Ejemplo n.º 1
0
size_t stdin_gotdata(struct handle *h, const void *data, size_t len, int err)
{
    if (err) {
	char buf[4096];
	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, err, 0,
		      buf, lenof(buf), NULL);
	buf[lenof(buf)-1] = '\0';
	if (buf[strlen(buf)-1] == '\n')
	    buf[strlen(buf)-1] = '\0';
	fprintf(stderr, "Unable to read from standard input: %s\n", buf);
	cleanup_exit(0);
    }

    noise_ultralight(NOISE_SOURCE_IOLEN, len);
    if (backend_connected(backend)) {
	if (len > 0) {
            return backend_send(backend, data, len);
	} else {
            backend_special(backend, SS_EOF, 0);
	    return 0;
	}
    } else
	return 0;
}
Ejemplo n.º 2
0
/*
 * Handle data from a local tty in PARMRK format.
 */
static void from_tty(void *vbuf, unsigned len)
{
    char *p, *q, *end, *buf = vbuf;
    static enum {NORMAL, FF, FF00} state = NORMAL;

    p = buf; end = buf + len;
    while (p < end) {
	switch (state) {
	    case NORMAL:
		if (*p == '\xff') {
		    p++;
		    state = FF;
		} else {
		    q = memchr(p, '\xff', end - p);
		    if (q == NULL) q = end;
                    backend_send(backend, p, q - p);
		    p = q;
		}
		break;
	    case FF:
		if (*p == '\xff') {
                    backend_send(backend, p, 1);
		    p++;
		    state = NORMAL;
		} else if (*p == '\0') {
		    p++;
		    state = FF00;
		} else abort();
		break;
	    case FF00:
		if (*p == '\0') {
                    backend_special(backend, SS_BRK, 0);
		} else {
		    /* 
		     * Pretend that PARMRK wasn't set.  This involves
		     * faking what INPCK and IGNPAR would have done if
		     * we hadn't overridden them.  Unfortunately, we
		     * can't do this entirely correctly because INPCK
		     * distinguishes between framing and parity
		     * errors, but PARMRK format represents both in
		     * the same way.  We assume that parity errors are
		     * more common than framing errors, and hence
		     * treat all input errors as being subject to
		     * INPCK.
		     */
		    if (orig_termios.c_iflag & INPCK) {
			/* If IGNPAR is set, we throw away the character. */
			if (!(orig_termios.c_iflag & IGNPAR)) {
			    /* PE/FE get passed on as NUL. */
			    *p = 0;
                            backend_send(backend, p, 1);
			}
		    } else {
			/* INPCK not set.  Assume we got a parity error. */
                        backend_send(backend, p, 1);
		    }
		}
		p++;
		state = NORMAL;
	}
    }
}
Ejemplo n.º 3
0
int main(int argc, char **argv)
{
    bool sending;
    int *fdlist;
    int fd;
    int i, fdstate;
    size_t fdsize;
    int exitcode;
    bool errors;
    enum TriState sanitise_stdout = AUTO, sanitise_stderr = AUTO;
    bool use_subsystem = false;
    bool just_test_share_exists = false;
    unsigned long now;
    struct winsize size;
    const struct BackendVtable *backvt;

    fdlist = NULL;
    fdsize = 0;
    /*
     * Initialise port and protocol to sensible defaults. (These
     * will be overridden by more or less anything.)
     */
    default_protocol = PROT_SSH;
    default_port = 22;

    bufchain_init(&stdout_data);
    bufchain_init(&stderr_data);
    bufchain_sink_init(&stdout_bcs, &stdout_data);
    bufchain_sink_init(&stderr_bcs, &stderr_data);
    stdout_bs = BinarySink_UPCAST(&stdout_bcs);
    stderr_bs = BinarySink_UPCAST(&stderr_bcs);
    outgoingeof = EOF_NO;

    flags = FLAG_STDERR_TTY;
    cmdline_tooltype |=
        (TOOLTYPE_HOST_ARG |
         TOOLTYPE_HOST_ARG_CAN_BE_SESSION |
         TOOLTYPE_HOST_ARG_PROTOCOL_PREFIX |
         TOOLTYPE_HOST_ARG_FROM_LAUNCHABLE_LOAD);

    stderr_tty_init();
    /*
     * Process the command line.
     */
    conf = conf_new();
    do_defaults(NULL, conf);
    loaded_session = false;
    default_protocol = conf_get_int(conf, CONF_protocol);
    default_port = conf_get_int(conf, CONF_port);
    errors = false;
    {
	/*
	 * Override the default protocol if PLINK_PROTOCOL is set.
	 */
	char *p = getenv("PLINK_PROTOCOL");
	if (p) {
            const struct BackendVtable *vt = backend_vt_from_name(p);
            if (vt) {
                default_protocol = vt->protocol;
                default_port = vt->default_port;
		conf_set_int(conf, CONF_protocol, default_protocol);
		conf_set_int(conf, CONF_port, default_port);
	    }
	}
    }
    while (--argc) {
	char *p = *++argv;
        int ret = cmdline_process_param(p, (argc > 1 ? argv[1] : NULL),
                                        1, conf);
        if (ret == -2) {
            fprintf(stderr,
                    "plink: option \"%s\" requires an argument\n", p);
            errors = true;
        } else if (ret == 2) {
            --argc, ++argv;
        } else if (ret == 1) {
            continue;
        } else if (!strcmp(p, "-batch")) {
            console_batch_mode = true;
        } else if (!strcmp(p, "-s")) {
            /* Save status to write to conf later. */
            use_subsystem = true;
        } else if (!strcmp(p, "-V") || !strcmp(p, "--version")) {
            version();
        } else if (!strcmp(p, "--help")) {
            usage();
            exit(0);
        } else if (!strcmp(p, "-pgpfp")) {
            pgp_fingerprints();
            exit(1);
        } else if (!strcmp(p, "-o")) {
            if (argc <= 1) {
                fprintf(stderr,
                        "plink: option \"-o\" requires an argument\n");
                errors = true;
            } else {
                --argc;
                /* Explicitly pass "plink" in place of appname for
                 * error reporting purposes. appname will have been
                 * set by be_foo.c to something more generic, probably
                 * "PuTTY". */
                provide_xrm_string(*++argv, "plink");
            }
        } else if (!strcmp(p, "-shareexists")) {
            just_test_share_exists = true;
        } else if (!strcmp(p, "-fuzznet")) {
            conf_set_int(conf, CONF_proxy_type, PROXY_FUZZ);
            conf_set_str(conf, CONF_proxy_telnet_command, "%host");
        } else if (!strcmp(p, "-sanitise-stdout") ||
                   !strcmp(p, "-sanitize-stdout")) {
            sanitise_stdout = FORCE_ON;
        } else if (!strcmp(p, "-no-sanitise-stdout") ||
                   !strcmp(p, "-no-sanitize-stdout")) {
            sanitise_stdout = FORCE_OFF;
        } else if (!strcmp(p, "-sanitise-stderr") ||
                   !strcmp(p, "-sanitize-stderr")) {
            sanitise_stderr = FORCE_ON;
        } else if (!strcmp(p, "-no-sanitise-stderr") ||
                   !strcmp(p, "-no-sanitize-stderr")) {
            sanitise_stderr = FORCE_OFF;
        } else if (!strcmp(p, "-no-antispoof")) {
            console_antispoof_prompt = false;
	} else if (*p != '-') {
            strbuf *cmdbuf = strbuf_new();

            while (argc > 0) {
                if (cmdbuf->len > 0)
                    put_byte(cmdbuf, ' '); /* add space separator */
                put_datapl(cmdbuf, ptrlen_from_asciz(p));
                if (--argc > 0)
                    p = *++argv;
            }

            conf_set_str(conf, CONF_remote_cmd, cmdbuf->s);
            conf_set_str(conf, CONF_remote_cmd2, "");
            conf_set_bool(conf, CONF_nopty, true);  /* command => no tty */

            strbuf_free(cmdbuf);
            break;		       /* done with cmdline */
        } else {
            fprintf(stderr, "plink: unknown option \"%s\"\n", p);
            errors = true;
	}
    }

    if (errors)
	return 1;

    if (!cmdline_host_ok(conf)) {
	usage();
    }

    prepare_session(conf);

    /*
     * Perform command-line overrides on session configuration.
     */
    cmdline_run_saved(conf);

    /*
     * If we have no better ideas for the remote username, use the local
     * one, as 'ssh' does.
     */
    if (conf_get_str(conf, CONF_username)[0] == '\0') {
	char *user = get_username();
	if (user) {
	    conf_set_str(conf, CONF_username, user);
	    sfree(user);
	}
    }

    /*
     * Apply subsystem status.
     */
    if (use_subsystem)
        conf_set_bool(conf, CONF_ssh_subsys, true);

    if (!*conf_get_str(conf, CONF_remote_cmd) &&
	!*conf_get_str(conf, CONF_remote_cmd2) &&
	!*conf_get_str(conf, CONF_ssh_nc_host))
	flags |= FLAG_INTERACTIVE;

    /*
     * Select protocol. This is farmed out into a table in a
     * separate file to enable an ssh-free variant.
     */
    backvt = backend_vt_from_proto(conf_get_int(conf, CONF_protocol));
    if (!backvt) {
	fprintf(stderr,
		"Internal fault: Unsupported protocol found\n");
	return 1;
    }

    /*
     * Block SIGPIPE, so that we'll get EPIPE individually on
     * particular network connections that go wrong.
     */
    putty_signal(SIGPIPE, SIG_IGN);

    /*
     * Set up the pipe we'll use to tell us about SIGWINCH.
     */
    if (pipe(signalpipe) < 0) {
	perror("pipe");
	exit(1);
    }
    /* We don't want the signal handler to block if the pipe's full. */
    nonblock(signalpipe[0]);
    nonblock(signalpipe[1]);
    cloexec(signalpipe[0]);
    cloexec(signalpipe[1]);
    putty_signal(SIGWINCH, sigwinch);

    /*
     * Now that we've got the SIGWINCH handler installed, try to find
     * out the initial terminal size.
     */
    if (ioctl(STDIN_FILENO, TIOCGWINSZ, &size) >= 0) {
	conf_set_int(conf, CONF_width, size.ws_col);
	conf_set_int(conf, CONF_height, size.ws_row);
    }

    /*
     * Decide whether to sanitise control sequences out of standard
     * output and standard error.
     *
     * If we weren't given a command-line override, we do this if (a)
     * the fd in question is pointing at a terminal, and (b) we aren't
     * trying to allocate a terminal as part of the session.
     *
     * (Rationale: the risk of control sequences is that they cause
     * confusion when sent to a local terminal, so if there isn't one,
     * no problem. Also, if we allocate a remote terminal, then we
     * sent a terminal type, i.e. we told it what kind of escape
     * sequences we _like_, i.e. we were expecting to receive some.)
     */
    if (sanitise_stdout == FORCE_ON ||
        (sanitise_stdout == AUTO && isatty(STDOUT_FILENO) &&
         conf_get_bool(conf, CONF_nopty))) {
        stdout_scc = stripctrl_new(stdout_bs, true, L'\0');
        stdout_bs = BinarySink_UPCAST(stdout_scc);
    }
    if (sanitise_stderr == FORCE_ON ||
        (sanitise_stderr == AUTO && isatty(STDERR_FILENO) &&
         conf_get_bool(conf, CONF_nopty))) {
        stderr_scc = stripctrl_new(stderr_bs, true, L'\0');
        stderr_bs = BinarySink_UPCAST(stderr_scc);
    }

    sk_init();
    uxsel_init();

    /*
     * Plink doesn't provide any way to add forwardings after the
     * connection is set up, so if there are none now, we can safely set
     * the "simple" flag.
     */
    if (conf_get_int(conf, CONF_protocol) == PROT_SSH &&
	!conf_get_bool(conf, CONF_x11_forward) &&
	!conf_get_bool(conf, CONF_agentfwd) &&
	!conf_get_str_nthstrkey(conf, CONF_portfwd, 0))
	conf_set_bool(conf, CONF_ssh_simple, true);

    if (just_test_share_exists) {
        if (!backvt->test_for_upstream) {
            fprintf(stderr, "Connection sharing not supported for connection "
                    "type '%s'\n", backvt->name);
            return 1;
        }
        if (backvt->test_for_upstream(conf_get_str(conf, CONF_host),
                                      conf_get_int(conf, CONF_port), conf))
            return 0;
        else
            return 1;
    }

    /*
     * Start up the connection.
     */
    logctx = log_init(default_logpolicy, conf);
    {
	const char *error;
	char *realhost;
	/* nodelay is only useful if stdin is a terminal device */
	bool nodelay = conf_get_bool(conf, CONF_tcp_nodelay) && isatty(0);

	/* This is a good place for a fuzzer to fork us. */
#ifdef __AFL_HAVE_MANUAL_CONTROL
	__AFL_INIT();
#endif

        error = backend_init(backvt, plink_seat, &backend, logctx, conf,
                             conf_get_str(conf, CONF_host),
                             conf_get_int(conf, CONF_port),
                             &realhost, nodelay,
                             conf_get_bool(conf, CONF_tcp_keepalives));
	if (error) {
	    fprintf(stderr, "Unable to open connection:\n%s\n", error);
	    return 1;
	}
        ldisc_create(conf, NULL, backend, plink_seat);
	sfree(realhost);
    }

    /*
     * Set up the initial console mode. We don't care if this call
     * fails, because we know we aren't necessarily running in a
     * console.
     */
    local_tty = (tcgetattr(STDIN_FILENO, &orig_termios) == 0);
    atexit(cleanup_termios);
    seat_echoedit_update(plink_seat, 1, 1);
    sending = false;
    now = GETTICKCOUNT();

    pollwrapper *pw = pollwrap_new();

    while (1) {
	int rwx;
	int ret;
        unsigned long next;

        pollwrap_clear(pw);

	pollwrap_add_fd_rwx(pw, signalpipe[0], SELECT_R);

	if (!sending &&
            backend_connected(backend) &&
            backend_sendok(backend) &&
            backend_sendbuffer(backend) < MAX_STDIN_BACKLOG) {
	    /* If we're OK to send, then try to read from stdin. */
            pollwrap_add_fd_rwx(pw, STDIN_FILENO, SELECT_R);
	}

	if (bufchain_size(&stdout_data) > 0) {
	    /* If we have data for stdout, try to write to stdout. */
            pollwrap_add_fd_rwx(pw, STDOUT_FILENO, SELECT_W);
	}

	if (bufchain_size(&stderr_data) > 0) {
	    /* If we have data for stderr, try to write to stderr. */
            pollwrap_add_fd_rwx(pw, STDERR_FILENO, SELECT_W);
	}

	/* Count the currently active fds. */
	i = 0;
	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
	     fd = next_fd(&fdstate, &rwx)) i++;

	/* Expand the fdlist buffer if necessary. */
        sgrowarray(fdlist, fdsize, i);

	/*
	 * Add all currently open fds to pw, and store them in fdlist
	 * as well.
	 */
	int fdcount = 0;
	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
	     fd = next_fd(&fdstate, &rwx)) {
	    fdlist[fdcount++] = fd;
            pollwrap_add_fd_rwx(pw, fd, rwx);
	}

        if (toplevel_callback_pending()) {
            ret = pollwrap_poll_instant(pw);
        } else if (run_timers(now, &next)) {
            do {
                unsigned long then;
                long ticks;

		then = now;
		now = GETTICKCOUNT();
		if (now - then > next - then)
		    ticks = 0;
		else
		    ticks = next - now;

                bool overflow = false;
                if (ticks > INT_MAX) {
                    ticks = INT_MAX;
                    overflow = true;
                }

                ret = pollwrap_poll_timeout(pw, ticks);
                if (ret == 0 && !overflow)
                    now = next;
                else
                    now = GETTICKCOUNT();
            } while (ret < 0 && errno == EINTR);
        } else {
            ret = pollwrap_poll_endless(pw);
        }

        if (ret < 0 && errno == EINTR)
            continue;

	if (ret < 0) {
	    perror("poll");
	    exit(1);
	}

	for (i = 0; i < fdcount; i++) {
	    fd = fdlist[i];
            int rwx = pollwrap_get_fd_rwx(pw, fd);
            /*
             * We must process exceptional notifications before
             * ordinary readability ones, or we may go straight
             * past the urgent marker.
             */
	    if (rwx & SELECT_X)
		select_result(fd, SELECT_X);
	    if (rwx & SELECT_R)
		select_result(fd, SELECT_R);
	    if (rwx & SELECT_W)
		select_result(fd, SELECT_W);
	}

	if (pollwrap_check_fd_rwx(pw, signalpipe[0], SELECT_R)) {
	    char c[1];
	    struct winsize size;
	    if (read(signalpipe[0], c, 1) <= 0)
		/* ignore error */;
	    /* ignore its value; it'll be `x' */
	    if (ioctl(STDIN_FILENO, TIOCGWINSZ, (void *)&size) >= 0)
                backend_size(backend, size.ws_col, size.ws_row);
	}

	if (pollwrap_check_fd_rwx(pw, STDIN_FILENO, SELECT_R)) {
	    char buf[4096];
	    int ret;

            if (backend_connected(backend)) {
		ret = read(STDIN_FILENO, buf, sizeof(buf));
                noise_ultralight(NOISE_SOURCE_IOLEN, ret);
		if (ret < 0) {
		    perror("stdin: read");
		    exit(1);
		} else if (ret == 0) {
                    backend_special(backend, SS_EOF, 0);
		    sending = false;   /* send nothing further after this */
		} else {
		    if (local_tty)
			from_tty(buf, ret);
		    else
                        backend_send(backend, buf, ret);
		}
	    }
	}

	if (pollwrap_check_fd_rwx(pw, STDOUT_FILENO, SELECT_W)) {
            backend_unthrottle(backend, try_output(false));
	}

	if (pollwrap_check_fd_rwx(pw, STDERR_FILENO, SELECT_W)) {
            backend_unthrottle(backend, try_output(true));
	}

        run_toplevel_callbacks();

        if (!backend_connected(backend) &&
	    bufchain_size(&stdout_data) == 0 &&
	    bufchain_size(&stderr_data) == 0)
	    break;		       /* we closed the connection */
    }
    exitcode = backend_exitcode(backend);
    if (exitcode < 0) {
	fprintf(stderr, "Remote process exit code unavailable\n");
	exitcode = 1;		       /* this is an error condition */
    }
    cleanup_exit(exitcode);
    return exitcode;		       /* shouldn't happen, but placates gcc */
}
Ejemplo n.º 4
0
void ldisc_send(Ldisc *ldisc, const void *vbuf, int len, bool interactive)
{
    const char *buf = (const char *)vbuf;
    int keyflag = 0;

    assert(ldisc->term);
    assert(len);

    if (interactive) {
        /*
         * Interrupt a paste from the clipboard, if one was in
         * progress when the user pressed a key. This is easier than
         * buffering the current piece of data and saving it until the
         * terminal has finished pasting, and has the potential side
         * benefit of permitting a user to cancel an accidental huge
         * paste.
         */
        term_nopaste(ldisc->term);
    }

    /*
     * Less than zero means null terminated special string.
     */
    if (len < 0) {
	len = strlen(buf);
	keyflag = KCTRL('@');
    }
    /*
     * Either perform local editing, or just send characters.
     */
    if (EDITING) {
	while (len--) {
	    int c;
	    c = (unsigned char)(*buf++) + keyflag;
	    if (!interactive && c == '\r')
		c += KCTRL('@');
	    switch (ldisc->quotenext ? ' ' : c) {
		/*
		 * ^h/^?: delete, and output BSBs, to return to
		 * last character boundary (in UTF-8 mode this may
		 * be more than one byte)
		 * ^w: delete, and output BSBs, to return to last
		 * space/nonspace boundary
		 * ^u: delete, and output BSBs, to return to BOL
		 * ^c: Do a ^u then send a telnet IP
		 * ^z: Do a ^u then send a telnet SUSP
		 * ^\: Do a ^u then send a telnet ABORT
		 * ^r: echo "^R\n" and redraw line
		 * ^v: quote next char
		 * ^d: if at BOL, end of file and close connection,
		 * else send line and reset to BOL
		 * ^m: send line-plus-\r\n and reset to BOL
		 */
	      case KCTRL('H'):
	      case KCTRL('?'):	       /* backspace/delete */
		if (ldisc->buflen > 0) {
		    do {
			if (ECHOING)
			    bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
			ldisc->buflen--;
		    } while (!char_start(ldisc, ldisc->buf[ldisc->buflen]));
		}
		break;
	      case CTRL('W'):	       /* delete word */
		while (ldisc->buflen > 0) {
		    if (ECHOING)
			bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
		    ldisc->buflen--;
		    if (ldisc->buflen > 0 &&
			isspace((unsigned char)ldisc->buf[ldisc->buflen-1]) &&
			!isspace((unsigned char)ldisc->buf[ldisc->buflen]))
			break;
		}
		break;
	      case CTRL('U'):	       /* delete line */
	      case CTRL('C'):	       /* Send IP */
	      case CTRL('\\'):	       /* Quit */
	      case CTRL('Z'):	       /* Suspend */
		while (ldisc->buflen > 0) {
		    if (ECHOING)
			bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
		    ldisc->buflen--;
		}
                backend_special(ldisc->backend, SS_EL, 0);
                /*
                 * We don't send IP, SUSP or ABORT if the user has
                 * configured telnet specials off! This breaks
                 * talkers otherwise.
                 */
                if (!ldisc->telnet_keyboard)
                    goto default_case;
		if (c == CTRL('C'))
                    backend_special(ldisc->backend, SS_IP, 0);
		if (c == CTRL('Z'))
                    backend_special(ldisc->backend, SS_SUSP, 0);
		if (c == CTRL('\\'))
                    backend_special(ldisc->backend, SS_ABORT, 0);
		break;
	      case CTRL('R'):	       /* redraw line */
		if (ECHOING) {
		    int i;
		    c_write(ldisc, "^R\r\n", 4);
		    for (i = 0; i < ldisc->buflen; i++)
			pwrite(ldisc, ldisc->buf[i]);
		}
		break;
	      case CTRL('V'):	       /* quote next char */
		ldisc->quotenext = true;
		break;
	      case CTRL('D'):	       /* logout or send */
		if (ldisc->buflen == 0) {
                    backend_special(ldisc->backend, SS_EOF, 0);
		} else {
                    backend_send(ldisc->backend, ldisc->buf, ldisc->buflen);
		    ldisc->buflen = 0;
		}
		break;
		/*
		 * This particularly hideous bit of code from RDB
		 * allows ordinary ^M^J to do the same thing as
		 * magic-^M when in Raw protocol. The line `case
		 * KCTRL('M'):' is _inside_ the if block. Thus:
		 * 
		 *  - receiving regular ^M goes straight to the
		 *    default clause and inserts as a literal ^M.
		 *  - receiving regular ^J _not_ directly after a
		 *    literal ^M (or not in Raw protocol) fails the
		 *    if condition, leaps to the bottom of the if,
		 *    and falls through into the default clause
		 *    again.
		 *  - receiving regular ^J just after a literal ^M
		 *    in Raw protocol passes the if condition,
		 *    deletes the literal ^M, and falls through
		 *    into the magic-^M code
		 *  - receiving a magic-^M empties the line buffer,
		 *    signals end-of-line in one of the various
		 *    entertaining ways, and _doesn't_ fall out of
		 *    the bottom of the if and through to the
		 *    default clause because of the break.
		 */
	      case CTRL('J'):
		if (ldisc->protocol == PROT_RAW &&
		    ldisc->buflen > 0 && ldisc->buf[ldisc->buflen - 1] == '\r') {
		    if (ECHOING)
			bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
		    ldisc->buflen--;
		    /* FALLTHROUGH */
	      case KCTRL('M'):	       /* send with newline */
		    if (ldisc->buflen > 0)
                        backend_send(ldisc->backend,
                                     ldisc->buf, ldisc->buflen);
		    if (ldisc->protocol == PROT_RAW)
                        backend_send(ldisc->backend, "\r\n", 2);
		    else if (ldisc->protocol == PROT_TELNET && ldisc->telnet_newline)
                        backend_special(ldisc->backend, SS_EOL, 0);
		    else
                        backend_send(ldisc->backend, "\r", 1);
		    if (ECHOING)
			c_write(ldisc, "\r\n", 2);
		    ldisc->buflen = 0;
		    break;
		}
		/* FALLTHROUGH */
	      default:		       /* get to this label from ^V handler */
                default_case:
                sgrowarray(ldisc->buf, ldisc->bufsiz, ldisc->buflen);
		ldisc->buf[ldisc->buflen++] = c;
		if (ECHOING)
		    pwrite(ldisc, (unsigned char) c);
		ldisc->quotenext = false;
		break;
	    }
	}
    } else {
	if (ldisc->buflen != 0) {
            backend_send(ldisc->backend, ldisc->buf, ldisc->buflen);
	    while (ldisc->buflen > 0) {
		bsb(ldisc, plen(ldisc, ldisc->buf[ldisc->buflen - 1]));
		ldisc->buflen--;
	    }
	}
	if (len > 0) {
	    if (ECHOING)
		c_write(ldisc, buf, len);
	    if (keyflag && ldisc->protocol == PROT_TELNET && len == 1) {
		switch (buf[0]) {
		  case CTRL('M'):
		    if (ldisc->protocol == PROT_TELNET && ldisc->telnet_newline)
                        backend_special(ldisc->backend, SS_EOL, 0);
		    else
                        backend_send(ldisc->backend, "\r", 1);
		    break;
		  case CTRL('?'):
		  case CTRL('H'):
		    if (ldisc->telnet_keyboard) {
                        backend_special(ldisc->backend, SS_EC, 0);
			break;
		    }
		  case CTRL('C'):
		    if (ldisc->telnet_keyboard) {
                        backend_special(ldisc->backend, SS_IP, 0);
			break;
		    }
		  case CTRL('Z'):
		    if (ldisc->telnet_keyboard) {
                        backend_special(ldisc->backend, SS_SUSP, 0);
			break;
		    }

		  default:
                    backend_send(ldisc->backend, buf, len);
		    break;
		}
	    } else
                backend_send(ldisc->backend, buf, len);
	}
    }
}