380ad123a
Rob Landley
2005-09-23
Subject
We've gotten enough questions that are related to building systems rather than anything about busybox that I'm deeming it a FAQ, and answering it.
SOURCE BUG
This commit was genuinely broken at the time (not related to our build system): scripts/config/mkconfigs.c (2005-08-01 - 2006-10-05 arasi) uretilen bbconfigopts.h icine .config satirlarini kacissiz, ham newline'larla gömüyordu - gecerli C degildi, busybox'un kendi bb_mkdep araci bile parse edemiyordu (7d219aab7 ile duzeltildi, mkconfigs shell scripte cevrildi)
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docs/busybox.net/FAQ.html+107 -41
| @@ -8,6 +8,8 @@ about BusyBox. Some of the questions even have answers. If you | |
| have additions to this FAQ document, we would love to add them, | |
| <ol> | |
| + | <li><a href="#getting_started">How can I get started using BusyBox?</a> |
| + | <li><a href="#build_system">How do I build a BusyBox-based system?</a> |
| <li><a href="#kernel">Which Linux kernel versions are supported?</a> | |
| <li><a href="#arch">Which architectures does BusyBox run on?</a> | |
| <li><a href="#libc">Which C libraries are supported?</a> | |
| @@ -15,7 +17,6 @@ have additions to this FAQ document, we would love to add them, | |
| <li><a href="#bugs">I think I found a bug in BusyBox! What should I do?!</a> | |
| <li><a href="#job_control">Why do I keep getting "sh: can't access tty; job control | |
| turned off" errors? Why doesn't Control-C work within my shell?</a> | |
| - | <li><a href="#getting_started">How can I get started using BusyBox?</a> |
| <li><a href="#demanding">I demand that you to add <favorite feature> right now! How come | |
| you don't answer all my questions on the mailing list instantly? I demand | |
| that you help me with all of my problems <em>Right Now</em>!</a> | |
| @@ -31,46 +32,132 @@ have additions to this FAQ document, we would love to add them, | |
| </ol> | |
| - | |
| <hr /> | |
| <p> | |
| - | <h2><a name="kernel">Which Linux kernel versions are supported?</a></h2> |
| + | <h2><a name="getting_started">How can I get started using BusyBox?</a></h2> |
| + | <p> If you just want to try out busybox without installing it, download the |
| + | tarball, extract it, run "make allyesconfig", and then run "make". |
| + | </p> |
| + | <p> |
| + | This will create a busybox binary with all features enabled. To try |
| + | out a busybox applet, type "./busybox [appletname] [options]", for |
| + | example "./busybox ls -l" or "./busybox cat LICENSE". Type "./busybox" |
| + | to see a command list, and "busybox appletname --help" to see a brief |
| + | usage message for a given applet. |
| + | </p> |
| + | <p> |
| + | BusyBox uses the name it was invoked under to determine which applet is |
| + | being invoked. (Try "mv busybox ls" and then "./ls -l".) Installing |
| + | busybox consists of creating symlinks (or hardlinks) to the busybox |
| + | binary for each applet in busybox, and making sure these symlinks are in |
| + | the shell's command $PATH. ("make install" creates these symlinks, and |
| + | "make install-hardlinks" creates hardlinks instead.) The special applet |
| + | name "busybox" (or with any optional suffix, such as "busybox-static") |
| + | uses the first argument to determine which applet to run, as shown above. |
| + | </p> |
| + | <p> |
| + | BusyBox also has a feature called the "standalone shell", where the busybox |
| + | shell runs any built-in applets before checking the command path. This |
| + | feature is also enabled by "make allyesconfig", and to try it out run |
| + | the command line "PATH= ./busybox ash". This will blank your command path |
| + | and run busybox as your command shell, so the only commands it can find |
| + | (without an explicit path such as /bin/ls) are the built-in busybox ones. |
| + | This is another good way to see what's built into busybox. (Note that the |
| + | standalone shell is dependent on the existence of /proc/self/exe, so before |
| + | using it in a chroot environment you must mount /proc.) |
| + | </p> |
| + | <p> |
| + | To build a smaller busybox binary, run "make menuconfig" and disable the |
| + | features you don't need. (Or run "make allnoconfig" and then use |
| + | menuconfig to add just the features you need. Don't forget to recompile |
| + | with "make" once you've finished configuring.) |
| + | </p> |
| + | <hr/> |
| + | <p/> |
| + | <h2><a name="build_system">How do I build a BusyBox-based system?</a></h2> |
| + | <p> |
| + | BusyBox is a package that replaces a dozen standard packages, but it is |
| + | not by itself a complete bootable system. Building an entire Linux |
| + | distribution from source is a bit beyond the scope of this FAQ, but it |
| + | understandably keeps cropping up on the mailing list, so here are some |
| + | pointers. |
| + | </p> |
| + | <p> |
| + | Start by learning how to strip a working system down to the bare essentials |
| + | needed to run one or two commands, so you know what it is you actually |
| + | need. An excellent practical place to do |
| + | this is the <a href="http://www.tldp.org/HOWTO/Bootdisk-HOWTO/">Linux |
| + | BootDisk Howto</a>, or for a more theoretical approach try |
| + | <a href="http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html">From |
| + | PowerUp to Bash Prompt</a>. |
| + | </p> |
| + | <p> |
| + | To learn how to build a working Linux system entirely from source code, |
| + | the place to go is the <a href="http://www.linuxfromscratch.org">Linux |
| + | From Scratch</a> project. They have an entire book of step-by-step |
| + | instructions you can |
| + | <a href="http://www.linuxfromscratch.org/lfs/view/stable/">read online</a> |
| + | or |
| + | <a href="http://www.linuxfromscratch.org/lfs/downloads/stable/">download</a>. |
| + | Be sure to check out the other sections of their main page, including |
| + | Beyond Linux From Scratch, Hardened Linux From Scratch, their Hints |
| + | directory, and their LiveCD project. (They also have mailing lists which |
| + | are better sources of answers to Linux-system building questions than |
| + | the busybox list.) |
| + | </p> |
| <p> | |
| + | If you want an automated yet customizable system builder which produces |
| + | a BusyBox and uClibc based system, try |
| + | <a href="http://buildroot.uclibc.org">buildroot</a>, which is |
| + | another project by the maintainer of the uClibc and BusyBox projects |
| + | (Erik Andersen). Download the tarball, extract it, unset CC, make. |
| + | For more instructions, see the website. |
| + | </p> |
| - | Full functionality requires Linux 2.2.x or better. A large fraction of the |
| + | <hr /> |
| + | <p> |
| + | <h2><a name="kernel">Which Linux kernel versions are supported?</a></h2> |
| + | <p> |
| + | Full functionality requires Linux 2.4.x or better. (Earlier versions may |
| + | still work, but are no longer regularly tested.) A large fraction of the |
| code should run on just about anything. While the current code is fairly | |
| Linux specific, it should be fairly easy to port the majority of the code | |
| to support, say, FreeBSD or Solaris, or Mac OS X, or even Windows (if you | |
| are into that sort of thing). | |
| - | |
| - | |
| + | </p> |
| <hr /> | |
| <p> | |
| <h2><a name="arch">Which architectures does BusyBox run on?</a></h2> | |
| <p> | |
| - | |
| - | |
| BusyBox in general will build on any architecture supported by gcc. | |
| - | Kernel module loading for 2.2 and 2.4 Linux kernels is currently |
| + | Kernel module loading for 2.4 Linux kernels is currently |
| limited to ARM, CRIS, H8/300, x86, ia64, x86_64, m68k, MIPS, PowerPC, | |
| S390, SH3/4/5, Sparc, v850e, and x86_64 for 2.4.x kernels. | |
| - | |
| + | </p> |
| + | <p> |
| With 2.6.x kernels, module loading support should work on all architectures. | |
| - | |
| - | |
| + | </p> |
| <hr /> | |
| <p> | |
| <h2><a name="libc">Which C libraries are supported?</a></h2> | |
| <p> | |
| - | |
| - | |
| - | uClibc and glibc are supported. People have been looking at newlib and |
| - | dietlibc, but they are currently considered unsupported, untested, or |
| - | worse. Linux-libc5 is no longer supported. If you require a small C |
| - | library, you should probably use uClibc. |
| - | |
| - | |
| + | On Linux, BusyBox releases are tested against uClibc (0.9.27 or later) and |
| + | glibc (2.2 or later). Both should provide full functionality with busybox, |
| + | and if you find a bug we want to hear about it. |
| + | </p> |
| + | </p> |
| + | Linux-libc5 is no longer maintained (and has no known advantages over |
| + | uClibc), dietlibc is known to have numerous unfixed bugs, and klibc is |
| + | missing too many features to build BusyBox. If you require a small C |
| + | library for Linux, the busybox developers recommend uClibc. |
| + | </p> |
| + | <p> |
| + | Some BusyBox applets have been built and run under a combination |
| + | of newlib and libgloss (see |
| + | <a href="http://www.busybox.net/lists/busybox/2005-March/013759.html">this thread</a>). |
| + | This is still experimental, but may be supported in a future release. |
| + | </p> |
| <hr /> | |
| <p> | |
| <h2><a name="commercial">Can I include BusyBox as part of the software on my device?</a></h2> | |
| @@ -133,27 +220,6 @@ have additions to this FAQ document, we would love to add them, | |
| run your shell on a real console... | |
| - | <hr /> |
| - | <p> |
| - | <h2><a name="getting_started">How can I get started using BusyBox?</a></h2> |
| - | <p> |
| - | |
| - | An easy method to build your own basic BusyBox based system, is to |
| - | follow these simple steps: |
| - | <ul> |
| - | <li> Point your web browser <a href="http://buildroot.uclibc.org/">here</a> |
| - | <li> Download a copy of buildroot |
| - | <li> Unpack the tarball on your Linux system somewhere |
| - | <li> run 'make' and configure things to taste. |
| - | <li> run 'unset CC'. Some Linux systems (i.e. Gentoo) set 'CC' |
| - | in the system environment which messes up cross compiles. |
| - | <li> run 'make' |
| - | <li> go have lunch, drink a pop, call a friend, play a video game, etc |
| - | till it finishes downloading software and compiling things. |
| - | <li> You should now have a shiny new BusyBox based system. |
| - | </ul> |
| - | |
| - | |
| <hr /> | |
| <p> | |
| <h2><a name="demanding">I demand that you to add <favorite feature> right now! How come | |