Implement PC/SC compatibility helpers for non-PCSCLite builds

Linux and MacOS are both supported by pcsc-lite, but unfortunately there
is no pcsc-lite package for MSYS2 and Windows does not provide the
reader.h header.

src/pcsc.c

@@ -22,7 +22,12 @@
 #include "pcsc.h"
 
 #include <winscard.h>
+#ifdef USE_PCSCLITE
+// Only PCSCLite provides reader.h
 #include <reader.h>
+#endif
+// Compatibility helpers must not conflict with winscard.h or reader.h
+#include "pcsc_compat.h"
 
 #include <stdbool.h>
 #include <stdint.h>
@@ -37,16 +42,6 @@
 #include <winsock.h>
 #endif
 
-#ifndef USE_PCSCLITE
-// Only PCSCLite provides pcsc_stringify_error()
-static const char* pcsc_stringify_error(unsigned int result)
-{
-	static char str[16];
-	snprintf(str, sizeof(str), "0x%08X", result);
-	return str;
-}
-#endif
-
 struct pcsc_t {
 	SCARDCONTEXT context;
 
@@ -60,23 +55,19 @@ struct pcsc_t {
 
 struct pcsc_reader_features_t {
 	// Populated by SCardControl(CM_IOCTL_GET_FEATURE_REQUEST)
-	uint8_t buf[MAX_BUFFER_SIZE];
+	uint8_t buf[PCSC_MAX_BUFFER_SIZE];
 	DWORD buf_len;
 
 	// Populated by SCardControl(IFD_PIN_PROPERTIES)
 	PIN_PROPERTIES_STRUCTURE pin_properties;
 	DWORD pin_properties_len;
 
 	// Populated by SCardControl(IFD_DISPLAY_PROPERTIES)
-	struct {
-		uint16_t wLcdMaxCharacters;
-		uint16_t wLcdMaxLines;
-	} __attribute__((packed))
-	display_properties;
+	DISPLAY_PROPERTIES_STRUCTURE display_properties;
 	DWORD display_properties_len;
 
 	// Populated by SCardControl(GET_TLV_PROPERTIES)
-	uint8_t properties[MAX_BUFFER_SIZE];
+	uint8_t properties[PCSC_MAX_BUFFER_SIZE];
 	DWORD properties_len;
 };
 
@@ -248,7 +239,7 @@ static int pcsc_reader_populate_features(struct pcsc_reader_t* reader)
 		++pcsc_tlv;
 	}
 
-	r = pcsc_reader_get_feature(reader, FEATURE_IFD_PIN_PROPERTIES, &control_code);
+	r = pcsc_reader_get_feature(reader, PCSC_FEATURE_IFD_PIN_PROPERTIES, &control_code);
 	if (r < 0) {
 		r = -6;
 		goto exit;
@@ -277,7 +268,7 @@ static int pcsc_reader_populate_features(struct pcsc_reader_t* reader)
 		}
 	}
 
-	r = pcsc_reader_get_feature(reader, FEATURE_IFD_DISPLAY_PROPERTIES, &control_code);
+	r = pcsc_reader_get_feature(reader, PCSC_FEATURE_IFD_DISPLAY_PROPERTIES, &control_code);
 	if (r < 0) {
 		r = -9;
 		goto exit;
@@ -306,7 +297,7 @@ static int pcsc_reader_populate_features(struct pcsc_reader_t* reader)
 		}
 	}
 
-	r = pcsc_reader_get_feature(reader, FEATURE_GET_TLV_PROPERTIES, &control_code);
+	r = pcsc_reader_get_feature(reader, PCSC_FEATURE_GET_TLV_PROPERTIES, &control_code);
 	if (r < 0) {
 		r = -12;
 		goto exit;

src/pcsc_compat.h

@@ -0,0 +1,92 @@
+/**
+ * @file pcsc_compat.h
+ * @brief PC/SC compatibility helpers
+ *
+ * Copyright (c) 2024 Leon Lynch
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef PCSC_COMPAT_H
+#define PCSC_COMPAT_H
+
+#include <sys/cdefs.h>
+#include <stdint.h>
+#include <stdio.h>
+
+__BEGIN_DECLS
+
+#if !defined(SCARD_CTL_CODE) && defined(CTL_CODE)
+// Not all implementations define SCARD_CTL_CODE but it can be derived
+// from CTL_CODE when available
+#define SCARD_CTL_CODE(code) CTL_CODE(FILE_DEVICE_SMARTCARD, (code), METHOD_BUFFERED, FILE_ANY_ACCESS)
+#endif
+
+// See PC/SC Part 10 Rev 2.02.09, 2.2
+#ifndef CM_IOCTL_GET_FEATURE_REQUEST
+#define CM_IOCTL_GET_FEATURE_REQUEST SCARD_CTL_CODE(3400)
+#endif
+
+// See PC/SC Part 10 Rev 2.02.09, 2.3
+#define PCSC_FEATURE_IFD_PIN_PROPERTIES         (0x0A) ///< Interface Device (IFD) PIN handling properties
+#define PCSC_FEATURE_IFD_DISPLAY_PROPERTIES     (0x11) ///< Interface Device (IFD) display properties
+#define PCSC_FEATURE_GET_TLV_PROPERTIES         (0x12) ///< Interface Device (IFD) properties in Tag-Length-Value (TLV) form
+
+#ifdef USE_PCSCLITE
+
+#define PCSC_MAX_BUFFER_SIZE (MAX_BUFFER_SIZE)
+
+#else // !USE_PCSCLITE
+
+#define PCSC_MAX_BUFFER_SIZE (264)
+
+// See PC/SC Part 10 Rev 2.02.09, 2.2
+typedef struct
+{
+	uint8_t tag;
+	uint8_t length;
+	uint32_t value;
+} __attribute__((packed))
+PCSC_TLV_STRUCTURE;
+
+// See PC/SC Part 10 Rev 2.02.09, 2.6.8
+typedef struct {
+	uint16_t wLcdLayout;
+	uint8_t bEntryValidationCondition;
+	uint8_t bTimeOut2;
+} __attribute__((packed))
+PIN_PROPERTIES_STRUCTURE;
+
+// Only PCSCLite provides pcsc_stringify_error()
+static const char* pcsc_stringify_error(unsigned int result)
+{
+	static char str[16];
+	snprintf(str, sizeof(str), "0x%08X", result);
+	return str;
+}
+
+#endif // USE_PCSCLITE
+
+// PCSCLite does not provide DISPLAY_PROPERTIES_STRUCTURE
+// See PC/SC Part 10 Rev 2.02.09, 2.6.9
+typedef struct {
+	uint16_t wLcdMaxCharacters;
+	uint16_t wLcdMaxLines;
+} __attribute__((packed))
+DISPLAY_PROPERTIES_STRUCTURE;
+
+__END_DECLS
+
+#endif