usr/src/sys/i386/stand/bootxx.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * 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.
 *
 *      @(#)bootxx.c    5.2 (Berkeley) 4/28/91
 */

#include "param.h"
#include <a.out.h>
#include "saio.h"
#include "reboot.h"
#include "disklabel.h"

char *bootprog = "/boot";
extern int opendev, bootdev, cyloffset;
extern struct disklabel disklabel;

/*
 * Boot program... loads /boot out of filesystem indicated by arguements.
 * We assume an autoboot unless we detect a misconfiguration.
 */

main(dev, unit, off)
{
        register struct disklabel *lp;
        register int io, partition, howto;


        /* are we a disk, if so look at disklabel and do things */
        lp = &disklabel;
        if (lp->d_magic == DISKMAGIC) {
            /*
             * Synthesize bootdev from dev, unit, type and partition
             * information from the block 0 bootstrap.
             * It's dirty work, but someone's got to do it.
             * This will be used by the filesystem primatives, and
             * drivers. Ultimately, opendev will be created corresponding
             * to which drive to pass to top level bootstrap.
             */
            for (io = 0; io < 8; io++)
#ifdef notyetSCSI
                if (lp->d_type == DTYPE_SCSI) {
                        if (lp->d_partitions[io].p_offset == off)
                                break;
                } else
#endif
                if (lp->d_partitions[io].p_offset == off*lp->d_secpercyl)
                        break;

            if (io == 8) goto screwed;
            cyloffset = off;
        } else {
screwed:
                /* probably a bad or non-existant disklabel */
                io = 0 ;
                howto |= RB_SINGLE|RB_ASKNAME ;
        }

        /* construct bootdev */
        /* currently, PC has no way of booting off alternate controllers */
        bootdev = MAKEBOOTDEV(/*i_dev*/ dev, /*i_adapt*/0, /*i_ctlr*/0,
            unit, /*i_part*/io);

        printf("loading %s\n", bootprog);
        io = open(bootprog, 0);
        if (io >= 0)
                copyunix(io, howto);
        _stop("boot failed\n");
}

/*ARGSUSED*/
copyunix(io, howto)
        register io;
{
        struct exec x;
        register int i;
        char *addr;

        i = read(io, (char *)&x, sizeof x);
        if (i != sizeof x ||
            (x.a_magic != 0407 && x.a_magic != 0413 && x.a_magic != 0410))
                _stop("Bad format\n");

        if ((x.a_magic == 0413 || x.a_magic == 0410) &&
            lseek(io, 0x400, 0) == -1)
                goto shread;

        if (read(io, (char *)0, x.a_text) != x.a_text)
                goto shread;

        addr = (char *)x.a_text;
        if (x.a_magic == 0413 || x.a_magic == 0410)
                while ((int)addr & CLOFSET)
                        *addr++ = 0;

        if (read(io, addr, x.a_data) != x.a_data)
                goto shread;

        addr += x.a_data;
        for (i = 0; i < x.a_bss; i++)
                *addr++ = 0;

        (*((int (*)()) x.a_entry))(howto, opendev, cyloffset);
        return;
shread:
        _stop("Short read\n");
}