* Copyright (c) 1990 The Regents of the University of California.
* This code is derived from software contributed to Berkeley by
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)makebuf.c 5.3 (Berkeley) 5/6/93";
#endif /* LIBC_SCCS and not lint */
* Allocate a file buffer, or switch to unbuffered I/O.
* Per the ANSI C standard, ALL tty devices default to line buffered.
* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
* optimisation) right after the fstat() that finds the buffer size.
if (fp
->_flags
& __SNBF
) {
fp
->_bf
._base
= fp
->_p
= fp
->_nbuf
;
flags
= __swhatbuf(fp
, &size
, &couldbetty
);
if ((p
= malloc(size
)) == NULL
) {
fp
->_bf
._base
= fp
->_p
= fp
->_nbuf
;
fp
->_bf
._base
= fp
->_p
= p
;
if (couldbetty
&& isatty(fp
->_file
))
* Internal routine to determine `proper' buffering for a file.
__swhatbuf(fp
, bufsize
, couldbetty
)
if (fp
->_file
< 0 || fstat(fp
->_file
, &st
) < 0) {
/* could be a tty iff it is a character device */
*couldbetty
= (st
.st_mode
& S_IFMT
) == S_IFCHR
;
if (st
.st_blksize
<= 0) {
* Optimise fseek() only if it is a regular file. (The test for
* __sseek is mainly paranoia.) It is safe to set _blksize
* unconditionally; it will only be used if __SOPT is also set.
*bufsize
= st
.st_blksize
;
fp
->_blksize
= st
.st_blksize
;
return ((st
.st_mode
& S_IFMT
) == S_IFREG
&& fp
->_seek
== __sseek
?