<abstract>
This manual describes the policy requirements for the Debian
- GNU/Linux distribution. This includes the structure and
+ distribution. This includes the structure and
contents of the Debian archive and several design issues of
the operating system, as well as technical requirements that
each package must satisfy to be included in the distribution.
<p>
A copy of the GNU General Public License is available as
- <file>/usr/share/common-licenses/GPL</file> in the Debian GNU/Linux
+ <file>/usr/share/common-licenses/GPL</file> in the Debian
distribution or on the World Wide Web at
<url id="http://www.gnu.org/copyleft/gpl.html"
name="the GNU General Public Licence">. You can also
<heading>Scope</heading>
<p>
This manual describes the policy requirements for the Debian
- GNU/Linux distribution. This includes the structure and
+ distribution. This includes the structure and
contents of the Debian archive and several design issues of the
operating system, as well as technical requirements that
each package must satisfy to be included in the
<heading>The Debian Archive</heading>
<p>
- The Debian GNU/Linux system is maintained and distributed as a
+ The Debian system is maintained and distributed as a
collection of <em>packages</em>. Since there are so many of
them (currently well over 15000), they are split into
<em>sections</em> and given <em>priorities</em> to simplify
</p>
<p>
- The <em>main</em> archive area forms the <em>Debian GNU/Linux
- distribution</em>.
+ The <em>main</em> archive area forms the <em>Debian distribution</em>.
</p>
<p>
<heading>Binary packages</heading>
<p>
- The Debian GNU/Linux distribution is based on the Debian
+ The Debian distribution is based on the Debian
package management system, called <prgn>dpkg</prgn>. Thus,
all packages in the Debian distribution must be provided
in the <tt>.deb</tt> file format.
</p>
+ <p>
+ A <tt>.deb</tt> package contains two sets of files: a set of files
+ to install on the system when the package is installed, and a set
+ of files that provide additional metadata about the package or
+ which are executed when the package is installed or removed. This
+ second set of files is called <em>control information files</em>.
+ Among those files are the package maintainer scripts
+ and <file>control</file>, the <qref id="binarycontrolfiles">binary
+ package control file</qref> that contains the control fields for
+ the package. Other control information files
+ include <qref id="sharedlibs-shlibdeps">the <file>shlibs</file>
+ file</qref> used to store shared library dependency information
+ and the <file>conffiles</file> file that lists the package's
+ configuration files (described in <ref id="config-files">).
+ </p>
+
+ <p>
+ There is unfortunately a collision of terminology here between
+ control information files and files in the Debian control file
+ format. Throughout this document, a <em>control file</em> refers
+ to a file in the Debian control file format. These files are
+ documented in <ref id="controlfields">. Only files referred to
+ specifically as <em>control information files</em> are the files
+ included in the control information file member of
+ the <file>.deb</file> file format used by binary packages. Most
+ control information files are not in the Debian control file
+ format.
+ </p>
+
<sect>
<heading>The package name</heading>
<p>
In general, Debian packages should use the same version
- numbers as the upstream sources.
- </p>
-
- <p>
- However, in some cases where the upstream version number is
- based on a date (e.g., a development "snapshot" release) the
- package management system cannot handle these version
- numbers without epochs. For example, dpkg will consider
- "96May01" to be greater than "96Dec24".
+ numbers as the upstream sources. However, upstream version
+ numbers based on some date formats (sometimes used for
+ development or "snapshot" releases) will not be ordered
+ correctly by the package management software. For
+ example, <prgn>dpkg</prgn> will consider "96May01" to be
+ greater than "96Dec24".
</p>
<p>
To prevent having to use epochs for every new upstream
- version, the date based portion of the version number
- should be changed to the following format in such cases:
- "19960501", "19961224". It is up to the maintainer whether
- they want to bother the upstream maintainer to change
- the version numbers upstream, too.
+ version, the date-based portion of any upstream version number
+ should be given in a way that sorts correctly: four-digit year
+ first, followed by a two-digit numeric month, followed by a
+ two-digit numeric date, possibly with punctuation between the
+ components.
</p>
<p>
- Note that other version formats based on dates which are
- parsed correctly by the package management system should
- <em>not</em> be changed.
- </p>
-
- <p>
- Native Debian packages (i.e., packages which have been
- written especially for Debian) whose version numbers include
- dates should always use the "YYYYMMDD" format.
+ Native Debian packages (i.e., packages which have been written
+ especially for Debian) whose version numbers include dates
+ should also follow these rules. If punctuation is desired
+ between the date components, remember that hyphen (<tt>-</tt>)
+ cannot be used in native package versions. Period
+ (<tt>.</tt>) is normally a good choice.
</p>
</sect1>
</sect>
- <sect>
+ <sect id="maintainer">
<heading>The maintainer of a package</heading>
<p>
- Every package must have a Debian maintainer (the
- maintainer may be one person or a group of people
- reachable from a common email address, such as a mailing
- list). The maintainer is responsible for ensuring that
- the package is placed in the appropriate distributions.
- </p>
-
- <p>
- The maintainer must be specified in the
- <tt>Maintainer</tt> control field with their correct name
- and a working email address. If one person maintains
- several packages, they should try to avoid having
- different forms of their name and email address in
+ Every package must have a maintainer, except for orphaned
+ packages as described below. The maintainer may be one person
+ or a group of people reachable from a common email address, such
+ as a mailing list. The maintainer is responsible for
+ maintaining the Debian packaging files, evaluating and
+ responding appropriately to reported bugs, uploading new
+ versions of the package (either directly or through a sponsor),
+ ensuring that the package is placed in the appropriate archive
+ area and included in Debian releases as appropriate for the
+ stability and utility of the package, and requesting removal of
+ the package from the Debian distribution if it is no longer
+ useful or maintainable.
+ </p>
+
+ <p>
+ The maintainer must be specified in the <tt>Maintainer</tt>
+ control field with their correct name and a working email
+ address. The email address given in the <tt>Maintainer</tt>
+ control field must accept mail from those role accounts in
+ Debian used to send automated mails regarding the package. This
+ includes non-spam mail from the bug-tracking system, all mail
+ from the Debian archive maintenance software, and other role
+ accounts or automated processes that are commonly agreed on by
+ the project.<footnote>
+ A sample implementation of such a whitelist written for the
+ Mailman mailing list management software is used for mailing
+ lists hosted by alioth.debian.org.
+ </footnote>
+ If one person or team maintains several packages, they should
+ use the same form of their name and email address in
the <tt>Maintainer</tt> fields of those packages.
</p>
</p>
<p>
- If the maintainer of a package quits from the Debian
- project, "Debian QA Group"
- <email>packages@qa.debian.org</email> takes over the
- maintainer-ship of the package until someone else
- volunteers for that task. These packages are called
- <em>orphaned packages</em>.<footnote>
- The detailed procedure for doing this gracefully can
- be found in the Debian Developer's Reference,
- see <ref id="related">.
+ If the maintainer of the package is a team of people with a
+ shared email address, the <tt>Uploaders</tt> control field must
+ be present and must contain at least one human with their
+ personal email address. See <ref id="f-Uploaders"> for the
+ syntax of that field.
+ </p>
+
+ <p>
+ An orphaned package is one with no current maintainer. Orphaned
+ packages should have their <tt>Maintainer</tt> control field set
+ to <tt>Debian QA Group <packages@qa.debian.org></tt>.
+ These packages are considered maintained by the Debian project
+ as a whole until someone else volunteers to take over
+ maintenance.<footnote>
+ The detailed procedure for gracefully orphaning a package can
+ be found in the Debian Developer's Reference
+ (see <ref id="related">).
</footnote>
</p>
</sect>
<heading>The description of a package</heading>
<p>
- Every Debian package must have an extended description
- stored in the appropriate field of the control record.
- The technical information about the format of the
+ Every Debian package must have a <tt>Description</tt> control
+ field which contains a synopsis and extended description of the
+ package. Technical information about the format of the
<tt>Description</tt> field is in <ref id="f-Description">.
</p>
<p>
The <tt>base system</tt> is a minimum subset of the Debian
- GNU/Linux system that is installed before everything else
+ system that is installed before everything else
on a new system. Only very few packages are allowed to form
part of the base system, in order to keep the required disk
usage very small.
must be available and usable on the system at all times, even
when packages are in an unconfigured (but unpacked) state.
Packages are tagged <tt>essential</tt> for a system using the
- <tt>Essential</tt> control file field. The format of the
+ <tt>Essential</tt> control field. The format of the
<tt>Essential</tt> control field is described in <ref
id="f-Essential">.
</p>
<p>
Packages which use the Debian Configuration Management
- Specification may contain an additional
- <prgn>config</prgn> script and a <tt>templates</tt>
- file in their control archive<footnote>
- The control.tar.gz inside the .deb.
- See <manref name="deb" section="5">.
- </footnote>.
- The <prgn>config</prgn> script might be run before the
- <prgn>preinst</prgn> script, and before the package is unpacked
- or any of its dependencies or pre-dependencies are satisfied.
- Therefore it must work using only the tools present in
- <em>essential</em> packages.<footnote>
+ Specification may contain the additional control information
+ files <file>config</file>
+ and <file>templates</file>. <file>config</file> is an
+ additional maintainer script used for package configuration,
+ and <file>templates</file> contains templates used for user
+ prompting. The <prgn>config</prgn> script might be run before
+ the <prgn>preinst</prgn> script and before the package is
+ unpacked or any of its dependencies or pre-dependencies are
+ satisfied. Therefore it must work using only the tools
+ present in <em>essential</em> packages.<footnote>
<package>Debconf</package> or another tool that
implements the Debian Configuration Management
Specification will also be installed, and any
The maintainer name and email address used in the changelog
should be the details of the person uploading <em>this</em>
version. They are <em>not</em> necessarily those of the
- usual package maintainer. The information here will be
- copied to the <tt>Changed-By</tt> field in the
- <tt>.changes</tt> file (see <ref id="f-Changed-By">),
- and then later used to send an acknowledgement when the
- upload has been installed.
+ usual package maintainer.<footnote>
+ If the developer uploading the package is not one of the usual
+ maintainers of the package (as listed in
+ the <qref id="f-Maintainer"><tt>Maintainer</tt></qref>
+ or <qref id="f-Uploaders"><tt>Uploaders</tt></qref> control
+ fields of the package), the first line of the changelog is
+ conventionally used to explain why a non-maintainer is
+ uploading the package. The Debian Developer's Reference
+ (see <ref id="related">) documents the conventions
+ used.</footnote>
+ The information here will be copied to the <tt>Changed-By</tt>
+ field in the <tt>.changes</tt> file
+ (see <ref id="f-Changed-By">), and then later used to send an
+ acknowledgement when the upload has been installed.
</p>
<p>
identical behavior.
</p>
+ <p>
+ The following targets are required and must be implemented
+ by <file>debian/rules</file>: <tt>clean</tt>, <tt>binary</tt>,
+ <tt>binary-arch</tt>, <tt>binary-indep</tt>, and <tt>build</tt>.
+ These are the targets called by <prgn>dpkg-buildpackage</prgn>.
+ </p>
+
<p>
Since an interactive <file>debian/rules</file> script makes it
- impossible to auto-compile that package and also makes it
- hard for other people to reproduce the same binary
- package, all <em>required targets</em> must be
- non-interactive. At a minimum, required targets are the
- ones called by <prgn>dpkg-buildpackage</prgn>, namely,
- <em>clean</em>, <em>binary</em>, <em>binary-arch</em>,
- <em>binary-indep</em>, and <em>build</em>. It also follows
- that any target that these targets depend on must also be
+ impossible to auto-compile that package and also makes it hard
+ for other people to reproduce the same binary package, all
+ required targets must be non-interactive. It also follows that
+ any target that these targets depend on must also be
non-interactive.
</p>
<p>
- The targets are as follows (required unless stated otherwise):
+ The targets are as follows:
<taglist>
- <tag><tt>build</tt></tag>
+ <tag><tt>build</tt> (required)</tag>
<item>
<p>
The <tt>build</tt> target should perform all the
</p>
</item>
- <tag><tt>binary</tt>, <tt>binary-arch</tt>,
- <tt>binary-indep</tt>
+ <tag><tt>binary</tt> (required), <tt>binary-arch</tt>
+ (required), <tt>binary-indep</tt> (required)
</tag>
<item>
<p>
</p>
</item>
- <tag><tt>clean</tt></tag>
+ <tag><tt>clean</tt> (required)</tag>
<item>
<p>
This must undo any effects that the <tt>build</tt>
<p>
The architectures we build on and build for are determined
- by <prgn>make</prgn> variables using the utility
- <qref id="pkg-dpkg-architecture"><prgn>dpkg-architecture</prgn></qref>.
- You can determine the
- Debian architecture and the GNU style architecture
- specification string for the build machine (the machine type
- we are building on) as well as for the host machine (the
- machine type we are building for). Here is a list of
- supported <prgn>make</prgn> variables:
+ by <prgn>make</prgn> variables using the
+ utility <qref id="pkg-dpkg-architecture"><prgn>dpkg-architecture</prgn></qref>.
+ You can determine the Debian architecture and the GNU style
+ architecture specification string for the build architecture as
+ well as for the host architecture. The build architecture is
+ the architecture on which <file>debian/rules</file> is run and
+ the package build is performed. The host architecture is the
+ architecture on which the resulting package will be installed
+ and run. These are normally the same, but may be different in
+ the case of cross-compilation (building packages for one
+ architecture on machines of a different architecture).
+ </p>
+
+ <p>
+ Here is a list of supported <prgn>make</prgn> variables:
<list compact="compact">
<item>
<tt>DEB_*_ARCH</tt> (the Debian architecture)
<tt>DEB_*_GNU_TYPE</tt>)
</list>
where <tt>*</tt> is either <tt>BUILD</tt> for specification of
- the build machine or <tt>HOST</tt> for specification of the
- host machine.
+ the build architecture or <tt>HOST</tt> for specification of the
+ host architecture.
</p>
<p>
<heading>Variable substitutions: <file>debian/substvars</file></heading>
<p>
- When <prgn>dpkg-gencontrol</prgn>,
- <prgn>dpkg-genchanges</prgn> and <prgn>dpkg-source</prgn>
- generate control files they perform variable substitutions
- on their output just before writing it. Variable
+ When <prgn>dpkg-gencontrol</prgn>
+ generates <qref id="binarycontrolfiles">binary package control
+ files</qref> (<file>DEBIAN/control</file>), it performs variable
+ substitutions on its output just before writing it. Variable
substitutions have the form <tt>${<var>variable</var>}</tt>.
The optional file <file>debian/substvars</file> contains
variable substitutions to be used; variables can also be set
directly from <file>debian/rules</file> using the <tt>-V</tt>
- option to the source packaging commands, and certain
- predefined variables are also available.
+ option to the source packaging commands, and certain predefined
+ variables are also available.
</p>
<p>
<heading>Optional upstream source location: <file>debian/watch</file></heading>
<p>
- This is an optional, recommended control file for the
- <tt>uscan</tt> utility which defines how to automatically
- scan ftp or http sites for newly available updates of the
- package. This is used by <url id="
- http://dehs.alioth.debian.org/"> and other Debian QA tools
- to help with quality control and maintenance of the
+ This is an optional, recommended configuration file for the
+ <tt>uscan</tt> utility which defines how to automatically scan
+ ftp or http sites for newly available updates of the
+ package. This is used
+ by <url id="http://dehs.alioth.debian.org/"> and other Debian QA
+ tools to help with quality control and maintenance of the
distribution as a whole.
</p>
putting the name in round brackets and moving it to the
end, and bringing the email address forward).
</p>
+
+ <p>
+ See <ref id="maintainer"> for additional requirements and
+ information about package maintainers.
+ </p>
</sect1>
<sect1 id="f-Uploaders">
<heading><tt>Uploaders</tt></heading>
<p>
- List of the names and email addresses of co-maintainers of
- the package, if any. If the package has other maintainers
- beside the one named in the
- <qref id="f-Maintainer">Maintainer field</qref>, their names
- and email addresses should be listed here. The format of each
- entry is the same as that of the Maintainer field, and
- multiple entries must be comma separated. This is an optional
- field.
+ List of the names and email addresses of co-maintainers of the
+ package, if any. If the package has other maintainers besides
+ the one named in the <qref id="f-Maintainer">Maintainer
+ field</qref>, their names and email addresses should be listed
+ here. The format of each entry is the same as that of the
+ Maintainer field, and multiple entries must be comma
+ separated.
+ </p>
+
+ <p>
+ This is normally an optional field, but if
+ the <tt>Maintainer</tt> control field names a group of people
+ and a shared email address, the <tt>Uploaders</tt> field must
+ be present and must contain at least one human with their
+ personal email address.
</p>
<p>
</p>
<p>
- These scripts are the files <prgn>preinst</prgn>,
- <prgn>postinst</prgn>, <prgn>prerm</prgn> and
- <prgn>postrm</prgn> in the control area of the package.
- They must be proper executable files; if they are scripts
- (which is recommended), they must start with the usual
- <tt>#!</tt> convention. They should be readable and
+ These scripts are the control information
+ files <prgn>preinst</prgn>, <prgn>postinst</prgn>, <prgn>prerm</prgn>
+ and <prgn>postrm</prgn>. They must be proper executable files;
+ if they are scripts (which is recommended), they must start with
+ the usual <tt>#!</tt> convention. They should be readable and
executable by anyone, and must not be world-writable.
</p>
they exit with a zero status if everything went well.
</p>
- Additionally, packages interacting with users using
- <tt>debconf</tt> in the <prgn>postinst</prgn> script should
- install a <prgn>config</prgn> script in the control area,
- see <ref id="maintscriptprompt"> for details.
- </p>
+ <p>
+ Additionally, packages interacting with users
+ using <prgn>debconf</prgn> in the <prgn>postinst</prgn> script
+ should install a <prgn>config</prgn> script as a control
+ information file. See <ref id="maintscriptprompt"> for details.
+ </p>
<p>
When a package is upgraded a combination of the scripts from
In the <tt>Depends</tt>, <tt>Recommends</tt>,
<tt>Suggests</tt>, <tt>Pre-Depends</tt>,
<tt>Build-Depends</tt> and <tt>Build-Depends-Indep</tt>
- control file fields of the package, which declare
+ control fields of the package, which declare
dependencies on other packages, the package names listed may
also include lists of alternative package names, separated
by vertical bar (pipe) symbols <tt>|</tt>. In such a case,
<p>
This is done using the <tt>Depends</tt>, <tt>Pre-Depends</tt>,
<tt>Recommends</tt>, <tt>Suggests</tt>, <tt>Enhances</tt>,
- <tt>Breaks</tt> and <tt>Conflicts</tt> control file fields.
+ <tt>Breaks</tt> and <tt>Conflicts</tt> control fields.
<tt>Breaks</tt> is described in <ref id="breaks">, and
<tt>Conflicts</tt> is described in <ref id="conflicts">. The
rest are described below.
<p>
A <em>virtual package</em> is one which appears in the
- <tt>Provides</tt> control file field of another package.
- The effect is as if the package(s) which provide a
- particular virtual package name had been listed by name
- everywhere the virtual package name appears. (See also <ref
- id="virtual_pkg">)
+ <tt>Provides</tt> control field of another package. The effect
+ is as if the package(s) which provide a particular virtual
+ package name had been listed by name everywhere the virtual
+ package name appears. (See also <ref id="virtual_pkg">)
</p>
<p>
<p>
Packages can declare in their control file that they should
- overwrite files in certain other packages, or completely
- replace other packages. The <tt>Replaces</tt> control file
- field has these two distinct purposes.
+ overwrite files in certain other packages, or completely replace
+ other packages. The <tt>Replaces</tt> control field has these
+ two distinct purposes.
</p>
<sect1><heading>Overwriting files in other packages</heading>
<p>
This is done using the <tt>Build-Depends</tt>,
<tt>Build-Depends-Indep</tt>, <tt>Build-Conflicts</tt> and
- <tt>Build-Conflicts-Indep</tt> control file fields.
+ <tt>Build-Conflicts-Indep</tt> control fields.
</p>
<p>
<p>
There is no Build-Depends-Arch; this role is essentially
met with Build-Depends. Anyone building the
- <tt>build-indep</tt> and binary-indep<tt></tt> targets is
+ <tt>build-indep</tt> and <tt>binary-indep</tt> targets is
assumed to be building the whole package, and therefore
installation of all build dependencies is required.
</p>
</p>
<p>
- Packages involving shared libraries should be split up into
- several binary packages. This section mostly deals with how
- this separation is to be accomplished; rules for files within
- the shared library packages are in <ref id="libraries"> instead.
+ This section deals only with public shared libraries: shared
+ libraries that are placed in directories searched by the dynamic
+ linker by default or which are intended to be linked against
+ normally and possibly used by other, independent packages. Shared
+ libraries that are internal to a particular package or that are
+ only loaded as dynamic modules are not covered by this section and
+ are not subject to its requirements.
</p>
- <sect id="sharedlibs-runtime">
- <heading>Run-time shared libraries</heading>
+ <p>
+ A shared library is identified by the <tt>SONAME</tt> attribute
+ stored in its dynamic section. When a binary is linked against a
+ shared library, the <tt>SONAME</tt> of the shared library is
+ recorded in the binary's <tt>NEEDED</tt> section so that the
+ dynamic linker knows that library must be loaded at runtime. The
+ shared library file's full name (which usually contains additional
+ version information not needed in the <tt>SONAME</tt>) is
+ therefore normally not referenced directly. Instead, the shared
+ library is loaded by its <tt>SONAME</tt>, which exists on the file
+ system as a symlink pointing to the full name of the shared
+ library. This symlink must be provided by the
+ package. <ref id="sharedlibs-runtime"> describes how to do this.
+ <footnote>
+ This is a convention of shared library versioning, but not a
+ requirement. Some libraries use the <tt>SONAME</tt> as the full
+ library file name instead and therefore do not need a symlink.
+ Most, however, encode additional information about
+ backwards-compatible revisions as a minor version number in the
+ file name. The <tt>SONAME</tt> itself only changes when
+ binaries linked with the earlier version of the shared library
+ may no longer work, but the filename may change with each
+ release of the library. See <ref id="sharedlibs-runtime"> for
+ more information.
+ </footnote>
+ </p>
<p>
- The run-time shared library needs to be placed in a package
- whose name changes whenever the shared object version
- changes.<footnote>
- <p>
- Since it is common place to install several versions of a
- package that just provides shared libraries, it is a
- good idea that the library package should not
- contain any extraneous non-versioned files, unless they
- happen to be in versioned directories.</p>
- </footnote>
- The most common mechanism is to place it in a package
- called
- <package><var>libraryname</var><var>soversion</var></package>,
- where <file><var>soversion</var></file> is the version number
- in the soname of the shared library<footnote>
- The soname is the shared object name: it's the thing
- that has to match exactly between building an executable
- and running it for the dynamic linker to be able run the
- program. For example, if the soname of the library is
- <file>libfoo.so.6</file>, the library package would be
- called <file>libfoo6</file>.
- </footnote>.
- Alternatively, if it would be confusing to directly append
- <var>soversion</var> to <var>libraryname</var> (e.g. because
- <var>libraryname</var> itself ends in a number), you may use
- <package><var>libraryname</var>-<var>soversion</var></package> and
- <package><var>libraryname</var>-<var>soversion</var>-dev</package>
- instead.
+ When linking a binary or another shared library against a shared
+ library, the <tt>SONAME</tt> for that shared library is not yet
+ known. Instead, the shared library is found by looking for a file
+ matching the library name with <tt>.so</tt> appended. This file
+ exists on the file system as a symlink pointing to the shared
+ library.
</p>
<p>
- If you have several shared libraries built from the same
- source tree you may lump them all together into a single
- shared library package, provided that you change all of
- their sonames at once (so that you don't get filename
- clashes if you try to install different versions of the
- combined shared libraries package).
+ Shared libraries are normally split into several binary packages.
+ The <tt>SONAME</tt> symlink is installed by the runtime shared
+ library package, and the bare <tt>.so</tt> symlink is installed in
+ the development package since it's only used when linking binaries
+ or shared libraries. However, there are some exceptions for
+ unusual shared libraries or for shared libraries that are also
+ loaded as dynamic modules by other programs.
</p>
+ <p>
+ This section is primarily concerned with how the separation of
+ shared libraries into multiple packages should be done and how
+ dependencies on and between shared library binary packages are
+ managed in Debian. <ref id="libraries"> should be read in
+ conjunction with this section and contains additional rules for
+ the files contained in the shared library packages.
+ </p>
+
+ <sect id="sharedlibs-runtime">
+ <heading>Run-time shared libraries</heading>
+
+ <p>
+ The run-time shared library must be placed in a package
+ whose name changes whenever the <tt>SONAME</tt> of the shared
+ library changes. This allows several versions of the shared
+ library to be installed at the same time, allowing installation
+ of the new version of the shared library without immediately
+ breaking binaries that depend on the old version. Normally, the
+ run-time shared library and its <tt>SONAME</tt> symlink should
+ be placed in a package named
+ <package><var>libraryname</var><var>soversion</var></package>,
+ where <var>soversion</var> is the version number in
+ the <tt>SONAME</tt> of the shared library.
+ See <ref id="shlibs"> for detailed information on how to
+ determine this version. Alternatively, if it would be confusing
+ to directly append <var>soversion</var>
+ to <var>libraryname</var> (if, for example, <var>libraryname</var>
+ itself ends in a number), you should use
+ <package><var>libraryname</var>-<var>soversion</var></package>
+ instead.
+ </p>
+
+ <p>
+ If you have several shared libraries built from the same source
+ tree, you may lump them all together into a single shared
+ library package provided that all of their <tt>SONAME</tt>s will
+ always change together. Be aware that this is not normally the
+ case, and if the <tt>SONAME</tt>s do not change together,
+ upgrading such a merged shared library package will be
+ unnecessarily difficult because of file conflicts with the old
+ version of the package. When in doubt, always split shared
+ library packages so that each binary package installs a single
+ shared library.
+ </p>
+
+ <p>
+ Every time the shared library ABI changes in a way that may
+ break binaries linked against older versions of the shared
+ library, the <tt>SONAME</tt> of the library and the
+ corresponding name for the binary package containing the runtime
+ shared library should change. Normally, this means
+ the <tt>SONAME</tt> should change any time an interface is
+ removed from the shared library or the signature of an interface
+ (the number of parameters or the types of parameters that it
+ takes, for example) is changed. This practice is vital to
+ allowing clean upgrades from older versions of the package and
+ clean transitions between the old ABI and new ABI without having
+ to upgrade every affected package simultaneously.
+ </p>
+
+ <p>
+ The <tt>SONAME</tt> and binary package name need not, and indeed
+ normally should not, change if new interfaces are added but none
+ are removed or changed, since this will not break binaries
+ linked against the old shared library. Correct versioning of
+ dependencies on the newer shared library by binaries that use
+ the new interfaces is handled via
+ the <qref id="sharedlibs-shlibdeps"><tt>shlibs</tt>
+ system</qref> or via symbols files (see
+ <manref name="deb-symbols" section="5">).
+ </p>
+
<p>
The package should install the shared libraries under
their normal names. For example, the <package>libgdbm3</package>
</p>
<p>
- The run-time library package should include the symbolic link that
- <prgn>ldconfig</prgn> would create for the shared libraries.
- For example, the <package>libgdbm3</package> package should include
- a symbolic link from <file>/usr/lib/libgdbm.so.3</file> to
+ The run-time library package should include the symbolic link for
+ the <tt>SONAME</tt> that <prgn>ldconfig</prgn> would create for
+ the shared libraries. For example,
+ the <package>libgdbm3</package> package should include a symbolic
+ link from <file>/usr/lib/libgdbm.so.3</file> to
<file>libgdbm.so.3.0.0</file>. This is needed so that the dynamic
linker (for example <prgn>ld.so</prgn> or
<prgn>ld-linux.so.*</prgn>) can find the library between the
library directories of the dynamic linker (which are currently
<file>/usr/lib</file> and <file>/lib</file>) or a directory that is
listed in <file>/etc/ld.so.conf</file><footnote>
- These are currently
- <list compact="compact">
- <item>/usr/local/lib</item>
- <item>/usr/lib/libc5-compat</item>
- <item>/lib/libc5-compat</item>
- </list>
+ These are currently <file>/usr/local/lib</file> plus
+ directories under <file>/lib</file> and <file>/usr/lib</file>
+ matching the multiarch triplet for the system architecture.
</footnote>
must use <prgn>ldconfig</prgn> to update the shared library
system.
(<prgn>ld</prgn>) when compiling packages, as it will only look for
<file>libgdbm.so</file> when compiling dynamically.
</p>
+
+ <p>
+ If the package provides Ada Library Information
+ (<file>*.ali</file>) files for use with GNAT, these files must be
+ installed read-only (mode 0444) so that GNAT will not attempt to
+ recompile them. This overrides the normal file mode requirements
+ given in <ref id="permissions-owners">.
+ </p>
</sect>
<sect id="sharedlibs-intradeps">
<p>
When packages are being built,
any <file>debian/shlibs</file> files are copied into the
- control file area of the temporary build directory and
- given the name <file>shlibs</file>. These files give
- details of any shared libraries included in the same
- package.<footnote>
+ control information file area of the temporary build
+ directory and given the name <file>shlibs</file>. These
+ files give details of any shared libraries included in the
+ same package.<footnote>
An example may help here. Let us say that the source
package <tt>foo</tt> generates two binary
packages, <tt>libfoo2</tt> and <tt>foo-runtime</tt>.
It is usual to call this file <file>debian/shlibs</file> (but if
you have multiple binary packages, you might want to call it
<file>debian/shlibs.<var>package</var></file> instead). Then
- let <file>debian/rules</file> install it in the control area:
+ let <file>debian/rules</file> install it in the control
+ information file area:
<example compact="compact">
install -m644 debian/shlibs debian/tmp/DEBIAN
</example>
install -m644 debian/shlibs.<var>package</var> debian/<var>package</var>/DEBIAN/shlibs
</example>
An alternative way of doing this is to create the
- <file>shlibs</file> file in the control area directly from
- <file>debian/rules</file> without using a <file>debian/shlibs</file>
- file at all,<footnote>
+ <file>shlibs</file> file in the control information file area
+ directly from <file>debian/rules</file> without using
+ a <file>debian/shlibs</file> file at all,<footnote>
This is what <prgn>dh_makeshlibs</prgn> in
the <package>debhelper</package> suite does. If your package
also has a udeb that provides a shared
to get access to kernel information.</footnote>
</p>
</item>
+ <item>
+ <p>
+ On GNU/Hurd systems, the following additional
+ directories are allowed in the root
+ filesystem: <file>/hurd</file>
+ and <file>/servers</file>.<footnote>
+ These directories are used to store translators and as
+ a set of standard names for mount points,
+ respectively.
+ </footnote>
+ </p>
+ </item>
</enumlist>
-
</p>
+
<p>
The version of this document referred here can be
found in the <tt>debian-policy</tt> package or on <url
<item>The XSI extension to <prgn>trap</prgn> allowing numeric
signals must be supported. In addition to the signal
numbers listed in the extension, which are the same as for
- <prgn>kill<prgn> above, 13 (SIGPIPE) must be allowed.
+ <prgn>kill</prgn> above, 13 (SIGPIPE) must be allowed.
</item>
</list>
If a shell script requires non-SUSv3 features from the shell
</p>
<p>
- Log files must be rotated occasionally so that they don't
- grow indefinitely; the best way to do this is to drop a log
- rotation configuration file into the directory
- <file>/etc/logrotate.d</file> and use the facilities provided by
- logrotate.<footnote>
+ Log files must be rotated occasionally so that they don't grow
+ indefinitely. The best way to do this is to install a log
+ rotation configuration file in the
+ directory <file>/etc/logrotate.d</file>, normally
+ named <file>/etc/logrotate.d/<var>package</var></file>, and use
+ the facilities provided by <prgn>logrotate</prgn>.
+ <footnote>
<p>
The traditional approach to log files has been to set up
<em>ad hoc</em> log rotation schemes using simple shell
section="8">):
<example compact="compact">
/var/log/foo/*.log {
-rotate 12
-weekly
-compress
-postrotate
-/etc/init.d/foo force-reload
-endscript
+ rotate 12
+ weekly
+ compress
+ missingok
+ postrotate
+ start-stop-daemon -K -p /var/run/foo.pid -s HUP -x /usr/sbin/foo -q
+ endscript
}
</example>
This rotates all files under <file>/var/log/foo</file>, saves 12
- compressed generations, and forces the daemon to reload its
- configuration information after the log rotation.
+ compressed generations, and tells the daemon to reopen its log
+ files after the log rotation. It skips this log rotation
+ (via <tt>missingok</tt>) if no such log file is present, which
+ avoids errors if the package is removed but not purged.
</p>
<p>
</p>
</sect>
- <sect>
+ <sect id="permissions-owners">
<heading>Permissions and owners</heading>
<p>
</footnote>
</p>
+ <p>
+ Control information files should be owned by <tt>root:root</tt>
+ and either mode 644 (for most files) or mode 755 (for
+ executables such as <qref id="maintscripts">maintainer
+ scripts</qref>).
+ </p>
<p>
Setuid and setgid executables should be mode 4755 or 2755
<p>
These two files are managed through the <prgn>dpkg</prgn>
- "alternatives" mechanism. Thus every package providing an
- editor or pager must call the
- <prgn>update-alternatives</prgn> script to register these
- programs.
+ "alternatives" mechanism. Every package providing an editor or
+ pager must call the <prgn>update-alternatives</prgn> script to
+ register as an alternative for <file>/usr/bin/editor</file>
+ or <file>/usr/bin/pager</file> as appropriate. The alternative
+ should have a slave alternative
+ for <file>/usr/share/man/man1/editor.1.gz</file>
+ or <file>/usr/share/man/man1/pager.1.gz</file> pointing to the
+ corresponding manual page.
</p>
<p>
this so programs should not fail if <prgn>newaliases</prgn>
cannot be found. Note that because of this, all MTA
packages must have <tt>Provides</tt>, <tt>Conflicts</tt> and
- <tt>Replaces: mail-transport-agent</tt> control file
- fields.
+ <tt>Replaces: mail-transport-agent</tt> control fields.
</p>
<p>
<p>
Packages that provide an X server that, directly or
indirectly, communicates with real input and display
- hardware should declare in their control data that they
- provide the virtual package <tt>xserver</tt>.<footnote>
+ hardware should declare in their <tt>Provides</tt> control
+ field that they provide the virtual
+ package <tt>xserver</tt>.<footnote>
This implements current practice, and provides an
actual policy for usage of the <tt>xserver</tt>
virtual package which appears in the virtual packages
<p>
Packages that provide a terminal emulator for the X Window
- System which meet the criteria listed below should declare
- in their control data that they provide the virtual
- package <tt>x-terminal-emulator</tt>. They should also
- register themselves as an alternative for
+ System which meet the criteria listed below should declare in
+ their <tt>Provides</tt> control field that they provide the
+ virtual package <tt>x-terminal-emulator</tt>. They should
+ also register themselves as an alternative for
<file>/usr/bin/x-terminal-emulator</file>, with a priority of
- 20.
+ 20. That alternative should have a slave alternative
+ for <file>/usr/share/man/man1/x-terminal-emulator.1.gz</file>
+ pointing to the corresponding manual page.
</p>
<p>
<p>
Packages that provide a window manager should declare in
- their control data that they provide the virtual package
- <tt>x-window-manager</tt>. They should also register
- themselves as an alternative for
+ their <tt>Provides</tt> control field that they provide the
+ virtual package <tt>x-window-manager</tt>. They should also
+ register themselves as an alternative for
<file>/usr/bin/x-window-manager</file>, with a priority
calculated as follows:
<list compact="compact">
configuration, add 10 points; otherwise add none.
</item>
</list>
+ That alternative should have a slave alternative
+ for <file>/usr/share/man/man1/x-window-manager.1.gz</file>
+ pointing to the corresponding manual page.
</p>
</sect1>
<item>
Font packages must declare a dependency on
- <tt>xfonts-utils</tt> in their control
- data.
+ <tt>xfonts-utils</tt> in their <tt>Depends</tt>
+ or <tt>Pre-Depends</tt> control field.
</item>
<item>
<p>
Packages in the <em>contrib</em> or <em>non-free</em> archive
areas should state in the copyright file that the package is not
- part of the Debian GNU/Linux distribution and briefly explain
- why.
+ part of the Debian distribution and briefly explain why.
</p>
<p>
<prgn>dpkg</prgn> is a suite of programs for creating binary
package files and installing and removing them on Unix
systems.<footnote>
- <prgn>dpkg</prgn> is targeted primarily at Debian
- GNU/Linux, but may work on or be ported to other
- systems.
+ <prgn>dpkg</prgn> is targeted primarily at Debian, but may
+ work on or be ported to other systems.
</footnote>
</p>
<p>
It is possible to put other files in the package control
- area, but this is not generally a good idea (though they
- will largely be ignored).
+ information file area, but this is not generally a good idea
+ (though they will largely be ignored).
</p>
<p>
- Here is a brief list of the control info files supported by
- <prgn>dpkg</prgn> and a summary of what they're used for.
+ Here is a brief list of the control information files supported
+
by <prgn>dpkg</prgn> and a summary of what they're used for.
</p>
<p>
<tag><tt>Package_Revision</tt></tag>
<item>
The Debian revision part of the package version was
- at one point in a separate control file field. This
+ at one point in a separate control field. This
field went through several names.
</item>
</heading>
<p>
- A package may contain a control area file called
+ A package may contain a control information file called
<tt>conffiles</tt>. This file should be a list of filenames
of configuration files needing automatic handling, separated
by newlines. The filenames should be absolute pathnames,
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