From 5e4c7de5c73099df8842f9b93c57fe7d2dfaa7a8 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Mon, 27 Jul 2015 18:19:50 -0700
Subject: [PATCH] GUAC-298: Clarify function documentation and naming. Do not
 simply silently default to ISO8859-1 if encoding is invalid.

---
 src/protocols/vnc/client.c | 59 +++++++++++++++++++++++++-------------
 1 file changed, 39 insertions(+), 20 deletions(-)

diff --git a/src/protocols/vnc/client.c b/src/protocols/vnc/client.c
index 990c09f0..8d4ad8a7 100644
--- a/src/protocols/vnc/client.c
+++ b/src/protocols/vnc/client.c
@@ -222,42 +222,62 @@ static rfbClient* __guac_vnc_get_client(guac_client* client) {
 }
 
 /**
- * Configure the VNC clipboard reader/writer based on configured encoding.
- * Defaults to standard ISO8859-1 encoding if an invalid format is encountered.
+ * Sets the encoding of clipboard data exchanged with the VNC server to the
+ * encoding having the given name. If the name is left blank, or is invalid,
+ * the standard ISO8859-1 encoding will be used.
  *
- * @param guac_client_data
- *     Structure containing VNC client configuration.
+ * @param client
+ *     The client to set the clipboard encoding of.
  *
  * @param name
- *     Encoding name.
+ *     The name of the encoding to use for all clipboard data. Valid values
+ *     are: "ISO8859-1", "UTF-8", "UTF-16", "CP1252", or "".
  *
  * @return
- *     Returns 0 if standard ISO8859-1 encoding is used, 1 otherwise.
+ *     Zero if the chosen encoding is standard for VNC, or non-zero if the VNC
+ *     standard is being violated.
  */
-int __guac_client_configure_clipboard_encoding(vnc_guac_client_data* guac_client_data, const char* name) {
+static int guac_vnc_set_clipboard_encoding(guac_client* client,
+        const char* name) {
 
-    /* Configure clipboard reader/writer based on encoding name */
+    vnc_guac_client_data* guac_client_data =
+        (vnc_guac_client_data*) client->data;
+
+    /* Use ISO8859-1 if explicitly selected or blank */
+    if (name[0] == '\0' || strcmp(name, "ISO8859-1") == 0) {
+        guac_client_data->clipboard_reader = GUAC_READ_ISO8859_1;
+        guac_client_data->clipboard_writer = GUAC_WRITE_ISO8859_1;
+        return 0;
+    }
+
+    /* UTF-8 */
     if (strcmp(name, "UTF-8") == 0) {
         guac_client_data->clipboard_reader = GUAC_READ_UTF8;
         guac_client_data->clipboard_writer = GUAC_WRITE_UTF8;
         return 1;
     }
-    else if (strcmp(name, "UTF-16") == 0) {
+
+    /* UTF-16 */
+    if (strcmp(name, "UTF-16") == 0) {
         guac_client_data->clipboard_reader = GUAC_READ_UTF16;
         guac_client_data->clipboard_writer = GUAC_WRITE_UTF16;
         return 1;
     }
-    else if (strcmp(name, "CP-1252") == 0) {
+
+    /* CP1252 */
+    if (strcmp(name, "CP1252") == 0) {
         guac_client_data->clipboard_reader = GUAC_READ_CP1252;
         guac_client_data->clipboard_writer = GUAC_WRITE_CP1252;
         return 1;
     }
-    else {
-        /* Default to ISO8859-1 */
-        guac_client_data->clipboard_reader = GUAC_READ_ISO8859_1;
-        guac_client_data->clipboard_writer = GUAC_WRITE_ISO8859_1;
-        return 0;
-    }
+
+    /* If encoding unrecognized, warn and default to ISO8859-1 */
+    guac_client_log(client, GUAC_LOG_WARNING,
+            "Encoding '%s' is invalid. Defaulting to ISO8859-1.", name);
+
+    guac_client_data->clipboard_reader = GUAC_READ_ISO8859_1;
+    guac_client_data->clipboard_writer = GUAC_WRITE_ISO8859_1;
+    return 0;
 
 }
 
@@ -336,11 +356,10 @@ int guac_client_init(guac_client* client, int argc, char** argv) {
     guac_client_data->clipboard = guac_common_clipboard_alloc(GUAC_VNC_CLIPBOARD_MAX_LENGTH);
 
     /* Configure clipboard encoding */
-    if (__guac_client_configure_clipboard_encoding(
-            guac_client_data, argv[IDX_CLIPBOARD_ENCODING])) {
+    if (guac_vnc_set_clipboard_encoding(client, argv[IDX_CLIPBOARD_ENCODING]))
         guac_client_log(client, GUAC_LOG_INFO,
-                "Using non-standard VNC clipboard encoding: '%s'.", argv[IDX_CLIPBOARD_ENCODING]);
-    }
+                "Using non-standard VNC clipboard encoding: '%s'.",
+                argv[IDX_CLIPBOARD_ENCODING]);
 
     /* Ensure connection is kept alive during lengthy connects */
     guac_socket_require_keep_alive(client->socket);