GUACAMOLE-221: Merge server-side support for parameter prompting.

src/guacd/proc.c

@@ -341,6 +341,9 @@ static void guacd_exec_proc(guacd_proc* proc, const char* protocol) {
 
     }
     
+    /* Enable keep alive on the broadcast socket */
+    guac_socket_require_keep_alive(client->socket);
+
 cleanup_client:
 
     /* Request client to stop/disconnect */

src/libguac/client.c

@@ -478,6 +478,44 @@ int guac_client_load_plugin(guac_client* client, const char* protocol) {
 
 }
 
+/**
+ * A callback function which is invoked by guac_client_owner_send_required() to
+ * send the required parameters to the specified user, who is the owner of the
+ * client session.
+ * 
+ * @param user
+ *     The guac_user that will receive the required parameters, who is the owner
+ *     of the client.
+ * 
+ * @param data
+ *     A pointer to a NULL-terminated array of required parameters that will be
+ *     passed on to the owner to continue the connection.
+ * 
+ * @return
+ *     Zero if the operation succeeds or non-zero on failure, cast as a void*.
+ */
+static void* guac_client_owner_send_required_callback(guac_user* user, void* data) {
+    
+    const char** required = (const char **) data;
+    
+    /* Send required parameters to owner. */
+    if (user != NULL)
+        return (void*) ((intptr_t) guac_protocol_send_required(user->socket, required));
+    
+    return (void*) ((intptr_t) -1);
+    
+}
+
+int guac_client_owner_send_required(guac_client* client, const char** required) {
+
+    /* Don't send required instruction if client does not support it. */
+    if (!guac_client_owner_supports_required(client))
+        return -1;
+    
+    return (int) ((intptr_t) guac_client_for_owner(client, guac_client_owner_send_required_callback, required));
+
+}
+
 /**
  * Updates the provided approximate processing lag, taking into account the
  * processing lag of the given user.
@@ -633,6 +671,36 @@ static void* __webp_support_callback(guac_user* user, void* data) {
 }
 #endif
 
+/**
+ * A callback function which is invoked by guac_client_owner_supports_required()
+ * to determine if the owner of a client supports the "required" instruction,
+ * returning zero if the user does not support the instruction or non-zero if
+ * the user supports it.
+ * 
+ * @param user
+ *     The guac_user that will be checked for "required" instruction support.
+ * 
+ * @param data
+ *     Data provided to the callback. This value is never used within this
+ *     callback.
+ * 
+ * @return
+ *     A non-zero integer if the provided user who owns the connection supports
+ *     the "required" instruction, or zero if the user does not. The integer
+ *     is cast as a void*.
+ */
+static void* guac_owner_supports_required_callback(guac_user* user, void* data) {
+    
+    return (void*) ((intptr_t) guac_user_supports_required(user));
+    
+}
+
+int guac_client_owner_supports_required(guac_client* client) {
+    
+    return (int) ((intptr_t) guac_client_for_owner(client, guac_owner_supports_required_callback, NULL));
+    
+}
+
 int guac_client_supports_webp(guac_client* client) {
 
 #ifdef ENABLE_WEBP

src/libguac/guacamole/client.h

@@ -549,6 +549,22 @@ int guac_client_load_plugin(guac_client* client, const char* protocol);
  */
 int guac_client_get_processing_lag(guac_client* client);
 
+/**
+ * Sends a request to the owner of the given guac_client for parameters required
+ * to continue the connection started by the client. The function returns zero
+ * on success or non-zero on failure.
+ * 
+ * @param client
+ *     The client where additional connection parameters are required.
+ * 
+ * @param required
+ *     The NULL-terminated array of required parameters.
+ * 
+ * @return
+ *     Zero on success, non-zero on failure.
+ */
+int guac_client_owner_send_required(guac_client* client, const char** required);
+
 /**
  * Streams the given connection parameter value over an argument value stream
  * ("argv" instruction), exposing the current value of the named connection
@@ -692,6 +708,21 @@ void guac_client_stream_webp(guac_client* client, guac_socket* socket,
         guac_composite_mode mode, const guac_layer* layer, int x, int y,
         cairo_surface_t* surface, int quality, int lossless);
 
+/**
+ * Returns whether the owner of the given client supports the "required"
+ * instruction, returning non-zero if the client owner does support the
+ * instruction, or zero if the owner does not.
+ * 
+ * @param client
+ *     The Guacamole client whose owner should be checked for supporting
+ *     the "required" instruction.
+ * 
+ * @return 
+ *     Non-zero if the owner of the given client supports the "required"
+ *     instruction, zero otherwise.
+ */
+int guac_client_owner_supports_required(guac_client* client);
+
 /**
  * Returns whether all users of the given client support WebP. If any user does
  * not support WebP, or the server cannot encode WebP images, zero is returned.

src/libguac/guacamole/protocol-constants.h

@@ -38,7 +38,7 @@
  * This version is passed by the __guac_protocol_send_args() function from the
  * server to the client during the client/server handshake.
  */
-#define GUACAMOLE_PROTOCOL_VERSION "VERSION_1_1_0"
+#define GUACAMOLE_PROTOCOL_VERSION "VERSION_1_3_0"
 
 /**
  * The maximum number of bytes that should be sent in any one blob instruction

src/libguac/guacamole/protocol-types.h

@@ -276,5 +276,39 @@ typedef enum guac_line_join_style {
     GUAC_LINE_JOIN_ROUND = 0x2
 } guac_line_join_style;
 
+/**
+ * The set of protocol versions known to guacd to handle negotiation or feature
+ * support between differing versions of Guacamole clients and guacd.
+ */
+typedef enum guac_protocol_version {
+    
+    /**
+     * An unknown version of the Guacamole protocol.
+     */
+    GUAC_PROTOCOL_VERSION_UNKNOWN = 0x000000,
+    
+    /**
+     * Original protocol version 1.0.0, which lacks support for negotiating
+     * parameters and protocol version, and requires that parameters in the
+     * client/server handshake be delivered in order.
+     */
+    GUAC_PROTOCOL_VERSION_1_0_0 = 0x010000,
+            
+    /**
+     * Protocol version 1.1.0, which includes support for parameter and version
+     * negotiation and for sending timezone information from the client
+     * to the server.
+     */
+    GUAC_PROTOCOL_VERSION_1_1_0 = 0x010100,
+            
+    /**
+     * Protocol version 1.3.0, which supports the "required" instruction,
+     * allowing connections in guacd to request information from the client and
+     * await a response.
+     */
+    GUAC_PROTOCOL_VERSION_1_3_0 = 0x010300
+
+} guac_protocol_version;
+
 #endif
 

src/libguac/guacamole/protocol.h

@@ -794,6 +794,22 @@ int guac_protocol_send_push(guac_socket* socket, const guac_layer* layer);
 int guac_protocol_send_rect(guac_socket* socket, const guac_layer* layer,
         int x, int y, int width, int height);
 
+/**
+ * Sends a "required" instruction over the given guac_socket connection.  This
+ * instruction indicates to the client that one or more additional parameters
+ * are needed to continue the connection.
+ * 
+ * @param socket
+ *     The guac_socket connection to which to send the instruction.
+ * 
+ * @param required
+ *     A NULL-terminated array of required parameters.
+ * 
+ * @return
+ *     Zero on success, non-zero on error.
+ */
+int guac_protocol_send_required(guac_socket* socket, const char** required);
+
 /**
  * Sends a reset instruction over the given guac_socket connection.
  *
@@ -1007,5 +1023,32 @@ int guac_protocol_send_name(guac_socket* socket, const char* name);
  */
 int guac_protocol_decode_base64(char* base64);
 
+/**
+ * Given a string representation of a protocol version, return the enum value of
+ * that protocol version, or GUAC_PROTOCOL_VERSION_UNKNOWN if the value is not a
+ * known version.
+ * 
+ * @param version_string
+ *     The string representation of the protocol version.
+ * 
+ * @return 
+ *     The enum value of the protocol version, or GUAC_PROTOCOL_VERSION_UNKNOWN
+ *     if the provided version is not known.
+ */
+guac_protocol_version guac_protocol_string_to_version(const char* version_string);
+
+/**
+ * Given the enum value of the protocol version, return a pointer to the string
+ * representation of the version, or NULL if the version is unknown.
+ * 
+ * @param version
+ *     The enum value of the protocol version.
+ * 
+ * @return 
+ *     A pointer to the string representation of the protocol version, or NULL
+ *     if the version is unknown.
+ */
+const char* guac_protocol_version_to_string(guac_protocol_version version);
+
 #endif
 

src/libguac/guacamole/string.h

@@ -109,6 +109,19 @@ size_t guac_strlcpy(char* restrict dest, const char* restrict src, size_t n);
  */
 size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n);
 
+/**
+ * Simple wrapper for strdup() which behaves identically to standard strdup(),
+ * except that NULL will be returned if the provided string is NULL.
+ *
+ * @param str
+ *     The string to duplicate as a newly-allocated string.
+ *
+ * @return
+ *     A newly-allocated string containing identically the same content as the
+ *     given string, or NULL if the given string was NULL.
+ */
+char* guac_strdup(const char* str);
+
 /**
  * Concatenates each of the given strings, separated by the given delimiter,
  * storing the result within a destination buffer. The number of bytes written

src/libguac/guacamole/user.h

@@ -96,6 +96,12 @@ struct guac_user_info {
      */
     const char* timezone;
     
+    /**
+     * The Guacamole protocol version that the remote system supports, allowing
+     * for feature support to be negotiated between client and server.
+     */
+    guac_protocol_version protocol_version;
+
 };
 
 struct guac_user {
@@ -823,6 +829,17 @@ void guac_user_stream_webp(guac_user* user, guac_socket* socket,
         guac_composite_mode mode, const guac_layer* layer, int x, int y,
         cairo_surface_t* surface, int quality, int lossless);
 
+/**
+ * Returns whether the given user supports the "required" instruction.
+ * 
+ * @param user
+ *     The Guacamole user to check for support of the "required" instruction.
+ * 
+ * @return 
+ *     Non-zero if the user supports the "required" instruction, otherwise zero.
+ */
+int guac_user_supports_required(guac_user* user);
+
 /**
  * Returns whether the given user supports WebP. If the user does not
  * support WebP, or the server cannot encode WebP images, zero is returned.

src/libguac/protocol.c

@@ -23,6 +23,7 @@
 #include "guacamole/layer.h"
 #include "guacamole/object.h"
 #include "guacamole/protocol.h"
+#include "guacamole/protocol-types.h"
 #include "guacamole/socket.h"
 #include "guacamole/stream.h"
 #include "guacamole/unicode.h"
@@ -39,6 +40,34 @@
 #include <string.h>
 #include <sys/types.h>
 
+/**
+ * A structure mapping the enum value of a Guacamole protocol version to the
+ * string representation of the version.
+ */
+typedef struct guac_protocol_version_mapping {
+    
+    /**
+     * The enum value of the protocol version.
+     */
+    guac_protocol_version version;
+    
+    /**
+     * The string value representing the protocol version.
+     */
+    char* version_string;
+    
+} guac_protocol_version_mapping;
+
+/**
+ * The map of known protocol versions to the corresponding string value.
+ */
+guac_protocol_version_mapping guac_protocol_version_table[] = {
+    { GUAC_PROTOCOL_VERSION_1_0_0,   "VERSION_1_0_0" },
+    { GUAC_PROTOCOL_VERSION_1_1_0,   "VERSION_1_1_0" },
+    { GUAC_PROTOCOL_VERSION_1_3_0,   "VERSION_1_3_0" },
+    { GUAC_PROTOCOL_VERSION_UNKNOWN, NULL }
+};
+
 /* Output formatting functions */
 
 ssize_t __guac_socket_write_length_string(guac_socket* socket, const char* str) {
@@ -66,6 +95,38 @@ ssize_t __guac_socket_write_length_double(guac_socket* socket, double d) {
 
 }
 
+/**
+ * Loop through the provided NULL-terminated array, writing the values in the
+ * array to the given socket. Values are written as a series of Guacamole
+ * protocol elements, including the leading comma and the value length in
+ * addition to the value itself. Returns zero on success, non-zero on error.
+ *
+ * @param socket
+ *     The socket to which the data should be written.
+ *
+ * @param array
+ *     The NULL-terminated array of values to write.
+ *
+ * @return
+ *     Zero on success, non-zero on error.
+ */
+static int guac_socket_write_array(guac_socket* socket, const char** array) {
+
+    /* Loop through array, writing provided values to the socket. */
+    for (int i=0; array[i] != NULL; i++) {
+
+        if (guac_socket_write_string(socket, ","))
+            return -1;
+
+        if (__guac_socket_write_length_string(socket, array[i]))
+            return -1;
+
+    }
+
+    return 0;
+
+}
+
 /* Protocol functions */
 
 int guac_protocol_send_ack(guac_socket* socket, guac_stream* stream,
@@ -90,8 +151,6 @@ int guac_protocol_send_ack(guac_socket* socket, guac_stream* stream,
 
 static int __guac_protocol_send_args(guac_socket* socket, const char** args) {
 
-    int i;
-
     if (guac_socket_write_string(socket, "4.args")) return -1;
     
     /* Send protocol version ahead of other args. */
@@ -99,15 +158,8 @@ static int __guac_protocol_send_args(guac_socket* socket, const char** args) {
             || __guac_socket_write_length_string(socket, GUACAMOLE_PROTOCOL_VERSION))
         return -1;
 
-    for (i=0; args[i] != NULL; i++) {
+    if (guac_socket_write_array(socket, args))
-
+        return -1;
-        if (guac_socket_write_string(socket, ","))
-            return -1;
-
-        if (__guac_socket_write_length_string(socket, args[i]))
-            return -1;
-
-    }
 
     return guac_socket_write_string(socket, ";");
 
@@ -308,19 +360,11 @@ int guac_protocol_send_close(guac_socket* socket, const guac_layer* layer) {
 
 static int __guac_protocol_send_connect(guac_socket* socket, const char** args) {
 
-    int i;
+    if (guac_socket_write_string(socket, "7.connect"))
+        return -1;
 
-    if (guac_socket_write_string(socket, "7.connect")) return -1;
+    if (guac_socket_write_array(socket, args))
-
+        return -1;
-    for (i=0; args[i] != NULL; i++) {
-
-        if (guac_socket_write_string(socket, ","))
-            return -1;
-
-        if (__guac_socket_write_length_string(socket, args[i]))
-            return -1;
-
-    }
 
     return guac_socket_write_string(socket, ";");
 
@@ -961,6 +1005,23 @@ int guac_protocol_send_rect(guac_socket* socket,
 
 }
 
+int guac_protocol_send_required(guac_socket* socket, const char** required) {
+    
+    int ret_val;
+    
+    guac_socket_instruction_begin(socket);
+
+    ret_val = guac_socket_write_string(socket, "8.required")
+        || guac_socket_write_array(socket, required)
+        || guac_socket_write_string(socket, ";")
+        || guac_socket_flush(socket);
+    
+    guac_socket_instruction_end(socket);
+
+    return ret_val;
+    
+}
+
 int guac_protocol_send_reset(guac_socket* socket, const guac_layer* layer) {
 
     int ret_val;
@@ -1241,3 +1302,35 @@ int guac_protocol_decode_base64(char* base64) {
 
 }
 
+guac_protocol_version guac_protocol_string_to_version(const char* version_string) {
+    
+    guac_protocol_version_mapping* current = guac_protocol_version_table;
+    while (current->version != GUAC_PROTOCOL_VERSION_UNKNOWN) {
+        
+        if (strcmp(current->version_string, version_string) == 0)
+            return current->version;
+        
+        current++;
+        
+    }
+    
+    return GUAC_PROTOCOL_VERSION_UNKNOWN;
+    
+}
+
+const char* guac_protocol_version_to_string(guac_protocol_version version) {
+    
+    guac_protocol_version_mapping* current = guac_protocol_version_table;
+    while (current->version != GUAC_PROTOCOL_VERSION_UNKNOWN) {
+        
+        if (current->version == version)
+            return (const char*) current->version_string;
+        
+        current++;
+        
+    }
+    
+    return NULL;
+    
+}
+

src/libguac/string.c

@@ -81,6 +81,17 @@ size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n) {
 
 }
 
+char* guac_strdup(const char* str) {
+
+    /* Return NULL if no string provided */
+    if (str == NULL)
+        return NULL;
+
+    /* Otherwise just invoke strdup() */
+    return strdup(str);
+
+}
+
 size_t guac_strljoin(char* restrict dest, const char* restrict const* elements,
         int nmemb, const char* restrict delim, size_t n) {
 

src/libguac/tests/Makefile.am

@@ -40,8 +40,10 @@ test_libguac_SOURCES =               \
     parser/read.c                    \
     pool/next_free.c                 \
     protocol/base64_decode.c         \
+    protocol/guac_protocol_version.c \
     socket/fd_send_instruction.c     \
     socket/nested_send_instruction.c \
+    string/strdup.c                  \
     string/strlcat.c                 \
     string/strlcpy.c                 \
     string/strljoin.c                \

src/libguac/tests/protocol/guac_protocol_version.c

@@ -0,0 +1,69 @@
+/*
+ * 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 <CUnit/CUnit.h>
+#include <guacamole/protocol.h>
+#include <guacamole/protocol-types.h>
+
+/**
+ * Test which verifies that conversion of the guac_protocol_version enum to
+ * string values succeeds and produces the expected results.
+ */
+void test_guac_protocol__version_to_string() {
+    
+    guac_protocol_version version_a = GUAC_PROTOCOL_VERSION_1_3_0;
+    guac_protocol_version version_b = GUAC_PROTOCOL_VERSION_1_0_0;
+    guac_protocol_version version_c = GUAC_PROTOCOL_VERSION_UNKNOWN;
+    
+    CU_ASSERT_STRING_EQUAL(guac_protocol_version_to_string(version_a), "VERSION_1_3_0");
+    CU_ASSERT_STRING_EQUAL(guac_protocol_version_to_string(version_b), "VERSION_1_0_0");
+    CU_ASSERT_PTR_NULL(guac_protocol_version_to_string(version_c));
+    
+}
+
+/**
+ * Test which verifies that the version of String representations of Guacamole
+ * protocol versions are successfully converted into their matching
+ * guac_protocol_version enum values, and that versions that do not match
+ * any version get the correct unknown value.
+ */
+void test_guac_protocol__string_to_version() {
+    
+    char* str_version_a = "VERSION_1_3_0";
+    char* str_version_b = "VERSION_1_1_0";
+    char* str_version_c = "AVACADO";
+    char* str_version_d = "VERSION_31_4_1";
+    
+    CU_ASSERT_EQUAL(guac_protocol_string_to_version(str_version_a), GUAC_PROTOCOL_VERSION_1_3_0);
+    CU_ASSERT_EQUAL(guac_protocol_string_to_version(str_version_b), GUAC_PROTOCOL_VERSION_1_1_0);
+    CU_ASSERT_EQUAL(guac_protocol_string_to_version(str_version_c), GUAC_PROTOCOL_VERSION_UNKNOWN);
+    CU_ASSERT_EQUAL(guac_protocol_string_to_version(str_version_d), GUAC_PROTOCOL_VERSION_UNKNOWN);
+    
+}
+
+/**
+ * Test which verifies that the comparisons between guac_protocol_version enum
+ * values produces the expected results.
+ */
+void test_gauc_protocol__version_comparison() {
+    
+    CU_ASSERT_TRUE(GUAC_PROTOCOL_VERSION_1_3_0 > GUAC_PROTOCOL_VERSION_1_0_0);
+    CU_ASSERT_TRUE(GUAC_PROTOCOL_VERSION_UNKNOWN < GUAC_PROTOCOL_VERSION_1_1_0);
+    
+}

src/libguac/tests/string/strdup.c

@@ -0,0 +1,49 @@
+/*
+ * 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 <CUnit/CUnit.h>
+#include <guacamole/string.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ * Source test string for copying.
+ */
+const char* source_string = "Mashing avocados.";
+
+/**
+ * A NULL string variable for copying to insure that NULL is copied properly.
+ */
+const char* null_string = NULL;
+
+/**
+ * Verify guac_strdup() behavior when the string is both NULL and not NULL.
+ */
+void test_string__strdup() {
+
+    /* Copy the strings. */
+    char* dest_string = guac_strdup(source_string);
+    char* null_copy = guac_strdup(null_string);
+    
+    /* Run the tests. */
+    CU_ASSERT_STRING_EQUAL(dest_string, "Mashing avocados.");
+    CU_ASSERT_PTR_NULL(null_copy);
+
+}

src/libguac/user-handshake.c

@@ -344,12 +344,16 @@ int guac_user_handle_connection(guac_user* user, int usec_timeout) {
         guac_client_log(client, GUAC_LOG_INFO, "User \"%s\" joined connection "
                 "\"%s\" (%i users now present)", user->user_id,
                 client->connection_id, client->connected_users);
-        if (strcmp(parser->argv[0],"") != 0)
+        if (strcmp(parser->argv[0],"") != 0) {
             guac_client_log(client, GUAC_LOG_DEBUG, "Client is using protocol "
                     "version \"%s\"", parser->argv[0]);
-        else
+            user->info.protocol_version = guac_protocol_string_to_version(parser->argv[0]);
+        }
+        else {
             guac_client_log(client, GUAC_LOG_DEBUG, "Client has not defined "
                     "its protocol version.");
+            user->info.protocol_version = GUAC_PROTOCOL_VERSION_1_0_0;
+        }
 
         /* Handle user I/O, wait for connection to terminate */
         guac_user_start(parser, user, usec_timeout);

src/libguac/user.c

@@ -316,6 +316,15 @@ void guac_user_stream_webp(guac_user* user, guac_socket* socket,
 
 }
 
+int guac_user_supports_required(guac_user* user) {
+    
+    if (user == NULL)
+        return 0;
+    
+    return (user->info.protocol_version >= GUAC_PROTOCOL_VERSION_1_3_0);
+    
+}
+
 int guac_user_supports_webp(guac_user* user) {
 
 #ifdef ENABLE_WEBP

src/protocols/rdp/Makefile.am

@@ -38,6 +38,7 @@ nodist_libguac_client_rdp_la_SOURCES =  \
     _generated_keymaps.c
 
 libguac_client_rdp_la_SOURCES =                  \
+    argv.c                                       \
     beep.c                                       \
     bitmap.c                                     \
     channels/audio-input/audio-buffer.c          \
@@ -82,6 +83,7 @@ libguac_client_rdp_la_SOURCES =                  \
     user.c
 
 noinst_HEADERS =                                 \
+    argv.h                                       \
     beep.h                                       \
     bitmap.h                                     \
     channels/audio-input/audio-buffer.h          \

src/protocols/rdp/argv.c

@@ -0,0 +1,60 @@
+/*
+ * 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 "rdp.h"
+#include "settings.h"
+
+#include <guacamole/protocol.h>
+#include <guacamole/socket.h>
+#include <guacamole/user.h>
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+
+int guac_rdp_argv_callback(guac_user* user, const char* mimetype,
+        const char* name, const char* value, void* data) {
+
+    guac_client* client = user->client;
+    guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
+    guac_rdp_settings* settings = rdp_client->settings;
+
+    /* Update username */
+    if (strcmp(name, GUAC_RDP_ARGV_USERNAME) == 0) {
+        free(settings->username);
+        settings->username = strdup(value);
+    }
+    
+    /* Update password */
+    else if (strcmp(name, GUAC_RDP_ARGV_PASSWORD) == 0) {
+        free(settings->password);
+        settings->password = strdup(value);
+    }
+    
+    /* Update domain */
+    else if (strcmp(name, GUAC_RDP_ARGV_DOMAIN) == 0) {
+        free(settings->domain);
+        settings->domain = strdup(value);
+    }
+
+    return 0;
+
+}

src/protocols/rdp/argv.h

@@ -0,0 +1,54 @@
+/*
+ * 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_RDP_ARGV_H
+#define GUAC_RDP_ARGV_H
+
+#include "config.h"
+
+#include <guacamole/argv.h>
+#include <guacamole/user.h>
+
+/**
+ * Handles a received argument value from a Guacamole "argv" instruction,
+ * updating the given connection parameter.
+ */
+guac_argv_callback guac_rdp_argv_callback;
+
+/**
+ * The name of the parameter that specifies/updates the username that will be
+ * sent to the RDP server during authentication.
+ */
+#define GUAC_RDP_ARGV_USERNAME "username"
+
+/**
+ * The name of the parameter that specifies/updates the password that will be
+ * sent to the RDP server during authentication.
+ */
+#define GUAC_RDP_ARGV_PASSWORD "password"
+
+/**
+ * The name of the parameter that specifies/updates the domain name that will be
+ * sent to the RDP server during authentication.
+ */
+#define GUAC_RDP_ARGV_DOMAIN "domain"
+
+#endif
+

src/protocols/rdp/rdp.c

@@ -17,6 +17,7 @@
  * under the License.
  */
 
+#include "argv.h"
 #include "beep.h"
 #include "bitmap.h"
 #include "channels/audio-input/audio-buffer.h"
@@ -42,6 +43,7 @@
 #include "pointer.h"
 #include "print-job.h"
 #include "rdp.h"
+#include "settings.h"
 
 #ifdef ENABLE_COMMON_SSH
 #include "common-ssh/sftp.h"
@@ -64,10 +66,12 @@
 #include <freerdp/primary.h>
 #include <freerdp/settings.h>
 #include <freerdp/update.h>
+#include <guacamole/argv.h>
 #include <guacamole/audio.h>
 #include <guacamole/client.h>
 #include <guacamole/protocol.h>
 #include <guacamole/socket.h>
+#include <guacamole/string.h>
 #include <guacamole/timestamp.h>
 #include <guacamole/wol.h>
 #include <winpr/error.h>
@@ -200,10 +204,15 @@ BOOL rdp_freerdp_pre_connect(freerdp* instance) {
 }
 
 /**
- * Callback invoked by FreeRDP when authentication is required but a username
+ * Callback invoked by FreeRDP when authentication is required but the required
- * and password has not already been given. In the case of Guacamole, this
+ * parameters have not been provided. In the case of Guacamole clients that
- * function always succeeds but does not populate the usename or password. The
+ * support the "required" instruction, this function will send any of the three
- * username/password must be given within the connection parameters.
+ * unpopulated RDP authentication parameters back to the client so that the
+ * connection owner can provide the required information.  If the values have
+ * been provided in the original connection parameters the user will not be
+ * prompted for updated parameters. If the version of Guacamole Client in use
+ * by the connection owner does not support the "required" instruction then the
+ * connection will fail. This function always returns true.
  *
  * @param instance
  *     The FreeRDP instance associated with the RDP session requesting
@@ -227,10 +236,63 @@ static BOOL rdp_freerdp_authenticate(freerdp* instance, char** username,
 
     rdpContext* context = instance->context;
     guac_client* client = ((rdp_freerdp_context*) context)->client;
+    guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
+    guac_rdp_settings* settings = rdp_client->settings;
+    char* params[4] = {NULL};
+    int i = 0;
     
-    /* Warn if connection is likely to fail due to lack of credentials */
+    /* If the client does not support the "required" instruction, warn and
-    guac_client_log(client, GUAC_LOG_INFO,
+     * quit.
-            "Authentication requested but username or password not given");
+     */
+    if (!guac_client_owner_supports_required(client)) {
+        guac_client_log(client, GUAC_LOG_WARNING, "Client does not support the "
+                "\"required\" instruction. No authentication parameters will "
+                "be requested.");
+        return TRUE;
+    }
+
+    /* If the username is undefined, add it to the requested parameters. */
+    if (settings->username == NULL) {
+        guac_argv_register(GUAC_RDP_ARGV_USERNAME, guac_rdp_argv_callback, NULL, 0);
+        params[i] = GUAC_RDP_ARGV_USERNAME;
+        i++;
+        
+        /* If username is undefined and domain is also undefined, request domain. */
+        if (settings->domain == NULL) {
+            guac_argv_register(GUAC_RDP_ARGV_DOMAIN, guac_rdp_argv_callback, NULL, 0);
+            params[i] = GUAC_RDP_ARGV_DOMAIN;
+            i++;
+        }
+        
+    }
+    
+    /* If the password is undefined, add it to the requested parameters. */
+    if (settings->password == NULL) {
+        guac_argv_register(GUAC_RDP_ARGV_PASSWORD, guac_rdp_argv_callback, NULL, 0);
+        params[i] = GUAC_RDP_ARGV_PASSWORD;
+        i++;
+    }
+    
+    /* NULL-terminate the array. */
+    params[i] = NULL;
+    
+    if (i > 0) {
+        
+        /* Send required parameters to the owner and wait for the response. */
+        guac_client_owner_send_required(client, (const char**) params);
+        guac_argv_await((const char**) params);
+        
+        /* Free old values and get new values from settings. */
+        free(*username);
+        free(*password);
+        free(*domain);
+        *username = guac_strdup(settings->username);
+        *password = guac_strdup(settings->password);
+        *domain = guac_strdup(settings->domain);
+        
+    }
+    
+    /* Always return TRUE allowing connection to retry. */
     return TRUE;
 
 }

src/protocols/rdp/settings.c

@@ -17,6 +17,7 @@
  * under the License.
  */
 
+#include "argv.h"
 #include "common/defaults.h"
 #include "common/string.h"
 #include "config.h"
@@ -42,9 +43,9 @@
 const char* GUAC_RDP_CLIENT_ARGS[] = {
     "hostname",
     "port",
-    "domain",
+    GUAC_RDP_ARGV_DOMAIN,
-    "username",
+    GUAC_RDP_ARGV_USERNAME,
-    "password",
+    GUAC_RDP_ARGV_PASSWORD,
     "width",
     "height",
     "dpi",
@@ -1266,47 +1267,25 @@ static int guac_rdp_get_performance_flags(guac_rdp_settings* guac_settings) {
 
 }
 
-/**
- * Simple wrapper for strdup() which behaves identically to standard strdup(),
- * execpt that NULL will be returned if the provided string is NULL.
- *
- * @param str
- *     The string to duplicate as a newly-allocated string.
- *
- * @return
- *     A newly-allocated string containing identically the same content as the
- *     given string, or NULL if the given string was NULL.
- */
-static char* guac_rdp_strdup(const char* str) {
-
-    /* Return NULL if no string provided */
-    if (str == NULL)
-        return NULL;
-
-    /* Otherwise just invoke strdup() */
-    return strdup(str);
-
-}
-
 void guac_rdp_push_settings(guac_client* client,
         guac_rdp_settings* guac_settings, freerdp* rdp) {
 
     rdpSettings* rdp_settings = rdp->settings;
 
     /* Authentication */
-    rdp_settings->Domain = guac_rdp_strdup(guac_settings->domain);
+    rdp_settings->Domain = guac_strdup(guac_settings->domain);
-    rdp_settings->Username = guac_rdp_strdup(guac_settings->username);
+    rdp_settings->Username = guac_strdup(guac_settings->username);
-    rdp_settings->Password = guac_rdp_strdup(guac_settings->password);
+    rdp_settings->Password = guac_strdup(guac_settings->password);
 
     /* Connection */
-    rdp_settings->ServerHostname = guac_rdp_strdup(guac_settings->hostname);
+    rdp_settings->ServerHostname = guac_strdup(guac_settings->hostname);
     rdp_settings->ServerPort = guac_settings->port;
 
     /* Session */
     rdp_settings->ColorDepth = guac_settings->color_depth;
     rdp_settings->DesktopWidth = guac_settings->width;
     rdp_settings->DesktopHeight = guac_settings->height;
-    rdp_settings->AlternateShell = guac_rdp_strdup(guac_settings->initial_program);
+    rdp_settings->AlternateShell = guac_strdup(guac_settings->initial_program);
     rdp_settings->KeyboardLayout = guac_settings->server_layout->freerdp_keyboard_layout;
 
     /* Performance flags */
@@ -1424,9 +1403,9 @@ void guac_rdp_push_settings(guac_client* client,
         rdp_settings->Workarea = TRUE;
         rdp_settings->RemoteApplicationMode = TRUE;
         rdp_settings->RemoteAppLanguageBarSupported = TRUE;
-        rdp_settings->RemoteApplicationProgram = guac_rdp_strdup(guac_settings->remote_app);
+        rdp_settings->RemoteApplicationProgram = guac_strdup(guac_settings->remote_app);
-        rdp_settings->ShellWorkingDirectory = guac_rdp_strdup(guac_settings->remote_app_dir);
+        rdp_settings->ShellWorkingDirectory = guac_strdup(guac_settings->remote_app_dir);
-        rdp_settings->RemoteApplicationCmdLine = guac_rdp_strdup(guac_settings->remote_app_args);
+        rdp_settings->RemoteApplicationCmdLine = guac_strdup(guac_settings->remote_app_args);
     }
 
     /* Preconnection ID */
@@ -1440,7 +1419,7 @@ void guac_rdp_push_settings(guac_client* client,
     if (guac_settings->preconnection_blob != NULL) {
         rdp_settings->NegotiateSecurityLayer = FALSE;
         rdp_settings->SendPreconnectionPdu = TRUE;
-        rdp_settings->PreconnectionBlob = guac_rdp_strdup(guac_settings->preconnection_blob);
+        rdp_settings->PreconnectionBlob = guac_strdup(guac_settings->preconnection_blob);
     }
 
     /* Enable use of RD gateway if a gateway hostname is provided */
@@ -1450,20 +1429,20 @@ void guac_rdp_push_settings(guac_client* client,
         rdp_settings->GatewayEnabled = TRUE;
 
         /* RD gateway connection details */
-        rdp_settings->GatewayHostname = guac_rdp_strdup(guac_settings->gateway_hostname);
+        rdp_settings->GatewayHostname = guac_strdup(guac_settings->gateway_hostname);
         rdp_settings->GatewayPort = guac_settings->gateway_port;
 
         /* RD gateway credentials */
         rdp_settings->GatewayUseSameCredentials = FALSE;
-        rdp_settings->GatewayDomain = guac_rdp_strdup(guac_settings->gateway_domain);
+        rdp_settings->GatewayDomain = guac_strdup(guac_settings->gateway_domain);
-        rdp_settings->GatewayUsername = guac_rdp_strdup(guac_settings->gateway_username);
+        rdp_settings->GatewayUsername = guac_strdup(guac_settings->gateway_username);
-        rdp_settings->GatewayPassword = guac_rdp_strdup(guac_settings->gateway_password);
+        rdp_settings->GatewayPassword = guac_strdup(guac_settings->gateway_password);
 
     }
 
     /* Store load balance info (and calculate length) if provided */
     if (guac_settings->load_balance_info != NULL) {
-        rdp_settings->LoadBalanceInfo = (BYTE*) guac_rdp_strdup(guac_settings->load_balance_info);
+        rdp_settings->LoadBalanceInfo = (BYTE*) guac_strdup(guac_settings->load_balance_info);
         rdp_settings->LoadBalanceInfoLength = strlen(guac_settings->load_balance_info);
     }
 

src/protocols/rdp/user.c

@@ -33,6 +33,7 @@
 #include "sftp.h"
 #endif
 
+#include <guacamole/argv.h>
 #include <guacamole/audio.h>
 #include <guacamole/client.h>
 #include <guacamole/protocol.h>
@@ -117,6 +118,10 @@ int guac_rdp_user_join_handler(guac_user* user, int argc, char** argv) {
         /* Inbound arbitrary named pipes */
         user->pipe_handler = guac_rdp_pipe_svc_pipe_handler;
         
+        /* If we own it, register handler for updating parameters during connection. */
+        if (user->owner)
+            user->argv_handler = guac_argv_handler;
+
     }
 
     return 0;

src/protocols/vnc/Makefile.am

@@ -29,6 +29,7 @@ ACLOCAL_AMFLAGS = -I m4
 lib_LTLIBRARIES = libguac-client-vnc.la
 
 libguac_client_vnc_la_SOURCES = \
+    argv.c                      \
     auth.c                      \
     client.c                    \
     clipboard.c                 \
@@ -41,6 +42,7 @@ libguac_client_vnc_la_SOURCES = \
     vnc.c
     
 noinst_HEADERS =      \
+    argv.h            \
     auth.h            \
     client.h          \
     clipboard.h       \

src/protocols/vnc/argv.c

@@ -0,0 +1,53 @@
+/*
+ * 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 "vnc.h"
+
+#include <guacamole/protocol.h>
+#include <guacamole/socket.h>
+#include <guacamole/user.h>
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+
+int guac_vnc_argv_callback(guac_user* user, const char* mimetype,
+        const char* name, const char* value, void* data) {
+
+    guac_client* client = user->client;
+    guac_vnc_client* vnc_client = (guac_vnc_client*) client->data;
+    guac_vnc_settings* settings = vnc_client->settings;
+
+    /* Update username */
+    if (strcmp(name, GUAC_VNC_ARGV_USERNAME) == 0) {
+        free(settings->username);
+        settings->username = strdup(value);
+    }
+    
+    /* Update password */
+    else if (strcmp(name, GUAC_VNC_ARGV_PASSWORD) == 0) {
+        free(settings->password);
+        settings->password = strdup(value);
+    }
+
+    return 0;
+
+}

src/protocols/vnc/argv.h

@@ -0,0 +1,47 @@
+/*
+ * 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 ARGV_H
+#define ARGV_H
+
+#include "config.h"
+
+#include <guacamole/argv.h>
+#include <guacamole/user.h>
+
+/**
+ * Handles a received argument value from a Guacamole "argv" instruction,
+ * updating the given connection parameter.
+ */
+guac_argv_callback guac_vnc_argv_callback;
+
+/**
+ * The name of the parameter Guacamole will use to specify/update the username
+ * for the VNC connection.
+ */
+#define GUAC_VNC_ARGV_USERNAME "username"
+
+/**
+ * The name of the parameter Guacamole will use to specify/update the password
+ * for the VNC connection.
+ */
+#define GUAC_VNC_ARGV_PASSWORD "password"
+
+#endif /* ARGV_H */
+

src/protocols/vnc/auth.c

@@ -19,27 +19,94 @@
 
 #include "config.h"
 
+#include "argv.h"
 #include "auth.h"
 #include "vnc.h"
 
+#include <guacamole/argv.h>
 #include <guacamole/client.h>
+#include <guacamole/protocol.h>
+#include <guacamole/socket.h>
+#include <guacamole/string.h>
 #include <rfb/rfbclient.h>
 #include <rfb/rfbproto.h>
 
+#include <pthread.h>
+#include <string.h>
+
 char* guac_vnc_get_password(rfbClient* client) {
     guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
-    return ((guac_vnc_client*) gc->data)->settings->password;
+    guac_vnc_client* vnc_client = ((guac_vnc_client*) gc->data);
+    guac_vnc_settings* settings = vnc_client->settings;
+    
+    /* If the client does not support the "required" instruction, just return
+        the configuration data. */
+    if (!guac_client_owner_supports_required(gc))
+        return guac_strdup(settings->password);
+    
+    /* If password isn't around, prompt for it. */
+    if (settings->password == NULL) {
+        
+        guac_argv_register(GUAC_VNC_ARGV_PASSWORD, guac_vnc_argv_callback, NULL, 0);
+        
+        const char* params[] = {GUAC_VNC_ARGV_PASSWORD, NULL};
+        
+        /* Send the request for password to the owner. */
+        guac_client_owner_send_required(gc, params);
+                
+        /* Wait for the arguments to be returned */
+        guac_argv_await(params);
+
+    }
+    
+    return guac_strdup(settings->password);
+    
 }
 
 rfbCredential* guac_vnc_get_credentials(rfbClient* client, int credentialType) {
-    guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
-    guac_vnc_settings* settings = ((guac_vnc_client*) gc->data)->settings;
     
+    guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
+    guac_vnc_client* vnc_client = ((guac_vnc_client*) gc->data);
+    guac_vnc_settings* settings = vnc_client->settings;
+    
+    /* Handle request for Username/Password credentials */
     if (credentialType == rfbCredentialTypeUser) {
         rfbCredential *creds = malloc(sizeof(rfbCredential));
-        creds->userCredential.username = settings->username;
+        
-        creds->userCredential.password = settings->password;
+        /* If the client supports the "required" instruction, prompt for and
+           update those. */
+        if (guac_client_owner_supports_required(gc)) {
+            char* params[3] = {NULL};
+            int i = 0;
+
+            /* Check if username is not provided. */
+            if (settings->username == NULL) {
+                guac_argv_register(GUAC_VNC_ARGV_USERNAME, guac_vnc_argv_callback, NULL, 0);
+                params[i] = GUAC_VNC_ARGV_USERNAME;
+                i++;
+            }
+
+            /* Check if password is not provided. */
+            if (settings->password == NULL) {
+                guac_argv_register(GUAC_VNC_ARGV_PASSWORD, guac_vnc_argv_callback, NULL, 0);
+                params[i] = GUAC_VNC_ARGV_PASSWORD;
+                i++;
+            }
+
+            params[i] = NULL;
+
+            /* If we have empty parameters, request them and await response. */
+            if (i > 0) {
+                guac_client_owner_send_required(gc, (const char**) params);
+                guac_argv_await((const char**) params);
+            }
+        }
+        
+        /* Copy the values and return the credential set. */
+        creds->userCredential.username = guac_strdup(settings->username);
+        creds->userCredential.password = guac_strdup(settings->password);
         return creds;
+        
     }
 
     guac_client_abort(gc, GUAC_PROTOCOL_STATUS_SERVER_ERROR,

src/protocols/vnc/client.c

@@ -50,8 +50,8 @@ int guac_client_init(guac_client* client) {
     client->data = vnc_client;
 
 #ifdef ENABLE_VNC_TLS_LOCKING
-    /* Initialize the write lock */
+    /* Initialize the TLS write lock */
-    pthread_mutex_init(&(vnc_client->tls_lock), NULL);
+    pthread_mutex_init(&vnc_client->tls_lock, NULL);
 #endif
 
     /* Init clipboard */

src/protocols/vnc/settings.c

@@ -19,6 +19,7 @@
 
 #include "config.h"
 
+#include "argv.h"
 #include "client.h"
 #include "common/defaults.h"
 #include "settings.h"
@@ -37,8 +38,8 @@ const char* GUAC_VNC_CLIENT_ARGS[] = {
     "port",
     "read-only",
     "encodings",
-    "username",
+    GUAC_VNC_ARGV_USERNAME,
-    "password",
+    GUAC_VNC_ARGV_PASSWORD,
     "swap-red-blue",
     "color-depth",
     "cursor",
@@ -392,11 +393,11 @@ guac_vnc_settings* guac_vnc_parse_args(guac_user* user,
 
     settings->username =
         guac_user_parse_args_string(user, GUAC_VNC_CLIENT_ARGS, argv,
-                IDX_USERNAME, ""); /* NOTE: freed by libvncclient */
+                IDX_USERNAME, NULL);
     
     settings->password =
         guac_user_parse_args_string(user, GUAC_VNC_CLIENT_ARGS, argv,
-                IDX_PASSWORD, ""); /* NOTE: freed by libvncclient */
+                IDX_PASSWORD, NULL);
     
     /* Remote cursor */
     if (strcmp(argv[IDX_CURSOR], "remote") == 0) {
@@ -624,8 +625,10 @@ void guac_vnc_settings_free(guac_vnc_settings* settings) {
     free(settings->clipboard_encoding);
     free(settings->encodings);
     free(settings->hostname);
+    free(settings->password);
     free(settings->recording_name);
     free(settings->recording_path);
+    free(settings->username);
 
 #ifdef ENABLE_VNC_REPEATER
     /* Free VNC repeater settings */

src/protocols/vnc/user.c

@@ -32,6 +32,7 @@
 #include "pulse/pulse.h"
 #endif
 
+#include <guacamole/argv.h>
 #include <guacamole/audio.h>
 #include <guacamole/client.h>
 #include <guacamole/socket.h>
@@ -99,6 +100,10 @@ int guac_vnc_user_join_handler(guac_user* user, int argc, char** argv) {
         if (!settings->disable_paste)
             user->clipboard_handler = guac_vnc_clipboard_handler;
         
+        /* Updates to connection parameters if we own the connection */
+        if (user->owner)
+            user->argv_handler = guac_argv_handler;
+
 #ifdef ENABLE_COMMON_SSH
         /* Set generic (non-filesystem) file upload handler */
         if (settings->enable_sftp && !settings->sftp_disable_upload)

src/protocols/vnc/vnc.c

@@ -259,9 +259,6 @@ void* guac_vnc_client_thread(void* data) {
                 "clipboard encoding: '%s'.", settings->clipboard_encoding);
     }
 
-    /* Ensure connection is kept alive during lengthy connects */
-    guac_socket_require_keep_alive(client->socket);
-
     /* Set up libvncclient logging */
     rfbClientLog = guac_vnc_client_log_info;
     rfbClientErr = guac_vnc_client_log_error;