Refactor emv_initiate_application_processing() to use emv_ctx_t

Note that emv_initiate_application_processing() will now clear the ICC
data list in case it was populated by a previous application selection
attempt.

Also, emv_initiate_application_processing() no longer has separate TLV
source lists as parameters and will instead search the TLV lists when
building the PDOL data for GET PROCESSING OPTIONS in this order:
* emv_ctx_t.params
* emv_ctx_t.config

In future, a more advanced per-AID configuration mechanism will impact
the above order.

src/emv.c

@@ -486,13 +486,7 @@ int emv_select_application(
 	return r;
 }
 
-int emv_initiate_application_processing(
-	struct emv_ttl_t* ttl,
-	struct emv_app_t* selected_app,
-	const struct emv_tlv_list_t* source1,
-	const struct emv_tlv_list_t* source2,
-	struct emv_tlv_list_t* icc
-)
+int emv_initiate_application_processing(struct emv_ctx_t* ctx)
 {
 	int r;
 	const struct emv_tlv_t* pdol;
@@ -501,15 +495,18 @@ int emv_initiate_application_processing(
 	size_t gpo_data_len;
 	struct emv_tlv_list_t gpo_output = EMV_TLV_LIST_INIT;
 
-	if (!ttl || !selected_app || !source1) {
-		emv_debug_trace_msg("ttl=%p, selected_app=%p, source1=%p, source2=%p", ttl, selected_app, source1, source2);
+	if (!ctx || !ctx->selected_app) {
+		emv_debug_trace_msg("ctx=%p, selected_app=%p", ctx, ctx->selected_app);
 		emv_debug_error("Invalid parameter");
 		return EMV_ERROR_INVALID_PARAMETER;
 	}
 
+	// Clear existing ICC data list to avoid ambiguity
+	emv_tlv_list_clear(&ctx->icc);
+
 	// Process PDOL, if available
 	// See EMV 4.4 Book 3, 10.1
-	pdol = emv_tlv_list_find_const(&selected_app->tlv_list, EMV_TAG_9F38_PDOL);
+	pdol = emv_tlv_list_find_const(&ctx->selected_app->tlv_list, EMV_TAG_9F38_PDOL);
 	if (pdol) {
 		int dol_data_len;
 		size_t gpo_data_offset;
@@ -545,8 +542,8 @@ int emv_initiate_application_processing(
 		r = emv_dol_build_data(
 			pdol->value,
 			pdol->length,
-			source1,
-			source2,
+			&ctx->params,
+			&ctx->config,
 			gpo_data + gpo_data_offset,
 			&gpo_data_len
 		);
@@ -569,7 +566,7 @@ int emv_initiate_application_processing(
 		gpo_data_len = 0;
 	}
 
-	r = emv_tal_get_processing_options(ttl, gpo_data, gpo_data_len, &gpo_output, NULL, NULL);
+	r = emv_tal_get_processing_options(ctx->ttl, gpo_data, gpo_data_len, &gpo_output, NULL, NULL);
 	if (r) {
 		emv_debug_trace_msg("emv_tal_get_processing_options() failed; r=%d", r);
 		if (r < 0) {
@@ -600,11 +597,11 @@ int emv_initiate_application_processing(
 	}
 
 	// Move application data to ICC data list
-	*icc = selected_app->tlv_list;
-	selected_app->tlv_list = EMV_TLV_LIST_INIT;
+	ctx->icc = ctx->selected_app->tlv_list;
+	ctx->selected_app->tlv_list = EMV_TLV_LIST_INIT;
 
 	// Append GPO output to ICC data list
-	r = emv_tlv_list_append(icc, &gpo_output);
+	r = emv_tlv_list_append(&ctx->icc, &gpo_output);
 	if (r) {
 		emv_debug_trace_msg("emv_tlv_list_append() failed; r=%d", r);
 
@@ -619,7 +616,6 @@ int emv_initiate_application_processing(
 	goto exit;
 
 error:
-	emv_tlv_list_clear(icc);
 	emv_tlv_list_clear(&gpo_output);
 exit:
 	return r;

src/emv.h

@@ -98,7 +98,8 @@ struct emv_ctx_t {
 	/**
 	 * @brief Currently selected application
 	 *
-	 * Populated by @ref emv_select_application().
+	 * Populated by @ref emv_select_application() and used by
+	 * @ref emv_initiate_application_processing().
 	 */
 	struct emv_app_t* selected_app;
 
@@ -261,29 +262,26 @@ int emv_select_application(
 /**
  * Initiate EMV application processing by assessing the Processing Options
  * Data Object List (PDOL) and performing GET PROCESSING OPTIONS.
+ *
+ * When building the PDOL data required for GET PROCESSING OPTIONS, this
+ * function will search the TLV lists in this order:
+ * - @ref emv_ctx_t.params
+ * - @ref emv_ctx_t.config
+ *
  * @note Upon success, this function will also move the selected application's
- *       TLV data to the ICC data output and append the output of
+ *       TLV data to the ICC data list and append the output of
  *       GET PROCESSING OPTIONS.
+ *
  * @remark See EMV 4.4 Book 3, 10.1
  * @remark See EMV 4.4 Book 4, 6.3.1
  *
- * @param ttl EMV Terminal Transport Layer context
- * @param selected_app Selected EMV application
- * @param source1 EMV TLV list used as primary source. Required.
- * @param source2 EMV TLV list used as secondary source. NULL to ignore.
- * @param icc ICC data output
+ * @param ctx EMV processing context
  *
  * @return Zero for success
  * @return Less than zero for errors. See @ref emv_error_t
  * @return Greater than zero for EMV processing outcome. See @ref emv_outcome_t
  */
-int emv_initiate_application_processing(
-	struct emv_ttl_t* ttl,
-	struct emv_app_t* selected_app,
-	const struct emv_tlv_list_t* source1,
-	const struct emv_tlv_list_t* source2,
-	struct emv_tlv_list_t* icc
-);
+int emv_initiate_application_processing(struct emv_ctx_t* ctx);
 
 /**
  * Read EMV application data by performing READ RECORD for all records