In addition, the packages in <em>main</em>
<list compact="compact">
<item>
- must not require a package outside of <em>main</em>
- for compilation or execution (thus, the package must
- not declare a "Depends", "Recommends", or
+ must not require or recommend a package outside
+ of <em>main</em> for compilation or execution (thus, the
+ package must not declare a "Depends", "Recommends", or
"Build-Depends" relationship on a non-<em>main</em>
package),
</item>
list of sections. At present, they are:
<em>admin</em>, <em>cli-mono</em>, <em>comm</em>, <em>database</em>,
<em>devel</em>, <em>debug</em>, <em>doc</em>, <em>editors</em>,
- <em>electronics</em>, <em>embedded</em>, <em>fonts</em>,
- <em>games</em>, <em>gnome</em>, <em>graphics</em>, <em>gnu-r</em>,
- <em>gnustep</em>, <em>hamradio</em>, <em>haskell</em>,
- <em>httpd</em>, <em>interpreters</em>, <em>java</em>, <em>kde</em>,
- <em>kernel</em>, <em>libs</em>, <em>libdevel</em>, <em>lisp</em>,
- <em>localization</em>, <em>mail</em>, <em>math</em>, <em>misc</em>,
+ <em>education</em>, <em>electronics</em>, <em>embedded</em>,
+ <em>fonts</em>, <em>games</em>, <em>gnome</em>, <em>graphics</em>,
+ <em>gnu-r</em>, <em>gnustep</em>, <em>hamradio</em>, <em>haskell</em>,
+ <em>httpd</em>, <em>interpreters</em>, <em>introspection</em>,
+ <em>java</em>, <em>kde</em>, <em>kernel</em>, <em>libs</em>,
+ <em>libdevel</em>, <em>lisp</em>, <em>localization</em>,
+ <em>mail</em>, <em>math</em>, <em>metapackages</em>, <em>misc</em>,
<em>net</em>, <em>news</em>, <em>ocaml</em>, <em>oldlibs</em>,
<em>otherosfs</em>, <em>perl</em>, <em>php</em>, <em>python</em>,
<em>ruby</em>, <em>science</em>, <em>shells</em>, <em>sound</em>,
</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>
fields<footnote>
The paragraphs are also sometimes referred to as stanzas.
</footnote>.
- The paragraphs are separated by blank lines. Some control
+ The paragraphs are separated by empty lines. Parsers may accept
+ lines consisting solely of spaces and tabs as paragraph
+ separators, but control files should use empty lines. Some control
files allow only one paragraph; others allow several, in
which case each paragraph usually refers to a different
package. (For example, in source packages, the first
paragraph refers to the source package, and later paragraphs
- refer to binary packages generated from the source.)
+ refer to binary packages generated from the source.) The
+ ordering of the paragraphs in control files is significant.
</p>
<p>
Each paragraph consists of a series of data fields; each
field consists of the field name, followed by a colon and
- then the data/value associated with that field. It ends at
- the end of the (logical) line. Horizontal whitespace
+ then the data/value associated with that field. The field
+ name is composed of printable ASCII characters (i.e.,
+ characters that have values between 33 and 126, inclusive)
+ except colon and must not with a begin with #. The
+ field ends at the end of the line or at the end of the
+ last continuation line (see below). Horizontal whitespace
(spaces and tabs) may occur immediately before or after the
value and is ignored there; it is conventional to put a
single space after the colon. For example, a field might
</p>
<p>
- Many fields' values may span several lines; in this case
- each continuation line must start with a space or a tab.
- Any trailing spaces or tabs at the end of individual
- lines of a field value are ignored.
+ There are three types of fields:
+ <taglist>
+ <tag>simple</tag>
+ <item>
+ The field, including its value, must be a single line. Folding
+ of the field is not permitted. This is the default field type
+ if the definition of the field does not specify a different
+ type.
+ </item>
+ <tag>folded</tag>
+ <item>
+ The value of a folded field is a logical line that may span
+ several lines. The lines after the first are called
+ continuation lines and must start with a space or a tab.
+ Whitespace, including any newlines, is not significant in the
+ field values of folded fields.<footnote>
+ This folding method is similar to RFC 5322, allowing control
+ files that contain only one paragraph and no multiline fields
+ to be read by parsers written for RFC 5322.
+ </footnote>
+ </item>
+ <tag>multiline</tag>
+ <item>
+ The value of a multiline field may comprise multiple continuation
+ lines. The first line of the value, the part on the same line as
+ the field name, often has special significance or may have to be
+ empty. Other lines are added following the same syntax as the
+ continuation lines of the folded fields. Whitespace, including newlines,
+ is significant in the values of multiline fields.
+ </item>
+ </taglist>
</p>
<p>
- In fields where it is specified that lines may not wrap,
- only a single line of data is allowed and whitespace is not
- significant in a field body. Whitespace must not appear
+ Whitespace must not appear
inside names (of packages, architectures, files or anything
else) or version numbers, or between the characters of
multi-character version relationships.
</p>
+ <p>
+ The presence and purpose of a field, and the syntax of its
+ value may differ between types of control files.
+ </p>
+
<p>
Field names are not case-sensitive, but it is usual to
capitalize the field names using mixed case as shown below.
</p>
<p>
- Blank lines, or lines consisting only of spaces and tabs,
- are not allowed within field values or between fields - that
- would mean a new paragraph.
+ Paragraph separators (empty lines) and lines consisting only of
+ spaces and tabs are not allowed within field values or between
+ fields. Empty lines in field values are usually escaped by
+ representing them by a space followed by a dot.
+ </p>
+
+ <p>
+ Lines starting with # without any preceding whitespace are comments
+ lines that are only permitted in source package control files
+ (<file>debian/control</file>). These comment lines are ignored, even
+ between two continuation lines. They do not end logical lines.
</p>
<p>
<file>.changes</file> file to accompany the upload, and by
<prgn>dpkg-source</prgn> when it creates the
<file>.dsc</file> source control file as part of a source
- archive. Many fields are permitted to span multiple lines in
- <file>debian/control</file> but not in any other control
+ archive. Some fields are folded in <file>debian/control</file>,
+ but not in any other control
file. These tools are responsible for removing the line
breaks from such fields when using fields from
<file>debian/control</file> to generate other control files.
when they generate output control files.
See <ref id="substvars"> for details.
</p>
-
- <p>
- In addition to the control file syntax described <qref
- id="controlsyntax">above</qref>, this file may also contain
- comment lines starting with <tt>#</tt> without any preceding
- whitespace. All such lines are ignored, even in the middle of
- continuation lines for a multiline field, and do not end a
- multiline field.
- </p>
-
</sect>
<sect id="binarycontrolfiles">
</p>
<p>
- The source package control file is generated by
+ The Debian source control file is generated by
<prgn>dpkg-source</prgn> when it builds the source
archive, from other files in the source package,
described above. When unpacking, it is checked against
</p>
<p>
- Any parser that interprets the Uploaders field in
- <file>debian/control</file> must permit it to span multiple
- lines. Line breaks in an Uploaders field that spans multiple
- lines are not significant and the semantics of the field are
- the same as if the line breaks had not been present.
+ The Uploaders field in <file>debian/control</file> can be folded.
</p>
</sect1>
</p>
<p>
- In the source package control file <file>.dsc</file>, this
- field may contain either the architecture
- wildcard <tt>any</tt> or a list of architectures and
- architecture wildcards separated by spaces. If a list is
- given, it may include (or consist solely of) the special
+ In the Debian source control file <file>.dsc</file>, this
+ field contains a list of architectures and architecture
+ wildcards separated by spaces. When the list contains the
+ architecture wildcard <tt>any</tt>, the only other value
+ allowed in the list is <tt>all</tt>.
+ </p>
+
+ <p>
+ The list may include (or consist solely of) the special
value <tt>all</tt>. In other words, in <file>.dsc</file>
files unlike the <file>debian/control</file>, <tt>all</tt> may
occur in combination with specific architectures.
- The <tt>Architecture</tt> field in the source package control
+ The <tt>Architecture</tt> field in the Debian source control
file <file>.dsc</file> is generally constructed from
the <tt>Architecture</tt> fields in
the <file>debian/control</file> in the source package.
</p>
<p>
- Specifying <tt>any</tt> indicates that the source package
+ Specifying only <tt>any</tt> indicates that the source package
isn't dependent on any particular architecture and should
compile fine on any one. The produced binary package(s)
- will either be specific to whatever the current build
- architecture is or will be architecture-independent.
+ will be specific to whatever the current build architecture is.
</p>
<p>
Specifying only <tt>all</tt> indicates that the source package
- will only build architecture-independent packages. If this is
- the case, <tt>all</tt> must be used rather than <tt>any</tt>;
- <tt>any</tt> implies that the source package will build at
- least one architecture-dependent package.
+ will only build architecture-independent packages.
+ </p>
+
+ <p>
+ Specifying <tt>any all</tt> indicates that the source package
+ isn't dependent on any particular architecture. The set of
+ produced binary packages will include at least one
+ architecture-dependant package and one architecture-independent
+ package.
</p>
<p>
<p>
This is a boolean field which may occur only in the
control file of a binary package or in a per-package fields
- paragraph of a main source control data file.
+ paragraph of a source package control file.
</p>
<p>
In a source or binary control file, the <tt>Description</tt>
field contains a description of the binary package, consisting
of two parts, the synopsis or the short description, and the
- long description. The field's format is as follows:
+ long description. It is a multiline field with the following
+ format:
</p>
<p>
Those starting with a single space are part of a paragraph.
Successive lines of this form will be word-wrapped when
displayed. The leading space will usually be stripped off.
+ The line must contain at least one non-whitespace character.
</item>
<item>
will be allowed to trail off to the right. None, one or two
initial spaces may be deleted, but the number of spaces
deleted from each line will be the same (so that you can have
- indenting work correctly, for example).
+ indenting work correctly, for example). The line must
+ contain at least one non-whitespace character.
</item>
<item>
field contains a summary of the descriptions for the packages
being uploaded. For this case, the first line of the field
value (the part on the same line as <tt>Description:</tt>) is
- always empty. The content of the field is expressed as
- continuation lines, one line per package. Each line is
+ always empty. It is a multiline field, with one
+ line per package. Each line is
indented by one space and contains the name of a binary
package, a space, a hyphen (<tt>-</tt>), a space, and the
short description line from that package.
<heading><tt>Changes</tt></heading>
<p>
- This field contains the human-readable changes data, describing
+ This multiline field contains the human-readable changes data, describing
the differences between the last version and the current one.
</p>
<heading><tt>Binary</tt></heading>
<p>
- This field is a list of binary packages. Its syntax and
+ This folded field is a list of binary packages. Its syntax and
meaning varies depending on the control file in which it
appears.
</p>
packages which a source package can produce, separated by
commas<footnote>
A space after each comma is conventional.
- </footnote>. It may span multiple lines. The source package
+ </footnote>. The source package
does not necessarily produce all of these binary packages for
every architecture. The source control file doesn't contain
details of which architectures are appropriate for which of
<p>
When it appears in a <file>.changes</file> file, it lists the
names of the binary packages being uploaded, separated by
- whitespace (not commas). It may span multiple lines.
+ whitespace (not commas).
</p>
</sect1>
and <tt>Checksums-Sha256</tt></heading>
<p>
- These fields contain a list of files with a checksum and size
+ These multiline fields contain a list of files with a checksum and size
for each one. Both <tt>Checksums-Sha1</tt>
and <tt>Checksums-Sha256</tt> have the same syntax and differ
only in the checksum algorithm used: SHA-1
Additional user-defined fields may be added to the
source package control file. Such fields will be
ignored, and not copied to (for example) binary or
- source package control files or upload control files.
+ Debian source control files or upload control files.
</p>
<p>
field name after the hyphen will be used in the output
file. Where the letter <tt>B</tt> is used the field
will appear in binary package control files, where the
- letter <tt>S</tt> is used in source package control
+ letter <tt>S</tt> is used in Debian source control
files and where <tt>C</tt> is used in upload control
(<tt>.changes</tt>) files.
</p>
<example>
XBS-Comment: I stand between the candle and the star.
</example>
- then the binary and source package control files will contain the
+ then the binary and Debian source control files will contain the
field
<example>
Comment: I stand between the candle and the star.
<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>
specification subject to the rules in <ref
id="controlsyntax">, and must appear where it's necessary to
disambiguate; it is not otherwise significant. All of the
- relationship fields may span multiple lines. For
+ relationship fields can only be folded in source package control files. For
consistency and in case of future changes to
<prgn>dpkg</prgn> it is recommended that a single space be
used after a version relationship and before a version
number; it is also conventional to put a single space after
each comma, on either side of each vertical bar, and before
- each open parenthesis. When wrapping a relationship field, it
+ each open parenthesis. When opening a continuation line in a relationship field, it
is conventional to do so after a comma and before the space
following that comma.
</p>
architectures. This is indicated in brackets after each
individual package name and the optional version specification.
The brackets enclose a list of Debian architecture names
+ in the format described in <ref id="arch-spec">,
separated by whitespace. Exclamation marks may be prepended to
each of the names. (It is not permitted for some names to be
prepended with exclamation marks while others aren't.)
<p>
Relationships may also be restricted to a certain set of
- architectures using architecture wildcards. The syntax for
+ architectures using architecture wildcards in the format
+ described in <ref id="arch-wildcard-spec">. The syntax for
declaring such restrictions is the same as declaring
restrictions using a certain set of architectures without
architecture wildcards. For example:
</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>
<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>
For example, the <tt>emacsen-common</tt> package could
contain something like
<example compact="compact">
-if [ ! -e /usr/local/share/emacs ]
-then
- if mkdir /usr/local/share/emacs 2>/dev/null
- then
- chown root:staff /usr/local/share/emacs
- chmod 2775 /usr/local/share/emacs
+if [ ! -e /usr/local/share/emacs ]; then
+ if mkdir /usr/local/share/emacs 2>/dev/null; then
+ if chown root:staff /usr/local/share/emacs; then
+ chmod 2775 /usr/local/share/emacs || true
+ fi
fi
fi
</example>
</p>
</sect>
- <sect>
+ <sect id="cron-jobs">
<heading>Cron jobs</heading>
<p>
Packages must not modify the configuration file
<file>/etc/crontab</file>, and they must not modify the files in
- <file>/var/spool/cron/crontabs</file>.</p>
+ <file>/var/spool/cron/crontabs</file>.
+ </p>
<p>
- If a package wants to install a job that has to be executed
- via cron, it should place a file with the name of the
- package in one or more of the following directories:
+ If a package wants to install a job that has to be executed via
+ cron, it should place a file named as specified
+ in <ref id="cron-files"> into one or more of the following
+ directories:
<example compact="compact">
/etc/cron.hourly
/etc/cron.daily
As these directory names imply, the files within them are
executed on an hourly, daily, weekly, or monthly basis,
respectively. The exact times are listed in
- <file>/etc/crontab</file>.</p>
+ <file>/etc/crontab</file>.
+ </p>
<p>
All files installed in any of these directories must be
<p>
If a certain job has to be executed at some other frequency or
- at a specific time, the package should install a file
- <file>/etc/cron.d/<var>package</var></file>. This file uses the
- same syntax as <file>/etc/crontab</file> and is processed by
- <prgn>cron</prgn> automatically. The file must also be
+ at a specific time, the package should install a file in
+ <file>/etc/cron.d</file> with a name as specified
+ in <ref id="cron-files">. This file uses the same syntax
+ as <file>/etc/crontab</file> and is processed
+ by <prgn>cron</prgn> automatically. The file must also be
treated as a configuration file. (Note that entries in the
<file>/etc/cron.d</file> directory are not handled by
<prgn>anacron</prgn>. Thus, you should only use this
directory for jobs which may be skipped if the system is not
- running.)</p>
+ running.)
+ </p>
+
<p>
Unlike <file>crontab</file> files described in the IEEE Std
1003.1-2008 (POSIX.1) available from
execute scripts in
<file>/etc/cron.{hourly,daily,weekly,monthly}</file>.
</p>
+
+ <sect1 id="cron-files">
+ <p>
+ The file name of a cron job file should normally match the
+ name of the package from which it comes.
+ </p>
+
+ <p>
+ If a package supplies multiple cron job files files in the
+ same directory, the file names should all start with the name
+ of the package (possibly modified as described below) followed
+ by a hyphen (<tt>-</tt>) and a suitable suffix.
+ </p>
+
+ <p>
+ A cron job file name must not include any period or plus
+ characters (<tt>.</tt> or <tt>+</tt>) characters as this will
+ cause cron to ignore the file. Underscores (<tt>_</tt>)
+ should be used instead of <tt>.</tt> and <tt>+</tt>
+ characters.
+ </p>
+ </sect1>
</sect>
<sect id="menus">
package that provides online documentation (other than just
manual pages) to register these documents with
<package>doc-base</package> by installing a
- <package>doc-base</package> control file via the
- <prgn/install-docs/ script at installation time and
- de-register the manuals again when the package is removed.
+ <package>doc-base</package> control file in
+ <file>/usr/share/doc-base/</file>.
</p>
<p>
Please refer to the documentation that comes with the
<heading>Symbolic links</heading>
<p>
- In general, symbolic links within a top-level directory
- should be relative, and symbolic links pointing from one
- top-level directory into another should be absolute. (A
- top-level directory is a sub-directory of the root
- directory <file>/</file>.)
+ In general, symbolic links within a top-level directory should
+ be relative, and symbolic links pointing from one top-level
+ directory to or into another should be absolute. (A top-level
+ directory is a sub-directory of the root
+ directory <file>/</file>.) For example, a symbolic link
+ from <file>/usr/lib/foo</file> to <file>/usr/share/bar</file>
+ should be relative (<file>../share/bar</file>), but a symbolic
+ link from <file>/var/run</file> to <file>/run</file> should be
+ absolute.<footnote>
+ This is necessary to allow top-level directories to be
+ symlinks. If linking <file>/var/run</file>
+ to <file>/run</file> were done with the relative symbolic
+ link <file>../run</file>, but <file>/var</file> were a
+ symbolic link to <file>/srv/disk1</file>, the symbolic link
+ would point to <file>/srv/run</file> rather than the intended
+ target.
+ </footnote>
</p>
<p>
<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>
<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>
policy (such as for <ref id="appdefaults">).
</p>
</sect1>
-
- <sect1>
- <heading>The OSF/Motif and OpenMotif libraries</heading>
-
- <p>
- <em>Programs that require the non-DFSG-compliant OSF/Motif or
- OpenMotif libraries</em><footnote>
- OSF/Motif and OpenMotif are collectively referred to as
- "Motif" in this policy document.
- </footnote>
- should be compiled against and tested with LessTif (a free
- re-implementation of Motif) instead. If the maintainer
- judges that the program or programs do not work
- sufficiently well with LessTif to be distributed and
- supported, but do so when compiled against Motif, then two
- versions of the package should be created; one linked
- statically against Motif and with <tt>-smotif</tt>
- appended to the package name, and one linked dynamically
- against Motif and with <tt>-dmotif</tt> appended to the
- package name.
- </p>
-
- <p>
- Both Motif-linked versions are dependent
- upon non-DFSG-compliant software and thus cannot be
- uploaded to the <em>main</em> distribution; if the
- software is itself DFSG-compliant it may be uploaded to
- the <em>contrib</em> distribution. While known existing
- versions of Motif permit unlimited redistribution of
- binaries linked against the library (whether statically or
- dynamically), it is the package maintainer's
- responsibility to determine whether this is permitted by
- the license of the copy of Motif in their possession.
- </p>
- </sect1>
</sect>
<sect id="perl">
<p>
In addition, the copyright file must say where the upstream
- sources (if any) were obtained. It should name the original
- authors of the package and the Debian maintainer(s) who were
- involved with its creation.
+ sources (if any) were obtained, and should name the original
+ authors.
</p>
<p>
<file>/usr/share/doc/<var>package</var></file> may be a symbolic
link to another directory in <file>/usr/share/doc</file> only if
the two packages both come from the same source and the
- first package Depends on the second. These rules are
- important because copyrights must be extractable by
+ first package Depends on the second. These rules are important
+ because <file>copyright</file> files must be extractable by
mechanical means.
</p>
<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>
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