#include <u.h>#include <libc.h> void	getstr(int, char*, int); voidmain(void){	char luser[128], ruser[128], term[128], err[128]; 	getstr(0, err, sizeof(err));	getstr(0, ruser, sizeof(ruser));	getstr(0, luser, sizeof(luser));	getstr(0, term, sizeof(term));	write(0, "", 1); 	if(luser[0] == '\0')		strncpy(luser, ruser, sizeof luser);	luser[sizeof luser-1] = '\0';	syslog(0, "telnet", "rlogind %s", luser);	execl("/bin/ip/telnetd", "telnetd", "-n", "-u", luser, nil);	fprint(2, "can't exec con service: %r\n");	exits("can't exec");} voidgetstr(int fd, char *str, int len){	char c;	int n; 	while(--len > 0){		n = read(fd, &c, 1);		if(n < 0)			return;		if(n == 0)			continue;		*str++ = c;		if(c == 0)			break;	}	*str = '\0';}