mirror of
https://github.com/topjohnwu/ndk-busybox.git
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c77a58fb2d
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
205 lines
8.5 KiB
Plaintext
205 lines
8.5 KiB
Plaintext
Please see the LICENSE file for details on copying and usage.
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Please refer to the INSTALL file for instructions on how to build.
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What is busybox:
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BusyBox combines tiny versions of many common UNIX utilities into a single
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small executable. It provides minimalist replacements for most of the
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utilities you usually find in bzip2, coreutils, dhcp, diffutils, e2fsprogs,
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file, findutils, gawk, grep, inetutils, less, modutils, net-tools, procps,
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sed, shadow, sysklogd, sysvinit, tar, util-linux, and vim. The utilities
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in BusyBox often have fewer options than their full-featured cousins;
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however, the options that are included provide the expected functionality
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and behave very much like their larger counterparts.
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BusyBox has been written with size-optimization and limited resources in
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mind, both to produce small binaries and to reduce run-time memory usage.
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Busybox is also extremely modular so you can easily include or exclude
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commands (or features) at compile time. This makes it easy to customize
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embedded systems; to create a working system, just add /dev, /etc, and a
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Linux kernel. Busybox (usually together with uClibc) has also been used as
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a component of "thin client" desktop systems, live-CD distributions, rescue
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disks, installers, and so on.
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BusyBox provides a fairly complete POSIX environment for any small system,
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both embedded environments and more full featured systems concerned about
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space. Busybox is slowly working towards implementing the full Single Unix
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Specification V3 (http://www.opengroup.org/onlinepubs/009695399/), but isn't
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there yet (and for size reasons will probably support at most UTF-8 for
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internationalization). We are also interested in passing the Linux Test
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Project (http://ltp.sourceforge.net).
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----------------
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Using busybox:
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BusyBox is extremely configurable. This allows you to include only the
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components and options you need, thereby reducing binary size. Run 'make
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config' or 'make menuconfig' to select the functionality that you wish to
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enable. (See 'make help' for more commands.)
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The behavior of busybox is determined by the name it's called under: as
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"cp" it behaves like cp, as "sed" it behaves like sed, and so on. Called
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as "busybox" it takes the second argument as the name of the applet to
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run (I.E. "./busybox ls -l /proc").
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The "standalone shell" mode is an easy way to try out busybox; this is a
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command shell that calls the built-in applets without needing them to be
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installed in the path. (Note that this requires /proc to be mounted, if
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testing from a boot floppy or in a chroot environment.)
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The build automatically generates a file "busybox.links", which is used by
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'make install' to create symlinks to the BusyBox binary for all compiled in
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commands. This uses the CONFIG_PREFIX environment variable to specify
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where to install, and installs hardlinks or symlinks depending
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on the configuration preferences. (You can also manually run
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the install script at "applets/install.sh").
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----------------
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Downloading the current source code:
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Source for the latest released version, as well as daily snapshots, can always
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be downloaded from
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http://busybox.net/downloads/
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You can browse the up to the minute source code and change history online.
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http://git.busybox.net/busybox/
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Anonymous GIT access is available. For instructions, check out:
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http://www.busybox.net/source.html
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For those that are actively contributing and would like to check files in,
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see:
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http://busybox.net/developer.html
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The developers also have a bug and patch tracking system
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(https://bugs.busybox.net) although posting a bug/patch to the mailing list
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is generally a faster way of getting it fixed, and the complete archive of
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what happened is the git changelog.
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Note: if you want to compile busybox in a busybox environment you must
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select CONFIG_DESKTOP.
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----------------
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Getting help:
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when you find you need help, you can check out the busybox mailing list
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archives at http://busybox.net/lists/busybox/ or even join
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the mailing list if you are interested.
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----------------
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Bugs:
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if you find bugs, please submit a detailed bug report to the busybox mailing
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list at busybox@busybox.net. a well-written bug report should include a
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transcript of a shell session that demonstrates the bad behavior and enables
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anyone else to duplicate the bug on their own machine. the following is such
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an example:
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to: busybox@busybox.net
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from: diligent@testing.linux.org
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subject: /bin/date doesn't work
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package: busybox
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version: 1.00
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when i execute busybox 'date' it produces unexpected results.
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with gnu date i get the following output:
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$ date
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fri oct 8 14:19:41 mdt 2004
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but when i use busybox date i get this instead:
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$ date
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illegal instruction
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i am using debian unstable, kernel version 2.4.25-vrs2 on a netwinder,
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and the latest uclibc from cvs.
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-diligent
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note the careful description and use of examples showing not only what
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busybox does, but also a counter example showing what an equivalent app
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does (or pointing to the text of a relevant standard). Bug reports lacking
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such detail may never be fixed... Thanks for understanding.
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----------------
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Portability:
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Busybox is developed and tested on Linux 2.4 and 2.6 kernels, compiled
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with gcc (the unit-at-a-time optimizations in version 3.4 and later are
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worth upgrading to get, but older versions should work), and linked against
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uClibc (0.9.27 or greater) or glibc (2.2 or greater). In such an
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environment, the full set of busybox features should work, and if
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anything doesn't we want to know about it so we can fix it.
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There are many other environments out there, in which busybox may build
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and run just fine. We just don't test them. Since busybox consists of a
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large number of more or less independent applets, portability is a question
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of which features work where. Some busybox applets (such as cat and rm) are
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highly portable and likely to work just about anywhere, while others (such as
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insmod and losetup) require recent Linux kernels with recent C libraries.
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Earlier versions of Linux and glibc may or may not work, for any given
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configuration. Linux 2.2 or earlier should mostly work (there's still
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some support code in things like mount.c) but this is no longer regularly
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tested, and inherently won't support certain features (such as long files
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and --bind mounts). The same is true for glibc 2.0 and 2.1: expect a higher
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testing and debugging burden using such old infrastructure. (The busybox
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developers are not very interested in supporting these older versions, but
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will probably accept small self-contained patches to fix simple problems.)
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Some environments are not recommended. Early versions of uClibc were buggy
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and missing many features: upgrade. Linking against libc5 or dietlibc is
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not supported and not interesting to the busybox developers. (The first is
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obsolete and has no known size or feature advantages over uClibc, the second
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has known bugs that its developers have actively refused to fix.) Ancient
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Linux kernels (2.0.x and earlier) are similarly uninteresting.
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In theory it's possible to use Busybox under other operating systems (such as
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MacOS X, Solaris, Cygwin, or the BSD Fork Du Jour). This generally involves
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a different kernel and a different C library at the same time. While it
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should be possible to port the majority of the code to work in one of
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these environments, don't be surprised if it doesn't work out of the box. If
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you're into that sort of thing, start small (selecting just a few applets)
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and work your way up.
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In 2005 Shaun Jackman has ported busybox to a combination of newlib
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and libgloss, and some of his patches have been integrated.
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Supported hardware:
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BusyBox in general will build on any architecture supported by gcc. We
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support both 32 and 64 bit platforms, and both big and little endian
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systems.
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Under 2.4 Linux kernels, kernel module loading was implemented in a
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platform-specific manner. Busybox's insmod utility has been reported to
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work under ARM, CRIS, H8/300, x86, ia64, x86_64, m68k, MIPS, PowerPC, S390,
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SH3/4/5, Sparc, and v850e. Anything else probably won't work.
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The module loading mechanism for the 2.6 kernel is much more generic, and
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we believe 2.6.x kernel module loading support should work on all
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architectures supported by the kernel.
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----------------
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Please feed suggestions, bug reports, insults, and bribes back to the busybox
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mailing list:
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busybox@busybox.net
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and/or maintainer:
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Denys Vlasenko
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<vda.linux@googlemail.com>
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