/*- * 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 rcsid[] = "$OpenBSD: makebuf.c,v 1.2 1996/08/19 08:32:54 tholo Exp $";#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);}