Go to most recent revision |
Blame |
Compare with Previous |
Last modification |
View Log
| RSS feed
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 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
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid
[] = "@(#)makebuf.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include "local.h"
/*
* 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.
*/
void
__smakebuf
(fp
)
register FILE
*fp
;
{
register void *p
;
register int flags
;
size_t size
;
int couldbetty
;
if (fp
->_flags
& __SNBF
) {
fp
->_bf._base
= fp
->_p
= fp
->_nbuf
;
fp
->_bf._size
= 1;
return;
}
flags
= __swhatbuf
(fp
, &size
, &couldbetty
);
if ((p
= malloc(size
)) == NULL
) {
fp
->_flags
|= __SNBF
;
fp
->_bf._base
= fp
->_p
= fp
->_nbuf
;
fp
->_bf._size
= 1;
return;
}
__cleanup
= _cleanup
;
flags
|= __SMBF
;
fp
->_bf._base
= fp
->_p
= p
;
fp
->_bf._size
= size
;
if (couldbetty
&& isatty
(fp
->_file
))
flags
|= __SLBF
;
fp
->_flags
|= flags
;
}
/*
* Internal routine to determine `proper' buffering for a file.
*/
int
__swhatbuf
(fp
, bufsize
, couldbetty
)
register FILE
*fp
;
size_t *bufsize
;
int *couldbetty
;
{
struct stat st
;
if (fp
->_file
< 0 || fstat
(fp
->_file
, &st
) < 0) {
*couldbetty
= 0;
*bufsize
= BUFSIZ
;
return (__SNPT
);
}
/* could be a tty iff it is a character device */
*couldbetty
= (st.
st_mode & S_IFMT
) == S_IFCHR
;
if (st.
st_blksize <= 0) {
*bufsize
= BUFSIZ
;
return (__SNPT
);
}
/*
* 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
?
__SOPT
: __SNPT
);
}