Mastering Embedded Linux Programming - Second Edition

An example using mdev

While mdev is a bit more complex to set up, it does allow you to modify the permissions of device nodes as they are created. You begin by running mdev with the -s option, which causes it to scan the /sys directory looking for information about current devices. From this information, it populates the /dev directory with the corresponding nodes. If you want to keep track of new devices coming online and create nodes for them as well, you need to make mdev a hot plug client by writing to /proc/sys/kernel/hotplug. These additions to /etc/init.d/rcS will achieve all of this:

#!/bin/shmount -t proc proc /procmount -t sysfs sysfs /sysmount -t devtmpfs devtmpfs /devecho /sbin/mdev > /proc/sys/kernel/hotplugmdev -s

The default ...