Colony » Colony Scout

/*-

 * 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. 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.

 */

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include <stdio.h>

#include <stdlib.h>

#include "local.h"

/*

 * Internal routine to determine `proper' buffering for a file.

 */

static int

__swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)

{

        struct stat st;

        *bufsize = BUFSIZ;

        *couldbetty = 0;

        if (fp->_file < 0 || fstat(fp->_file, &st) < 0)

                return 0;

        /* could be a tty iff it is a character device */

        *couldbetty = S_ISCHR(st.st_mode);

        return 0;

}

/*

 * 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)

        FILE *fp;

{

        void *p;

        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;

}