DOS registry viewer/modifier

				
//**************************************
// Name: DOS registry viewer/modifier
// Description:I needed to be able to view/change registry keys from BAT files, the DOS command line, or even VB/VBScript, so I came up with this short program to do just that.
// By: Razvan Petrescu
//
// Inputs:Usage:
(1)registry /v basekey key1 key2... subkeyn
(2)registry /r basekey key1 key2... subkeyn value
//
// Returns:(1)value of subkeyn or error message
(2)value of subkeyn before it was replaced with parameter 'value' or error message
//
// Assumes:Current version only works with string (REG_SZ) keys.
//
// Side Effects:None.
//
//This code is copyrighted and has// limited warranties.Please see http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=1972&lngWId=3//for details.//**************************************

/////////////////////////////////////////////////////////////////////////
// registry.c
//
//
// DOS Registry key viewer/replacer.
// by Razvan Petrescu 07/16/01
//
// Current version only works with string keys.
//
// Returns value of key (old if /r) or error message.
//
/////////////////////////////////////////////////////////////////////////
#include "registry.h"
/////////////////////////////////////////////////////////////////////////
int main( int argc, char* argv[] )
{
	static char*	help = "Use: registry /function key1 key2... (subkey/parameter) n\
					\n\twhere /function = /v view value of subkey n \
					\n\t /r replace subkey n-1's value with parameter n \
					\n\n Only string parameters are accepted at the current time. \
					\n\n Key 1 has to be one of the following: \
					\n\t R for HKEY_CLASSES_ROOT \
					\n\t C for HKEY_CURRENT_CONFIG \
					\n\t U for HKEY_CURRENT_USER \
					\n\t M for HKEY_LOCAL_MACHINE \
					\n\t S for HKEY_USERS. \
					\n";
	static HKEY		root_keys[] = { HKEY_CLASSES_ROOT,
						HKEY_CURRENT_CONFIG,
						HKEY_CURRENT_USER,
						HKEY_LOCAL_MACHINE,
						HKEY_USERS };
	static char		root_id[] = { 'R', 'C', 'U','M', 'S' };
	static int		ELEMS = sizeof( root_id )/sizeof( root_id[0] );;
	BYTE			lpsval[SIZEOFRET];
	DWORD			cbval = SIZEOFRET;
	DWORD			tbuff = REG_SZ;
	LONG			retv;
	BOOL			bReplace;
	HKEY			hkey[MAXNOKEYS];
	int				argcounter, argcursor;
	char			szErr[300];
	if( !lpsval )
	{
		printf( "Can't alloc storage.", NULL, 0 );
		exit( 1 );
	}
	if( argc < 4 )
		err_out( help, NULL, 0 );
	if( argc > 2 + MAXNOKEYS )
		err_out( "Too many parameters.", NULL, 0 );
	if( argv[1][1] == 'r' )
		bReplace = TRUE;
	else
	{
		if( argv[1][1] != 'v' )
		{
			sprintf( szErr, "Unknown function %s. Type registry for help.",
				argv[1] );
			err_out( szErr, NULL, 0 );
		}
		else
			bReplace = FALSE;
	}
	for( argcounter = 0; argcounter < ELEMS; argcounter++ )
		if( argv[2][0] == root_id[ argcounter ] )
			break;
	if( argcounter == ELEMS )
	{
		sprintf( szErr, "Wrong root key %s.", argv[2] );
		err_out( szErr, NULL, 0 );
	}
	hkey[ 0 ] = root_keys[ argcounter ];
	for( argcursor = 1;
		argcursor < argc - 3 - bReplace;
		argcursor ++ )
	{
		retv = RegOpenKeyEx(
			hkey[argcursor - 1],
			argv[argcursor + 2],
			(DWORD)0,
			KEY_ALL_ACCESS,
			&hkey[argcursor]
			);
		if( retv != ERROR_SUCCESS )
		{
			sprintf( szErr, "Failed to open key %s.",
				argv[argcursor + 2]);
			err_out( szErr, hkey, argcursor );
		}
	}
	retv = RegQueryValueEx(
		hkey[argcursor - 1],
		argv[argcursor + 2],
		NULL,
		&tbuff,
		lpsval,
		&cbval );
	if( retv != ERROR_SUCCESS )
	{
		sprintf( szErr, "Failed to read subkey %s.",
			argv[argcursor + 2]);
		err_out( szErr, hkey, argcursor );
	}
	if( bReplace ){
		retv = RegSetValueEx(
			hkey[argcursor - 1],
			argv[argcursor + 2],
			(DWORD)0,
			tbuff,
			(PBYTE)argv[argcursor + 3],
			strlen( argv[argcursor + 3]) + 1);
		if( retv != ERROR_SUCCESS )
		{
			sprintf( szErr, "Failed to set subkey %s to value %s.",
				argv[argcursor + 2],
				argv[argcursor + 3]);
			err_out( szErr, hkey, argcursor );
		}
	}
	printf( "%s", (char*)lpsval );
	close_keys( hkey, argc - 2 );
	return 0;
}
/////////////////////////////////////////////////////////////////////////
static void err_out( char* szErrMsg, PHKEY hkeyarray, int howmany )
{
	_ASSERTE( szErrMsg );
	printf( "\n%s", szErrMsg );
	close_keys( hkeyarray, howmany );
	exit( 1 );
}
/////////////////////////////////////////////////////////////////////////
static void close_keys( PHKEY hkeyarray, int howmany )
{
	_ASSERTE ( hkeyarray );
	while( howmany )
		RegCloseKey( hkeyarray[howmany - 1] ), howmany--;
	return;
}
/////////////////////////////////////////////////////////////////////////