From 2a71c8fa82d206e34bc63e1852331912a560f411 Mon Sep 17 00:00:00 2001
From: Christian Prochaska <christian.prochaska@genode-labs.com>
Date: Tue, 5 Mar 2019 19:35:46 +0100
Subject: [PATCH] pcsc-lite: read vendor id and product id from USB device

Fixes #3211
---
 repos/libports/lib/mk/pcsc-lite.mk       |  2 +-
 repos/libports/run/smartcard.run         |  3 --
 repos/libports/src/lib/pcsc-lite/README  | 16 +++------
 repos/libports/src/lib/pcsc-lite/init.cc | 44 +++++++++++++-----------
 4 files changed, 28 insertions(+), 37 deletions(-)

diff --git a/repos/libports/lib/mk/pcsc-lite.mk b/repos/libports/lib/mk/pcsc-lite.mk
index 441154afa..d119cfdb8 100644
--- a/repos/libports/lib/mk/pcsc-lite.mk
+++ b/repos/libports/lib/mk/pcsc-lite.mk
@@ -2,7 +2,7 @@ PCSC_LITE_DIR := $(call select_from_ports,pcsc-lite)/src/lib/pcsc-lite
 
 include $(call select_from_repositories,lib/import/import-pcsc-lite.mk)
 
-LIBS += ccid libc
+LIBS += ccid libc libusb
 
 # find 'config.h'
 INC_DIR += $(REP_DIR)/src/lib/pcsc-lite
diff --git a/repos/libports/run/smartcard.run b/repos/libports/run/smartcard.run
index 3050d1824..520f6720d 100644
--- a/repos/libports/run/smartcard.run
+++ b/repos/libports/run/smartcard.run
@@ -112,9 +112,6 @@ append config {
 						<rom name="Info.plist"/>
 					</dir>
 				</dir>
-				<inline name="config.pcsc-lite">
-					<config vendor_id="} [smartcard_vendor_id] {" product_id="} [smartcard_product_id] {"/>
-				</inline>
 			</vfs>
 			<libc stdout="/dev/log" stderr="/dev/log" rtc="/dev/rtc"/>
 		</config>
diff --git a/repos/libports/src/lib/pcsc-lite/README b/repos/libports/src/lib/pcsc-lite/README
index 192f43826..c67823651 100644
--- a/repos/libports/src/lib/pcsc-lite/README
+++ b/repos/libports/src/lib/pcsc-lite/README
@@ -1,12 +1,4 @@
-The USB card reader to be used by an application must be configured with its
-vendor id and product id in a file '/config.pcsc-lite':
-
-<config>
-	<libc>
-		<vfs>
-			<inline name="config.pcsc-lite">
-				<config vendor_id="0xXXXX" product_id="0xXXXX"/>
-			</inline>
-		</vfs>
-	</libc>
-</config>
+The library uses the first (and currently the only) USB device reported by
+libusb as smartcard reader. The actual selection of the USB device to use is
+done by the USB driver according to its configured policy for the 'Usb' session
+with the label 'usb_device', which is used by libusb to access the device.
diff --git a/repos/libports/src/lib/pcsc-lite/init.cc b/repos/libports/src/lib/pcsc-lite/init.cc
index f1d69fabc..7d0c1610d 100644
--- a/repos/libports/src/lib/pcsc-lite/init.cc
+++ b/repos/libports/src/lib/pcsc-lite/init.cc
@@ -21,6 +21,9 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+/* libusb includes */
+#include <libusb.h>
+
 /* pcsc-lite includes */
 extern "C" {
 #include <debuglog.h>
@@ -42,39 +45,38 @@ struct Pcsc_lite_initializer
 			(void)DebugLogSetCategory(DEBUG_CATEGORY_APDU);
 		}
 
-		unsigned int vendor_id = 0x0000;
-		unsigned int product_id = 0x0000;
+		/*
+		 * Find out vendor id and product id of the connected USB device
+		 * and add it as reader.
+		 */
 
-		int fd = open("/config.pcsc-lite", O_RDONLY);
+		libusb_context *ctx = nullptr;
 
-		if (fd < 0) {
-			Genode::error("Could not open 'config.pcsc-lite'");
-			exit(1);
-		}
-		
-		char config[128];
-		if (read(fd, config, sizeof(config)) < 0) {
-			Genode::error("Could not read 'config.pcsc-lite'");
+		libusb_init(&ctx);
+
+		libusb_device **devs = nullptr;
+
+		if (libusb_get_device_list(ctx, &devs) < 1) {
+			Genode::error("Could not find a USB device.");
 			exit(1);
 		}
 
-		try {
+		struct libusb_device_descriptor device_descriptor;
 
-			Genode::Xml_node config_node(config);
-
-			vendor_id = config_node.attribute_value("vendor_id", 0U);
-			product_id = config_node.attribute_value("product_id", 0U);
-
-		} catch (...) {
-			Genode::error("Error parsing 'config.pcsc-lite'");
+		if (libusb_get_device_descriptor(devs[0], &device_descriptor) < 0) {
+			Genode::error("Could not read the device descriptor of the "
+			              "USB device.");
 			exit(1);
 		}
 
-		close(fd);
+		libusb_free_device_list(devs, 1);
+
+		libusb_exit(ctx);
 
 		char device[14];
 
-		snprintf(device, sizeof(device), "usb:%04x/%04x", vendor_id, product_id);
+		snprintf(device, sizeof(device), "usb:%04x/%04x",
+		         device_descriptor.idVendor, device_descriptor.idProduct);
 
 		RFAllocateReaderSpace(0);
 		(void)RFAddReader("CCID", 0, "/", device);