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| <h3>Frequently Asked Questions</h3> |
| |
| This is a collection of some of the more frequently asked questions |
| 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="#init">Busybox init isn't working!</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> |
| <li><a href="#commercial">Can I include BusyBox as part of the software on my device?</a> |
| <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="#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> |
| <li><a href="#helpme">I need help with BusyBox! What should I do?</a> |
| <li><a href="#contracts">I need you to add <favorite feature>! Are the BusyBox developers willing to |
| be paid in order to fix bugs or add in <favorite feature>? Are you willing to provide |
| support contracts?</a> |
| <li><a href="#external">Where can I find other small utilities since busybox does not include the features I want?</a></li> |
| <li><a href="#support">I think you guys are great and I want to help support your work!</a> |
| <li><a href="#optimize">I want to make busybox even smaller, how do I go about it?</a> |
| |
| |
| |
| </ol> |
| |
| <hr /> |
| <p> |
| <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 links are in |
| the shell's command $PATH. 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 (Erik Andersen). |
| Download the tarball, extract it, unset CC, make. |
| For more instructions, see the website. |
| </p> |
| |
| <hr /> |
| <p> |
| <h2><a name="init">Busybox init isn't working!</a></h2> |
| <p> |
| Build a statically linked version of the following "hello world" program |
| with your cross compiler toolchain. |
| </p> |
| <pre> |
| #include <stdio.h> |
| |
| int main(int argc, char *argv) |
| { |
| printf("Hello world!\n"); |
| sleep(999999999); |
| } |
| </pre> |
| |
| <p> |
| Now try to boot your device with an "init=" argument pointing to your |
| hello world program. Did you see the hello world message? Until you |
| do, don't bother messing with busybox init. |
| </p> |
| |
| <p> |
| Once you've got it working statically linked, try getting it to work |
| dynamically linked. Then read the FAQ entry before this one. |
| </p> |
| |
| <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 2.4 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> |
| 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> |
| |
| Yes. As long as you <a href="http://busybox.net/license.html">fully comply |
| with the generous terms of the GPL BusyBox license</a> you can ship BusyBox |
| as part of the software on your device. |
| |
| <br> |
| <a href="#support">Please consider sharing some of the money you make.</a> |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="bugs">I think I found a bug in BusyBox! What should I do?</a></h2> |
| <p> |
| |
| |
| <p> |
| |
| If you simply need help with using or configuring BusyBox, please submit a |
| detailed description of your problem to the BusyBox mailing list at <a |
| href="mailto:busybox@mail.busybox.net"> busybox@mail.busybox.net</a>. |
| Please do not send email to individual developers asking |
| for private help unless you are planning on paying for consulting services. |
| When we answer questions on the BusyBox mailing list, it helps everyone, |
| while private answers help only you... |
| |
| <p> |
| |
| The developers of BusyBox are busy people, and have only so much they can |
| keep in their brains at a time. As a result, bug reports sometimes get |
| lost when posted to the mailing list. To prevent your bug report from |
| getting lost, if you find a bug in BusyBox, please use the <a |
| href="http://bugs.busybox.net/">BusyBox Bug and Patch Tracking System</a> |
| to submit a detailed bug report. |
| |
| <p> |
| |
| The same also applies to patches... Regardless of whether your patch is a |
| bug fix or adds shiney new features, please post your patch to the <a |
| href="http://bugs.busybox.net/">BusyBox Bug and Patch Tracking System</a> |
| to make certain it is properly considered. |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="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></h2> |
| <p> |
| |
| Job control will be turned off since your shell can not obtain a controlling |
| terminal. This typically happens when you run your shell on /dev/console. |
| The kernel will not provide a controlling terminal on the /dev/console |
| device. Your should run your shell on a normal tty such as tty1 or ttyS0 |
| and everything will work perfectly. If you <em>REALLY</em> want your shell |
| to run on /dev/console, then you can hack your kernel (if you are into that |
| sortof thing) by changing drivers/char/tty_io.c to change the lines where |
| it sets "noctty = 1;" to instead set it to "0". I recommend you instead |
| run your shell on a real console... |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="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></h2> |
| <p> |
| |
| You have not paid us a single cent and yet you still have the product of |
| many years of our work. We are not your slaves! We work on BusyBox |
| because we find it useful and interesting. If you go off flaming us, we |
| will ignore you. |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="helpme">I need help with BusyBox! What should I do?</a></h2> |
| <p> |
| |
| If you find that you need help with BusyBox, you can ask for help on the |
| BusyBox mailing list at busybox@mail.busybox.net. In addition to the BusyBox |
| mailing list, Erik (andersee), Manuel (mjn3), Rob (landley) and others are |
| known to hang out on the uClibc IRC channel: #uclibc on irc.freenode.net. |
| (Daily logs of that IRC channel, going back to 2002, are available |
| <a href="http://ibot.Rikers.org/%23uclibc/">here</a>.) |
| |
| <p> |
| |
| <b>Please do not send private email to Rob, Erik, Manuel, or the other |
| BusyBox contributors asking for private help unless you are planning on |
| paying for consulting services.</b> |
| |
| <p> |
| |
| When we answer questions on the BusyBox mailing list, it helps everyone |
| since people with similar problems in the future will be able to get help |
| by searching the mailing list archives. Private help is reserved as a paid |
| service. If you need to use private communication, or if you are serious |
| about getting timely assistance with BusyBox, you should seriously consider |
| paying for consulting services. |
| |
| <p> |
| |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="contracts">I need you to add <favorite feature>! Are the BusyBox |
| developers willing to be paid in order to fix bugs or add in <favorite feature>? |
| Are you willing to provide support contracts?</a></h2> |
| <p> |
| |
| Sure! Now you have our attention! What you should do is contact <a |
| href="mailto:andersen@codepoet.org">Erik Andersen</a> of <a |
| href="http://codepoet-consulting.com/">CodePoet Consulting</a> to bid |
| on your project. If Erik is too busy to personally add your feature, there |
| are many other active BusyBox contributors who will almost certainly be able |
| to help you out. Erik can contact them privately, and may even let you to |
| post your request for services on the mailing list. |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="external">Where can I find other small utilities since busybox |
| does not include the features I want?</a></h2> |
| <p> |
| We maintain such a <a href="tinyutils.html">list</a> on this site! |
| |
| |
| <hr /> |
| <p> |
| <h2><a name="support">I think you guys are great and I want to help support your work!</a></h2> |
| <p> |
| |
| Wow, that would be great! If you would like to make a donation to help |
| support BusyBox, and/or request features, you can click here: |
| |
| <!-- Begin PayPal Logo --> |
| <center> |
| <form action="https://www.paypal.com/cgi-bin/webscr" method="post"> |
| <input type="hidden" name="cmd" value="_xclick"> |
| <input type="hidden" name="business" value="andersen@codepoet.org"> |
| <input type="hidden" name="item_name" value="Support BusyBox"> |
| <input type="hidden" name="image_url" value="http://codepoet-consulting.com/images/codepoet.png"> |
| <input type="hidden" name="no_shipping" value="1"> |
| <input type="image" src="images/donate.png" name="submit" alt="Make donation using PayPal"> |
| </form> |
| </center> |
| <!-- End PayPal Logo --> |
| |
| If you prefer to contact Erik directly to make a donation, donate hardware, |
| request support, etc, you can contact |
| <a href="http://codepoet-consulting.com/">CodePoet Consulting</a> here. |
| CodePoet Consulting can accept both Visa and MasterCard for those that do |
| not trust PayPal... |
| |
| <hr /> |
| <p> |
| <h2><a name="optimize">I want to make busybox even smaller, how do I go about it?</a></h2> |
| <p> |
| To conserve bytes it's good to know where they're being used, and the |
| size of the final executable isn't always a reliable indicator of |
| the size of the components (since various structures are rounded up, |
| so a small change may not even be visible by itself, but many small |
| savings add up). |
| </p> |
| <p> |
| The busybox Makefile can generate a report of how much space is actually |
| being used by each function and variable. Run "<b>make sizes</b>" (preferably |
| with CONFIG_DEBUG off) to get a list of symbols and the amount of |
| space allocated for each one, sorted by size. |
| </p> |
| <hr /> |
| |
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| |
| <br> |
| <br> |
| <br> |
| |
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