From 7d31cb4d456185a951fc98276b1244039317a0a2 Mon Sep 17 00:00:00 2001
From: Daniel Drake <dsd@cs.manchester.ac.uk>
Date: Mon, 8 Oct 2007 16:55:50 +0100
Subject: [PATCH] Basic device discovery infrastructure

---
 libfprint/core.c        | 78 +++++++++++++++++++++++++++++++++++++++++
 libfprint/fp_internal.h |  9 +++++
 libfprint/fprint.h      |  7 ++++
 3 files changed, 94 insertions(+)

diff --git a/libfprint/core.c b/libfprint/core.c
index e7ee538..744424f 100644
--- a/libfprint/core.c
+++ b/libfprint/core.c
@@ -20,6 +20,7 @@
 #include <config.h>
 
 #include <glib.h>
+#include <usb.h>
 
 #include "fp_internal.h"
 
@@ -42,8 +43,85 @@ static void register_drivers(void)
 		register_driver(drivers[i]);
 }
 
+static const struct fp_driver *find_supporting_driver(struct usb_device *udev)
+{
+	GList *elem = registered_drivers;
+	
+	do {
+		const struct fp_driver *drv = elem->data;
+		const struct usb_id *id;
+
+		for (id = drv->id_table; id->vendor; id++)
+			if (udev->descriptor.idVendor == id->vendor &&
+					udev->descriptor.idProduct == id->product)
+				return drv;
+	} while (elem = g_list_next(elem));
+	return NULL;
+}
+
+API_EXPORTED struct fp_dscv_dev **fp_discover_devs(void)
+{
+	GList *tmplist = NULL;
+	struct fp_dscv_dev **list;
+	struct usb_device *udev;
+	struct usb_bus *bus;
+	int dscv_count = 0;
+
+	if (registered_drivers == NULL)
+		return NULL;
+
+	usb_find_busses();
+	usb_find_devices();
+
+	/* Check each device against each driver, temporarily storing successfully
+	 * discovered devices in a GList.
+	 *
+	 * Quite inefficient but excusable as we'll only be dealing with small
+	 * sets of drivers against small sets of USB devices */
+	for (bus = usb_get_busses(); bus; bus = bus->next)
+		for (udev = bus->devices; udev; udev = udev->next) {
+			const struct fp_driver *drv = find_supporting_driver(udev);
+			struct fp_dscv_dev *ddev;
+			if (!drv)
+				continue;
+			ddev = g_malloc0(sizeof(*ddev));
+			ddev->drv = drv;
+			ddev->udev = udev;
+			tmplist = g_list_prepend(tmplist, (gpointer) ddev);
+			dscv_count++;
+		}
+
+	/* Convert our temporary GList into a standard NULL-terminated pointer
+	 * array. */
+	list = g_malloc(sizeof(*list) * (dscv_count + 1));
+	if (dscv_count > 0) {
+		GList *elem = tmplist;
+		int i = 0;
+		do {
+			list[i++] = elem->data;
+		} while (elem = g_list_next(elem));
+	}
+	list[dscv_count] = NULL; /* NULL-terminate */
+
+	g_list_free(tmplist);
+	return list;
+}
+
+API_EXPORTED void fp_dscv_devs_free(struct fp_dscv_dev **devs)
+{
+	int i;
+	if (!devs)
+		return;
+
+	for (i = 0; devs[i]; i++)
+		g_free(devs[i]);
+	g_free(devs);
+}
+
 API_EXPORTED int fp_init(void)
 {
+	usb_init();
 	register_drivers();
 	return 0;
 }
+
diff --git a/libfprint/fp_internal.h b/libfprint/fp_internal.h
index 19f5ee5..3b6ab05 100644
--- a/libfprint/fp_internal.h
+++ b/libfprint/fp_internal.h
@@ -22,6 +22,10 @@
 
 #include <stdint.h>
 
+#include <usb.h>
+
+#include <fprint.h>
+
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof(*a))
 
 struct usb_id {
@@ -38,5 +42,10 @@ struct fp_driver {
 
 extern const struct fp_driver upekts_driver;
 
+struct fp_dscv_dev {
+	struct usb_device *udev;
+	const struct fp_driver *drv;
+};
+
 #endif
 
diff --git a/libfprint/fprint.h b/libfprint/fprint.h
index 889dda7..5be5311 100644
--- a/libfprint/fprint.h
+++ b/libfprint/fprint.h
@@ -20,6 +20,13 @@
 #ifndef __FPRINT_H__
 #define __FPRINT_H__
 
+/* structs that applications are not allowed to peek into */
+struct fp_dscv_dev;
+
+/* Device discovery */
+struct fp_dscv_dev **fp_discover_devs(void);
+void fp_dscv_devs_free(struct fp_dscv_dev **devs);
+
 int fp_init(void);
 
 #endif