freebsd-nq/sys/i386/boot/dosboot/syslimit.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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3.1 KiB
C

/*
* Copyright (c) 1988 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: @(#)syslimits.h 7.4 (Berkeley) 2/4/91
* $Id: syslimits.h,v 1.4 1994/01/20 22:57:32 davidg Exp $
*/
#ifndef _SYS_SYSLIMITS_H_
#define _SYS_SYSLIMITS_H_ 1
#define ARG_MAX 32768 /* max bytes for an exec function */
#define CHILD_MAX 40 /* max simultaneous processes */
#define LINK_MAX 32767 /* max file link count */
#define MAX_CANON 255 /* max bytes in terminal canonical input line */
#define MAX_INPUT 255 /* max bytes in terminal input */
#define NAME_MAX 255 /* max number of bytes in a file name */
#define NGROUPS_MAX 16 /* max number of supplemental group id's */
#define OPEN_MAX 64 /* max open files per process */
#define PATH_MAX 1024 /* max number of bytes in pathname */
#define PIPE_BUF 512 /* max number of bytes for atomic pipe writes */
#define BC_BASE_MAX 99 /* max ibase/obase values allowed by bc(1) */
#define BC_DIM_MAX 2048 /* max array elements allowed by bc(1) */
#define BC_SCALE_MAX 99 /* max scale value allowed by bc(1) */
#define BC_STRING_MAX 1000 /* max const string length allowed by bc(1) */
#define EQUIV_CLASS_MAX 2 /* max weights for order keyword; see locale */
#define EXPR_NEST_MAX 32 /* max expressions nested in expr(1) */
#define LINE_MAX 2048 /* max length in bytes of an input line */
#define RE_DUP_MAX 255 /* max repeated RE's using interval notation */
#endif /* _SYS_SYSLIMITS_H_ */