implement Dial;include "sys.m";	sys: Sys;include "draw.m";include "arg.m";include "keyring.m";	keyring: Keyring;include "security.m";	auth: Auth;include "sh.m";	sh: Sh;	Context: import sh; Dial: module {	init: fn(nil: ref Draw->Context, argv: list of string);}; badmodule(p: string){	sys->fprint(stderr(), "dial: cannot load %s: %r\n", p);	raise "fail:bad module";} DEFAULTALG := "none"; verbose := 0; init(drawctxt: ref Draw->Context, argv: list of string){	sys = load Sys Sys->PATH;	keyring = load Keyring Keyring->PATH;	auth = load Auth Auth->PATH;	if (auth == nil)		badmodule(Auth->PATH);	arg := load Arg Arg->PATH;	if (arg == nil)		badmodule(Arg->PATH);	sh = load Sh Sh->PATH;	if (sh == nil)		badmodule(Sh->PATH); 	auth->init();	alg: string;	keyfile: string;	doauth := 1;	arg->init(argv);	arg->setusage("dial [-A] [-k keyfile] [-a alg] addr command [arg...]");	while ((opt := arg->opt()) != 0) {		case opt {		'A' =>			doauth = 0;		'a' =>			alg = arg->earg();		'f' or		'k' =>			keyfile = arg->earg();			if (! (keyfile[0] == '/' || (len keyfile > 2 &&  keyfile[0:2] == "./")))				keyfile = "/usr/" + user() + "/keyring/" + keyfile;		'v' =>			verbose = 1;		* =>			arg->usage();		}	}	argv = arg->argv();	if (len argv < 2)		arg->usage();	arg = nil;	(addr, shcmd) := (hd argv, tl argv); 	if (doauth && alg == nil)		alg = DEFAULTALG; 	if (alg != nil && keyfile == nil) {		kd := "/usr/" + user() + "/keyring/";		if (exists(kd + addr))			keyfile = kd + addr;		else			keyfile = kd + "default";	}	cert: ref Keyring->Authinfo;	if (alg != nil) {		cert = keyring->readauthinfo(keyfile);		if (cert == nil) {			sys->fprint(stderr(), "dial: cannot read %s: %r\n", keyfile);			raise "fail:bad keyfile";		}	} 	(ok, c) := sys->dial(addr, nil);	if (ok == -1) {		sys->fprint(stderr(), "dial: cannot dial %s:: %r\n", addr);		raise "fail:errors";	}	user: string;	if (alg != nil) {		err: string;		(c.dfd, err) = auth->client(alg, cert, c.dfd);		if (c.dfd == nil) {			sys->fprint(stderr(), "dial: authentication failed: %s\n", err);			raise "fail:errors";		}		user = err;	}	sys->dup(c.dfd.fd, 0);	sys->dup(c.dfd.fd, 1);	c.dfd = c.cfd = nil;	ctxt := Context.new(drawctxt);	if (user != nil)		ctxt.set("user", sh->stringlist2list(user :: nil));	else		ctxt.set("user", nil);	ctxt.set("net", ref Sh->Listnode(nil, c.dir) :: nil);	ctxt.run(sh->stringlist2list(shcmd), 1);} exists(f: string): int{	(ok, nil) := sys->stat(f);	return ok != -1;} stderr(): ref Sys->FD{	return sys->fildes(2);} user(): string{	u := readfile("/dev/user");	if (u == nil)		return "nobody";	return u;} readfile(f: string): string{	fd := sys->open(f, sys->OREAD);	if(fd == nil)		return nil; 	buf := array[128] of byte;	n := sys->read(fd, buf, len buf);	if(n < 0)		return nil; 	return string buf[0:n];	}