GUACAMOLE-860: [WIP] Interim buildout of TN5250 support.

.gitignore

@@ -46,3 +46,5 @@ stamp-h1
 # Generated docs
 doc/doxygen-output
 
+# IDE Configuration
+nbproject/

Makefile.am

@@ -39,6 +39,7 @@ DIST_SUBDIRS =               \
     src/protocols/rdp        \
     src/protocols/ssh        \
     src/protocols/telnet     \
+    src/protocols/tn5250     \
     src/protocols/vnc
 
 SUBDIRS =        \
@@ -71,6 +72,7 @@ endif
 
 if ENABLE_TELNET
 SUBDIRS += src/protocols/telnet
+SUBDIRS += src/protocols/tn5250
 endif
 
 if ENABLE_VNC

configure.ac

@@ -1382,6 +1382,7 @@ AC_CONFIG_FILES([Makefile
                  src/protocols/rdp/tests/Makefile
                  src/protocols/ssh/Makefile
                  src/protocols/telnet/Makefile
+                 src/protocols/tn5250/Makefile
                  src/protocols/vnc/Makefile])
 AC_OUTPUT
 
@@ -1447,6 +1448,7 @@ $PACKAGE_NAME version $PACKAGE_VERSION
       RDP ........... ${build_rdp}
       SSH ........... ${build_ssh}
       Telnet ........ ${build_telnet}
+      TN5250 ........ ${build_telnet}
       VNC ........... ${build_vnc}
 
    Services / tools:

src/protocols/tn5250/Makefile.am

@@ -0,0 +1,65 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+# NOTE: Parts of this file (Makefile.am) are automatically transcluded verbatim
+# into Makefile.in. Though the build system (GNU Autotools) automatically adds
+# its own license boilerplate to the generated Makefile.in, that boilerplate
+# does not apply to the transcluded portions of Makefile.am which are licensed
+# to you by the ASF under the Apache License, Version 2.0, as described above.
+#
+
+AUTOMAKE_OPTIONS = foreign
+ACLOCAL_AMFLAGS = -I m4
+
+lib_LTLIBRARIES = libguac-client-tn5250.la
+
+libguac_client_tn5250_la_SOURCES = \
+    argv.c                         \
+    client.c                       \
+    clipboard.c                    \
+    input.c                        \
+    pipe.c                         \
+    settings.c                     \
+    tn5250.c                       \
+    user.c
+
+noinst_HEADERS = \
+    argv.h       \
+    client.h     \
+    clipboard.h  \
+    input.h      \
+    pipe.h       \
+    settings.h   \
+    tn5250.h     \
+    user.h
+
+libguac_client_tn5250_la_CFLAGS = \
+    -Werror -Wall -Iinclude       \
+    @LIBGUAC_INCLUDE@             \
+    @TERMINAL_INCLUDE@
+
+libguac_client_tn5250_la_LIBADD = \
+    @COMMON_LTLIB@                \
+    @LIBGUAC_LTLIB@               \
+    @TERMINAL_LTLIB@
+
+libguac_client_tn5250_la_LDFLAGS = \
+    -version-info 0:0:0            \
+    @PTHREAD_LIBS@                 \
+    @TN5250_LIBS@
+

src/protocols/tn5250/argv.c

@@ -0,0 +1,196 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "argv.h"
+#include "tn5250.h"
+#include "terminal/terminal.h"
+
+#include <guacamole/protocol.h>
+#include <guacamole/socket.h>
+#include <guacamole/user.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ * All tn5250 connection settings which may be updated by unprivileged users
+ * through "argv" streams.
+ */
+typedef enum guac_tn5250_argv_setting {
+
+    /**
+     * The color scheme of the terminal.
+     */
+    GUAC_TN5250_ARGV_SETTING_COLOR_SCHEME,
+
+    /**
+     * The name of the font family used by the terminal.
+     */
+    GUAC_TN5250_ARGV_SETTING_FONT_NAME,
+
+    /**
+     * The size of the font used by the terminal, in points.
+     */
+    GUAC_TN5250_ARGV_SETTING_FONT_SIZE
+
+} guac_tn5250_argv_setting;
+
+/**
+ * The value or current status of a connection parameter received over an
+ * "argv" stream.
+ */
+typedef struct guac_tn5250_argv {
+
+    /**
+     * The specific setting being updated.
+     */
+    guac_tn5250_argv_setting setting;
+
+    /**
+     * Buffer space for containing the received argument value.
+     */
+    char buffer[GUAC_TN5250_ARGV_MAX_LENGTH];
+
+    /**
+     * The number of bytes received so far.
+     */
+    int length;
+
+} guac_tn5250_argv;
+
+/**
+ * Handler for "blob" instructions which appends the data from received blobs
+ * to the end of the in-progress argument value buffer.
+ *
+ * @see guac_user_blob_handler
+ */
+static int guac_tn5250_argv_blob_handler(guac_user* user,
+        guac_stream* stream, void* data, int length) {
+
+    guac_tn5250_argv* argv = (guac_tn5250_argv*) stream->data;
+
+    /* Calculate buffer size remaining, including space for null terminator,
+     * adjusting received length accordingly */
+    int remaining = sizeof(argv->buffer) - argv->length - 1;
+    if (length > remaining)
+        length = remaining;
+
+    /* Append received data to end of buffer */
+    memcpy(argv->buffer + argv->length, data, length);
+    argv->length += length;
+
+    return 0;
+
+}
+
+/**
+ * Handler for "end" instructions which applies the changes specified by the
+ * argument value buffer associated with the stream.
+ *
+ * @see guac_user_end_handler
+ */
+static int guac_tn5250_argv_end_handler(guac_user* user,
+        guac_stream* stream) {
+
+    int size;
+
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_terminal* terminal = tn5250_client->term;
+
+    /* Append null terminator to value */
+    guac_tn5250_argv* argv = (guac_tn5250_argv*) stream->data;
+    argv->buffer[argv->length] = '\0';
+
+    /* Apply changes to chosen setting */
+    switch (argv->setting) {
+
+        /* Update color scheme */
+        case GUAC_TN5250_ARGV_SETTING_COLOR_SCHEME:
+            guac_terminal_apply_color_scheme(terminal, argv->buffer);
+            break;
+
+        /* Update font name */
+        case GUAC_TN5250_ARGV_SETTING_FONT_NAME:
+            guac_terminal_apply_font(terminal, argv->buffer, -1, 0);
+            break;
+
+        /* Update font size */
+        case GUAC_TN5250_ARGV_SETTING_FONT_SIZE:
+
+            /* Update only if font size is sane */
+            size = atoi(argv->buffer);
+            if (size > 0) {
+                guac_terminal_apply_font(terminal, NULL, size,
+                        tn5250_client->settings->resolution);
+            }
+
+            break;
+
+    }
+
+    /* Update terminal window size if connected */
+    if (tn5250_client->tn5250 != NULL && tn5250_client->naws_enabled)
+        guac_tn5250_send_naws(tn5250_client->tn5250, terminal->term_width,
+                terminal->term_height);
+
+    free(argv);
+    return 0;
+
+}
+
+int guac_tn5250_argv_handler(guac_user* user, guac_stream* stream,
+        char* mimetype, char* name) {
+
+    guac_tn5250_argv_setting setting;
+
+    /* Allow users to update the color scheme and font details */
+    if (strcmp(name, "color-scheme") == 0)
+        setting = GUAC_TN5250_ARGV_SETTING_COLOR_SCHEME;
+    else if (strcmp(name, "font-name") == 0)
+        setting = GUAC_TN5250_ARGV_SETTING_FONT_NAME;
+    else if (strcmp(name, "font-size") == 0)
+        setting = GUAC_TN5250_ARGV_SETTING_FONT_SIZE;
+
+    /* No other connection parameters may be updated */
+    else {
+        guac_protocol_send_ack(user->socket, stream, "Not allowed.",
+                GUAC_PROTOCOL_STATUS_CLIENT_FORBIDDEN);
+        guac_socket_flush(user->socket);
+        return 0;
+    }
+
+    guac_tn5250_argv* argv = malloc(sizeof(guac_tn5250_argv));
+    argv->setting = setting;
+    argv->length = 0;
+
+    /* Prepare stream to receive argument value */
+    stream->blob_handler = guac_tn5250_argv_blob_handler;
+    stream->end_handler = guac_tn5250_argv_end_handler;
+    stream->data = argv;
+
+    /* Signal stream is ready */
+    guac_protocol_send_ack(user->socket, stream, "Ready for updated "
+            "parameter.", GUAC_PROTOCOL_STATUS_SUCCESS);
+    guac_socket_flush(user->socket);
+    return 0;
+
+}
+

src/protocols/tn5250/argv.h

@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+
+#ifndef GUAC_TN5250_ARGV_H
+#define GUAC_TN5250_ARGV_H
+
+#include "config.h"
+
+#include <guacamole/user.h>
+
+/**
+ * The maximum number of bytes to allow for any argument value received via an
+ * argv stream, including null terminator.
+ */
+#define GUAC_TN5250_ARGV_MAX_LENGTH 16384
+
+/**
+ * Handles an incoming stream from a Guacamole "argv" instruction, updating the
+ * given connection parameter if that parameter is allowed to be updated.
+ */
+guac_user_argv_handler guac_tn5250_argv_handler;
+
+#endif
+

src/protocols/tn5250/client.c

@@ -0,0 +1,100 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "client.h"
+#include "common/recording.h"
+#include "settings.h"
+#include "tn5250.h"
+#include "terminal/terminal.h"
+#include "user.h"
+
+#include <langinfo.h>
+#include <locale.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <guacamole/client.h>
+
+int guac_client_init(guac_client* client) {
+
+    /* Set client args */
+    client->args = GUAC_TN5250_CLIENT_ARGS;
+
+    /* Allocate client instance data */
+    guac_tn5250_client* tn5250_client = calloc(1, sizeof(guac_tn5250_client));
+    client->data = tn5250_client;
+
+    /* Init clipboard */
+    tn5250_client->clipboard = guac_common_clipboard_alloc(GUAC_TN5250_CLIPBOARD_MAX_LENGTH);
+
+    /* Init tn5250 client */
+    tn5250_client->socket_fd = -1;
+    tn5250_client->naws_enabled = 0;
+    tn5250_client->echo_enabled = 1;
+
+    /* Set handlers */
+    client->join_handler = guac_tn5250_user_join_handler;
+    client->free_handler = guac_tn5250_client_free_handler;
+
+    /* Set locale and warn if not UTF-8 */
+    setlocale(LC_CTYPE, "");
+    if (strcmp(nl_langinfo(CODESET), "UTF-8") != 0) {
+        guac_client_log(client, GUAC_LOG_INFO,
+                "Current locale does not use UTF-8. Some characters may "
+                "not render correctly.");
+    }
+
+    /* Success */
+    return 0;
+
+}
+
+int guac_tn5250_client_free_handler(guac_client* client) {
+
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+
+    /* Close tn5250 connection */
+    if (tn5250_client->socket_fd != -1)
+        close(tn5250_client->socket_fd);
+
+    /* Clean up recording, if in progress */
+    if (tn5250_client->recording != NULL)
+        guac_common_recording_free(tn5250_client->recording);
+
+    /* Kill terminal */
+    guac_terminal_free(tn5250_client->term);
+
+    /* Wait for and free tn5250 session, if connected */
+    if (tn5250_client->telnet != NULL) {
+        pthread_join(tn5250_client->client_thread, NULL);
+        telnet_free(tn5250_client->telnet);
+    }
+
+    /* Free settings */
+    if (tn5250_client->settings != NULL)
+        guac_tn5250_settings_free(tn5250_client->settings);
+
+    guac_common_clipboard_free(tn5250_client->clipboard);
+    free(tn5250_client);
+    return 0;
+
+}
+

src/protocols/tn5250/client.h

@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TN5250_CLIENT_H
+#define GUAC_TN5250_CLIENT_H
+
+#include "config.h"
+#include "terminal/terminal.h"
+
+#include <pthread.h>
+#include <regex.h>
+#include <sys/types.h>
+
+#include <libtelnet.h>
+
+/**
+ * The maximum number of bytes to allow within the clipboard.
+ */
+#define GUAC_TN5250_CLIPBOARD_MAX_LENGTH 262144
+
+/**
+ * Free handler. Required by libguac and called when the guac_client is
+ * disconnected and must be cleaned up.
+ */
+guac_client_free_handler guac_tn5250_client_free_handler;
+
+#endif
+

src/protocols/tn5250/clipboard.c

@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "clipboard.h"
+#include "common/clipboard.h"
+#include "tn5250.h"
+#include "terminal/terminal.h"
+
+#include <guacamole/client.h>
+#include <guacamole/stream.h>
+#include <guacamole/user.h>
+
+int guac_tn5250_clipboard_handler(guac_user* user, guac_stream* stream,
+        char* mimetype) {
+
+    /* Clear clipboard and prepare for new data */
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_common_clipboard_reset(tn5250_client->clipboard, mimetype);
+
+    /* Set handlers for clipboard stream */
+    stream->blob_handler = guac_tn5250_clipboard_blob_handler;
+    stream->end_handler = guac_tn5250_clipboard_end_handler;
+
+    return 0;
+}
+
+int guac_tn5250_clipboard_blob_handler(guac_user* user, guac_stream* stream,
+        void* data, int length) {
+
+    /* Append new data */
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_common_clipboard_append(tn5250_client->clipboard, data, length);
+
+    return 0;
+}
+
+int guac_tn5250_clipboard_end_handler(guac_user* user, guac_stream* stream) {
+
+    /* Nothing to do - clipboard is implemented within client */
+
+    return 0;
+}
+

src/protocols/tn5250/clipboard.h

@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TN5250_CLIPBOARD_H
+#define GUAC_TN5250_CLIPBOARD_H
+
+#include "config.h"
+
+#include <guacamole/user.h>
+
+/**
+ * Handler for inbound clipboard streams.
+ */
+guac_user_clipboard_handler guac_tn5250_clipboard_handler;
+
+/**
+ * Handler for data received along clipboard streams.
+ */
+guac_user_blob_handler guac_tn5250_clipboard_blob_handler;
+
+/**
+ * Handler for end-of-stream related to clipboard.
+ */
+guac_user_end_handler guac_tn5250_clipboard_end_handler;
+
+#endif
+

src/protocols/tn5250/input.c

@@ -0,0 +1,116 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "common/recording.h"
+#include "input.h"
+#include "terminal/terminal.h"
+#include "tn5250.h"
+
+#include <guacamole/client.h>
+#include <guacamole/user.h>
+#include <libtelnet.h>
+
+#include <regex.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+int guac_tn5250_user_mouse_handler(guac_user* user, int x, int y, int mask) {
+
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_tn5250_settings* settings = tn5250_client->settings;
+    guac_terminal* term = tn5250_client->term;
+
+    /* Skip if terminal not yet ready */
+    if (term == NULL)
+        return 0;
+
+    /* Report mouse position within recording */
+    if (tn5250_client->recording != NULL)
+        guac_common_recording_report_mouse(tn5250_client->recording, x, y,
+                mask);
+
+    /* Send mouse if not searching for password or username */
+    if (settings->password_regex == NULL && settings->username_regex == NULL)
+        guac_terminal_send_mouse(term, user, x, y, mask);
+
+    return 0;
+
+}
+
+int guac_tn5250_user_key_handler(guac_user* user, int keysym, int pressed) {
+
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_tn5250_settings* settings = tn5250_client->settings;
+    guac_terminal* term = tn5250_client->term;
+
+    /* Report key state within recording */
+    if (tn5250_client->recording != NULL)
+        guac_common_recording_report_key(tn5250_client->recording,
+                keysym, pressed);
+
+    /* Skip if terminal not yet ready */
+    if (term == NULL)
+        return 0;
+
+    /* Intercept and handle Pause / Break / Ctrl+0 as "IAC BRK" */
+    if (pressed && (
+                keysym == 0xFF13                  /* Pause */
+             || keysym == 0xFF6B                  /* Break */
+             || (term->mod_ctrl && keysym == '0') /* Ctrl + 0 */
+       )) {
+
+        /* Send IAC BRK */
+        telnet_iac(tn5250_client->telnet, TELNET_BREAK);
+
+        return 0;
+    }
+
+    /* Send key */
+    guac_terminal_send_key(term, keysym, pressed);
+
+    return 0;
+
+}
+
+int guac_tn5250_user_size_handler(guac_user* user, int width, int height) {
+
+    /* Get terminal */
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_terminal* terminal = tn5250_client->term;
+
+    /* Skip if terminal not yet ready */
+    if (terminal == NULL)
+        return 0;
+
+    /* Resize terminal */
+    guac_terminal_resize(terminal, width, height);
+
+    /* Update terminal window size if connected */
+    if (tn5250_client->telnet != NULL && tn5250_client->naws_enabled)
+        guac_tn5250_send_naws(tn5250_client->telnet, terminal->term_width,
+                terminal->term_height);
+
+    return 0;
+}
+

src/protocols/tn5250/input.h

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TN5250_INPUT_H
+#define GUAC_TN5250_INPUT_H
+
+#include "config.h"
+
+#include <guacamole/user.h>
+
+/**
+ * Handler for key events. Required by libguac and called whenever key events
+ * are received.
+ */
+guac_user_key_handler guac_tn5250_user_key_handler;
+
+/**
+ * Handler for mouse events. Required by libguac and called whenever mouse
+ * events are received.
+ */
+guac_user_mouse_handler guac_tn5250_user_mouse_handler;
+
+/**
+ * Handler for size events. Required by libguac and called whenever the remote
+ * display (window) is resized.
+ */
+guac_user_size_handler guac_tn5250_user_size_handler;
+
+#endif
+

src/protocols/tn5250/pipe.c

@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "pipe.h"
+#include "tn5250.h"
+#include "terminal/terminal.h"
+
+#include <guacamole/protocol.h>
+#include <guacamole/socket.h>
+#include <guacamole/user.h>
+
+#include <string.h>
+
+int guac_tn5250_pipe_handler(guac_user* user, guac_stream* stream,
+        char* mimetype, char* name) {
+
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+
+    /* Redirect STDIN if pipe has required name */
+    if (strcmp(name, GUAC_TN5250_STDIN_PIPE_NAME) == 0) {
+        guac_terminal_send_stream(tn5250_client->term, user, stream);
+        return 0;
+    }
+
+    /* No other inbound pipe streams are supported */
+    guac_protocol_send_ack(user->socket, stream, "No such input stream.",
+            GUAC_PROTOCOL_STATUS_RESOURCE_NOT_FOUND);
+    guac_socket_flush(user->socket);
+    return 0;
+
+}
+

src/protocols/tn5250/pipe.h

@@ -0,0 +1,42 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+
+#ifndef GUAC_TN5250_PIPE_H
+#define GUAC_TN5250_PIPE_H
+
+#include "config.h"
+
+#include <guacamole/user.h>
+
+/**
+ * The name reserved for the inbound pipe stream which forces the terminal
+ * emulator's STDIN to be received from the pipe.
+ */
+#define GUAC_TN5250_STDIN_PIPE_NAME "STDIN"
+
+/**
+ * Handles an incoming stream from a Guacamole "pipe" instruction. If the pipe
+ * is named "STDIN", the the contents of the pipe stream are redirected to
+ * STDIN of the terminal emulator for as long as the pipe is open.
+ */
+guac_user_pipe_handler guac_tn5250_pipe_handler;
+
+#endif
+

src/protocols/tn5250/settings.c

@@ -0,0 +1,395 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+
+#include "settings.h"
+
+#include <guacamole/user.h>
+
+#include <sys/types.h>
+#include <regex.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+/* Client plugin arguments */
+const char* GUAC_TN5250_CLIENT_ARGS[] = {
+    "hostname",
+    "port",
+    "ssl",
+    "enhanced",
+    "font-name",
+    "font-size",
+    "color-scheme",
+    "typescript-path",
+    "typescript-name",
+    "create-typescript-path",
+    "recording-path",
+    "recording-name",
+    "recording-exclude-output",
+    "recording-exclude-mouse",
+    "recording-include-keys",
+    "create-recording-path",
+    "read-only",
+    "backspace",
+    "terminal-type",
+    "scrollback",
+    "disable-copy",
+    "disable-paste",
+    NULL
+};
+
+enum TN5250_ARGS_IDX {
+    
+    /**
+     * The hostname to connect to. Required.
+     */
+    IDX_HOSTNAME,
+
+    /**
+     * The port to connect to. Optional.
+     */
+    IDX_PORT,
+    
+    /**
+     * Whether or not to use SSL.  Optional.
+     */
+    IDX_SSL,
+    
+    /**
+     * Whether or not to use RFC2877 enhanced TN5250.  Optional.
+     */
+    IDX_ENHANCED,
+    
+    /**
+     * The name of the font to use within the terminal.
+     */
+    IDX_FONT_NAME,
+
+    /**
+     * The size of the font to use within the terminal, in points.
+     */
+    IDX_FONT_SIZE,
+
+    /**
+     * The color scheme to use, as a series of semicolon-separated color-value
+     * pairs: "background: <color>", "foreground: <color>", or
+     * "color<n>: <color>", where <n> is a number from 0 to 255, and <color> is
+     * "color<n>" or an X11 color code (e.g. "aqua" or "rgb:12/34/56").
+     * The color scheme can also be one of the special values: "black-white",
+     * "white-black", "gray-black", or "green-black".
+     */
+    IDX_COLOR_SCHEME,
+
+    /**
+     * The full absolute path to the directory in which typescripts should be
+     * written.
+     */
+    IDX_TYPESCRIPT_PATH,
+
+    /**
+     * The name that should be given to typescripts which are written in the
+     * given path. Each typescript will consist of two files: "NAME" and
+     * "NAME.timing".
+     */
+    IDX_TYPESCRIPT_NAME,
+
+    /**
+     * Whether the specified typescript path should automatically be created
+     * if it does not yet exist.
+     */
+    IDX_CREATE_TYPESCRIPT_PATH,
+
+    /**
+     * The full absolute path to the directory in which screen recordings
+     * should be written.
+     */
+    IDX_RECORDING_PATH,
+
+    /**
+     * The name that should be given to screen recordings which are written in
+     * the given path.
+     */
+    IDX_RECORDING_NAME,
+
+    /**
+     * Whether output which is broadcast to each connected client (graphics,
+     * streams, etc.) should NOT be included in the session recording. Output
+     * is included by default, as it is necessary for any recording which must
+     * later be viewable as video.
+     */
+    IDX_RECORDING_EXCLUDE_OUTPUT,
+
+    /**
+     * Whether changes to mouse state, such as position and buttons pressed or
+     * released, should NOT be included in the session recording. Mouse state
+     * is included by default, as it is necessary for the mouse cursor to be
+     * rendered in any resulting video.
+     */
+    IDX_RECORDING_EXCLUDE_MOUSE,
+
+    /**
+     * Whether keys pressed and released should be included in the session
+     * recording. Key events are NOT included by default within the recording,
+     * as doing so has privacy and security implications.  Including key events
+     * may be necessary in certain auditing contexts, but should only be done
+     * with caution. Key events can easily contain sensitive information, such
+     * as passwords, credit card numbers, etc.
+     */
+    IDX_RECORDING_INCLUDE_KEYS,
+
+    /**
+     * Whether the specified screen recording path should automatically be
+     * created if it does not yet exist.
+     */
+    IDX_CREATE_RECORDING_PATH,
+
+    /**
+     * "true" if this connection should be read-only (user input should be
+     * dropped), "false" or blank otherwise.
+     */
+    IDX_READ_ONLY,
+
+    /**
+     * ASCII code, as an integer to use for the backspace key, or 127
+     * if not specified.
+     */
+    IDX_BACKSPACE,
+
+    /**
+     * The terminal emulator type that is passed to the remote system (e.g.
+     * "xterm" or "xterm-256color"). "linux" is used if unspecified.
+     */
+    IDX_TERMINAL_TYPE,
+
+    /**
+     * The maximum size of the scrollback buffer in rows.
+     */
+    IDX_SCROLLBACK,
+
+    /**
+     * Whether outbound clipboard access should be blocked. If set to "true",
+     * it will not be possible to copy data from the terminal to the client
+     * using the clipboard. By default, clipboard access is not blocked.
+     */
+    IDX_DISABLE_COPY,
+
+    /**
+     * Whether inbound clipboard access should be blocked. If set to "true", it
+     * will not be possible to paste data from the client to the terminal using
+     * the clipboard. By default, clipboard access is not blocked.
+     */
+    IDX_DISABLE_PASTE,
+
+    TN5250_ARGS_COUNT
+};
+
+guac_tn5250_settings* guac_tn5250_parse_args(guac_user* user,
+        int argc, const char** argv) {
+
+    /* Validate arg count */
+    if (argc != TN5250_ARGS_COUNT) {
+        guac_user_log(user, GUAC_LOG_WARNING, "Incorrect number of connection "
+                "parameters provided: expected %i, got %i.",
+                TN5250_ARGS_COUNT, argc);
+        return NULL;
+    }
+
+    guac_tn5250_settings* settings = calloc(1, sizeof(guac_tn5250_settings));
+
+    /* Read hostname */
+    settings->hostname =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_HOSTNAME, "");
+
+    /* Read-only mode */
+    settings->read_only =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_READ_ONLY, false);
+
+    /* Read maximum scrollback size */
+    settings->max_scrollback =
+        guac_user_parse_args_int(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_SCROLLBACK, GUAC_TN5250_DEFAULT_MAX_SCROLLBACK);
+
+    /* Read font name */
+    settings->font_name =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_FONT_NAME, GUAC_TN5250_DEFAULT_FONT_NAME);
+
+    /* Read font size */
+    settings->font_size =
+        guac_user_parse_args_int(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_FONT_SIZE, GUAC_TN5250_DEFAULT_FONT_SIZE);
+
+    /* Copy requested color scheme */
+    settings->color_scheme =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_COLOR_SCHEME, "");
+
+    /* Pull width/height/resolution directly from user */
+    settings->width      = user->info.optimal_width;
+    settings->height     = user->info.optimal_height;
+    settings->resolution = user->info.optimal_resolution;
+
+    /* Read SSL */
+    settings->ssl =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_SSL, false);
+    
+    int defualt_port = GUAC_TN5250_DEFAULT_PORT;
+    
+    if (settings->ssl)
+        default_port = GUAC_TN5250_DEFAULT_SSL_PORT;
+    
+    /* Read port */
+    settings->port =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_PORT, defualt_port);
+    
+    /* Enhanced mode */
+    settings->enhanced =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_ENHANCED, false);
+
+    /* Read typescript path */
+    settings->typescript_path =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_TYPESCRIPT_PATH, NULL);
+
+    /* Read typescript name */
+    settings->typescript_name =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_TYPESCRIPT_NAME, GUAC_TN5250_DEFAULT_TYPESCRIPT_NAME);
+
+    /* Parse path creation flag */
+    settings->create_typescript_path =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_CREATE_TYPESCRIPT_PATH, false);
+
+    /* Read recording path */
+    settings->recording_path =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_RECORDING_PATH, NULL);
+
+    /* Read recording name */
+    settings->recording_name =
+        guac_user_parse_args_string(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_RECORDING_NAME, GUAC_TN5250_DEFAULT_RECORDING_NAME);
+
+    /* Parse output exclusion flag */
+    settings->recording_exclude_output =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_RECORDING_EXCLUDE_OUTPUT, false);
+
+    /* Parse mouse exclusion flag */
+    settings->recording_exclude_mouse =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_RECORDING_EXCLUDE_MOUSE, false);
+
+    /* Parse key event inclusion flag */
+    settings->recording_include_keys =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_RECORDING_INCLUDE_KEYS, false);
+
+    /* Parse path creation flag */
+    settings->create_recording_path =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_CREATE_RECORDING_PATH, false);
+
+    /* Parse backspace key code */
+    settings->backspace =
+        guac_user_parse_args_int(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_BACKSPACE, 127);
+
+    /* Read terminal emulator type. */
+    char* terminal_type = guac_user_parse_args_string(user,
+            GUAC_TN5250_CLIENT_ARGS, argv, IDX_TERMINAL_TYPE, "5251-11");
+    
+    if (strcmp(terminal_type, "3179-2") == 0)
+        settings->terminal_type = IBM_3179_2;
+    else if (strcmp(terminal_type, "3180-2") == 0)
+        settings->terminal_type = IBM_3180_2;
+    else if (strcmp(terminal_type, "3196-a1") == 0)
+        settings->terminal_type = IBM_3196_A1;
+    else if (strcmp(terminal_type, "3477-fc") == 0)
+        settings->terminal_type = IBM_3477_FC;
+    else if (strcmp(terminal_type, "3477-fg") == 0)
+        settings->terminal_type = IBM_3477_FG;
+    else if (strcmp(terminal_type, "5251-11") == 0)
+        settings->terminal_type = IBM_5251_11;
+    else if (strcmp(terminal_type, "5291-1") == 0)
+        settings->terminal_type = IBM_5291_1;
+    else if (strcmp(terminal_type, "5292-2") == 0)
+        settings->terminal_type = IBM_5292_2;
+    else if (strcmp(terminal_type, "5555-b01") == 0)
+        settings->terminal_type = IBM_5555_B01;
+    else if (strcmp(terminal_type, "5555-c01") == 0)
+        settings->terminal_type = IBM_5555_C01;
+    else {
+        guac_user_log(user, GUAC_LOG_WARNING,
+                "Invalid terminal type %s, defaulting to 5251-11",
+                terminal_type);
+        settings->terminal_type = IBM_5251_11;
+    }
+    free(terminal_type);
+    
+
+    /* Parse clipboard copy disable flag */
+    settings->disable_copy =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_DISABLE_COPY, false);
+
+    /* Parse clipboard paste disable flag */
+    settings->disable_paste =
+        guac_user_parse_args_boolean(user, GUAC_TN5250_CLIENT_ARGS, argv,
+                IDX_DISABLE_PASTE, false);
+
+    /* Parsing was successful */
+    return settings;
+
+}
+
+void guac_tn5250_settings_free(guac_tn5250_settings* settings) {
+
+    /* Free network connection information */
+    free(settings->hostname);
+    free(settings->port);
+
+    /* Free display preferences */
+    free(settings->font_name);
+    free(settings->color_scheme);
+
+    /* Free typescript settings */
+    free(settings->typescript_name);
+    free(settings->typescript_path);
+
+    /* Free screen recording settings */
+    free(settings->recording_name);
+    free(settings->recording_path);
+
+    /* Free terminal emulator type. */
+    free(settings->terminal_type);
+
+    /* Free overall structure */
+    free(settings);
+
+}
+

src/protocols/tn5250/settings.h

@@ -0,0 +1,376 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TN5250_SETTINGS_H
+#define GUAC_TN5250_SETTINGS_H
+
+#include "config.h"
+
+#include <guacamole/user.h>
+
+#include <sys/types.h>
+#include <regex.h>
+#include <stdbool.h>
+
+/**
+ * The name of the font to use for the terminal if no name is specified.
+ */
+#define GUAC_TN5250_DEFAULT_FONT_NAME "monospace" 
+
+/**
+ * The size of the font to use for the terminal if no font size is specified,
+ * in points.
+ */
+#define GUAC_TN5250_DEFAULT_FONT_SIZE 12
+
+/**
+ * The port to connect to when initiating a 5250 telnet connection, if no other
+ * port is specified.
+ */
+#define GUAC_TN5250_DEFAULT_PORT "23"
+
+/**
+ * The port to connect to when initiating a 5250 telnet connection over SSL,
+ * if no other port is specified.
+ */
+#define GUAC_TN5250_DEFAULT_SSL_PORT "992"
+
+/**
+ * The filename to use for the typescript, if not specified.
+ */
+#define GUAC_TN5250_DEFAULT_TYPESCRIPT_NAME "typescript" 
+
+/**
+ * The filename to use for the screen recording, if not specified.
+ */
+#define GUAC_TN5250_DEFAULT_RECORDING_NAME "recording"
+
+/**
+ * The default maximum scrollback size in rows.
+ */
+#define GUAC_TN5250_DEFAULT_MAX_SCROLLBACK 1000
+
+/**
+ * The available terminal types for TN5250 connections.  These are defined
+ * in RFC-1205, Section 2.
+ */
+typedef enum guac_tn5250_terminal_types {
+    
+    /**
+     * IBM-3179-2, 24 x 80 color display
+     */
+    IBM_3179_2,
+
+    /**
+     * IBM-3180-2, 27 x 132 monochrome display
+     */
+    IBM_3180_2,
+
+    /**
+     * IBM-3196-A1, 24 x 80 monochrome display
+     */
+    IBM_3196_A1,
+
+    /**
+     * IBM-3477-FC, 27 x 132 color display
+     */
+    IBM_3477_FC,
+
+    /**
+     * IBM-3477-FG, 27 x 132 monochrome display
+     */
+    IBM_3477_FG,
+
+    /**
+     * IBM-5251-11, 24 x 80 monochrome display
+     */
+    IBM_5251_11,
+
+    /**
+     * IBM-5291-1, 24 x 80 monochrome display
+     */
+    IBM_5291_1,
+
+    /**
+     * IBM-5292-2, 24 x 80 color display
+     */
+    IBM_5292_2,
+
+    /**
+     * IBM-5555-B01, 24 x 80 Double-Byte Character Set (DBCS)
+     */
+    IBM_5555_B01,
+
+    /**
+     * IBM-5555-C01, 24 x 80 Double-Byte Character Set color display
+     */
+    IBM_5555_C01
+    
+} guac_tn5250_terminal_type;
+
+/**
+ * Data structure to store all of the characteristics of various types of
+ * 5250-compatible terminals.
+ */
+typedef struct __guac_tn5250_terminal_params {
+    
+    /**
+     * The type of terminal, as defined in RFC-1205
+     */
+    char* terminal;
+    
+    /**
+     * The number of rows in the terminal
+     */
+    int rows;
+    
+    /**
+     * The number of columns in the terminal
+     */
+    int cols;
+    
+    /**
+     * True if the terminal supports color, false if only monochrome.
+     */
+    bool color;
+    
+} __guac_tn5250_terminal_params;
+
+/**
+ * An array of all of the possible terminal types, including the ENUM value,
+ * the height (in rows) and width (in columns), and whether or not the terminal
+ * supports color (true if color, false if monochrome).
+ */
+__guac_tn5250_terminal_params __guac_tn5250_terminals[] = {
+    {"IBM_3179_2",   24, 80,  true },
+    {"IBM_3180_2",   27, 132, false},
+    {"IBM_3196_A1",  24, 80,  false},
+    {"IBM_3477_FC",  27, 132, true },
+    {"IBM_3477_FG",  27, 132, false},
+    {"IBM_5251_11",  24, 80,  false},
+    {"IBM_5291_1",   24, 80,  false},
+    {"IBM_5292_2",   24, 80,  true },
+    {"IBM_5555_B01", 24, 80,  false},
+    {"IBM_5555_C01", 24, 80,  true },
+    {NULL,         -1, -1,  false}
+};
+
+/**
+ * Settings for the TN5250 connection. The values for this structure are parsed
+ * from the arguments given during the Guacamole protocol handshake using the
+ * guac_tn5250_parse_args() function.
+ */
+typedef struct guac_tn5250_settings {
+
+    /**
+     * The hostname of the TN5250 server to connect to.
+     */
+    char* hostname;
+
+    /**
+     * The port of the TN5250 server to connect to.
+     */
+    char* port;
+    
+    /**
+     * Whether or not to use SSL.
+     */
+    bool ssl;
+    
+    /**
+     * Whether or not to use enhanced TN5250 mode (RFC2877)
+     */
+    bool enhanced;
+
+    /**
+     * Whether this connection is read-only, and user input should be dropped.
+     */
+    bool read_only;
+
+    /**
+     * The maximum size of the scrollback buffer in rows.
+     */
+    int max_scrollback;
+
+    /**
+     * The name of the font to use for display rendering.
+     */
+    char* font_name;
+
+    /**
+     * The size of the font to use, in points.
+     */
+    int font_size;
+
+    /**
+     * The name of the color scheme to use.
+     */
+    char* color_scheme; 
+
+    /**
+     * The desired width of the terminal display, in pixels.
+     */
+    int width;
+
+    /**
+     * The desired height of the terminal display, in pixels.
+     */
+    int height;
+
+    /**
+     * The desired screen resolution, in DPI.
+     */
+    int resolution;
+
+    /**
+     * Whether outbound clipboard access should be blocked. If set, it will not
+     * be possible to copy data from the terminal to the client using the
+     * clipboard.
+     */
+    bool disable_copy;
+
+    /**
+     * Whether inbound clipboard access should be blocked. If set, it will not
+     * be possible to paste data from the client to the terminal using the
+     * clipboard.
+     */
+    bool disable_paste;
+
+    /**
+     * The path in which the typescript should be saved, if enabled. If no
+     * typescript should be saved, this will be NULL.
+     */
+    char* typescript_path;
+
+    /**
+     * The filename to use for the typescript, if enabled.
+     */
+    char* typescript_name;
+
+    /**
+     * Whether the typescript path should be automatically created if it does
+     * not already exist.
+     */
+    bool create_typescript_path;
+
+    /**
+     * The path in which the screen recording should be saved, if enabled. If
+     * no screen recording should be saved, this will be NULL.
+     */
+    char* recording_path;
+
+    /**
+     * The filename to use for the screen recording, if enabled.
+     */
+    char* recording_name;
+
+    /**
+     * Whether the screen recording path should be automatically created if it
+     * does not already exist.
+     */
+    bool create_recording_path;
+
+    /**
+     * Whether output which is broadcast to each connected client (graphics,
+     * streams, etc.) should NOT be included in the session recording. Output
+     * is included by default, as it is necessary for any recording which must
+     * later be viewable as video.
+     */
+    bool recording_exclude_output;
+
+    /**
+     * Whether changes to mouse state, such as position and buttons pressed or
+     * released, should NOT be included in the session recording. Mouse state
+     * is included by default, as it is necessary for the mouse cursor to be
+     * rendered in any resulting video.
+     */
+    bool recording_exclude_mouse;
+
+    /**
+     * Whether keys pressed and released should be included in the session
+     * recording. Key events are NOT included by default within the recording,
+     * as doing so has privacy and security implications.  Including key events
+     * may be necessary in certain auditing contexts, but should only be done
+     * with caution. Key events can easily contain sensitive information, such
+     * as passwords, credit card numbers, etc.
+     */
+    bool recording_include_keys;
+
+    /**
+     * The ASCII code, as an integer, that the 5250 client will use when the
+     * backspace key is pressed.  By default, this is 127, ASCII delete, if
+     * not specified in the client settings.
+     */
+    int backspace;
+
+    /**
+     * The terminal emulator type that is passed to the remote system.
+     */
+    guac_tn5250_terminal_type terminal_type;
+
+} guac_tn5250_settings;
+
+/**
+ * Parses all given args, storing them in a newly-allocated settings object. If
+ * the args fail to parse, NULL is returned.
+ *
+ * @param user
+ *     The user who submitted the given arguments while joining the
+ *     connection.
+ *
+ * @param argc
+ *     The number of arguments within the argv array.
+ *
+ * @param argv
+ *     The values of all arguments provided by the user.
+ *
+ * @return
+ *     A newly-allocated settings object which must be freed with
+ *     guac_tn5250_settings_free() when no longer needed. If the arguments fail
+ *     to parse, NULL is returned.
+ */
+guac_tn5250_settings* guac_tn5250_parse_args(guac_user* user,
+        int argc, const char** argv);
+
+/**
+ * Frees the regex pointed to by the given pointer, assigning the value NULL to
+ * that pointer once the regex is freed. If the pointer already contains NULL,
+ * this function has no effect.
+ *
+ * @param regex
+ *     The address of the pointer to the regex that should be freed.
+ */
+void guac_tn5250_regex_free(regex_t** regex);
+
+/**
+ * Frees the given guac_tn5250_settings object, having been previously
+ * allocated via guac_tn5250_parse_args().
+ *
+ * @param settings
+ *     The settings object to free.
+ */
+void guac_tn5250_settings_free(guac_tn5250_settings* settings);
+
+/**
+ * NULL-terminated array of accepted client args.
+ */
+extern const char* GUAC_TN5250_CLIENT_ARGS[];
+
+#endif
+

src/protocols/tn5250/sna.h

@@ -0,0 +1,178 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+/* 
+ * File:   sna.h
+ * Author: nick_couchman
+ *
+ * Created on August 4, 2019, 1:43 PM
+ */
+
+#ifndef GUAC_SNA_H
+#define GUAC_SNA_H
+
+/**
+ * This is the packet header that defines traffic on the TN5250 link as
+ * SNA traffic.  It will be present on traffic coming from the mainframe,
+ * and should also be sent for any SNA-specific traffic to the mainframe.
+ */
+#define SNA_PACKET_HEADER 0x12a0
+
+/**
+ * This is a constant header on all SNA packets.
+ */
+#define SNA_VAR_HEADER 0x04
+
+/**
+ * Operational codes as defined in RFC1207.
+ * 
+ * No operation.
+ */
+#define OPCODE_NOOP 0x00
+
+/**
+ * Invite operation, sent by server to allow client to talk.
+ */
+#define OPCODE_INVITE 0x01
+
+/**
+ * Output only
+ */
+#define OPCODE_OUTPUT 0x02
+
+/**
+ * Put/get operation
+ */
+#define OPCODE_PUT_GET 0x03
+
+/**
+ * Save screen
+ */
+#define OPCODE_SAVE_SCREEN 0x04
+
+/**
+ * Restore screen
+ */
+#define OPCODE_RESTORE_SCREEN 0x05
+
+/**
+ * Read immediate
+ */
+#define OPCODE_READ_IMMEIDATE 0x06
+
+/**
+ * Read screen
+ */
+#define OPCODE_READ_SCREEN 0x08
+
+/**
+ * Cancel invite
+ */
+#define OPCODE_CANCEL_INVITE 0x0a
+
+/**
+ * Message light on
+ */
+#define OPCODE_MSG_ON 0x0b
+
+/**
+ * Message light off
+ */
+#define OPCODE_MSG_OFF 0x0c
+
+/**
+ * A 16-bit set of flags, as defined in RFC1205, Section 3, for TN5250-specific
+ * data transfer.
+ */
+struct sna_flags {
+    
+    /**
+     * Indicates data stream output error.
+     */
+    unsigned int ERR : 1;
+    
+    /**
+     * 5250 Attention Key has been pressed.
+     */
+    unsigned int ATN : 1;
+    
+    /**
+     * Reserved/unused.
+     */
+    unsigned int : 3;
+    
+    /**
+     * System Request key was pressed.
+     */
+    unsigned int SRQ : 1;
+    
+    /**
+     * Test Request key was pressed.
+     */
+    unsigned int TRQ : 1;
+    
+    /**
+     * Help in Error State function - error code will follow header in data.
+     */
+    unsigned int HLP : 1;
+    
+    /**
+     * Final 8 bits are reserved/unused.
+     */
+    unsigned int : 8;
+    
+} sna_flags;
+
+/**
+ * Defines the structure of a TN5250 (SNA over Telnet) packet, including
+ * the fields and the length of each field, as described in RFC1205.
+ */
+struct sna_packet {
+    
+    /**
+     * The length of the packet.
+     */
+    unsigned int len : 16;
+    
+    /**
+     * The SNA header marker, 0x12a0
+     */
+    unsigned int sna_header : 16;
+    
+    /**
+     * Reserved portion, should be zeroes.
+     */
+    unsigned int reserved : 16;
+    
+    /**
+     * The variable header length, always 0x04.
+     */
+    unsigned int varlen : 8;
+    
+    /**
+     * SNA flags.
+     */
+    unsigned int sna_flags : 16;
+    
+    /**
+     * The opcode.
+     */
+    unsigned int opcode : 8;
+    
+    /**
+     * Any data sent in the packet.
+     */
+    void* sna_data;
+    
+    /**
+     * IAC and EOR marker.
+     */
+    unsigned int sna_end : 16;
+    
+} sna_packet;
+
+#endif /* SNA_H */
+

src/protocols/tn5250/tn5250.c

@@ -0,0 +1,561 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+#include "common/recording.h"
+#include "tn5250.h"
+#include "terminal/terminal.h"
+
+#include <guacamole/client.h>
+#include <guacamole/protocol.h>
+#include <libtelnet.h>
+
+#include <errno.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+/**
+ * Support levels for various telnet options, required for connection
+ * negotiation by telnet_init(), part of libtelnet.  The TN5250 specification
+ * requires at EOR, BINARY, and TTYPE.
+ */
+static const telnet_telopt_t __telnet_options[] = {
+    { TELNET_TELOPT_ECHO,        TELNET_WONT, TELNET_DO   },
+    { TELNET_TELOPT_TTYPE,       TELNET_WILL, TELNET_DO   },
+    { TELNET_TELOPT_COMPRESS2,   TELNET_WONT, TELNET_DO   },
+    { TELNET_TELOPT_MSSP,        TELNET_WONT, TELNET_DO   },
+    { TELNET_TELOPT_NAWS,        TELNET_WONT, TELNET_DONT },
+    { TELNET_TELOPT_NEW_ENVIRON, TELNET_WILL, TELNET_DONT },
+    { TELNET_TELOPT_EOR,         TELNET_WILL, TELNET_DO   },
+    { TELNET_TELOPT_BINARY,      TELNET_WILL, TELNET_DO   },
+    { -1, 0, 0 }
+};
+
+/**
+ * ***Should be abstracted to common telnet support.***
+ * Write the entire buffer given to the specified file descriptor, retrying
+ * the write automatically if necessary. This function will return a value
+ * not equal to the buffer's size iff an error occurs which prevents all
+ * future writes.
+ *
+ * @param fd The file descriptor to write to.
+ * @param buffer The buffer to write.
+ * @param size The number of bytes from the buffer to write.
+ */
+static int __guac_telnet_write_all(int fd, const char* buffer, int size) {
+
+    int remaining = size;
+    while (remaining > 0) {
+
+        /* Attempt to write data */
+        int ret_val = write(fd, buffer, remaining);
+        if (ret_val <= 0)
+            return -1;
+
+        /* If successful, continue with what data remains (if any) */
+        remaining -= ret_val;
+        buffer += ret_val;
+
+    }
+
+    return size;
+
+}
+
+/**
+ * Event handler, as defined by libtelnet. This function is passed to
+ * telnet_init() and will be called for every event fired by libtelnet,
+ * including feature enable/disable and receipt/transmission of data.
+ */
+static void __guac_tn5250_event_handler(telnet_t* telnet, telnet_event_t* event, void* data) {
+
+    guac_client* client = (guac_client*) data;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_tn5250_settings* settings = tn5250_client->settings;
+
+    switch (event->type) {
+
+        /* Terminal output received */
+        case TELNET_EV_DATA:
+            __guac_tn5250_recv_sna_packet(client, event);
+            // guac_terminal_write(tn5250_client->term, event->data.buffer, event->data.size);
+            break;
+
+        /* Data destined for remote end */
+        case TELNET_EV_SEND:
+            if (__guac_tn5250_send_sna_packet(telnet, event))
+                guac_client_stop(client);
+            if (__guac_tn5250_write_all(tn5250_client->socket_fd, event->data.buffer, event->data.size)
+                    != event->data.size)
+                guac_client_stop(client);
+            break;
+
+        /* Remote feature enabled */
+        case TELNET_EV_WILL:
+            guac_client_log(client, GUAC_LOG_DEBUG, "Received TELNET_EV_WILL "
+                    "for option %d", event->neg.telopt);
+            if (event->neg.telopt == TELNET_TELOPT_ECHO)
+                tn5250_client->echo_enabled = 0; /* Disable local echo, as remote will echo */
+            break;
+
+        /* Remote feature disabled */
+        case TELNET_EV_WONT:
+            guac_client_log(client, GUAC_LOG_DEBUG, "Received TELNET_EV_WONT "
+                    "for option %d", event->neg.telopt);
+            if (event->neg.telopt == TELNET_TELOPT_ECHO)
+                tn5250_client->echo_enabled = 1; /* Enable local echo, as remote won't echo */
+            break;
+
+        /* Local feature enable */
+        case TELNET_EV_DO:
+            guac_client_log(client, GUAC_LOG_DEBUG, "Received TELNET_EV_DO "
+                    "for option %d", event->neg.telopt);
+            break;
+
+        /* Terminal type request */
+        case TELNET_EV_TTYPE:
+            guac_client_log(client, GUAC_LOG_DEBUG, "Received TELNET_EV_TTYPE "
+                    "for command %d", event->ttype.cmd);
+            if (event->ttype.cmd == TELNET_TTYPE_SEND)
+                tn5250_ttype_is(tn5250_client->telnet, __guac_tn5250_terminals[settings->terminal_type].terminal);
+            break;
+
+        /* Environment request */
+        case TELNET_EV_ENVIRON:
+
+            guac_client_log(client, GUAC_LOG_DEBUG, "Received TELNET_EV_ENVIRON "
+                    "for size %d", event->environ.size);
+            
+            /* Only send USER if entire environment was requested */
+            if (event->environ.size == 0)
+                guac_tn5250_send_user(telnet, settings->username);
+
+            break;
+
+        /* Connection warnings */
+        case TELNET_EV_WARNING:
+            guac_client_log(client, GUAC_LOG_WARNING, "%s", event->error.msg);
+            break;
+
+        /* Connection errors */
+        case TELNET_EV_ERROR:
+            guac_client_abort(client, GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR,
+                    "Telnet connection closing with error: %s", event->error.msg);
+            break;
+
+        /* Ignore other events */
+        default:
+            break;
+
+    }
+
+}
+
+/**
+ * Input thread, started by the main telnet client thread. This thread
+ * continuously reads from the terminal's STDIN and transfers all read
+ * data to the telnet connection.
+ *
+ * @param data The current guac_client instance.
+ * @return Always NULL.
+ */
+static void* __guac_tn5250_input_thread(void* data) {
+
+    guac_client* client = (guac_client*) data;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+
+    char buffer[8192];
+    int bytes_read;
+
+    /* Write all data read */
+    while ((bytes_read = guac_terminal_read_stdin(tn5250_client->term, buffer, sizeof(buffer))) > 0) {
+        telnet_send(tn5250_client->telnet, buffer, bytes_read);
+        if (tn5250_client->echo_enabled)
+            guac_terminal_write(tn5250_client->term, buffer, bytes_read);
+    }
+
+    return NULL;
+
+}
+
+/**
+ * ***Abstract to common telnet code.***
+ * Connects to the telnet server specified within the data associated
+ * with the given guac_client, which will have been populated by
+ * guac_client_init.
+ *
+ * @return The connected telnet instance, if successful, or NULL if the
+ *         connection fails for any reason.
+ */
+static telnet_t* __guac_tn5250_create_session(guac_client* client) {
+
+    int retval;
+
+    int fd;
+    struct addrinfo* addresses;
+    struct addrinfo* current_address;
+
+    char connected_address[1024];
+    char connected_port[64];
+
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_tn5250_settings* settings = tn5250_client->settings;
+
+    struct addrinfo hints = {
+        .ai_family   = AF_UNSPEC,
+        .ai_socktype = SOCK_STREAM,
+        .ai_protocol = IPPROTO_TCP
+    };
+
+    /* Get socket */
+    fd = socket(AF_INET, SOCK_STREAM, 0);
+
+    /* Get addresses connection */
+    if ((retval = getaddrinfo(settings->hostname, settings->port,
+                    &hints, &addresses))) {
+        guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Error parsing given address or port: %s",
+                gai_strerror(retval));
+        return NULL;
+
+    }
+
+    /* Attempt connection to each address until success */
+    current_address = addresses;
+    while (current_address != NULL) {
+
+        int retval;
+
+        /* Resolve hostname */
+        if ((retval = getnameinfo(current_address->ai_addr,
+                current_address->ai_addrlen,
+                connected_address, sizeof(connected_address),
+                connected_port, sizeof(connected_port),
+                NI_NUMERICHOST | NI_NUMERICSERV)))
+            guac_client_log(client, GUAC_LOG_DEBUG, "Unable to resolve host: %s", gai_strerror(retval));
+
+        /* Connect */
+        if (connect(fd, current_address->ai_addr,
+                        current_address->ai_addrlen) == 0) {
+
+            guac_client_log(client, GUAC_LOG_DEBUG, "Successfully connected to "
+                    "host %s, port %s", connected_address, connected_port);
+
+            /* Done if successful connect */
+            break;
+
+        }
+
+        /* Otherwise log information regarding bind failure */
+        else
+            guac_client_log(client, GUAC_LOG_DEBUG, "Unable to connect to "
+                    "host %s, port %s: %s",
+                    connected_address, connected_port, strerror(errno));
+
+        current_address = current_address->ai_next;
+
+    }
+
+    /* If unable to connect to anything, fail */
+    if (current_address == NULL) {
+        guac_client_abort(client, GUAC_PROTOCOL_STATUS_UPSTREAM_NOT_FOUND,
+                "Unable to connect to any addresses.");
+        return NULL;
+    }
+
+    /* Free addrinfo */
+    freeaddrinfo(addresses);
+
+    /* Open telnet session */
+    telnet_t* telnet = telnet_init(__telnet_options, __guac_telnet_event_handler, 0, client);
+    if (telnet == NULL) {
+        guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Telnet client allocation failed.");
+        return NULL;
+    }
+
+    /* Save file descriptor */
+    tn5250_client->socket_fd = fd;
+
+    return telnet;
+
+}
+
+/**
+ * Sends a 16-bit value over the given telnet connection with the byte order
+ * required by the telnet protocol.
+ *
+ * @param telnet The telnet connection to use.
+ * @param value The value to send.
+ */
+static void __guac_tn5250_send_uint16(telnet_t* telnet, uint16_t value) {
+
+    unsigned char buffer[2];
+    buffer[0] = (value >> 8) & 0xFF;
+    buffer[1] =  value       & 0xFF;
+
+    telnet_send(telnet, (char*) buffer, 2);
+
+}
+
+/**
+ * Sends an 8-bit value over the given telnet connection.
+ *
+ * @param telnet The telnet connection to use.
+ * 
+ * @param value The value to send.
+ */
+static void __guac_tn5250_send_uint8(telnet_t* telnet, uint8_t value) {
+    telnet_send(telnet, (char*) (&value), 1);
+}
+
+void guac_tn5250_send_user(telnet_t* telnet, const char* username) {
+
+    /* IAC SB NEW-ENVIRON IS */
+    telnet_begin_sb(telnet, TELNET_TELOPT_NEW_ENVIRON);
+    __guac_tn5250_send_uint8(telnet, TELNET_ENVIRON_IS);
+
+    /* Only send username if defined */
+    if (username != NULL) {
+
+        /* VAR "USER" */
+        __guac_tn5250_send_uint8(telnet, TELNET_ENVIRON_VAR);
+        telnet_send(telnet, "USER", 4);
+
+        /* VALUE username */
+        __guac_tn5250_send_uint8(telnet, TELNET_ENVIRON_VALUE);
+        telnet_send(telnet, username, strlen(username));
+
+    }
+
+    /* IAC SE */
+    telnet_finish_sb(telnet);
+
+}
+
+/**
+ * Waits for data on the given file descriptor for up to one second. The
+ * return value is identical to that of select(): 0 on timeout, < 0 on
+ * error, and > 0 on success.
+ *
+ * @param socket_fd The file descriptor to wait for.
+ * 
+ * @return A value greater than zero on success, zero on timeout, and
+ *         less than zero on error.
+ */
+static int __guac_tn5250_wait(int socket_fd) {
+
+    /* Build array of file descriptors */
+    struct pollfd fds[] = {{
+        .fd      = socket_fd,
+        .events  = POLLIN,
+        .revents = 0,
+    }};
+
+    /* Wait for one second */
+    return poll(fds, 1, 1000);
+
+}
+
+void* guac_tn5250_client_thread(void* data) {
+
+    guac_client* client = (guac_client*) data;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+    guac_tn5250_settings* settings = tn5250_client->settings;
+
+    pthread_t input_thread;
+    char buffer[8192];
+    int wait_result;
+
+    /* Set up screen recording, if requested */
+    if (settings->recording_path != NULL) {
+        tn5250_client->recording = guac_common_recording_create(client,
+                settings->recording_path,
+                settings->recording_name,
+                settings->create_recording_path,
+                !settings->recording_exclude_output,
+                !settings->recording_exclude_mouse,
+                settings->recording_include_keys);
+    }
+
+    /* Calculate required terminal size based on type. */
+    
+    /* Create terminal */
+    tn5250_client->term = guac_terminal_create(client,
+            tn5250_client->clipboard, settings->disable_copy,
+            settings->max_scrollback, settings->font_name, settings->font_size,
+            settings->resolution, settings->width, settings->height,
+            settings->color_scheme, settings->backspace);
+
+    /* Fail if terminal init failed */
+    if (tn5250_client->term == NULL) {
+        guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
+                "Terminal initialization failed");
+        return NULL;
+    }
+    
+    /* Fix terminal width/height */
+    tn5250_client->term.term_width = __guac_tn5250_terminals[settings->terminal_type].cols;
+    tn5250_client->term.term_height = __guac_tn5250_terminals[settings->terminal_type].rows;
+
+    /* Set up typescript, if requested */
+    if (settings->typescript_path != NULL) {
+        guac_terminal_create_typescript(tn5250_client->term,
+                settings->typescript_path,
+                settings->typescript_name,
+                settings->create_typescript_path);
+    }
+
+    /* Open telnet session */
+    tn5250_client->telnet = __guac_tn5250_create_session(client);
+    if (tn5250_client->telnet == NULL) {
+        /* Already aborted within __guac_tn5250_create_session() */
+        return NULL;
+    }
+
+    /* Logged in */
+    guac_client_log(client, GUAC_LOG_INFO, "TN5250 connection successful.");
+
+    /* Allow terminal to render */
+    guac_terminal_start(tn5250_client->term);
+
+    /* Start input thread */
+    if (pthread_create(&(input_thread), NULL, __guac_tn5250_input_thread, (void*) client)) {
+        guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Unable to start input thread");
+        return NULL;
+    }
+
+    /* While data available, write to terminal */
+    while ((wait_result = __guac_tn5250_wait(tn5250_client->socket_fd)) >= 0) {
+
+        /* Resume waiting of no data available */
+        if (wait_result == 0)
+            continue;
+
+        int bytes_read = read(tn5250_client->socket_fd, buffer, sizeof(buffer));
+        if (bytes_read <= 0)
+            break;
+
+        telnet_recv(tn5250_client->telnet, buffer, bytes_read);
+
+    }
+
+    /* Kill client and Wait for input thread to die */
+    guac_client_stop(client);
+    pthread_join(input_thread, NULL);
+
+    guac_client_log(client, GUAC_LOG_INFO, "TN5250 connection ended.");
+    return NULL;
+
+}
+
+void __guac_tn5250_send_sna_packet(void* data, tn5250_flags flags,
+        unsigned char opcode, char* data) {
+    
+    /**
+     * Things to do, here:
+     * - Put the TN5250 header on
+     * - Set any flags
+     * - Set the Opcode
+     * - Write data
+     * - Write EOR
+     */
+    
+    
+}
+
+void __guac_tn5250_recv_sna_packet(guac_client* client, telnet_event_t* event) {
+    
+    /**
+     * Things to do, here:
+     * - Check for TN5250 header
+     * - Take off flags and process
+     * - Examine Opcode and handle (switch)
+     * - Read data and handle it (while)
+     * - Look for EOR (while)
+     */
+    
+    /* Look for TN5250 header - abort if not found. */
+    
+    /* Grab flags */
+    
+    /* Process Opcode */
+    switch (opcode) {
+        
+        case OPCODE_NOOP:
+            
+            break;
+            
+        case OPCODE_INVITE:
+            
+            break;
+            
+        case OPCODE_OUTPUT:
+            
+            break;
+            
+        case OPCODE_PUT_GET:
+            
+            break;
+            
+        case OPCODE_SAVE_SCREEN:
+            
+            break;
+            
+        case OPCODE_RESTORE_SCREEN:
+            
+            break;
+            
+        case OPCODE_READ_IMMEDIATE:
+            
+            break:
+            
+        case OPCODE_READ_SCREEN:
+            
+            break;
+            
+        case OPCODE_CANCEL_INVITE:
+            
+            break;
+            
+        case OPCODE_MSG_ON:
+            
+            break;
+            
+        case OPCODE_MSG_OFF:
+            
+            break;
+            
+        default:
+            
+    }
+    
+    /* Process data until we get the EOR option */
+    while (packet[i] != TELNET_TELOPT_EOR) {
+        
+    }
+    
+}
+

src/protocols/tn5250/tn5250.h

@@ -0,0 +1,161 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TN5250_H
+#define GUAC_TN5250_H
+
+#include "config.h"
+#include "common/clipboard.h"
+#include "common/recording.h"
+#include "settings.h"
+#include "sna.h"
+#include "terminal/terminal.h"
+
+#include <libtelnet.h>
+
+#include <stdint.h>
+
+/**
+ * Telnet-specific client data.
+ */
+typedef struct guac_tn5250_client {
+
+    /**
+     * TN5250 connection settings.
+     */
+    guac_tn5250_settings* settings;
+
+    /**
+     * The tn5250 client thread.
+     */
+    pthread_t client_thread;
+
+    /**
+     * The file descriptor of the socket connected to the tn5250 server,
+     * or -1 if no connection has been established.
+     */
+    int socket_fd;
+
+    /**
+     * telnet connection, used by the tn5250 client thread.
+     */
+    telnet_t* telnet;
+
+    /**
+     * Whether window size should be sent when the window is resized.
+     */
+    int naws_enabled;
+
+    /**
+     * Whether all user input should be automatically echoed to the
+     * terminal.
+     */
+    int echo_enabled;
+
+    /**
+     * The current clipboard contents.
+     */
+    guac_common_clipboard* clipboard;
+
+    /**
+     * The terminal which will render all output from the tn5250 client.
+     */
+    guac_terminal* term;
+
+    /**
+     * The in-progress session recording, or NULL if no recording is in
+     * progress.
+     */
+    guac_common_recording* recording;
+
+} guac_tn5250_client;
+
+/**
+ * Possible Opcodes that can be sent by the mainframe or the client.
+ */
+unsigned char tn5250_opcodes[] = {
+    OPCODE_NOOP, /* No operation */
+    OPCODE_INVITE, /* Invite */
+    OPCODE_OUTPUT, /* Output only */
+    OPCODE_PUT_GET, /* Put/Get */
+    OPCODE_SAVE_SCREEN, /* Save screen */
+    OPCODE_RESTORE_SCREEN, /* Restore screen */
+    OPCODE_READ_IMMEDIATE, /* Read immediate */
+    0x07, /* Reserved */
+    OPCODE_READ_SCREEN, /* Read screen */
+    0x09, /* Reserved */
+    OPCODE_CANCEL_INVITE, /* Cancel invite */
+    OPCODE_MSG_ON, /* Turn on message light */
+    OPCODE_MSG_OFF, /* Turn off message light */
+    NULL
+} 
+
+/**
+ * Main tn5250 client thread, handling transfer of tn5250 output to STDOUT.
+ * 
+ * @param data
+ *     The client data associated with this thread.
+ */
+void* guac_tn5250_client_thread(void* data);
+
+/**
+ * Sends the given username by setting the remote USER environment variable
+ * using the tn5250 NEW-ENVIRON option.
+ * 
+ * @param telnet
+ *     The telnet connection to send the USER variable to.
+ * 
+ * @param username
+ *     The username to send.
+ */
+void guac_tn5250_send_user(telnet_t* telnet, const char* username);
+
+/**
+ * Sends the given data in TN5250 mode, creating the necessary packet
+ * structure over the telnet connection to talk to the system.
+ * 
+ * @param telnet
+ *     The telnet client sending the packet.
+ * 
+ * @param sna_flags
+ *     Any flags that should be set in the packet.
+ * 
+ * @param opcode
+ *     Any opcode that should be sent to the mainframe.
+ * 
+ * @param data
+ *     Data that should be sent to the mainframe.
+ */
+void __guac_tn5250_send_sna_packet(telnet_t* telnet, sna_flags flags,
+        unsigned char opcode, char* data);
+
+/**
+ * Handles a received SNA packet, processing flags and opcodes, and then writing
+ * any output to the terminal.
+ * 
+ * @param client
+ *     The Guacamole Client that is receiving the packet.
+ * 
+ * @param event
+ *     The Telnet event that is being processed.
+ */
+void __guac_tn5250_recv_sna_packet(guac_client* client, telnet_event_t* event);
+
+#endif
+

src/protocols/tn5250/user.c

@@ -0,0 +1,121 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+
+#include "argv.h"
+#include "clipboard.h"
+#include "input.h"
+#include "pipe.h"
+#include "settings.h"
+#include "tn5250.h"
+#include "terminal/terminal.h"
+#include "user.h"
+
+#include <guacamole/client.h>
+#include <guacamole/socket.h>
+#include <guacamole/user.h>
+
+#include <pthread.h>
+#include <string.h>
+
+int guac_tn5250_user_join_handler(guac_user* user, int argc, char** argv) {
+
+    guac_client* client = user->client;
+    guac_tn5250_client* tn5250_client = (guac_tn5250_client*) client->data;
+
+    /* Parse provided arguments */
+    guac_tn5250_settings* settings = guac_tn5250_parse_args(user,
+            argc, (const char**) argv);
+
+    /* Fail if settings cannot be parsed */
+    if (settings == NULL) {
+        guac_user_log(user, GUAC_LOG_INFO,
+                "Badly formatted client arguments.");
+        return 1;
+    }
+
+    /* Store settings at user level */
+    user->data = settings;
+
+    /* Connect via tn5250 if owner */
+    if (user->owner) {
+
+        /* Store owner's settings at client level */
+        tn5250_client->settings = settings;
+
+        /* Start client thread */
+        if (pthread_create(&(tn5250_client->client_thread), NULL,
+                    guac_tn5250_client_thread, (void*) client)) {
+            guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
+                    "Unable to start tn5250 client thread");
+            return 1;
+        }
+
+    }
+
+    /* If not owner, synchronize with current display */
+    else {
+        guac_terminal_dup(tn5250_client->term, user, user->socket);
+        guac_socket_flush(user->socket);
+    }
+
+    /* Only handle events if not read-only */
+    if (!settings->read_only) {
+
+        /* General mouse/keyboard events */
+        user->key_handler = guac_tn5250_user_key_handler;
+        user->mouse_handler = guac_tn5250_user_mouse_handler;
+
+        /* Inbound (client to server) clipboard transfer */
+        if (!settings->disable_paste)
+            user->clipboard_handler = guac_tn5250_clipboard_handler;
+
+        /* STDIN redirection */
+        user->pipe_handler = guac_tn5250_pipe_handler;
+
+        /* Updates to connection parameters */
+        user->argv_handler = guac_tn5250_argv_handler;
+
+        /* Display size change events */
+        user->size_handler = guac_tn5250_user_size_handler;
+
+    }
+
+    return 0;
+
+}
+
+int guac_tn5250_user_leave_handler(guac_user* user) {
+
+    guac_tn5250_client* tn5250_client =
+        (guac_tn5250_client*) user->client->data;
+
+    /* Update shared cursor state */
+    guac_common_cursor_remove_user(tn5250_client->term->cursor, user);
+
+    /* Free settings if not owner (owner settings will be freed with client) */
+    if (!user->owner) {
+        guac_tn5250_settings* settings = (guac_tn5250_settings*) user->data;
+        guac_tn5250_settings_free(settings);
+    }
+
+    return 0;
+}
+

src/protocols/tn5250/user.h

@@ -0,0 +1,38 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#ifndef GUAC_TN5250_USER_H
+#define GUAC_TN5250_USER_H
+
+#include "config.h"
+
+#include <guacamole/user.h>
+
+/**
+ * Handler for joining users.
+ */
+guac_user_join_handler guac_tn5250_user_join_handler;
+
+/**
+ * Handler for leaving users.
+ */
+guac_user_leave_handler guac_tn5250_user_leave_handler;
+
+#endif
+

src/terminal/terminal/terminal.h

@@ -824,6 +824,18 @@ int guac_terminal_write(guac_terminal* term, const char* c, int size);
 
 /**
  * Sets the character at the given row and column to the specified value.
+ * 
+ * @param term
+ *     The guac_terminal to manipulate.
+ * 
+ * @param row
+ *     The row on which the character is located.
+ * 
+ * @param col
+ *     THe column in which the character is located.
+ * 
+ * @param codepoint
+ *     The value to set.
  */
 int guac_terminal_set(guac_terminal* term, int row, int col, int codepoint);