From 470b1bc42bf53373ce678fc76bab9160a54d6881 Mon Sep 17 00:00:00 2001
From: Daniel Drake <dsd@gentoo.org>
Date: Sun, 4 May 2008 16:51:23 +0100
Subject: [PATCH] add functionality for querying and detaching kernel driver

---
 libusb/core.c           | 44 ++++++++++++++++++++++++++++++++++++++++++++
 libusb/libusb.h         |  6 +++++-
 libusb/libusbi.h        |  6 ++++++
 libusb/os/linux_usbfs.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/libusb/core.c b/libusb/core.c
index 2dce681..2225106 100644
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -716,6 +716,50 @@ API_EXPORTED int libusb_reset_device(libusb_device_handle *dev)
 	return usbi_backend->reset_device(dev);
 }
 
+/** \ingroup dev
+ * Determine if a kernel driver is active on an interface. If a kernel driver
+ * is active, you cannot claim the interface, and libusb will be unable to
+ * perform I/O.
+ *
+ * \param dev a device handle
+ * \param interface the interface to check
+ * \returns 0 if no kernel driver is active
+ * \returns 1 if a kernel driver is active
+ * \returns LIBUSB_ERROR code on failure
+ * \see libusb_detach_kernel_driver
+ */
+API_EXPORTED int libusb_kernel_driver_active(libusb_device_handle *dev,
+	int interface)
+{
+	usbi_dbg("interface %d", interface);
+	if (usbi_backend->kernel_driver_active)
+		return usbi_backend->kernel_driver_active(dev, interface);
+	else
+		return LIBUSB_ERROR_NOT_SUPPORTED;
+}
+
+/** \ingroup dev
+ * Detach a kernel driver from an interface. If successful, you will then be
+ * able to claim the interface and perform I/O.
+ *
+ * \param dev a device handle
+ * \param interface the interface to detach the driver from
+ * \returns 0 on success
+ * \returns LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
+ * \returns LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
+ * \returns another LIBUSB_ERROR code on other failure
+ * \see libusb_kernel_driver_active
+ */
+API_EXPORTED int libusb_detach_kernel_driver(libusb_device_handle *dev,
+	int interface)
+{
+	usbi_dbg("interface %d", interface);
+	if (usbi_backend->detach_kernel_driver)
+		return usbi_backend->detach_kernel_driver(dev, interface);
+	else
+		return LIBUSB_ERROR_NOT_SUPPORTED;
+}
+
 /** \ingroup lib
  * Initialize libusb. This function must be called before calling any other
  * libusb function.
diff --git a/libusb/libusb.h b/libusb/libusb.h
index 09401c2..5cce3fb 100644
--- a/libusb/libusb.h
+++ b/libusb/libusb.h
@@ -525,7 +525,8 @@ enum libusb_error {
 	LIBUSB_ERROR_BUSY = -5,
 	LIBUSB_ERROR_TIMEOUT = -6,
 	LIBUSB_ERROR_NO_MEM = -7,
-	LIBUSB_ERROR_OTHER = -8,
+	LIBUSB_ERROR_NOT_SUPPORTED = -8,
+	LIBUSB_ERROR_OTHER = -9,
 };
 
 /** \ingroup asyncio
@@ -663,6 +664,9 @@ int libusb_set_interface_alt_setting(libusb_device_handle *dev,
 int libusb_clear_halt(libusb_device_handle *dev, unsigned char endpoint);
 int libusb_reset_device(libusb_device_handle *dev);
 
+int libusb_kernel_driver_active(libusb_device_handle *dev, int interface);
+int libusb_detach_kernel_driver(libusb_device_handle *dev, int interface);
+
 /* async I/O */
 
 /** \ingroup asyncio
diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index bf4aa19..2f70053 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -284,6 +284,12 @@ struct usbi_os_backend {
 		unsigned char endpoint);
 	int (*reset_device)(struct libusb_device_handle *handle);
 
+	/* optional */
+	int (*kernel_driver_active)(struct libusb_device_handle *handle,
+		int interface);
+	int (*detach_kernel_driver)(struct libusb_device_handle *handle,
+		int interface);
+
 	void (*destroy_device)(struct libusb_device *dev);
 
 	int (*submit_transfer)(struct usbi_transfer *itransfer);
diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
index e67d7b6..40a32f1 100644
--- a/libusb/os/linux_usbfs.c
+++ b/libusb/os/linux_usbfs.c
@@ -516,6 +516,51 @@ static int op_reset_device(struct libusb_device_handle *handle)
 	return 0;
 }
 
+static int op_kernel_driver_active(struct libusb_device_handle *handle,
+	int interface)
+{
+	int fd = __device_handle_priv(handle)->fd;
+	struct usbfs_getdriver getdrv;
+	int r;
+
+	getdrv.interface = interface;
+	r = ioctl(fd, IOCTL_USBFS_GETDRIVER, &getdrv);
+	if (r) {
+		if (errno == ENODATA)
+			return 0;
+
+		usbi_err("get driver failed error %d errno %d", r, errno);
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return 1;
+}
+
+static int op_detach_kernel_driver(struct libusb_device_handle *handle,
+	int interface)
+{
+	int fd = __device_handle_priv(handle)->fd;
+	struct usbfs_ioctl command;
+	int r;
+
+	command.ifno = interface;
+	command.ioctl_code = IOCTL_USBFS_DISCONNECT;
+	command.data = NULL;
+
+	r = ioctl(fd, IOCTL_USBFS_IOCTL, &command);
+	if (r) {
+		if (errno == ENODATA)
+			return LIBUSB_ERROR_NOT_FOUND;
+		else if (errno == EINVAL)
+			return LIBUSB_ERROR_INVALID_PARAM;
+
+		usbi_err("detach failed error %d errno %d", r, errno);
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return 0;
+}
+
 static void op_destroy_device(struct libusb_device *dev)
 {
 	unsigned char *nodepath = __device_priv(dev)->nodepath;
@@ -1158,6 +1203,9 @@ const struct usbi_os_backend linux_usbfs_backend = {
 	.clear_halt = op_clear_halt,
 	.reset_device = op_reset_device,
 
+	.kernel_driver_active = op_kernel_driver_active,
+	.detach_kernel_driver = op_detach_kernel_driver,
+
 	.destroy_device = op_destroy_device,
 
 	.submit_transfer = op_submit_transfer,
-- 
2.7.4