#include <u.h>#include <libc.h>#include <auth.h> int	readln(char*, char*, int); voiderror(char *fmt, ...){	char buf[8192], *s; 	s = buf;	s += sprint(s, "netkey: ");	s = doprint(s, buf + sizeof(buf) / sizeof(*buf), fmt, &fmt + 1);	*s++ = '\n';	write(2, buf, s - buf);	exits(buf);} voidusage(void){	fprint(2, "usage: netkey\n");	exits("usage");} voidmain(int argc, char *argv[]){	char buf[32], pass[32], key[DESKEYLEN];	char *s;	int n; 	ARGBEGIN{	default:		usage();	}ARGEND	if(argc)		usage(); 	s = getenv("service");	if(s && strcmp(s, "cpu") == 0){		fprint(2, "netkey must not be run on the cpu server\n");		exits("boofhead");	} 	readln("Password: ", pass, sizeof pass);	passtokey(key, pass); 	for(;;){		print("challenge: ");		n = read(0, buf, sizeof buf - 1);		if(n <= 0)			exits(0);		buf[n] = '\0';		n = strtol(buf, 0, 10);		sprint(buf, "%d", n);		netcrypt(key, buf);		print("response: %s\n", buf);	}} intreadln(char *prompt, char *line, int len){	char *p;	int fd, ctl, n, nr; 	fd = open("/dev/cons", ORDWR);	if(fd < 0)		error("couldn't open cons");	ctl = open("/dev/consctl", OWRITE);	if(ctl < 0)		error("couldn't set raw mode");	write(ctl, "rawon", 5);	fprint(fd, "%s", prompt);	nr = 0;	p = line;	for(;;){		n = read(fd, p, 1);		if(n < 0){			close(fd);			close(ctl);			return -1;		}		if(n == 0 || *p == '\n' || *p == '\r'){			*p = '\0';			write(fd, "\n", 1);			close(fd);			close(ctl);			return nr;		}		if(*p == '\b'){			if(nr > 0){				nr--;				p--;			}		}else if(*p == 21){		/* cntrl-u */			fprint(fd, "\n%s", prompt);			nr = 0;			p = line;		}else{			nr++;			p++;		}		if(nr == len){			fprint(fd, "line too long; try again\n%s", prompt);			nr = 0;			p = line;		}	}	return -1;}