Debian package building
This file describes how .deb packages work, how to build them, and how to test them working.
Quick introduction
.deb packages are a way software is packaged for distribution for Debian
and distributions based on Debian (such as Ubuntu, Linux Mint and so on).
The package contains all the files that the package provides, some metainformation about the package (name, version, maintainer, etc.), information about package dependencies (required, optional, conflicts, etc.), the installation and/or removal scripts, as well as some additional information such as changelogs and manual files.
Internally the packages are managed with dpkg,
but end users should be using front-ends such as apt or aptitude.
Required files
To build a package, a number of files is required. Those files are:
debian/controldebian/copyrightdebian/changelogdebian/rules
debian/control
The file that has the metainformation about what packages are built from this source.
The first block of fields contains information about the source of the packages. It contains information, such as the source’s name, section, priority, the required dependencies to build the package, as well as some information about the maintainers and the original author’s pages.
All the subsequent blocks describe each package that is being built by this source. It contains such information as the package’s name and description, architecture, dependencies, other recommended packages.
debian/copyright
This file contains information about the copyright the packages in this source are subject to.
debian/changelog
This file contains information about the changelog of the package.
This file is used for a multitude of purposes, such as determining the version of the package, the distribution and urgency of the package.
debian/rules
The Makefile according to which the package is built.
This file usually includes calls to dh_* commands, which come from the debhelper package.
Building the package
The packages in a given source are built by running the dpkg-buildpackage command,
provided by the dpkg-dev package, in the root folder of the source directory.
The debian directory with the required files must exist in that directory.
The command prepares and compiles the packages, then packages them into .deb package files.
Those files are then placed in the directory above the current working directory.
It is recommended to build the packages on the oldest still compatible version of the OS
to ensure maximum compatibility. This is due to different compiler versions having
different glibc requirements and newer versions of glibc being compatible with
programs built for older versions.
Packages built in Debian will still most likely work on Ubuntu and vice-versa.
Generated files
The files generated by building the packages are:
Debian package files
Debian package files with debug symbols for the binaries
.buildinfofile.changesfile
Debian package files
The build generates a .deb file for each of the packages in the source.
The files are named ${package_name}_${version}_{architecture}.deb.
The package, which is just an archive, contains 3 files:
debian-binary(currently always contains2.0)control.tar.${compression}data.tar.${compression}
control.tar
This archive contains, but is not limited to, these files:
controlmd5sumspreinst(optional)prerm(optional)postinst(optional)preinst(optional)
control
This file contains information about the package itself, such as:
Package name
Package version
Package architecture
Package maintainer
The size of the package when installed
Package dependency information (dependencies, conflicts, etc.)
Description of the package
md5sums
The file contains MD5 checksums for every file in the data.tar archive.
preinst, prerm, postinst, preinst
The scripts to run during the pre-installation (preinst), post-installation (postinst),
pre-removal (prerm) and post-removal (postrm) stages.
data.tar
This archive contains all the files that would end up installed in the system when installing these packages, in the locations that they would end up in, relative to the root directory.
Debian package files with debug symbols for the binaries
The build generates a .ddeb file for each of the packages in the source containing binary files.
The files are named ${package_name}-dbgsym_${version}_{architecture}.ddeb.
The structure of these files is the same as normal .deb files, except that the data.tar file
contains only the debug symbols for the binaries in the non-debug symbol package.
.buildinfo file
The file is named ${source_name}_${version}_{architecture}.buildinfo.
It contains information about the built packages, as well as information about the source.
The information includes:
Name of the source
Packages built
Architecture of the packages
Version of the packages
MD5, SHA1 and SHA256 checksums of the files
Status of the system when the package was built
.changes file
The file is named ${source_name}_${version}_{architecture}.changes.
It contains information about the built packages.
The information includes:
Name of the source
Packages built
Architecture of the packages
Version of the packages
Distribution information of the packages
Maintainer information of the packages
Brief description of the packages
The latest entry in the changelog
MD5, SHA1 and SHA256 checksums of the files
Installing Debian package files
Installing the built .deb packages is done the same way as installing normal packages,
except instead of the package name you give the direct path to the file.
They will function exactly the same as any normal packages installed from repositories.
Example:
apt install ./limesuite_24.0.0-1_amd64.deb ./liblimesuite24.0-1_24.0.0-1_amd64.deb
Testing packages installation
One of the recommended ways to test if the packages are made correctly would be to test them in a Virtual Machine (VM). This allows for incorrectly made packages to not break the main system and to easily restore the system state back to a known good working configuration. This also allows one to mass-test different OS versions without needing to reinstall the OS or use an entirely separate physical computer and/or storage device every time one would want to test a different one.
To test whether the devices themselves function properly with the built packages in a VM requires passing through the devices into the VM. The exact way of doing that differs for each virtualisation platform.
Docker
There exists a Docker file in this repository to generate the .deb packages.
To run the Docker script, use this command:
docker build -o <output_folder> -f DebPackage<version>.Dockerfile .
More information
Some more expanded information from each section:
More reading
Helpful sources for starting out: