chown.java

/**
 * @author Denys Shcherbak
 */
public class chown
{
    /**
     * The name of this program.
     * This is the program name that is used
     * when displaying error messages.
     */
    public static String PROGRAM_NAME = "chown" ;


    /**
     * Checks if the path exists, and tries to change it's owner
     * @exception java.lang.Exception if an exception is thrown
     * by an underlying operation
     */

    public static void main( String[] args ) throws Exception
    {
        // initialize the file system simulator kernel
        Kernel.initialize() ;


        if(args.length < 2){
            Kernel.perror( PROGRAM_NAME ) ;
            Kernel.exit( 1 );
        }
        short owner = Short.parseShort(args[0]);
        for(int i = 1; i < args.length; i++) {
            String name = args[i];
            int status = 0;

            // stat the name to get information about the file or directory
            Stat stat = new Stat();
            status = Kernel.stat(name, stat);
            if(status == -1) {
                Kernel.perror(PROGRAM_NAME);
                Kernel.exit(1);
            }
            short empty = -1;
            status = Kernel.chown(name, owner, empty);
            if(status == -1) {
                System.err.println(PROGRAM_NAME + ": You don't have rights to perform this operation!");
                Kernel.exit(1);
            } else if(status == -2) {
                System.err.println(PROGRAM_NAME + ": Incorrect uid parameter '" + owner + "'");
                Kernel.exit(1);
            }
        }

        // exit with success if we process all the arguments
        Kernel.exit( 0 ) ;
    }
}