The sysfs Filesystem

Short Description
sysfs is a feature of the Linux 2.6 kernel that al- … a kernel programming interface for exporting. these items via sysfs, and a user interface to …

Website: www.kernel.org | Filesize: 44kb

Content
The sysfs Filesystem
Patrick Mochel
mochel@digitalimplant.org
Abstract
sysfs is a feature of the Linux 2.6 kernel that allows
kernel code to export information to user
processes via an in-memory filesystem. The organization
of the filesystem directory hierarchy
is strict, and based the internal organization of
kernel data structures. The files that are created
in the filesystem are (mostly) ASCII files with
(usually) one value per file. These features ensure
that the information exported is accurate
and easily accessible, making sysfs one of the
most intuitive and useful features of the 2.6 kernel.
Introduction
sysfs is a mechanism for representing kernel
objects, their attributes, and their relationships
with each other. It provides two components:
a kernel programming interface for exporting
these items via sysfs, and a user interface to
view and manipulate these items that maps
back to the kernel objects which they represent.
The table below shows the mapping between
internel (kernel) constructs and their external
(userspace) sysfs mappings.
Internal External
Kernel Objects Directories
Object Attributes Regular Files
Object Relationships Symbolic Links
sysfs is a core piece of kernel infrastructure,
which means that it provides a relatively simple
interface to perform a simple…