CODEWITHSUNDEEP
linuxusbkernel
upInCloud
upInCloud

Reputation: 1009

how to get 'device struct' from 'dev_t' in linux kernel programming?

I am quite new to kernel programming and I am following the tutorial given at : USB boot authentication

I want to get a 'device struct' of a USB drive. I have 'dev_t' instance of the USB device. Further, I want to check whether the device struct is a USB device or not. I am not able to figure out how to start...

Thanks

Upvotes: 4

Views: 5566

Answers (2)

asapello
asapello

Reputation: 46

As hiteshradia said dev_t is a device number (a major number and minor number). You can however use this along with the knowledge that it is for a block device to get access to the struct device associated with it. To do so, use struct block_device *bdget(dev_t) from linux/fs.h. From this you can use block_device->bd_part to get a struct hd_struct * for the device and finally use struct device *part_to_dev(struct hd_struct *) defined as a macro in linux/genhd.h.

Upvotes: 3

hiteshradia
hiteshradia

Reputation: 357

dev_t is only a device number which represents a /dev/sdb1 partition as seen from your link. It is not possible to get the underlying usb drive details using it.

In the link you provided there is section

if(udev->serial != NULL)
{
    if((strcmp(udev->serial, "3513001D97827E69")) == 0) /* Hard coded usb device serial here*/
    {
        key_dev_found = 1;
    }
}

where you can get usb device details and struct usb_device *udev

Upvotes: 1

Related Questions