libio/filedoalloc.c

   1 /* Copyright (C) 1993, 1997, 2001, 2002 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 /*
  29    Copyright (C) 1990 The Regents of the University of California.
  30    All rights reserved.
  31
  32    Redistribution and use in source and binary forms, with or without
  33    modification, are permitted provided that the following conditions
  34    are met:
  35
  36    1. Redistributions of source code must retain the above copyright
  37       notice, this list of conditions and the following disclaimer.
  38    2. Redistributions in binary form must reproduce the above copyright
  39       notice, this list of conditions and the following disclaimer in the
  40       documentation and/or other materials provided with the distribution.
  41    4. Neither the name of the University nor the names of its contributors
  42       may be used to endorse or promote products derived from this software
  43       without specific prior written permission.
  44
  45    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55    SUCH DAMAGE.*/
  56
  57 /* Modified for GNU iostream by Per Bothner 1991, 1992. */
  58
  59 #ifndef _POSIX_SOURCE
  60 # define _POSIX_SOURCE
  61 #endif
  62 #include "libioP.h"
  63 #include <sys/types.h>
  64 #include <sys/stat.h>
  65 #ifdef __STDC__
  66 #include <stdlib.h>
  67 #include <unistd.h>
  68 #endif
  69
  70 #ifdef _LIBC
  71 # undef isatty
  72 # define isatty(Fd) __isatty (Fd)
  73
  74 # include <device-nrs.h>
  75 #endif
  76
  77 /*
  78  * Allocate a file buffer, or switch to unbuffered I/O.
  79  * Per the ANSI C standard, ALL tty devices default to line buffered.
  80  *
  81  * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
  82  * optimisation) right after the _fstat() that finds the buffer size.
  83  */
  84
  85 int
  86 _IO_file_doallocate (fp)
  87      _IO_FILE *fp;
  88 {
  89   _IO_size_t size;
  90   char *p;
  91   struct _G_stat64 st;
  92
  93 #ifndef _LIBC
  94   /* If _IO_cleanup_registration_needed is non-zero, we should call the
  95      function it points to.  This is to make sure _IO_cleanup gets called
  96      on exit.  We call it from _IO_file_doallocate, since that is likely
  97      to get called by any program that does buffered I/O. */
  98   if (__builtin_expect (_IO_cleanup_registration_needed != NULL, 0))
  99     (*_IO_cleanup_registration_needed) ();
 100 #endif
 101
 102   size = _IO_BUFSIZ;
 103   if (fp->_fileno >= 0 && __builtin_expect (_IO_SYSSTAT (fp, &st), 0) >= 0)
 104     {
 105       if (S_ISCHR (st.st_mode))
 106         {
 107           /* Possibly a tty.  */
 108           if (
 109 #ifdef DEV_TTY_P
 110               DEV_TTY_P (&st) ||
 111 #endif
 112               isatty (fp->_fileno))
 113             fp->_flags |= _IO_LINE_BUF;
 114         }
 115 #if _IO_HAVE_ST_BLKSIZE
 116       if (st.st_blksize > 0)
 117         size = st.st_blksize;
 118 #endif
 119     }
 120   ALLOC_BUF (p, size, EOF);
 121   INTUSE(_IO_setb) (fp, p, p + size, 1);
 122   return 1;
 123 }
 124 INTDEF(_IO_file_doallocate)