Mastering Embedded Linux Programming - Second Edition

A better way of managing device nodes

Creating device nodes statically with mknod is quite hard work and inflexible. There are other ways to create device nodes automatically on demand:

• devtmpfs: This is a pseudo filesystem that you mount over /dev at boot time. The kernel populates it with device nodes for all the devices that the kernel currently knows about, and it creates nodes for new devices as they are detected at runtime. The nodes are owned by root and have default permissions of 0600. Some well-known device nodes, such as /dev/null and /dev/random, override the default to 0666. To see exactly how this is done, take a look at the Linux source file: drivers/char/mem.c and see how struct memdev is initialized.
• mdev: This is a BusyBox ...