3. Source packages (from old Packaging Manual)¶
The Debian binary packages in the distribution are generated from Debian sources, which are in a special format to assist the easy and automatic building of binaries.
3.1. Tools for processing source packages¶
Various tools are provided for manipulating source packages; they pack and unpack sources and help build of binary packages and help manage the distribution of new versions.
They are introduced and typical uses described here; see dpkg-source1 for full documentation about their arguments and operation.
For examples of how to construct a Debian source package, and how to use
those utilities that are used by Debian source packages, please see the
hello example package.
dpkg-source - packs and unpacks Debian source packages¶
This program is frequently used by hand, and is also called from
package-independent automated building scripts such as
To unpack a package it is typically invoked with
dpkg-source -x .../path/to/filename.dsc
filename.diff.gz (if applicable) in
the same directory. It unpacks into
package-version, and if
package-version.orig, in the current directory.
To create a packed source archive it is typically invoked:
dpkg-source -b package-version
This will create the
appropriate) in the current directory.
dpkg-source does not clean
the source tree first - this must be done separately if it is required.
See also Section 3.3: Source packages as archives.
dpkg-buildpackage - overall package-building control script¶
dpkg-gencontrol - generates binary package control files¶
This program is usually called from
Section 3.2: The Debian package source tree) in the top level of the source
This is usually done just before the files and directories in the
temporary directory tree where the package is being built have their
permissions and ownerships set and the package is constructed using
dpkg-gencontrol must be called after all the files which are to go
into the package have been placed in the temporary build directory, so
that its calculation of the installed size of a package is correct.
It is also necessary for
dpkg-gencontrol to be run after
dpkg-shlibdeps so that the variable substitutions created by
debian/substvars are available.
For a package which generates only one binary package, and which builds
debian/tmp relative to the top of the source package, it is
usually sufficient to call
Sources which build several binaries will typically need something like:
dpkg-gencontrol -Pdebian/pkg -ppackage
dpkg-gencontrol that the package is being built in
a non-default directory, and the
-p tells it which package’s control
file should be generated.
dpkg-gencontrol also adds information to the list of files in
debian/files, for the benefit of (for example) a future invocation
dpkg-distaddfile - adds a file to
Some packages’ uploads need to include files other than the source and binary package files.
dpkg-distaddfile adds a file to the
debian/files file so that it
will be included in the
.changes file when
It is usually invoked from the
binary target of
dpkg-distaddfile filename section priority
The filename is relative to the directory where
expect to find it - this is usually the directory above the top level of
the source tree. The
debian/rules target should put the file there
just before or just after calling
The section and priority are passed unchanged into the resulting
dpkg-genchanges - generates a
.changes upload control file¶
dpkg-parsechangelog - produces parsed representation of a changelog¶
dpkg-architecture - information about the build and host system¶
3.2. The Debian package source tree¶
The source archive scheme described later is intended to allow a Debian package source tree with some associated control information to be reproduced and transported easily. The Debian package source tree is a version of the original program with certain files added for the benefit of the packaging process, and with any other changes required made to the rest of the source code and installation scripts.
The extra files created for Debian are in the subdirectory
the top level of the Debian package source tree. They are described
debian/rules - the main building script¶
debian/substvars and variable substitutions¶
This is the default temporary location for the construction of binary
packages by the
binary target. The directory
tmp serves as the
root of the file system tree as it is being constructed (for example, by
using the package’s upstream makefiles install targets and redirecting
the output there), and it also contains the
DEBIAN subdirectory. See
Section 2.1: Creating package files - dpkg-deb.
This is only a default and can be easily overridden. Most packaging
tools no longer use
debian/tmp, instead preferring
for the common case of a source package building only one binary
package. Such tools usually only use
debian/tmp as a temporary
staging area for built files and do not construct packages from it.
If several binary packages are generated from the same source tree, it
is usual to use a separate
debian/pkg directory for each binary
package as the temporary construction locations.
Whatever temporary directories are created and used by the
target must of course be removed by the
3.3. Source packages as archives¶
As it exists on the FTP site, a Debian source package consists of three related files. You must have the right versions of all three to be able to use them.
- Debian source control file -
- This file is a control file used by
dpkg-sourceto extract a source package. See Section 5.4: Debian source control files – .dsc.
- Original source archive -
- This is a compressed (with
tarfile containing the source code from the upstream authors of the program.
- Debian package diff -
This is a unified context diff (
diff -u) giving the changes which are required to turn the original source into the Debian source. These changes may only include editing and creating plain files. The permissions of files, the targets of symbolic links and the characteristics of special files or pipes may not be changed and no files may be removed or renamed.
All the directories in the diff must exist, except the
debiansubdirectory of the top of the source tree, which will be created by
dpkg-sourceif necessary when unpacking.
dpkg-sourceprogram will automatically make the
debian/rulesfile executable (see below).
If there is no original source code - for example, if the package is
specially prepared for Debian or the Debian maintainer is the same as
the upstream maintainer - the format is slightly different: then there
is no diff, and the tarfile is named
preferably contains a directory named
3.4. Unpacking a Debian source package without
dpkg-source -x is the recommended way to unpack a Debian source
package. However, if it is not available it is possible to unpack a
Debian source archive as follows:
- Untar the tarfile, which will create a
- Rename the
- Create the subdirectory
debianat the top of the source tree.
- Apply the diff using
- Untar the tarfile again if you want a copy of the original source code alongside the Debian version.
It is not possible to generate a valid Debian source archive without
dpkg-source. In particular, attempting to use
directly to generate the
.diff.gz file will not work.
3.4.1. Restrictions on objects in source packages¶
The source packaging tools manage the changes between the original and
Debian source using
patch. Turning the original source
tree as included in the
.orig.tar.gz into the Debian package source
must not involve any changes which cannot be handled by these tools.
Problematic changes which cause
dpkg-source to halt with an error
when building the source package are:
- Adding or removing symbolic links, sockets or pipes.
- Changing the targets of symbolic links.
- Creating directories, other than
- Changes to the contents of binary files.
Changes which cause
dpkg-source to print a warning but continue
- Removing files, directories or symlinks. 
- Changed text files which are missing the usual final newline (either in the original or the modified source tree).
Changes which are not represented, but which are not detected by
- Changing the permissions of files (other than
debian/rules) and directories.
debian directory and
debian/rules are handled specially by
dpkg-source - before applying the changes it will create the
debian directory, and afterwards it will make
|||This is so that the control file which is produced has the right permissions|
|||This is not currently detected when building source packages, but only when extracting them.|
|||Hard links may be permitted at some point in the future, but would require a fair amount of work.|
|||Setgid directories are allowed.|
|||Renaming a file is not treated specially - it is seen as the removal of the old file (which generates a warning, but is otherwise ignored), and the creation of the new one.|