# For a description of the syntax of this configuration file,
# see scripts/kbuild/config-language.txt.
mainmenu "BusyBox Configuration"
menu "Busybox Settings"
menu "General Configuration"
prompt "Buffer allocation policy"
There are 3 ways BusyBox can handle buffer allocations:
- Use malloc. This costs code size for the call to xmalloc.
- Put them on stack. For some very small machines with limited stack
space, this can be deadly. For most folks, this works just fine.
- Put them in BSS. This works beautifully for computers with a real
MMU (and OS support), but wastes runtime RAM for uCLinux. This
behavior was the only one available for BusyBox versions 0.48 and
bool "Allocate with Malloc"
bool "Allocate on the Stack"
bool "Allocate in the .bss section"
bool "Show verbose applet usage messages"
All BusyBox applets will show more verbose help messages when
busybox is invoked with --help. This will add a lot of text to the
busybox binary. In the default configuration, this will add about
13k, but it can add much more depending on your configuration.
bool "Support --install [-s] to install applet links at runtime"
Enable 'busybox --install [-s]' support. This will allow you to use
busybox at runtime to create hard links or symlinks for all the
applets that are compiled into busybox. This feature requires the
bool "Enable locale support (system needs locale for this to work)"
Enable this if your system has locale support and you would like
busybox to support locale settings.
bool "Support for devfs"
Enable if you want BusyBox to work with devfs.
bool "Use the devpts filesystem for Unix98 PTYs"
default y if CONFIG_FEATURE_DEVFS
Enable if you want BusyBox to use Unix98 PTY support. If enabled,
busybox will use /dev/ptmx for the master side of the pseudoterminal
and /dev/pts/<number> for the slave side. Otherwise, BSD style
/dev/ttyp<number> will be used. To use this option, you should have
devpts or devfs mounted.
bool "Clean up all memory before exiting (usually not needed)"
As a size optimization, busybox normally exits without explicitly
freeing dynamically allocated memory or closing files. This saves
space since the OS will clean up for us, but it can confuse debuggers
like valgrind, which report tons of memory and resource leaks.
Don't enable this unless you have a really good reason to clean
things up manually.
bool "Support for SUID/SGID handling"
Support SUID and SGID binaries.
bool "Runtime SUID/SGID configuration via /etc/busybox.conf"
default n if CONFIG_FEATURE_SUID
depends on CONFIG_FEATURE_SUID
Allow the SUID / SGID state of an applet to be determined runtime by
checking /etc/busybox.conf. The format of this file is as follows:
<applet> = [Ssx-][Ssx-][x-] (<username>|<uid>).(<groupname>|<gid>)
An example might help:
su = ssx root.0 # applet su can be run by anyone and runs with euid=0/egid=0
su = ssx # exactly the same
mount = sx- root.disk # applet mount can be run by root and members of group disk
# and runs with euid=0
cp = --- # disable applet cp for everyone
The file has to be owned by user root, group root and has to be
writeable only by root:
(chown 0.0 /etc/busybox.conf; chmod 600 /etc/busybox.conf)
The busybox executable has to be owned by user root, group
root and has to be setuid root for this to work:
(chown 0.0 /bin/busybox; chmod 4755 /bin/busybox)
Robert 'sandman' Griebl has more information here:
<url: http://www.softforge.de/bb/suid.html >.
bool "Suppress warning message if /etc/busybox.conf is not readable"
depends on CONFIG_FEATURE_SUID_CONFIG
/etc/busybox.conf should be readable by the user needing the SUID, check
this option to avoid users to be notified about missing permissions.
bool "Support NSA Security Enhanced Linux"
Enable support for SELinux in applets ls, ps, and id. Also provide
the option of compiling in SELinux applets.
If you do not have a complete SELinux userland installed, this stuff
will not compile. Go visit
to download the necessary stuff to allow busybox to compile with
this option enabled. Specifially, libselinux 1.28 or better is
directly required by busybox. If the installation is located in a
non-standard directory, provide it by invoking make as follows:
Most people will leave this set to 'N'.
menu 'Build Options'
bool "Build BusyBox as a static binary (no shared libs)"
If you want to build a static BusyBox binary, which does not
use or require any shared libraries, then enable this option.
This can cause BusyBox to be considerably larger, so you should
leave this option false unless you have a good reason (i.e.
your target platform does not support shared libraries, or
you are building an initrd which doesn't need anything but
Most people will leave this set to 'N'.
# The busybox shared library feature is there so make standalone can produce
# smaller applets. Since make standalone isn't in yet, there's nothing using
# this yet, and so it's disabled.
bool "Build shared libbusybox"
depends on CONFIG_DISABLE_SHARED
Build a shared library libbusybox.so which contains all
libraries used inside busybox.
bool "Feature-complete libbusybox"
default n if !CONFIG_FEATURE_SHARED_BUSYBOX
depends on CONFIG_BUILD_LIBBUSYBOX
Build a libbusybox with the complete feature-set, disregarding
the actually selected config.
Normally, libbusybox will only contain the features which are
used by busybox itself. If you plan to write a separate
standalone application which uses libbusybox say 'Y'.
Note: libbusybox is GPL, not LGPL, and exports no stable API that
might act as a copyright barrier. We can and will modify the
exported function set between releases (even minor version number
changes), and happily break out-of-tree features.
Say 'N' if in doubt.
bool "Use shared libbusybox for busybox"
default y if CONFIG_BUILD_LIBBUSYBOX
depends on !CONFIG_STATIC && CONFIG_BUILD_LIBBUSYBOX
Use libbusybox.so also for busybox itself.
You need to have a working dynamic linker to use this variant.
bool "Build with Large File Support (for accessing files > 2 GB)"
If you want to build BusyBox with large file support, then enable
this option. This will have no effect if your kernel or your C
library lacks large file support for large files. Some of the
programs that can benefit from large file support include dd, gzip,
cp, mount, tar, and many others. If you want to access files larger
than 2 Gigabytes, enable this option. Otherwise, leave it set to 'N'.
bool "Do you want to build BusyBox with a Cross Compiler?"
Do you want to build BusyBox with a Cross Compiler? If so,
then enable this option. Otherwise leave it set to 'N'.
string "Cross Compiler prefix"
depends on USING_CROSS_COMPILER
If you want to build BusyBox with a cross compiler, then you
will need to set this to the cross-compiler prefix. For example,
if my cross-compiler is /usr/i386-linux-uclibc/bin/i386-uclibc-gcc
then I would enter '/usr/i386-linux-uclibc/bin/i386-uclibc-' here,
which will ensure the correct compiler is used.
string "Any extra CFLAGS options for the compiler?"
Do you want to pass any extra CFLAGS options to the compiler as
you build BusyBox? If so, this is the option for you... For example,
if you want to add some simple compiler switches (like -march=i686),
or check for warnings using -Werror, just those options here.
bool "Compile all sources at once"
Normally each source-file is compiled with one invocation of
If you set this option, all sources are compiled at once.
This gives the compiler more opportunities to optimize which can
result in smaller and/or faster binaries.
Setting this option will consume alot of memory, e.g. if you
enable all applets with all features, gcc uses more than 300MB
RAM during compilation of busybox.
This option is most likely only beneficial for newer compilers
such as gcc-4.1 and above.
Say 'N' unless you know what you are doing.
menu 'Debugging Options'
bool "Build BusyBox with Debugging symbols"
Say Y here if you wish to compile BusyBox with debugging symbols.
This will allow you to use a debugger to examine BusyBox internals
while applets are running. This increases the size of the binary
considerably and should only be used when doing development.
If you are doing development and want to debug BusyBox, answer Y.
Most people should answer N.
prompt "Additional debugging library"
depends on CONFIG_DEBUG
Using an additional debugging library will make BusyBox become
considerable larger and will cause it to run more slowly. You
should always leave this option disabled for production use.
This enables compiling with dmalloc ( http://dmalloc.com/ )
which is an excellent public domain mem leak and malloc problem
detector. To enable dmalloc, before running busybox you will
want to properly set your environment, for example:
The 'debug=' value is generated using the following command
dmalloc -p log-stats -p log-non-free -p log-bad-space -p log-elapsed-time \
-p check-fence -p check-heap -p check-lists -p check-blank \
-p check-funcs -p realloc-copy -p allow-free-null
This enables compiling with Electric-fence support. Electric
fence is another very useful malloc debugging library which uses
your computer's virtual memory hardware to detect illegal memory
accesses. This support will make BusyBox be considerable larger
and run slower, so you should leave this option disabled unless
you are hunting a hard to find memory problem.
bool "Disable obsolete features removed before SUSv3?"
This option will disable backwards compatability with SuSv2,
specifically, old-style numeric options ('command -1 <file>')
will not be supported in head, tail, and fold. (Note: should
yank from renice too.)
menu 'Installation Options'
bool "Don't use /usr"
Disable use of /usr. Don't activate this option if you don't know
that you really want this behaviour.
prompt "Applets links"
Choose how you install applets links.
bool "as soft-links"
Install applets as soft-links to the busybox binary. This needs some
free inodes on the filesystem, but might help with filesystem
generators that can't cope with hard-links.
bool "as hard-links"
Install applets as hard-links to the busybox binary. This might count
on a filesystem with few inodes.
prompt "not installed"
depends on CONFIG_FEATURE_INSTALLER || CONFIG_FEATURE_SH_STANDALONE_SHELL
Do not install applets links. Usefull when using the -install feature
or a standalone shell for rescue pruposes.
string "BusyBox installation prefix"
Define your directory to install BusyBox files/subdirs in.