Summary

• Nearly all drivers will need to expose their services to applications run by the user.
• To allow applications to interact with a kernel driver, the driver needs to cross the barrier that exists between user space code and kernel code. A driver written using the I/O Kit framework achieves this by implementing a class that derives from the IOUserClient class.
• Applications can iterate loaded kernel drivers or can install a callback function to receive notifications when drivers are loaded and unloaded.
• The I/O Kit provides several functions that allow a user application to request services provided by a driver, including by reading and writing driver properties, or by establishing a connection to the driver and sending control requests to the driver over that connection.