#include <u.h>#include <libc.h>#include <auth.h> voidusage(void){	fprint(2, "usage: auth/respond 'params' chal\n");	exits("usage");} voidmain(int argc, char **argv){	char buf[128];	int n; 	ARGBEGIN{	default:		usage();	}ARGEND 	if(argc != 2)		usage(); 	memset(buf, 0, sizeof buf);	n = auth_respond(argv[1], strlen(argv[1]), buf, sizeof buf-1, auth_getkey, "%s", argv[0]);	if(n < 0)		sysfatal("auth_respond: %r");	write(1, buf, n);	print("\n");}