System Programming for Embedded Linux

Developing for embedded Linux

• The tool-chain: choosing, installing and testing
• The Linux kernel: customising and cross-compiling
• The bootloader & root file system: final steps to having a working target board
• Embedded development using Eclipse for cross-compiling and remote debug
• Application program interfaces: the POSIX standard
• Open source licenses: GPL/LGPL, BSD, etc.

Files and devices

• Files and file-related API: waiting for several things to happen with select() and poll()
• Devices: everything is a file. Interfacing with a simple device driver. Using the ioctl() function to access device-specific operations
• Interacting with the kernel through /proc & /sys: an example using gpiolib

Processes

• Process life cycle: fork(), exit() & exec()
• Scheduling: real-time & non-real-time policies; setting priority and niceness

Memory

• Virtual memory and its consequences
• Allocating from the heap and stack
• Mapping memory using mmap

Signals

• Standard and real-time signals
• Writing robust signal handlers
• Signal masks and how to handle signals synchronously

Inter-process communication

• Pipes
• Shared memory
• Semaphores
• Messages queues
• Sockets: internet and UNIX (local). Stream and datagram connections

POSIX Threads

• Thread life cycle: pthread_create(), pthread_exit(), pthread_join()
• Scheduling threads: real-time and non-real-time
• The thread stack and how to set the stack size

Thread synchronisation

• Synchronisation using mutexes: priority inversion and priority inheritance
• Condition variables: producer and consumer threads
• Thread cancellation and clean-up operators
• Signals and threads

Time and timers

• Timer accuracy: high-resolution timers, POSIX clocks and timers
• Measuring time
• Periodic tasks