Re: [PATCH] usbip: tools: Add usbip host driver availability check

[Shuah Khan <skhan@linuxfoundation.org>]

On 3/3/26 01:17, Zongmin Zhou wrote:
> From: Zongmin Zhou <zhouzongmin@kylinos.cn>
> 
> Currently, usbip_generic_driver_open() doesn't verify that the required
> kernel module (usbip-host or usbip-vudc) is actually loaded.
> The function returns success even when no driver is present,
> leading to usbipd daemon run success without driver loaded.

Doesn't usbip_generic_driver_open() try to refresh exported
device list and fail? It returns error if it can't find fetch
them.

usbipd starts and the when usbip_host is loaded it works correctly.
Doesn't it?

> 
> So add a check function to ensure usbip host driver has been loaded.
> 
> Signed-off-by: Zongmin Zhou <zhouzongmin@kylinos.cn>
> ---
>   tools/usb/usbip/libsrc/usbip_device_driver.c |  2 ++
>   tools/usb/usbip/libsrc/usbip_host_common.c   | 31 ++++++++++++++++++++
>   tools/usb/usbip/libsrc/usbip_host_common.h   |  2 ++
>   tools/usb/usbip/libsrc/usbip_host_driver.c   |  2 ++
>   4 files changed, 37 insertions(+)
> 
> diff --git a/tools/usb/usbip/libsrc/usbip_device_driver.c b/tools/usb/usbip/libsrc/usbip_device_driver.c
> index 927a151fa9aa..6da000fab26d 100644
> --- a/tools/usb/usbip/libsrc/usbip_device_driver.c
> +++ b/tools/usb/usbip/libsrc/usbip_device_driver.c
> @@ -147,6 +147,8 @@ static int usbip_device_driver_open(struct usbip_host_driver *hdriver)
>   struct usbip_host_driver device_driver = {
>   	.edev_list = LIST_HEAD_INIT(device_driver.edev_list),
>   	.udev_subsystem = "udc",
> +	.bus_type = "platform",

Why are we adding this here - user-space shouldn't need to
know what kind of driver this is?

> +	.drv_name = USBIP_DEVICE_DRV_NAME,

And the name?

>   	.ops = {
>   		.open = usbip_device_driver_open,
>   		.close = usbip_generic_driver_close,
> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.c b/tools/usb/usbip/libsrc/usbip_host_common.c
> index ca78aa368476..900370095b61 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_common.c
> +++ b/tools/usb/usbip/libsrc/usbip_host_common.c
> @@ -164,6 +164,31 @@ static void usbip_exported_device_destroy(struct list_head *devs)
>   	}
>   }
>   
> +/* Check if the usbip host driver is available in sysfs */
> +static int check_driver_available(struct usbip_host_driver *hdriver)
> +{
> +	char driver_path[SYSFS_PATH_MAX];
> +	struct stat st;
> +	int ret;
> +
> +	if (!hdriver->drv_name || !hdriver->bus_type)
> +		return 0;
> +
> +	//Check if the usbip-host or usbip-vudc driver directory exists in sysfs.
> +	snprintf(driver_path, sizeof(driver_path), "%s/%s/%s/%s/%s",
> +		SYSFS_MNT_PATH, SYSFS_BUS_NAME, hdriver->bus_type,
> +		SYSFS_DRIVERS_NAME, hdriver->drv_name);
> +
> +	ret = stat(driver_path, &st);
> +	if (ret == 0 && S_ISDIR(st.st_mode)) {
> +		dbg("driver '%s' is available", hdriver->drv_name);
> +		return 1;
> +	}
> +
> +	return 0;
> +}
> +
> +
>   int usbip_generic_driver_open(struct usbip_host_driver *hdriver)
>   {
>   	int rc;
> @@ -174,6 +199,12 @@ int usbip_generic_driver_open(struct usbip_host_driver *hdriver)
>   		return -1;
>   	}
>   
> +	//Check if the required driver is actually available.
> +	if (!check_driver_available(hdriver)) {
> +		err("please load '%s' kernel module", hdriver->drv_name);
> +		goto err;
> +	}
> +
>   	rc = refresh_exported_devices(hdriver);
>   	if (rc < 0)
>   		goto err;
> diff --git a/tools/usb/usbip/libsrc/usbip_host_common.h b/tools/usb/usbip/libsrc/usbip_host_common.h
> index f46967c0aa18..cf9bd60846cf 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_common.h
> +++ b/tools/usb/usbip/libsrc/usbip_host_common.h
> @@ -40,6 +40,8 @@ struct usbip_host_driver {
>   	/* list of exported device */
>   	struct list_head edev_list;
>   	const char *udev_subsystem;
> +	const char *bus_type;
> +	const char *drv_name;
>   	struct usbip_host_driver_ops ops;
>   };
>   
> diff --git a/tools/usb/usbip/libsrc/usbip_host_driver.c b/tools/usb/usbip/libsrc/usbip_host_driver.c
> index 573e73ec36bd..e8f9d2ee2497 100644
> --- a/tools/usb/usbip/libsrc/usbip_host_driver.c
> +++ b/tools/usb/usbip/libsrc/usbip_host_driver.c
> @@ -41,6 +41,8 @@ static int usbip_host_driver_open(struct usbip_host_driver *hdriver)
>   struct usbip_host_driver host_driver = {
>   	.edev_list = LIST_HEAD_INIT(host_driver.edev_list),
>   	.udev_subsystem = "usb",
> +	.bus_type = "usb",
> +	.drv_name = USBIP_HOST_DRV_NAME,

>   	.ops = {
>   		.open = usbip_host_driver_open,
>   		.close = usbip_generic_driver_close,

I need more to justify these changes.

thanks,
-- Shuah