GUACAMOLE-269: Remove unnecessary data structure and array size, and update comments.

src/protocols/ssh/ssh.c

@@ -192,8 +192,7 @@ void* ssh_client_thread(void* data) {
         return NULL;
     }
 
-    const int num_tty_opcodes = 1;
-    char ssh_ttymodes[(GUAC_SSH_TTY_OPCODE_SIZE * num_tty_opcodes) + 1];
+    char ssh_ttymodes[GUAC_SSH_TTYMODES_SIZE(1)];
 
     /* Set up screen recording, if requested */
     if (settings->recording_path != NULL) {
@@ -301,7 +300,7 @@ void* ssh_client_thread(void* data) {
     }
 
     /* Set up the ttymode array prior to requesting the PTY */
-    int ttymodeBytes = guac_ssh_ttymodes_init(ssh_ttymodes, sizeof(ssh_ttymodes),
+    int ttymodeBytes = guac_ssh_ttymodes_init(ssh_ttymodes,
             GUAC_SSH_TTY_OP_VERASE, settings->backspace, GUAC_SSH_TTY_OP_END);
     if (ttymodeBytes < 1)
         guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR, "Error storing TTY mode encoding \

src/protocols/ssh/ttymode.c

@@ -25,12 +25,11 @@
 #include <stdlib.h>
 #include <string.h>
 
-int guac_ssh_ttymodes_init(char opcode_array[], const int array_size,
-        ...) {
+int guac_ssh_ttymodes_init(char opcode_array[], ...) {
 
     /* Initialize the variable argument list. */
     va_list args;
-    va_start(args, array_size);
+    va_start(args, opcode_array);
 
     /* Initialize array pointer and byte counter. */
     char *current = opcode_array;
@@ -39,10 +38,6 @@ int guac_ssh_ttymodes_init(char opcode_array[], const int array_size,
     /* Loop through variable argument list. */
     while (true) {
        
-        /* Check to make sure we don't overrun array. */ 
-        if (bytes >= array_size)
-            return -1;
-
         /* Next argument should be an opcode. */
         char opcode = (char)va_arg(args, int);
         *(current++) = opcode;

src/protocols/ssh/ttymode.h

@@ -46,46 +46,27 @@
 #define GUAC_SSH_TTY_OP_VERASE 3
 
 /**
- * The SSH protocol attempts to configure the remote
- * terminal by sending pairs of opcodes and values, as
- * described in Section 8 of RFC 4254.  These are
- * comprised of a single byte opcode and a 4-byte
- * value.  This data structure stores a single opcode
- * and value pair.
+ * Macro for calculating the number of bytes required
+ * to pass a given number of opcodes, which calculates
+ * the size of the number of opcodes plus the single byte
+ * end opcode.
  */
-typedef struct guac_ssh_ttymode {
-
-    /**
-     * The single byte opcode for defining the TTY
-     * encoding setting for the remote terminal.  The
-     * stadard codes are defined in Section 8 of
-     * the SSH RFC (4254).
-     */
-    char opcode;
-
-    /**
-     * The four byte value of the setting for the
-     * defined opcode.
-     */
-    uint32_t value;
-
-} guac_ssh_ttymode;
+#define GUAC_SSH_TTYMODES_SIZE(num_opcodes) ((GUAC_SSH_TTY_OPCODE_SIZE * num_opcodes) + 1)
 
 /**
  * Opcodes and value pairs are passed to the SSH connection
  * in a single array, beginning with the opcode and followed
  * by a four byte value, repeating until the end opcode is
- * encountered.  This function takes the array, the array
- * size, and a variable number of opcode and value pair
- * arguments and puts them in the array expected by the
- * SSH connection.
+ * encountered.  This function takes the array that will be
+ * sent and a variable number of opcode and value pair
+ * arguments and places the opcode and values in the array
+ * as expected by the SSH connection.
  *
  * @param opcode_array
  *     Pointer to the opcode array that will ultimately
- *     be passed to the SSH connection.
- *
- * @param array_size
- *     Size, in bytes, of the array.
+ *     be passed to the SSH connection.  The array must
+ *     be size to handle 5 bytes for each opcode and value
+ *     pair, plus one additional byte for the end opcode.
  *
  * @params ...
  *     A variable number of opcode and value pairs
@@ -95,7 +76,6 @@ typedef struct guac_ssh_ttymode {
  *     Number of bytes written to the array, or zero
  *     if a failure occurs.
  */
-int guac_ssh_ttymodes_init(char opcode_array[], const int array_size,
-        ...);
+int guac_ssh_ttymodes_init(char opcode_array[], ...);
 
 #endif