 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
39 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
40 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
41 */
42
43/* Modified for GNU iostream by Per Bothner 1991, 1992. */
44
45#include "libioP.h"
46#include <sys/types.h>
47#include <sys/stat.h>
48#ifdef __STDC__
49#include <stdlib.h>
50#include <unistd.h>
51#endif
52
53#ifdef _LIBC
54# undef isatty
55# define isatty(Fd) __isatty (Fd)
56#endif
57
58/*
59 * Allocate a file buffer, or switch to unbuffered I/O.
60 * Per the ANSI C standard, ALL tty devices default to line buffered.
61 *
62 * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
63 * optimisation) right after the _fstat() that finds the buffer size.
64 */
65
66int
67_IO_file_doallocate (fp)
68     _IO_FILE *fp;
69{
70  _IO_size_t size;
71  int couldbetty;
72  char *p;
73  struct stat st;
74
75#if !defined(_LIBC) && !defined(__linux__)
76  /* If _IO_cleanup_registration_needed is non-zero, we should call the
77     function it points to.  This is to make sure _IO_cleanup gets called
78     on exit.  We call it from _IO_file_doallocate, since that is likely
79     to get called by any program that does buffered I/O. */
80  if (_IO_cleanup_registration_needed)
81    (*_IO_cleanup_registration_needed) ();
82#endif
83
84  if (fp->_fileno < 0 || _IO_SYSSTAT (fp, &st) < 0)
85    {
86      couldbetty = 0;
87      size = _IO_BUFSIZ;
88#if 0
89      /* do not try to optimise fseek() */
90      fp->_flags |= __SNPT;
91#endif
92    }
93  else
94    {
95      couldbetty = S_ISCHR (st.st_mode);
96#if _IO_HAVE_ST_BLKSIZE
97      size = st.st_blksize <= 0 ? _IO_BUFSIZ : st.st_blksize;
98#else
99      size = _IO_BUFSIZ;
100#endif
101    }
102  ALLOC_BUF (p, size, EOF);
103  _IO_setb (fp, p, p + size, 1);
104  if (couldbetty && isatty (fp->_fileno))
105    fp->_flags |= _IO_LINE_BUF;
106  return 1;
107}
108