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8 Debian GNU/Linux Policy Manual.
9 Copyright (C)1996,1997,1998 Ian Jackson and Christian Schwarz;
10 released under the terms of the GNU
11 General Public License, version 2 or (at your option) any later.
12 Initial version 1996, Ian Jackson, ijackson@gnu.ai.mit.edu
13 Revised November 27, 1996, David A. Morris, bweaver@debian.org
14 New sections March 15, 1997, Christian Schwarz, schwarz@debian.org
15 Reworked/Restructured April-July 1997, Christian Schwarz, schwarz@debian.org
16 Maintainer since 1997, Christian Schwarz, schwarz@debian.org
17 Christoph Lameter contributed the "Web Standard"
18 The debian-policy mailing list has taken responsibility for the
19 contents of this document since September 1998, with the package
20 maintainers responsible for packagingn adminstrivia only.
25 <title>Debian Policy Manual</title>
27 <name>Ian Jackson </name>
28 <email>ijackson@gnu.ai.mit.edu</email>
31 <name>Christian Schwarz</name>
32 <email>schwarz@debian.org</email>
35 <name>revised: David A. Morris</name>
36 <email>bweaver@debian.org</email>
39 <name>The Debian Policy mailing List</name>
40 <email>debian-policy@lists.debian.org</email>
42 <version>version &version;, &date;</version>
45 This manual describes the policy requirements for the Debian
46 GNU/Linux distribution. This includes the structure and
47 contents of the Debian archive, several design issues of the
48 operating system, as well as technical requirements that each
49 package must satisfy to be included in the distribution. The
50 policy package itself is maintained by a group of maintainers
51 that have no editorial powers. At the moment, the list of
55 <p>Michael Alan Dorman <email>mdorman@debian.org</email></p>
58 <p>Richard Braakman <email>dark@xs4all.nl</email></p>
61 <p>Philip Hands <email>phil@hands.com</email></p>
64 <p>Manoj Srivastava <email>srivasta@debian.org</email></p>
72 Copyright ©1996,1997,1998 Ian Jackson
73 and Christian Schwarz.
76 This manual is free software; you may redistribute it and/or
77 modify it under the terms of the GNU General Public License
78 as published by the Free Software Foundation; either version
79 2, or (at your option) any later version.
83 This is distributed in the hope that it will be useful, but
84 <em>without any warranty</em>; without even the implied
85 warranty of merchantability or fitness for a particular
86 purpose. See the GNU General Public License for more
90 A copy of the GNU General Public License is available as
91 <tt>/usr/share/common-licences/GPL</tt> in the Debian GNU/Linux
92 distribution or on the World Wide Web at
93 <url id="http://www.gnu.org/copyleft/gpl.html"
94 name="&urlname">. You can also obtain it by writing to the
95 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
96 Boston, MA 02111-1307, USA.
104 <heading>About this manual</heading>
106 <heading>Scope</heading>
108 This manual describes the policy requirements for the Debian
109 GNU/Linux distribution. This includes the structure and
110 contents of the Debian archive, several design issues of the
111 operating system, as well as technical requirements that
112 each package must satisfy to be included in the
116 This manual does <em>not</em> describe the technical
117 mechanisms involved in package creation, installation, and
118 removal. This information can be found in the <em>Debian
119 Packaging Manual</em> and the <em>Debian System
120 Administrators' Manual</em>.
123 This document assumes familiarity with these other two
124 manuals. Unfortunately, the <em>System Administrators'
125 Manual</em> does not exist yet.
128 Much of the information presented in this manual will be
129 useful even when building a package which is to be
130 distributed in some other way or is for local use.
134 <heading>New versions of this document</heading>
136 The current version of this document is always accessible from the
139 id="ftp://ftp.debian.org/debian/doc/manuals/debian-policy.html.tar.gz" name="&urlname">
140 or from the Debian WWW server at
141 <url id="http://www.debian.org/doc/manuals/debian-policy/"
145 In addition, this manual is distributed via the Debian package
146 <tt>debian-policy</tt>
150 <heading>Feedback</heading>
153 As the Debian GNU/Linux system is continuously evolving this
154 manual is changed from time to time.
157 While the authors of this document tried hard not to include
158 any typos or other errors these still occur. If you discover
159 an error in this manual or if you want to tell us any
160 comments, suggestions, or critics please send an email to
161 the Debian Policy List,
162 <email>debian-policy@lists.debian.org</email>, or submit a
163 bug report against the <tt>debian-policy</tt> package.
168 <heading>The Debian Archive</heading>
170 The Debian GNU/Linux system is maintained and distributed as a
171 collection of <em>packages</em>. Since there are so many of them (over
172 2600) they are split into <em>sections</em> and <em>priorities</em> to
173 simplify handling of them.
176 The effort of the Debian project is to build a free operating
177 system, but not every package we want to make accessible is
178 <em>free</em> in our sense (see Debian Free Software
179 Guidelines, below), or may be imported/exported without
180 restrictions. Thus, the archive is split into the sections
181 <em>main</em>, <em>non-us</em>, <em>non-free</em>, and
182 <em>contrib</em>.</p>
184 The <em>main</em> section forms the <em>Debian GNU/Linux
185 distribution</em>. </p>
187 Packages in the other sections are not considered as part of
188 the Debian distribution, though we support their use, and we
189 provide infrastructure for them (such as our bug-tracking
190 system and mailing lists). This Debian Policy Manual applies
191 to these packages as well.</p>
193 <sect id="pkgcopyright">
194 <heading>Package copyright and sections</heading>
196 The aims of this policy are:
198 <list compact="compact">
200 <p>We want to make as much software available as we
204 <p>We want to encourage everyone to write free software.</p>
207 <p> We want to make it easy for people to produce
208 CD-ROMs of our system without violating any licenses,
209 import/export restrictions, or any other laws.</p>
214 <heading>The Debian Free Software Guidelines</heading>
216 The Debian Free Software Guidelines (DFSG) is our
217 definition of `free' software.
219 <tag>Free Redistribution
223 The license of a Debian component may not restrict any
224 party from selling or giving away the software as a
225 component of an aggregate software distribution
226 containing programs from several different
227 sources. The license may not require a royalty or
228 other fee for such sale.
235 The program must include source code, and must allow
236 distribution in source code as well as compiled form.
243 The license must allow modifications and derived
244 works, and must allow them to be distributed under the
245 same terms as the license of the original software.
248 <tag>Integrity of The Author's Source Code
252 The license may restrict source-code from being
253 distributed in modified form <em>only</em> if the
254 license allows the distribution of ``patch files''
255 with the source code for the purpose of modifying the
256 program at build time. The license must explicitly
257 permit distribution of software built from modified
258 source code. The license may require derived works to
259 carry a different name or version number from the
260 original software. (This is a compromise. The Debian
261 group encourages all authors to not restrict any
262 files, source or binary, from being modified.)
265 <tag>No Discrimination Against Persons or Groups
269 The license must not discriminate against any person
273 <tag>No Discrimination Against Fields of Endeavor
277 The license must not restrict anyone from making use
278 of the program in a specific field of endeavor. For
279 example, it may not restrict the program from being
280 used in a business, or from being used for genetic
284 <tag>Distribution of License
288 The rights attached to the program must apply to all
289 to whom the program is redistributed without the need
290 for execution of an additional license by those
294 <tag>License Must Not Be Specific to Debian
298 The rights attached to the program must not depend on
299 the program's being part of a Debian system. If the
300 program is extracted from Debian and used or
301 distributed without Debian but otherwise within the
302 terms of the program's license, all parties to whom
303 the program is redistributed must have the same
304 rights as those that are granted in conjunction with
308 <tag>License Must Not Contaminate Other Software
312 The license must not place restrictions on other
313 software that is distributed along with the licensed
314 software. For example, the license must not insist
315 that all other programs distributed on the same medium
316 must be free software.
319 <tag>Example Licenses
323 The ``GPL,'' ``BSD,'' and ``Artistic'' licenses are
324 examples of licenses that we consider <em>free</em>.
331 <heading>The main section</heading>
333 Every package in "main" must comply with the DFSG (Debian
334 Free Software Guidelines).</p>
337 In addition, the packages in "main"
338 <list compact="compact">
341 must not require a package outside of "main" for
342 compilation or execution (thus, the package may not
343 declare a "Depends" or "Recommends" relationship on a
349 must not be so buggy that we refuse to support them,
354 must meet all policy requirements presented in this
362 <heading>The contrib section</heading>
364 Every package in "contrib" must comply with the DFSG.
368 Examples of packages which would be included in "contrib" are
369 <list compact="compact">
372 free packages which require "contrib", "non-free", or
373 "non-US" packages or packages which are not in our
374 archive at all for compilation or execution,
379 wrapper packages or other sorts of free accessories for
385 packages which we don't want to support because they are too
391 packages which fail to meet some other policy requirements in
399 <heading>The non-free section</heading>
401 `Non-free' contains packages which are not compliant with
402 the DFSG or which are encumbered by patents or other legal
403 issues that make their distribution problematic.</p>
405 All packages in `non-free' must be electronically
406 distributable across international borders.
410 <heading>The non-us server</heading>
412 Some programs with cryptographic program code must be stored
413 on the "non-us" server because of export restrictions of the
416 This applies only to packages which contain cryptographic
417 code. A package containing a program with an interface to a
418 cryptographic program or a program that's dynamically linked
419 against a cryptographic library can be distributed if it is
420 capable of running without the cryptography library or
425 <heading>Further copyright considerations</heading>
427 Every package must be accompanied by a verbatim copy of its
428 copyright and distribution license in the file
429 /usr/share/doc/<package-name>/copyright (see <ref
430 id="copyrightfile"> for details).</p>
432 We reserve the right to restrict files from being included
433 anywhere in our archives if
434 <list compact="compact">
437 their use or distribution would break a law,
442 there is an ethical conflict in their distribution or
448 we would have to sign a license for them, or
453 their distribution would conflict with other project
461 Programs whose authors encourage the user to make donations
462 are fine for the main distribution, provided that the
463 authors do not claim that not donating is immoral,
464 unethical, illegal or something similar; otherwise they must
465 go in contrib (or non-free, if even distribution is
466 restricted by such statements).</p>
469 Packages whose copyright permission notices (or patent
470 problems) do not allow redistribution even of only binaries,
471 and where no special permission has been obtained, cannot be
472 placed on the Debian FTP site and its mirrors at all.</p>
475 Note, that under international copyright law (this applies
476 in the United States, too) <em>no</em> distribution or
477 modification of a work is allowed without an explicit notice
478 saying so. Therefore a program without a copyright notice
479 <em>is</em> copyrighted and you may not do anything to it
480 without risking being sued! Likewise if a program has a
481 copyright notice but no statement saying what is permitted
482 then nothing is permitted.</p>
485 Many authors are unaware of the problems that restrictive
486 copyrights (or lack of copyright notices) can cause for the
487 users of their supposedly-free software. It is often
488 worthwhile contacting such authors diplomatically to ask
489 them to modify their license terms. However, this is a
490 politically difficult thing to do and you should ask for
491 advice on <tt>debian-devel</tt> first.</p>
494 When in doubt, send mail to
495 <email>debian-devel@lists.debian.org</email>. Be prepared
496 to provide us with the copyright statement. Software
497 covered by the GPL, public domain software and BSD-like
498 copyrights are safe; be wary of the phrases `commercial use
499 prohibited' and `distribution restricted'.</p>
502 <heading>Subsections</heading>
505 The packages in the <em>main</em>, <em>contrib</em>, and
506 <em>non-free</em> sections are grouped further into
507 <em>subsections</em> to simplify handling of them.</p>
510 The section for each package is specified in the package's
511 <em>control record</em>. However, the maintainer of the
512 Debian archive may override this selection to assure the
513 consistency of the Debian distribution. </p>
516 Please check the current Debian distribution to see which
517 sections are available.</p>
520 <heading>Priorities</heading>
523 Each package is given a certain <em>priority</em> value,
524 which is included in the package's <em>control
525 record</em>. This information is used in the Debian package
526 management tool to separate high-priority packages from
527 less-important packages.</p>
530 The following <em>priority levels</em> are supported by the
531 Debian package management system, <prgn>dpkg</prgn>.
533 <tag><tt>required</tt></tag>
536 <tt>required</tt> packages are necessary for the
537 proper functioning of the system. You must not remove
538 these packages or your system may become totally
539 broken and you may not even be able to use
540 <prgn>dpkg</prgn> to put things back. Systems with
541 only the <tt>required</tt> packages are probably
542 unusable, but they do have enough functionality to
543 allow the sysadmin to boot and install more
546 <tag><tt>important</tt></tag>
549 Important programs, including those which one would
550 expect to find on any Unix-like system. If the
551 expectation is that an experienced Unix person who
552 found it missing would say `What the F*!@<+ is
553 going on, where is <prgn>foo</prgn>', it must be in
554 <tt>important</tt>. This is an important criterion
555 because we are trying to produce, amongst other
556 things, a free Unix. Other packages without which the
557 system will not run well or be usable must also be
558 here. This does <em>not</em> include Emacs, the X
559 Window System, TeX or any other large applications.
560 The <tt>important</tt> packages are just a bare
561 minimum of commonly-expected and necessary tools.</p>
563 <tag><tt>standard</tt></tag>
566 These packages provide a reasonably small but not too
567 limited character-mode system. This is what will
568 install by default if the user doesn't select anything
569 else. It doesn't include many large applications, but
570 it does include Emacs (this is more of a piece of
571 infrastructure than an application) and a reasonable
572 subset of TeX and LaTeX (if this is possible without
575 <tag><tt>optional</tt></tag>
578 (In a sense everything is optional that isn't
579 required, but that's not what is meant here.) This is
580 all the software that you might reasonably want to
581 install if you didn't know what it was or don't have
582 specialised requirements. This is a much larger system
583 and includes the X Window System, a full TeX
584 distribution, and lots of applications.</p>
586 <tag><tt>extra</tt></tag>
589 This contains packages that conflict with others with
590 higher priorities, or are only likely to be useful if
591 you already know what they are or have specialised
598 Packages may not depend on packages with lower priority
599 values. If this does happen, one of the priority values
600 will have to be adapted.
605 <heading>Binary packages</heading>
608 The Debian GNU/Linux distribution is based on the Debian
609 package management system, called <prgn>dpkg</prgn>. Thus,
610 all packages in the Debian distribution have to be provided
611 in the <tt>.deb</tt> file format.</p>
615 <heading>The package name</heading>
618 Every package must have a name that's unique within the Debian
622 Package names may only consist of lower case letters, digits (0-9),
623 plus (+) or minus (-) signs, and periods (.).</p>
626 The package name is part of the file name of the
627 <tt>.deb</tt> file and is included in the control field
633 <heading>The maintainer of a package</heading>
636 Every package must have exactly one maintainer at a
637 time. This person is responsible that the license of the
638 package's software complies with the policy of the
639 distribution this package is included in.</p>
642 The maintainer must be specified in the
643 <tt>Maintainer</tt> control field with the correct name
644 and a working email address for the Debian maintainer of
645 the package. If one person maintains several packages
646 he/she should try to avoid having different forms of their
647 name and email address in different <tt>Maintainer</tt>
651 If the maintainer of a package quits from the Debian
652 project the Debian QA Group takes over the maintainership
653 of the package until someone else volunteers for that
654 task. These packages are called <em>orphaned
661 <heading>The description of a package</heading>
664 Every Debian package must have an extended description
665 stored in the appropriate field of the control record.</p>
668 The description must be written so that it tells the user
669 what they need to know to decide whether to install the
670 package. This description should not just be copied from
671 the blurb for the program. Instructions for configuring
672 or using the package must not be included -- that is what
673 installation scripts, manual pages, Info files, etc. are
674 for. Copyright statements and other administrivia must
675 not be included -- that is what the copyright file is
681 <heading>Dependencies</heading>
684 Every package has to specify the dependency information
685 about other packages, that are required for the first to
689 For example, for any shared libraries required by
690 dynamically-linked executable binary in a package a
691 dependency entry has to be provided.</p>
694 It is not necessary for other packages to declare any
695 dependencies they have on other packages which are marked
696 <tt>Essential</tt> (see below).</p>
699 Sometimes, a package requires another package to be
700 installed <em>and</em> configured before it can be
701 installed. In this case, you'll have to specify a
702 <tt>Pre-Depends</tt> entry for the package.</p>
705 You must not specify a <tt>Pre-Depends</tt> entry for a
706 package before this has been discussed on the
707 <tt>debian-devel</tt> mailing list and a consensus about
708 doing that has been reached.</p></sect1>
712 <heading>Virtual packages</heading>
715 Sometimes, there are several packages doing more-or-less
716 the same job. In this case, it's useful to define a
717 <em>virtual package</em> who's name describes the function
718 the packages have. (The virtual packages just exist
719 logically, not physically--that's why they are called
720 <em>virtual</em>.) The packages with this particular
721 function will then <em>provide</em> the virtual
722 package. Thus, any other package requiring that function
723 can simply depend on the virtual package without having to
724 specify all possible packages individually.</p>
727 All packages must use virtual package names where
728 appropriate, and arrange to create new ones if necessary.
729 They must not use virtual package names (except privately,
730 amongst a cooperating group of packages) unless they have
731 been agreed upon and appear in the list of virtual package
735 The latest version of the authoritative list of virtual
736 package names can be found on
737 <ftpsite>ftp.debian.org</ftpsite> in
738 <ftppath>/debian/doc/package-developer/virtual-package-names-list.text</ftppath>
739 or your local mirror. In addition, it is included in the
740 <tt>debian-policy</tt> package. The procedure for updating
741 the list is described at the top of the file.</p></sect1>
745 <heading>Base packages</heading>
748 The packages included in the <tt>base</tt> section have a
749 special function. They form a minimum subset of the Debian
750 GNU/Linux system that is installed before everything else
751 on a new system. Thus, only very few packages are allowed
752 to go into the <tt>base</tt> section to keep the required
753 disk usage very small.</p>
756 Most of these packages should have the priority value
757 <tt>required</tt> or at least <tt>important</tt>, and many
758 of them will be tagged <tt>essential</tt> (see below).</p>
761 You must not place any packages into the <tt>base</tt>
762 section before this has been discussed on the
763 <tt>debian-devel</tt> mailing list and a consensus about
764 doing that has been reached.</p></sect1>
768 <heading>Essential packages</heading>
771 Some packages are tagged <tt>essential</tt>. (They have
772 <tt>Essential: yes</tt> in their package control record.)
773 This flag is used for packages that are <em>essential</em>
777 Since these packages can not easily be removed (you'll
778 have to specify an extra <em>force option</em> to
779 <prgn>dpkg</prgn>) this flag must only be used where
780 absolutely necessary.
782 A shared library package must not be tagged
783 <em>essential</em>--the dependencies will prevent its
784 premature removal, and we need to be able to remove it
785 when it has been superseded.</p>
788 You must not tag any packages <tt>essential</tt> before
789 this has been discussed on the <tt>debian-devel</tt>
790 mailing and a consensus about doing that has been
795 <heading>Maintainer scripts</heading>
798 The package installation scripts must avoid producing
799 output which it is unnecessary for the user to see and
800 should rely on <prgn>dpkg</prgn> to stave off boredom on
801 the part of a user installing many packages. This means,
802 amongst other things, using the <tt>--quiet</tt> option on
803 <prgn>install-info</prgn>.</p>
806 Packages should try to minimise the amount of prompting
807 they need to do, and they should ensure that the user will
808 only ever be asked each question once. This means that
809 packages should try to use appropriate shared
810 configuration files (such as <tt>/etc/papersize</tt> and
811 <tt>/etc/news/server</tt>), rather than each prompting for
812 their own list of required pieces of information.</p>
815 It also means that an upgrade should not ask the same
816 questions again, unless the user has used <tt>dpkg
817 --purge</tt> to remove the package's configuration. The
818 answers to configuration questions should be stored in an
819 appropriate place in <tt>/etc</tt> so that the user can
820 modify them, and how this has been done should be
824 If a package has a vitally important piece of information
825 to pass to the user (such as "don't run me as I am, you
826 must edit the following configuration files first or you
827 risk your system emitting badly-formatted messages"), it
828 should display this in the <prgn>postinst</prgn> script
829 and prompt the user to hit return to acknowledge the
830 message. Copyright messages do not count as vitally
831 important (they belong in
832 <tt>/usr/share/doc/<var>package</var>/copyright</tt>); neither
833 do instructions on how to use a program (these should be
834 in on line documentation, where all the users can see
838 Any necessary prompting should almost always be confined
839 to the post-installation script, and should be protected
840 with a conditional so that unnecessary prompting doesn't
841 happen if a package's installation fails and the
842 <prgn>postinst</prgn> is called with
843 <tt>abort-upgrade</tt>, <tt>abort-remove</tt> or
844 <tt>abort-deconfigure</tt>.</p>
847 Errors which occur during the execution of an installation
848 script <em>must</em> be checked and the installation
849 <em>must not</em> continue after an error.</p>
852 Note, that <ref id="scripts">, in general applies to
853 package maintainer scripts, too.</p>
856 Do not use <prgn>dpkg-divert</prgn> on a file belonging to
857 another package without consulting the maintainer of that
861 In order for <prgn>update-alternatives</prgn> to work
862 correctly all the packages which supply an instance of the
863 `shared' command name (or, in general, filename) must use
864 it. You can use <tt>Conflicts</tt> to force the
865 De-installation of other packages supplying it which do not
866 (yet) use <prgn>update-alternatives</prgn>. It may in
867 this case be appropriate to specify a conflict on earlier
868 versions on something--this is an exception to the usual
869 rule that this is not allowed.</p>
873 <heading>Source packages</heading>
876 <heading>Standards conformance</heading>
879 You should specify the most recent version of the
880 packaging standards with which your package complies in
881 the source package's <tt>Standards-Version</tt> field.</p>
884 This value will be used to file bug reports automatically
885 if your package becomes too much out of date.</p>
888 The value corresponds to a version of the Debian manuals,
889 as can be found on the title page or page headers and
890 footers (depending on the format).</p>
893 The version number has four components--major and minor
894 number and major and minor patch level. When the
895 standards change in a way that requires every package to
896 change the major number will be changed. Significant
897 changes that will require work in many packages will be
898 signaled by a change to the minor number. The major patch
899 level will be changed for any change to the meaning of the
900 standards, however small; the minor patch level will be
901 changed when only cosmetic, typographical or other edits
902 which do not change the meaning are made, or changes which
903 do not affect the contents of packages.</p>
906 For package maintainers, only the first 3 digits of the
907 manual version are significant in representing the
908 <em>Standards-Version</em>, and either these 3 digits or
909 the complete 4 digits can be specified--that's up to the
913 In the past, people specified 4 digits in the
914 Standards-Version field, like `2.3.0.0'. Since any
915 `patch-level changes' don't introduce new policy, it
916 was thought it would be better to relax policy and
917 only require that the first 3 digits are specified. (4
918 digits can still be used if someone wants to do so.)
924 You should regularly, and especially if your package has
925 become out of date, check for the newest Policy Manual
926 available and update your package, if necessary. When your
927 package complies with the new standards you may update the
928 <tt>Standards-Version</tt> source package field and
929 release it.</p></sect1>
933 <heading>Changes to the upstream sources</heading>
936 If changes to the source code are made that are generally
937 applicable please try to get them included in the upstream
938 version of the package by supplying the upstream authors
939 with the changes in whatever form they prefer.</p>
942 If you need to configure the package differently for
943 Debian or for Linux, and the upstream source doesn't
944 provide a way to configure it the way you need to, please
945 add such configuration facilities (for example, a new
946 <prgn>autoconf</prgn> test or <tt>#define</tt>) and send
947 the patch to the upstream authors, with the default set to
948 the way they originally had it. You can then easily
949 override the default in your <tt>debian/rules</tt> or
950 wherever is appropriate.</p>
953 Please make sure that the <prgn>configure</prgn> utility
954 detects the correct architecture specification string
955 (refer to <ref id="arch-spec"> for details).</p>
958 If you need to edit a <prgn>Makefile</prgn> where
959 GNU-style <prgn>configure</prgn> scripts are used, you
960 should edit the <tt>.in</tt> files rather than editing the
961 <prgn>Makefile</prgn> directly. This allows the user to
962 reconfigure the package if necessary. You should
963 <em>not</em> configure the package and edit the generated
964 <prgn>Makefile</prgn>! This makes it impossible for
965 someone else to later reconfigure the package.</p></sect1>
969 <heading>Documenting your changes</heading>
972 Document your changes and updates to the source package
973 properly in the <tt>debian/changelog</tt> file.</p>
976 A copy of the file which will be installed in
977 <tt>/usr/share/doc/<var>package</var>/copyright</tt> should be
978 in <tt>debian/copyright</tt>.</p>
981 In non-experimental packages you may only use a format for
982 <tt>debian/changelog</tt> which is supported by the most
983 recent released version of <prgn>dpkg</prgn>. If your
984 format is not supported and there is general support for
985 it you should contact the <prgn>dpkg</prgn> maintainer to
986 have the parser script for your format included in the
987 <prgn>dpkg</prgn> package. (You will need to agree that
988 the parser and its manpage may be distributed under the
989 GNU GPL, just as the rest of <prgn>dpkg</prgn>
994 <heading>Error trapping in makefiles</heading>
997 When <prgn>make</prgn> invokes a command in a makefile
998 (including your package's upstream makefiles and the
999 <tt>debian/rules</tt>) it does so using <tt>sh</tt>. This
1000 means that <tt>sh</tt>'s usual bad error handling
1001 properties apply: if you include a miniature script as one
1002 of the commands in your makefile you'll find that if you
1003 don't do anything about it then errors are not detected
1004 and <prgn>make</prgn> will blithely continue after
1008 Every time you put more than one shell command (this
1009 includes using a loop) in a makefile command you
1010 <em>must</em> make sure that errors are trapped. For
1011 simple compound commands, such as changing directory and
1012 then running a program, using <tt>&&</tt> rather
1013 than semicolon as a command separator is sufficient. For
1014 more complex commands including most loops and
1015 conditionals you must include a separate <tt>set -e</tt>
1016 command at the start of every makefile command that's
1017 actually one of these miniature shell scripts.</p></sect1>
1021 <heading>Obsolete constructs and libraries</heading>
1024 The include file <prgn><varargs.h></prgn> is
1025 provided to support end-users compiling very old software;
1026 the library <tt>libtermcap</tt> is provided to support the
1027 execution of software which has been linked against it
1028 (either old programs or those such as Netscape which are
1029 only available in binary form).</p>
1032 Debian packages should be ported to include
1033 <prgn><stdarg.h></prgn> and <tt>ncurses</tt> when
1038 <chapt><heading>The Operating System</heading>
1042 <heading>File system hierarchy</heading>
1046 <heading>Linux File system Structure</heading>
1049 The location of all installed files and directories must
1050 comply (with some exceptions
1052 <p>In an as yet unreleased version of the standard, the
1053 location of the mail spool and state information
1054 directories has changed; and we proipose to follow the
1055 latter, since that would mean that we do not ahve to
1056 move things around again when the new version of the
1057 FHS comes around). The changes are, amongst others,
1058 s%/var/mail%/var/spool/mail% and
1059 s%/var/state%/var/lib%</p>
1061 ) with the Linux File system Hierarchy Standard
1062 (FHS). The latest version of this document can be found
1063 alongside this manual or on
1064 <ftpsite>tsx-11.mit.edu</ftpsite> in
1065 <ftppath>/pub/linux/docs/linux-standards/fsstnd/</ftppath>.
1066 Specific questions about following the standard may be
1067 asked on <prgn>debian-devel</prgn>, or referred to Daniel
1068 Quinlan, the FHS coordinator, at
1069 <email>quinlan@pathname.com</email>.</p></sect1>
1073 <heading>Site-specific programs</heading>
1076 As mandated by the FHS no package should place any
1077 files in <tt>/usr/local</tt>, either by putting them in
1078 the file system archive to be unpacked by <prgn>dpkg</prgn>
1079 or by manipulating them in their maintainer scripts.</p>
1082 However, the package should create empty directories below
1083 <tt>/usr/local</tt> so that the system administrator knows
1084 where to place site-specific files. These directories
1085 should be removed on package removal if they are
1089 Note, that this applies only to directories <em>below</em>
1090 <tt>/usr/local</tt>, not <em>in</em>
1091 <tt>/usr/local</tt>. The directory <tt>/usr/local</tt>
1092 itself may only contain the sub-directories listed in
1093 FHS, section 4.6. However, you may create directories
1094 below them as you wish. You may not remove any of the
1095 directories listed in 4.6, even if you created them.</p>
1098 Since <tt>/usr/local</tt> may be mounted read-only from a
1099 remote server, these directories have to be created and
1100 removed by the <tt>postinst</tt> and <tt>prerm</tt>
1101 maintainer scripts. These scripts must not fail if either
1102 of these operations fail. (In the future, it will be
1103 possible to tell <prgn>dpkg</prgn> not to unpack files
1104 matching certain patterns, so that the directories can be
1105 included in the <tt>.deb</tt> packages and system
1106 administrators who do not wish these directories in
1107 /usr/local do not need to have them.)</p>
1110 For example, the <prgn>emacs</prgn> package will contain
1112 mkdir -p /usr/local/lib/emacs/site-lisp || true
1114 in the <tt>postinst</tt> script, and
1116 rmdir /usr/local/lib/emacs/site-lisp && \
1117 rmdir /usr/local/lib/emacs || \
1120 in the <tt>prerm</tt> script.</p>
1123 If you do create a directory in <tt>/usr/local</tt> for
1124 local additions to a package, you must ensure that
1125 settings in <tt>/usr/local</tt> take precedence over the
1126 equivalents in <tt>/usr</tt>.</p>
1129 The <tt>/usr/local</tt> directory itself and all the subdirectories
1130 created by the package should have permissions 2775 (group-writable
1131 and set-group-id) and be owned by <tt>root.staff</tt>.</p>
1136 <heading>Users and groups</heading>
1139 The Debian system can be configured to use either plain or
1140 shadow passwords.</p>
1143 Some user ids (UIDs) and group ids (GIDs) are reserved
1144 globally for use by certain packages. Because some packages
1145 need to include files which are owned by these users or
1146 groups, or need the ids compiled into binaries, these ids
1147 must be used on any Debian system only for the purpose for
1148 which they are allocated. This is a serious restriction, and
1149 we should avoid getting in the way of local administration
1150 policies. In particular, many sites allocate users and/or
1151 local system groups starting at 100.</p>
1154 Apart from this we should have dynamically allocated ids,
1155 which should by default be arranged in some sensible
1156 order--but the behaviour should be configurable.</p>
1159 No package except <tt>base-passwd</tt> may modify
1160 <tt>/etc/passwd</tt>, <tt>/etc/shadow</tt>, or
1161 <tt>/etc/group</tt>.</p>
1164 The UID and GID ranges are as follows:
1169 Globally allocated by the Debian project, must be the
1170 same on every Debian system. These ids will appear in
1171 the <tt>passwd</tt> and <tt>group</tt> files of all
1172 Debian systems, new ids in this range being added
1173 automatically as the <tt>base-passwd</tt> package is
1177 Packages which need a single statically allocated uid
1178 or gid should use one of these; their maintainers
1179 should ask the <tt>base-passwd</tt> maintainer for
1186 Dynamically allocated system users and groups.
1187 Packages which need a user or group, but can have this
1188 user or group allocated dynamically and differently on
1189 each system, should use `<tt>adduser --system</tt>' to
1190 create the group and/or user. <prgn>adduser</prgn>
1191 will check for the existence of the user or group, and
1192 if necessary choose an unused id based on the ranged
1193 specified in <tt>adduser.conf</tt>.</p></item>
1196 <tag>1000-29999:</tag>
1199 Dynamically allocated user accounts. By default
1200 <prgn>adduser</prgn> will choose UIDs and GIDs for
1201 user accounts in this range, though
1202 <tt>adduser.conf</tt> may be used to modify this
1206 <tag>30000-59999:</tag>
1208 <p>Reserved.</p></item>
1211 <tag>60000-64999:</tag>
1214 Globally allocated by the Debian project, but only
1215 created on demand. The ids are allocated centrally and
1216 statically, but the actual accounts are only created
1217 on users' systems on demand.</p>
1220 These ids are for packages which are obscure or which
1221 require many statically-allocated ids. These packages
1222 should check for and create the accounts in
1223 <tt>/etc/passwd</tt> or <tt>/etc/group</tt> (using
1224 <prgn>adduser</prgn> if it has this facility) if
1225 necessary. Packages which are likely to require
1226 further allocations should have a `hole' left after
1227 them in the allocation, to give them room to
1231 <tag>65000-65533:</tag>
1233 <p>Reserved.</p></item>
1238 <p>User `<tt>nobody</tt>.'</p></item>
1244 <tt>(uid_t)(-1) == (gid_t)(-1)</tt>. NOT TO BE USED,
1245 because it is the error return sentinel value.</p>
1250 <sect id="sysvinit">
1251 <heading>System run levels</heading>
1255 <heading>Introduction</heading>
1258 The <tt>/etc/init.d</tt> directory contains the scripts
1259 executed by <prgn>init</prgn> at boot time and when init
1260 state (or `runlevel') is changed (see <manref name="init"
1261 section="8">).</p> <p>
1263 These scripts are being referenced by symbolic links in
1264 the <tt>/etc/rc<var>n</var>.d</tt> directories. When
1265 changing runlevels, <prgn>init</prgn> looks in the
1266 directory <tt>/etc/rc<var>n</var>.d</tt> for the scripts
1267 it should execute, where <var>n</var> is the runlevel that
1268 is being changed to, or `S' for the boot-up scripts.</p>
1271 The names of the links all have the form
1272 <tt>S<var>mm/<var>script</var></var></tt> or
1273 <tt>K<var>mm/<var>script</var></var></tt> where
1274 <var>mm</var> is a two-digit number and <var>script</var>
1275 is the name of the script (this should be the same as the
1276 name of the actual script in <tt>/etc/init.d</tt>.
1278 When <prgn>init</prgn> changes runlevel first the targets
1279 of the links whose names starting with a <tt>K</tt> are
1280 executed, each with the single argument <tt>stop</tt>,
1281 followed by the scripts prefixed with an <tt>S</tt>, each
1282 with the single argument <tt>start</tt>. The <tt>K</tt>
1283 links are responsible for killing services and the
1284 <tt>S</tt> link for starting services upon entering the
1288 For example, if we are changing from runlevel 2 to
1289 runlevel 3, init will first execute all of the <tt>K</tt>
1290 prefixed scripts it finds in <tt>/etc/rc3.d</tt>, and then
1291 all of the <tt>S</tt> prefixed scripts. The links
1292 starting with <tt>K</tt> will cause the referred-to file
1293 to be executed with an argument of <tt>stop</tt>, and the
1294 <tt>S</tt> links with an argument of <tt>start</tt>.</p>
1297 The two-digit number <var>mm</var> is used to decide which
1298 order to start and stop things in--low-numbered links have
1299 their scripts run first. For example, the <tt>K20</tt>
1300 scripts will be executed before the <tt>K30</tt> scripts.
1301 This is used when a certain service must be started before
1302 another. For example, the name server <prgn>bind</prgn>
1303 might need to be started before the news server
1304 <prgn>inn</prgn> so that <prgn>inn</prgn> can set up its
1305 access lists. In this case, the script that starts
1306 <prgn>bind</prgn> should have a lower number than the
1307 script that starts <prgn>inn</prgn> so that it runs first:
1316 <heading>Writing the scripts</heading>
1319 Packages can and should place scripts in
1320 <tt>/etc/init.d</tt> to start or stop services at boot
1321 time or during a change of runlevel. These scripts should
1322 be named <tt>/etc/init.d/<var>package</var></tt>, and they
1323 should accept one argument, saying what to do:
1326 <tag><tt>start</tt></tag>
1327 <item><p>start the service,</p></item>
1329 <tag><tt>stop</tt></tag>
1330 <item><p>stop the service,</p></item>
1332 <tag><tt>restart</tt></tag>
1333 <item><p>stop and restart the service,</p></item>
1335 <tag><tt>reload</tt></tag>
1336 <item><p>cause the configuration of the service to be
1337 reloaded without actually stopping and restarting
1338 the service,</p></item>
1340 <tag><tt>force-reload</tt></tag> <item><p>cause the
1341 configuration to be reloaded if the service supports
1342 this, otherwise restart the service.</p></item>
1345 The <tt>start</tt>, <tt>stop</tt>, <tt>restart</tt>, and
1346 <tt>force-reload</tt> options must be supported by all
1347 scripts in <tt>/etc/init.d</tt>, the <tt>reload</tt>
1348 option is optional.</p>
1351 The <tt>init.d</tt> scripts should ensure that they will
1352 behave sensibly if invoked with <tt>start</tt> when the
1353 service is already running, or with <tt>stop</tt> when it
1354 isn't, and that they don't kill unfortunately-named user
1355 processes. The best way to achieve this is usually to use
1356 <prgn>start-stop-daemon</prgn>.</p>
1359 If a service reloads its configuration automatically (as
1360 in the case of <prgn>cron</prgn>, for example), the
1361 <tt>reload</tt> option of the <tt>init.d</tt> script
1362 should behave as if the configuration has been reloaded
1366 These scripts should not fail obscurely when the
1367 configuration files remain but the package has been
1368 removed, as the default in <prgn>dpkg</prgn> is to leave
1369 configuration files on the system after the package has
1370 been removed. Only when it is executed with the
1371 <tt>--purge</tt> option will dpkg remove configuration
1372 files. Therefore, you should include a <tt>test</tt>
1373 statement at the top of the script, like this:
1375 test -f <var>program-executed-later-in-script</var> || exit 0
1376 </example></p></sect1>
1379 <heading>Managing the links</heading>
1382 A program is provided, <prgn>update-rc.d</prgn>, to make
1383 it easier for package maintainers to arrange for the
1384 proper creation and removal of
1385 <tt>/etc/rc<var>n</var>.d</tt> symbolic links from their
1386 <tt>postinst</tt> and <tt>postrm</tt> scripts.</p>
1389 You should use this script to make changes to
1390 <tt>/etc/rc<var>n</var>.d</tt> and <em>never</em> include
1391 any <tt>/etc/rc<var>n</var>.d</tt> symbolic links in the
1395 By default <prgn>update-rc.d</prgn> will start services in
1396 each of the multi-user state runlevels (2, 3, 4, and 5)
1397 and stop them in the halt runlevel (0), the single-user
1398 runlevel (1) and the reboot runlevel (6). The system
1399 administrator will have the opportunity to customize
1400 runlevels by simply adding, moving, or removing the
1401 symbolic links in <tt>/etc/rc<var>n</var>.d</tt>.</p>
1404 To get the default behaviour for your package, put in your
1405 <tt>postinst</tt> script
1407 update-rc.d <var>package</var> defaults >/dev/null
1409 and in your <tt>postrm</tt>
1411 if [ purge = "$1" ]; then
1412 update-rc.d <var>package</var> remove >/dev/null
1417 This will use a default sequence number of 20. If it does
1418 not matter when or in which order the script is run, use
1419 this default. If it does, then you should talk to the
1420 maintainer of the <prgn>sysvinit</prgn> package or post to
1421 <tt>debian-devel</tt>, and they will help you choose a
1425 For more information about using <tt>update-rc.d</tt>,
1426 please consult its manpage <manref name="update-rc.d"
1427 section="8">.</p></sect1>
1431 <heading>Boot-time initialization</heading>
1434 There is another directory, <tt>/etc/rc.boot</tt>, which
1435 contains scripts which are run once per machine boot.
1436 This facility is provided for initialization of hardware
1437 devices, cleaning up of leftover files, and so forth.</p>
1440 For example, the <prgn>kbd</prgn> package provides a
1441 script here for initialising the keyboard layout and
1442 console font and mode.</p>
1445 The files in <tt>/etc/rc.boot</tt> should <em>not</em> be
1446 links into <tt>/etc/init.d</tt>--they should be the
1447 scripts themselves.</p>
1450 <tt>rc.boot</tt> should <em>not</em> be used for starting
1451 general-purpose daemons and similar activities. This
1452 should be done using the <tt>rc<var>n</var>.d</tt> scheme,
1453 above, so that the services can be started and stopped
1454 cleanly when the runlevel changes or the machine is to be
1455 shut down or rebooted.</p></sect1>
1459 <heading>Notes</heading>
1462 <em>Do not</em> include the
1463 <tt>/etc/rc<var>n</var>.d/*</tt> symbolic links in the
1464 <tt>.deb</tt> file system archive! <em>This will cause
1465 problems!</em> You should create them with
1466 <prgn>update-rc.d</prgn>, as above.</p>
1469 <em>Do not</em> include the <tt>/etc/rc<var>n</var>.d/*</tt> symbolic links in
1470 <prgn>dpkg</prgn>'s conffiles list! <em>This will cause
1471 problems!</em> <em>Do</em>,
1472 however, include the <tt>/etc/init.d</tt> scripts in
1473 conffiles. (This is important since we want to give the
1474 local system administrator the chance to adapt the scripts
1475 to the local system--e.g., to disable a service without
1476 De-installing the package, or to specify some special
1477 command line options when starting a service--while making
1478 sure her changes aren't lost during the next package
1479 upgrade.)</p></sect1>
1482 <heading>Example</heading>
1485 The <prgn>bind</prgn> DNS (nameserver) package wants to
1486 make sure that the nameserver is running in multiuser
1487 runlevels, and is properly shut down with the system. It
1488 puts a script in <tt>/etc/init.d</tt>, naming the script
1489 appropriately <tt>bind</tt>. As you can see, the script
1490 interprets the argument <tt>reload</tt> to send the
1491 nameserver a <tt>HUP</tt> signal (causing it to reload its
1492 configuration); this way the user can say
1493 <tt>/etc/init.d/bind reload</tt> to reload the name
1500 # Original version by Robert Leslie
1501 # <rob@mars.org>, edited by iwj and cs
1503 test -x /usr/sbin/named || exit 0
1507 echo -n "Starting domain name service: named"
1508 start-stop-daemon --start --quiet --exec /usr/sbin/named
1512 echo -n "Stopping domain name service: named"
1513 start-stop-daemon --stop --quiet \
1514 --pidfile /var/run/named.pid --exec /usr/sbin/named
1518 echo -n "Restarting domain name service: named"
1519 start-stop-daemon --stop --quiet \
1520 --pidfile /var/run/named.pid --exec /usr/sbin/named
1521 start-stop-daemon --start --verbose --exec /usr/sbin/named
1524 force-reload|reload)
1525 echo -n "Reloading configuration of domain name service: named"
1526 start-stop-daemon --stop --signal 1 --quiet \
1527 --pidfile /var/run/named.pid --exec /usr/sbin/named
1531 echo "Usage: /etc/init.d/bind {start|stop|restart|reload|force-reload}" >&2
1540 Another example on which to base your <tt>/etc/init.d</tt>
1541 scripts is in <tt>/etc/init.d/skeleton</tt>.</p>
1544 If this package is happy with the default setup from
1545 <prgn>update-rc.d</prgn>, namely an ordering number of 20
1546 and having named running in all runlevels, it can say in
1547 its <tt>postinst</tt>:
1549 update-rc.d bind defaults >/dev/null
1551 And in its <tt>postrm</tt>, to remove the links when the
1554 if [ purge = "$1" ]; then
1555 update-rc.d acct remove >/dev/null
1561 <heading>Cron jobs</heading>
1564 Packages may not touch the configuration file
1565 <tt>/etc/crontab</tt>, nor may they modify the files in
1566 <tt>/var/spool/cron/crontabs</tt>.</p>
1569 If a package wants to install a job that has to be executed
1570 via cron, it should place a file with the name if the
1571 package in one of the following directories:
1577 As these directory names say, the files within them are executed on
1578 a daily, weekly, or monthly basis, respectively.</p>
1581 If a certain job has to be executed more frequently than
1582 `daily,' the package should install a file
1583 <tt>/etc/cron.d/<package-name></tt> tagged as
1584 configuration file. This file uses the same syntax as
1585 <tt>/etc/crontab</tt> and is processed by <prgn>cron</prgn>
1586 automatically. (Note, that scripts in the
1587 <tt>/etc/cron.d</tt> directory are not handled by
1588 <prgn>anacron</prgn>. Thus, you should only use this
1589 directory for jobs which may be skipped if the system is not
1593 All files installed in any of these directories have to be
1594 scripts (shell scripts, Perl scripts, etc.) so that they can
1595 easily be modified by the local system administrator. In
1596 addition, they have to be registered as configuration
1600 The scripts in these directories have to check, if all
1601 necessary programs are installed before they try to execute
1602 them. Otherwise, problems will arise when a package was
1603 removed (but not purged), since the configuration files are
1604 kept on the system in this situation.</p></sect>
1608 <heading>Console messages</heading>
1611 This section describes different formats for messages
1612 written to standard output by the <tt>/etc/init.d</tt>
1613 scripts. The intent is to improve the consistency of
1614 Debian's startup and shutdown look and feel.</p>
1617 Please look very careful at the details. We want to get the
1618 messages to look exactly the same way concerning spaces,
1619 punctuation, and case of letters.</p>
1622 Here is a list of overall rules that you should use when you
1623 create output messages. They can be useful if you have a
1624 non-standard message that isn't covered in the sections
1631 Every message should cover one line, start with a
1632 capital letter and end with a period `.'.</p></item>
1637 If you want to express that the computer is working on
1638 something (performing a specific task, not starting or
1639 stopping a program), we use an ``ellipsis'', namely
1640 three dots `...'. Note that we don't insert spaces in
1641 front of or behind the dots. If the task has been
1642 completed we write `done.' and a line feed.</p></item>
1647 Design your messages as if the computer is telling you
1648 what he is doing (let him be polite :-) but don't
1649 mention ``him'' directly. For example, if you think
1652 I'm starting network daemons: nfsd mountd.
1656 Starting network daemons: nfsd mountd.
1657 </example></p></item>
1661 The following formats must be used</p>
1666 <p>when daemons get started.</p>
1669 Use this format if your script starts one or more
1670 daemons. The output should look like this (a single
1671 line, no leading spaces):
1673 Starting <description>: <daemon-1> <daemon-2> <...> <daemon-n>.
1675 The <description> should describe the subsystem
1676 the daemon or set of daemons are part of, while
1677 <daemon-1> up to <daemon-n> denote each
1678 daemon's name (typically the file name of the
1682 For example, the output of /etc/init.d/lpd would look like:
1684 Starting printer spooler: lpd.
1688 This can be achieved by saying
1690 echo -n "Starting printer spooler: lpd"
1691 start-stop-daemon --start --quiet lpd
1694 in the script. If you have more than one daemon to
1695 start, you should do the following:
1697 echo -n "Starting remote file system services:"
1698 echo -n " nfsd"; start-stop-daemon --start --quiet nfsd
1699 echo -n " mountd"; start-stop-daemon --start --quiet mountd
1700 echo -n " ugidd"; start-stop-daemon --start --quiet ugidd
1703 This makes it possible for the user to see what takes
1704 so long and when the final daemon has been
1705 started. Please be careful where to put spaces: In the
1706 example above the system administrator can easily
1707 comment out a line if he don't wants to start a
1708 specific daemon, while the displayed message still
1709 looks good.</p></item>
1713 <p>when something needs to be configured.</p>
1716 If you have to set up different parameters of the
1717 system upon boot up, you can use this format:
1719 Setting <parameter> to `<value>'.
1723 You can use the following echo statement to get the quotes right:
1725 echo "Setting DNS domainname to \`"value"'."
1729 Note that the left quotation mark (`) is different
1730 from the right (').</p></item>
1733 <p>when a daemon is stopped.</p>
1736 When you stop a daemon you should issue a message
1737 similar to the startup message, except that `Starting'
1738 is replaced with `Stopping'.</p>
1741 So stopping the printer daemon will like like this:
1743 Stopping printer spooler: lpd.
1744 </example></p></item>
1747 <p>when something is executed.</p>
1750 There a several examples where you have to run a
1751 program at system startup or shutdown to perform a
1752 specific task. For example, setting the system's clock
1753 via `netdate' or killing all processes when the system
1754 comes down. Your message should like this:
1756 Doing something very useful...done.
1758 You should print the `done.' right after the job has been completed,
1759 so that the user gets informed why he has to wait. You can get this
1762 echo -n "Doing something very useful..."
1766 in your script.</p></item>
1769 <p>when the configuration is reloaded.</p>
1772 When a daemon is forced to reload its configuration
1773 files you should use the following format:
1775 Reloading <daemon's-name> configuration...done.
1776 </example></p></item>
1779 <p>when none of the above rules apply.</p>
1782 If you have to print a message that doesn't fit into
1783 the styles described above, you can use something
1784 appropriate, but please have a look at the overall
1785 rules listed above.</p></item>
1790 <heading>Menus</heading>
1793 Menu entries should follow the current menu policy as
1794 defined in the file <ftpsite>ftp.debian.org</ftpsite> in
1795 <ftppath>/debian/doc/package-developer/menu_policy.txt</ftppath>
1796 or your local mirror.
1800 The Debian <tt>menu</tt> packages provides a unique
1801 interface between packages providing applications and
1802 documents, and <em>menu programs</em> (either X window
1803 managers or text-based menu programs as
1804 <prgn>pdmenu</prgn>).</p>
1807 All packages that provide applications that need not be
1808 passed any special command line arguments for normal
1809 operation should register a menu entry for those
1810 applications, so that users of the <tt>menu</tt> package
1811 will automatically get menu entries in their window
1812 managers, as well in shells like <tt>pdmenu</tt>.</p>
1815 Please refer to the <em>Debian Menu System</em> document
1816 that comes with the <tt>menu</tt> package for information
1817 about how to register your applications and web
1818 documents.</p></sect>
1822 <heading>Keyboard configuration</heading>
1825 To achieve a consistent keyboard configuration (i.e., all
1826 applications interpret a keyboard event the same way) all
1827 programs in the Debian distribution have to be configured to
1828 comply with the following guidelines.</p>
1831 Here is a list that contains certain keys and their interpretation:
1834 <tag><tt><--</tt></tag>
1835 <item><p>delete the character to the left of the cursor</p></item>
1837 <tag><tt>Delete</tt></tag>
1838 <item><p>delete the character to the right of the cursor</p></item>
1840 <tag><tt>Control+H</tt></tag>
1841 <item><p>emacs: the help prefix</p></item>
1844 The interpretation of any keyboard events should be
1845 independent of the terminal that's used (either the console,
1846 X terminal emulators, rlogin/telnet session, etc.).</p>
1849 The following list explains how the different programs
1850 should be set up to achieve this:</p>
1853 <list compact="compact">
1854 <item><p>`<tt><--</tt>' generates KB_Backspace in
1857 <item><p>`<tt>Delete</tt>' generates KB_Delete in X.</p></item>
1861 X translations are set up to make KB_Backspace
1862 generate ASCII DEL, and to make KB_Delete generate
1863 <tt>ESC [ 3 ~</tt> (this is the vt220 escape code for
1864 the `delete character' key). This must be done by
1865 loading the resources using xrdb on all local X
1866 displays, not using the application defaults, so that
1867 the translation resources used correspond to the
1868 xmodmap settings.</p></item>
1872 The Linux console is configured to make
1873 `<tt><--</tt>' generate DEL, and `Delete' generate
1874 <tt>ESC [ 3 ~</tt> (this is the case at the
1878 X applications are configured so that Backspace
1879 deletes left, and Delete deletes right. Motif
1880 applications already work like this.</p></item>
1882 <item><p>stty erase <tt>^?</tt> .</p></item>
1885 The `xterm' terminfo entry should have <tt>ESC [ 3
1886 ~</tt> for kdch1, just like TERM=linux and
1887 TERM=vt220.</p></item>
1890 Emacs is programmed to map KB_Backspace or the `stty
1891 erase' character to delete-backward-char, and
1892 KB_Delete or kdch1 to delete-forward-char, and
1893 <tt>^H</tt> to help as always.</p></item>
1896 Other applications use the `stty erase' character and
1897 kdch1 for the two delete keys, with ASCII DEL being
1898 `delete previous character' and kdch1 being `delete
1899 character under cursor'.</p></item>
1903 This will solve the problem except for:</p>
1906 <list compact="compact">
1908 Some terminals have a <tt><--</tt> key that cannot
1909 be made to produce anything except <tt>^H</tt>. On
1910 these terminals Emacs help will be unavailable on
1911 <tt>^H</tt> (assuming that the `stty erase' character
1912 takes precedence in Emacs, and has been set
1913 correctly). M-x help or F1 (if available) can be used
1917 Some operating systems use <tt>^H</tt> for stty erase.
1918 However, modern telnet versions and all rlogin
1919 versions propagate stty settings, and almost all UNIX
1920 versions honour stty erase. Where the stty settings
1921 are not propagated correctly things can be made to
1922 work by using stty manually.</p></item>
1925 Some systems (including previous Debian versions) use
1926 xmodmap to arrange for both <tt><--</tt> and Delete
1927 to generate KB_Delete). We can change the behaviour
1928 of their X clients via the same X resources that we
1929 use to do it for our own, or have our clients be
1930 configured via their resources when things are the
1931 other way around. On displays configured like this
1932 Delete will not work, but <tt><--</tt>
1936 Some operating systems have different kdch1 settings
1937 in their terminfo for xterm and others. On these
1938 systems the Delete key will not work correctly when
1939 you log in from a system conforming to our policy, but
1940 <tt><--</tt> will.</p></item>
1947 <heading>Environment variables</heading>
1950 No program may depend on environment variables to get
1951 reasonable defaults. (That's because these environment
1952 variables would have to be set in a system-wide
1953 configuration file like /etc/profile, which is not supported
1957 If a program should depend on environment variables for its
1958 configuration, the program has to be changed to fall back to
1959 a reasonable default configuration if these environment
1960 variables are not present. If this cannot be done easily
1961 (e.g., if the source code of a non-free program is not
1962 available), the program should be replaced by a small
1963 `wrapper' shell script which sets the environment variables
1964 and calls the original program.</p>
1967 Here is an example of a wrapper script for this purpose:
1973 exec /usr/lib/foo/foo "$@"
1977 Furthermore, as <tt>/etc/profile</tt> is a configuration
1978 file of the <prgn>bash</prgn> package, no other package may
1979 put any environment variables or other commands into that
1984 <heading>Files</heading>
1988 <heading>Binaries</heading>
1991 It is not allowed that two packages install programs with
1992 different functionality but with the same filenames. (The
1993 case of two programs having the same functionality but
1994 different implementations is handled via `alternatives.')
1995 If this case happens, one of the programs has to be
1996 renamed. The maintainers should report this to the
1997 developers' mailing and try to find a consensus about
1998 which package will have to be renamed. If a consensus can
1999 not be reached, <em>both</em> programs must be
2003 Generally the following compilation parameters should be used:
2006 CFLAGS = -O2 -g -Wall # sane warning options vary between programs
2008 install -s # (or use strip on the files in debian/tmp)
2012 Note that all installed binaries should be stripped,
2013 either by using the <tt>-s</tt> flag to
2014 <prgn>install</prgn>, or by calling <prgn>strip</prgn> on
2015 the binaries after they have been copied into
2016 <tt>debian/tmp</tt> but before the tree is made into a
2020 The <tt>-g</tt> flag is useful on compilation so that you
2021 have available a full set of debugging symbols in your
2022 built source tree, in case anyone should file a bug report
2023 involving (for example) a core dump.</p>
2026 The <tt>-N</tt> flag should not be used. On a.out systems
2027 it may have been useful for some very small binaries, but
2028 for ELF it has no good effect.</p>
2031 It is up to the package maintainer to decide what
2032 compilation options are best for the package. Certain
2033 binaries (such as computationally-intensive programs) may
2034 function better with certain flags (<tt>-O3</tt>, for
2035 example); feel free to use them. Please use good judgment
2036 here. Don't use flags for the sake of it; only use them
2037 if there is good reason to do so. Feel free to override
2038 the upstream author's ideas about which compilation
2039 options are best--they are often inappropriate for our
2040 environment.</p></sect>
2044 <heading>Libraries</heading>
2047 All libraries must have a shared version in the lib
2048 package and a static version in the lib-dev package. The
2049 shared version must be compiled with <tt>-fPIC</tt>, and
2050 the static version must not be. In other words, each
2051 <tt>*.c</tt> file is compiled twice.</p>
2054 You have to specify the gcc option <tt>-D_REENTRANT</tt>
2055 when building a library (either static or shared) to make
2056 the library compatible with LinuxThreads.</p>
2059 Note that all installed shared libraries should be
2062 strip --strip-unneeded <your-lib>
2064 (The option `--strip-unneeded' makes <tt>strip</tt> remove
2065 only the symbols which aren't needed for relocation
2066 processing.) Shared libraries can function perfectly well
2067 when stripped, since the symbols for dynamic linking are
2068 in a separate part of the ELF object file.</p>
2071 Note that under some circumstances it may be useful to
2072 install a shared library unstripped, for example when
2073 building a separate package to support debugging.
2077 An ever increasing number of packages are using libtool to
2078 do their linking. The latest GNU libtools (>= 1.3a) can take
2079 advantage of installed libtool archive files (`*.la'). The
2080 main advantage of libtool's .la files is that it allows
2081 libtool to store and subsequently access metadata with
2082 respect to the libraries it builds. libtool will search for
2083 those files, which contain a lot of useful information about
2084 a library (e.g. dependency libraries for static
2085 linking). Also, they're essential for programs using
2090 Certainly libtool is fully capable of linking against shared
2091 libraries which don't have .la files, but being a mere shell
2092 script it can add considerably to the build time of a
2093 libtool using package if that shellscript has to derive all
2094 this infomation from first principles for each library every
2095 time it is linked. With the advent of libtool-1.4 (and to a
2096 lesser extent libtool-1.3), the .la files will also store
2097 information about inter-library dependencies which cannot
2098 necessarily be derived after the .la file is deleted.
2102 Packages that use libtool to create shared libraries must
2103 include the <em>.la</em> files in the <em>-dev</em>
2104 packages. This is a good idea in general, and espescially
2105 for static linking issues.
2109 Please make sure that you use only released versions of
2110 shared libraries to build your packages; otherwise other
2111 users will not be able to run your binaries
2112 properly. Producing source packages that depend on
2113 unreleased compilers is also usually a bad
2120 <heading>Shared libraries</heading>
2123 Packages involving shared libraries should be split up
2124 into several binary packages.</p>
2127 For a straightforward library which has a development
2128 environment and a runtime kit including just shared
2129 libraries you need to create two packages:
2130 <tt><var>libraryname</var><var>soname</var></tt>
2131 (<var>soname</var> is the shared object name of the shared
2132 library--it's the thing that has to match exactly between
2133 building an executable and running it for the dynamic
2134 linker to be able run the program; usually the
2135 <var>soname</var> is the major number of the library) and
2136 <tt><var>libraryname</var><var>soname</var>-dev</tt>.</p>
2139 If you prefer only to support one development version at a
2140 time you may name the development package
2141 <tt><var>libraryname</var>-dev</tt>; otherwise you may
2142 wish to use <prgn>dpkg</prgn>'s conflicts mechanism to
2143 ensure that the user only installs one development version
2144 at a time (after all, different development versions are
2145 likely to have the same header files in them, causing a
2146 filename clash if both are installed). Typically the
2147 development version will also need an exact version
2148 dependency on the runtime library, to make sure that
2149 compilation and linking happens correctly.</p>
2152 Packages which use the shared library should have a
2153 dependency on the name of the shared library package,
2154 <tt><var>libraryname</var><var>soname</var></tt>. When
2155 the <var>soname</var> changes you can have both versions
2156 of the library installed while moving from the old library
2160 If your package has some run-time support programs which
2161 use the shared library you must <em>not</em> put them in
2162 the shared library package. If you do that then you won't
2163 be able to install several versions of the shared library
2164 without getting filename clashes. Instead, either create
2165 a third package for the runtime binaries (this package
2166 might typically be named
2167 <tt><var>libraryname</var>-runtime</tt>--note the absence
2168 of the <var>soname</var> in the package name) or if the
2169 development package is small include them in there.</p>
2172 If you have several shared libraries built from the same
2173 source tree you can lump them all together into a single
2174 shared library package, provided that you change all their
2175 <var>soname</var>s at once (so that you don't get filename
2176 clashes if you try to install different versions of the
2177 combined shared libraries package).</p>
2180 Follow the directions in the <em>Debian Packaging
2181 Manual</em> for putting the shared library in its package,
2182 and make sure you include a <tt>shlibs</tt> control area
2183 file with details of the dependencies for packages which
2184 use the library.</p>
2187 Shared libraries should <em>not</em> be installed
2188 executable, since <prgn>ld.so</prgn> does not require this
2189 and trying to execute a shared library results in a core
2194 <heading>Scripts</heading>
2197 All command scripts, including the package maintainer
2198 scripts inside the package and used by <prgn>dpkg</prgn>,
2199 should have a <tt>#!</tt> line naming the shell to be used
2200 to interpret them.</p>
2203 In the case of Perl scripts this should be
2204 <tt>#!/usr/bin/perl</tt>.</p>
2207 Shell scripts (<prgn>sh</prgn> and <prgn>bash</prgn>)
2208 should almost certainly start with <tt>set -e</tt> so that
2209 errors are detected. Every script <em>must</em> use
2210 <tt>set -e</tt> or check the exit status of <em>every</em>
2214 The standard shell interpreter `<tt>/bin/sh</tt>' may be a
2215 symbolic link to any POSIX compatible shell. Thus, shell
2216 scripts specifying `<tt>/bin/sh</tt>' as interpreter may
2217 only use POSIX features. If a script requires non-POSIX
2218 features from the shell interpreter, the appropriate shell
2219 has to be specified in the first line of the script (e.g.,
2220 `<tt>#!/bin/bash</tt>') and the package has to depend on
2221 the package providing the shell (unless the shell package
2222 is marked `Essential', e.g., in the case of
2223 <prgn>bash</prgn>).</p>
2226 Restrict your script to POSIX features when possible so
2227 that it may use <tt>/bin/sh</tt> as its interpreter. If
2228 your script works with <prgn>ash</prgn>, it's probably
2229 POSIX compliant, but if you are in doubt, use
2230 <tt>/bin/bash</tt>.</p>
2233 Perl scripts should check for errors when making any
2234 system calls, including <tt>open</tt>, <tt>print</tt>,
2235 <tt>close</tt>, <tt>rename</tt> and <tt>system</tt>.</p>
2238 <prgn>csh</prgn> and <prgn>tcsh</prgn> should be avoided
2239 as scripting languages. See <em>Csh Programming
2240 Considered Harmful</em>, one of the <tt>comp.unix.*</tt>
2241 FAQs. It can be found on
2242 <url id="http://language.perl.com/versus/csh.whynot">, or
2243 <url id="http://www.cpan.org/doc/FMTEYEWTK/versus/csh.whynot">
2244 or even on <ftpsite>ftp.cpan.org</ftpsite>
2245 <ftppath>/pub/perl/CPAN/doc/FMTEYEWTK/versus/csh.whynot</ftppath>.
2246 If an upstream package comes with <prgn>csh</prgn> scripts
2247 then you must make sure that they start with
2248 <tt>#!/bin/csh</tt> and make your package depend on the
2249 <prgn>c-shell</prgn> virtual package.</p>
2252 Any scripts which create files in world-writable
2253 directories (e.g., in <tt>/tmp</tt>) have to use a
2254 mechanism which will fail if a file with the same name
2258 The Debian base distribution provides the
2259 <prgn>tempfile</prgn> and <prgn>mktemp</prgn> utilities
2260 for use by scripts for this purpose.</p></sect>
2264 <heading>Symbolic links</heading>
2267 In general, symbolic links within a toplevel directory
2268 should be relative, and symbolic links pointing from one
2269 toplevel directory into another should be absolute. (A
2270 toplevel directory is a sub-directory of the root
2274 In addition, symbolic links should be specified as short
2275 as possible, i.e., link targets like `foo/../bar' are
2279 Note that when creating a relative link using
2280 <prgn>ln</prgn> it is not necessary for the target of the
2281 link to exist relative to the working directory you're
2282 running <prgn>ln</prgn> from; nor is it necessary to
2283 change directory to the directory where the link is to be
2284 made. Simply include the string that should appear as the
2285 target of the link (this will be a pathname relative to
2286 the directory in which the link resides) as the first
2287 argument to <prgn>ln</prgn>.</p>
2290 For example, in your <prgn>Makefile</prgn> or
2291 <tt>debian/rules</tt>, do things like:
2293 ln -fs gcc $(prefix)/bin/cc
2294 ln -fs gcc debian/tmp/usr/bin/cc
2295 ln -fs ../sbin/sendmail $(prefix)/bin/runq
2296 ln -fs ../sbin/sendmail debian/tmp/usr/bin/runq
2300 A symbolic link pointing to a compressed file should
2301 always have the same file extension as the referenced
2302 file. (For example, if a file `<tt>foo.gz</tt>' is
2303 referenced by a symbolic link, the filename of the link
2304 has to end with `<tt>.gz</tt>' too, as in
2305 `bar.gz.')</p></sect>
2309 <heading>Device files</heading>
2312 No package may include device files in the package file
2316 If a package needs any special device files that are not
2317 included in the base system, it has to call
2318 <prgn>makedev</prgn> in the <tt>postinst</tt> script,
2319 after asking the user for permission to do so.</p>
2322 No package should remove any device files in the
2323 <tt>postrm</tt> or any other script. This is left to the
2324 system administrator.</p>
2327 Debian uses the serial devices
2328 <tt>/dev/tty*</tt>. Programs using the old
2329 <tt>/dev/cu*</tt> devices should be changed to use
2330 <tt>/dev/tty*</tt>.</p></sect>
2334 <heading>Configuration files</heading>
2337 Any configuration files created or used by your package
2338 should reside in <tt>/etc</tt>. If there are several you
2339 should consider creating a subdirectory named after your
2343 It is almost certain that any file in <tt>/etc</tt> that
2344 is in your package's file system archive should be listed
2345 in <prgn>dpkg</prgn>'s <tt>conffiles</tt> control area
2346 file. (See the <em>Debian Packaging
2350 Only packages that are tagged <em>conflicting</em> with
2351 each other may specify the same file as
2352 <tt>conffile</tt>. A package may not modify a
2353 configuration file of another package.</p>
2356 If two or more packages use the same configuration file,
2357 one of these packages has to be defined as <em>owner</em>
2358 of the configuration file, i.e., it has to list the file
2359 as <tt>conffile</tt> and has to provide a program that
2360 modifies the configuration file.</p>
2363 The other packages have to depend on the <em>owner</em>
2364 package and use that program to update the configuration
2368 Sometimes it's appropriate to build a new package, which
2369 just provides the basic <em>infrastructure</em> for the
2370 other packages and which manages the shared configuration
2371 files. (Check out the <prgn>sgml-base</prgn> package as an
2375 Files in <tt>/etc/skel</tt> will automatically be copied
2376 into new user accounts by <prgn>adduser</prgn>. They
2377 should not be referenced there by any program.</p>
2380 Therefore, if a program needs a dotfile to exist in
2381 advance in <tt>$HOME</tt> to work sensibly that dotfile
2382 should be installed in <tt>/etc/skel</tt> (and listed in
2383 conffiles, if it is not generated and modified dynamically
2384 by the package's installation scripts).</p>
2387 However, programs that require dotfiles in order to
2388 operate sensibly (dotfiles that they do not create
2389 themselves automatically, that is) are a bad thing, and
2390 programs should be configured by the Debian default
2391 installation as close to normal as possible.</p>
2394 Therefore, if a program in a Debian package needs to be
2395 configured in some way in order to operate sensibly that
2396 configuration should be done in a site-wide global
2397 configuration file elsewhere in <tt>/etc</tt>. Only if
2398 the program doesn't support a site-wide default
2399 configuration and the package maintainer doesn't have time
2400 to add it should a default per-user file be placed in
2401 <tt>/etc/skel</tt>.</p>
2404 <tt>/etc/skel</tt> should be as empty as we can make it.
2405 This is particularly true because there is no easy
2406 mechanism for ensuring that the appropriate dotfiles are
2407 copied into the accounts of existing users when a package
2411 Ideally the sysadmin should not have to do any
2412 configuration other than that done (semi-)automatically by
2413 the <tt>postinst</tt> script.</p>
2417 <heading>Log files</heading>
2419 The traditional approach to log files has been to set up ad
2420 hoc log rotation schemes using simple shell scripts and
2421 cron. While this approach is highly customizable, it
2422 requires quite a lot of sysadmin work. Even though the
2423 original Debian system helped a little by automatically
2424 installing a system which can be used as a template, this
2425 was deemed not enough.
2429 A better scheme is to use logrotate, a GPL'd program
2430 developed by Red Hat, which centralizes log management. It
2431 has both a config file (<tt>/etc/logrotate.conf</tt>) and a
2432 directory where packages can drop logrotation info
2433 (<tt>/etc/logrotate.d</tt>).
2437 Log files should usually be named
2438 <tt>/var/log/<var>package</var>.log</tt>. If you have many
2439 log files, or need a separate directory for permissions
2440 reasons (<tt>/var/log</tt> is writable only by
2441 <tt>root</tt>), you should usually create a directory named
2442 <tt>/var/log/<var>package</var></tt>.</p>
2445 Make sure that any log files are rotated occasionally so
2446 that they don't grow indefinitely; the best way to do this
2447 is to drop a script into the directory
2448 <tt>/etc/logrotate.d</tt> and use the facilities provided by
2449 logrotate. Here is a good example for a logrotate config
2450 file (for more information see <manref name="logrotate"
2458 /etc/init.d/foo force-reload
2462 Which rotates all files under `/var/log/foo', saves 12
2463 compressed generations, and sends a HUP signal at the end of
2469 Make sure that any log files are removed when the package is
2470 purged (but not when it is only removed), by checking the
2471 argument to the <tt>postrm</tt> script (see the <em>Debian
2472 Packaging Manual</em> for details).</p>
2477 <heading>Permissions and owners</heading>
2480 The rules in this section are guidelines for general use.
2481 If necessary you may deviate from the details below.
2482 However, if you do so you must make sure that what is done
2483 is secure and you must try to be as consistent as possible
2484 with the rest of the system. You should probably also
2485 discuss it on <prgn>debian-devel</prgn> first.</p>
2488 Files should be owned by <tt>root.root</tt>, and made
2489 writable only by the owner and universally readable (and
2490 executable, if appropriate).</p>
2493 Directories should be mode 755 or (for group-writability)
2494 mode 2775. The ownership of the directory should be
2495 consistent with its mode--if a directory is mode 2775, it
2496 should be owned by the group that needs write access to
2500 Setuid and setgid executables should be mode 4755 or 2755
2501 respectively, and owned by the appropriate user or group.
2502 They should not be made unreadable (modes like 4711 or
2503 2711 or even 4111); doing so achieves no extra security,
2504 because anyone can find the binary in the freely available
2505 Debian package--it is merely inconvenient. For the same
2506 reason you should not restrict read or execute permissions
2507 on non-set-id executables.</p>
2510 Some setuid programs need to be restricted to particular
2511 sets of users, using file permissions. In this case they
2512 should be owned by the uid to which they are set-id, and
2513 by the group which should be allowed to execute them.
2514 They should have mode 4754; there is no point in making
2515 them unreadable to those users who must not be allowed to
2519 Do not arrange that the system administrator can only
2520 reconfigure the package to correspond to their local
2521 security policy by changing the permissions on a binary.
2522 Ordinary files installed by <prgn>dpkg</prgn> (as opposed
2523 to conffiles and other similar objects) have their
2524 permissions reset to the distributed permissions when the
2525 package is reinstalled. Instead you should consider (for
2526 example) creating a group for people allowed to use the
2527 program(s) and making any setuid executables executable
2528 only by that group.</p>
2531 If you need to create a new user or group for your package
2532 there are two possibilities. Firstly, you may need to
2533 make some files in the binary package be owned by this
2534 user or group, or you may need to compile the user or
2535 group id (rather than just the name) into the binary
2536 (though this latter should be avoided if possible). In
2537 this case you need a statically allocated id.</p>
2540 You must ask for a user or group id from the base system
2541 maintainer, and must not release the package until you
2542 have been allocated one. Once you have been allocated one
2543 you must make the package depend on a version of the base
2544 system with the id present in <tt>/etc/passwd</tt> or
2545 <tt>/etc/group</tt>, or alternatively arrange for your
2546 package to create the user or group itself with the
2547 correct id (using <tt>adduser</tt>) in its pre- or
2548 post-installation script (the latter is to be preferred if
2549 it is possible).</p>
2552 On the other hand, the program may able to determine the
2553 uid or gid from the group name at runtime, so that a
2554 dynamic id can be used. In this case you must choose an
2555 appropriate user or group name, discussing this on
2556 <prgn>debian-devel</prgn> and checking with the base
2557 system maintainer that it is unique and that they do not
2558 wish you to use a statically allocated id instead. When
2559 this has been checked you must arrange for your package to
2560 create the user or group if necessary using
2561 <prgn>adduser</prgn> in the pre- or post-installation
2562 script (again, the latter is to be preferred if it is
2566 Note that changing the numeric value of an id associated with a name
2567 is very difficult, and involves searching the file system for all
2568 appropriate files. You need to think carefully whether a static or
2569 dynamic id is required, since changing your mind later will cause
2575 <heading>Customized programs</heading>
2577 <sect id="arch-spec">
2578 <heading>Architecture specification strings</heading>
2581 If a program needs to specify an <em>architecture specification
2582 string</em> in some place, the following format has to be used:
2584 <arch>-<os>
2586 where `<arch>' is one of the following: i386, alpha, arm, m68k,
2587 powerpc, sparc and `<os>' is one of: linux, gnu. Use
2588 of <em>gnu</em> in this string is reserved for the GNU/Hurd
2589 operating system. .</p>
2591 Note, that we don't want to use `<arch>-debian-linux'
2592 to apply to the rule `architecture-vendor-os' since this
2593 would make our programs incompatible to other Linux
2594 distributions. Also note, that we don't use
2595 `<arch>-unknown-linux', since the `unknown' does not
2596 look very good.</p></sect>
2600 <heading>Daemons</heading>
2603 The configuration files <tt>/etc/services</tt>,
2604 <tt>/etc/protocols</tt>, and <tt>/etc/rpc</tt> are managed
2605 by the <prgn>netbase</prgn> package and may not be modified
2606 by other packages.</p>
2609 If a package requires a new entry in one of these files, the
2610 maintainer has to get in contact with the
2611 <prgn>netbase</prgn> maintainer, who will add the entries
2612 and release a new version of the <prgn>netbase</prgn>
2616 The configuration file <tt>/etc/inetd.conf</tt> may be
2617 modified by the package's scripts only via the
2618 <prgn>update-inetd</prgn> script or the
2619 <prgn>DebianNet.pm</prgn> Perl module.</p>
2622 If a package wants to install an example entry into
2623 <tt>/etc/inetd.conf</tt>, the entry has to be preceded with
2624 exactly one hash character (#). Such lines are treated as
2625 `commented out by user' by the <prgn>update-inetd</prgn>
2626 script and are not changed or activated during a package
2631 <heading>Using pseudo-ttys and modifying wtmp, utmp and lastlog</heading>
2634 Some programs need to create pseudo-ttys. This should be done
2635 using Unix98 ptys if the C library supports it. The resulting
2636 program must not be installed setuid root, unless that
2637 is required for other functionality.
2641 The files <tt>/var/run/utmp</tt>, <tt>/var/log/wtmp</tt> and
2642 <tt>/var/log/lastlog</tt> must be installed writeable by
2643 group utmp. Programs who need to modify those files must
2644 be installed install setgid utmp.
2649 <heading>Editors and pagers</heading>
2652 Some programs have the ability to launch an editor or pager
2653 program to edit or display a text document. Since there are
2654 lots of different editors and pagers available in the Debian
2655 distribution, the system administrator and each user should
2656 have the possibility to choose his/her preferred editor and
2660 In addition, every program should choose a good default
2661 editor/pager if none is selected by the user or system
2665 Thus, every program that launches an editor or pager has to
2666 use the EDITOR or PAGER environment variables to determine
2667 the editor/pager the user wants to get started. If these
2668 variables are not set, the programs `/usr/bin/editor' and
2669 `/usr/bin/pager' have to be used, respectively.</p>
2672 These two files are managed through `alternatives.' That is,
2673 every package providing an editor or pager has to call the
2674 `update-alternatives' script to register these programs.</p>
2677 If it is very hard to adapt a program to make us of the
2678 EDITOR and PAGER variable, that program should be configured
2679 to use `/usr/bin/sensible-editor' and
2680 `/usr/bin/sensible-pager' as editor or pager program,
2681 respectively. These are two scripts provided in the Debian
2682 base system that check the EDITOR and PAGER variables and
2683 launches the appropriate program or falls back to
2684 `/usr/bin/editor' and `/usr/bin/pager', automatically.</p>
2687 Since the Debian base system already provides an editor and
2688 a pager program, there is no need for a package to depend on
2689 `editor' and `pager', nor is it necessary for a package to
2690 provide such virtual packages.</p></sect>
2693 <sect id="web-appl">
2694 <heading>Web servers and applications</heading>
2697 This section describes the locations and URLs that have to
2698 be used by all web servers and web application in the Debian
2704 <p>Cgi-bin executable files are installed in the
2707 /usr/lib/cgi-bin/<cgi-bin-name>
2709 and can be referred to as
2711 http://localhost/cgi-bin/<cgi-bin-name>
2712 </example></p></item>
2715 <item><p>Access to html documents</p>
2718 Html documents for a package are stored in
2719 /usr/share/doc/<var>package</var> and can be referred to as
2721 http://localhost/doc/<package>/<filename>
2722 </example></p></item>
2725 <item><p>Web Document Root</p>
2728 Web Applications should try to avoid storing files in
2729 the Web Document Root. Instead use the
2730 /usr/share/doc/<package> directory for documents and
2731 register the Web Application via the menu package. If
2732 access to the web-root is unavoidable then use
2736 as the Document Root. This might be just a
2737 symbolic link to the location where the sysadmin has
2738 put the real document root.</p>
2741 </enumlist></p></sect>
2745 <heading>Mail transport agents</heading>
2748 Debian packages which process electronic mail, whether
2749 mail-user-agents (MUAs) or mail-transport-agents (MTAs),
2750 <em>must</em> make sure that they are compatible with the
2751 configuration decisions below. Failure to do this may
2752 result in lost mail, broken <tt>From:</tt> lines, and other
2753 serious brain damage!</p>
2756 The mail spool is <tt>/var/spool/mail</tt> and the interface
2757 to send a mail message is <tt>/usr/sbin/sendmail</tt> (as
2758 per the FHS). The mail spool is part of the base system
2759 and not part of the MTA package.</p>
2762 All Debian MUAs and MTAs have to use the <tt>maillock</tt>
2763 and <tt>mailunlock</tt> functions provided by the
2764 <tt>liblockfile</tt> packages to lock and unlock mail
2765 boxes. These functions implement a NFS-safe locking
2766 mechanism. (It is ok if MUAs and MTAs don't link against
2767 liblockfile but use a <em>compatible</em> mechanism. Please
2768 compare the mechanisms very carefully!)</p>
2771 Mailboxes are generally 660 <tt><var>user</var>.mail</tt>
2772 unless the user has chosen otherwise. A MUA may remove a
2773 mailbox (unless it has nonstandard permissions) in which
2774 case the MTA or another MUA must recreate it if needed.
2775 Mailboxes must be writable by group mail.</p>
2778 The mail spool is 2775 <tt>mail.mail</tt>, and MUAs need to
2779 be setgid mail to do the locking mentioned above (and
2780 obviously need to avoid accessing other users' mailboxes
2781 using this privilege).</p>
2784 <tt>/etc/aliases</tt> is the source file for the system mail
2785 aliases (e.g., postmaster, usenet, etc.)--it is the one
2786 which the sysadmin and <tt>postinst</tt> scripts may edit.
2787 After <tt>/etc/aliases</tt> is edited the program or human
2788 editing it must call <prgn>newaliases</prgn>. All MTA
2789 packages should come with a <prgn>newaliases</prgn> program,
2790 even if it does nothing, but older MTA packages do not do
2791 this so programs should not fail if <prgn>newaliases</prgn>
2792 cannot be found.</p>
2795 The convention of writing <tt>forward to
2796 <var>address</var></tt> in the mailbox itself is not
2797 supported. Use a <tt>.forward</tt> file instead.</p>
2800 The location for the <prgn>rmail</prgn> program used by UUCP
2801 for incoming mail is <tt>/usr/sbin/rmail</tt>, as per the
2802 FHS. Likewise, <prgn>rsmtp</prgn>, for receiving
2803 batch-SMTP-over-UUCP, is in <tt>/usr/sbin/rsmtp</tt> if it
2807 If you need to know what name to use (for example) on
2808 outgoing news and mail messages which are generated locally,
2809 you should use the file <tt>/etc/mailname</tt>. It will
2810 contain the portion after the username and <tt>@</tt> (at)
2811 sign for email addresses of users on the machine (followed
2815 A package should check for the existence of this file. If
2816 it exists it should use it without comment. (An MTA's
2817 prompting configuration script may wish to prompt the user
2818 even if it finds this file exists.) If it does not exist it
2819 should prompt the user for the value and store it in
2820 <tt>/etc/mailname</tt> as well as using it in the package's
2821 configuration. The prompt should make it clear that the
2822 name will not just be used by that package. For example, in
2823 this situation the INN package says:
2825 Please enter the `mail name' of your system. This is the
2826 hostname portion of the address to be shown on outgoing
2827 news and mail messages. The default is
2828 <var>syshostname</var>, your system's host name. Mail
2829 name [`<var>syshostname</var>']:
2831 where <var>syshostname</var> is the output of <tt>hostname
2832 --fqdn</tt>.</p></sect>
2836 <heading>News system configuration</heading>
2839 All the configuration files related to the NNTP (news)
2840 servers and clients should be located under
2841 <tt>/etc/news</tt>.</p>
2844 There are some configuration issues that apply to a number
2845 of news clients and server packages on the machine. These
2849 <tag>/etc/news/organization</tag>
2850 <item><p>A string which shall appear as the
2851 organization header for all messages posted
2852 by NNTP clients on the machine</p></item>
2854 <tag>/etc/news/server</tag>
2855 <item><p>Contains the FQDN of the upstream NNTP
2856 server, or localhost if the local machine is
2857 an NNTP server.</p></item>
2860 Other global files may be added as required for cross-package news
2861 configuration.</p></sect>
2865 <heading>Programs for the X Window system</heading>
2868 Some programs can be configured with or without support for
2869 the X Window System. Typically, binaries produced when
2870 built with X support will need the X shared libraries to
2874 Such programs should be configured <em>with</em> X support,
2875 and should declare a dependency on <tt>xlib6g</tt> (which
2876 contains X shared libraries). Users who wish to use the
2877 program can install just the relatively small
2878 <tt>xfree86-common</tt> and <tt>xlib6g</tt> packages, and do
2879 not need to install the whole of X.
2883 Do not create two versions (one with X support and one
2884 without) of your package.</p>
2887 <em>Application defaults</em> files have to be installed in
2888 the directory <tt>/usr/X11R6/lib/X11/app-defaults/</tt>.
2889 They are considered as part of the program code. Thus, they
2890 should not be modified and should not be tagged as
2891 <em>conffile</em>. If the local system administrator wants
2892 to customise X applications globally, a file with the same
2893 name as that of the package should be placed in the
2894 <tt>/etc/X11/Xresources/</tt> directory instead.
2895 <em>Important:</em> packages that install files into the
2896 <tt>/etc/X11/Xresources/</tt> directory <em>must</em>
2897 declare a conflict with <tt>xbase (<<
2898 3.3.2.3a-2)</tt>; if this is not done it is possible for the
2899 package to destroy a previously-existing
2900 <tt>/etc/X11/Xresources</tt> <em>file</em>.
2904 No package should ever install files into the directories
2905 <tt>/usr/bin/X11/</tt>, <tt>/usr/share/doc/X11/</tt>,
2906 <tt>/usr/include/X11/</tt>, or <tt>/usr/lib/X11/</tt>; these
2907 directories are actually symbolic links, which <tt>dpkg</tt>
2908 does not follow when unpacking a package. Instead, use
2909 <tt>/usr/X11R6/bin/</tt>,
2910 <tt>/usr/share/doc/</tt><var>package/</var> (i.e., place
2911 files with the rest of your package's documentation),
2912 <tt>/usr/X11R6/include/</tt>, and <tt>/usr/X11R6/lib/</tt>.
2913 It is permissible, and even preferable, however, for a
2914 package to refer to the <tt>/usr/{bin,include,lib}/X11/</tt>
2915 directories internally, however; this restriction governs
2916 only the paths used by the package as it is unpacked onto
2921 If you package a program that requires the (non-free)
2922 OSF/Motif library, you should try to determine if the
2923 programs works reasonably well with the free
2924 re-implementation of Motif called LessTif. If so, build the
2925 package using the LessTif libraries; it can then go into the
2926 main section of the package repository and become an
2927 official part of the Debian distribution.
2931 If however, the Motif-based program works insufficiently
2932 well with LessTif, you should instead provide "-smotif" and
2933 "-dmotif" versions (appending these identifiers to the name
2934 of the package), which are statically and dynamically linked
2935 against the Motif libraries, respectively. (All known
2936 versions of OSF/Motif permit redistribution of
2937 statically-linked binaries using the library, but check the
2938 license on your copy of Motif to be sure.) This two-package
2939 approach allows users without Motif to use the package,
2940 whereas users with Motif installed can enjoy the advantages
2941 of the dynamically-linked version (a considerable savings in
2942 disk space usage, download time, etc.). Neither "-smotif"
2943 nor "-dmotif" packages can go into the main section; if the
2944 licensing on the package is compatible with the Debian Free
2945 Software Guidelines, it may go into the contrib section;
2946 otherwise it must go into the non-free section.
2952 <heading>Emacs lisp programs</heading>
2955 Please refer to the `Debian Emacs Policy' (documented in
2956 <tt>debian-emacs-policy.gz</tt> of the
2957 <prgn>emacsen-common</prgn> package) for details of how to
2958 package emacs lisp programs.</p></sect>
2962 <heading>Games</heading>
2965 The permissions on /var/lib/games are 755
2966 <tt>root.root</tt>.</p>
2969 Each game decides on its own security policy.</p>
2972 Games which require protected, privileged access to
2973 high-score files, savegames, etc., must be made
2974 set-<em>group</em>-id (mode 2755) and owned by
2975 <tt>root.games</tt>, and use files and directories with
2976 appropriate permissions (770 <tt>root.games</tt>, for
2977 example). They must <em>not</em> be made
2978 set-<em>user</em>-id, as this causes security problems. (If
2979 an attacker can subvert any set-user-id game they can
2980 overwrite the executable of any other, causing other players
2981 of these games to run a Trojan horse program. With a
2982 set-group-id game the attacker only gets access to less
2983 important game data, and if they can get at the other
2984 players' accounts at all it will take considerably more
2988 Some packages, for example some fortune cookie programs, are
2989 configured by the upstream authors to install with their
2990 data files or other static information made unreadable so
2991 that they can only be accessed through set-id programs
2992 provided. Do not do this in a Debian package: anyone can
2993 download the <tt>.deb</tt> file and read the data from it,
2994 so there is no point making the files unreadable. Not
2995 making the files unreadable also means that you don't have
2996 to make so many programs set-id, which reduces the risk of a
3000 As described in the FHS, binaries of games should be
3001 installed in the directory <tt>/usr/games</tt>. This also
3002 applies to games that use the X Window system. Manual pages
3003 for games (X and non-X games) should be installed in
3004 <tt>/usr/share/man/man6</tt>.</p>
3008 <chapt><heading>Documentation</heading>
3012 <heading>Manual pages</heading>
3015 You must install manual pages in <prgn>nroff</prgn> source
3016 form, in appropriate places under <tt>/usr/share/man</tt>. You
3017 should only use sections 1 to 9 (see the FHS for more
3018 details). You must <em>not</em> install a preformatted `cat
3022 If no manual page is available for a particular program,
3023 utility or function and this is reported as a bug on
3024 debian-bugs, a symbolic link from the requested manual page
3025 to the <manref name="undocumented" section="7"> manual page
3026 should be provided. This symbolic link can be created from
3027 <tt>debian/rules</tt> like this:
3029 ln -s ../man7/undocumented.7.gz \
3030 debian/tmp/usr/share/man/man[1-9]/the_requested_manpage.[1-9].gz
3032 This manpage claims that the lack of a manpage has been
3033 reported as a bug, so you may only do this if it really has
3034 (you can report it yourself, if you like). Do not close the
3035 bug report until a proper manpage is available.</p>
3038 You may forward a complaint about a missing manpage to the
3039 upstream authors, and mark the bug as forwarded in the
3040 Debian bug tracking system. Even though the GNU Project do
3041 not in general consider the lack of a manpage to be a bug,
3042 we do--if they tell you that they don't consider it a bug
3043 you should leave the bug in our bug tracking system open
3047 Manual pages should be installed compressed using <tt>gzip
3051 If one manpage needs to be accessible via several names it
3052 is better to use a symbolic link than the <tt>.so</tt>
3053 feature, but there is no need to fiddle with the relevant
3054 parts of the upstream source to change from <tt>.so</tt> to
3055 symlinks--don't do it unless it's easy. Do not create hard
3056 links in the manual page directories, and do not put
3057 absolute filenames in <tt>.so</tt> directives. The filename
3058 in a <tt>.so</tt> in a manpage should be relative to the
3059 base of the manpage tree (usually
3060 <tt>/usr/share/man</tt>).</p></sect>
3064 <heading>Info documents</heading>
3067 Info documents should be installed in <tt>/usr/share/info</tt>.
3068 They should be compressed with <tt>gzip -9</tt>.</p>
3071 Your package must call <prgn>install-info</prgn> to update the Info
3073 file, in its post-installation script:
3075 install-info --quiet --section Development Development \
3076 /usr/share/info/foobar.info
3080 It is a good idea to specify a section for the location of
3081 your program; this is done with the <tt>--section</tt>
3082 switch. To determine which section to use, you should look
3083 at <tt>/usr/share/info/dir</tt> on your system and choose the most
3084 relevant (or create a new section if none of the current
3085 sections are relevant). Note that the <tt>--section</tt>
3086 flag takes two arguments; the first is a regular expression
3087 to match (case-insensitively) against an existing section,
3088 the second is used when creating a new one.</p>
3091 You must remove the entries in the pre-removal script:
3093 install-info --quiet --remove /usr/share/info/foobar.info
3097 If <prgn>install-info</prgn> cannot find a description entry
3098 in the Info file you will have to supply one. See <manref
3099 name="install-info" section="8"> for details.</p>
3103 <heading>Additional documentation</heading>
3106 Any additional documentation that comes with the package can
3107 be installed at the discretion of the package maintainer.
3108 Text documentation should be installed in a directory
3109 <tt>/usr/share/doc/<var>package</var></tt>, where
3110 <var>package</var> is the name of the package, and
3111 compressed with <tt>gzip -9</tt> unless it is small.</p>
3114 If a package comes with large amounts of documentation which
3115 many users of the package will not require you should create
3116 a separate binary package to contain it, so that it does not
3117 take up disk space on the machines of users who do not need
3118 or want it installed.</p>
3121 It is often a good idea to put text information files
3122 (<tt>README</tt>s, changelogs, and so forth) that come with
3123 the source package in <tt>/usr/share/doc/<var>package</var></tt>
3124 in the binary package. However, you don't need to install
3125 the instructions for building and installing the package, of
3130 <heading>Preferred documentation formats</heading>
3133 The unification of Debian documentation is being carried out
3137 If your package comes with extensive documentation in a
3138 mark up format that can be converted to various other formats
3139 you should if possible ship HTML versions in a binary
3140 package, in the directory
3141 <tt>/usr/share/doc/<var>appropriate package</var></tt> or its
3144 <p>The rationale: The important thing here is that HTML
3145 docs should be available in <em>some</em> package, not
3146 necessarily in the main binary package, though. </p>
3151 Other formats such as PostScript may be provided at your
3155 <sect id="copyrightfile">
3156 <heading>Copyright information</heading>
3159 Every package must be accompanied by a verbatim copy of its
3160 copyright and distribution license in the file
3161 /usr/share/doc/<package-name>/copyright. This file must
3162 neither be compressed nor be a symbolic link.</p>
3165 In addition, the copyright file must say where the upstream
3166 sources (if any) were obtained, and explain briefly what
3167 modifications were made in the Debian version of the package
3168 compared to the upstream one. It must name the original
3169 authors of the package and the Debian maintainer(s) who were
3170 involved with its creation.</p>
3173 /usr/share/doc/<package-name> may be a symbolic link to a
3174 directory in /usr/share/doc only if two packages both come from
3175 the same source and the first package has a "Depends"
3176 relationship on the second. These rules are important
3177 because copyrights must be extractable by mechanical
3181 Packages distributed under the UCB BSD license, the Artistic
3182 license, the GNU GPL, and the GNU LGPL should refer to the
3183 files /usr/share/common-licenses/BSD,
3184 /usr/share/common-licenses/Artistic,
3185 /usr/share/common-licenses/GPL, and
3186 /usr/share/common-licenses/LGPL.
3189 Why "licenses" and not "copyright"? Because
3190 <tt>/usr/doc/copyright</tt> used to contain all the
3191 copyright files, plus the four common licenses GPL,
3192 LGPL, Artistic and BSD. Now individual copyright files
3193 for packages are no longer in a common directory. Once
3194 <tt>/usr/doc/copyright</tt> is almost empty it makes
3195 sense to rename "copyright" to "licenses"
3198 Why "common-licenses" and not "licenses"? Because if I
3199 put just "licenses" I'm sure I will receive a bug report
3200 saying "license foo is not included in the licenses
3201 directory. They are not all the licenses, just a few
3202 common ones. I could use /usr/share/doc/common-licenses
3203 but I think this is too long, and, after all, the GPL
3204 does not "document" anything, it is merely a licence.
3210 Do not use the copyright file as a general <tt>README</tt>
3211 file. If your package has such a file it should be
3212 installed in <tt>/usr/share/doc/<var>package</var>/README</tt> or
3213 <tt>README.Debian</tt> or some other appropriate place.</p>
3217 <heading>Examples</heading>
3220 Any examples (configurations, source files, whatever),
3221 should be installed in a directory
3222 <tt>/usr/share/doc/<var>package</var>/examples</tt>. These files
3223 should not be referenced by any program--they're there for
3224 the benefit of the system administrator and users, as
3225 documentation only.</p>
3228 <sect id="instchangelog">
3229 <heading>Changelog files</heading>
3232 This installed file must contain a copy of the
3233 <tt>debian/changelog</tt> file from your Debian source tree,
3234 and a copy of the upstream changelog file if there is one.
3235 The debian/changelog file should be installed in
3236 <tt>/usr/share/doc/<var>package</var></tt> as
3237 <tt>changelog.Debian.gz</tt>. If the upstream changelog
3238 file is text formatted, it must be accessible as
3239 <tt>/usr/share/doc/<var>package</var>/changelog.gz</tt>. If
3240 the upstream changelog file is HTML formatted, it must be
3242 <tt>/usr/share/doc/<var>package</var>/changelog.html.gz</tt>.
3243 If the upstream changelog files do not already conform to
3244 this naming convention, then this may be achieved by either
3245 renaming the files or adding a symbolic link at the
3246 packaging developer's discretion. </p>
3249 Both should be installed compressed using <tt>gzip -9</tt>,
3250 as they will become large with time even if they start out
3254 If the package has only one changelog which is used both as
3255 the Debian changelog and the upstream one because there is
3256 no separate upstream maintainer then that changelog should
3257 usually be installed as
3258 <tt>/usr/share/doc/<var>package</var>/changelog.gz</tt>; if
3259 there is a separate upstream maintainer, but no upstream
3260 changelog, then the Debian changelog should still be called
3261 <tt>changelog.Debian.gz</tt>.</p>