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freebsd-dev/sys/i386/boot/dosboot/imgact.h
Poul-Henning Kamp b8e4cd2bb3 This is a MS-DOS program, but is does something useful for us: 
It boots FreeBSD from a running MS-DOS system.

It's compiled using some MS-DOS tools, but there is a binary
hidden in the uuencoded file.  (Go ahead, flame me if you can come up
with a solution for the problem.  Just saying "this is bad" doesn't count!)

Rod, you were right: one would have to deal with weird interfaces to the
memory managers, and it seems that Christian found them all, and made them
work.

Thanks Christian!

Reviewed by:	phk
Submitted by:	DI. Christian Gusenbauer <cg@fimp01.fim.uni-linz.ac.at>

Christians README:
------------------

Hi Everybody!

This is version 1.5 of "fbsdboot", a program that allows you to boot a kernel
from a MS-DOS partition or a FreeBSD partition. This program runs using DOS.
It works with various memory managers (like  EMM386, 386MAX) under certain
circumstances.

First, a FreeBSD kernel is always loaded to memory starting at 0x100000. To
assure that loading the kernel *does not* overwrite memory used by memory
managers, high memory for the kernel is allocated and after loading the kernel
it's moved to 0x100000.

Second, there are many ways to switch to protected mode which is necessary to
start the kernel. Each BIOS gives you the possibility to use INT15H (AH=89H)
to do that. But some memory-managers like 386max does not allow you to use
this method.

An other way to do the switch is to use DPMI services, but they do not
guarantee, that the protected mode application is executed with privilege
level 0. Therefore this method is *not* used.

VCPI services offer another way to switch to protected mode, and VCPI servers
are built into "emm386.exe", "386max" and "qemm". That's why, this method is
implemented in fbsdboot.exe.

Fbsdboot.exe tries to switch to protected mode using VCPI services. If they're
not available INT15H is used to do the switch. If that fails, it's not possible
for this version of fbsdboot.exe to boot a kernel :-(.

You can get commandline options of fbsdboot if you start it with "-?" as option!

I don't know, if fbsdboot works with QEMM, as I don't have the possibility to
test it.

Enjoy and have fun!

Christian.
cg@fimp01.fim.uni-linz.ac.at


PS: Many thanks to Bruce Evans for his assistance!
1995-02-15 04:45:50 +00:00

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/*-
* Copyright (c) 1992, 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. 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.
*
* from: @(#)exec.h 8.1 (Berkeley) 6/11/93
* $Id: imgact_aout.h,v 1.1 1994/09/24 21:09:18 davidg Exp $
*/
#ifndef _IMGACT_AOUT_H_
#define _IMGACT_AOUT_H_
#define N_GETMAGIC(ex) \
( (ex).a_midmag & 0xffff )
#define N_GETMID(ex) \
( (N_GETMAGIC_NET(ex) == ZMAGIC) ? N_GETMID_NET(ex) : \
((ex).a_midmag >> 16) & 0x03ff )
#define N_GETFLAG(ex) \
( (N_GETMAGIC_NET(ex) == ZMAGIC) ? N_GETFLAG_NET(ex) : \
((ex).a_midmag >> 26) & 0x3f )
#define N_SETMAGIC(ex,mag,mid,flag) \
( (ex).a_midmag = (((flag) & 0x3f) <<26) | (((mid) & 0x03ff) << 16) | \
((mag) & 0xffff) )
#define N_GETMAGIC_NET(ex) \
(ntohl((ex).a_midmag) & 0xffff)
#define N_GETMID_NET(ex) \
((ntohl((ex).a_midmag) >> 16) & 0x03ff)
#define N_GETFLAG_NET(ex) \
((ntohl((ex).a_midmag) >> 26) & 0x3f)
#define N_SETMAGIC_NET(ex,mag,mid,flag) \
( (ex).a_midmag = htonl( (((flag)&0x3f)<<26) | (((mid)&0x03ff)<<16) | \
(((mag)&0xffff)) ) )
#define N_ALIGN(ex,x) \
(N_GETMAGIC(ex) == ZMAGIC || N_GETMAGIC(ex) == QMAGIC || \
N_GETMAGIC_NET(ex) == ZMAGIC || N_GETMAGIC_NET(ex) == QMAGIC ? \
((x) + __LDPGSZ - 1) & ~(__LDPGSZ - 1) : (x))
/* Valid magic number check. */
#define N_BADMAG(ex) \
(N_GETMAGIC(ex) != OMAGIC && N_GETMAGIC(ex) != NMAGIC && \
N_GETMAGIC(ex) != ZMAGIC && N_GETMAGIC(ex) != QMAGIC /*&& \
N_GETMAGIC_NET(ex) != OMAGIC && N_GETMAGIC_NET(ex) != NMAGIC && \
N_GETMAGIC_NET(ex) != ZMAGIC && N_GETMAGIC_NET(ex) != QMAGIC*/)
/* Address of the bottom of the text segment. */
#define N_TXTADDR(ex) \
((N_GETMAGIC(ex) == OMAGIC || N_GETMAGIC(ex) == NMAGIC || \
N_GETMAGIC(ex) == ZMAGIC) ? 0 : __LDPGSZ)
/* Address of the bottom of the data segment. */
#define N_DATADDR(ex) \
N_ALIGN(ex, N_TXTADDR(ex) + (ex).a_text)
/* Text segment offset. */
#define N_TXTOFF(ex) \
(N_GETMAGIC(ex) == ZMAGIC ? __LDPGSZ : (N_GETMAGIC(ex) == QMAGIC /*|| \
N_GETMAGIC_NET(ex) == ZMAGIC*/) ? 0 : sizeof(struct exec))
/* Data segment offset. */
#define N_DATOFF(ex) \
N_ALIGN(ex, N_TXTOFF(ex) + (ex).a_text)
/* Relocation table offset. */
#define N_RELOFF(ex) \
N_ALIGN(ex, N_DATOFF(ex) + (ex).a_data)
/* Symbol table offset. */
#define N_SYMOFF(ex) \
(N_RELOFF(ex) + (ex).a_trsize + (ex).a_drsize)
/* String table offset. */
#define N_STROFF(ex) (N_SYMOFF(ex) + (ex).a_syms)
/*
* Header prepended to each a.out file.
* only manipulate the a_midmag field via the
* N_SETMAGIC/N_GET{MAGIC,MID,FLAG} macros in a.out.h
*/
struct exec {
unsigned long a_midmag; /* htonl(flags<<26 | mid<<16 | magic) */
unsigned long a_text; /* text segment size */
unsigned long a_data; /* initialized data size */
unsigned long a_bss; /* uninitialized data size */
unsigned long a_syms; /* symbol table size */
unsigned long a_entry; /* entry point */
unsigned long a_trsize; /* text relocation size */
unsigned long a_drsize; /* data relocation size */
};
#define a_magic a_midmag /* XXX Hack to work with current kern_execve.c */
/* a_magic */
#define OMAGIC 0407 /* old impure format */
#define NMAGIC 0410 /* read-only text */
#define ZMAGIC 0413 /* demand load format */
#define QMAGIC 0314 /* "compact" demand load format */
/* a_mid */
#define MID_ZERO 0 /* unknown - implementation dependent */
#define MID_SUN010 1 /* sun 68010/68020 binary */
#define MID_SUN020 2 /* sun 68020-only binary */
#define MID_I386 134 /* i386 BSD binary */
#define MID_SPARC 138 /* sparc */
#define MID_HP200 200 /* hp200 (68010) BSD binary */
#define MID_HP300 300 /* hp300 (68020+68881) BSD binary */
#define MID_HPUX 0x20C /* hp200/300 HP-UX binary */
#define MID_HPUX800 0x20B /* hp800 HP-UX binary */
/*
* a_flags
*/
#define EX_PIC 0x10 /* contains position independant code */
#define EX_DYNAMIC 0x20 /* contains run-time link-edit info */
#define EX_DPMASK 0x30 /* mask for the above */
#endif /* !_IMGACT_AOUT_H_ */
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