#include <u.h>#include <libc.h>#include <auth.h> voidusage(void){	fprint(2, "usage: auth/challenge 'params'\n");	exits("usage");} voidmain(int argc, char **argv){	char buf[128], bufu[128];	int afd, n;	AuthInfo *ai;	AuthRpc *rpc;	Chalstate *c; 	ARGBEGIN{	default:		usage();	}ARGEND 	if(argc != 1)		usage(); 	if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0)		sysfatal("open /mnt/factotum/rpc: %r"); 	rpc = auth_allocrpc(afd);	if(rpc == nil)		sysfatal("auth_allocrpc: %r"); 	if((c = auth_challenge("%s", argv[0])) == nil)		sysfatal("auth_challenge: %r"); 	print("challenge: %s\n", c->chal);	print("user:");	n = read(0, bufu, sizeof bufu);	if(n > 0){		bufu[n-1] = '\0';		c->user = bufu;	} 	print("response: ");	n = read(0, buf, sizeof buf);	if(n < 0)		sysfatal("read: %r");	if(n == 0)		exits(nil);	c->nresp = n-1;	c->resp = buf;	if((ai = auth_response(c)) == nil)		sysfatal("auth_response: %r"); 	print("%s %s\n", ai->cuid, ai->suid);}