mirror of
https://github.com/freebsd/freebsd-src.git
synced 2024-12-02 23:43:25 +00:00
119 lines
3.7 KiB
C
119 lines
3.7 KiB
C
/*-
|
|
* 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);
|
|
}
|