commands.c

经典的unix下telnet的c代码

    for (;;) {
	if (fgets(line, sizeof(line), rcfile) == NULL)
	    break;
	if (line[0] == 0)
	    break;
	if (line[0] == '#')
	    continue;
	if (gotmachine) {
	    if (!isspace(line[0]))
		gotmachine = 0;
	}
	if (gotmachine == 0) {
	    if (isspace(line[0]))
		continue;
	    if (strncasecmp(line, m1, l1) == 0)
		strncpy(line, &line[l1], sizeof(line) - l1);
	    else if (strncasecmp(line, m2, l2) == 0)
		strncpy(line, &line[l2], sizeof(line) - l2);
	    else if (strncasecmp(line, "DEFAULT", 7) == 0)
		strncpy(line, &line[7], sizeof(line) - 7);
	    else
		continue;
	    if (line[0] != ' ' && line[0] != '\t' && line[0] != '\n')
		continue;
	    gotmachine = 1;
	}
	makeargv();
	if (margv[0] == 0)
	    continue;
	c = getcmd(margv[0]);
	if (Ambiguous(c)) {
	    printf("?Ambiguous command: %s\r\n", margv[0]);
	    continue;
	}
	if (c == 0) {
	    printf("?Invalid command: %s\r\n", margv[0]);
	    continue;
	}
	/*
	 * This should never happen...
	 */
	if (c->needconnect && !connected) {
	    printf("?Need to be connected first for %s.\r\n", margv[0]);
	    continue;
	}
	(*c->handler)(margc, margv);
    }
    fclose(rcfile);
}


    int
tn(argc, argv)
    int argc;
    char *argv[];
{
    struct addrinfo hints, *res, *res0;
    int error;
    struct sockaddr_in sin;
    unsigned long temp;
    extern char *inet_ntoa();
#if	defined(IP_OPTIONS) && defined(IPPROTO_IP)
    char *srp = 0;
    int srlen;
#endif
    char *cmd, *hostp = 0, *portp = 0, *user = 0, *aliasp = 0;
    int retry;
#ifdef NI_WITHSCOPEID
    const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID;
#else
    const int niflags = NI_NUMERICHOST;
#endif

    /* clear the socket address prior to use */
    memset((char *)&sin, 0, sizeof(sin));

    if (connected) {
	printf("?Already connected to %s\r\n", hostname);
	return 0;
    }
    if (argc < 2) {
	strlcpy(line, "open ", sizeof(line));
	printf("(to) ");
	(void) fgets(&line[strlen(line)], sizeof(line) - strlen(line), stdin);
	makeargv();
	argc = margc;
	argv = margv;
    }
    cmd = *argv;
    --argc; ++argv;
    while (argc) {
	if (strcmp(*argv, "help") == 0 || isprefix(*argv, "?"))
	    goto usage;
	if (strcmp(*argv, "-l") == 0) {
	    --argc; ++argv;
	    if (argc == 0)
		goto usage;
	    if ((user = strdup(*argv++)) == NULL)
		err(1, "strdup");
	    --argc;
	    continue;
	}
	if (strcmp(*argv, "-b") == 0) {
	    --argc; ++argv;
	    if (argc == 0)
		goto usage;
	    aliasp = *argv++;
	    --argc;
	    continue;
	}
	if (strcmp(*argv, "-a") == 0) {
	    --argc; ++argv;
	    autologin = 1;
	    continue;
	}
	if (hostp == 0) {
	    hostp = *argv++;
	    --argc;
	    continue;
	}
	if (portp == 0) {
	    portp = *argv++;
	    --argc;
	    continue;
	}
    usage:
	printf("usage: %s [-l user] [-a] host-name [port]\r\n", cmd);
	return 0;
    }
    if (hostp == 0)
	goto usage;

#if	defined(IP_OPTIONS) && defined(IPPROTO_IP)
    if (hostp[0] == '@' || hostp[0] == '!') {
	if ((hostname = strrchr(hostp, ':')) == NULL)
	    hostname = strrchr(hostp, '@');
	hostname++;
	srp = 0;
	temp = sourceroute(hostp, &srp, &srlen);
	if (temp == 0) {
	    herror(srp);
	    return 0;
	} else if (temp == -1) {
	    printf("Bad source route option: %s\r\n", hostp);
	    return 0;
	} else {
	    abort();
	}
    } else
#endif
    {
	hostname = hostp;
	memset(&hints, 0, sizeof(hints));
	hints.ai_family = family;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_flags = AI_CANONNAME;
	if (portp == NULL) {
	    portp = "telnet";
	    telnetport = 1;
	} else if (*portp == '-') {
	    portp++;
	    telnetport = 1;
	} else
	    telnetport = 0;
	h_errno = 0;
	error = getaddrinfo(hostp, portp, &hints, &res0);
	if (error) {
	    if (error == EAI_SERVICE)
		warnx("%s: bad port", portp);
	    else
		warnx("%s: %s", hostp, gai_strerror(error));
	    if (h_errno)
		herror(hostp);
	    return 0;
	}
    }

    net = -1;
    retry = 0;
    for (res = res0; res; res = res->ai_next) {
	if (1 /* retry */) {
	    char hbuf[NI_MAXHOST];

	    if (getnameinfo(res->ai_addr, res->ai_addrlen, hbuf, sizeof(hbuf),
		    NULL, 0, niflags) != 0) {
		strlcpy(hbuf, "(invalid)", sizeof(hbuf));
	    }
	    printf("Trying %s...\r\n", hbuf);
	}
	net = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
	if (net < 0)
	    continue;

	if (aliasp) {
	    struct addrinfo ahints, *ares;

	    memset(&ahints, 0, sizeof(ahints));
	    ahints.ai_family = family;
	    ahints.ai_socktype = SOCK_STREAM;
	    ahints.ai_flags = AI_PASSIVE;
	    error = getaddrinfo(aliasp, "0", &ahints, &ares);
	    if (error) {
		warn("%s: %s", aliasp, gai_strerror(error));
		close(net);
		continue;
	    }
	    if (bind(net, ares->ai_addr, ares->ai_addrlen) < 0) {
		perror(aliasp);
		(void) close(net);   /* dump descriptor */
		freeaddrinfo(ares);
		continue;
            }
	    freeaddrinfo(ares);
	}
#if	defined(IP_OPTIONS) && defined(IPPROTO_IP)
	if (srp && res->ai_family == AF_INET
	 && setsockopt(net, IPPROTO_IP, IP_OPTIONS, (char *)srp, srlen) < 0)
		perror("setsockopt (IP_OPTIONS)");
#endif
#if	defined(IPPROTO_IP) && defined(IP_TOS)
	if (res->ai_family == AF_INET) {
# if	defined(HAS_GETTOS)
	    struct tosent *tp;
	    if (tos < 0 && (tp = gettosbyname("telnet", "tcp")))
		tos = tp->t_tos;
# endif
	    if (tos < 0)
		tos = IPTOS_LOWDELAY;	/* Low Delay bit */
	    if (tos
		&& (setsockopt(net, IPPROTO_IP, IP_TOS,
		    (void *)&tos, sizeof(int)) < 0)
		&& (errno != ENOPROTOOPT))
		    perror("telnet: setsockopt (IP_TOS) (ignored)");
	}
#endif	/* defined(IPPROTO_IP) && defined(IP_TOS) */

	if (debug && SetSockOpt(net, SOL_SOCKET, SO_DEBUG, 1) < 0) {
		perror("setsockopt (SO_DEBUG)");
	}

	if (connect(net, res->ai_addr, res->ai_addrlen) < 0) {
	    char hbuf[NI_MAXHOST];

	    if (getnameinfo(res->ai_addr, res->ai_addrlen, hbuf, sizeof(hbuf),
		    NULL, 0, niflags) != 0) {
		strlcpy(hbuf, "(invalid)", sizeof(hbuf));
	    }
	    fprintf(stderr, "telnet: connect to address %s: %s\n", hbuf,
		strerror(errno));

	    close(net);
	    net = -1;
	    retry++;
	    continue;
	}

	connected++;
#if	defined(AUTHENTICATION) || defined(ENCRYPTION)
	auth_encrypt_connect(connected);
#endif	/* defined(AUTHENTICATION) */
	break;
    }
    freeaddrinfo(res0);
    if (net < 0) {
	return 0;
    }
    cmdrc(hostp, hostname);
    if (autologin && user == NULL) {
	struct passwd *pw;

	user = getenv("USER");
	if (user == NULL ||
	    ((pw = getpwnam(user)) && pw->pw_uid != getuid())) {
		if ((pw = getpwuid(getuid())) != NULL)
			user = pw->pw_name;
		else
			user = NULL;
	}
    }
    if (user) {
	env_define((unsigned char *)"USER", (unsigned char *)user);
	env_export((unsigned char *)"USER");
    }
    (void) call(status, "status", "notmuch", 0);
    if (setjmp(peerdied) == 0)
	telnet(user);
    (void) NetClose(net);
    ExitString("Connection closed by foreign host.\r\n",1);
    /*NOTREACHED*/
    return 0;
}

#define HELPINDENT (sizeof ("connect"))

static char
	openhelp[] =	"connect to a site",
	closehelp[] =	"close current connection",
	logouthelp[] =	"forcibly logout remote user and close the connection",
	quithelp[] =	"exit telnet",
	statushelp[] =	"print status information",
	helphelp[] =	"print help information",
	sendhelp[] =	"transmit special characters ('send ?' for more)",
	sethelp[] = 	"set operating parameters ('set ?' for more)",
	unsethelp[] = 	"unset operating parameters ('unset ?' for more)",
	togglestring[] ="toggle operating parameters ('toggle ?' for more)",
	slchelp[] =	"change state of special charaters ('slc ?' for more)",
	displayhelp[] =	"display operating parameters",
#if	defined(TN3270) && defined(unix)
	transcomhelp[] = "specify Unix command for transparent mode pipe",
#endif	/* defined(TN3270) && defined(unix) */
#if	defined(AUTHENTICATION)
	authhelp[] =	"turn on (off) authentication ('auth ?' for more)",
#endif
#if     defined(ENCRYPTION)
        encrypthelp[] = "turn on (off) encryption ('encrypt ?' for more)",
#endif
	zhelp[] =	"suspend telnet",
#ifdef SKEY
	skeyhelp[] =	"compute response to s/key challenge",
#endif
	shellhelp[] =	"invoke a subshell",
	envhelp[] =	"change environment variables ('environ ?' for more)",
	modestring[] = "try to enter line or character mode ('mode ?' for more)";

static int	help(int, char**);

static Command cmdtab[] = {
	{ "close",	closehelp,	bye,		1 },
	{ "logout",	logouthelp,	logout,		1 },
	{ "display",	displayhelp,	display,	0 },
	{ "mode",	modestring,	modecmd,	0 },
	{ "open",	openhelp,	tn,		0 },
	{ "quit",	quithelp,	quit,		0 },
	{ "send",	sendhelp,	sendcmd,	0 },
	{ "set",	sethelp,	setcmd,		0 },
	{ "unset",	unsethelp,	unsetcmd,	0 },
	{ "status",	statushelp,	status,		0 },
	{ "toggle",	togglestring,	toggle,		0 },
	{ "slc",	slchelp,	slccmd,		0 },
#if	defined(TN3270) && defined(unix)
	{ "transcom",	transcomhelp,	settranscom,	0 },
#endif	/* defined(TN3270) && defined(unix) */
#if	defined(AUTHENTICATION)
	{ "auth",	authhelp,	auth_cmd,	0 },
#endif
#if    defined(ENCRYPTION)
	{ "encrypt",    encrypthelp,    encrypt_cmd,    0 },
#endif

	{ "z",		zhelp,		telnetsuspend,	0 },
#if	defined(TN3270)
	{ "!",		shellhelp,	shell,		1 },
#else
	{ "!",		shellhelp,	shell,		0 },
#endif
	{ "environ",	envhelp,	env_cmd,	0 },
	{ "?",		helphelp,	help,		0 },
#if	defined(SKEY)
	{ "skey",	skeyhelp,	skey_calc,	0 },
#endif		
	{ 0,		0,		0,		0 }
};

static char	crmodhelp[] =	"deprecated command -- use 'toggle crmod' instead";
static char	escapehelp[] =	"deprecated command -- use 'set escape' instead";

static Command cmdtab2[] = {
	{ "help",	0,		help,		0 },
	{ "escape",	escapehelp,	setescape,	0 },
	{ "crmod",	crmodhelp,	togcrmod,	0 },
	{ 0,		0,		0,		0 }
};


/*
 * Call routine with argc, argv set from args (terminated by 0).
 */

    /*VARARGS1*/
    static int
call(intrtn_t routine, ...)
{
    va_list ap;
    char *args[100];
    int argno = 0;

    va_start(ap, routine);
    while ((args[argno++] = va_arg(ap, char *)) != 0);
    va_end(ap);
    return (*routine)(argno-1, args);
}


    static Command *
getcmd(name)
    char *name;
{
    Command *cm;

    if ((cm = (Command *) genget(name, (char **) cmdtab, sizeof(Command))))
	return cm;
    return (Command *) genget(name, (char **) cmdtab2, sizeof(Command));
}

    void
command(top, tbuf, cnt)
    int top;
    char *tbuf;
    int cnt;
{
    Command *c;

    setcommandmode();
    if (!top) {
	putchar('\n');
#if	defined(unix)
    } else {
	(void) signal(SIGINT, SIG_DFL);
	(void) signal(SIGQUIT, SIG_DFL);
#endif	/* defined(unix) */
    }
    for (;;) {
	if (rlogin == _POSIX_VDISABLE)
		printf("%s> ", prompt);
	if (tbuf) {
	    char *cp;
	    cp = line;
	    while (cnt > 0 && (*cp++ = *tbuf++) != '\n')
		cnt--;
	    tbuf = 0;
	    if (cp == line || *--cp != '\n' || cp == line)
		goto getline;
	    *cp = '\0';
	    if (rlogin == _POSIX_VDISABLE)
		printf("%s\r\n", line);
	} else {
	getline:
	    if (rlogin != _POSIX_VDISABLE)
		printf("%s> ", prompt);
	    if (fgets(line, sizeof(line), stdin) == NULL) {
		if (feof(stdin) || ferror(stdin)) {
		    (void) quit();
		    /*NOTREACHED*/
		}
		break;
	    }
	}
	if (line[0] == 0)
	    break;
	makeargv();
	if (margv[0] == 0) {
	    break;
	}
	c = getcmd(margv[0]);
	if (Ambiguous(c)) {
	    printf("?Ambiguous command\r\n");
	    continue;
	}
	if (c == 0) {
	    printf("?Invalid command\r\n");
	    continue;
	}
	if (c->needconnect && !connected) {
	    printf("?Need to be connected first.\r\n");
	    continue;
	}
	if ((*c->handler)(margc, margv)) {
	    break;
	}
    }
    if (!top) {
	if (!connected) {
	    longjmp(toplevel, 1);
	    /*NOTREACHED*/
	}
#if	defined(TN3270)
	if (shell_active == 0) {
	    setconnmode(0);
	}
#else	/* defined(TN3270) */
	setconnmode(0);
#endif	/* defined(TN3270) */
    }
}

/*
 * Help command.
 */
	static int
help(argc, argv)
	int argc;
	char *argv[];
{
	Command *c;

	if (argc == 1) {
		printf("Commands may be abbreviated.  Commands are:\r\n\r\n");
		for (c = cmdtab; c->name; c++)
			if (c->help) {
				printf("%-*s\t%s\r\n", (int)HELPINDENT, c->name,
								    c->help);
			}
		return 0;
	}
	while (--argc > 0) {
		char *arg;
		arg = *++argv;
		c = getcmd(arg);
		if (Ambiguous(c))
			printf("?Ambiguous help command %s\r\n", arg);
		else if (c == (Command *)0)
			printf("?Invalid help command %s\r\n", arg);
		else
			printf("%s\r\n", c->help);
	}
	return 0;
}

#if	defined(IP_OPTIONS) && defined(IPPROTO_IP)

/*
 * Source route is handed in as
 *	[!]@hop1@hop2...[@|:]dst
 * If the leading ! is present, it is a
 * strict source route, otherwise it is
 * assmed to be a loose source route.
 *
 * We fill in the source route option as
 *	hop1,hop2,hop3...dest
 * and return a pointer to hop1, which will
 * be the address to connect() to.
 *
 * Arguments:
 *	arg:	pointer to route list to decipher
 *
 *	cpp: 	If *cpp is not equal to NULL, this is a
 *		pointer to a pointer to a character array
 *		that should be filled in with the option.
 *
 *	lenp:	pointer to an integer that contains the
 *		length of *cpp if *cpp != NULL.
 *
 * Return values:
 *
 *	Returns the address of the host to connect to.  If the
 *	return value is -1, there was a syntax error in the
 *	option, either unknown characters, or too many hosts.
 *	If the return val