/*
 *	c h o w n . c
 *
 *	Creation Date:	03-July-1991 by trn@warper.jhuapl.edu <Tony Nardo>
 *	Last Modified:
 *
 *	Change file ownership #.  Somewhat dissimilar to UNIX in that it
 *	forces group *and* file ownership to change, but I wanted to keep
 *	this simple.
 *
 *	This software has been tested on an MVME147 OSK (Microware) system
 *	implementing OS-9 level 2.
 *
 *	No warranty expressed or implied. :-)
 */

#include <strings.h>

#define	HELP	"usage: chown group#.user# file [file2...]\n"

main( argc, argv )
register int	argc;
register char	**argv;
{
	unsigned long	owner;
	unsigned short	gid, uid;
	register int	i, error;
	register char	*dot;

	/*
	 * Must be sufficiently privileged to use chown.
	 */
	owner = getuid();
	if( owner & 0xffff0000 ) {
		printf( "No permission to use chown\n" );
		exit( 0 );
	}

	/*
	 * Too few arguments will force a HELP message.
	 */
	if( argc < 3 ) {
		printf( HELP );
		exit( 0 );
	}

	/*
	 * Lack of a "." in the "GID.UID" field will also force HELP.
	 */
	dot = index( argv[1], '.' );
	if( ! dot ) {
		printf( HELP );
		exit( 0 );
	}

	/*
	 * Extract the GID and UID.  Don't bother with sanity checks.
	 */
	*dot = 0;			/* erase period to terminate GID */
	dot++;				/* and look beyond it for UID	 */
	uid = atoi( dot );		/* get UID, GID			 */
	gid = atoi( argv[1] );
	owner = ( gid << 16 ) | uid;	/* OS9 format owner # format	 */

	/*
	 * All seems OK, go ahead and try to change ownerships!
	 */
	i = 2;
	do {
		error = chown( argv[ i ], owner );
		if( error ) {
			printf( "chown: %s: No such file or directory\n",
			   argv[ i ] );
		}
	} while( ++i < argc );

}