Support different types in the parameter store

The test framework stores size_t and int32_t values in the parameter store
by converting them all to int. This is ok in practice, since we assume int
covers int32_t and we don't have test data larger than 2GB. But it's
confusing and error-prone. So make the parameter store a union, which allows
size_t values not to be potentially truncated and makes the code a little
clearer.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/host_test.function b/tests/suites/host_test.function
index 565ded3..59b18d2 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -28,7 +28,7 @@
  *              integer value.
  *
  * \param str   Input string.
- * \param value Pointer to int for output value.
+ * \param p_value Pointer to output value.
  *
  * \return      0 if success else 1
  */
@@ -203,7 +203,8 @@
  *
  * \return      0 for success else 1
  */
-static int convert_params(size_t cnt, char **params, int32_t *int_params_store)
+static int convert_params(size_t cnt, char **params,
+                          mbedtls_test_argument_t *int_params_store)
 {
     char **cur = params;
     char **out = params;
@@ -221,7 +222,7 @@
                 break;
             }
         } else if (strcmp(type, "int") == 0) {
-            if (verify_int(val, int_params_store) == 0) {
+            if (verify_int(val, &int_params_store->s32) == 0) {
                 *out++ = (char *) int_params_store++;
             } else {
                 ret = (DISPATCH_INVALID_TEST_DATA);
@@ -235,7 +236,7 @@
                     mbedtls_test_unhexify((unsigned char *) val, strlen(val),
                                           val, &len) == 0);
 
-                *int_params_store = len;
+                int_params_store->len = len;
                 *out++ = val;
                 *out++ = (char *) (int_params_store++);
             } else {
@@ -244,7 +245,7 @@
             }
         } else if (strcmp(type, "exp") == 0) {
             int exp_id = strtol(val, NULL, 10);
-            if (get_expression(exp_id, int_params_store) == 0) {
+            if (get_expression(exp_id, &int_params_store->s32) == 0) {
                 *out++ = (char *) int_params_store++;
             } else {
                 ret = (DISPATCH_INVALID_TEST_DATA);
@@ -463,7 +464,7 @@
     char buf[5000];
     char *params[50];
     /* Store for processed integer params. */
-    int32_t int_params[50];
+    mbedtls_test_argument_t int_params[50];
     void *pointer;
 #if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
     int stdout_fd = -1;