GUACAMOLE-649: Add support for setting LANG environment variable via SSH.

src/protocols/ssh/settings.c

@@ -60,6 +60,7 @@ const char* GUAC_SSH_CLIENT_ARGS[] = {
     "backspace",
     "terminal-type",
     "scrollback",
+    "locale",
     NULL
 };
 
@@ -238,6 +239,14 @@ enum SSH_ARGS_IDX {
      */
     IDX_SCROLLBACK,
 
+    /**
+     * The locale that should be forwarded to the remote system via the LANG
+     * environment variable. By default, no locale is forwarded. This setting
+     * will only have an effect if the SSH server allows the LANG environment
+     * variable to be set.
+     */
+    IDX_LOCALE,
+
     SSH_ARGS_COUNT
 };
 
@@ -396,6 +405,11 @@ guac_ssh_settings* guac_ssh_parse_args(guac_user* user,
         guac_user_parse_args_string(user, GUAC_SSH_CLIENT_ARGS, argv,
                 IDX_TERMINAL_TYPE, "linux");
 
+    /* Read locale */
+    settings->locale =
+        guac_user_parse_args_string(user, GUAC_SSH_CLIENT_ARGS, argv,
+                IDX_LOCALE, NULL);
+
     /* Parsing was successful */
     return settings;
 
@@ -435,6 +449,9 @@ void guac_ssh_settings_free(guac_ssh_settings* settings) {
     /* Free terminal emulator type. */
     free(settings->terminal_type);
 
+    /* Free locale */
+    free(settings->locale);
+
     /* Free overall structure */
     free(settings);
 

src/protocols/ssh/settings.h

@@ -248,6 +248,12 @@ typedef struct guac_ssh_settings {
      */
     char* terminal_type;
 
+    /**
+     * The locale that should be forwarded to the remote system via the LANG
+     * environment variable.
+     */
+    char* locale;
+
 } guac_ssh_settings;
 
 /**

src/protocols/ssh/ssh.c

@@ -320,6 +320,17 @@ void* ssh_client_thread(void* data) {
         return NULL;
     }
 
+    /* Forward specified locale */
+    if (settings->locale != NULL) {
+        if (libssh2_channel_setenv(ssh_client->term_channel, "LANG",
+                    settings->locale)) {
+            guac_client_abort(client, GUAC_PROTOCOL_STATUS_UPSTREAM_ERROR,
+                    "Unable to forward locale: SSH server refused to set "
+                    "\"LANG\" environment variable.");
+            return NULL;
+        }
+    }
+
     /* If a command is specified, run that instead of a shell */
     if (settings->command != NULL) {
         if (libssh2_channel_exec(ssh_client->term_channel, settings->command)) {