What driver is behind a certain device file?

Question

Given a device file, say /dev/sdb, is it possible to determine what driver is behind it?

Specifically, I want to determine what driver my storage devices are using. fdisk -l lists 2 devices: /dev/sda and /dev/sdb. One is a SATA hard drive and the other is a USB Mass Storage device - actually an SD card.

How do I determine, programmatically, which is which?

I am writing a piece of software, and I want to protect the beginner from obliterating their hard drives, whilst allowing them to obliterate their SD cards.

Answer 1

Run udevadm info -a -n /dev/sda and parse the output. You'll see lines like

DRIVERS=="ahci"

for a SATA disk using the ahci driver, or

DRIVERS=="usb-storage"

for an USB-connected device. You'll also be able to display vendor and model names for confirmation. Also,

ATTR{removable}=="1"

is present on removable devices.

All of this information can also be obtained through /sys (in fact, that's where udevadm goes to look), but the /sys interface changes from time to time, so parsing udevadm is more robust in the long term.