port/stdio/setvbuf.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1988 AT&T */
/*    All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "lint.h"
#include "file64.h"
#include "mtlib.h"
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <thread.h>
#include <synch.h>
#include "stdiom.h"

int
setvbuf(FILE *iop, char *abuf, int type, size_t size)
{

    Uchar   *buf = (Uchar *)abuf;
    Uchar *temp;
    int sflag = iop->_flag & _IOMYBUF;
    rmutex_t *lk;
    int fd = GET_FD(iop);

    FLOCKFILE(lk, iop);
    iop->_flag &= ~(_IOMYBUF | _IONBF | _IOLBF);
    switch (type) {
    /* note that the flags are the same as the possible values for type */
    case _IONBF:
        iop->_flag |= _IONBF;    /* file is unbuffered */
#ifndef _STDIO_ALLOCATE
        if (fd < 2) {
            /* use special buffer for std{in,out} */
            buf = (fd == 0) ? _sibuf : _sobuf;
            size = BUFSIZ;
        } else /* needed for ifdef */
#endif
        if (fd < _NFILE) {
            buf = _smbuf[fd];
            size = _SMBFSZ - PUSHBACK;
        } else
            if ((buf = malloc(_SMBFSZ * sizeof (Uchar))) != NULL) {
                iop->_flag |= _IOMYBUF;
                size = _SMBFSZ - PUSHBACK;
            } else {
                FUNLOCKFILE(lk);
                return (EOF);
            }
        break;
    case _IOLBF:
    case _IOFBF:
        iop->_flag |= type; /* buffer file */
        /*
         * need at least an 8 character buffer for
         * out_of_sync concerns.
         */
        if (size <= _SMBFSZ) {
            size = BUFSIZ;
            buf = NULL;
        }
        if (buf == NULL) {
            if ((buf = malloc(sizeof (Uchar) *
                (size + _SMBFSZ))) != NULL)
                iop->_flag |= _IOMYBUF;
            else {
                FUNLOCKFILE(lk);
                return (EOF);
            }
        }
        else
            size -= _SMBFSZ;
        break;
    default:
        FUNLOCKFILE(lk);
        return (EOF);
    }
    if (iop->_base != NULL && sflag)
        free((char *)iop->_base - PUSHBACK);
    temp = buf + PUSHBACK;
    iop->_base = temp;
    _setbufend(iop, temp + size);
    iop->_ptr = temp;
    iop->_cnt = 0;
    FUNLOCKFILE(lk);
    return (0);
}