Buildroot is particularly useful for those engaged in embedded systems development. The processors commonly used in embedded systems are not the x86 processors we are familiar with on personal computers; they may be PowerPC processors, MIPS processors, ARM processors, etc.
Buildroot supports various processors and their variants; it also provides default configurations for several off-the-shelf development boards. Additionally, many third-party projects are based on Buildroot or develop their own BSP or SDK on top of it.
Compilation Environment
Download Path: http://buildroot.org/downloads/
Required Software Dependencies
• Build Tools:– which– sed– make (version 3.81 or any later)– binutils– build-essential (only for Debian based systems)– diffutils– gcc (version 4.8 or any later)– g++ (version 4.8 or any later)– bash– patch– gzip– bzip2– perl (version 5.8.7 or any later)– tar– cpio– unzip– rsync– file (must be in /usr/bin/file)– bc– findutils• Source Acquisition Tools:– wgetOptional Software Dependencies
Recommended Dependency: Python 2.7 or higher
Configuration Interface Dependencies:
1. ncurses5: for using the menuconfig interface.
2. qt5: for using the xconfig interface.
3. glib2, gtk2, and glade2: for using the gconfig interface.
Compilation Process
Compilation Configuration
Run the following command from the Buildroot directory to start different configuration interfaces:
1. Use the original curses-based configurator, which is the traditional text-based configuration interface:
make menuconfig2. Use the new curses-based configurator:
make nconfig3. Use the Qt-based graphical configurator:
make xconfig4. Use the GTK-based graphical configurator:
make gconfigCompilation Command
make -j32Directory Overview
Directory Structure
arch: contains files and configurations related to specific architectures, typically used to support different hardware architectures.
board: contains support files and configurations for specific development boards, usually including settings and patches related to specific hardware.
boot: files and configurations related to bootloaders and startup.
configs: contains predefined configuration files to quickly set up Buildroot to support specific target systems or development boards.
docs: contains documentation and user manuals for Buildroot, providing detailed information on using and configuring Buildroot.
fs: files and configurations related to the filesystem, which may include the construction and configuration of the root filesystem.
linux: contains files and configurations related to the Linux kernel, usually for building and customizing the kernel.
Makefile: the main Makefile that defines the rules and targets for the build process.
Makefile.legacy: possibly a Makefile for older versions or compatibility purposes.
package: contains definitions and configurations for all available software packages, allowing users to select which packages to include in the build.
support: provides support files and tools, possibly including scripts and help documentation.
system: files and settings related to system configuration and management.
utils: contains utility tools and scripts, possibly for various tasks during the build process.
Compilation Output Directory
images: stores all image files (kernel images, bootloaders, and root filesystem images).
build: the build directory for all components (including the tools required by Buildroot on the host and the software packages compiled for the target). This directory contains a subdirectory for each component.
host: contains tools built for the host and the sysroot of the target toolchain. The former is the installation of tools compiled for the host, which are required for Buildroot to function properly, including the cross-compilation toolchain. The latter is a directory resembling the root filesystem hierarchy that contains all the header files and libraries for user-space software packages, which are provided and installed for use by other packages. However, this directory is not intended to be used as the target’s root filesystem, as it contains a large number of development files, unstripped binaries, and libraries, making it too bulky for embedded systems. These development files are used to compile target libraries and applications that depend on other libraries.
staging: a symbolic link to the target toolchain sysroot in host, existing for backward compatibility.
target: contains almost the complete root filesystem for the target: everything needed is here except for the device files in /dev (Buildroot cannot create them as it does not run as root, nor does it want to run as root). Moreover, it does not have the correct permissions (for example, the setuid permission for busybox binaries). Therefore, this directory should not be used on your target. Instead, you should use the images built in the images directory. If you need a tarball image for a root filesystem to boot via NFS, then use the tarball image generated in images and extract it as root. Compared to staging/, target only contains the files and libraries necessary to run the selected target applications: it does not include development files (header files, etc.), and binaries have been stripped.
Actual Environment Compilation Testing
Error opening compilation interface: make menuconfig error, prompting to install ncurses,
Installation command: yum install ncurses-devel
[]# tar xzf buildroot-2024.02.8.tar.gz []# cd buildroot-2024.02.8/[buildroot-2024.02.8]# lsarch boot Config.in configs DEVELOPERS fs Makefile package support toolchainboard CHANGES Config.in.legacy COPYING docs linux Makefile.legacy README system utils[buildroot-2024.02.8]# make menuconfigmkdir -p /root/buildroot-2024.02.8/output/build/buildroot-config/lxdialogPKG_CONFIG_PATH="" make CC="/usr/bin/gcc" HOSTCC="/usr/bin/gcc" \
obj=/root/buildroot-2024.02.8/output/build/buildroot-config -C support/kconfig -f Makefile.br mconfmake[1]: Entering directory '/root/buildroot-2024.02.8/support/kconfig'/usr/bin/gcc -DCURSES_LOC="<curses.h>" -DLOCALE -I/root/buildroot-2024.02.8/output/build/buildroot-config -DCONFIG_="" -MM *.c > /root/buildroot-2024.02.8/output/build/buildroot-config/.depend 2>/dev/null || :/usr/bin/gcc -DCURSES_LOC="<curses.h>" -DLOCALE -I/root/buildroot-2024.02.8/output/build/buildroot-config -DCONFIG_="" -c conf.c -o /root/buildroot-2024.02.8/output/build/buildroot-config/conf.o *** Unable to find the ncurses libraries or the *** required header files. *** 'make menuconfig' requires the ncurses libraries. *** *** Install ncurses (ncurses-devel or libncurses-dev *** depending on your distribution) and try again. *** make[1]: *** [Makefile:253: /root/buildroot-2024.02.8/output/build/buildroot-config/dochecklxdialog] Error 1make[1]: Leaving directory '/root/buildroot-2024.02.8/support/kconfig'make: *** [Makefile:956: /root/buildroot-2024.02.8/output/build/buildroot-config/mconf] Error 2[buildroot-2024.02.8]# yum install ncurses-develError during compilation: make error
Installation: yum install perl-ExtUtils-MakeMaker perl-IPC-Cmd
[buildroot-2024.02.8]# make/usr/bin/make -j1 O=/root/buildroot-2024.02.8/output HOSTCC="/usr/bin/gcc" HOSTCXX="/usr/bin/g++" syncconfigmake[1]: Entering directory '/root/buildroot-2024.02.8'mkdir -p /root/buildroot-2024.02.8/output/build/buildroot-config/lxdialogPKG_CONFIG_PATH="" /usr/bin/make CC="/usr/bin/gcc" HOSTCC="/usr/bin/gcc" \
obj=/root/buildroot-2024.02.8/output/build/buildroot-config -C support/kconfig -f Makefile.br confmake[2]: Entering directory '/root/buildroot-2024.02.8/support/kconfig'/usr/bin/gcc -D_GNU_SOURCE -D_DEFAULT_SOURCE -DCURSES_LOC="<<ncurses.h>" '="" ***="" -dconfig_="" -dlocale="" -dncurses_widechar="1" -i="" -o="" 1<="" [support="" are="" at="" build="" buildroot-2024.02.8="" buildroot-2024.02.8'your="" buildroot-config="" code="" complete="" conf.o="" confmake[2]:="" dependencies="" dependencies.mk:27:="" dependencies]="" directory="" enough;="" error="" extutils::makemaker="" followingmodules="" installation="" ipc::cmdmake:="" is="" kconfig'make[1]:="" least="" leaving="" missing:="" not="" output="" perl="" root="" support="" the="" zconf.tab.o=""></ncurses.h>">Compilation Results
[output]# lsbuild host images staging target[output]# ls images/rootfs.tar[output]# ls target/bin etc lib32 media opt root sbin THIS_IS_NOT_YOUR_ROOT_FILESYSTEM usrdev lib linuxrc mnt proc run sys tmp var[output]# ls build/buildroot-config host-makedevsbuildroot-fs host-mpc-1.2.1build-time.log host-mpfr-4.1.1busybox-1.36.1 host-patchelf-0.13gcc-final-12.4.0 host-skeletonglibc-2.38-81-gc8cb4d2b86ece572793e31a3422ea29e88d77df5 ifupdown-scriptshost-acl-2.3.2 initscriptshost-attr-2.5.2 linux-headers-6.6.58host-autoconf-2.72 locales.nopurgehost-automake-1.16.5 packages-file-list-host.txthost-binutils-2.40 packages-file-list-staging.txthost-bison-3.8.2 packages-file-list.txthost-fakeroot-1.32.1 skeletonhost-gawk-5.3.0 skeleton-init-commonhost-gcc-final-12.4.0 skeleton-init-sysvhost-gcc-initial-12.4.0 toolchainhost-gmp-6.3.0 toolchain-buildroothost-libtool-2.4.6 urandom-scriptshost-m4-1.4.19