Path: utzoo!attcan!uunet!lll-winken!ames!oliveb!stratus!gbs
From: gbs@stratus.UUCP (George B. Smith)
Newsgroups: comp.sys.ibm.pc
Subject: Re: How could I force a CTRL-ALT-DEL from a program?
Message-ID: <1524@stratus.UUCP>
Date: 24 Jan 89 07:00:49 GMT
References: <4567@bunker.UUCP> <86397@sun.uucp>
Reply-To: gbs@stratus.UUCP (George B. Smith)
Organization: Stratus Computer, Inc. Western Development Center
Lines: 59

In article <86397@sun.uucp> jborza%burgundy@Sun.COM (Jim_Borza) writes:
>In article <4567@bunker.UUCP>, rha@bunker.UUCP (Robert H. Averack) writes:
>>      I am investigating how one can remotely cause a PC to reboot.  Getting
>> the stimulus to the PC is clearly not the problem.  The problem is getting
>> the software which recognizes the stimulus to issue a CTRL-ALT-DEL to MSDOS,
>> resulting in the reset and reboot.
>> 
>
>You can reboot a PC with the following code.
>Assemble with MASM and convert to .COM via EXE2BIN.

... assembly lanuage program deleted

>Jim Borza - Sun Microsystems

Here is a Turbo C program to do the same thing:

/*
** boot.c
**
** This small program will reboot an IBM PC or clone.  If there are no
** command line arguments or there is a single argument of "warm", then
** a warm boot is performed.  If there is a single argument of "cold",
** then a cold boot is performed.
**
** The mechanics of this feat result from the following convention
** supported by virtually every BIOS:
**
**	If you jump into the BIOS with location 0040:0072H set to the
**	magic quatity of 1234H, and jump to the entry point of the BIOS
**	at location FFFF:0000h, the system will perform a warm boot
**	(i.e., no power-on self-test, etc.).  Putting anything else in
**	that memory location will force a cold boot.
*/

#include <stdio.h>

main(argc, argv)
int argc;
char *argv[];
{
	void (far *bye) ();
	int far *pt;

	pt = (int far *) 0x00000472L;		/* location in memory for */
						/* boot magic number */
	if (argc < 2)
		*pt = 0x1234;			/* warm boot magic number */
	else if (argc == 2 && !strcmp("warm", argv[1]))
		*pt = 0x1234;			/* warm boot magic number */
	else if (argc == 2 && !strcmp("cold", argv[1]))
		*pt = 0x0000;			/* cold boot magic number */
	else {
		fprintf(stderr, "Usage: boot [warm | cold]\n");
		exit(1);
	}
	bye = (void far *) 0x0ffff0000L;	/* boot code in ROM BIOS */
	(*bye)();
}