1. Write a kernel module
2. Write a Makefile to automate the building process

• Take a snapshot before we begin.
• A basic kernel module that interacts with user level program
• ioctl_module.c
• ioctl_test.c
• Makefile
• After create_proc_entry(), a new file created. Where is it? Is it a real file?
• Add a new file operation: read()
• How do we know what parameters ioctl()/read() takes?
• Linux cross reference
  You can select a kernel version and look for definitions and references to a symbol
  e.g.: You might wanna check the symbols file_operations, _IOW, task_struct
• Add a new file operation: write()
• Operate on the file from shell
• Find the solution here

• Why do we need a Makefile
• Basic Syntax:
  • target: dependencies
  [tab] system command

Courtesy of Zhuoqun (Tom) Cheng.