X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=policy.sgml;h=a7747eca93e3def70e3ea3612d72ff02c3a6a998;hb=cd25316bae42246ae6dc916c3631050b836a9271;hp=57ff06779bf5b2f2bc484bfa72beef062ecfe5ec;hpb=886ef588bd233de4b482cbe1173aefb5a93f77b8;p=debian%2Fdebian-policy.git diff --git a/policy.sgml b/policy.sgml index 57ff067..a7747ec 100644 --- a/policy.sgml +++ b/policy.sgml @@ -2,6 +2,8 @@ %versiondata; + + ]> @@ -800,6 +802,35 @@ in the .deb file format.

+

+ A .deb package contains two sets of files: a set of files + to install on the system when the package is installed, and a set + of files that provide additional metadata about the package or + which are executed when the package is installed or removed. This + second set of files is called control information files. + Among those files are the package maintainer scripts + and control, the binary + package control file that contains the control fields for + the package. Other control information files + include the shlibs + file used to store shared library dependency information + and the conffiles file that lists the package's + configuration files (described in ). +

+ +

+ There is unfortunately a collision of terminology here between + control information files and files in the Debian control file + format. Throughout this document, a control file refers + to a file in the Debian control file format. These files are + documented in . Only files referred to + specifically as control information files are the files + included in the control information file member of + the .deb file format used by binary packages. Most + control information files are not in the Debian control file + format. +

+ The package name @@ -847,36 +878,30 @@

In general, Debian packages should use the same version - numbers as the upstream sources. -

- -

- However, in some cases where the upstream version number is - based on a date (e.g., a development "snapshot" release) the - package management system cannot handle these version - numbers without epochs. For example, dpkg will consider - "96May01" to be greater than "96Dec24". + numbers as the upstream sources. However, upstream version + numbers based on some date formats (sometimes used for + development or "snapshot" releases) will not be ordered + correctly by the package management software. For + example, dpkg will consider "96May01" to be + greater than "96Dec24".

To prevent having to use epochs for every new upstream - version, the date based portion of the version number - should be changed to the following format in such cases: - "19960501", "19961224". It is up to the maintainer whether - they want to bother the upstream maintainer to change - the version numbers upstream, too. + version, the date-based portion of any upstream version number + should be given in a way that sorts correctly: four-digit year + first, followed by a two-digit numeric month, followed by a + two-digit numeric date, possibly with punctuation between the + components.

- Note that other version formats based on dates which are - parsed correctly by the package management system should - not be changed. -

- -

- Native Debian packages (i.e., packages which have been - written especially for Debian) whose version numbers include - dates should always use the "YYYYMMDD" format. + Native Debian packages (i.e., packages which have been written + especially for Debian) whose version numbers include dates + should also follow these rules. If punctuation is desired + between the date components, remember that hyphen (-) + cannot be used in native package versions. Period + (.) is normally a good choice.

@@ -925,9 +950,9 @@ The description of a package

- Every Debian package must have an extended description - stored in the appropriate field of the control record. - The technical information about the format of the + Every Debian package must have a Description control + field which contains a synopsis and extended description of the + package. Technical information about the format of the Description field is in .

@@ -1054,10 +1079,10 @@

- Sometimes, a package requires another package to be unpacked - and configured before it can be unpacked. In this - case, you must specify a Pre-Depends entry for - the package. + Sometimes, unpacking one package requires that another package + be first unpacked and configured. In this case, the + dependent package must specify this dependency in + the Pre-Depends control field.

@@ -1139,7 +1164,7 @@ must be available and usable on the system at all times, even when packages are in an unconfigured (but unpacked) state. Packages are tagged essential for a system using the - Essential control file field. The format of the + Essential control field. The format of the Essential control field is described in .

@@ -1210,9 +1235,11 @@

- You should not use dpkg-divert on a file - belonging to another package without consulting the - maintainer of that package first. + You should not use dpkg-divert on a file belonging + to another package without consulting the maintainer of that + package first. When adding or removing diversions, package + maintainer scripts must provide the --package flag + to dpkg-divert and must not use --local.

@@ -1257,17 +1284,16 @@

Packages which use the Debian Configuration Management - Specification may contain an additional - config script and a templates - file in their control archive - The control.tar.gz inside the .deb. - See . - . - The config script might be run before the - preinst script, and before the package is unpacked - or any of its dependencies or pre-dependencies are satisfied. - Therefore it must work using only the tools present in - essential packages. + Specification may contain the additional control information + files config + and templates. config is an + additional maintainer script used for package configuration, + and templates contains templates used for user + prompting. The config script might be run before + the preinst script and before the package is + unpacked or any of its dependencies or pre-dependencies are + satisfied. Therefore it must work using only the tools + present in essential packages. Debconf or another tool that implements the Debian Configuration Management Specification will also be installed, and any @@ -2192,16 +2218,16 @@ endif Variable substitutions: debian/substvars

- When dpkg-gencontrol, - dpkg-genchanges and dpkg-source - generate control files they perform variable substitutions - on their output just before writing it. Variable + When dpkg-gencontrol + generates binary package control + files (DEBIAN/control), it performs variable + substitutions on its output just before writing it. Variable substitutions have the form ${variable}. The optional file debian/substvars contains variable substitutions to be used; variables can also be set directly from debian/rules using the -V - option to the source packaging commands, and certain - predefined variables are also available. + option to the source packaging commands, and certain predefined + variables are also available.

@@ -2220,12 +2246,12 @@ endif Optional upstream source location: debian/watch

- This is an optional, recommended control file for the - uscan utility which defines how to automatically - scan ftp or http sites for newly available updates of the - package. This is used by and other Debian QA tools - to help with quality control and maintenance of the + This is an optional, recommended configuration file for the + uscan utility which defines how to automatically scan + ftp or http sites for newly available updates of the + package. This is used + by and other Debian QA + tools to help with quality control and maintenance of the distribution as a whole.

@@ -2497,7 +2523,7 @@ Package: libc6 These fields are used by dpkg-gencontrol to generate control files for binary packages (see below), by dpkg-genchanges to generate the - .changes file to accompany the upload, and by + .changes file to accompany the upload, and by dpkg-source when it creates the .dsc source control file as part of a source archive. Many fields are permitted to span multiple lines in @@ -2531,7 +2557,8 @@ Package: libc6

The DEBIAN/control file contains the most vital - (and version-dependent) information about a binary package. + (and version-dependent) information about a binary package. It + consists of a single paragraph.

@@ -2558,10 +2585,9 @@ Package: libc6 Debian source control files -- .dsc

- This file contains a series of fields, identified and - separated just like the fields in the control file of - a binary package. The fields are listed below; their - syntax is described above, in . + This file consists of a single paragraph, possibly surrounded by + a PGP signature. The fields of that paragraph are listed below. + Their syntax is described above, in . Format (mandatory) @@ -2595,12 +2621,19 @@ Package: libc6 Debian changes files -- .changes

- The .changes files are used by the Debian archive maintenance - software to process updates to packages. They contain one - paragraph which contains information from the - debian/control file and other data about the - source package gathered via debian/changelog - and debian/rules. + The .changes files are used by the Debian archive + maintenance software to process updates to packages. They + consist of a single paragraph, possibly surrounded by a PGP + signature. That paragraph contains information from the + debian/control file and other data about the + source package gathered via debian/changelog + and debian/rules. +

+ +

+ .changes files have a format version that is + incremented whenever the documented fields or their meaning + change. This document describes format &changesversion;.

@@ -3259,12 +3292,30 @@ Package: libc6 Format

- This field specifies a format revision for the file. - The most current format described in the Policy Manual - is version 1.5. The syntax of the - format value is the same as that of a package version - number except that no epoch or Debian revision is allowed - - see . + In .changes + files, this field declares the format version of that file. + The syntax of the field value is the same as that of + a package version number except + that no epoch or Debian revision is allowed. The format + described in this document is &changesversion;. +

+ +

+ In .dsc + Debian source control files, this field declares the + format of the source package. The field value is used by + programs acting on a source package to interpret the list of + files in the source package and determine how to unpack it. + The syntax of the field value is a numeric major revision, a + period, a numeric minor revision, and then an optional subtype + after whitespace, which if specified is an alphanumeric word + in parentheses. The subtype is optional in the syntax but may + be mandatory for particular source format revisions. + + The source formats currently supported by the Debian archive + software are 1.0, 3.0 (native), + and 3.0 (quilt). +

@@ -3525,7 +3576,6 @@ Checksums-Sha256: must match the list of files in the Files field.

- @@ -3588,12 +3638,11 @@ Checksums-Sha256:

- These scripts are the files preinst, - postinst, prerm and - postrm in the control area of the package. - They must be proper executable files; if they are scripts - (which is recommended), they must start with the usual - #! convention. They should be readable and + These scripts are the control information + files preinst, postinst, prerm + and postrm. They must be proper executable files; + if they are scripts (which is recommended), they must start with + the usual #! convention. They should be readable and executable by anyone, and must not be world-writable.

@@ -3608,12 +3657,12 @@ Checksums-Sha256: they exit with a zero status if everything went well.

-

- Additionally, packages interacting with users using - debconf in the postinst script should - install a config script in the control area, - see for details. -

+

+ Additionally, packages interacting with users + using debconf in the postinst script + should install a config script as a control + information file. See for details. +

When a package is upgraded a combination of the scripts from @@ -3709,111 +3758,173 @@ Checksums-Sha256:

- - - new-preinst install - - - new-preinst install old-version - - - new-preinst upgrade old-version - - - old-preinst abort-upgrade - new-version - - + What follows is a summary of all the ways in which maintainer + scripts may be called along with what facilities those scripts + may rely on being available at that time. Script names preceded + by new- are the scripts from the new version of a + package being installed, upgraded to, or downgraded to. Script + names preceded by old- are the scripts from the old + version of a package that is being upgraded from or downgraded + from. +

- - - postinst configure - most-recently-configured-version - - - old-postinst abort-upgrade - new-version - - - conflictor's-postinst abort-remove - in-favour package - new-version - + The preinst script may be called in the following + ways: + + new-preinst install + new-preinst install + old-version + new-preinst upgrade + old-version - postinst abort-remove + The package will not yet be unpacked, so + the preinst script cannot rely on any files + included in its package. Only essential packages and + pre-dependencies (Pre-Depends) may be assumed to be + available. Pre-dependencies will be at least unpacked. + They may be only unpacked or "Half-Configured", not + completely configured, but only if a previous version of the + pre-dependency was completely configured and the + pre-dependency had not been removed since then. + + old-preinst abort-upgrade + new-version - deconfigured's-postinst - abort-deconfigure in-favour - failed-install-package version - [removing conflicting-package - version] + Called during error handling of an upgrade that failed after + unpacking the new package because the postrm + upgrade action failed. The unpacked files may be + partly from the new version or partly missing, so the script + cannot not rely on files included in the package. Package + dependencies may not be available. Pre-dependencies will be + at least unpacked following the same rules as above, except + they may be only "Half-Installed" if an upgrade of the + pre-dependency failed. - + +

- - - prerm remove - - - old-prerm upgrade - new-version - - - new-prerm failed-upgrade - old-version - + The postinst script may be called in the following + ways: + + postinst configure + most-recently-configured-version - conflictor's-prerm remove - in-favour package - new-version + The files contained in the package will be unpacked. All + package dependencies will at least be unpacked. If there + are no circular dependencies involved, all package + dependencies will be configured. + + old-postinst abort-upgrade + new-version + conflictor's-postinst abort-remove + in-favour package + new-version + postinst abort-remove + deconfigured's-postinst + abort-deconfigure in-favour + failed-install-package version + [removing conflicting-package + version] - deconfigured's-prerm deconfigure - in-favour package-being-installed - version [removing - conflicting-package - version] + The files contained in the package will be unpacked. All + package dependencies will at least be "Half-Installed" and + will have previously been configured and not removed. + However, dependencies may not be configured or even fully + unpacked in some error situations. + For example, suppose packages foo and bar are installed + with foo depending on bar. If an upgrade of bar were + started and then aborted, and then an attempt to remove + foo failed because its prerm script failed, + foo's postinst abort-remove would be called with + bar only "Half-Installed". + - + +

- - - postrm remove - - - postrm purge - - - old-postrm upgrade - new-version - + The prerm script may be called in the following + ways: + + prerm remove + old-prerm + upgradenew-version + conflictor's-prerm remove + in-favour package + new-version + deconfigured's-prerm deconfigure + in-favour package-being-installed + version [removing + conflicting-package version] - new-postrm failed-upgrade - old-version + The package whose prerm is being called will be + at least "Half-Installed". All package dependencies will at + least be "Half-Installed" and will have previously been + configured and not removed. If there was no error, all + dependencies will at least be unpacked, but these actions + may be called in various error states where dependencies are + only "Half-Installed" due to a partial upgrade. + + new-prerm failed-upgrade + old-version - new-postrm abort-install + Called during error handling when prerm upgrade + fails. The new package will not yet be unpacked, and all + the same constraints as for preinst upgrade apply. + +

+ +

+ The postrm script may be called in the following + ways: + + postrm remove + postrm purge + old-postrm upgrade + new-version + disappearer's-postrm disappear + overwriter overwriter-version - new-postrm abort-install - old-version + The postrm script is called after the package's + files have been removed or replaced. The package + whose postrm is being called may have + previously been deconfigured and only be unpacked, at which + point subsequent package changes do not consider its + dependencies. Therefore, all postrm actions + may only rely on essential packages and cannot assume that + the package's dependencies are available. + + new-postrm failed-upgrade + old-version - new-postrm abort-upgrade - old-version + Called when the old postrm upgrade action fails. + The new package will be unpacked, but only essential + packages and pre-dependencies can be relied on. + Pre-dependencies will either be configured or will be + "Unpacked" or "Half-Configured" but previously had been + configured and was never removed. + + new-postrm abort-install + new-postrm abort-install + old-version + new-postrm abort-upgrade + old-version - disappearer's-postrm disappear - overwriter - overwriter-version + Called before unpackaging the new package as part of the + error handling of preinst failures. May assume + the same state as preinst can assume. - +

- + Details of unpack phase of installation or upgrade @@ -4289,7 +4400,7 @@ Checksums-Sha256: In the Depends, Recommends, Suggests, Pre-Depends, Build-Depends and Build-Depends-Indep - control file fields of the package, which declare + control fields of the package, which declare dependencies on other packages, the package names listed may also include lists of alternative package names, separated by vertical bar (pipe) symbols |. In such a case, @@ -4343,21 +4454,24 @@ Depends: libc6 (>= 2.2.1), exim | mail-transport-agent

- All fields that specify build-time relationships + Relationships may be restricted to a certain set of + architectures. This is indicated in brackets after each + individual package name and the optional version specification. + The brackets enclose a list of Debian architecture names + separated by whitespace. Exclamation marks may be prepended to + each of the names. (It is not permitted for some names to be + prepended with exclamation marks while others aren't.) +

+ +

+ For build relationship fields (Build-Depends, Build-Depends-Indep, - Build-Conflicts and Build-Conflicts-Indep) - may be restricted to a certain set of architectures. This - is indicated in brackets after each individual package name and - the optional version specification. The brackets enclose a - list of Debian architecture names separated by whitespace. - Exclamation marks may be prepended to each of the names. - (It is not permitted for some names to be prepended with - exclamation marks while others aren't.) If the current Debian - host architecture is not in this list and there are no - exclamation marks in the list, or it is in the list with a - prepended exclamation mark, the package name and the - associated version specification are ignored completely for - the purposes of defining the relationships. + Build-Conflicts and Build-Conflicts-Indep), if + the current Debian host architecture is not in this list and + there are no exclamation marks in the list, or it is in the list + with a prepended exclamation mark, the package name and the + associated version specification are ignored completely for the + purposes of defining the relationships.

@@ -4373,6 +4487,29 @@ Build-Depends: kernel-headers-2.2.10 [!hurd-i386], gnumach-dev only on hurd-i386.

+

+ For binary relationship fields, the architecture restriction + syntax is only supported in the source package control + file debian/control. When the corresponding binary + package control file is generated, the relationship will either + be omitted or included without the architecture restriction + based on the architecture of the binary package. This means + that architecture restrictions must not be used in binary + relationship fields for architecture-independent packages + (Architecture: all). +

+ +

+ For example: + +Depends: foo [i386], bar [amd64] + + becomes Depends: foo when the package is built on + the i386 architecture, Depends: bar when the + package is built on the amd64 architecture, and omitted + entirely in binary packages built on all other architectures. +

+

If the architecture-restricted dependency is part of a set of alternatives using |, that alternative is ignored @@ -4387,11 +4524,11 @@ Build-Depends: foo [!i386] | bar [!amd64]

- All fields that specify build-time relationships may also be - restricted to a certain set of architectures using architecture - wildcards. The syntax for declaring such restrictions is the - same as declaring restrictions using a certain set of - architectures without architecture wildcards. For example: + Relationships may also be restricted to a certain set of + architectures using architecture wildcards. The syntax for + declaring such restrictions is the same as declaring + restrictions using a certain set of architectures without + architecture wildcards. For example: Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any] @@ -4427,7 +4564,7 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any]

This is done using the Depends, Pre-Depends, Recommends, Suggests, Enhances, - Breaks and Conflicts control file fields. + Breaks and Conflicts control fields. Breaks is described in , and Conflicts is described in . The rest are described below. @@ -4465,11 +4602,13 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any]

- Since Depends only places requirements on the - configuration step, packages in an installation run are usually - all unpacked first and all configured later. This makes it - easier to satisfy all dependencies when multiple packages are - being upgraded. + Since Depends only places requirements on the order in + which packages are configured, packages in an installation run + are usually all unpacked first and all configured later. This + allows multiple packages to be upgraded in one unpack and + configure step even if some packages being upgraded have + versioned dependencies on the upgraded versions of other + packages involved in the installation run.

@@ -4479,16 +4618,15 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any] broken at some point and the dependency requirements violated for at least one package. Packages involved in circular dependencies may not be able to rely on their dependencies being - configured when being configured or removed depending on which - side of the break of the circular dependency loop they happen to - be on. If one of the packages in the loop has no - postinst script, then the cycle will be broken at - that package; this ensures that all postinst - scripts are run with their dependencies properly configured if - this is possible. Otherwise the breaking point is arbitrary. - Packages should therefore avoid circular dependencies where - possible, particularly if they have postinst - scripts. + configured when being configured depending on which side of the + break of the circular dependency loop they happen to be on. If + one of the packages in the loop has no postinst + script, then the cycle will be broken at that package; this + ensures that all postinst scripts are run with + their dependencies properly configured if this is possible. + Otherwise the breaking point is arbitrary. Packages should + therefore avoid circular dependencies where possible, + particularly if they have postinst scripts.

@@ -4513,19 +4651,17 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any]

The Depends field should also be used if the - postinst, prerm or - postrm scripts require the package to be - present in order to run. (If both packages are involved - in a dependency loop, this might not work as expected; see - the explanation a few paragraphs back.) In the case of - postinst and postrm, the - depended-on packages will be unpacked and configured - first. (Note, however, that the postrm - cannot rely on any non-essential packages to be present - during the purge phase.) In the case of - prerm, the depended-on package will at least - be unpacked (it might be configured too, but you can't - rely on this unless you use Pre-Depends). + postinst or prerm scripts + require the depended-on package to be unpacked or + configured in order to run. In the case of postinst + configure, the depended-on packages will be unpacked + and configured first. (If both packages are involved in a + dependency loop, this might not work as expected; see the + explanation a few paragraphs back.) In the case + of prerm or other postinst + actions, the package dependencies will be at least + unpacked or "Half-Installed". +

Recommends @@ -4584,11 +4720,11 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any]

- When the package declaring a pre-dependency is about - to be configured, the pre-dependency will be - treated as a normal Depends, that is, it will - be considered satisfied only if the depended-on - package has been correctly configured. However, unlike + When the package declaring a pre-dependency is about to + be configured, the pre-dependency will be treated + as a normal Depends. It will be considered + satisfied only if the depended-on package has been + correctly configured. However, unlike with Depends, Pre-Depends does not permit circular dependencies to be broken. If a circular dependency is encountered while attempting to honor @@ -4682,13 +4818,13 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any] Conflicting binary packages - Conflicts

- When one binary package declares a conflict with another - using a Conflicts field, dpkg will - refuse to allow them to be unpacked on the system at the - same time. This is a stronger restriction than Breaks, - which just prevents both packages from being configured at the - same time. Conflicting packages cannot be unpacked on the - system at the same time. + When one binary package declares a conflict with another using + a Conflicts field, dpkg will refuse to + allow them to be unpacked on the system at the same time. This + is a stronger restriction than Breaks, which only + prevents both packages from being configured at the same time. + Conflicting packages cannot be unpacked on the system at the + same time.

@@ -4757,6 +4893,15 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any] example, .

+

+ Neither Breaks nor Conflicts should be used + unless two packages cannot be installed at the same time or + installing them both causes one of them to be broken or + unusable. Having similar functionality or performing the same + tasks as another package is not sufficient reason to + declare Breaks or Conflicts with that package. +

+

A Conflicts entry may have an "earlier than" version clause if the reason for the conflict is corrected in a later @@ -4786,11 +4931,10 @@ Build-Depends: foo [linux-any], bar [any-i386], baz [!linux-any]

A virtual package is one which appears in the - Provides control file field of another package. - The effect is as if the package(s) which provide a - particular virtual package name had been listed by name - everywhere the virtual package name appears. (See also ) + Provides control field of another package. The effect + is as if the package(s) which provide a particular virtual + package name had been listed by name everywhere the virtual + package name appears. (See also )

@@ -4858,9 +5002,9 @@ Provides: bar

Packages can declare in their control file that they should - overwrite files in certain other packages, or completely - replace other packages. The Replaces control file - field has these two distinct purposes. + overwrite files in certain other packages, or completely replace + other packages. The Replaces control field has these + two distinct purposes.

Overwriting files in other packages @@ -4987,7 +5131,7 @@ Replaces: mail-transport-agent

This is done using the Build-Depends, Build-Depends-Indep, Build-Conflicts and - Build-Conflicts-Indep control file fields. + Build-Conflicts-Indep control fields.

@@ -5002,7 +5146,7 @@ Replaces: mail-transport-agent

There is no Build-Depends-Arch; this role is essentially met with Build-Depends. Anyone building the - build-indep and binary-indep targets is + build-indep and binary-indep targets is assumed to be building the whole package, and therefore installation of all build dependencies is required.

@@ -5051,55 +5195,134 @@ Replaces: mail-transport-agent

- Packages involving shared libraries should be split up into - several binary packages. This section mostly deals with how - this separation is to be accomplished; rules for files within - the shared library packages are in instead. + This section deals only with public shared libraries: shared + libraries that are placed in directories searched by the dynamic + linker by default or which are intended to be linked against + normally and possibly used by other, independent packages. Shared + libraries that are internal to a particular package or that are + only loaded as dynamic modules are not covered by this section and + are not subject to its requirements.

- - Run-time shared libraries +

+ A shared library is identified by the SONAME attribute + stored in its dynamic section. When a binary is linked against a + shared library, the SONAME of the shared library is + recorded in the binary's NEEDED section so that the + dynamic linker knows that library must be loaded at runtime. The + shared library file's full name (which usually contains additional + version information not needed in the SONAME) is + therefore normally not referenced directly. Instead, the shared + library is loaded by its SONAME, which exists on the file + system as a symlink pointing to the full name of the shared + library. This symlink must be provided by the + package. describes how to do this. + + This is a convention of shared library versioning, but not a + requirement. Some libraries use the SONAME as the full + library file name instead and therefore do not need a symlink. + Most, however, encode additional information about + backwards-compatible revisions as a minor version number in the + file name. The SONAME itself only changes when + binaries linked with the earlier version of the shared library + may no longer work, but the filename may change with each + release of the library. See for + more information. + +

- The run-time shared library needs to be placed in a package - whose name changes whenever the shared object version - changes. -

- Since it is common place to install several versions of a - package that just provides shared libraries, it is a - good idea that the library package should not - contain any extraneous non-versioned files, unless they - happen to be in versioned directories.

- - The most common mechanism is to place it in a package - called - librarynamesoversion, - where soversion is the version number - in the soname of the shared library - The soname is the shared object name: it's the thing - that has to match exactly between building an executable - and running it for the dynamic linker to be able run the - program. For example, if the soname of the library is - libfoo.so.6, the library package would be - called libfoo6. - . - Alternatively, if it would be confusing to directly append - soversion to libraryname (e.g. because - libraryname itself ends in a number), you may use - libraryname-soversion and - libraryname-soversion-dev - instead. + When linking a binary or another shared library against a shared + library, the SONAME for that shared library is not yet + known. Instead, the shared library is found by looking for a file + matching the library name with .so appended. This file + exists on the file system as a symlink pointing to the shared + library. +

+ +

+ Shared libraries are normally split into several binary packages. + The SONAME symlink is installed by the runtime shared + library package, and the bare .so symlink is installed in + the development package since it's only used when linking binaries + or shared libraries. However, there are some exceptions for + unusual shared libraries or for shared libraries that are also + loaded as dynamic modules by other programs.

- If you have several shared libraries built from the same - source tree you may lump them all together into a single - shared library package, provided that you change all of - their sonames at once (so that you don't get filename - clashes if you try to install different versions of the - combined shared libraries package). + This section is primarily concerned with how the separation of + shared libraries into multiple packages should be done and how + dependencies on and between shared library binary packages are + managed in Debian. should be read in + conjunction with this section and contains additional rules for + the files contained in the shared library packages.

+ + Run-time shared libraries + +

+ The run-time shared library must be placed in a package + whose name changes whenever the SONAME of the shared + library changes. This allows several versions of the shared + library to be installed at the same time, allowing installation + of the new version of the shared library without immediately + breaking binaries that depend on the old version. Normally, the + run-time shared library and its SONAME symlink should + be placed in a package named + librarynamesoversion, + where soversion is the version number in + the SONAME of the shared library. + See for detailed information on how to + determine this version. Alternatively, if it would be confusing + to directly append soversion + to libraryname (if, for example, libraryname + itself ends in a number), you should use + libraryname-soversion + instead. +

+ +

+ If you have several shared libraries built from the same source + tree, you may lump them all together into a single shared + library package provided that all of their SONAMEs will + always change together. Be aware that this is not normally the + case, and if the SONAMEs do not change together, + upgrading such a merged shared library package will be + unnecessarily difficult because of file conflicts with the old + version of the package. When in doubt, always split shared + library packages so that each binary package installs a single + shared library. +

+ +

+ Every time the shared library ABI changes in a way that may + break binaries linked against older versions of the shared + library, the SONAME of the library and the + corresponding name for the binary package containing the runtime + shared library should change. Normally, this means + the SONAME should change any time an interface is + removed from the shared library or the signature of an interface + (the number of parameters or the types of parameters that it + takes, for example) is changed. This practice is vital to + allowing clean upgrades from older versions of the package and + clean transitions between the old ABI and new ABI without having + to upgrade every affected package simultaneously. +

+ +

+ The SONAME and binary package name need not, and indeed + normally should not, change if new interfaces are added but none + are removed or changed, since this will not break binaries + linked against the old shared library. Correct versioning of + dependencies on the newer shared library by binaries that use + the new interfaces is handled via + the shlibs + system or via symbols files (see + ). +

+

The package should install the shared libraries under their normal names. For example, the libgdbm3 @@ -5119,10 +5342,11 @@ Replaces: mail-transport-agent

- The run-time library package should include the symbolic link that - ldconfig would create for the shared libraries. - For example, the libgdbm3 package should include - a symbolic link from /usr/lib/libgdbm.so.3 to + The run-time library package should include the symbolic link for + the SONAME that ldconfig would create for + the shared libraries. For example, + the libgdbm3 package should include a symbolic + link from /usr/lib/libgdbm.so.3 to libgdbm.so.3.0.0. This is needed so that the dynamic linker (for example ld.so or ld-linux.so.*) can find the library between the @@ -5342,6 +5566,14 @@ Replaces: mail-transport-agent (ld) when compiling packages, as it will only look for libgdbm.so when compiling dynamically.

+ +

+ If the package provides Ada Library Information + (*.ali) files for use with GNAT, these files must be + installed read-only (mode 0444) so that GNAT will not attempt to + recompile them. This overrides the normal file mode requirements + given in . +

@@ -5380,59 +5612,49 @@ Replaces: mail-transport-agent

- Thus, when a package is built which contains any shared - libraries, it must provide a shlibs file for other - packages to use, and when a package is built which contains - any shared libraries or compiled binaries, it must run + When a package is built which contains any shared libraries, it + must provide a shlibs file for other packages to + use. When a package is built which contains any shared + libraries or compiled binaries, it must run dpkg-shlibdeps on these to determine the libraries used and hence the dependencies needed by this package.

- In the past, the shared libraries linked to were - determined by calling ldd, but now - objdump is used to do this. The only - change this makes to package building is that - dpkg-shlibdeps must also be run on shared - libraries, whereas in the past this was unnecessary. - The rest of this footnote explains the advantage that - this method gives. + dpkg-shlibdeps will use a program + like objdump or readelf to find + the libraries directly needed by the binaries or shared + libraries in the package.

We say that a binary foo directly uses a library libbar if it is explicitly linked - with that library (that is, it uses the flag - -lbar during the linking stage). Other + with that library (that is, the library is listed in the ELF + NEEDED attribute, caused by adding -lbar + to the link line when the binary is created). Other libraries that are needed by libbar are linked indirectly to foo, and the dynamic linker will load them automatically when it loads - libbar. A package should depend on - the libraries it directly uses, and the dependencies for - those libraries should automatically pull in the other - libraries. -

- -

- Unfortunately, the ldd program shows both - the directly and indirectly used libraries, meaning that - the dependencies determined included both direct and - indirect dependencies. The use of objdump - avoids this problem by determining only the directly - used libraries. + libbar. A package should depend on the libraries + it directly uses, but not the libraries it indirectly uses. + The dependencies for those libraries will automatically pull + in the other libraries.

A good example of where this helps is the following. We could update libimlib with a new version that - supports a new graphics format called dgf (but retaining - the same major version number). If we used the old - ldd method, every package that uses - libimlib would need to be recompiled so it - would also depend on libdgf or it wouldn't run - due to missing symbols. However with the new system, - packages using libimlib can rely on - libimlib itself having the dependency on - libdgf and so they would not need rebuilding. + supports a new graphics format called dgf (but retaining the + same major version number) and depends on libdgf. + If we used ldd to add dependencies for every + library directly or indirectly linked with a binary, every + package that uses libimlib would need to be + recompiled so it would also depend on libdgf or it + wouldn't run due to missing symbols. Since dependencies are + only added based on ELF NEEDED attribute, packages + using libimlib can rely on libimlib itself + having the dependency on libdgf and so they would + not need rebuilding.

@@ -5462,8 +5684,13 @@ Replaces: mail-transport-agent

debian/shlibs.local

- This lists overrides for this package. Its use is - described below (see ). + This lists overrides for this package. This file should + normally not be used, but may be needed temporarily in + unusual situations to work around bugs in other packages, + or in unusual cases where the normally declared dependency + information in the installed shlibs file for + a library cannot be used. This file overrides information + obtained from any other source.

@@ -5481,38 +5708,34 @@ Replaces: mail-transport-agent

DEBIAN/shlibs files in the "build directory"

- When packages are being built, any - debian/shlibs files are copied into the - control file area of the temporary build directory and - given the name shlibs. These files give - details of any shared libraries included in the - package. - An example may help here. Let us say that the - source package foo generates two binary - packages, libfoo2 and - foo-runtime. When building the binary - packages, the two packages are created in the - directories debian/libfoo2 and - debian/foo-runtime respectively. - (debian/tmp could be used instead of one - of these.) Since libfoo2 provides the - libfoo shared library, it will require a - shlibs file, which will be installed in - debian/libfoo2/DEBIAN/shlibs, eventually - to become - /var/lib/dpkg/info/libfoo2.shlibs. Then - when dpkg-shlibdeps is run on the - executable - debian/foo-runtime/usr/bin/foo-prog, it - will examine the - debian/libfoo2/DEBIAN/shlibs file to - determine whether foo-prog's library - dependencies are satisfied by any of the libraries - provided by libfoo2. For this reason, - dpkg-shlibdeps must only be run once - all of the individual binary packages' - shlibs files have been installed into the - build directory. + When packages are being built, + any debian/shlibs files are copied into the + control information file area of the temporary build + directory and given the name shlibs. These + files give details of any shared libraries included in the + same package. + An example may help here. Let us say that the source + package foo generates two binary + packages, libfoo2 and foo-runtime. + When building the binary packages, the two packages are + created in the directories debian/libfoo2 + and debian/foo-runtime respectively. + (debian/tmp could be used instead of one of + these.) Since libfoo2 provides the + libfoo shared library, it will require a + shlibs file, which will be installed in + debian/libfoo2/DEBIAN/shlibs, eventually to + become /var/lib/dpkg/info/libfoo2.shlibs. + When dpkg-shlibdeps is run on the + executable debian/foo-runtime/usr/bin/foo-prog, + it will examine + the debian/libfoo2/DEBIAN/shlibs file to + determine whether foo-prog's library + dependencies are satisfied by any of the libraries + provided by libfoo2. For this reason, + dpkg-shlibdeps must only be run once all of + the individual binary packages' shlibs files + have been installed into the build directory.

@@ -5558,10 +5781,9 @@ dpkg-shlibdeps debian/tmp/usr/bin/* debian/tmp/usr/sbin/* \ Otherwise, you will need to explicitly list the compiled binaries and libraries. - If you are using debhelper, the - dh_shlibdeps program will do this work for - you. It will also correctly handle multi-binary - packages. + If you are using debhelper, the + dh_shlibdeps program will do this work for you. + It will also correctly handle multi-binary packages.

@@ -5573,13 +5795,6 @@ dpkg-shlibdeps debian/tmp/usr/bin/* debian/tmp/usr/sbin/* \ field in the control file for this to work.

-

- If dpkg-shlibdeps doesn't complain, you're - done. If it does complain you might need to create your own - debian/shlibs.local file, as explained below (see - ). -

-

If you have multiple binary packages, you will need to call dpkg-shlibdeps on each one which contains @@ -5593,16 +5808,17 @@ dpkg-shlibdeps debian/tmp/usr/bin/* debian/tmp/usr/sbin/* \ you will need to specify that dpkg-shlibdeps should use the dependency line of type udeb by adding the -tudeb option - dh_shlibdeps from the debhelper suite - will automatically add this option if it knows it is - processing a udeb. - . If there is no dependency line of type udeb - in the shlibs file, dpkg-shlibdeps will - fall back to the regular dependency line. + dh_shlibdeps from the debhelper suite + will automatically add this option if it knows it is + processing a udeb. + . If there is no dependency line of + type udeb in the shlibs + file, dpkg-shlibdeps will fall back to the regular + dependency line.

- For more details on dpkg-shlibdeps, please see + For more details on dpkg-shlibdeps, please see and .

@@ -5646,13 +5862,17 @@ dpkg-shlibdeps debian/tmp/usr/bin/* debian/tmp/usr/sbin/* \ usually of the form name.so.major-version, in our example, libz.so.1. - This can be determined using the command - + This can be determined using the command + objdump -p /usr/lib/libz.so.1.1.3 | grep SONAME - + The version part is the part which comes after - .so., so in our case, it is 1. + .so., so in our case, it is 1. The soname may + instead be of the form + name-major-version.so, such + as libdb-4.8.so, in which case the name would + be libdb and the version would be 4.8.

@@ -5694,7 +5914,8 @@ udeb: libz 1 zlib1g-udeb (>= 1:1.1.3) It is usual to call this file debian/shlibs (but if you have multiple binary packages, you might want to call it debian/shlibs.package instead). Then - let debian/rules install it in the control area: + let debian/rules install it in the control + information file area: install -m644 debian/shlibs debian/tmp/DEBIAN @@ -5703,14 +5924,15 @@ install -m644 debian/shlibs debian/tmp/DEBIAN install -m644 debian/shlibs.package debian/package/DEBIAN/shlibs An alternative way of doing this is to create the - shlibs file in the control area directly from - debian/rules without using a debian/shlibs - file at all, - This is what dh_makeshlibs in the - debhelper suite does. If your package also has a udeb - that provides a shared library, dh_makeshlibs can - automatically generate the udeb: lines if you specify - the name of the udeb with the --add-udeb option. + shlibs file in the control information file area + directly from debian/rules without using + a debian/shlibs file at all, + This is what dh_makeshlibs in + the debhelper suite does. If your package + also has a udeb that provides a shared + library, dh_makeshlibs can automatically generate + the udeb: lines if you specify the name of the udeb + with the --add-udeb option. since the debian/shlibs file itself is ignored by dpkg-shlibdeps. @@ -5725,74 +5947,7 @@ install -m644 debian/shlibs.package debian/package/DEBIAN/ packages.

- - - Writing the debian/shlibs.local file - -

- This file is intended only as a temporary fix if - your binaries or libraries depend on a library whose package - does not yet provide a correct shlibs file. -

- -

- We will assume that you are trying to package a binary - foo. When you try running - dpkg-shlibdeps you get the following error - message (-O displays the dependency information on - stdout instead of writing it to - debian/substvars, and the lines have been wrapped - for ease of reading): - -$ dpkg-shlibdeps -O debian/tmp/usr/bin/foo -dpkg-shlibdeps: warning: unable to find dependency - information for shared library libbar (soname 1, - path /usr/lib/libbar.so.1, dependency field Depends) -shlibs:Depends=libc6 (>= 2.2.2-2) - - You can then run ldd on the binary to find the - full location of the library concerned: - -$ ldd foo -libbar.so.1 => /usr/lib/libbar.so.1 (0x4001e000) -libc.so.6 => /lib/libc.so.6 (0x40032000) -/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000) - - So the foo binary depends on the - libbar shared library, but no package seems to - provide a *.shlibs file handling - libbar.so.1 in /var/lib/dpkg/info/. Let's - determine the package responsible: - -$ dpkg -S /usr/lib/libbar.so.1 -bar1: /usr/lib/libbar.so.1 -$ dpkg -s bar1 | grep Version -Version: 1.0-1 - - This tells us that the bar1 package, version 1.0-1, - is the one we are using. Now we can file a bug against the - bar1 package and create our own - debian/shlibs.local to locally fix the problem. - Including the following line into your - debian/shlibs.local file: - -libbar 1 bar1 (>= 1.0-1) - - should allow the package build to work. -

- -

- As soon as the maintainer of bar1 provides a - correct shlibs file, you should remove this line - from your debian/shlibs.local file. (You should - probably also then have a versioned Build-Depends - on bar1 to help ensure that others do not have the - same problem building your package.) -

- - - @@ -7283,10 +7438,10 @@ INSTALL = install -s # (or use strip on the files in debian/tmp) for C files) will need to be compiled twice, for the normal case.

+

- You must specify the gcc option -D_REENTRANT - when building a library (either static or shared) to make - the library compatible with LinuxThreads. + Libraries should be built with threading support and to be + thread-safe if the library supports this.

@@ -7343,40 +7498,58 @@ strip --strip-unneeded your-lib

- An ever increasing number of packages are using - libtool to do their linking. The latest GNU - libtools (>= 1.3a) can take advantage of the metadata in the - installed libtool archive files (*.la - files). The main advantage of libtool's - .la files is that it allows libtool to - store and subsequently access metadata with respect to the - libraries it builds. libtool will search for - those files, which contain a lot of useful information about - a library (such as library dependency information for static - linking). Also, they're essential for programs - using libltdl. - Although libtool is fully capable of - linking against shared libraries which don't have - .la files, as it is a mere shell script it can - add considerably to the build time of a - libtool-using package if that shell script - has to derive all this information from first principles - for each library every time it is linked. With the - advent of libtool version 1.4 (and to a - lesser extent libtool version 1.3), the - .la files also store information about - inter-library dependencies which cannot necessarily be - derived after the .la file is deleted. + Packages that use libtool to create and install + their shared libraries install a file containing additional + metadata (ending in .la) alongside the library. + For public libraries intended for use by other packages, these + files normally should not be included in the Debian package, + since the information they include is not necessary to link with + the shared library on Debian and can add unnecessary additional + dependencies to other programs or libraries. + These files store, among other things, all libraries on which + that shared library depends. Unfortunately, if + the .la file is present and contains that + dependency information, using libtool when + linking against that library will cause the resulting program + or library to be linked against those dependencies as well, + even if this is unnecessary. This can create unneeded + dependencies on shared library packages that would otherwise + be hidden behind the library ABI, and can make library + transitions to new SONAMEs unnecessarily complicated and + difficult to manage. + If the .la file is required for that library (if, + for instance, it's loaded via libltdl in a way that + requires that meta-information), the dependency_libs + setting in the .la file should normally be set to + the empty string. If the shared library development package has + historically included the .la, it must be retained + in the development package (with dependency_libs + emptied) until all libraries that depend on it have removed or + emptied dependency_libs in their .la + files to prevent linking with those other libraries + using libtool from failing. +

+ +

+ If the .la must be included, it should be included + in the development (-dev) package, unless the library + will be loaded by libtool's libltdl + library. If it is intended for use with libltdl, + the .la files must go in the run-time library + package.

- Packages that use libtool to create shared - libraries should include the .la files in the - -dev package, unless the package relies on - libtool's libltdl library, in which case - the .la files must go in the run-time library - package. + These requirements for handling of .la files do not + apply to loadable modules or libraries not installed in + directories searched by default by the dynamic linker. Packages + installing loadable modules will frequently need to install + the .la files alongside the modules so that they + can be loaded by libltdl. dependency_libs + does not need to be modified for libraries or modules that are + not installed in directories searched by the dynamic linker by + default and not intended for use by other packages.

@@ -7959,7 +8132,7 @@ endscript

- + Permissions and owners

@@ -8286,10 +8459,14 @@ done

These two files are managed through the dpkg - "alternatives" mechanism. Thus every package providing an - editor or pager must call the - update-alternatives script to register these - programs. + "alternatives" mechanism. Every package providing an editor or + pager must call the update-alternatives script to + register as an alternative for /usr/bin/editor + or /usr/bin/pager as appropriate. The alternative + should have a slave alternative + for /usr/share/man/man1/editor.1.gz + or /usr/share/man/man1/pager.1.gz pointing to the + corresponding manual page.

@@ -8338,11 +8515,13 @@ done /usr/lib/cgi-bin/cgi-bin-name - and should be referred to as + or a subdirectory of that directory, and should be + referred to as http://localhost/cgi-bin/cgi-bin-name - + (possibly with a subdirectory name + before cgi-bin-name). @@ -8498,8 +8677,7 @@ http://localhost/doc/package/filename this so programs should not fail if newaliases cannot be found. Note that because of this, all MTA packages must have Provides, Conflicts and - Replaces: mail-transport-agent control file - fields. + Replaces: mail-transport-agent control fields.

@@ -8608,8 +8786,9 @@ name ["syshostname"]:

Packages that provide an X server that, directly or indirectly, communicates with real input and display - hardware should declare in their control data that they - provide the virtual package xserver. + hardware should declare in their Provides control + field that they provide the virtual + package xserver. This implements current practice, and provides an actual policy for usage of the xserver virtual package which appears in the virtual packages @@ -8627,12 +8806,14 @@ name ["syshostname"]:

Packages that provide a terminal emulator for the X Window - System which meet the criteria listed below should declare - in their control data that they provide the virtual - package x-terminal-emulator. They should also - register themselves as an alternative for + System which meet the criteria listed below should declare in + their Provides control field that they provide the + virtual package x-terminal-emulator. They should + also register themselves as an alternative for /usr/bin/x-terminal-emulator, with a priority of - 20. + 20. That alternative should have a slave alternative + for /usr/share/man/man1/x-terminal-emulator.1.gz + pointing to the corresponding manual page.

@@ -8673,9 +8854,9 @@ name ["syshostname"]:

Packages that provide a window manager should declare in - their control data that they provide the virtual package - x-window-manager. They should also register - themselves as an alternative for + their Provides control field that they provide the + virtual package x-window-manager. They should also + register themselves as an alternative for /usr/bin/x-window-manager, with a priority calculated as follows: @@ -8709,6 +8890,9 @@ name ["syshostname"]: configuration, add 10 points; otherwise add none. + That alternative should have a slave alternative + for /usr/share/man/man1/x-window-manager.1.gz + pointing to the corresponding manual page.

@@ -8848,8 +9032,8 @@ name ["syshostname"]: Font packages must declare a dependency on - xfonts-utils in their control - data. + xfonts-utils in their Depends + or Pre-Depends control field. @@ -9391,14 +9575,15 @@ END-INFO-DIR-ENTRY

Packages distributed under the Apache license (version 2.0), the - Artistic license, the GNU GPL (version 2 or 3), the GNU LGPL - (versions 2, 2.1, or 3), and the GNU FDL (versions 1.2 or 1.3) - should refer to the corresponding files + Artistic license, the GNU GPL (versions 1, 2, or 3), the GNU + LGPL (versions 2, 2.1, or 3), and the GNU FDL (versions 1.2 or + 1.3) should refer to the corresponding files under /usr/share/common-licenses,

In particular, /usr/share/common-licenses/Apache-2.0, /usr/share/common-licenses/Artistic, + /usr/share/common-licenses/GPL-1, /usr/share/common-licenses/GPL-2, /usr/share/common-licenses/GPL-3, /usr/share/common-licenses/LGPL-2, @@ -9716,13 +9901,13 @@ END-INFO-DIR-ENTRY

It is possible to put other files in the package control - area, but this is not generally a good idea (though they - will largely be ignored). + information file area, but this is not generally a good idea + (though they will largely be ignored).

- Here is a brief list of the control info files supported by - dpkg and a summary of what they're used for. + Here is a brief list of the control information files supported + by dpkg and a summary of what they're used for.

@@ -10593,7 +10778,7 @@ END-INFO-DIR-ENTRY Package_Revision The Debian revision part of the package version was - at one point in a separate control file field. This + at one point in a separate control field. This field went through several names. @@ -10650,7 +10835,7 @@ END-INFO-DIR-ENTRY

- A package may contain a control area file called + A package may contain a control information file called conffiles. This file should be a list of filenames of configuration files needing automatic handling, separated by newlines. The filenames should be absolute pathnames,