<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
The actual editing is done by a group of maintainers that have
no editorial powers. These are the current maintainers:
- <enumlist>
- <item>Julian Gilbey</item>
- <item>Branden Robinson</item>
- <item>Josip Rodin</item>
- <item>Manoj Srivastava</item>
- </enumlist>
+ <enumlist>
+ <item>Russ Allbery</item>
+ <item>Bill Allombert</item>
+ <item>Andrew McMillan</item>
+ <item>Manoj Srivastava</item>
+ <item>Colin Watson</item>
+ </enumlist>
</p>
<p>
<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>
<sect1 id="main">
<heading>The main archive area</heading>
+ <p>
+ The <em>main</em> archive area comprises the Debian
+ distribution. Only the packages in this area are considered
+ part of the distribution. None of the packages in
+ the <em>main</em> archive area require software outside of
+ that area to function. Anyone may use, share, modify and
+ redistribute the packages in this archive area
+ freely<footnote>
+ See <url id="http://www.debian.org/intro/free"
+ name="What Does Free Mean?"> for
+ more about what we mean by free software.
+ </footnote>.
+ </p>
+
<p>
Every package in <em>main</em> must comply with the DFSG
(Debian Free Software Guidelines).
<sect1 id="contrib">
<heading>The contrib archive area</heading>
+ <p>
+ The <em>contrib</em> archive area contains supplemental
+ packages intended to work with the Debian distribution, but
+ which require software outside of the distribution to either
+ build or function.
+ </p>
+
<p>
Every package in <em>contrib</em> must comply with the DFSG.
</p>
</list>
</p>
-
<p>
Examples of packages which would be included in
<em>contrib</em> are:
<sect1 id="non-free">
<heading>The non-free archive area</heading>
+ <p>
+ The <em>non-free</em> archive area contains supplemental
+ packages intended to work with the Debian distribution that do
+ not comply with the DFSG or have other problems that make
+ their distribution problematic. They may not comply with all
+ of the policy requirements in this manual due to restrictions
+ on modifications or other limitations.
+ </p>
+
<p>
Packages must be placed in <em>non-free</em> if they are
not compliant with the DFSG or are encumbered by patents
<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.
<heading>The maintainer of a package</heading>
<p>
- Every package must have a 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 maintaining the Debian packaging files, evaluating and
+ 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
</p>
<p>
- If the maintainer of a package no longer has time or desire to
- maintain a package, it should be orphaned according to the
- procedure described in the Debian Developer's Reference
- (see <ref id="related">). The maintainer then
- becomes <tt>Debian QA Group <packages@qa.debian.org></tt>.
+ 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.
+ 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>
</sect>
- <sect>
+ <sect id="dependencies">
<heading>Dependencies</heading>
<p>
</p>
<p>
- Sometimes, a package requires another package to be installed
- <em>and</em> configured before it can be installed. In this
- case, you must specify a <tt>Pre-Depends</tt> entry for
- the package.
+ Sometimes, unpacking one package requires that another package
+ be first unpacked <em>and</em> configured. In this case, the
+ depending package must specify this dependency in
+ the <tt>Pre-Depends</tt> control field.
</p>
<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.
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>
<item><qref id="f-Source"><tt>Source</tt></qref> (mandatory)</item>
<item><qref id="f-Maintainer"><tt>Maintainer</tt></qref> (mandatory)</item>
<item><qref id="f-Uploaders"><tt>Uploaders</tt></qref></item>
+ <item><qref id="f-DM-Upload-Allowed"><tt>DM-Upload-Allowed</tt></qref></item>
<item><qref id="f-Section"><tt>Section</tt></qref> (recommended)</item>
<item><qref id="f-Priority"><tt>Priority</tt></qref> (recommended)</item>
<item><qref id="sourcebinarydeps"><tt>Build-Depends</tt> et al</qref></item>
<item><qref id="f-Version"><tt>Version</tt></qref> (mandatory)</item>
<item><qref id="f-Maintainer"><tt>Maintainer</tt></qref> (mandatory)</item>
<item><qref id="f-Uploaders"><tt>Uploaders</tt></qref></item>
+ <item><qref id="f-DM-Upload-Allowed"><tt>DM-Upload-Allowed</tt></qref></item>
<item><qref id="f-Homepage"><tt>Homepage</tt></qref></item>
<item><qref id="f-Standards-Version"><tt>Standards-Version</tt></qref> (recommended)</item>
<item><qref id="sourcebinarydeps"><tt>Build-Depends</tt> et al</qref></item>
must match the list of files in the <tt>Files</tt> field.
</p>
</sect1>
+
+ <sect1 id="f-DM-Upload-Allowed">
+ <heading><tt>DM-Upload-Allowed</tt></heading>
+
+ <p>
+ The most recent version of a package uploaded to unstable or
+ experimental must include the field <tt>DM-Upload-Allowed:
+ yes</tt> in the source section of its source control file for
+ the Debian archive to accept uploads signed with a key in the
+ Debian Maintainer keyring. See the General
+ Resolution <url id="http://www.debian.org/vote/2007/vote_003"
+ name="Endorse the concept of Debian Maintainers"> for more
+ details.
+ </p>
+ </sect1>
</sect>
<sect>
<p>
Broadly speaking the <prgn>preinst</prgn> is called before
- (a particular version of) a package is installed, and the
+ (a particular version of) a package is unpacked, and the
<prgn>postinst</prgn> afterwards; the <prgn>prerm</prgn>
before (a version of) a package is removed and the
<prgn>postrm</prgn> afterwards.
</heading>
<p>
- <list compact="compact">
- <item>
- <var>new-preinst</var> <tt>install</tt>
- </item>
- <item>
- <var>new-preinst</var> <tt>install</tt> <var>old-version</var>
- </item>
- <item>
- <var>new-preinst</var> <tt>upgrade</tt> <var>old-version</var>
- </item>
- <item>
- <var>old-preinst</var> <tt>abort-upgrade</tt>
- <var>new-version</var>
- </item>
- </list>
+ What follows is a summary of all the ways in which maintainer
+ scripts may be called along with what facilities those scripts
+ may rely on being available at that time. Script names preceded
+ by <var>new-</var> are the scripts from the new version of a
+ package being installed, upgraded to, or downgraded to. Script
+ names preceded by <var>old-</var> are the scripts from the old
+ version of a package that is being upgraded from or downgraded
+ from.
+ </p>
<p>
- <list compact="compact">
- <item>
- <var>postinst</var> <tt>configure</tt>
- <var>most-recently-configured-version</var>
- </item>
- <item>
- <var>old-postinst</var> <tt>abort-upgrade</tt>
- <var>new-version</var>
- </item>
- <item>
- <var>conflictor's-postinst</var> <tt>abort-remove</tt>
- <tt>in-favour</tt> <var>package</var>
- <var>new-version</var>
- </item>
+ The <prgn>preinst</prgn> script may be called in the following
+ ways:
+ <taglist>
+ <tag><var>new-preinst</var> <tt>install</tt></tag>
+ <tag><var>new-preinst</var> <tt>install</tt>
+ <var>old-version</var></tag>
+ <tag><var>new-preinst</var> <tt>upgrade</tt>
+ <var>old-version</var></tag>
<item>
- <var>postinst</var> <tt>abort-remove</tt>
+ The package will not yet be unpacked, so
+ the <prgn>preinst</prgn> script cannot rely on any files
+ included in its package. Only essential packages and
+ pre-dependencies (<tt>Pre-Depends</tt>) may be assumed to be
+ available. Pre-dependencies will have been configured at
+ least once, but at the time the <prgn>preinst</prgn> is
+ called they may only be in an unpacked or "Half-Configured"
+ state if a previous version of the pre-dependency was
+ completely configured and has not been removed since then.
</item>
+
+ <tag><var>old-preinst</var> <tt>abort-upgrade</tt>
+ <var>new-version</var></tag>
<item>
- <var>deconfigured's-postinst</var>
- <tt>abort-deconfigure</tt> <tt>in-favour</tt>
- <var>failed-install-package</var> <var>version</var>
- [<tt>removing</tt> <var>conflicting-package</var>
- <var>version</var>]
+ Called during error handling of an upgrade that failed after
+ unpacking the new package because the <tt>postrm
+ upgrade</tt> action failed. The unpacked files may be
+ partly from the new version or partly missing, so the script
+ cannot rely on files included in the package. Package
+ dependencies may not be available. Pre-dependencies will be
+ at least unpacked following the same rules as above, except
+ they may be only "Half-Installed" if an upgrade of the
+ pre-dependency failed.<footnote>
+ This can happen if the new version of the package no
+ longer pre-depends on a package that had been partially
+ upgraded.
+ </footnote>
</item>
- </list>
+ </taglist>
+ </p>
<p>
- <list compact="compact">
- <item>
- <var>prerm</var> <tt>remove</tt>
- </item>
- <item>
- <var>old-prerm</var> <tt>upgrade</tt>
- <var>new-version</var>
- </item>
- <item>
- <var>new-prerm</var> <tt>failed-upgrade</tt>
- <var>old-version</var>
- </item>
+ The <prgn>postinst</prgn> script may be called in the following
+ ways:
+ <taglist>
+ <tag><var>postinst</var> <tt>configure</tt>
+ <var>most-recently-configured-version</var></tag>
<item>
- <var>conflictor's-prerm</var> <tt>remove</tt>
- <tt>in-favour</tt> <var>package</var>
- <var>new-version</var>
+ The files contained in the package will be unpacked. All
+ package dependencies will at least be unpacked. If there
+ are no circular dependencies involved, all package
+ dependencies will be configured. For behavior in the case
+ of circular dependencies, see the discussion
+ in <ref id="binarydeps">.
</item>
+
+ <tag><var>old-postinst</var> <tt>abort-upgrade</tt>
+ <var>new-version</var></tag>
+ <tag><var>conflictor's-postinst</var> <tt>abort-remove</tt>
+ <tt>in-favour</tt> <var>package</var>
+ <var>new-version</var></tag>
+ <tag><var>postinst</var> <tt>abort-remove</tt></tag>
+ <tag><var>deconfigured's-postinst</var>
+ <tt>abort-deconfigure</tt> <tt>in-favour</tt>
+ <var>failed-install-package</var> <var>version</var>
+ [<tt>removing</tt> <var>conflicting-package</var>
+ <var>version</var>]</tag>
<item>
- <var>deconfigured's-prerm</var> <tt>deconfigure</tt>
- <tt>in-favour</tt> <var>package-being-installed</var>
- <var>version</var> [<tt>removing</tt>
- <var>conflicting-package</var>
- <var>version</var>]
+ The files contained in the package will be unpacked. All
+ package dependencies will at least be "Half-Installed" and
+ will have previously been configured and not removed.
+ However, dependencies may not be configured or even fully
+ unpacked in some error situations.<footnote>
+ For example, suppose packages foo and bar are installed
+ with foo depending on bar. If an upgrade of bar were
+ started and then aborted, and then an attempt to remove
+ foo failed because its <prgn>prerm</prgn> script failed,
+ foo's <tt>postinst abort-remove</tt> would be called with
+ bar only "Half-Installed".
+ </footnote>
+ The <prgn>postinst</prgn> should still attempt any actions
+ for which its dependencies are required, since they will
+ normally be available, but consider the correct error
+ handling approach if those actions fail. Aborting
+ the <prgn>postinst</prgn> action if commands or facilities
+ from the package dependencies are not available is often the
+ best approach.
</item>
- </list>
+ </taglist>
+ </p>
<p>
- <list compact="compact">
- <item>
- <var>postrm</var> <tt>remove</tt>
- </item>
- <item>
- <var>postrm</var> <tt>purge</tt>
- </item>
- <item>
- <var>old-postrm</var> <tt>upgrade</tt>
- <var>new-version</var>
- </item>
+ The <prgn>prerm</prgn> script may be called in the following
+ ways:
+ <taglist>
+ <tag><var>prerm</var> <tt>remove</tt></tag>
+ <tag><var>old-prerm</var>
+ <tt>upgrade</tt><var>new-version</var></tag>
+ <tag><var>conflictor's-prerm</var> <tt>remove</tt>
+ <tt>in-favour</tt> <var>package</var>
+ <var>new-version</var></tag>
+ <tag><var>deconfigured's-prerm</var> <tt>deconfigure</tt>
+ <tt>in-favour</tt> <var>package-being-installed</var>
+ <var>version</var> [<tt>removing</tt>
+ <var>conflicting-package</var> <var>version</var>]</tag>
<item>
- <var>new-postrm</var> <tt>failed-upgrade</tt>
- <var>old-version</var>
+ The package whose <prgn>prerm</prgn> is being called will be
+ at least "Half-Installed". All package dependencies will at
+ least be "Half-Installed" and will have previously been
+ configured and not removed. If there was no error, all
+ dependencies will at least be unpacked, but these actions
+ may be called in various error states where dependencies are
+ only "Half-Installed" due to a partial upgrade.
</item>
+
+ <tag><var>new-prerm</var> <tt>failed-upgrade</tt>
+ <var>old-version</var></tag>
<item>
- <var>new-postrm</var> <tt>abort-install</tt>
+ Called during error handling when <tt>prerm upgrade</tt>
+ fails. The new package will not yet be unpacked, and all
+ the same constraints as for <tt>preinst upgrade</tt> apply.
</item>
+ </taglist>
+ </p>
+
+ <p>
+ The <prgn>postrm</prgn> script may be called in the following
+ ways:
+ <taglist>
+ <tag><var>postrm</var> <tt>remove</tt></tag>
+ <tag><var>postrm</var> <tt>purge</tt></tag>
+ <tag><var>old-postrm</var> <tt>upgrade</tt>
+ <var>new-version</var></tag>
+ <tag><var>disappearer's-postrm</var> <tt>disappear</tt>
+ <var>overwriter</var> <var>overwriter-version</var></tag>
<item>
- <var>new-postrm</var> <tt>abort-install</tt>
- <var>old-version</var>
+ The <prgn>postrm</prgn> script is called after the package's
+ files have been removed or replaced. The package
+ whose <prgn>postrm</prgn> is being called may have
+ previously been deconfigured and only be unpacked, at which
+ point subsequent package changes do not consider its
+ dependencies. Therefore, all <prgn>postrm</prgn> actions
+ may only rely on essential packages and must gracefully skip
+ any actions that require the package's dependencies if those
+ dependencies are unavailable.<footnote>
+ This is often done by checking whether the command or
+ facility the <prgn>postrm</prgn> intends to call is
+ available before calling it. For example:
+<example>
+if [ "$1" = purge ] && [ -e /usr/share/debconf/confmodule ]; then
+ . /usr/share/debconf/confmodule
+ db_purge
+fi
+</example>
+ in <prgn>postrm</prgn> purges the <prgn>debconf</prgn>
+ configuration for the package
+ if <package>debconf</package> is installed.
+ </footnote>
</item>
+
+ <tag><var>new-postrm</var> <tt>failed-upgrade</tt>
+ <var>old-version</var></tag>
<item>
- <var>new-postrm</var> <tt>abort-upgrade</tt>
- <var>old-version</var>
+ Called when the old <tt>postrm upgrade</tt> action fails.
+ The new package will be unpacked, but only essential
+ packages and pre-dependencies can be relied on.
+ Pre-dependencies will either be configured or will be
+ "Unpacked" or "Half-Configured" but previously had been
+ configured and was never removed.
</item>
+
+ <tag><var>new-postrm</var> <tt>abort-install</tt></tag>
+ <tag><var>new-postrm</var> <tt>abort-install</tt>
+ <var>old-version</var></tag>
+ <tag><var>new-postrm</var> <tt>abort-upgrade</tt>
+ <var>old-version</var></tag>
<item>
- <var>disappearer's-postrm</var> <tt>disappear</tt>
- <var>overwriter</var>
- <var>overwriter-version</var>
+ Called before unpacking the new package as part of the
+ error handling of <prgn>preinst</prgn> failures. May assume
+ the same state as <prgn>preinst</prgn> can assume.
</item>
- </list>
+ </taglist>
</p>
-
+ </sect>
<sect id="unpackphase">
<heading>Details of unpack phase of installation or upgrade</heading>
behavior which, though deterministic, is hard for the
system administrator to understand. It can easily
lead to "missing" programs if, for example, a package
- is installed which overwrites a file from another
+ is unpacked which overwrites a file from another
package, and is then removed again.<footnote>
Part of the problem is due to what is arguably a
bug in <prgn>dpkg</prgn>.
If there was a conflicting package we go and do the
removal actions (described below), starting with the
removal of the conflicting package's files (any that
- are also in the package being installed have already
+ are also in the package being unpacked have already
been removed from the conflicting package's file list,
and so do not get removed now).
</item>
</p>
<p>
- For this reason packages in an installation run are usually
- all unpacked first and all configured later; this gives
- later versions of packages with dependencies on later
- versions of other packages the opportunity to have their
- dependencies satisfied.
+ Since <tt>Depends</tt> only places requirements on the order in
+ which packages are configured, packages in an installation run
+ are usually all unpacked first and all configured later.
+ <footnote>
+ This approach makes dependency resolution easier. If two
+ packages A and B are being upgraded, the installed package A
+ depends on exactly the installed package B, and the new
+ package A depends on exactly the new package B (a common
+ situation when upgrading shared libraries and their
+ corresponding development packages), satisfying the
+ dependencies at every stage of the upgrade would be
+ impossible. This relaxed restriction means that both new
+ packages can be unpacked together and then configured in their
+ dependency order.
+ </footnote>
</p>
- <p>
- In case of circular dependencies, since installation or
- removal order honoring the dependency order can't be
- established, dependency loops are broken at some point
- (based on rules below), and some packages may not be able to
- rely on their dependencies being present when being
- installed or removed, depending on which side of the break
- of the circular dependency loop they happen to be on. If one
- of the packages in the loop has no postinst script, then the
- cycle will be broken at that package, so as to ensure that
- all postinst scripts run with the dependencies properly
- configured if this is possible. Otherwise the breaking point
- is arbitrary.
- </p>
-
<p>
- The <tt>Depends</tt> field thus allows package maintainers
- to impose an order in which packages should be configured.
+ If there is a circular dependency among packages being installed
+ or removed, installation or removal order honoring the
+ dependency order is impossible, requiring the dependency loop be
+ broken at some point and the dependency requirements violated
+ for at least one package. Packages involved in circular
+ dependencies may not be able to rely on their dependencies being
+ configured before they themselves are configured, depending on
+ which side of the break of the circular dependency loop they
+ happen to be on. If one of the packages in the loop has
+ no <prgn>postinst</prgn> script, then the cycle will be broken
+ at that package; this ensures that all <prgn>postinst</prgn>
+ scripts are run with their dependencies properly configured if
+ this is possible. Otherwise the breaking point is arbitrary.
+ Packages should therefore avoid circular dependencies where
+ possible, particularly if they have <prgn>postinst</prgn>
+ scripts.
</p>
<p>
This declares an absolute dependency. A package will
not be configured unless all of the packages listed in
its <tt>Depends</tt> field have been correctly
- configured.
+ configured (unless there is a circular dependency as
+ described above).
</p>
<p>
<p>
The <tt>Depends</tt> field should also be used if the
- <prgn>postinst</prgn>, <prgn>prerm</prgn> or
- <prgn>postrm</prgn> scripts require the package to be
- present in order to run. Note, however, that the
- <prgn>postrm</prgn> cannot rely on any non-essential
- packages to be present during the <tt>purge</tt>
- phase.
+ <prgn>postinst</prgn> or <prgn>prerm</prgn> scripts
+ require the depended-on package to be unpacked or
+ configured in order to run. In the case of <tt>postinst
+ configure</tt>, the depended-on packages will be unpacked
+ and configured first. (If both packages are involved in a
+ dependency loop, this might not work as expected; see the
+ explanation a few paragraphs back.) In the case
+ of <prgn>prerm</prgn> or other <prgn>postinst</prgn>
+ actions, the package dependencies will normally be at
+ least unpacked, but they may be only "Half-Installed" if a
+ previous upgrade of the dependency failed.
+ </p>
+
+ <p>
+ Finally, the <tt>Depends</tt> field should be used if the
+ depended-on package is needed by the <prgn>postrm</prgn>
+ script to fully clean up after the package removal. There
+ is no guarantee that package dependencies will be
+ available when <prgn>postrm</prgn> is run, but the
+ depended-on package is more likely to be available if the
+ package declares a dependency (particularly in the case
+ of <tt>postrm remove</tt>). The <prgn>postrm</prgn>
+ script must gracefully skip actions that require a
+ dependency if that dependency isn't available.
+ </p>
</item>
<tag><tt>Recommends</tt></tag>
</p>
<p>
- When the package declaring a pre-dependency is about
- to be <em>configured</em>, the pre-dependency will be
- treated as a normal <tt>Depends</tt>, that is, it will
- be considered satisfied only if the depended-on
- package has been correctly configured.
+ When the package declaring a pre-dependency is about to
+ be <em>configured</em>, the pre-dependency will be treated
+ as a normal <tt>Depends</tt>. It will be considered
+ satisfied only if the depended-on package has been
+ correctly configured. However, unlike
+ with <tt>Depends</tt>, <tt>Pre-Depends</tt> does not
+ permit circular dependencies to be broken. If a circular
+ dependency is encountered while attempting to honor
+ <tt>Pre-Depends</tt>, the installation will be aborted.
+ </p>
+
+ <p>
+ <tt>Pre-Depends</tt> are also required if the
+ <prgn>preinst</prgn> script depends on the named package.
+ It is best to avoid this situation if possible.
</p>
<p>
</p>
<p>
- <tt>Pre-Depends</tt> are also required if the
- <prgn>preinst</prgn> script depends on the named
- package. It is best to avoid this situation if
- possible.
+ You should not specify a <tt>Pre-Depends</tt> entry for a
+ package before this has been discussed on the
+ <tt>debian-devel</tt> mailing list and a consensus about
+ doing that has been reached. See <ref id="dependencies">.
</p>
</item>
</taglist>
<p>
When one binary package declares that it breaks another,
<prgn>dpkg</prgn> will refuse to allow the package which
- declares <tt>Breaks</tt> be installed unless the broken
+ declares <tt>Breaks</tt> to be unpacked unless the broken
package is deconfigured first, and it will refuse to
allow the broken package to be reconfigured.
</p>
<heading>Conflicting binary packages - <tt>Conflicts</tt></heading>
<p>
- When one binary package declares a conflict with another
- using a <tt>Conflicts</tt> field, <prgn>dpkg</prgn> will
- refuse to allow them to be installed on the system at the
- same time. This is a stronger restriction than <tt>Breaks</tt>,
- which just prevents both packages from being configured at the
- same time. Conflicting packages cannot be unpacked on the
- system at the same time.
+ When one binary package declares a conflict with another using
+ a <tt>Conflicts</tt> field, <prgn>dpkg</prgn> will refuse to
+ allow them to be unpacked on the system at the same time. This
+ is a stronger restriction than <tt>Breaks</tt>, which prevents
+ the broken package from being configured while the breaking
+ package is in the "Unpacked" state but allows both packages to
+ be unpacked at the same time.
</p>
<p>
- If one package is to be installed, the other must be removed
- first. If the package being installed is marked as replacing
+ If one package is to be unpacked, the other must be removed
+ first. If the package being unpacked is marked as replacing
(see <ref id="replaces">, but note that <tt>Breaks</tt> should
normally be used in this case) the one on the system, or the one
on the system is marked as deselected, or both packages are
<item>when two packages provide the same file and will
continue to do so,</item>
<item>in conjunction with <tt>Provides</tt> when only one
- package providing a given virtual facility may be installed
+ package providing a given virtual facility may be unpacked
at a time (see <ref id="virtual">),</item>
<item>in other cases where one must prevent simultaneous
installation of two packages for reasons that are ongoing
Conflicts: mail-transport-agent
Replaces: mail-transport-agent
</example>
- ensuring that only one MTA can be installed at any one
+ ensuring that only one MTA can be unpacked at any one
time. See <ref id="virtual"> for more information about this
example.
</sect1>
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.
<footnote>
<p>
During install or upgrade, the preinst is called before
- the new files are installed, so calling "ldconfig" is
+ the new files are unpacked, so calling "ldconfig" is
pointless. The preinst of an existing package can also be
called if an upgrade fails. However, this happens during
the critical time when a shared libs may exist on-disk
<ref id="conflicts">) to ensure that the user only installs one
development version at a time (as different development versions are
likely to have the same header files in them, which would cause a
- filename clash if both were installed).
+ filename clash if both were unpacked).
</p>
<p>
(<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">
<file>/lib/<var>triplet</var></file> and
<file>/usr/lib/<var>triplet</var></file>, where
<tt><var>triplet</var></tt> is the value returned by
- <tt>dpkg-architecture -qDEB_HOST_GNU_TYPE</tt> for the
+ <tt>dpkg-architecture -qDEB_HOST_MULTIARCH</tt> for the
architecture of the package. Packages may <em>not</em>
install files to any <var>triplet</var> path other
than the one matching the architecture of that package;
for instance, an <tt>Architecture: amd64</tt> package
containing 32-bit x86 libraries may not install these
- libraries to <file>/usr/lib/i486-linux-gnu</file>.
+ libraries to <file>/usr/lib/i386-linux-gnu</file>.
<footnote>
This is necessary in order to reserve the directories for
use in cross-installation of library packages from other
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
</example>
must be supported and must set the value of <tt>c</tt> to
<tt>delta</tt>.
- </item>
+ </item>
+ <item>The XSI extension to <prgn>kill</prgn> allowing <tt>kill
+ -<var>signal</var></tt>, where <var>signal</var> is either
+ the name of a signal or one of the numeric signals listed in
+ the XSI extension (0, 1, 2, 3, 6, 9, 14, and 15), must be
+ supported if <prgn>kill</prgn> is implemented as a shell
+ built-in.
+ </item>
+ <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.
+ </item>
</list>
If a shell script requires non-SUSv3 features from the shell
interpreter other than those listed above, the appropriate shell
<sect1>
<heading>Sharing configuration files</heading>
- <p>
- Packages which specify the same file as a
- <tt>conffile</tt> must be tagged as <em>conflicting</em>
- with each other. (This is an instance of the general rule
- about not sharing files. Note that neither alternatives
- nor diversions are likely to be appropriate in this case;
- in particular, <prgn>dpkg</prgn> does not handle diverted
- <tt>conffile</tt>s well.)
- </p>
-
- <p>
- The maintainer scripts must not alter a <tt>conffile</tt>
- of <em>any</em> package, including the one the scripts
- belong to.
- </p>
-
<p>
If two or more packages use the same configuration file
and it is reasonable for both to be installed at the same
and which manages the shared configuration files. (The
<tt>sgml-base</tt> package is a good example.)
</p>
+
+ <p>
+ If the configuration file cannot be shared as described above,
+ the packages must be marked as conflicting with each other.
+ Two packages that specify the same file as
+ a <tt>conffile</tt> must conflict. This is an instance of the
+ general rule about not sharing files. Neither alternatives
+ nor diversions are likely to be appropriate in this case; in
+ particular, <prgn>dpkg</prgn> does not handle diverted
+ <tt>conffile</tt>s well.
+ </p>
+
+ <p>
+ When two packages both declare the same <tt>conffile</tt>, they
+ may see left-over configuration files from each other even
+ though they conflict with each other. If a user removes
+ (without purging) one of the packages and installs the other,
+ the new package will take over the <tt>conffile</tt> from the
+ old package. If the file was modified by the user, it will be
+ treated the same as any other locally
+ modified <tt>conffile</tt> during an upgrade.
+ </p>
+
+ <p>
+ The maintainer scripts must not alter a <tt>conffile</tt>
+ of <em>any</em> package, including the one the scripts
+ belong to.
+ </p>
</sect1>
<sect1>
</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
<item>
If the window manager complies with <url
- id="http://www.freedesktop.org/Standards/wm-spec"
+ id="http://www.freedesktop.org/wiki/Specifications/wm-spec"
name="The Window Manager Specification Project">,
- written by the <url id="http://www.freedesktop.org/"
+ written by the <url id="http://www.freedesktop.org/wiki/"
name="Free Desktop Group">, add 40 points.
</item>
maintainer of the package is allowed to write this bug report
themselves, if they so desire). Do not close the bug report
until a proper man page is available.<footnote>
- It is not very hard to write a man page. See the
+ It is not very hard to write a man page. See the
<url id="http://www.schweikhardt.net/man_page_howto.html"
name="Man-Page-HOWTO">,
- <manref name="man" section="7">, the examples
- created by <prgn>debmake</prgn> or <prgn>dh_make</prgn>,
-
the helper program <prgn>help2man</prgn>, or the
- directory <file>/usr/share/doc/man-db/examples</file>.
+ <manref name="man" section="7">, the examples created
+ by <prgn>dh_make</prgn>, the helper
+ program <prgn>help2man</prgn>, or the
+ directory <file>/usr/share/doc/man-db/examples</file>.
</footnote>
</p>
<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>
<p>
- The Debian version of the FSF's GNU hello program is provided
- as an example for people wishing to create Debian
- packages. The Debian <prgn>debmake</prgn> package is
- recommended as a very helpful tool in creating and maintaining
- Debian packages. However, while the tools and examples are
- helpful, they do not replace the need to read and follow the
- Policy and Programmer's Manual.</p>
+ The Debian version of the FSF's GNU hello program is provided as
+ an example for people wishing to create Debian packages. However,
+ while the examples are helpful, they do not replace the need to
+ read and follow the Policy and Programmer's Manual.</p>
</appendix>
<appendix id="pkg-binarypkg">
<p>
The <prgn>DEBIAN</prgn> directory will not appear in the
file system archive of the package, and so won't be installed
- by <prgn>dpkg</prgn> when the package is installed.
+ by <prgn>dpkg</prgn> when the package is unpacked.
</p>
<p>
projects / debian / debian-policy.git / blobdiff