D0 Linux user mode programming

Programming Embedded Linux Applications for Linux

Objectives
  • Discover Linux and its development tools
  • Connect an embedded Linux system in a network
  • Review the Linux boot sequence
  • Mount a remote file system
  • Boot a remote Linux kernel
  • Program and Debug Linux applications
    • Network programming
    • Synchronous and asynchronous input-output
    • Multi-thread programming
    • Inter-process communications
Labs are conducted on target boards, that can be:
    Dual Cortex/A7-based "STM32MP15-DISCO" boards from STMicroelectronics.
    Quad Cortex/A9-based "SabreLite" boards from NXP.
    Quad Cortex/A53-based "imx8q-evk" boards from NXP.
Who should attend this course?
  • Engineers that must create embedded Linux applications
Prerequisite
  • Basic Linux user knowledge
  • Good C programming skills
Course environment
  • Printed course material (in English).
  • One Linux PC for two trainees.
  • One target platform for two trainees.

First Day
Linux overview
  • Linux
  • The various licenses used by Linux (GPL, LGPL, etc.)
  • Linux distributions
Linux for the user
  • The Linux filesystem
  • The Linux shell and scripts
  • The vi editor
  • Basic administration of a Linux system
Linux application development
  • Structure of Linux applications
    • The ELF file format
  • Linux development tools
    • Compiling
    • Documentation
    • Makefiles
    • Integrated Development Environments
  • Creating Linux libraries
    • Static libraries
    • Dynamic libraries
Exercise:  Writing a simple, static and dynamic, library
Second Day
Linux application debugging
  • Software Debug tools
    • Gdb
    • Memory management debug using dmalloc and efence
    • Runtime checks using valgrind
Exercise:  Debug an application and its libraries using gdbserver
Exercise:  Checking memory management using dmalloc and valgrind
Input-Output
  • Standard input-output
    • disk files
    • devices
  • Network programming
    • sockets
    • UDP and TCP protocols
  • Asynchronous input-output
    • Non-blocking I/O
    • Multiplexed (the select and poll APIs)
    • Notified I/O
    • Chained I/O (the aio POSIX API)
Exercise:  Programming a client-server application
Exercise:  Handle several parallel connections using asynchronous I/O
Tracing system calls
  • Trace system calls tools
    • Strace
    • Ltrace
Exercise:  Understanding Strace
Third Day
Time and signal handling
  • Signal handling
    • Signal types
    • Handling a signal
    • Functions usable in a signal handler
    • Signal masking and synchronous handling
  • User Timers
Exercise:  Manage timeouts using signals and timers
Multitask programming
  • Processes
    • The process concept
    • Processes and security
    • Process states
    • Process life-cycle : the "fork" and '"exec" calls
  • POSIX Threads
    • User and kernel threads
    • Thread programming
    • Mutexes and condition variables
    • Barriers
    • Thread-specific data
Exercise:  Managing several clients in parallel using fork
Exercise:  Create a remote server using fork and exec
Exercise:  Managing several clients in parallel using threads
Exercise:  Manage thread-static data in a library
Fourth Day
Memory management and Scheduling
  • Linux Memory Management
    • Virtual and physical memory
    • Pagination and protection
    • Swapping
    • Memory allocation
    • Caches
  • Scheduling in the Linux kernel
    • Context switches
    • The Completely Fair Scheduler
    • Scheduling groups
    • The real-time scheduler
    • Scheduling and SMP (Symmetrical Multi Processors)
Inter Process Communication
  • Inter Process Communication
    • File mapping of files and devices
    • Shared memory
    • Message queues
    • Pipes
  • Task synchronisation
    • Semaphore
    • Mutex
    • Signals
  • The System V IPC (optional, described in appendix)
Exercise:  Handle communications between processes in a multi-process client-server system
Exercise:  Setup timeouts to close dead connections on a server