Free Software for Embedded Systems. Mail: Web: University of Nice - Sophia Antipolis

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1 Free Software for Embedded Systems Mail: Web: University of Nice - Sophia Antipolis

2 Introduction We must start with something Free Electrons - Stéphane Lavirotte 2

3 Linux for Embedded Systems Linux for embedded systems Is used more and more In use in many devices Mobile Phones PDA (Personal Digital Equipment) Network Equipments Have a look to: Used in limited resources systems uclinux, uclibc, dietlib, Easy to include free software inside that products sqlite, samba, thttpd, Free Electrons - Stéphane Lavirotte 3

4 Development Phases Configuration First, choose which features to include in the system Kernel configuration Choose the tools and applications to include Build Need to recompile the entire system for the target: Kernel Libraries Applications Deployment Installation of files in a filesystem Transfer on the target and start the new system Free Electrons - Stéphane Lavirotte 4

5 System Components Component Boot Loader Kernel Kernel Modules File Systems Libraries Applications Boot Loader Kernel Kernel Modules Libraries Applications File System Free Electrons - Stéphane Lavirotte 5

6 About Free Software Linux is and Open Source Free Software Free Software provides 4 freedom to the user: See The freedom to use the program as it sees fit The freedom to study how the program works and adapt it to its own needs (Get the source code is a precondition). The freedom to redistribute copies to help others The freedom to improve the program, and distribute the improvements to the public so that the community can benefit from advanced (Get the source code is a precondition). Free Electrons - Stéphane Lavirotte 6

7 The GNU General Public License (GPL) Copyleft licenses rely on copyright law to require that any modified version remains free software. For more details Copyleft: The GNU GPL requires that modifications and derivative works are also under GPL: Applies only to software distributed Any program using GPL code (statically or dynamically linked) is regarded as an extension of this code and therefore under the GPL For more details FAQ GPL: Free Electrons - Stéphane Lavirotte 7

8 Free Applications and Embedded Systems A collection of Software Tools Free Electrons - Stéphane Lavirotte 8

9 glibc C Library made by GNU project LGPL License Designed for Performances Respect standards Portability Necessary for all GNU/Linux systems But too big for embedded systems About 1,5-2MB are necessary Sur IPaQ: 1,2MB pour la libc et 500KB pour la libm Sur i386: 1,3MB pour la libc et 150KB pour la libm Possible alternatives Free Electrons - Stéphane Lavirotte 9

10 uclibc C Library made by CodePoet Consulting LGPL License Now supported by MontaVista, TimeSys, Wind River Designed For small and tiny embedded systems With a maximum of functionalities Provides most needs Debian Woody completely ported using uclibc Small: about 4 times smaller than glibc arm glibc: 1700 KB (libc: 1.2 MB, libm: 500 KB) uclibc:. 400 KB (libuclibc: 300 KB, libm: 55KB) Free Electrons - Stéphane Lavirotte 10

11 Comparison glibc (GNU C Library) Done for its performance and the respect of standards The best for workstation machines and servers uclibc Highly compatible Made for embedded systems with a small storage capacity and memory The others: diet libc, newlib, klibc Most suitable for all small systems, or initramfs and init ramdisk Free Electrons - Stéphane Lavirotte 14

12 A Toolbox for the Target THE Toolbox Free Electrons - Stéphane Lavirotte 26

13 BusyBox BusyBox Consolidates most Unix utilities into a single executable A web server if also included! Small size Statically compiled with uclibc: less the 500KB Statically compiled with glibc: less than 1MB An excellent choice for: Initramfs or initrd with complexes scripts Embedded systems with small and medium-sized storage Easy to configure the wanted functionalities Free Electrons - Stéphane Lavirotte 27

14 BusyBox Commands addgroup, adduser, adjtimex, ar, arping, ash, awk, basename, bunzip2, bzcat, cal, cat, chgrp, chmod, chown, chroot, chvt, clear, cmp, cp, cpio, crond, crontab, cut, date, dc, dd, deallocvt, delgroup, deluser, devfsd, df, dirname, dmesg, dos2unix, dpkg, dpkgdeb, du, dumpkmap, dumpleases, echo, egrep, env, expr, false, fbset, fdflush, fdformat, fdisk, fgrep, find, fold, free, freeramdisk, fsck.minix, ftpget, ftpput, getopt, getty, grep, gunzip, gzip, halt, hdparm, head, hexdump, hostid, hostname, httpd, hush, hwclock, id, ifconfig, ifdown, ifup, inetd, init, insmod, install, ip, ipaddr, ipcalc, iplink, iproute, iptunnel, kill, killall, klogd, lash, last, length, linuxrc, ln, loadfont, loadkmap, logger, login, logname, logread, losetup, ls, lsmod, makedevs, md5sum, mesg, mkdir, mkfifo, mkfs.minix, mknod, mkswap, mktemp, modprobe, more, mount, msh, mt, mv, nameif, nc, netstat, nslookup, od, openvt, passwd, patch, pidof, ping, ping6, pipe_progress, pivot_root, poweroff, printf, ps, pwd, rdate, readlink, realpath, reboot, renice, reset, rm, rmdir, rmmod, route, rpm, rpm2cpio, runparts, rx, sed, seq, setkeycodes, sha1sum, sleep, sort, startstopdaemon, strings, stty, su, sulogin, swapoff, swapon, sync, sysctl, yslogd, tail, tar, tee, telnet, telnetd, test, tftp, time, top, touch, tr, traceroute, true, tty, udhcpc, udhcpd, umount, uname, uncompress, uniq, unix2dos, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, vlock, watch, watchdog, wc, wget, which, who, whoami, xargs, yes, zcat Free Electrons - Stéphane Lavirotte 28

15 Configuring BusyBox Get the latest stable version Configuring BusyBox (create a.config file): make defconfig To begin with BusyBox Configure Busybox with all the options (produce a huge system) make allnoconfig Unselect all the options Allow to include only wanted features (produce a small system) Same interface as the kernel configuration tool make menuconfig (texte) make xconfig (graphique) Possibility to configure the wanted commands and all the options and functionalities wanted for these commands Free Electrons - Stéphane Lavirotte 29

16 Compiling BusyBox When Cross-Compiling Choose the microprocessor architecture and the right crosscompiler in the Makefile (as for kernel) ARCH?= arm CROSS_COMPILE?= arm-linux-gnueabi- Add path to the cross-compiler in our PATH export PATH=/usr/local/arm/3.3.2/bin:$PATH BusyBox Compiling Make BusyBox Installing make install Just need to copy all files to the target filesystem cp -a _install/* /mnt/rootfs/ Free Electrons - Stéphane Lavirotte 30

17 Servers for the Target ssh, http, Free Electrons - Stéphane Lavirotte 33

18 Advantages of an Embedded Web Server Several devices need something to be able to configure it (for example, the network address) Gateway/ Modems, IP Camera, Printer, Advantages of an embedded Web Server No need to develop some specific drivers No need to develop a specific configuration application No need to support different OS Just need to develop some HTML pages (static or dynamic ones) to allow the configuration (with the power of java-script on client side) Reduce the hardware costs (no LCD screen, no need to have a lot of storage capabilities on device, ) Free Electrons - Stéphane Lavirotte 35

19 thttpd Tiny/Turbo/Throttling HTTP server: Simple Only implement the minimum of HTTP 1.1 protocol Small at all points of view 88KB for 2.25b version against 264KB for Apache Very low memory consumption (no fork) Portable Code Can compile on almost all Unix systems Very quick to answer Almost as fast as the complete servers Security Designed to protect Web servers from attacks Free Electrons - Stéphane Lavirotte 36

20 Other Embedded Web Servers BusyBox ( 9KB (BusyBox 1.5): includes CGI, authentication, and support for scripts (like php) Klone ( Can include dynamic page (in C/C++ <% code %> ) and compressed Only one executable (about 150KB) Boa ( Designed to be simple, fast and secured Lighthttpd ( Designed to manage high number of requests Free Electrons - Stéphane Lavirotte 37

21 Graphic Libraries for the Target Graphical Toolboxes Free Electrons - Stéphane Lavirotte 38

22 NanoX / Microwindows NanoX / Microwindows Graphical library running under Linux Framebuffer, X / Windows, SVGAlib, and some other graphical systems Advantages: Lisence: Mozilla Public License, allowing proprietary applications Very light (< 100KB) 2 APIs (C language) API Win32: allows Windows et Windows CE Naon-X API: small X server with an API of Xlib type Documentation of API, FAQs and Tutorials available Limitations Lack some support for themes Free Electrons - Stéphane Lavirotte 39

23 NanoX / Microwindows Free Electrons - Stéphane Lavirotte 40

24 MiniGUI MiniGUI Mature graphical toolbox Advantages Supported architectures: x86, arm, ppc, m68k, mips Support Linux / uclinux, ecos, some proprietary RT OS and Win32 Seams popular and used in many Asian devices Programming language: C About 700KB Limitations Needs a commercial license to create a product with Free Electrons - Stéphane Lavirotte 41

25 MiniGUI Terminals Industrial Tools Set Top Box Free Electrons - Stéphane Lavirotte 42

26 FLTK Fast Light ToolKit (pronounce «fulltick») Pronunciation: «fulltick» Advantages LGPL License Cross-platform: Unix X11, Windows et Max OS X Can create new applications in few minutes with the help of FLUID builder C++ Libraries Support for 3D graphical (OpenGL) Free Electrons - Stéphane Lavirotte 43

27 FLTK Free Electrons - Stéphane Lavirotte 44

28 Simple Direct media Layer Cross-platform multimedia library At the origin, created for video games programming Advantages Allow a very low level access: keyboard, mouse, joystick, sound, 3D display (via OpenGL) and 2D (via framebuffer) Now used for embedded systems Native C interface Several wrappers for many languages Many applications and demos available Free Electrons - Stéphane Lavirotte 45

29 SDL Free Electrons - Stéphane Lavirotte 46

30 DirectFB Advantages C library in user mode Designed for embedded systems Compact, powerful, flexible et easy to use Support for hardware acceleration (with fallback software for actions non hardware supported) Abstraction layer to entry possibilities Windowing system with transparency management Many applications and demos available Free Electrons - Stéphane Lavirotte 47

31 DirectFB Free Electrons - Stéphane Lavirotte 48

32 Qt Qt Embedded Advantages Same API as the desktop (easy to develop applications) Based on framebuffer (rather than X) with its own windowing system Can easily change Look and Feel Completely modular: so that, you can limit the size: Entre 1.7 et 4.1 MB compressed (3.6 et 9.0MB non compressed) Support for: arm, x86, mips, powerpc, windows ce Integrated with several Java VM Limitations Need a commercial license to create new products Free Electrons - Stéphane Lavirotte 49

33 Qt Free Electrons - Stéphane Lavirotte 50

34 GTK Projet GTK+ Advantages Exactly the same version as the desktop one C Library that we can include in several language Usable with X and DirectFB Based on Cairo for vector graphics Solutions for system without any FPU Limitations Important size with all libraries 4.4MB with DirectFB 13.4MB with X To see an application example: Free Electrons - Stéphane Lavirotte 51

35 GTK Free Electrons - Stéphane Lavirotte 52

36 Environments for Target A suite of standard applications Free Electrons - Stéphane Lavirotte 53

37 Opie. Open Palmtop Integrated Environment Based on Qt Embedded Advantages Based on framebuffer (rather than on X) Include an application suite for PDA Contacts, Calendar, (Personal Information Management) Multimedia applications for video and music playing Device configuration Misc: games, , Include beautiful icons and interfaces (themes) Limitations Lack a goo Web client (old Konqueror version) Free Electrons - Stéphane Lavirotte 54

38 Opie Free Electrons - Stéphane Lavirotte 55

39 Gnome Mobile. Gnome Mobile Advantages Huge community Free Electrons - Stéphane Lavirotte 56

40 Gnome Mobile Free Electrons - Stéphane Lavirotte 57

41 GPE. GPE Palmtop Environment Based on the GTK+ toolkit Advantages Based on X framebuffer X Easy to remotely display the screen of a PC Set of applications for PDA with LinPhone Standard GTK+ application can run with no or not much modifications Recognize handwriting on screen display Free Electrons - Stéphane Lavirotte 58

42 GPE Free Electrons - Stéphane Lavirotte 59