Mastering Embedded Linux Programming - Second Edition

Getting information from sysfs

You can define sysfs in a pedantic way as a representation of kernel objects, attributes, and relationships. A kernel object is a directory, an attribute is a file, and a relationship is a symbolic link from one object to another. From a more practical point of view, since the Linux device driver model represents all devices and drivers as kernel objects, you can see the kernel's view of the system laid out before you by looking in /sys, as shown here:

# ls /sysblock     class     devices   fs        modulebus       dev       firmware  kernel    power

In the context of discovering information about devices and drivers, I will look at three of these directories: devices, class, and block.