Define PSE and PPSE strings

These definitions can be used to stringify DF Name (field 84) as well as
by the TAL.

Author: leonlynch

src/emv_fields.h

@@ -28,6 +28,10 @@
 
 __BEGIN_DECLS
 
+// Payment System Environment strings
+#define EMV_PSE                                                 "1PAY.SYS.DDF01" ///< Payment System Environment (PSE)
+#define EMV_PPSE                                                "2PAY.SYS.DDF01" ///< Proximity Payment System Environment (PPSE)
+
 // Application Priority Indicator
 // See EMV 4.4 Book 1, 12.2.3, table 13
 #define EMV_APP_PRIORITY_INDICATOR_MASK                         (0x0F)

src/emv_strings.c

@@ -222,6 +222,15 @@ int emv_tlv_get_info(
 				"Identifies the name of the Dedicated File (DF) as described "
 				"in ISO/IEC 7816-4";
 			info->format = EMV_FORMAT_B;
+			if ((tlv->length == strlen(EMV_PSE) && strncmp((const char*)tlv->value, EMV_PSE, strlen(EMV_PSE))) ||
+				(tlv->length == strlen(EMV_PPSE) && strncmp((const char*)tlv->value, EMV_PPSE, strlen(EMV_PPSE)))
+			) {
+				if (value_str_len > tlv->length) {
+					memcpy(value_str, tlv->value, tlv->length);
+					value_str[tlv->length] = 0;
+				}
+				return 0;
+			}
 			return emv_aid_get_string(tlv->value, tlv->length, value_str, value_str_len);
 
 		case EMV_TAG_87_APPLICATION_PRIORITY_INDICATOR:

src/emv_tal.c

@@ -50,7 +50,6 @@ int emv_tal_read_pse(
 )
 {
 	int r;
-	const uint8_t PSE[] = "1PAY.SYS.DDF01";
 	uint8_t fci[EMV_RAPDU_DATA_MAX];
 	size_t fci_len = sizeof(fci);
 	uint16_t sw1sw2;
@@ -66,8 +65,8 @@ int emv_tal_read_pse(
 	// SELECT Payment System Environment (PSE) Directory Definition File (DDF)
 	// See EMV 4.4 Book 1, 12.2.2
 	// See EMV 4.4 Book 1, 12.3.2
-	emv_debug_info("SELECT %s", PSE);
-	r = emv_ttl_select_by_df_name(ttl, PSE, sizeof(PSE) - 1, fci, &fci_len, &sw1sw2);
+	emv_debug_info("SELECT %s", EMV_PSE);
+	r = emv_ttl_select_by_df_name(ttl, EMV_PSE, strlen(EMV_PSE), fci, &fci_len, &sw1sw2);
 	if (r) {
 		emv_debug_trace_msg("emv_ttl_select_by_df_name() failed; r=%d", r);