GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/stdio/makebuf.c Lines: 23 32 71.9 %
Date: 2017-11-13 Branches: 11 16 68.8 %

Line Branch Exec Source
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/*	$OpenBSD: makebuf.c,v 1.9 2015/01/13 07:18:21 guenther Exp $ */
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/*-
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 * Copyright (c) 1990, 1993
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 *	The Regents of the University of California.  All rights reserved.
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 *
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 * This code is derived from software contributed to Berkeley by
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 * Chris Torek.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "local.h"
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/*
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 * Allocate a file buffer, or switch to unbuffered I/O.
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 * Per the ANSI C standard, ALL tty devices default to line buffered.
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 *
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 * As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
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 * optimisation) right after the fstat() that finds the buffer size.
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 */
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void
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__smakebuf(FILE *fp)
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{
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	void *p;
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	int flags;
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1000
	size_t size;
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	int couldbetty;
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	if (fp->_flags & __SNBF) {
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9
		fp->_bf._base = fp->_p = fp->_nbuf;
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		fp->_bf._size = 1;
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		return;
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	}
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	flags = __swhatbuf(fp, &size, &couldbetty);
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	if ((p = malloc(size)) == NULL) {
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		fp->_flags |= __SNBF;
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		fp->_bf._base = fp->_p = fp->_nbuf;
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		fp->_bf._size = 1;
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		return;
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	}
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	flags |= __SMBF;
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	fp->_bf._base = fp->_p = p;
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	fp->_bf._size = size;
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	if (couldbetty && isatty(fp->_file))
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		flags |= __SLBF;
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	fp->_flags |= flags;
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}
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/*
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 * Internal routine to determine `proper' buffering for a file.
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 */
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int
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__swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)
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{
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	struct stat st;
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	if (fp->_file < 0 || fstat(fp->_file, &st) < 0) {
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		*couldbetty = 0;
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		*bufsize = BUFSIZ;
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		return (__SNPT);
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	}
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	/* could be a tty iff it is a character device */
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	*couldbetty = S_ISCHR(st.st_mode);
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	if (st.st_blksize == 0) {
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		*bufsize = BUFSIZ;
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		return (__SNPT);
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	}
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	/*
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	 * Optimise fseek() only if it is a regular file.  (The test for
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	 * __sseek is mainly paranoia.)  It is safe to set _blksize
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	 * unconditionally; it will only be used if __SOPT is also set.
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	 */
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	*bufsize = st.st_blksize;
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	fp->_blksize = st.st_blksize;
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	return ((st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
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	    __SOPT : __SNPT);
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}