Stuff

IORegistryEntry * IORegistryEntry::fromPath(
                        char * 		path,
                        const IORegistryPlane * plane,
                        char *			opath,
			int * 			length,
                        IORegistryEntry * 	fromEntry )
{
    IORegistryEntry *	where = 0;
    IORegistryEntry *	aliasEntry = 0;
    IORegistryEntry *	next;
    char *	alias;
    char *	end;
    char *  path; 
 		int			len = 0;
    int			len2;
    char		c;
    char		temp[ kIOMaxPlaneName + 1 ];
		char * pathfinder;
		
		pathfinder  = path;


    if( 0 == path)
		return( 0 );

    if( 0 == plane) {
	// get plane name
		if( (path[13] == 0x2F) && (path[14] == 0x65) && (path[15] == 0x66) && (path[16] == 0x69) ) {			
			pathfinder[14] = 0x72;
			pathfinder[15] = 0x6F;
			pathfinder[16] = 0x6D;
        }
		end = strchr( pathfinder, ':' );
	if( end && ((end - pathfinder) < kIOMaxPlaneName)) {
	    strncpy( temp, pathfinder, end - pathfinder );
	    temp[ end - pathfinder ] = 0;
            plane = getPlane( temp );
	    pathfinder = end + 1;
	}
    }
    if( 0 == plane)
	return( 0 );

    // check for alias
    end = pathfinder;
    if( (alias = dealiasPath( &end, plane))) {
        if(length)
            len = *length;
        aliasEntry = IORegistryEntry::fromPath( alias, plane,
                                    opath, &len, fromEntry );
        where = aliasEntry;
        if( where)
            pathfinder = end;
        else
            len = 0;
    }

    RLOCK;

    do {
        if( 0 == where) {
            if( (0 == fromEntry) && (*pathfinder++ == '/'))
                fromEntry = gRegistryRoot->getChildEntry( plane );
            where = fromEntry;
            if( 0 == where)
                break;
        } else {
            c = *pathfinder++;
            if( c != '/') {
                if( c && (c != ':'))	// check valid terminator
                    where = 0;
                break;
            }
        }
        next = where->getChildFromComponent( &pathfinder, plane );
        if( next)
            where = next;
    } while( next );

    if( where) {
	// check residual path
	if( where != fromEntry)
            pathfinder--;

	if( opath && length) {
            // copy out residual path
	    len2 = len + strlen( pathfinder );
	    if( len2 < *length)
                strcpy( opath + len, pathfinder );
	    *length = len2;

	} else if( pathfinder[0])
	    // no residual path => must be no tail for success
            where = 0;
    }

    if( where)
	where->retain();
    if( aliasEntry)
        aliasEntry->release();

    UNLOCK;

    return( where );
}