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Initial revision

/*	$OpenBSD: exec_aout.c,v 1.2 2006/05/20 22:40:46 miod Exp $	*/

/*-
 * Copyright (c) 1982, 1986, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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.
 *
 * 	@(#)boot.c	8.1 (Berkeley) 6/10/93
 */

#include <sys/param.h>
#include <sys/reboot.h>
#include <machine/prom.h>
#include <a.out.h>

#include "stand.h"
#include "libsa.h"

#define	SYM_MAGIC	0x6274ef2e

/*ARGSUSED*/
void
exec_aout(char *file, const char *args, int bootdev, int bootunit, int bootpart)
{
	char *loadaddr;
	int io;
	struct exec x;
	int cc, magic;
	void (*entry)();
	char *cp;
	int *ip;

	io = open(file, 0);
	if (io < 0)
		return;

	/*
	 * Read in the exec header, and validate it.
	 */
	if (read(io, (char *)&x, sizeof(x)) != sizeof(x))
		goto shread;

	if (N_BADMAG(x)) {
		errno = EFTYPE;
		goto closeout;
	}

	/*
	 * note: on the mvme ports, the kernel is linked in such a way that 
	 * its entry point is the first item in .text, and thus a_entry can 
	 * be used to determine both the load address and the entry point.
	 * (also note that we make use of the fact that the kernel will live
	 *  in a VA == PA range of memory ... otherwise we would take 
	 *  loadaddr as a parameter and let the kernel relocate itself!)
	 *
	 * note that ZMAGIC files included the a.out header in the text area
	 * so we must mask that off (has no effect on the other formats)
	 */
	loadaddr = (void *)(x.a_entry & ~sizeof(x));

	cp = loadaddr;
	magic = N_GETMAGIC(x);
	if (magic == ZMAGIC)
		cp += sizeof(x);
	entry = (void (*)())cp;

	/*
	 * Read in the text segment.
	 */
	printf("%d", x.a_text);
	cc = x.a_text;
	if (magic == ZMAGIC)
		cc = cc - sizeof(x); /* a.out header part of text in zmagic */
	if (read(io, cp, cc) != cc)
		goto shread;
	cp += cc;

	/*
	 * NMAGIC may have a gap between text and data.
	 */
	if (magic == NMAGIC) {
		register int mask = N_PAGSIZ(x) - 1;
		while ((int)cp & mask)
			*cp++ = 0;
	}

	/*
	 * Read in the data segment.
	 */
	printf("+%d", x.a_data);
	if (read(io, cp, x.a_data) != x.a_data)
		goto shread;
	cp += x.a_data;

	/*
	 * Zero out the BSS section.
	 */
	printf("+%d", x.a_bss);
	cc = x.a_bss;
	while ((int)cp & 3) {
		*cp++ = 0;
		--cc;
	}
	ip = (int *)cp;
	cp += cc;
	while ((char *)ip < cp)
		*ip++ = 0;

	/*
	 * Read in the symbol table and strings.
	 * (Always set the symtab size word.)
	 */
	*ip++ = x.a_syms;
	cp = (char *) ip;

	if (x.a_syms > 0) {
		/* Symbol table and string table length word. */
		cc = x.a_syms;
		printf("+[%d", cc);
		cc += sizeof(int);	/* strtab length too */
		if (read(io, cp, cc) != cc)
			goto shread;
		cp += x.a_syms;
		ip = (int *)cp;		/* points to strtab length */
		cp += sizeof(int);

		/* String table.  Length word includes itself. */
		cc = *ip;
		printf("+%d]", cc);
		cc -= sizeof(int);
		if (cc <= 0)
			goto shread;
		if (read(io, cp, cc) != cc)
			goto shread;
		cp += cc;
	}
	printf("=0x%lx\n", cp - loadaddr);
	close(io);

	(*entry)(args, bootdev, bootunit, bootpart, SYM_MAGIC, cp);

	printf("exec: kernel returned!\n");
	return;

shread:
	printf("exec: short read\n");
	errno = EIO;
closeout:
	close(io);
	return;
}