Emdebian Crush Quick Start
This is intended to be a quick start guide to Emdebian and (emdebian-tools).
Crush is the cross-built flavour of Emdebian with functional differences to standard Debian. Only ARM packages exist for Crush 1.0 and there are significant problems adding any other architectures.
See the Emdebian website for more on Emdebian Grip - the flavour of Emdebian that is binary-compatible with standard Debian and available for seven architectures, arm, armel, mips, mipsel, powerpc, i386 and amd64.
emdebian-tools (>= 0.9.0) has been split into multiple packages:
emdebian-tools - the build tools. If you expect to make any changes to the current set of packages available for ARM from Emdebian, you will need the build tools. emdebian-tools depends on all the other packages below.
emdebian-rootfs - the installer tools. If you only want to use the current Emdebian packages for ARM without modification to create a root filesystem you can use alongside your kernel and kernel modules, you will only need the installer tools. emdebian-rootfs depends on the keyring and library packages. See EmdebianRootfs for a quick start.
emdebian-archive-keyring - the key for SecureApt support. If you only want to use the current Emdebian toolchains without the Emdebian patches or prebuilt packages, you only need the keyring. You can use the key without using any other Emdebian packages.
This guide concentrates on emdebian-tools - i.e. package building, not installation. See also EmdebianRootfs.
You will need to install a package called emdebian-tools, either from Debian repositories or the Emdebian repository. emdebian-tools also brings in apt-cross and dpkg-cross. subversion is recommended by emdebian-tools and used by emsource later. (emdebian-tools >= 1.0.0 depends on subversion directly.)
$ sudo apt-get install emdebian-tools
If you are installing emdebian-tools within a chroot, you will also need to configure the debconf settings for the emdebian-tools scripts directly.
# unset DEBIAN_FRONTEND # dpkg-reconfigure libemdebian-tools-perl
The configuration will ask you several questions, including where you want to build packages (ensure this directory is writable - the default is only intended for use within a chroot), your username for emdebian svn access if you have one and whether you want to use apt-get or aptitude for toolchain package installation. dpkg-cross will offer you the chance to set a default cross-building architecture which saves a lot of typing later on. If you choose None, you will need to add '--arch ARCH' to all the emdebian-tools commands.
Installing emdebian-tools from Debian makes the updated versions in the Emdebian repository available to apt, so now check for an updated version of the packages, noting that some updates introduce new dependencies:
$ sudo apt-get update $ sudo apt-get dist-upgrade
Always ensure you are running the latest version available of each emdebian-tools package.
After you have the tools, you need to setup an emdebian environment using emsetup. This sets up the ~/.apt-cross dir which contains apt caches and configuration files and adds the Emdebian toolchain repository to your apt sources list. apt will then keep your toolchain updated as normal.
New users are recommended to use at least one -v|--verbose option to all emdebian-tools commands.
emdebian-tools and sudo/su
emsetup, like the rest of emdebian-tools does NOT need to be run as root or under sudo. Tools include code to avoid root as much as possible and the package depends on sudo so that sudo usage can be controlled within the script and used only when absolutely necessary. Using at least one -v|--verbose option will ensure that you will be reminded when emdebian-tools needs to use sudo so that you can enter the sudo passphrase if it is not already cached.
Running emdebian-tools or apt-cross as root or under sudo may complicate the subsequent use of emdebian-tools as a normal user. This includes installing the cross-building toolchain - you should let emsetup do that step rather than running sudo apt-get install yourself.
$ apt-cross --update $ emsetup --verbose --simulate
Check that the output is acceptable, nothing changed yet.
$ emsetup -v
emsetup will install a toolchain for you if a suitable one is available from Emdebian.
If /etc/dpkg-cross/cross-compile isn't fully configured yet, (hint in the manpage), or you have chosen to have no default cross-building architecture, then emsetup requests the use of --arch to determine the target architecture:
$ emsetup -v -s --arch m68k ... $ emsetup -a m68k
Once emsetup is complete, you can use sudo apt-get update; sudo apt-get upgrade to ensure you have the latest versions of apt-cross and emdebian-tools as updates are uploaded to Emdebian between Debian versions.
It is also possible to override the default configuration in /etc/dpkg-cross/cross-compile with ~/.apt-cross/cross-compile.
Package source and Emdebian patches
Now you can run emsource <package> to get a debian package, unpack it and apply / generate any emdebian patches. This is directly equivalent to apt-get source in mainstream debian and then applying some patches. emsource tells you where the package has been unpacked - in an SVN tree beneath your emdebian working directory. (target denotes that these packages are intended for installation directly onto the target embedded device.)
$ emsource -v foo Using foo 0.1.23.4-0.1 Working directory: '/path/to/working/dir' Checking for existing emdebian patches Checking out working copies of existing emdebian patches Checked out revision 1234. Checking for existing build tree in foo-0.1.23.4. Emdebianised source tree for 'foo' exists at '/path/to/working/dir/target/trunk/f/foo/trunk/foo-0.1.23.4' Change to this directory before running 'emdebuild'
Now you can cd into the package directory.
cd /path/to/working/dir/target/trunk/f/foo/trunk/foo-0.1.23.4 gedit debian/rules &
- If you are using Emdebian for ARM, patches are prepared and maintained in Emdebian.
- If you are using ARM but with a customised toolchain or libc environment, you will need to review and possibly modify the Emdebian patches.
If you are using a different architecture, you will need to review the current Emdebian patches and modify values in the architecture-specific cache files - see the Emdebian Developer Guide for detailed information on cache files.
Manual edits of debian/* files
As with any automated packaging process, take a moment to read through amended debian/rules before attempting to do emdebuild to actually build the package. This will you familiarise yourself with the kind of changes that Emdebian makes to Debian packages.
Common additions are noted in the Emdebian Developer Guide but always take care to check for manual rules that install documentation or manpages. You should always check that copyright, changelog and all manpages are removed. If the package uses make install to put such files into debian/ directories, include a line to remove those directories before the debhelper or dpkg commands that build the package:
$(pkgme) $(MAKE) -C . install $(pkgdev) $(MAKE) -C . install-dev $(pkglib) $(MAKE) -C . install-lib $(pkgme) $(MAKE) -C build src-manifest dh_strip dh_compress dh_fixperms dh_makeshlibs -N $(library) dh_makeshlibs -p $(library) -V 'libattr1 (>= 2.4.4-1)' dh_installdeb dh_shlibdeps dh_gencontrol dh_md5sums dh_builddeb
$(pkgme) $(MAKE) -C . install $(pkgdev) $(MAKE) -C . install-dev $(pkglib) $(MAKE) -C . install-lib $(pkgme) $(MAKE) -C build src-manifest $(RM) -r debian/libattr1-dev/usr/share/ $(RM) -r debian/attr/usr/share/ dh_strip dh_compress dh_fixperms dh_makeshlibs -N $(library) dh_makeshlibs -p $(library) -V 'libattr1 (>= 2.4.4-1)' dh_installdeb dh_shlibdeps dh_gencontrol dh_md5sums dh_builddeb
You will need to install any build dependencies as needed with apt-get or aptitude and cross-dependencies with emdebuild --build-dep. emdebuild creates a .build log for you.
$ emdebuild -v
Packages, .changes, .dsc, .diff.gz, patch files and the .build log are created in the directory above:
$ ls /path/to/working/dir/target/trunk/f/foo/trunk/
All questions to the debian-embedded mailing list - emdebian developers are also available on IRC. See the emdebian website for details.
The next stage is the Emdebian Developer Guide.