GUACAMOLE-221: Fix up lots of comments, streamline code, and fix SSH mutex lock.

src/libguac/guacamole/protocol-types.h

@@ -20,8 +20,6 @@
 #ifndef _GUAC_PROTOCOL_TYPES_H
 #define _GUAC_PROTOCOL_TYPES_H
 
-#include <stddef.h>
-
 /**
  * Type definitions related to the Guacamole protocol.
  *

src/libguac/protocol.c

@@ -96,9 +96,10 @@ ssize_t __guac_socket_write_length_double(guac_socket* socket, double d) {
 }
 
 /**
- * Loop through the provided NULL-terminated array, writing the values
- * and lengths of the values in the array to the given socket. Return
- * zero on success, non-zero on error.
+ * 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.
@@ -111,7 +112,7 @@ ssize_t __guac_socket_write_length_double(guac_socket* socket, double d) {
  */
 static int guac_socket_write_array(guac_socket* socket, const char** array) {
 
-	/* Loop through array, writing provided values to the socket. */
+    /* Loop through array, writing provided values to the socket. */
     for (int i=0; array[i] != NULL; i++) {
 
         if (guac_socket_write_string(socket, ","))
@@ -122,7 +123,7 @@ static int guac_socket_write_array(guac_socket* socket, const char** array) {
 
     }
 
-	return 0;
+    return 0;
 
 }
 
@@ -1010,13 +1011,9 @@ int guac_protocol_send_required(guac_socket* socket, const char** required) {
     
     guac_socket_instruction_begin(socket);
 
-    if (guac_socket_write_string(socket, "8.required"))
-        return -1;
-
-    if (guac_socket_write_array(socket, required))
-        return -1;
-
-    ret_val = guac_socket_write_string(socket, ";");
+    ret_val = guac_socket_write_string(socket, "8.required")
+        || guac_socket_write_array(socket, required)
+        || guac_socket_write_string(socket, ";");
     
     guac_socket_instruction_end(socket);
 

src/protocols/rdp/rdp.h

@@ -183,7 +183,12 @@ typedef struct guac_rdp_client {
     
     /**
      * Flags for tracking events related to the rdp_credential_cond
-     * pthread condition.
+     * pthread condition. These flags will be set when credential parameters
+     * are required by the connection, and cleared when those have been
+     * provided by the client.  All flags are cleared at the start of the
+     * connection, and then set as the client determines that further
+     * information is required.
+     * 
      * 
      * @see GUAC_RDP_CRED_FLAG_USERNAME
      * @see GUAC_RDP_CRED_FLAG_PASSWORD

src/protocols/ssh/client.c

@@ -120,6 +120,10 @@ int guac_ssh_client_free_handler(guac_client* client) {
     guac_common_clipboard_free(ssh_client->clipboard);
     free(ssh_client);
 
+    /* Destroy the pthread conditional handler */
+    pthread_cond_destroy(&(ssh_client->ssh_credential_cond));
+    pthread_mutex_destroy(&(ssh_client->ssh_credential_lock));
+    
     guac_common_ssh_uninit();
     return 0;
 }

src/protocols/ssh/ssh.c

@@ -58,6 +58,35 @@
 #include <sys/socket.h>
 #include <sys/time.h>
 
+/**
+ * A data structure that maps parameter names of credentials that will be
+ * prompted to the actual text that will be displayed on the screen.
+ */
+typedef struct guac_ssh_credential_prompt_map {
+    
+    /**
+     * The parameter name of the credential that is being prompted for.
+     */
+    char* name;
+    
+    /**
+     * The text that will display to the user during the prompt.
+     */
+    char* prompt;
+    
+} guac_ssh_credential_prompt_map;
+
+/**
+ * The map of credentials the user can be prompted for to the text displayed
+ * on the screen.
+ */
+guac_ssh_credential_prompt_map ssh_credential_prompt_map[] = {
+    { GUAC_SSH_PARAMETER_NAME_USERNAME,   "Login as: " },
+    { GUAC_SSH_PARAMETER_NAME_PASSWORD,   "Password: " },
+    { GUAC_SSH_PARAMETER_NAME_PASSPHRASE, "Key passphrase: " },
+    { NULL,                               NULL}
+};
+
 /**
  * This function generates a prompt to the specified instance of guac_client
  * for the credential specified in the cred_name parameter, which should
@@ -74,19 +103,15 @@ static void guac_ssh_get_credential(guac_client *client, char* cred_name) {
 
     guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
     
-    /* If the client does not support the "required" instruction, just return. */
-    if (!guac_client_owner_supports_required(client))
-        return;
-    
     /* Lock the terminal thread while prompting for the credential. */
-    pthread_mutex_lock(&(ssh_client->term_channel_lock));
+    pthread_mutex_lock(&(ssh_client->ssh_credential_lock));
     
     /* Let the owner know what we require. */
     guac_client_owner_send_required(client, (const char* []) {cred_name, NULL});
     
     /* Wait for the response, and then unlock the thread. */
-    pthread_cond_wait(&(ssh_client->ssh_credential_cond), &(ssh_client->term_channel_lock));
-    pthread_mutex_unlock(&(ssh_client->term_channel_lock));
+    pthread_cond_wait(&(ssh_client->ssh_credential_cond), &(ssh_client->ssh_credential_lock));
+    pthread_mutex_unlock(&(ssh_client->ssh_credential_lock));
     
 }
 
@@ -110,8 +135,20 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
     guac_common_ssh_user* user;
 
     /* Get username */
-    while (settings->username == NULL)
-        guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_USERNAME);
+    while (settings->username == NULL) {
+        
+        /* Client owner supports required instruction, so send prompt(s) that way. */
+        if (guac_client_owner_supports_required(client)) {
+            guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_USERNAME);
+        }
+        
+        /* Fall back to terminal prompting. */
+        else {
+            settings->username = guac_terminal_prompt(ssh_client->term,
+                "Login as: ", true);
+        }
+
+    }
     
     /* Create user object from username */
     user = guac_common_ssh_create_user(settings->username);
@@ -135,8 +172,18 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
                     "Re-attempting private key import (WITH passphrase)");
 
             /* Prompt for passphrase if missing */
-            while (settings->key_passphrase == NULL)
-                guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_PASSPHRASE);
+            while (settings->key_passphrase == NULL) {
+                
+                /* Send prompt via required instruction, if supported */
+                if (guac_client_owner_supports_required(client))
+                    guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_PASSPHRASE);
+                
+                /* Fall back to terminal prompt */
+                else
+                    settings->key_passphrase = guac_terminal_prompt(ssh_client->term,
+                        "Key passphrase: ", true);
+                
+            }
 
             /* Reattempt import with passphrase */
             if (guac_common_ssh_user_import_key(user,
@@ -285,6 +332,7 @@ void* ssh_client_thread(void* data) {
     }
 
     pthread_mutex_init(&ssh_client->term_channel_lock, NULL);
+    pthread_mutex_init(&ssh_client->ssh_credential_lock, NULL);
     pthread_cond_init(&(ssh_client->ssh_credential_cond), NULL);
 
     /* Open channel for terminal */

src/protocols/ssh/ssh.h

@@ -90,6 +90,12 @@ typedef struct guac_ssh_client {
      */
     pthread_mutex_t term_channel_lock;
     
+    /**
+     * Lock that will be locked when retrieving required credentials from the
+     * user, and unlocked when those requirements are satisfied.
+     */
+    pthread_mutex_t ssh_credential_lock;
+    
     /**
      * Condition used when SSH client thread needs to wait for Guacamole
      * client to pass additional credentials before continuing the connection.

src/protocols/vnc/vnc.h

@@ -158,7 +158,10 @@ typedef struct guac_vnc_client {
     
     /**
      * A field to track flags related to retrieving required credentials
-     * from the client.
+     * from the client. These flags will be set when credentials are required
+     * that have not been provided, and cleared when those credentials are
+     * provided.  All flags are cleared at the start of the connection, and
+     * then set as the client determines which are required.
      *
      * @see GUAC_VNC_COND_FLAG_USERNAME
      * @see GUAC_VNC_COND_FLAG_PASSWORD