Date: 2012-09-20 13:03:00

## Package Manager Specification

Stephen P. Bennett
spb@exherbo.org
Christian Faulhammer
fauli@gentoo.org
Ciaran McCreesh
ciaran.mccreesh@googlemail.com
Ulrich Müller
ulm@gentoo.org
20th September 2012

## Contents

1 Introduction
1.1 Aims and Motivation
1.2 Rationale
1.3 Conventions
2 EAPIs
2.1 Definition
2.2 Defined EAPIs
2.3 Reserved EAPIs
3 Names and Versions
3.1 Restrictions upon Names
3.1.1 Category Names
3.1.2 Package Names
3.1.3 Slot Names
3.1.4 USE Flag Names
3.1.5 Repository Names
3.1.6 Keyword Names
3.1.7 EAPI Names
3.2 Version Specifications
3.3 Version Comparison
3.4 Uniqueness of versions
4 Tree Layout
4.1 Top Level
4.2 Category Directories
4.3 Package Directories
4.4 The Profiles Directory
4.4.1 The profiles.desc file
4.4.2 The thirdpartymirrors file
4.4.3 use.desc and related files
4.4.4 The updates directory
4.5 The Licenses Directory
4.6 The Eclass Directory
4.7 The Metadata Directory
4.7.1 The metadata cache
5 Profiles
5.1 General principles
5.2 Files that make up a profile
5.2.1 The parent file
5.2.2 The eapi file
5.2.3 deprecated
5.2.4 make.defaults
5.2.5 Simple line-based files
5.2.6 packages
5.2.7 packages.build
5.2.8 package.mask
5.2.9 package.provided
5.2.10 package.use
5.2.11 USE masking and forcing
5.3 Profile variables
5.3.1 Incremental Variables
5.3.2 Specific variables and their meanings
6 Ebuild File Format
7 Ebuild-defined Variables
7.1 Metadata invariance
7.2 Mandatory Ebuild-defined Variables
7.3 Optional Ebuild-defined Variables
7.3.1 EAPI
7.3.2 Keywords
7.3.3 RDEPEND value
7.4 Magic Ebuild-defined Variables
8 Dependencies
8.1 Dependency Classes
8.2 Dependency Specification Format
8.2.1 All-of Dependency Specifications
8.2.2 Use-conditional Dependency Specifications
8.2.3 Any-of Dependency Specifications
8.2.4 Exactly-one-of Dependency Specifications
8.2.5 At-most-one-of Dependency Specifications
8.2.6 Package Dependency Specifications
8.2.7 Use State Constraints
8.2.8 Restrict
8.2.9 Properties
8.2.10 SRC_URI
9 Ebuild-defined Functions
9.1 List of Functions
9.1.1 Initial Working Directories
9.1.2 pkg_pretend
9.1.3 pkg_setup
9.1.4 src_unpack
9.1.5 src_prepare
9.1.6 src_configure
9.1.7 src_compile
9.1.8 src_test
9.1.9 src_install
9.1.10 pkg_preinst
9.1.11 pkg_postinst
9.1.12 pkg_prerm
9.1.13 pkg_postrm
9.1.14 pkg_config
9.1.15 pkg_info
9.1.16 pkg_nofetch
9.1.17 default_ Phase Functions
9.2 Call Order
10 Eclasses
10.1 The inherit command
10.2 Eclass-defined Metadata Keys
10.3 EXPORT_FUNCTIONS
11 The Ebuild Environment
11.1 Defined Variables
11.1.1 USE and IUSE Handling
11.1.2 REPLACING_VERSIONS and REPLACED_BY_VERSION
11.1.3 Offset-prefix variables EPREFIX, EROOT and ED
11.2 The state of variables between functions
11.3 Available commands
11.3.1 System commands
11.3.2 Commands provided by package dependencies
11.3.3 Ebuild-specific Commands
11.4 The state of the system between functions
12 Merging and Unmerging
12.1 Overview
12.2 Directories
12.2.1 Permissions
12.2.2 Empty Directories
12.3 Regular Files
12.3.1 Permissions
12.3.2 File modification times
12.3.3 Configuration File Protection
12.4 Symlinks
12.4.1 Rewriting
12.5 Hard links
12.6 Other Files
13 Metadata Cache
13.1 Directory Contents
13.2 Cache File Format
14 Glossary
A metadata.xml
B Unspecified Items
C Historical Curiosities
C.1 If-else use blocks
C.2 cvs Versions
C.3 use.defaults
C.4 Old-style Virtuals
D Feature Availability by EAPI
E Differences Between EAPIs
F Desk Reference

## List of Algorithms

1 Version comparison top-level logic
2 Version comparison logic for numeric components
3 Version comparison logic for each numeric component after the first
4 Version comparison logic for letter components
5 Version comparison logic for suffixes
6 Version comparison logic for each suffix
7 Version comparison logic for revision components
8 USE masking logic
9 econf --libdir logic
10 Determining the library directory

## Listings

10.1 EXPORT_FUNCTIONS example: foo.eclass
11.1 Environment state between functions
11.2 einstall command
C.1 If-else use blocks

## List of Tables

5.1 Profile directory support for masking/forcing use flags in stable versions only
5.2 Profile-defined IUSE injection for EAPIs
7.1 EAPIs supporting IUSE defaults
7.2 EAPIs supporting various ebuild-defined variables
7.3 EAPIs with RDEPEND=DEPEND Default
7.4 EAPIs supporting DEFINED_PHASES
8.1 Dependency classes required to be satisfied for a particular phase function
8.2 EAPIs supporting SRC_URI arrows
8.3 EAPIs supporting REQUIRED_USE ?? groups
8.4 Support for SLOT dependencies and sub-slots in EAPIs
8.5 EAPIs supporting USE dependencies
8.6 Exclamation mark strengths for EAPIs
9.1 EAPIs with S to WORKDIR fallbacks
9.2 EAPIs supporting pkg_pretend
9.3 EAPIs supporting src_prepare
9.4 EAPIs supporting src_configure
9.5 src_compile behaviour for EAPIs
9.6 src_test behaviour for EAPIs
9.7 src_install behaviour for EAPIs
9.8 EAPIs supporting pkg_info on non-installed packages
9.9 EAPIs supporting default_ phase functions
11.1 Defined variables
11.2 EAPIs supporting various added env variables
11.3 EAPIs supporting various removed env variables
11.4 EAPIs supporting offset-prefix env variables
11.5 EAPIs supporting offset-prefix
11.6 find implementation for EAPIs
11.7 EAPI Command Failure Behaviour
11.8 Banned commands
11.9 Extra econf arguments for EAPIs
11.10 EAPIs supporting dodoc -r
11.11 EAPIs supporting doheader and newheader
11.12 EAPIs supporting symlinks for doins
11.13 doman language support options for EAPIs
11.14 EAPIs supporting stdin for new* commands
11.15 EAPIs supporting --host-root for *_version commands
11.16 EAPIs supporting controllable compression
11.17 EAPI Behaviour for Use Queries not in IUSE_EFFECTIVE
11.18 EAPIs supporting empty third argument in use_with and use_enable
11.19 EAPIs supporting usex
11.20 unpack extensions for EAPIs
11.21 EAPIs supporting the default function
12.1 Preservation of file modification times (mtimes)
D.1 Features in EAPIs

### Acknowledgements

Thanks to Mike Kelly (package manager provided utilities, section 11.3.3), Danny van Dyk (ebuild functions, section 9), David Leverton (various sections), Petteri Räty (environment state, section 11.2) and Michał Górny (various sections) for contributions. Thanks also to Mike Frysinger and Brian Harring for proof-reading and suggestions for fixes and/or clarification.

### Copyright and Licence

The bulk of this document is © 2007, 2008, 2009 Stephen Bennett and Ciaran McCreesh. Contributions are owned by their respective authors, and may have been changed substantially before inclusion.

This document is released under the Creative Commons Attribution-Share Alike 3.0 Licence. The full text of this licence can be found at http://creativecommons.org/licenses/by-sa/3.0/.

### Reporting Issues

Issues (inaccuracies, wording problems, omissions etc.) in this document should be reported via Gentoo Bugzilla using product Gentoo Hosted Projects, component PMS/EAPI and the default assignee. There should be one bug per issue, and one issue per bug.

Patches (in git format-patch form if possible) may be submitted either via Bugzilla or to the gentoo-pms@gentoo.org mailing list. Patches will be reviewed by the PMS team, who will do one of the following:

- Accept and apply the patch.
- Explain why the patch cannot be applied as-is. The patch may then be updated and resubmitted if appropriate.
- Reject the patch outright.
- Take special action merited by the individual circumstances.

When reporting issues, remember that this document is not the appropriate place for pushing through changes to the tree or the package manager, except where those changes are bugs.

If any issue cannot be resolved by the PMS team, it may be escalated to the Gentoo Council.

## Chapter 1
Introduction

### 1.1 Aims and Motivation

This document aims to fully describe the format of an ebuild repository and the ebuilds therein, as well as certain aspects of package manager behaviour required to support such a repository.

This document is not designed to be an introduction to ebuild development. Prior knowledge of ebuild creation and an understanding of how the package management system works is assumed; certain less familiar terms are explained in the Glossary in chapter 14.

This document does not specify any user or package manager configuration information.

### 1.2 Rationale

At present the only definition of what an ebuild can assume about its environment, and the only definition of what is valid in an ebuild, is the source code of the latest Portage release and a general consensus about which features are too new to assume availability. This has several drawbacks: not only is it impossible to change any aspect of Portage behaviour without verifying that nothing in the tree relies upon it, but if a new package manager should appear it becomes impossible to fully support such an ill-defined standard.

This document aims to address both of these concerns by defining almost all aspects of what an ebuild repository looks like, and how an ebuild is allowed to behave. Thus, both Portage and other package managers can change aspects of their behaviour not defined here without worry of incompatibilities with any particular repository.

### 1.3 Conventions

Text in teletype is used for filenames or variable names. Italic text is used for terms with a particular technical meaning in places where there may otherwise be ambiguity.

The term package manager is used throughout this document in a broad sense. Although some parts of this document are only relevant to fully featured package managers, many items are equally applicable to tools or other applications that interact with ebuilds or ebuild repositories.

## Chapter 2
EAPIs

### 2.1 Definition

An EAPI can be thought of as a ‘version’ of this specification to which a package conforms. An EAPI value is a string as per section 3.1.7, and is part of an ebuild’s metadata.

If a package manager encounters a package version with an unrecognised EAPI, it must not attempt to perform any operations upon it. It could, for example, ignore the package version entirely (although this can lead to user confusion), or it could mark the package version as masked. A package manager must not use any metadata generated from a package with an unrecognised EAPI.

The package manager must not attempt to perform any kind of comparison test other than equality upon EAPIs.

EAPIs are also used for profile directories, as described in section 5.2.2.

### 2.2 Defined EAPIs

The following EAPIs are defined by this specification:

0
  The ‘original’ base EAPI.
1
  EAPI ‘1’ contains a number of extensions to EAPI ‘0’. Except where explicitly noted, it is in all other ways identical to EAPI ‘0’.
2
  EAPI ‘2’ contains a number of extensions to EAPI ‘1’. Except where explicitly noted, it is in all other ways identical to EAPI ‘1’.
3
  EAPI ‘3’ contains a number of extensions to EAPI ‘2’. Except where explicitly noted, it is in all other ways identical to EAPI ‘2’.
4
  EAPI ‘4’ contains a number of extensions to EAPI ‘3’. Except where explicitly noted, it is in all other ways identical to EAPI ‘3’.
5
  EAPI ‘5’ contains a number of extensions to EAPI ‘4’. Except where explicitly noted, it is in all other ways identical to EAPI ‘4’.

Except where explicitly noted, everything in this specification applies to all of the above EAPIs.1

### 2.3 Reserved EAPIs

- EAPIs whose value consists purely of an integer are reserved for future versions of this specification.
- EAPIs whose value starts with the string paludis- are reserved for experimental use by the Paludis package manager.

## Chapter 3
Names and Versions

### 3.1 Restrictions upon Names

No name may be empty. Package managers must not impose fixed upper boundaries upon the length of any name. A package manager should indicate or reject any name that is invalid according to these rules.

#### 3.1.1 Category Names

A category name may contain any of the characters [A-Za-z0-9+_.-]. It must not begin with a hyphen, a dot or a plus sign.

Note: A hyphen is not required because of the virtual category. Usually, however, category names will contain a hyphen.

#### 3.1.2 Package Names

A package name may contain any of the characters [A-Za-z0-9+_-]. It must not begin with a hyphen or a plus sign, and must not end in a hyphen followed by one or more digits.

Note: A package name does not include the category. The term qualified package name is used where a category/package pair is meant.

#### 3.1.3 Slot Names

A slot name may contain any of the characters [A-Za-z0-9+_.-]. It must not begin with a hyphen, a dot or a plus sign.

#### 3.1.4 USE Flag Names

A USE flag name may contain any of the characters [A-Za-z0-9+_@-]. It must begin with an alphanumeric character. Underscores should be considered reserved for USE_EXPAND, as described in section 11.1.1.

Note: The at-sign is required for LINGUAS.

#### 3.1.5 Repository Names

A repository name may contain any of the characters [A-Za-z0-9_-]. It must not begin with a hyphen. In addition, every repository name must also be a valid package name.

#### 3.1.6 Keyword Names

A keyword name may contain any of the characters [A-Za-z0-9_-]. It must not begin with a hyphen. In contexts where it makes sense to do so, a keyword name may be prefixed by a tilde or a hyphen. In KEYWORDS, -* is also acceptable as a keyword.

#### 3.1.7 EAPI Names

An EAPI name may contain any of the characters [A-Za-z0-9+_.-]. It must not begin with a hyphen, a dot or a plus sign.

### 3.2 Version Specifications

The package manager must not impose fixed limits upon the number of version components. Package managers should indicate or reject any version that is invalid according to these rules.

A version starts with the number part, which is in the form [0-9]+(\.[0-9]+)* (a positive integer, followed by zero or more dot-prefixed positive integers).

This may optionally be followed by one of [a-z] (a lowercase letter).

This may be followed by zero or more of the suffixes _alpha, _beta, _pre, _rc or _p, which themselves may be suffixed by an optional integer.

This may optionally be followed by the suffix -r followed immediately by an integer (the “revision number”). If this suffix is not present, it is assumed to be -r0.

### 3.3 Version Comparison

Version specifications are compared component by component, moving from left to right, as detailed in Algorithm 1 and sub-algorithms. If a sub-algorithm returns a decision, then that is the result of the whole comparison; if it terminates without returning a decision, the process continues from the point from which it was invoked.

Algorithm 1: Version comparison top-level logic
1: let A and B be the versions to be compared
2: compare numeric components using Algorithm 2
3: compare letter components using Algorithm 4
4: compare suffixes using Algorithm 5
5: compare revision components using Algorithm 7
6: return A = B

Algorithm 2: Version comparison logic for numeric components
1: define the notations Ank and Bnk to mean the kth numeric component of A and B respectively, using 0-based indexing
2: if An0 > Bn0 using integer comparison then
3: return A > B
4: else if An0 < Bn0 using integer comparison then
5: return A < B
6: end if
7: let Ann be the number of numeric components of A
8: let Bnn be the number of numeric components of B
9: for all i such that i ≥ 1 and i < Ann and i < Bnn, in ascending order do
10: compare Ani and Bni using Algorithm 3
11: end for
12: if Ann > Bnn then
13: return A > B
14: else if Ann < Bnn then
15: return A < B
16: end if

Algorithm 3: Version comparison logic for each numeric component after the first
1: if either Ani or Bni has a leading 0 then
2: let An′i be Ani with any trailing 0s removed
3: let Bn′i be Bni with any trailing 0s removed
4: if An′i > Bn′i using ASCII stringwise comparison then
5: return A > B
6: else if An′i < Bn′i using ASCII stringwise comparison then
7: return A < B
8: end if
9: else
10: if Ani > Bni using integer comparison then
11: return A > B
12: else if Ani < Bni using integer comparison then
13: return A < B
14: end if
15: end if

Algorithm 4: Version comparison logic for letter components
1: let Al be the letter component of A if any, otherwise the empty string
2: let Bl be the letter component of B if any, otherwise the empty string
3: if Al > Bl using ASCII stringwise comparison then
4: return A > B
5: else if Al < Bl using ASCII stringwise comparison then
6: return A < B
7: end if

Algorithm 5: Version comparison logic for suffixes
1: define the notations Ask and Bsk to mean the kth suffix of A and B respectively, using 0-based indexing
2: let Asn be the number of suffixes of A
3: let Bsn be the number of suffixes of B
4: for all i such that i ≥ 0 and i < Asn and i < Bsn, in ascending order do
5: compare Asi and Bsi using Algorithm 6
6: end for
7: if Asn > Bsn then
8: if AsBsn is of type _p then
9: return A > B
10: else
11: return A < B
12: end if
13: else if Asn < Bsn then
14: if BsAsn is of type _p then
15: return A < B
16: else
17: return A > B
18: end if
19: end if

Algorithm 6: Version comparison logic for each suffix
1: if Asi and Bsi are of the same type (_alpha vs _beta etc) then
2: let As′i be the integer part of Asi if any, otherwise 0
3: let Bs′i be the integer part of Bsi if any, otherwise 0
4: if As′i > Bs′i, using integer comparison then
5: return A > B
6: else if As′i < Bs′i, using integer comparison then
7: return A < B
8: end if
9: else if the type of Asi is greater than the type of Bsi using the ordering _alpha < _beta < _pre < _rc < _p then
10: return A > B
11: else
12: return A < B
13: end if

Algorithm 7: Version comparison logic for revision components
1: let Ar be the integer part of the revision component of A if any, otherwise 0
2: let Br be the integer part of the revision component of B if any, otherwise 0
3: if Ar > Br using integer comparison then
4: return A > B
5: else if Ar < Br using integer comparison then
6: return A < B
7: end if

### 3.4 Uniqueness of versions

No two packages in a given repository may have the same qualified package name and equal versions. For example, a repository may not contain more than one of foo-bar/baz-1.0.2, foo-bar/baz-1.0.2-r0 and foo-bar/baz-1.000.2.

## Chapter 4
Tree Layout

This chapter defines the layout on-disk of an ebuild repository. In all cases below where a file or directory is specified, a symlink to a file or directory is also valid. In this case, the package manager must follow the operating system’s semantics for symbolic links and must not behave differently from normal.

### 4.1 Top Level

An ebuild repository shall occupy one directory on disk, with the following subdirectories:

- One directory per category, whose name shall be the name of the category. The layout of these directories shall be as described in section 4.2.
- A profiles directory, described in section 4.4.
- A licenses directory (optional), described in section 4.5.
- An eclass directory (optional), described in section 4.6.
- A metadata directory (optional), described in section 4.7.
- Other optional support files and directories (skeleton ebuilds or ChangeLogs, for example) may exist but are not covered by this specification. The package manager must ignore any of these files or directories that it does not recognise.

### 4.2 Category Directories

Each category provided by the repository (see also: the profiles/categories file, section 4.4) shall be contained in one directory, whose name shall be that of the category. Each category directory shall contain:

- A metadata.xml file, as described in appendix A. Optional.
- Zero or more package directories, one for each package in the category, as described in section 4.3. The name of the package directory shall be the corresponding package name.

Category directories may contain additional files, whose purpose is not covered by this specification. Additional directories that are not for a package may not be present, to avoid conflicts with package name directories; an exception is made for filesystem components whose name starts with a dot, which the package manager must ignore, and for any directory named CVS.

It is not required that a directory exists for each category provided by the repository. A category directory that does not exist shall be considered equivalent to an empty category (and by extension, a package manager may treat an empty category as a category that does not exist).

### 4.3 Package Directories

A package directory contains the following:

- Zero or more ebuilds. These are as described in section 6 and others.
- A metadata.xml file, as described in appendix A. Optional only for legacy support.
- A ChangeLog, in a format determined by the provider of the repository. Optional.
- A Manifest file, whose format is described in [1].
- A files directory, containing any support files needed by the ebuilds. Optional.

Any ebuild in a package directory must be named name-ver.suffix, where:

- name is the (unqualified) package name.
- ver is the package’s version.
- suffix is ebuild.

Package managers must ignore any ebuild file that does not match these rules.

A package directory that contains no correctly named ebuilds shall be considered a package with no versions. A package with no versions shall be considered equivalent to a package that does not exist (and by extension, a package manager may treat a package that does not exist as a package with no versions).

A package directory may contain other files or directories, whose purpose is not covered by this specification.

### 4.4 The Profiles Directory

The profiles directory shall contain zero or more profile directories as described in section 5, as well as the following files and directories. In any line-based file, lines beginning with a # character are treated as comments, whilst blank lines are ignored. All contents of this directory, with the exception of repo_name, are optional.

The profiles directory may contain an eapi file. This file, if it exists, must contain a single line with the name of an EAPI. This specifies the EAPI to use when handling the profiles directory; a package manager must not attempt to use any repository whose profile directory requires an EAPI it does not support. If no eapi file is present, EAPI 0 shall be used.

If the repository is not intended to be stand-alone, the contents of these files are to be taken from or merged with the master repository as necessary.

Other files not described by this specification may exist, but may not be relied upon. The package manager must ignore any files in this directory that it does not recognise.

arch.list
  Contains a list, one entry per line, of permissible values for the ARCH variable, and hence permissible keywords for packages in this repository.
categories
  Contains a list, one entry per line, of categories provided by this repository.
eapi
  See above.
info_pkgs
  Contains a list, one entry per line, of qualified package names. Any package matching one of these is to be listed when a package manager displays a ‘system information’ listing.
info_vars
  Contains a list, one entry per line, of profile, configuration, and environment variables which are considered to be of interest. The value of each of these variables may be shown when the package manager displays a ‘system information’ listing.
package.mask
  Contains a list, one entry per line, of package dependency specifications (using the directory’s EAPI). Any package version matching one of these is considered to be masked, and will not be installed regardless of profile unless it is unmasked by the user configuration.
profiles.desc
  Described below in section 4.4.1.
repo_name
  Contains, on a single line, the name of this repository. The repository name must conform to section 3.1.5.
thirdpartymirrors
  Described below in section 4.4.2.
use.desc
  Contains descriptions of valid global USE flags for this repository. The format is described in section 4.4.3.
use.local.desc
  Contains descriptions of valid local USE flags for this repository, along with the packages to which they apply. The format is as described in section 4.4.3.
desc/
  This directory contains files analogous to use.desc for the various USE_EXPAND variables. Each file in it is named <varname>.desc, where <varname> is the variable name, in lowercase, whose possible values the file describes. The format of each file is as for use.desc, described in section 4.4.3. The USE_EXPAND name is not included as a prefix here.
updates/
  This directory is described in section 4.4.4.

#### 4.4.1 The profiles.desc file

profiles.desc is a line-based file, with the standard commenting rules from section 4.4, containing a list of profiles that are valid for use, along with their associated architecture and status. Each line has the format:

<keyword> <profile path> <stability>

Where:

- <keyword> is the default keyword for the profile and the ARCH for which the profile is valid.
- <profile path> is the (relative) path from the profiles directory to the profile in question.
- <stability> indicates the stability of the profile. This may be useful for QA tools, which may wish to display warnings with a reduced severity for some profiles. The values stable and dev are widely used, but repositories may use other values.

Fields are whitespace-delimited.

#### 4.4.2 The thirdpartymirrors file

thirdpartymirrors is another simple line-based file, describing the valid mirrors for use with mirror:// URIs in this repository, and the associated download locations. The format of each line is:

<mirror name> <mirror 1> <mirror 2> ... <mirror n>

Fields are whitespace-delimited. When parsing a URI of the form mirror://name/path/filename, where the path/ part is optional, the thirdpartymirrors file is searched for a line whose first field is name. Then the download URIs in the subsequent fields have path/filename appended to them to generate the URIs from which a download is attempted.

Each mirror name may appear at most once in a file. Behaviour when a mirror name appears multiple times is undefined. Behaviour when a mirror is defined in terms of another mirror is undefined. A package manager may choose to fetch from all of or a subset of the listed mirrors, and may use an order other than the one described.

The mirror with the name equal to the repository’s name (and if the repository has a master, the master’s name) may be consulted for all downloads.

#### 4.4.3 use.desc and related files

use.desc contains descriptions of every valid global USE flag for this repository. It is a line-based file with the standard rules for comments and blank lines. The format of each line is:

<flagname> - <description>

use.local.desc contains descriptions of every valid local USE flag—those that apply only to a small number of packages, or that have different meanings for different packages. Its format is:

<category/package>:<flagname> - <description>

Flags must be listed once for each package to which they apply, or if a flag is listed in both use.desc and use.local.desc, it must be listed once for each package for which its meaning differs from that described in use.desc.

#### 4.4.4 The updates directory

The updates directory is used to inform the package manager that a package has moved categories, names, or that a version has changed SLOT. It contains one file per quarter year, named [1-4]Q-[YYYY] for the first to fourth quarter of a given year, for example 1Q-2004 or 3Q-2006. The format of each file is again line-based, with each line having one of the following formats:

move <qpn1> <qpn2>
slotmove <spec> <slot1> <slot2>

The first form, where qpn1 and qpn2 are qualified package names, instructs the package manager that the package qpn1 has changed name, category, or both, and is now called qpn2.

The second form instructs the package manager that any currently installed package version matching package dependency specification spec whose SLOT is set to slot1 should have it updated to slot2.

Any name that has appeared as the origin of a move must not be reused in the future. Any slot that has appeared as the origin of a slot move may not be used by packages matching the spec of that slot move in the future.

### 4.5 The Licenses Directory

The licenses directory shall contain copies of the licenses used by packages in the repository. Each file will be named according to the name used in the LICENSE variable as described in section 7.3, and will contain the complete text of the license in human-readable form. Plain text format is strongly preferred but not required.

### 4.6 The Eclass Directory

The eclass directory shall contain copies of the eclasses provided by this repository. The format of these files is described in section 10. It may also contain, in their own directory, support files needed by these eclasses.

### 4.7 The Metadata Directory

The metadata directory contains various repository-level metadata that is not contained in profiles/. All contents are optional. In this standard only the cache subdirectory is described; other contents are optional but may include security advisories, DTD files for the various XML files used in the repository, and repository timestamps.

#### 4.7.1 The metadata cache

The metadata/cache directory may contain a cached form of all important ebuild metadata variables. The contents of this directory are described in section 13.

## Chapter 5
Profiles

### 5.1 General principles

Generally, a profile defines information specific to a certain ‘type’ of system—it lies somewhere between repository-level defaults and user configuration in that the information it contains is not necessarily applicable to all machines, but is sufficiently general that it should not be left to the user to configure it. Some parts of the profile can be overridden by user configuration, some only by another profile.

The format of a profile is relatively simple. Each profile is a directory containing any number of the files described in this chapter, and possibly inheriting another profile. The files themselves follow a few basic conventions as regards inheritance and format; these are described in the next section. It may also contain any number of subdirectories containing other profiles.

### 5.2 Files that make up a profile

#### 5.2.1 The parent file

A profile may contain a parent file. Each line must contain a relative path to another profile which will be considered as one of this profile’s parents. Any settings from the parent are inherited by this profile, and can be overridden by it. Precise rules for how settings are combined with the parent profile vary between files, and are described below. Parents are handled depth first, left to right, with duplicate parent paths being sourced for every time they are encountered.

It is illegal for a profile’s parent tree to contain cycles. Package manager behaviour upon encountering a cycle is undefined.

This file must not contain comments, blank lines or make use of line continuations.

#### 5.2.2 The eapi file

A profile directory may contain an eapi file. This file, if it exists, must contain a single line with the name of an EAPI. This specifies the EAPI to use when handling the directory in question; a package manager must not attempt to use any profile using a directory which requires an EAPI it does not support. If no eapi file is present, EAPI 0 shall be used. The EAPI is not inherited via the parent file.

#### 5.2.3 deprecated

If a profile contains a file named deprecated, it is treated as such. The first line of this file should contain the path from the profiles directory of the repository to a valid profile that is the recommended upgrade path from this profile. The remainder of the file can contain any text, which may be displayed to users using this profile by the package manager. This file is not inherited—profiles which inherit from a deprecated profile are not deprecated.

This file must not contain comments or make use of line continuations.

#### 5.2.4 make.defaults

make.defaults is used to define defaults for various environment and configuration variables. This file is unusual in that it is not combined at a file level with the parent—instead, each variable is combined or overridden individually as described in section 5.3.

The file itself is a line-based key-value format. Each line contains a single VAR="value" entry, where the value must be double quoted. A variable name must start with one of a-zA-Z and may contain a-zA-Z0-9_ only. Additional syntax, which is a small subset of bash syntax, is allowed as follows:

- Variables to the right of the equals sign in the form ${foo} or $foo are recognised and expanded from variables previously set in this or earlier make.defaults files.
- One logical line may be continued over multiple physical lines by escaping the newline with a backslash. A quoted string may be continued over multiple physical lines by either a simple newline or a backslash-escaped newline.
- Backslashes, except for line continuations, are not allowed.

#### 5.2.5 Simple line-based files

These files are a simple one-item-per-line list, which is inherited in the following manner: the parent profile’s list is taken, and the current profile’s list appended. If any line begins with a hyphen, then any lines previous to it whose contents are equal to the remainder of that line are removed from the list. Once again, blank lines and those beginning with a # are discarded.

#### 5.2.6 packages

The packages file is used to define the ‘system set’ for this profile. After the above rules for inheritance and comments are applied, its lines must take one of two forms: a package dependency specification prefixed by * denotes that the atom forms part of the system set. A package dependency specification on its own may also appear for legacy reasons, but should be ignored when calculating the system set.

#### 5.2.7 packages.build

The packages.build file is used by Gentoo’s Catalyst tool to generate stage1 tarballs, and has no relevance to the operation of a package manager. It is thus outside the scope of this document, but is mentioned here for completeness.

#### 5.2.8 package.mask

package.mask is used to prevent packages from being installed on a given profile. Each line contains one package dependency specification; anything matching this specification will not be installed unless unmasked by the user’s configuration.

Note that the -spec syntax can be used to remove a mask in a parent profile, but not necessarily a global mask (from profiles/package.mask, section 4.4).

Note: Portage currently treats profiles/package.mask as being on the leftmost branch of the inherit tree when it comes to -lines. This behaviour may not be relied upon.

#### 5.2.9 package.provided

package.provided is used to tell the package manager that a certain package version should be considered to be provided by the system regardless of whether it is actually installed. Because it has severe adverse effects on USE-based and slot-based dependencies, its use is strongly deprecated and package manager support must be regarded as purely optional.

#### 5.2.10 package.use

The package.use file may be used by the package manager to override the default USE flags specified by make.defaults on a per package basis. The format is to have a package dependency specification, and then a space delimited list of USE flags to enable. A USE flag in the form of -flag indicates that the package should have the USE flag disabled. The package dependency specification is limited to the forms defined by the directory’s EAPI.

#### 5.2.11 USE masking and forcing

This section covers the eight files use.mask, use.force, use.stable.mask, use.stable.force, package.use.mask, package.use.force, package.use.stable.mask, and package.use. stable.force. They are described together because they interact in a non-trivial manner.

Simply speaking, use.mask and use.force are used to say that a given USE flag must never or always, respectively, be enabled when using this profile. package.use.mask and package.use.force do the same thing on a per-package, or per-version, basis.

STABLEMASK

In profile directories with an EAPI supporting stable masking, as listed in table 5.1, the same is true for use.stable.mask, use.stable.force, package.use.stable.mask and package.use. stable.force. These files, however, only act on packages that are merged due to a stable keyword in the sense of subsection 7.3.2. Thus, these files can be used to restrict the feature set deemed stable in a package.

Table 5.1: Profile directory support for masking/forcing use flags in stable versions only

EAPI | Supports masking/forcing use flags in stable versions?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

The precise manner in which the eight files interact is less simple, and is best described in terms of the algorithm used to determine whether a flag is masked for a given package version. This is described in Algorithm 8.

Algorithm 8: USE masking logic
1: let masked = false
2: for each profile in the inheritance tree, depth first do
3: if use.mask contains flag then
4: let masked = true
5: else if use.mask contains -flag then
6: let masked = false
7: end if
8: if stable keyword in use then
9: if use.stable.mask contains flag then
10: let masked = true
11: else if use.stable.mask contains -flag then
12: let masked = false
13: end if
14: end if
15: for each line in package.use.mask, in order, for which the spec matches package do
16: if line contains flag then
17: let masked = true
18: else if line contains -flag then
19: let masked = false
20: end if
21: end for
22: if stable keyword in use then
23: for each line in package.use.stable.mask, in order, for which the spec matches package do
24: if line contains flag then
25: let masked = true
26: else if line contains -flag then
27: let masked = false
28: end if
29: end for
30: end if
31: end for

Stable restrictions (“stable keyword in use” in Algorithm 8) are applied exactly if replacing in KEYWORDS all stable keywords by the corresponding tilde prefixed keywords (see subsection 7.3.2) would result in the package installation being prevented due to the KEYWORDS setting.

The logic for use.force, use.stable.force, package.use.force, and package.use. stable.force is identical. If a flag is both masked and forced, the mask is considered to take precedence.

USE_EXPAND values may be forced or masked by using expand_name_value.

A package manager may treat ARCH values that are not the current architecture as being masked.

### 5.3 Profile variables

This section documents variables that have special meaning, or special behaviour, when defined in a profile’s make.defaults file.

#### 5.3.1 Incremental Variables

Incremental variables must stack between parent and child profiles in the following manner: Beginning with the highest parent profile, tokenise the variable’s value based on whitespace and concatenate the lists. Then, for any token T beginning with a hyphen, remove it and any previous tokens whose value is equal to T with the hyphen removed, or, if T is equal to -*, remove all previous values. Note that because of this treatment, the order of tokens in the final result is arbitrary, not necessarily related to the order of tokens in any given profile. The following variables must be treated in this fashion:

- USE
- USE_EXPAND
- USE_EXPAND_HIDDEN
- CONFIG_PROTECT
- CONFIG_PROTECT_MASK

If the package manager supports any EAPI listed in table 5.2 as using profile-defined IUSE injection, the following variables must also be treated incrementally; otherwise, the following variables may or may not be treated incrementally:

- IUSE_IMPLICIT
- USE_EXPAND_IMPLICIT
- USE_EXPAND_UNPREFIXED

Other variables, except where they affect only package-manager-specific functionality (such as Portage’s FEATURES variable), must not be treated incrementally—later definitions shall completely override those in parent profiles.

Table 5.2: Profile-defined IUSE injection for EAPIs

EAPI | Supports profile-defined IUSE injection?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

#### 5.3.2 Specific variables and their meanings

The following variables have specific meanings when set in profiles.

ARCH
  The system’s architecture. Must be a value listed in profiles/arch.list; see section 4.4 for more information. Must be equal to the primary KEYWORD for this profile.
CONFIG_PROTECT, CONFIG_PROTECT_MASK
  Contain whitespace-delimited lists used to control the configuration file protection. Described more fully in chapter 12.3.3.
USE
  Defines the list of default USE flags for this profile. Flags may be added or removed by the user’s configuration. USE_EXPAND values must not be specified in this way.
USE_EXPAND
  Defines a list of variables which are to be treated incrementally and whose contents are to be expanded into the USE variable as passed to ebuilds. See section 11.1.1 for details.
USE_EXPAND_UNPREFIXED
  Similar to USE_EXPAND, but no prefix is used. If the repository contains any package using an EAPI supporting profile-defined IUSE injection (see table 5.2), this list must contain at least ARCH. See section 11.1.1 for details.
USE_EXPAND_HIDDEN
  Contains a (possibly empty) subset of names from USE_ EXPAND and USE_EXPAND_UNPREFIXED. The package manager may use this set as a hint to avoid displaying uninteresting or unhelpful information to an end user.
USE_EXPAND_IMPLICIT, IUSE_IMPLICIT
  Used to inject implicit values into IUSE. See section 11.1.1 for details.

In addition, for EAPIs listed in table 5.2 as supporting profile defined IUSE injection, the variables named in USE_EXPAND and USE_EXPAND_UNPREFIXED have special handling as described in section 11.1.1.

Any other variables set in make.defaults must be passed on into the ebuild environment as-is, and are not required to be interpreted by the package manager.

## Chapter 6
Ebuild File Format

The ebuild file format is in its basic form a subset of the format of a bash script. The interpreter is assumed to be GNU bash, version 3.2 or later, see footnote 5 on page 189. The file encoding must be UTF-8 with Unix-style newlines. When sourced, the ebuild must define certain variables and functions (see sections 7 and 9 for specific information), and must not call any external programs, write anything to standard output or standard error, or modify the state of the system in any way.

## Chapter 7
Ebuild-defined Variables

Note: This section describes variables that may or must be defined by ebuilds. For variables that are passed from the package manager to the ebuild, see section 11.1.

If any of these variables are set to invalid values, or if any of the mandatory variables are undefined, the package manager’s behaviour is undefined; ideally, an error in one ebuild should not prevent operations upon other ebuilds or packages.

### 7.1 Metadata invariance

All ebuild-defined variables discussed in this chapter must be defined independently of any system, profile or tree dependent data, and must not vary depending upon the ebuild phase. In particular, ebuild metadata can and will be generated on a different system from that upon which the ebuild will be used, and the ebuild must generate identical metadata every time it is used.

Globally defined ebuild variables without a special meaning must similarly not rely upon variable data.

### 7.2 Mandatory Ebuild-defined Variables

All ebuilds must define at least the following variables:

DESCRIPTION
  A short human-readable description of the package’s purpose. May be defined by an eclass. Must not be empty.
SLOT
  The package’s slot. Must be a valid slot name, as per section 3.1.3. May be defined by an eclass. Must not be empty.

  In EAPIs shown in table 8.4 as supporting sub-slots, the SLOT variable may contain an optional sub-slot part that follows the regular slot and is delimited by a / character. The sub-slot must be a valid slot name, as per section 3.1.3. The sub-slot is used to represent cases in which an upgrade to a new version of a package with a different sub-slot may require dependent packages to be rebuilt. When the sub-slot part is omitted from the SLOT definition, the package is considered to have an implicit sub-slot which is equal to the regular slot.

### 7.3 Optional Ebuild-defined Variables

Ebuilds may define any of the following variables:

EAPI
  The EAPI. See below.
HOMEPAGE
  The URI or URIs for a package’s homepage, including protocols. See section 8 for full syntax.
SRC_URI
  A list of source URIs for the package. Valid protocols are http://, https://, ftp:// and mirror:// (see section 4.4.2 for mirror behaviour). Fetch restricted packages may include URL parts consisting of just a filename. See section 8 for full syntax.
LICENSE
  The package’s license. Each text token must correspond to a tree “licenses/” entry (see section 4.5). See section 8 for full syntax.
KEYWORDS
  A whitespace separated list of keywords for the ebuild. Each token must be a valid keyword name, as per section 3.1.6. See section 7.3.2 for full syntax.
IUSE
  The USE flags used by the ebuild. Any eclass that works with USE flags must also set IUSE, listing only the variables used by that eclass. The package manager is responsible for merging these values. See section 11.1.1 for discussion on which values must be listed this variable.

  IUSE-DEFAULTS

  In EAPIs shown in table 7.1 as supporting IUSE defaults, any use flag name in IUSE may be prefixed by at most one of a plus or a minus sign. If such a prefix is present, the package manager may use it as a suggestion as to the default value of the use flag if no other configuration overrides it.

REQUIRED_USE

  REQUIRED-USE Zero or more assertions that must be met by the configuration of USE flags to be valid for this ebuild. See section 8.2.7 for description and section 8 for full syntax. Only in EAPIs listed in table 7.2 as supporting REQUIRED_USE.

PROPERTIES

  PROPERTIES Zero or more properties for this package. See section 8.2.9 for value meanings and section 8 for full syntax. For EAPIs listed in table 7.2 as having optional support, ebuilds must not rely upon the package manager recognising or understanding this variable in any way.

RESTRICT
  Zero or more behaviour restrictions for this package. See section 8.2.8 for value meanings and section 8 for full syntax.
DEPEND
  See section 8.
RDEPEND
  See section 8. For some EAPIs, RDEPEND has special behaviour for its value if unset and when used with an eclass. See section 7.3.3 for details.
PDEPEND
  See section 8.

Table 7.1: EAPIs supporting IUSE defaults

EAPI | Supports IUSE defaults?
0 | No
1 | Yes
2 | Yes
3 | Yes
4 | Yes
5 | Yes

Table 7.2: EAPIs supporting various ebuild-defined variables

EAPI | Supports PROPERTIES? | Supports REQUIRED_USE?
0 | Optionally | No
1 | Optionally | No
2 | Optionally | No
3 | Optionally | No
4 | Yes | Yes
5 | Yes | Yes

#### 7.3.1 EAPI

An empty or unset EAPI value is equivalent to 0. Ebuilds must not assume that they will get a particular one of these two values if they are expecting one of these two values.

The package manager must either pre-set the EAPI variable to 0 or ensure that it is unset before sourcing the ebuild for metadata generation. When using the ebuild for other purposes, the package manager must either pre-set EAPI to the value specified by the ebuild’s metadata or ensure that it is unset.

If any of these variables are set to invalid values, the package manager’s behaviour is undefined; ideally, an error in one ebuild should not prevent operations upon other ebuilds or packages.

If the EAPI is to be specified in an ebuild, the EAPI variable must be assigned to precisely once. The assignment must not be preceded by any lines other than blank lines or those that start with optional whitespace (spaces or tabs) followed by a # character, and the line containing the assignment statement must match the following regular expression:

^[ \t]*EAPI=([’"]?)([A-Za-z0-9+_.-]*)\1[ \t]*([ \t]#.*)?$

The package manager must determine the EAPI of an ebuild by parsing its first non-blank and non-comment line, using the above regular expression. If it matches, the EAPI is the substring matched by the capturing parentheses (0 if empty), otherwise it is 0. For a recognised EAPI, the package manager must make sure that the EAPI value obtained by sourcing the ebuild with bash is identical to the EAPI obtained by parsing. The ebuild must be treated as invalid if these values are different.

#### 7.3.2 Keywords

Keywords are used to indicate levels of stability of a package on a respective architecture arch. The following conventions are used:

- arch: Both the package version and the ebuild are widely tested, known to work and not have any serious issues on the indicated platform. This is referred to as a stable keyword.
- ~arch: The package version and the ebuild are believed to work and do not have any known serious bugs, but more testing is required before the package version is considered suitable for obtaining a stable keyword. This is referred to as an unstable keyword or a testing keyword.
- No keyword: It is not known whether the package will work, or insufficient testing has occurred.
- -arch: The package version will not work on the architecture.

The -* keyword is used to indicate package versions which are not worth trying to test on unlisted architectures.

An empty KEYWORDS variable indicates uncertain functionality on any architecture.

#### 7.3.3 RDEPEND value

RDEPEND-DEPEND

In EAPIs listed in table 7.3 as having RDEPEND=DEPEND, if RDEPEND is unset (but not if it is set to an empty string) in an ebuild, when generating metadata the package manager must treat its value as being equal to the value of DEPEND.

When dealing with eclasses, only values set in the ebuild itself are considered for this behaviour; any DEPEND or RDEPEND set in an eclass does not change the implicit RDEPEND=DEPEND for the ebuild portion, and any DEPEND value set in an eclass does not get treated as being part of RDEPEND.

Table 7.3: EAPIs with RDEPEND=DEPEND Default

EAPI | RDEPEND=DEPEND?
0 | Yes
1 | Yes
2 | Yes
3 | Yes
4 | No
5 | No

### 7.4 Magic Ebuild-defined Variables

The following variables must be defined by inherit (see section 10.1, and may be considered to be part of the ebuild’s metadata:

ECLASS
  The current eclass, or unset if there is no current eclass. This is handled magically by inherit and must not be modified manually.
INHERITED
  List of inherited eclass names. Again, this is handled magically by inherit.

Note: Thus, by extension of section 7.1, inherit may not be used conditionally, except upon constant conditions.

The following are special variables defined by the package manager for internal use and may or may not be exported to the ebuild environment:

DEFINED_PHASES

  DEFINED-PHASES A space separated arbitrarily ordered list of phase names (e. g. configure setup unpack) whose phase functions are defined by the ebuild or an eclass inherited by the ebuild. If no phase functions are defined, a single hyphen is used instead of an empty string. For EAPIs listed in table 7.4 as having optional DEFINED_PHASES support, package managers may not rely upon the metadata cache having this variable defined, and must treat an empty string as “this information is not available”.

Note: Thus, by extension of section 7.1, phase functions must not be defined based upon any variant condition.

Table 7.4: EAPIs supporting DEFINED_PHASES

EAPI | Supports DEFINED_PHASES?
0 | Optionally
1 | Optionally
2 | Optionally
3 | Optionally
4 | Yes
5 | Yes

## Chapter 8
Dependencies

### 8.1 Dependency Classes

Table 8.1: Dependency classes required to be satisfied for a particular phase function

Phase function | Satisfied dependency classes
pkg_pretend, pkg_ setup, pkg_info, pkg_nofetch | None (ebuilds can rely only on the packages in the system set)
src_unpack, src_ prepare, src_ configure, src_ compile, src_test, src_install | DEPEND
pkg_preinst, pkg_postinst, pkg_prerm, pkg_ postrm | RDEPEND (unless the particular dependency results in a circular dependency, in which case it may be installed later)
pkg_config | RDEPEND, PDEPEND

There are three classes of dependencies supported by ebuilds:

- Build dependencies (DEPEND). These must be installed and usable before any of the ebuild src_* phase functions is executed. These may not be installed at all if a binary package is being merged.
- Runtime dependencies (RDEPEND). These must be installed and usable before the results of an ebuild merging are treated as usable.
- Post dependencies (PDEPEND). These must be installed at some point before the package manager finishes the batch of installs.

Table 8.1 lists dependencies which must be satisfied before a particular phase function is executed.

In addition, SRC_URI, HOMEPAGE, RESTRICT, PROPERTIES, LICENSE and REQUIRED_USE use dependency-style specifications to specify their values.

### 8.2 Dependency Specification Format

The following elements are recognised in at least one class of specification. All elements must be surrounded on both sides by whitespace, except at the start and end of the string.

- A package dependency specification. Permitted in DEPEND, RDEPEND, PDEPEND.
- A URI, in the form proto://host/path. Permitted in SRC_URI and HOMEPAGE. In EAPIs listed in table 8.2 as supporting SRC_URI arrows, may optionally be followed by whitespace, then ->, then whitespace, then a simple filename when in SRC_URI. For SRC_URI behaviour, see section 8.2.10.
- A flat filename. Permitted in SRC_URI.
- A license name (e. g. GPL-2). Permitted in LICENSE.
- A use flag name, optionally preceded by an exclamation mark. Permitted in REQUIRED_ USE.
- A simple string. Permitted in RESTRICT and PROPERTIES.
- An all-of group, which consists of an open parenthesis, followed by whitespace, followed by zero or more of (a dependency item of any kind followed by whitespace), followed by a close parenthesis. More formally: all-of ::= ’(’ whitespace (item whitespace)* ’)’. Permitted in all specification style variables.
- An any-of group, which consists of the string ||, followed by whitespace, followed by an open parenthesis, followed by whitespace, followed by zero or more of (a dependency item of any kind followed by whitespace), followed by a close parenthesis. More formally: any-of ::= ’||’ whitespace ’(’ whitespace (item whitespace)* ’)’. Permitted in DEPEND, RDEPEND, PDEPEND, LICENSE, REQUIRED_USE.
- An exactly-one-of group, which consists of the string ^^, followed by whitespace, followed by an open parenthesis, followed by whitespace, followed by zero or more of (a dependency item of any kind followed by whitespace), followed by a close parenthesis. More formally: exactly-one-of ::= ’^^’ whitespace ’(’ whitespace (item whitespace)* ’)’. Permitted in REQUIRED_USE.

- AT-MOST-ONE-OF An at-most-one-of group, which consists of the string ??, followed by whitespace, followed by an open parenthesis, followed by whitespace, followed by zero or more of (a dependency item of any kind followed by whitespace), followed by a close parenthesis. More formally: exactly-one-of ::= ’??’ whitespace ’(’ whitespace (item whitespace)* ’)’. Permitted in REQUIRED_USE in EAPIs listed in table 8.3 as supporting REQUIRED_USE ?? groups.

- A use-conditional group, which consists of an optional exclamation mark, followed by a use flag name, followed by a question mark, followed by whitespace, followed by an open parenthesis, followed by whitespace, followed by zero or more of (a dependency item of any kind followed by whitespace), followed by a close parenthesis. More formally: use-conditional ::= ’!’? flag-name ’?’ whitespace ’(’ whitespace (item whitespace)* ’)’. Permitted in all specification style variables.

In particular, note that whitespace is not optional.

Table 8.2: EAPIs supporting SRC_URI arrows

EAPI | Supports SRC_URI arrows?
0 | No
1 | No
2 | Yes
3 | Yes
4 | Yes
5 | Yes

Table 8.3: EAPIs supporting REQUIRED_USE ?? groups

EAPI | Supports REQUIRED_USE ?? groups?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

#### 8.2.1 All-of Dependency Specifications

In an all-of group, all of the child elements must be matched.

#### 8.2.2 Use-conditional Dependency Specifications

In a use-conditional group, if the associated use flag is enabled (or disabled if it has an exclamation mark prefix), all of the child elements must be matched.

It is an error for a flag to be used if it is not included in IUSE_EFFECTIVE as described in section 11.1.1.

#### 8.2.3 Any-of Dependency Specifications

Any use-conditional group that is an immediate child of an any-of group, if not enabled (disabled for an exclamation mark prefixed use flag name), is not considered a member of the any-of group for match purposes.

In an any-of group, at least one immediate child element must be matched. A blocker is considered to be matched if its associated package dependency specification is not matched.

An empty any-of group counts as being matched.

#### 8.2.4 Exactly-one-of Dependency Specifications

Any use-conditional group that is an immediate child of an exactly-one-of group, if not enabled (disabled for an exclamation mark prefixed use flag name), is not considered a member of the exactly-one-of group for match purposes.

In an exactly-one-of group, exactly one immediate child element must be matched.

An empty exactly-one-of group counts as being matched.

#### 8.2.5 At-most-one-of Dependency Specifications

Any use-conditional group that is an immediate child of an at-most-one-of group, if not enabled (disabled for an exclamation mark prefixed use flag name), is not considered a member of the at-most-one-of group for match purposes.

In an at-most-one-of group, at most one immediate child element must be matched.

An empty at-most-one-of group counts as being matched.

#### 8.2.6 Package Dependency Specifications

A package dependency can be in one of the following base formats. A package manager must warn or error on non-compliant input.

- A simple category/package name.
- An operator, as described in section 8.2.6.1, followed immediately by category/package, followed by a hyphen, followed by a version specification.

In EAPIs shown in table 8.4 as supporting SLOT dependencies, either of the above formats may additionally be suffixed by a :slot restriction, as described in section 8.2.6.3. A package manager must warn or error if slot dependencies are used with an EAPI not supporting SLOT dependencies.

USE-DEPS

In EAPIs shown in table 8.5 as supporting 2-style or 4-style USE dependencies, a specification may additionally be suffixed by at most one 2-style or 4-style [use] restriction, as described in section 8.2.6.4. A package manager must warn or error if this feature is used with an EAPI not supporting use dependencies.

Note: Order is important. The slot restriction must come before use dependencies.

Table 8.4: Support for SLOT dependencies and sub-slots in EAPIs

EAPI | Supports SLOT dependencies? | Supports sub-slots?
0 | No | No
1 | Named only | No
2 | Named only | No
3 | Named only | No
4 | Named only | No
5 | Named and operator | Yes

Table 8.5: EAPIs supporting USE dependencies

EAPI | Supports USE dependencies?
0 | No
1 | No
2 | 2-style
3 | 2-style
4 | 4-style
5 | 4-style

##### 8.2.6.1 Operators

The following operators are available:

<
  Strictly less than the specified version.
<=
  Less than or equal to the specified version.
=
  Exactly equal to the specified version. Special exception: if the version specified has an asterisk immediately following it, a string prefix comparison is used instead. When an asterisk is used, the specification must remain valid if the asterisk were removed. (An asterisk used with any other operator is illegal.)
~
  Equal to the specified version, except the revision part of the matching package may be greater than the revision part of the specified version (-r0 is assumed if no revision is explicitly stated).
>=
  Greater than or equal to the specified version.
>
  Strictly greater than the specified version.

##### 8.2.6.2 Block Operator

If the specification is prefixed with one or two exclamation marks, the named dependency is a block rather than a requirement—that is to say, the specified package must not be installed, with the following exceptions:

- Blocks on a package provided exclusively by the ebuild do not count.
- Weak blocks on the package version of the ebuild itself do not count.

BANG-STRENGTH

There are two strengths of block: weak and strong. A weak block may be ignored by the package manager, so long as any blocked package will be uninstalled later on. A strong block must not be ignored. The mapping from one or two exclamation marks to strength is described in table 8.6.

Table 8.6: Exclamation mark strengths for EAPIs

EAPI | ! | !!
0 | Unspecified | Forbidden
1 | Unspecified | Forbidden
2 | Weak | Strong
3 | Weak | Strong
4 | Weak | Strong
5 | Weak | Strong

##### 8.2.6.3 Slot Dependencies

SLOT-DEPS

A named slot dependency consists of a colon followed by a slot name. A specification with a named slot dependency matches only if the slot of the matched package is equal to the slot specified. If the slot of the package to match cannot be determined (e. g. because it is not a supported EAPI), the match is treated as unsuccessful.

SUB-SLOT

In EAPIs shown in table 8.4 as supporting sub-slots, a slot dependency may contain an optional sub-slot part that follows the regular slot and is delimited by a / character.

SLOT-OPERATOR-DEPS

An operator slot dependency consists of a colon followed by one of the following operators:

*
  Indicates that any slot value is acceptable. In addition, for runtime dependencies, indicates that the package will not break if the matched package is uninstalled and replaced by a different matching package in a different slot.
=
  Indicates that any slot value is acceptable. In addition, for runtime dependencies, indicates that the package will break unless a matching package with slot and sub-slot equal to the slot and sub-slot of the best installed version at the time the package was installed is available.
slot=
  Indicates that only a specific slot value is acceptable, and otherwise behaves identically to the plain equals slot operator.

To implement the equals slot operator, the package manager will need to store the slot/sub-slot pair of the best installed version of the matching package. This syntax is only for package manager use and must not be used by ebuilds. The package manager may do this by inserting the appropriate slot/sub-slot pair between the colon and equals sign when saving the package’s dependencies. The sub-slot part must not be omitted here (when the SLOT variable omits the sub-slot part, the package is considered to have an implicit sub-slot which is equal to the regular slot).

##### 8.2.6.4 2-Style and 4-Style Use Dependencies

A 2-style or 4-style use dependency consists of one of the following:

[opt]
  The flag must be enabled.
[opt=]
  The flag must be enabled if the flag is enabled for the package with the dependency, or disabled otherwise.
[!opt=]
  The flag must be disabled if the flag is enabled for the package with the dependency, or enabled otherwise.
[opt?]
  The flag must be enabled if the flag is enabled for the package with the dependency.
[!opt?]
  The flag must be disabled if the use flag is disabled for the package with the dependency.
[-opt]
  The flag must be disabled.

Multiple requirements may be combined using commas, e. g. [first,-second,third?].

When multiple requirements are specified, all must match for a successful match.

USE-DEP-DEFAULTS

In a 4-style use dependency, the flag name may immediately be followed by a default specified by either (+) or (-). The former indicates that, when applying the use dependency to a package that does not have the flag in question in IUSE_REFERENCEABLE, the package manager shall behave as if the flag were present and enabled; the latter, present and disabled.

Unless a 4-style default is specified, it is an error for a use dependency to be applied to an ebuild which does not have the flag in question in IUSE_REFERENCEABLE.

Note: By extension of the above, a default that could reference an ebuild using an EAPI not supporting profile IUSE injections cannot rely upon any particular behaviour for flags that would not have to be part of IUSE.

It is an error for an ebuild to use a conditional use dependency when that ebuild does not have the flag in IUSE_EFFECTIVE.

#### 8.2.7 Use State Constraints

REQUIRED_USE contains a list of assertions that must be met by the configuration of USE flags to be valid for this ebuild. In order to be matched, a USE flag in a terminal element must be enabled (or disabled if it has an exclamation mark prefix).

If the package manager encounters a package version where REQUIRED_USE assertions are not met, it must treat this package version as if it was masked. No phase functions must be called.

It is an error for a flag to be used if it is not included in IUSE_EFFECTIVE.

#### 8.2.8 Restrict

The following tokens are permitted inside RESTRICT:

mirror
  The package’s SRC_URI entries may not be mirrored, and mirrors should not be checked when fetching.
fetch
  The package’s SRC_URI entries may not be downloaded automatically. If entries are not available, pkg_nofetch is called.
strip
  No stripping of debug symbols from files to be installed may be performed.
userpriv
  The package manager may not drop root privileges when building the package.
test
  The src_test phase must not be run.
sandbox
  The sandbox tool must not be used when building the package.

Package managers may recognise other tokens, but ebuilds may not rely upon them being supported.

#### 8.2.9 Properties

The following tokens are permitted inside PROPERTIES:

interactive
  The package may require interaction with the user via the tty.

Ebuilds may not rely upon any token being supported.

#### 8.2.10 SRC_URI

All filename components that are enabled (i. e. not inside a use-conditional block that is not matched) in SRC_URI must be available in the DISTDIR directory. In addition, these components are used to make the A and AA variables.

If a component contains a full URI with protocol, that download location must be used. Package managers may also consult mirrors for their files.

The special mirror:// protocol must be supported. See section 4.4.2 for mirror details.

If a simple filename rather than a full URI is provided, the package manager can only use mirrors to download the file.

The RESTRICT metadata key can be used to impose additional restrictions upon downloading—see section 8.2.8 for details.

SRC-URI-ARROWS

In EAPIs supporting arrows, if an arrow is used, the filename used when saving to DISTDIR shall instead be the name on the right of the arrow. When consulting mirrors (except for those explicitly listed on the left of the arrow, if mirror:// is used), the filename to the right of the arrow shall be requested instead of the filename in the URI.

## Chapter 9
Ebuild-defined Functions

### 9.1 List of Functions

The following is a list of functions that an ebuild, or eclass, may define, and which will be called by the package manager as part of the build and/or install process. In all cases the package manager must provide a default implementation of these functions; unless otherwise stated this must be a no-op. Most functions must assume only that they have write access to the package’s working directory (the WORKDIR environment variable; see section 11.1), and the temporary directory T; exceptions are noted below. All functions may assume that they have read access to all system libraries, binaries and configuration files that are accessible to normal users.

The environment for functions run outside of the build sequence (that is, pkg_config, pkg_info, pkg_prerm and pkg_postrm) must be the environment used for the build of the package, not the current configuration.

Ebuilds must not call nor assume the existence of any phase functions.

#### 9.1.1 Initial Working Directories

Some functions may assume that their initial working directory is set to a particular location; these are noted below. If no initial working directory is mandated, it may be set to anything and the ebuild must not rely upon a particular location for it. The ebuild may assume that the initial working directory for any phase is a trusted location that may only be written to by a privileged user and group.

S-WORKDIR-FALLBACK

Some functions are described as having an initial working directory of S with an error or fallback to WORKDIR. For EAPIs listed in table 9.1 as having the fallback, this means that if S is not a directory before the start of the phase function, the initial working directory shall be WORKDIR instead. For EAPIs where it is a conditional error, if S is not a directory before the start of the phase function, it is a fatal error, unless all of the following conditions are true, in which case the fallback to WORKDIR is used:

- The A variable contains no items.
- The phase function in question is not in DEFINED_PHASES.
- None of the phase functions unpack, prepare, configure, compile or install, if supported by the EAPI in question and occurring prior to the phase about to be executed, are in DEFINED_PHASES.

Table 9.1: EAPIs with S to WORKDIR fallbacks

EAPI | Fallback to WORKDIR permitted?
0 | Always
1 | Always
2 | Always
3 | Always
4 | Conditional error
5 | Conditional error

#### 9.1.2 pkg_pretend

PKG-PRETEND

The pkg_pretend function is only called for EAPIs listed in table 9.2 as supporting it.

The pkg_pretend function may be used to carry out sanity checks early on in the install process. For example, if an ebuild requires a particular kernel configuration, it may perform that check in pkg_pretend and call eerror and then die with appropriate messages if the requirement is not met.

pkg_pretend is run separately from the main phase function sequence, and does not participate in any kind of environment saving. There is no guarantee that any of an ebuild’s dependencies will be met at this stage, and no guarantee that the system state will not have changed substantially before the next phase is executed.

pkg_pretend must not write to the filesystem.

Table 9.2: EAPIs supporting pkg_pretend

EAPI | Supports pkg_pretend?
0 | No
1 | No
2 | No
3 | No
4 | Yes
5 | Yes

#### 9.1.3 pkg_setup

The pkg_setup function sets up the ebuild’s environment for all following functions, before the build process starts. Further, it checks whether any necessary prerequisites not covered by the package manager, e. g. that certain kernel configuration options are fulfilled.

pkg_setup must be run with full filesystem permissions, including the ability to add new users and/or groups to the system.

#### 9.1.4 src_unpack

SRC-UNPACK

The src_unpack function extracts all of the package’s sources. In EAPIs lacking src_prepare, it may also apply patches and set up the package’s build system for further use.

The initial working directory must be WORKDIR, and the default implementation used when the ebuild lacks the src_unpack function shall behave as:

src_unpack() {
if [[ -n ${A} ]]; then
unpack ${A}
fi
}

#### 9.1.5 src_prepare

SRC-PREPARE

The src_prepare function is only called for EAPIs listed in table 9.3 as supporting it.

The src_prepare function can be used for post-unpack source preparation. The default implementation does nothing.

The initial working directory is S, with an error or fallback to WORKDIR as discussed in section 9.1.1.

Table 9.3: EAPIs supporting src_prepare

EAPI | Supports src_prepare?
0 | No
1 | No
2 | Yes
3 | Yes
4 | Yes
5 | Yes

#### 9.1.6 src_configure

SRC-CONFIGURE

The src_configure function is only called for EAPIs listed in table 9.4 as supporting it.

The initial working directory is S, with an error or fallback to WORKDIR as discussed in section 9.1.1.

The src_configure function configures the package’s build environment. The default implementation used when the ebuild lacks the src_configure function shall behave as:

src_configure() {
if [[ -x ${ECONF_SOURCE:-.}/configure ]]; then
econf
fi
}

Table 9.4: EAPIs supporting src_configure

EAPI | Supports src_configure?
0 | No
1 | No
2 | Yes
3 | Yes
4 | Yes
5 | Yes

#### 9.1.7 src_compile

SRC-COMPILE

The src_compile function configures the package’s build environment in EAPIs lacking src_configure, and builds the package in all EAPIs.

The initial working directory is S, with an error or fallback to WORKDIR as discussed in section 9.1.1.

SRC-COMPILE-0

For EAPIs listed in table 9.5 as using format 0, the default implementation used when the ebuild lacks the src_compile function shall behave as:

src_compile() {
if [[ -x ./configure ]]; then
econf
fi
if [[ -f Makefile ]] || [[ -f GNUmakefile ]] || [[ -f makefile ]]; then
emake || die "emake failed"
fi
}

SRC-COMPILE-1

For EAPIs listed in table 9.5 as using format 1, the default implementation used when the ebuild lacks the src_compile function shall behave as:

src_compile() {
if [[ -x ${ECONF_SOURCE:-.}/configure ]]; then
econf
fi
if [[ -f Makefile ]] || [[ -f GNUmakefile ]] || [[ -f makefile ]]; then
emake || die "emake failed"
fi
}

SRC-COMPILE-2

For EAPIs listed in table 9.5 as using format 2, the default implementation used when the ebuild lacks the src_compile function shall behave as:

src_compile() {
if [[ -f Makefile ]] || [[ -f GNUmakefile ]] || [[ -f makefile ]]; then
emake || die "emake failed"
fi
}

Table 9.5: src_compile behaviour for EAPIs

EAPI | Format
0 | 0
1 | 1
2 | 2
3 | 2
4 | 2
5 | 2

#### 9.1.8 src_test

The src_test function runs unit tests for the newly built but not yet installed package as provided.

The initial working directory must be S if that exists, falling back to WORKDIR otherwise. The default implementation used when the ebuild lacks the src_test function must, if tests are enabled, run emake check if and only if such a target is available, or if not run emake test if and only if such a target is available. In both cases, if emake returns non-zero the build must be aborted.

PARALLEL-TESTS

For EAPIs listed in table 9.6 as not supporting parallel tests, the emake command must be called with option -j1.

The src_test function may be disabled by RESTRICT. See section 8.2.8. It may be disabled by user too, using a PM-specific mechanism.

Table 9.6: src_test behaviour for EAPIs

EAPI | Supports parallel tests?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

#### 9.1.9 src_install

SRC-INSTALL

The src_install function installs the package’s content to a directory specified in D.

The initial working directory is S, with an error or fallback to WORKDIR as discussed in section 9.1.1.

SRC-INSTALL-4

For EAPIs listed in table 9.7 as using format 4, the default implementation used when the ebuild lacks the src_install function shall behave as:

src_install() {
if [[ -f Makefile ]] || [[ -f GNUmakefile ]] || [[ -f makefile ]]; then
emake DESTDIR="${D}" install
fi
if ! declare -p DOCS >/dev/null 2>&1 ; then
local d
for d in README* ChangeLog AUTHORS NEWS TODO CHANGES \
THANKS BUGS FAQ CREDITS CHANGELOG ; do
[[ -s "${d}" ]] && dodoc "${d}"
done
elif declare -p DOCS | grep -q ’^declare -a ’ ; then
dodoc "${DOCS[@]}"
else
dodoc ${DOCS}
fi
}

For other EAPIs, the default implementation used when the ebuild lacks the src_install function is a no-op.

Table 9.7: src_install behaviour for EAPIs

EAPI | Format
0 | no-op
1 | no-op
2 | no-op
3 | no-op
4 | 4
5 | 4

#### 9.1.10 pkg_preinst

The pkg_preinst function performs any special tasks that are required immediately before merging the package to the live filesystem. It must not write outside of the directories specified by the ROOT and D environment variables.

pkg_preinst must be run with full access to all files and directories below that specified by the ROOT and D environment variables.

#### 9.1.11 pkg_postinst

The pkg_postinst function performs any special tasks that are required immediately after merging the package to the live filesystem. It must not write outside of the directory specified in the ROOT environment variable.

pkg_postinst, like, pkg_preinst, must be run with full access to all files and directories below that specified by the ROOT environment variable.

#### 9.1.12 pkg_prerm

The pkg_prerm function performs any special tasks that are required immediately before unmerging the package from the live filesystem. It must not write outside of the directory specified by the ROOT environment variable.

pkg_prerm must be run with full access to all files and directories below that specified by the ROOT environment variable.

#### 9.1.13 pkg_postrm

The pkg_postrm function performs any special tasks that are required immediately after unmerging the package from the live filesystem. It must not write outside of the directory specified by the ROOT environment variable.

pkg_postrm must be run with full access to all files and directories below that specified by the ROOT environment variable.

#### 9.1.14 pkg_config

The pkg_config function performs any custom steps required to configure a package after it has been fully installed. It is the only ebuild function which may be interactive and prompt for user input.

pkg_config must be run with full access to all files and directories inside of ROOT.

#### 9.1.15 pkg_info

PKG-INFO

The pkg_info function may be called by the package manager when displaying information about an installed package. In EAPIs listed in table 9.8 as supporting pkg_info on non-installed packages, it may also be called by the package manager when displaying information about a non-installed package. In this case, ebuild authors should note that dependencies may not be installed.

pkg_info must not write to the filesystem.

Table 9.8: EAPIs supporting pkg_info on non-installed packages

EAPI | Supports pkg_info on non-installed packages?
0 | No
1 | No
2 | No
3 | No
4 | Yes
5 | Yes

#### 9.1.16 pkg_nofetch

The pkg_nofetch function is run when the fetch phase of an fetch-restricted ebuild is run, and the relevant source files are not available. It should direct the user to download all relevant source files from their respective locations, with notes concerning licensing if applicable.

pkg_nofetch must require no write access to any part of the filesystem.

#### 9.1.17 default_ Phase Functions

DEFAULT-PHASE-FUNCS

In EAPIs listed in table 9.9 as supporting default_ phase functions, a function named default_(phase) that behaves as the default implementation for that EAPI shall be defined when executing any ebuild phase listed in the table. Ebuilds must not call these functions except when in the phase in question.

Table 9.9: EAPIs supporting default_ phase functions

EAPI | Supports default_ functions in phases
0 | None
1 | None
2 | pkg_nofetch, src_unpack, src_prepare, src_configure, src_compile, src_test
3 | pkg_nofetch, src_unpack, src_prepare, src_configure, src_compile, src_test
4 | pkg_nofetch, src_unpack, src_prepare, src_configure, src_compile, src_install, src_test
5 | pkg_nofetch, src_unpack, src_prepare, src_configure, src_compile, src_install, src_test

### 9.2 Call Order

The call order for installing a package is:

- pkg_pretend (only for EAPIs listed in table 9.2), which is called outside of the normal call order process.
- pkg_setup
- src_unpack
- src_prepare (only for EAPIs listed in table 9.3)
- src_configure (only for EAPIs listed in table 9.4)
- src_compile
- src_test (except if RESTRICT=test or disabled by user)
- src_install
- pkg_preinst
- pkg_postinst

The call order for uninstalling a package is:

- pkg_prerm
- pkg_postrm

The call order for upgrading, downgrading or reinstalling a package is:

- pkg_pretend (only for EAPIs listed in table 9.2), which is called outside of the normal call order process.
- pkg_setup
- src_unpack
- src_prepare (only for EAPIs listed in table 9.3)
- src_configure (only for EAPIs listed in table 9.4)
- src_compile
- src_test (except if RESTRICT=test)
- src_install
- pkg_preinst
- pkg_prerm for the package being replaced
- pkg_postrm for the package being replaced
- pkg_postinst

Note: When up- or downgrading a package in EAPI 0 or 1, the last four phase functions can alternatively be called in the order pkg_preinst, pkg_postinst, pkg_prerm, pkg_postrm. This behaviour is deprecated.

The pkg_config, pkg_info and pkg_nofetch functions are not called in a normal sequence. The pkg_pretend function is called some unspecified time before a (possibly hypothetical) normal sequence.

For installing binary packages, the src phases are not called.

When building binary packages that are not to be installed locally, the pkg_preinst and pkg_postinst functions are not called.

## Chapter 10
Eclasses

Eclasses serve to store common code that is used by more than one ebuild, which greatly aids maintainability and reduces the tree size. However, due to metadata cache issues, care must be taken in their use. In format they are similar to an ebuild, and indeed are sourced as part of any ebuild using them. The interpreter is therefore the same, and the same requirements for being parseable hold.

Eclasses must be located in the eclass directory in the top level of the repository—see section 4.6. Each eclass is a single file named <name>.eclass, where <name> is the name of this eclass, used by inherit and EXPORT_FUNCTIONS among other places.

### 10.1 The inherit command

An ebuild wishing to make use of an eclass does so by using the inherit command in global scope. This will cause the eclass to be sourced as part of the ebuild—any function or variable definitions in the eclass will appear as part of the ebuild, with exceptions for certain metadata variables, as described below.

The inherit command takes one or more parameters, which must be the names of eclasses (excluding the .eclass suffix and the path). For each parameter, in order, the named eclass is sourced.

Eclasses may end up being sourced multiple times.

The inherit command must also ensure that:

- The ECLASS variable is set to the name of the current eclass, when sourcing that eclass.
- Once all inheriting has been done, the INHERITED metadata variable contains the name of every eclass used, separated by whitespace.

### 10.2 Eclass-defined Metadata Keys

The IUSE, REQUIRED_USE, DEPEND, RDEPEND and PDEPEND variables are handled specially when set by an eclass. They must be accumulated across eclasses, appending the value set by each eclass to the resulting value after the previous one is loaded. Then the eclass-defined value is appended to that defined by the ebuild. In the case of RDEPEND, this is done after the implicit RDEPEND rules in section 7.3.3 are applied.

### 10.3 EXPORT_FUNCTIONS

There is one command available in the eclass environment that is neither available nor meaningful in ebuilds—EXPORT_FUNCTIONS. This can be used to alias ebuild phase functions from the eclass so that an ebuild inherits a default definition whilst retaining the ability to override and call the eclass-defined version from it. The use of it is best illustrated by an example; this is given in listing 10.1 and is a snippet from a hypothetical foo.eclass.

Listing 10.1: EXPORT_FUNCTIONS example: foo.eclass
foo_src_compile()
{
econf --enable-gerbil \
$(use_enable fnord)
emake gerbil || die "Couldn’t make a gerbil"
emake || die "emake failed"
}
EXPORT_FUNCTIONS src_compile

This example defines an eclass src_compile function and uses EXPORT_FUNCTIONS to alias it. Then any ebuild that inherits foo.eclass will have a default src_compile defined, but should the author wish to override it he can access the function in foo.eclass by calling foo_src_compile.

EXPORT_FUNCTIONS must only be used on ebuild phase functions. The function that is aliased must be named eclassname_phasefunctionname, where eclassname is the name of the eclass.

## Chapter 11
The Ebuild Environment

### 11.1 Defined Variables

The package manager must define the following environment variables. Not all variables are meaningful in all phases; variables that are not meaningful in a given phase may be unset or set to any value. Ebuilds must not attempt to modify any of these variables, unless otherwise specified.

Because of their special meanings, these variables may not be preserved consistently across all phases as would normally happen due to environment saving (see 11.2). For example, EBUILD_PHASE is different for every phase, and ROOT may have changed between the various different pkg_* phases. Ebuilds must recalculate any variable they derive from an inconsistent variable.

Table 11.1: Defined variables
Variable | Legal in | Consistent? | Description
P | all | No1 | Package name and version, without the revision part. For example, vim-7.0.174.
PN | all | ditto | Package name, for example vim.
CATEGORY | all | ditto | The package’s category, for example app-editors.
PV | all | Yes | Package version, with no revision. For example 7.0.174.
PR | all | Yes | Package revision, or r0 if none exists.
PVR | all | Yes | Package version and revision (if any), for example 7.0.174 or 7.0.174-r1.
PF | all | Yes | Package name, version, and revision (if any), for example vim-7.0.174-r1.
A | src_* | Yes | All source files available for the package, whitespace separated with no leading or trailing whitespace, and in the order in which the item first appears in a matched component of SRC_URI. Does not include any that are disabled because of USE conditionals. The value is calculated from the base names of each element of the SRC_URI ebuild metadata variable.
AA2 | src_* | Yes | AA All source files that could be available for the package, including any that are disabled in A because of USE conditionals. The value is calculated from the base names of each element of the SRC_URI ebuild metadata variable. Only for EAPIs listed in table 11.3 as supporting AA.
FILESDIR | src_*3 | No | The full path to the package’s files directory, used for small support files or patches. See section 4.3. May or may not exist; if a repository provides no support files for the package in question then an ebuild must be prepared for the situation where FILESDIR points to a non-existent directory.
PORTDIR | ditto | No | The full path to the master repository’s base directory.
DISTDIR | ditto | No | The full path to the directory in which the files in the A variable are stored.
ECLASSDIR | ditto | No | The full path to the master repository’s eclass directory.
ROOT | pkg_* | No | The absolute path to the root directory into which the package is to be merged. Phases which run with full filesystem access must not touch any files outside of the directory given in ROOT. Also of note is that in a cross-compiling environment, binaries inside of ROOT will not be executable on the build machine, so ebuilds must not call them. ROOT must be non-empty and end in a trailing slash.
EROOT | pkg_* | No | Contains the path ${ROOT%/}${EPREFIX}/ for convenience. See also the EPREFIX variable. Only for EAPIs listed in table 11.4 as supporting EROOT.
T | All | Partially4 | The full path to a temporary directory for use by the ebuild.
TMPDIR | All | Ditto | Must be set to the location of a usable temporary directory, for any applications called by an ebuild. Must not be used by ebuilds directly; see T above.
HOME | All | Ditto | The full path to an appropriate temporary directory for use by any programs invoked by the ebuild that may read or modify the home directory.
EPREFIX | All | Yes | The normalised offset-prefix path of an offset installation. When EPREFIX is not set in the calling environment, EPREFIX defaults to the built-in offset-prefix that was set during installation of the package manager. When a different EPREFIX value than the built-in value is set in the calling environment, a cross-prefix build is performed where using the existing utilities, a package is built for the given EPREFIX, akin to ROOT. See also 11.1.3. Only for EAPIs listed in table 11.4 as supporting EPREFIX.
D | src_install | No | Contains the full path to the image directory into which the package should be installed. Must be non-empty and end in a trailing slash.
D (continued) | pkg_preinst, pkg_postinst | Yes | Contains the full path to the image that is about to be or has just been merged. Must be non-empty and end in a trailing slash.
ED | src_ install, pkg_ preinst, pkg_ postinst | See D | Contains the path ${D%/}${EPREFIX}/ for convenience. See also the EPREFIX variable. Only for EAPIs listed in table 11.4 as supporting ED.
INSDESTTREE | src_install | No | Controls the location where doins installs things.
USE | All | Yes | A whitespace-delimited list of all active USE flags for this ebuild. See section 11.1.1 for details.
EBUILD_PHASE | All | No | Takes one of the values config, setup, nofetch, unpack, prepare, configure, compile, test, install, preinst, postinst, prerm, postrm, info, pretend according to the top level ebuild function that was executed by the package manager. May be unset or any single word that is not any of the above when the ebuild is being sourced for other (e. g. metadata or QA) purposes.
EBUILD_PHASE_FUNC | All | No | EBUILD-PHASE-FUNC Takes one of the values pkg_config, pkg_setup, pkg_nofetch, src_unpack, src_prepare, src_configure, src_compile, src_test, src_install, pkg_ preinst, pkg_postinst, pkg_prerm, pkg_ postrm, pkg_info, pkg_pretend according to the top level ebuild function that was executed by the package manager. May be unset or any single word that is not any of the above when the ebuild is being sourced for other (e. g. metadata or QA) purposes. Only for EAPIs listed in table 11.2 as supporting EBUILD_PHASE_FUNC.
WORKDIR | src_*, global scope | Yes | The full path to the ebuild’s working directory, in which all build data should be contained.
S | src_* | Yes | The full path to the temporary build directory, used by src_compile, src_install etc. Defaults to ${WORKDIR}/${P}. May be modified by ebuilds. If S is assigned in the global scope of an ebuild, then the restrictions of section 11.2 for global variables apply.
KV | All | Yes | KV The version of the running kernel at the time the ebuild was first executed, as returned by the uname -r command or equivalent. May be modified by ebuilds. Only for EAPIs listed in table 11.3 as supporting KV.
MERGE_TYPE | pkg_* | No | MERGE-TYPE The type of package that is being merged. Possible values are: source if building and installing a package from source, binary if installing a binary package, and buildonly if building a binary package without installing it. Only for EAPIs listed in table 11.2 as supporting MERGE_TYPE.
REPLACING_VERSIONS | pkg_* (see text) | Yes | A whitespace-separated list of versions of this package (including revision, if specified) that are being replaced (uninstalled or overwritten) as a result of this install. See section 11.1.2. Only for EAPIs listed in table 11.2 as supporting REPLACING_VERSIONS.
REPLACED_BY_VERSION | pkg_prerm, pkg_postrm | Yes | The single version of this package (including revision, if specified) that is replacing us, if we are being uninstalled as part of an install, or an empty string otherwise. See section 11.1.2. Only for EAPIs listed in table 11.2 as supporting REPLACED_BY_VERSION.

Table 11.2: EAPIs supporting various added env variables

EAPI | MERGE_TYPE? | REPLACING_VERSIONS? | REPLACED_BY_VERSION? | EBUILD_PHASE_FUNC?
0 | No | No | No | No
1 | No | No | No | No
2 | No | No | No | No
3 | No | No | No | No
4 | Yes | Yes | Yes | No
5 | Yes | Yes | Yes | Yes

Table 11.3: EAPIs supporting various removed env variables

EAPI | AA? | KV?
0 | Yes | Yes
1 | Yes | Yes
2 | Yes | Yes
3 | Yes | Yes
4 | No | No
5 | No | No

Table 11.4: EAPIs supporting offset-prefix env variables

EAPI | EPREFIX? | EROOT? | ED?
0 | No | No | No
1 | No | No | No
2 | No | No | No
3 | Yes | Yes | Yes
4 | Yes | Yes | Yes
5 | Yes | Yes | Yes

Except where otherwise noted, all variables set in the active profiles’ make.defaults files must be exported to the ebuild environment. CHOST, CBUILD and CTARGET, if not set by profiles, must contain either an appropriate machine tuple (the definition of appropriate is beyond the scope of this specification) or be unset.

PATH must be initialized by the package manager to a “usable” default. The exact value here is left up to interpretation, but it should include the equivalent “sbin” and “bin” and any package manager specific directories.

GZIP, BZIP, BZIP2, CDPATH, GREP_OPTIONS, GREP_COLOR and GLOBIGNORE must not be set.

#### 11.1.1 USE and IUSE Handling

This section discusses the handling of four variables:

IUSE
  is the variable calculated from the IUSE values defined in ebuilds and eclasses.
IUSE_REFERENCEABLE
  is a variable calculated from IUSE and a variety of other sources described below. It is purely a conceptual variable; it is not exported to the ebuild environment. Values in IUSE_REFERENCEABLE may legally be used in queries from other packages about an ebuild’s state (for example, for use dependencies).
IUSE_EFFECTIVE
  is another conceptual, unexported variable. Values in IUSE_ EFFECTIVE are those which an ebuild may legally use in queries about itself (for example, for the use function, and for use in dependency specification conditional blocks).
USE
  is a variable calculated by the package manager and exported to the ebuild environment.

In all cases, the values of IUSE_REFERENCEABLE and IUSE_EFFECTIVE are undefined during metadata generation.

For EAPIs listed in table 5.2 as not supporting profile defined IUSE injection, IUSE_REFERENCEABLE is equal to the calculated IUSE value. For EAPIs where profile defined IUSE injection is supported, IUSE_REFERENCEABLE is equal to IUSE_EFFECTIVE.

For EAPIs listed in table 5.2 as not supporting profile defined IUSE injection, IUSE_EFFECTIVE contains the following values:

- All values in the calculated IUSE value.
- All possible values for the ARCH variable.
- All legal use flag names whose name starts with the lowercase equivalent of any value in the profile USE_EXPAND variable followed by an underscore.

PROFILE-IUSE-INJECT

For EAPIs listed in table 5.2 as supporting profile defined IUSE injection, IUSE_EFFECTIVE contains the following values:

- All values in the calculated IUSE value.
- All values in the profile IUSE_IMPLICIT variable.
- All values in the profile variable named USE_EXPAND_VALUES_${v}, where ${v} is any value in the intersection of the profile USE_EXPAND_UNPREFIXED and USE_EXPAND_ IMPLICIT variables.
- All values for ${lower_v}_${x}, where ${x} is all values in the profile variable named USE_EXPAND_VALUES_${v}, where ${v} is any value in the intersection of the profile USE_EXPAND and USE_EXPAND_IMPLICIT variables and ${lower_v} is the lowercase equivalent of ${v}.

The USE variable is set by the package manager. For each value in IUSE_EFFECTIVE, USE shall contain that value if the flag is to be enabled for the ebuild in question, and shall not contain that value if it is to be disabled. In EAPIs listed in table 5.2 as not supporting profile defined IUSE injection, USE may contain other flag names that are not relevant for the ebuild.

For EAPIs listed in table 5.2 as supporting profile defined IUSE injection, the variables named in USE_EXPAND and USE_EXPAND_UNPREFIXED shall have their profile-provided values reduced to contain only those values that are present in IUSE_EFFECTIVE.

For EAPIs listed in table 5.2 as supporting profile defined IUSE injection, the package manager must save the calculated value of IUSE_EFFECTIVE when installing a package. Details are beyond the scope of this specification.

#### 11.1.2 REPLACING_VERSIONS and REPLACED_BY_VERSION

REPLACE-VERSION-VARS

In EAPIs listed in table 11.2 as supporting it, the REPLACING_VERSIONS variable shall be defined in pkg_preinst and pkg_postinst. In addition, it may be defined in pkg_pretend and pkg_setup, although ebuild authors should take care to handle binary package creation and installation correctly when using it in these phases.

REPLACING_VERSIONS is a list, not a single optional value, to handle pathological cases such as installing foo-2:2 to replace foo-2:1 and foo-3:2.

In EAPIs listed in table 11.2 as supporting it, the REPLACED_BY_VERSION variable shall be defined in pkg_prerm and pkg_postrm. It shall contain at most one value.

#### 11.1.3 Offset-prefix variables EPREFIX, EROOT and ED

Table 11.5: EAPIs supporting offset-prefix

EAPI | Supports offset-prefix?
0 | No
1 | No
2 | No
3 | Yes
4 | Yes
5 | Yes

OFFSET-PREFIX-VARS

Table 11.5 lists the EAPIs which support offset-prefix installations. This support was initially added in EAPI 3, in the form of three extra variables. Two of these, EROOT and ED, are convenience variables using the variable EPREFIX. In EAPIs that do not support an offset-prefix, the installation offset is hardwired to /usr. In offset-prefix supporting EAPIs the installation offset is set as ${EPREFIX}/usr and hence can be adjusted using the variable EPREFIX. Note that the behaviour of offset-prefix aware and agnostic is the same when EPREFIX is set to the empty string in offset-prefix aware EAPIs. The latter do have the variables ED and EROOT properly set, though.

### 11.2 The state of variables between functions

Exported and default scope variables are saved between functions. A non-local variable set in a function earlier in the call sequence must have its value preserved for later functions, including functions executed as part of a later uninstall.

Note: pkg_pretend is not part of the normal call sequence, and does not take part in environment saving.

Variables that were exported must remain exported in later functions; variables with default visibility may retain default visibility or be exported.

Variables with special meanings to the package manager are excluded from this rule.

Global variables must only contain invariant values (see 7.1). If a global variable’s value is invariant, it may have the value that would be generated at any given point in the build sequence.

This is demonstrated by code listing 11.1.

Listing 11.1: Environment state between functions
GLOBAL_VARIABLE="a"
src_compile()
{
GLOBAL_VARIABLE="b"
DEFAULT_VARIABLE="c"
export EXPORTED_VARIABLE="d"
local LOCAL_VARIABLE="e"
}
src_install(){
[[ ${GLOBAL_VARIABLE} == "a" ]] \
|| [[ ${GLOBAL_VARIABLE} == "b" ]] \
|| die "broken env saving for globals"
[[ ${DEFAULT_VARIABLE} == "c" ]] \
|| die "broken env saving for default"
[[ ${EXPORTED_VARIABLE} == "d" ]] \
|| die "broken env saving for exported"
[[ $(printenv EXPORTED_VARIABLE ) == "d" ]] \
|| die "broken env saving for exported"
[[ -z ${LOCAL_VARIABLE} ]] \
|| die "broken env saving for locals"
}

### 11.3 Available commands

This section documents the commands available to an ebuild. Unless otherwise specified, they may be aliases, shell functions, or executables in the ebuild’s PATH.

When an ebuild is being sourced for metadata querying rather than for a build (that is to say, when none of the src_ or pkg_ functions are to be called), no external command may be executed. The package manager may take steps to enforce this.

#### 11.3.1 System commands

Any ebuild not listed in the system set for the active profile(s) may assume the presence of every command that is always provided by the system set for that profile. However, it must target the lowest common denominator of all systems on which it might be installed—in most cases this means that the only packages that can be assumed to be present are those listed in the base profile or equivalent, which is inherited by all available profiles. If an ebuild requires any applications not provided by the system profile, or that are provided conditionally based on USE flags, appropriate dependencies must be used to ensure their presence.

##### 11.3.1.1 Guaranteed system commands

The following commands must always be available in the ebuild environment:

- All builtin commands in GNU bash, version 3.25 .
- sed must be available, and must support all forms of invocations valid for GNU sed version 4 or later.
- patch must be available, and must support all inputs valid for GNU patch.

- GNU-FIND find and xargs must be available, and must support all forms of invocations valid for GNU findutils version 4.4 or later. Only for EAPIs listed in table 11.6 as requiring GNU find.

Table 11.6: find implementation for EAPIs

EAPI | GNU find?
0 | Undefined
1 | Undefined
2 | Undefined
3 | Undefined
4 | Undefined
5 | Yes

#### 11.3.2 Commands provided by package dependencies

In some cases a package’s build process will require the availability of executables not provided by the core system, a common example being autotools. The availability of commands provided by the particular types of dependencies is explained in section 8.1.

#### 11.3.3 Ebuild-specific Commands

The following commands will always be available in the ebuild environment, provided by the package manager. Except where otherwise noted, they may be internal (shell functions or aliases) or external commands available in PATH; where this is not specified, ebuilds may not rely upon either behaviour.

Unless otherwise noted, any output of these commands ends with a newline.

##### 11.3.3.1 Failure behaviour and related commands

DIE-ON-FAILURE

Where a command is listed as having EAPI dependent failure behaviour, a failure shall either result in a non-zero exit status or abort the build process, as determined by table 11.7.

The following commands affect this behaviour:

nonfatal

  NONFATAL Executes the remainder of its arguments as a command, preserving the exit status. If this results in a command being called that would normally abort the build process due to a failure (but not due to an explicit die or assert call), instead a non-zero exit status shall be returned. Only in EAPIs listed in table 11.7 as supporting nonfatal.

Table 11.7: EAPI Command Failure Behaviour

EAPI | Command failure behaviour | Supports nonfatal?
0 | Non-zero exit | No
1 | Non-zero exit | No
2 | Non-zero exit | No
3 | Non-zero exit | No
4 | Aborts | Yes
5 | Aborts | Yes

##### 11.3.3.2 Banned commands

BANNED-COMMANDS

Some commands are banned in some EAPIs. If a banned command is called, the package manager must abort the build process indicating an error.

Table 11.8: Banned commands

EAPI | Command banned?
| dohard | dosed
0 | No | No
1 | No | No
2 | No | No
3 | No | No
4 | Yes | Yes
5 | Yes | Yes

##### 11.3.3.3 Sandbox commands

These commands affect the behaviour of the sandbox. Each command takes a single directory as argument. Ebuilds must not run any of these commands once the current phase function has returned.

addread
  Add a directory to the permitted read list.
addwrite
  Add a directory to the permitted write list.
addpredict
  Add a directory to the predict list. Any write to a location in this list will be denied, but will not trigger access violation messages or abort the build process.
adddeny
  Add a directory to the deny list.

##### 11.3.3.4 Package manager query commands

These commands are used to extract information about the system. Ebuilds must not run any of these commands in parallel with any other package manager command. Ebuilds must not run any of these commands once the current phase function has returned.

HOST-ROOT-OPTION

In EAPIs listed in table 11.15 as supporting option --host-root, this flag as the first argument will cause the query to apply to the host root instead of ROOT.

has_version
  Takes exactly one package dependency specification as an argument. Returns true if a package matching the atom is installed in ROOT, and false otherwise.
best_version
  Takes exactly one package dependency specification as an argument. If a matching package is installed, prints the category, package name and version of the highest matching version; otherwise, prints an empty string. The exit code is unspecified.

##### 11.3.3.5 Output commands

These commands display messages to the user. Unless otherwise stated, the entire argument list is used as a message, with backslash-escaped characters interpreted as for the echo -e command of bash, notably \t for a horizontal tab, \n for a new line, and \\ for a literal backslash. Ebuilds must not run any of these commands once the current phase function has returned. Unless otherwise noted, output may be sent to stdout, stderr or some other appropriate facility.

einfo
  Displays an informational message.
einfon
  Displays an informational message without a trailing newline.
elog
  Displays an informational message of slightly higher importance. The package manager may choose to log elog messages by default where einfo messages are not, for example.
ewarn
  Displays a warning message. Must not go to stdout.
eerror
  Displays an error message. Must not go to stdout.
ebegin
  Displays an informational message. Should be used when beginning a possibly lengthy process, and followed by a call to eend.
eend
  Indicates that the process begun with an ebegin message has completed. Takes one fixed argument, which is a numeric return code, and an optional message in all subsequent arguments. If the first argument is 0, prints a success indicator; otherwise, prints the message followed by a failure indicator. Returns its first argument as exit status.

##### 11.3.3.6 Error commands

These commands are used when an error is detected that will prevent the build process from completing. Ebuilds must not run any of these commands once the current phase function has returned.

die
  Displays a failure message provided in its first and only argument, and then aborts the build process. die is not guaranteed to work correctly if called from a subshell environment.
assert
  Checks the value of the shell’s pipe status variable, and if any component is non-zero (indicating failure), calls die with its first argument as a failure message.

##### 11.3.3.7 Build commands

These commands are used during the src_compile and src_install phases to run the package’s build commands. Ebuilds must not run any of these commands once the current phase function has returned.

econf
  Calls the program’s ./configure script. This is designed to work with GNU Autoconf-generated scripts. Any additional parameters passed to econf are passed directly to ./configure. econf will look in the current working directory for a configure script unless the ECONF_SOURCE environment variable is set, in which case it is taken to be the directory containing it. econf must pass the following options to the configure script:

  ECONF-OPTIONS

  - --prefix must default to ${EPREFIX}/usr unless overridden by econf’s caller.
  - --mandir must be ${EPREFIX}/usr/share/man
  - --infodir must be ${EPREFIX}/usr/share/info
  - --datadir must be ${EPREFIX}/usr/share
  - --sysconfdir must be ${EPREFIX}/etc
  - --localstatedir must be ${EPREFIX}/var/lib
  - --host must be the value of the CHOST environment variable.
  - --libdir must be set according to Algorithm 9.
  - --disable-dependency-tracking, if the EAPI is listed in table 11.9 as using it. This option will only be passed if the string disable-dependency-tracking occurs in the output of configure --help.
  - --disable-silent-rules, if the EAPI is listed in table 11.9 as using it. This option will only be passed if the string disable-silent-rules occurs in the output of configure --help.

  Table 11.9: Extra econf arguments for EAPIs

  EAPI | --disable-dependency-tracking? | --disable-silent-rules?
  0 | No | No
  1 | No | No
  2 | No | No
  3 | No | No
  4 | Yes | No
  5 | Yes | Yes

  Note that the ${EPREFIX} component represents the same offset-prefix as described in Table 11.1. It facilitates offset-prefix installations which is supported by EAPIs listed in Table 11.4. When no offset-prefix installation is in effect, EPREFIX becomes the empty string, making the behaviour of econf equal for both offset-prefix supporting and agnostic EAPIs.

  econf must be implemented internally—that is, as a bash function and not an external script. Should any portion of it fail, it must abort the build using die, unless run using nonfatal, in which case it must return non-zero exit status.

  Algorithm 9: econf --libdir logic
  1: let prefix=${EPREFIX}/usr
  2: if the caller specified --prefix=$p then
  3: let prefix=$p
  4: end if
  5: let libdir=
  6: if the ABI environment variable is set then
  7: let libvar=LIBDIR_$ABI
  8: if the environment variable named by libvar is set then
  9: let libdir=the value of the variable named by libvar
  10: end if
  11: end if
  12: if libdir is non-empty then
  13: pass --libdir=$prefix/$libdir to configure
  14: end if

emake
  Calls the $MAKE program, or GNU make if the MAKE variable is unset. Any arguments given are passed directly to the make command, as are the user’s chosen MAKEOPTS. Arguments given to emake override user configuration. See also section 11.3.1.1. emake must be an external program and cannot be a function or alias—it must be callable from e. g. xargs. Failure behaviour is EAPI dependent as per section 11.3.3.1.
einstall
  A shortcut for the command given in Listing 11.2. Any arguments given to einstall are passed verbatim to emake, as shown. Failure behaviour is EAPI dependent as per section 11.3.3.1.

  The variable ED is defined as in Table 11.1 and depends on the use of an offset-prefix. When such offset-prefix is absent, ED is equivalent to D. ED is always available in EAPIs that support offset-prefix installations as listed in Table 11.4, hence EAPIs lacking offset-prefix support should use D instead of ED in the command given in Listing 11.2. Variable libdir is an auxiliary local variable whose value is determined by Algorithm 10.

  Listing 11.2: einstall command
  emake \
  prefix="${ED}"/usr \
  datadir="${ED}"/usr/share \
  mandir="${ED}"/usr/share/man \
  infodir="${ED}"/usr/share/info \
  libdir="${ED}"/usr/${libdir} \
  localstatedir="${ED}"/var/lib \
  sysconfdir="${ED}"/etc \
  -j1 \
  "$@" \
  install

##### 11.3.3.8 Installation commands

These commands are used to install files into the staging area, in cases where the package’s make install target cannot be used or does not install all needed files. Except where otherwise stated, all filenames created or modified are relative to the staging directory including the offset-prefix ED in offset-prefix aware EAPIs, or just the staging directory D in offset-prefix agnostic EAPIs. These commands must all be external programs and not bash functions or aliases—that is, they must be callable from xargs. Ebuilds must not run any of these commands once the current phase function has returned.

dobin
  Installs the given files into DESTTREE/bin, where DESTTREE defaults to /usr. Gives the files mode 0755 and transfers file ownership to the superuser or its equivalent on the system or installation at hand. For instance on Gentoo Linux in a non-offset-prefix installation this ownership is root:root, while on an offset-prefix aware installation this may be joe:users. Failure behaviour is EAPI dependent as per section 11.3.3.1.
doconfd
  Installs the given config files into /etc/conf.d/, by default with file mode 0644. This can be overridden by setting INSOPTIONS with the insopts function. Failure behaviour is EAPI dependent as per section 11.3.3.1.
dodir
  Creates the given directories, by default with file mode 0755. This can be overridden by setting DIROPTIONS with the diropts function. Failure behaviour is EAPI dependent as per section 11.3.3.1.
dodoc

  DODOC Installs the given files into a subdirectory under /usr/share/doc/${PF}/ with file mode 0644. The subdirectory is set by the most recent call to docinto. If docinto has not yet been called, instead installs to the directory /usr/share/doc/${PF}/. For EAPIs listed in table 11.10 as supporting -r, if the first argument is -r, any subsequent arguments that are directories are installed recursively to the appropriate location; in any other case, it is an error for a directory to be specified. Failure behaviour is EAPI dependent as per section 11.3.3.1.

doenvd
  Installs the given environment files into /etc/env.d/, by default with file mode 0644. This can be overridden by setting INSOPTIONS with the insopts function. Failure behaviour is EAPI dependent as per section 11.3.3.1.
doexe
  Installs the given files into the directory specified by the most recent exeinto call, by default with file mode 0755. This can be overridden by setting EXEOPTIONS with the exeopts function. If exeinto has not yet been called, behaviour is undefined. Failure behaviour is EAPI dependent as per section 11.3.3.1.
dohard
  Takes two parameters. Creates a hardlink from the second to the first. In EAPIs listed in table 11.8, this command is banned as per section 11.3.3.2.
doheader

  DOHEADER Installs the given header files into /usr/include/, by default with file mode 0644. This can be overridden by setting INSOPTIONS with the insopts function. If the first argument is -r, then operates recursively, descending into any directories given. Only available in EAPIs listed in table 11.11 as supporting doheader. Failure behaviour is EAPI dependent as per section 11.3.3.1.

dohtml
  Installs the given HTML files into a subdirectory under /usr/share/doc/$PF/. The subdirectory is html by default, but this can be overridden by setting the DOCDESTTREE variable with the docinto function. Files to be installed automatically are determined by extension and the default extensions are css, gif, htm, html, jpeg, jpg, js and png. These default extensions can be extended or reduced (see below). The options that can be passed to dohtml are as follows:
    -r — enables recursion into directories.
    -V — enables verbosity.
    -A — adds file type extensions to the default list.
    -a — sets file type extensions to only those specified.
    -f — list of files that are able to be installed.
    -x — list of directories that files will not be installed from (only used in conjunction with -r).
    -p — sets a document prefix for installed files, not to be confused with the global offset-prefix.

  Failure behaviour is EAPI dependent as per section 11.3.3.1.

  It is undefined whether a failure shall occur if -r is not specified and a directory is encountered. Ebuilds must not rely upon any particular behaviour.

doinfo
  Installs a GNU Info file into the /usr/share/info area with file mode 0644. Failure behaviour is EAPI dependent as per section 11.3.3.1.
doinitd
  Installs the given initscript files into /etc/init.d, by default with file mode 0755. This can be overridden by setting EXEOPTIONS with the exeopts function. Failure behaviour is EAPI dependent as per section 11.3.3.1.
doins

  DOINS Takes any number of files as arguments and installs them into INSDESTTREE, by default with file mode 0644. This can be overridden by setting INSOPTIONS with the insopts function. If the first argument is -r, then operates recursively, descending into any directories given. For EAPIs listed in table 11.12, doins must install symlinks as symlinks; for other EAPIs, behaviour is undefined if any symlink is encountered. Failure behaviour is EAPI dependent as per section 11.3.3.1.

dolib
  For each argument, installs it into the appropriate library subdirectory under DESTTREE, as determined by Algorithm 10. The file mode is 0644 by default. This can be overridden by setting LIBOPTIONS with the libopts function. Any symlinks are installed into the same directory as relative links to their original target. Failure behaviour is EAPI dependent as per section 11.3.3.1.
dolib.so
  As for dolib except each file is installed with mode 0755.
dolib.a
  As for dolib except each file is installed with mode 0644.

  Algorithm 10: Determining the library directory
  1: if CONF_LIBDIR_OVERRIDE is set in the environment then
  2: return CONF_LIBDIR_OVERRIDE
  3: end if
  4: if CONF_LIBDIR is set in the environment then
  5: let LIBDIR_default=CONF_LIBDIR
  6: else
  7: let LIBDIR_default=“lib”
  8: end if
  9: if ABI is set in the environment then
  10: let abi=ABI
  11: else if DEFAULT_ABI is set in the environment then
  12: let abi=DEFAULT_ABI
  13: else
  14: let abi=“default”
  15: end if
  16: return the value of LIBDIR_$abi

doman
  Installs a man page into the appropriate subdirectory of /usr/share/man depending upon its apparent section suffix (e. g. foo.1 goes to /usr/share/man/man1/foo.1) with file mode 0644.

  DOMAN-LANGS

  In EAPIs listed in table 11.13 as supporting language detection by filename, a man page with name of the form foo.lang.1 shall go to /usr/share/man/lang/man1/foo.1, where lang refers to a pair of lower-case ASCII letters optionally followed by an underscore and a pair of upper-case ASCII letters. Failure behaviour is EAPI dependent as per section 11.3.3.1.

  With option -i18n=lang, a man page shall be installed into an appropriate subdirectory of /usr/share/man/lang (e. g. /usr/share/man/lang/man1/foo.pl.1 would be the destination for foo.pl.1). The lang subdirectory level is skipped if lang is the empty string. In EAPIs specified by table 11.13, the -i18n option takes precedence over the language code in the filename.

domo
  Installs a .mo file with file mode 0644 into the appropriate subdirectory of DESTTREE/share/locale, generated by taking the basename of the file, removing the .* suffix, and appending /LC_MESSAGES. The name of the installed files is the package name with .mo appended. Failure behaviour is EAPI dependent as per section 11.3.3.1.
dosbin
  As dobin, but installs to DESTTREE/sbin.
dosym
  Creates a symbolic link named as for its second parameter, pointing to the first. If the directory containing the new link does not exist, creates it. Failure behaviour is EAPI dependent as per section 11.3.3.1.
fowners
  Acts as for chown, but takes paths relative to the image directory. Failure behaviour is EAPI dependent as per section 11.3.3.1.
fperms
  Acts as for chmod, but takes paths relative to the image directory. Failure behaviour is EAPI dependent as per section 11.3.3.1.
newbin

  NEWFOO-STDIN As for dobin, but takes two parameters. The first is the file to install; the second is the new filename under which it will be installed. In EAPIs specified by table 11.14, standard input is read when the first parameter is - (a hyphen). In this case, it is an error if standard input is a terminal.

newconfd
  As for doconfd, but takes two parameters as for newbin.
newdoc
  As above, for dodoc.
newenvd
  As above, for doenvd.
newexe
  As above, for doexe.
newheader
  As above, for doheader.
newinitd
  As above, for doinitd.
newins
  As above, for doins.
newlib.a
  As above, for dolib.a.
newlib.so
  As above, for dolib.so.
newman
  As above, for doman.
newsbin
  As above, for dosbin.
keepdir
  Creates a directory as for dodir, and an empty file whose name starts with .keep in that directory to ensure that the directory does not get removed by the package manager should it be empty at any point. Failure behaviour is EAPI dependent as per section 11.3.3.1.

Table 11.10: EAPIs supporting dodoc -r

EAPI | Supports dodoc -r?
0 | No
1 | No
2 | No
3 | No
4 | Yes
5 | Yes

Table 11.11: EAPIs supporting doheader and newheader

EAPI | Supports doheader and newheader?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

Table 11.12: EAPIs supporting symlinks for doins

EAPI | doins supports symlinks?
0 | No
1 | No
2 | No
3 | No
4 | Yes
5 | Yes

Table 11.13: doman language support options for EAPIs

EAPI | Language detection by filename? | Option -i18n takes precedence?
0 | No | Not applicable
1 | No | Not applicable
2 | Yes | No
3 | Yes | No
4 | Yes | Yes
5 | Yes | Yes

Table 11.14: EAPIs supporting stdin for new* commands

EAPI | new* can read from stdin?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

Table 11.15: EAPIs supporting --host-root for *_version commands

EAPI | *_version supports --host-root?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

##### 11.3.3.9 Commands affecting install destinations

The following commands are used to set the various destination trees, all relative to ${ED} in offset-prefix aware EAPIs and relative to ${D} in offset-prefix agnostic EAPIs, used by the above installation commands. They must be shell functions or aliases, due to the need to set variables read by the above commands. Ebuilds must not run any of these commands once the current phase function has returned.

into
  Sets the value of DESTTREE for future invocations of the above utilities. Creates the directory under ${ED} in offset-prefix aware EAPIs or under ${D} in offset-prefix agnostic EAPIs, using install -d with no additional options, if it does not already exist. Failure behaviour is EAPI dependent as per section 11.3.3.1.
insinto
  Sets the value of INSDESTTREE for future invocations of the above utilities. May create the directory, as specified for into.
exeinto
  Sets the install path for doexe and newexe. May create the directory, as specified for into.
docinto
  Sets the install subdirectory for dodoc et al. May create the directory, as specified for into.
insopts
  Sets the options passed by doins et al. to the install command.
diropts
  Sets the options passed by dodir et al. to the install command.
exeopts
  Sets the options passed by doexe et al. to the install command.
libopts
  Sets the options passed by dolib et al. to the install command.

##### 11.3.3.10 Commands affecting install compression

DOCOMPRESS

In EAPIs listed in table 11.16 as supporting controllable compression, the package manager may optionally compress a subset of the files under the ED directory in offset-prefix aware EAPIs or the D directory in offset-prefix agnostic EAPIs. To control which directories may or may not be compressed, the package manager shall maintain two lists:

- An inclusion list, which initially contains /usr/share/doc, /usr/share/info and /usr/share/man.
- An exclusion list, which initially contains /usr/share/doc/${PF}/html.

The optional compression shall be carried out after src_install has completed, and before the execution of any subsequent phase function. For each item in the inclusion list, pretend it has the value of the ED variable in offset-prefix aware EAPIs or the D variable in offset-prefix agnostic EAPIs prepended, then:

- If it is a directory, act as if every file or directory immediately under this directory were in the inclusion list.
- If the item is a file, it may be compressed unless it has been excluded as described below.
- If the item does not exist, it is ignored.

Whether an item is to be excluded is determined as follows: For each item in the exclusion list, pretend it has the value of the ED variable in offset-prefix aware EAPIs or the D variable in offset-prefix agnostic EAPIs prepended, then:

- If it is a directory, act as if every file or directory immediately under this directory were in the exclusion list.
- If the item is a file, it shall not be compressed.
- If the item does not exist, it is ignored.

The package manager shall take appropriate steps to ensure that its compression mechanisms behave sensibly even if an item is listed in the inclusion list multiple times, if an item is a symlink, or if a file is already compressed.

The following commands may be used in src_install to alter these lists. It is an error to call any of these functions from any other phase.

docompress
  If the first argument is -x, add each of its subsequent arguments to the exclusion list. Otherwise, add each argument to the inclusion list. Only available in EAPIs listed in table 11.16 as supporting docompress.

Table 11.16: EAPIs supporting controllable compression

EAPI | Supports controllable compression? | Supports docompress?
0 | No | No
1 | No | No
2 | No | No
3 | No | No
4 | Yes | Yes
5 | Yes | Yes

##### 11.3.3.11 Use List Functions

These functions provide behaviour based upon set or unset use flags. Ebuilds must not run any of these commands once the current phase function has returned. Ebuilds must not run any of these functions in global scope.

If any of these functions is called with a flag value that is not included in IUSE_EFFECTIVE, either behaviour is undefined or it is an error as decided by table 11.17.

use
  Returns shell true (0) if the first argument (a USE flag name) is enabled, false otherwise. If the flag name is prefixed with !, returns true if the flag is disabled, and false if it is enabled. It is guaranteed that this command is quiet.
usev
  The same as use, but also prints the flag name if the condition is met.
useq
  Deprecated synonym for use.
use_with

  USE-WITH Has one-, two-, and three-argument forms. The first argument is a USE flag name, the second a configure option name (${opt}), defaulting to the same as the first argument if not provided, and the third is a string value (${value}). For EAPIs listed in table 11.18 as not supporting it, an empty third argument is treated as if it weren’t provided. If the USE flag is set, outputs --with-${opt}=${value} if the third argument was provided, and --with-${opt} otherwise. If the flag is not set, then it outputs --without-${opt}.

use_enable
  Works the same as use_with(), but outputs --enable- or --disable- instead of --with- or --without-.
usex

  USEX Accepts at least one and at most five arguments. The first argument is a USE flag name, any subsequent arguments (${arg2} to ${arg5}) are string values. If not provided, ${arg2} and ${arg3} default to yes and no, respectively; ${arg4} and ${arg5} default to the empty string. If the USE flag is set, outputs ${arg2}${arg4}. Otherwise, outputs ${arg3}${arg5}. The condition is inverted if the flag name is prefixed with !. Only available in EAPIs listed in table 11.19 as supporting usex.

Table 11.17: EAPI Behaviour for Use Queries not in IUSE_EFFECTIVE

EAPI | Behaviour
0 | Undefined
1 | Undefined
2 | Undefined
3 | Undefined
4 | Error
5 | Error

Table 11.18: EAPIs supporting empty third argument in use_with and use_enable

EAPI | Supports empty third argument?
0 | No
1 | No
2 | No
3 | No
4 | Yes
5 | Yes

Table 11.19: EAPIs supporting usex

EAPI | Supports usex?
0 | No
1 | No
2 | No
3 | No
4 | No
5 | Yes

##### 11.3.3.12 Text List Functions

These functions check whitespace-separated lists for a particular value.

has
  Returns shell true (0) if the first argument (a word) is found in the list of subsequent arguments, false otherwise. Guaranteed quiet.
hasv
  The same as has, but also prints the first argument if found.
hasq
  Deprecated synonym for has.

##### 11.3.3.13 Misc Commands

The following commands are always available in the ebuild environment, but don’t really fit in any of the above categories. Ebuilds must not run any of these commands once the current phase function has returned.

dosed
  Takes any number of arguments, which can be files or sed expressions. For each argument, if it names, relative to ED (offset-prefix aware EAPIs) or D (offset-prefix agnostic EAPIs) a file which exists, then sed is run with the current expression on that file. Otherwise, the current expression is set to the text of the argument. The initial value of the expression is s:${ED}::g in offset-prefix aware EAPIs and s:${D}::g in offset-prefix agnostic EAPIs. In EAPIs listed in table 11.8, this command is banned as per section 11.3.3.2.
unpack
  Unpacks one or more source archives, in order, into the current directory. After unpacking, must ensure that all filesystem objects inside the current working directory (but not the current working directory itself) have permissions a+r,u+w,go-w and that all directories under the current working directory additionally have permissions a+x.

  All arguments to unpack must be either a filename without path, in which case unpack looks in DISTDIR for the file, or start with the string ./, in which case unpack uses the argument as a path relative to the working directory.

  Any unrecognised file format shall be skipped silently. If unpacking a supported file format fails, unpack shall abort the build process.

  UNPACK-EXTENSIONS

  Must be able to unpack the following file formats, if the relevant binaries are available:

  - tar files (*.tar). Ebuilds must ensure that GNU tar installed.
  - gzip-compressed tar files (*.tar.gz, *.tgz, *.tar.Z, *.tbz). Ebuilds must ensure that GNU gzip and GNU tar are installed.
  - bzip2-compressed tar files (*.tar.bz2, *.tbz2, *.tar.bz). Ebuilds must ensure that bzip2 and GNU tar are installed.
  - zip files (*.zip, *.ZIP, *.jar). Ebuilds must ensure that Info-ZIP Unzip is installed.
  - gzip files (*.gz, *.Z, *.z). Ebuilds must ensure that GNU gzip is installed.
  - bzip2 files (*.bz, *.bz2). Ebuilds must ensure that bzip2 is installed.
  - 7zip files (*.7z, *.7Z). Ebuilds must ensure that P7ZIP is installed.
  - rar files (*.rar, *.RAR). Ebuilds must ensure that RARLAB’s unrar is installed.
  - LHA archives (*.LHA, *.LHa, *.lha, *.lhz). Ebuilds must ensure that the lha program is installed.
  - ar archives (*.a). Ebuilds must ensure that GNU binutils is installed.
  - deb packages (*.deb). Ebuilds must ensure that the deb2targz program is installed on those platforms where the GNU binutils ar program is not available and the installed ar program is incompatible with GNU archives. Otherwise, ebuilds must ensure that GNU binutils is installed.
  - lzma-compressed files (*.lzma). Ebuilds must ensure that LZMA Utils is installed.
  - lzma-compressed tar files (*.tar.lzma). Ebuilds must ensure that LZMA Utils and GNU tar are installed.
  - xz-compressed files (*.xz). Ebuilds must ensure that XZ Utils is installed. Only for EAPIs listed in table 11.20 as supporting xz.
  - xz-compressed tar files (*.tar.xz). Ebuilds must ensure that XZ Utils and GNU tar are installed. Only for EAPIs listed in table 11.20 as supporting xz.

  It is up to the ebuild to ensure that the relevant external utilities are available, whether by being in the system set or via dependencies.

  Table 11.20: unpack extensions for EAPIs

  EAPI | .xz and .tar.xz?
  0 | No
  1 | No
  2 | No
  3 | Yes
  4 | Yes
  5 | Yes

inherit
  See section 10.1.
default

  DEFAULT-FUNC Calls the default_ function for the current phase (see section 9.1.17). Must not be called if the default_ function does not exist for the current phase in the current EAPI. Only available in EAPIs listed in table 11.21.

Table 11.21: EAPIs supporting the default function

EAPI | Supports default function?
0 | No
1 | No
2 | Yes
3 | Yes
4 | Yes
5 | Yes

##### 11.3.3.14 Debug Commands

The following commands are available for debugging. Normally all of these commands should be no ops; a package manager may provide a special debug mode where these commands instead do something. Ebuilds must not run any of these commands once the current phase function has returned.

debug-print
  If in a special debug mode, the arguments should be outputted or recorded using some kind of debug logging.
debug-print-function
  Calls debug-print with $1: entering function as the first argument and the remaining arguments as additional arguments.
debug-print-section
  Calls debug-print with now in section $*.

##### 11.3.3.15 Reserved Commands and Variables

Except where documented otherwise, all functions and variables that contain any of the following strings (ignoring case) are reserved for package manager use and may not be used or relied upon by ebuilds:

- __ (two underscores) at beginning of string
- abort
- dyn
- ebuild
- hook
- paludis
- portage
- prep

### 11.4 The state of the system between functions

For the sake of this section:

- Variancy is any package manager action that modifies either ROOT or / in any way that isn’t merely a simple addition of something that doesn’t alter other packages. This includes any non-default call to any pkg phase function except pkg_setup, a merge of any package or an unmerge of any package.
- As an exception, changes to DISTDIR do not count as variancy.
- The pkg_setup function may be assumed not to introduce variancy. Thus, ebuilds must not perform variant actions in this phase.

The following exclusivity and invariancy requirements are mandated:

- No variancy shall be introduced at any point between a package’s pkg_setup being started up to the point that that package is merged, except for any variancy introduced by that package.
- There must be no variancy between a package’s pkg_setup and a package’s pkg_ postinst, except for any variancy introduced by that package.
- Any non-default pkg phase function must be run exclusively.
- Each phase function must be called at most once during the build process for any given package.

## Chapter 12
Merging and Unmerging

Note: In this chapter, file and regular file have their Unix meanings.

### 12.1 Overview

The merge process merges the contents of the D directory onto the filesystem under ROOT. This is not a straight copy; there are various subtleties which must be addressed.

The unmerge process removes an installed package’s files. It is not covered in detail in this specification.

### 12.2 Directories

Directories are merged recursively onto the filesystem. The method used to perform the merge is not specified, so long as the end result is correct. In particular, merging a directory may alter or remove the source directory under D.

Ebuilds must not attempt to merge a directory on top of any existing file that is not either a directory or a symlink to a directory.

#### 12.2.1 Permissions

The owner, group and mode (including set*id and sticky bits) of the directory must be preserved, except as follows:

- Any directory owned by the user used to perform the build must become owned by the root user.
- Any directory whose group is the primary group of the user used to perform the build must have its group be that of the root user.

On SELinux systems, the SELinux context must also be preserved. Other directory attributes, including modification time, may be discarded.

#### 12.2.2 Empty Directories

Behaviour upon encountering an empty directory is undefined. Ebuilds must not attempt to install an empty directory.

### 12.3 Regular Files

Regular files are merged onto the filesystem (but see the notes on configuration file protection, below). The method used to perform the merge is not specified, so long as the end result is correct. In particular, merging a regular file may alter or remove the source file under D.

Ebuilds must not attempt to merge a regular file on top of any existing file that is not either a regular file or a symlink to a regular file.

#### 12.3.1 Permissions

The owner, group and mode (including set*id and sticky bits) of the file must be preserved, except as follows:

- Any file owned by the user used to perform the build must become owned by the root user.
- Any file whose group is the primary group of the user used to perform the build must have its group be that of the root user.
- The package manager may reduce read and write permissions on executable files that have a set*id bit set.

On SELinux systems, the SELinux context must also be preserved. Other file attributes may be discarded.

#### 12.3.2 File modification times

MTIME-PRESERVE

In EAPIs listed in table 12.1, the package manager must preserve modification times of regular files. This includes files being compressed before merging. Exceptions to this are files newly created by the package manager and binary object files being stripped of symbols.

When preserving, the seconds part of every regular file’s mtime must be preserved exactly. The sub-second part must either be set to zero, or set to the greatest value supported by the operating system and filesystem that is not greater than the sub-second part of the original time.

For any given destination filesystem, the package manager must ensure that for any two preserved files a, b in that filesystem the relation mtime(a) ≤ mtime(b) still holds, if it held under the original image directory.

In other EAPIs, the behaviour with respect to file modification times is undefined.

Table 12.1: Preservation of file modification times (mtimes)

EAPI | mtimes preserved?
0 | Undefined
1 | Undefined
2 | Undefined
3 | Yes
4 | Yes
5 | Yes

#### 12.3.3 Configuration File Protection

The package manager must provide a means to prevent user configuration files from being overwritten by any package updates. The profile variables CONFIG_PROTECT and CONFIG_PROTECT_MASK (section 5.3) control the paths for which this must be enforced.

In order to ensure interoperability with configuration update tools, the following scheme must be used by all package managers when merging any regular file:

1.
  If the directory containing the file to be merged is not listed in CONFIG_PROTECT, and is not a subdirectory of any such directory, and if the file is not listed in CONFIG_PROTECT, the file is merged normally.
2.
  If the directory containing the file to be merged is listed in CONFIG_PROTECT_MASK, or is a subdirectory of such a directory, or if the file is listed in CONFIG_PROTECT_MASK, the file is merged normally.
3.
  If no existing file with the intended filename exists, or the existing file has identical content to the one being merged, the file is installed normally.
4.
  Otherwise, prepend the filename with ._cfg0000_. If no file with the new name exists, then the file is merged with this name.
5.
  Otherwise, increment the number portion (to form ._cfg0001_<name>) and repeat step 4. Continue this process until a usable filename is found.
6.
  If 9999 is reached in this way, behaviour is undefined.

### 12.4 Symlinks

Symlinks are merged as symlinks onto the filesystem. The link destination for a merged link shall be the same as the link destination for the link under D, except as noted below. The method used to perform the merge is not specified, so long as the end result is correct; in particular, merging a symlink may alter or remove the symlink under D.

Ebuilds must not attempt to merge a symlink on top of a directory.

#### 12.4.1 Rewriting

Any absolute symlink whose link starts with D must be rewritten with the leading D removed. The package manager should issue a notice when doing this.

### 12.5 Hard links

A hard link may be merged either as a single file with links or as multiple independent files.

### 12.6 Other Files

Ebuilds must not attempt to install any other type of file (FIFOs, device nodes etc).

## Chapter 13
Metadata Cache

### 13.1 Directory Contents

The profiles/metadata/cache directory, if it exists, contains directories whose names are the same as categories in the repository. Each subdirectory may optionally contain one file per package version in that category, named <package>-<version>, in the format described below.

The metadata cache may be incomplete or non-existent, and may contain additional bogus entries.

### 13.2 Cache File Format

Each cache file contains the textual values of various metadata keys, one per line, in the following order. Other lines may be present following these; their meanings are not defined here.

1.
  Build-time dependencies (DEPEND)
2.
  Run-time dependencies (RDEPEND)
3.
  Slot (SLOT)
4.
  Source tarball URIs (SRC_URI)
5.
  RESTRICT
6.
  Package homepage (HOMEPAGE)
7.
  Package license (LICENSE)
8.
  Package description (DESCRIPTION)
9.
  Package keywords (KEYWORDS)
10.
  Inherited eclasses (INHERITED)
11.
  Use flags that this package respects (IUSE)
12.
  Use flags that this package requires (REQUIRED_USE). Blank in some EAPIs; see table 7.2.
13.
  Post dependencies (PDEPEND)
14.
  Unused; previously used for old-style virtual PROVIDE.
15.
  The ebuild API version to which this package conforms (EAPI)
16.
  Properties (PROPERTIES). In some EAPIs, may optionally be blank, regardless of ebuild metadata; see table 7.2.
17.
  Defined phases (DEFINED_PHASES). In some EAPIs, may optionally be blank, regardless of ebuild metadata; see table 7.4.
18.
  Blank lines to pad the file to 22 lines long

Future EAPIs may define new variables, remove existing variables, change the line number or format used for a particular variable, add or reduce the total length of the file and so on. Any future EAPI that uses this cache format will continue to place the EAPI value on line 15 if such a concept makes sense for that EAPI, and will place a value that is clearly not a supported EAPI on line 15 if it does not.

## Chapter 14
Glossary

This section contains explanations of some of the terms used in this document whose meaning may not be immediately obvious.

qualified package name
  A package name along with its associated category. For example, app-editors/vim is a qualified package name.
new-style virtual
  A new-style virtual is a normal package in the virtual category which installs no files and uses its dependency requirements to pull in a ‘provider’. Historically, old-style virtuals required special handling from the package manager; new-style virtuals do not.
stand-alone repository
  An (ebuild) repository which is intended to function on its own as the only, or primary, repository on a system. Contrast with slave repository below.
slave repository, non-stand-alone repository
  An (ebuild) repository which is not complete enough to function on its own, but needs one or more master repositories to satisfy dependencies and provide repository-level support files. Known in Portage as an overlay.
master repository
  See above.

## Appendix A
metadata.xml

The metadata.xml file is used to contain extra package- or category-level information beyond what is stored in ebuild metadata. Its exact format is strictly beyond the scope of this document, and is described in the DTD file located at http://www.gentoo.org/dtd/metadata.dtd.

## Appendix B
Unspecified Items

The following items are not specified by this document, and must not be relied upon by ebuilds. This is, of course, an incomplete list—it covers only the things that the authors know have been abused in the past.

- The FEATURES variable. This is Portage specific.
- Similarly, any EMERGE_ variable and any PORTAGE_ variable not explicitly listed.
- Any Portage configuration file.
- The VDB (/var/db/pkg). Ebuilds must not access this or rely upon it existing or being in any particular format.
- The portageq command. The has_version and best_version commands are available as functions.
- The emerge command.
- Binary packages.
- The PORTDIR_OVERLAY variable, and overlay behaviour in general.

## Appendix C
Historical Curiosities

The items described in this chapter are included for information only. They were deprecated or abandoned long before EAPI was introduced. Ebuilds must not use these features, and package managers should not be changed to support them.

### C.1 If-else use blocks

Historically, Portage supported if-else use conditionals, as shown by listing C.1. The block before the colon would be taken if the condition was met, and the block after the colon would be taken if the condition was not met.

This feature was deprecated and removed from the tree long before the introduction of EAPI.

Listing C.1: If-else use blocks
DEPEND="
flag? (
taken/if-true
) : (
taken/if-false
)
"

### C.2 cvs Versions

Portage has very crude support for CVS packages. The package foo could contain a file named foo-cvs.1.2.3.ebuild. This version would order higher than any non-CVS version (including foo-2.ebuild). This feature has not seen real world use and breaks versioned dependencies, so it must not be used.

### C.3 use.defaults

The use.defaults file in the profile directory was used to implement ‘autouse’—switching USE flags on or off depending upon which packages are installed. It was deprecated long ago and finally removed in 2009.

### C.4 Old-style Virtuals

Historically, virtuals were special packages rather than regular ebuilds. An ebuild could specify in the PROVIDE metadata that it supplied certain virtuals, and the package manager had to bear this in mind when handling dependencies.

Old-style virtuals were supported by EAPIs 0, 1, 2, 3 and 4, and were phased out via GLEP 37 [2].

## Appendix D
Feature Availability by EAPI

Note: This chapter is informative and for convenience only. Refer to the main text for specifics.

Table D.1: Features in EAPIs
Feature | Reference | EAPIs
|  | 0 | 1 | 2 | 3 | 4 | 5
Stable use masking/forcing | stablemask p59 | No | No | No | No | No | Yes
IUSE defaults | iuse-defaults p77 | No | Yes | Yes | Yes | Yes | Yes
REQUIRED_USE | required-use p77 | No | No | No | No | Yes | Yes
PROPERTIES | properties p77 | Optionally | Optionally | Optionally | Optionally | Yes | Yes
RDEPEND=DEPEND | rdepend-depend p84 | Yes | Yes | Yes | Yes | No | No
DEFINED_PHASES | defined-phases p88 | Optionally | Optionally | Optionally | Optionally | Yes | Yes
?? ( ) groups | at-most-one-of p98 | No | No | No | No | No | Yes
SRC_URI arrows | src-uri-arrows p116 | No | No | Yes | Yes | Yes | Yes
Slot dependencies | slot-deps p114 | No | Named | Named | Named | Named | Named and Operator
Sub-slots | sub-slot p114 | No | No | No | No | No | Yes
Use dependencies | use-deps p105 | No | No | 2-style | 2-style | 4-style | 4-style
! blockers | bang-strength p111 | Unspecified | Unspecified | Weak | Weak | Weak | Weak
!! blockers | bang-strength p111 | Forbidden | Forbidden | Strong | Strong | Strong | Strong
S to WORKDIR fallback | s-workdir-fallback p119 | Always | Always | Always | Always | Conditional | Conditional
pkg_pretend | pkg-pretend p122 | No | No | No | No | Yes | Yes
src_prepare | src-prepare p126 | No | No | Yes | Yes | Yes | Yes
src_configure | src-configure p129 | No | No | Yes | Yes | Yes | Yes
src_compile style | src-compile p133 | 0 | 1 | 2 | 2 | 2 | 2
Parallel tests | parallel-tests p139 | No | No | No | No | No | Yes
src_install style | src-install p142 | no-op | no-op | no-op | no-op | 4 | 4
pkg_info | pkg-info p147 | Installed | Installed | Installed | Installed | Both | Both
default_ phase functions | default-phase-funcs p150 | None | None | pkg_ nofetch, src_unpack, src_ prepare, src_ configure, src_ compile, src_test | pkg_ nofetch, src_unpack, src_ prepare, src_ configure, src_ compile, src_test | pkg_ nofetch, src_unpack, src_ prepare, src_ configure, src_ compile, src_ install, src_test | pkg_ nofetch, src_unpack, src_ prepare, src_ configure, src_ compile, src_ install, src_test
AA | aa p167 | Yes | Yes | Yes | Yes | No | No
KV | kv p171 | Yes | Yes | Yes | Yes | No | No
EBUILD_PHASE_FUNC | ebuild-phase-func p170 | No | No | No | No | No | Yes
MERGE_TYPE | merge-type p171 | No | No | No | No | Yes | Yes
Profile IUSE injection | profile-iuse-inject p182 | No | No | No | No | No | Yes
REPLACING_VERSIONS | replace-version-vars p183 | No | No | No | No | Yes | Yes
REPLACED_BY_VERSION | replace-version-vars p183 | No | No | No | No | Yes | Yes
EPREFIX, ED, EROOT | offset-prefix-vars p186 | No | No | No | Yes | Yes | Yes
find is GNU? | gnu-find p189 | Undefined | Undefined | Undefined | Undefined | Undefined | Yes
Most utilities die | die-on-failure p192 | No | No | No | No | Yes | Yes
nonfatal | nonfatal p192 | No | No | No | No | Yes | Yes
dohard | banned-commands p195 | Yes | Yes | Yes | Yes | Banned | Banned
dosed | banned-commands p195 | Yes | Yes | Yes | Yes | Banned | Banned
Option --host-root | host-root-option p198 | No | No | No | No | No | Yes
econf arguments | econf-options p199 |  |  |  |  | disable dependency tracking | disable dependency tracking, disable silent rules
dodoc -r | dodoc p202 | No | No | No | No | Yes | Yes
doheader | doheader p203 | No | No | No | No | No | Yes
doins handles symlinks | doins p204 | No | No | No | No | Yes | Yes
doman languages | doman-langs p205 | No | No | Yes | Yes | Yes | Yes
doman -i18n precedence | doman-langs p205 | N/A | N/A | No | No | Yes | Yes
new* support stdin | newfoo-stdin p205 | No | No | No | No | No | Yes
Controllable compression | docompress p224 | No | No | No | No | Yes | Yes
docompress | docompress p224 | No | No | No | No | Yes | Yes
use_with empty third arg | use-with p228 | No | No | No | No | Yes | Yes
usex | usex p228 | No | No | No | No | No | Yes
unpack support for xz? | unpack-extensions p237 | No | No | No | Yes | Yes | Yes
default function | default-func p239 | No | No | Yes | Yes | Yes | Yes
File mtimes preserved | mtime-preserve p247 | Undefined | Undefined | Undefined | Yes | Yes | Yes

## Appendix E
Differences Between EAPIs

Note: This chapter is informative and for convenience only. Refer to the main text for specifics.

### EAPI 0

EAPI 0 is the base EAPI.

### EAPI 1

EAPI 1 is EAPI 0 with the following changes:

- IUSE defaults, IUSE-DEFAULTS on page 77.
- Slot dependencies, SLOT-DEPS on page 114.
- Different src_compile implementation, SRC-COMPILE-1 on page 134.

### EAPI 2

EAPI 2 is EAPI 1 with the following changes:

- Use dependencies, USE-DEPS on page 105.
- ! and !! blockers, BANG-STRENGTH on page 111.
- SRC_URI arrows, SRC-URI-ARROWS on page 116.
- src_prepare, SRC-PREPARE on page 126.
- src_configure, SRC-CONFIGURE on page 129.
- Different src_compile implementation, SRC-COMPILE-2 on page 135.
- default_ phase functions for phases pkg_nofetch, src_unpack, src_prepare, src_ configure, src_compile and src_test; DEFAULT-PHASE-FUNCS on page 150.
- doman language detection by filename, DOMAN-LANGS on page 205.
- default function, DEFAULT-FUNC on page 239.

### EAPI 3

EAPI 3 is EAPI 2 with the following changes:

- Offset-prefix support by definition of EPREFIX, ED and EROOT, OFFSET-PREFIX-VARS on page 186.
- unpack supports .xz and .tar.xz, UNPACK-EXTENSIONS on page 237.
- File modification times are preserved, MTIME-PRESERVE on page 247.

### EAPI 4

EAPI 4 is EAPI 3 with the following changes:

- PROPERTIES support is mandatory, PROPERTIES on page 77.
- REQUIRED_USE, REQUIRED-USE on page 77.
- RDEPEND=DEPEND no longer done, RDEPEND-DEPEND on page 84.
- DEFINED_PHASES support is mandatory, DEFINED-PHASES on page 88.
- Use dependency defaults, USE-DEP-DEFAULTS on page 115.
- S to WORKDIR fallback restricted, S-WORKDIR-FALLBACK on page 119.
- pkg_pretend, PKG-PRETEND on page 122.
- Default src_install no longer a no-op, SRC-INSTALL-4 on page 142.
- pkg_info can run on non-installed packages, PKG-INFO on page 147.
- AA is gone, AA on page 167.
- KV is gone, KV on page 171.
- MERGE_TYPE, MERGE-TYPE on page 171.
- REPLACING_VERSIONS and REPLACED_BY_VERSION, REPLACE-VERSION-VARS on page 183.
- Utilities now die on failure, DIE-ON-FAILURE on page 192, unless called under nonfatal, NONFATAL on page 192
- dohard, dosed banned, BANNED-COMMANDS on page 195.
- econf adds --disable-dependency-tracking, ECONF-OPTIONS on page 199.
- dodoc -r support, DODOC on page 202.
- doins supports symlinks, DOINS on page 204.
- doman -i18n option takes precedence, DOMAN-LANGS on page 205.
- Controllable compression and docompress, DOCOMPRESS on page 224.
- use_with and use_enable support empty third argument, USE-WITH on page 228.

### EAPI 5

EAPI 5 is EAPI 4 with the following changes:

- Stable use masking and forcing, STABLEMASK on page 59.
- REQUIRED_USE now supports ?? groups, AT-MOST-ONE-OF on page 98.
- Slot operator dependencies, SLOT-OPERATOR-DEPS on page 114.
- SLOT now supports an optional sub-slot part, SUB-SLOT on page 114.
- src_test supports parallel tests, PARALLEL-TESTS on page 139.
- EBUILD_PHASE_FUNC, EBUILD-PHASE-FUNC on page 170.
- USE is calculated differently, PROFILE-IUSE-INJECT on page 182.
- find is guaranteed to be GNU, GNU-FIND on page 189.
- best_version and has_version support the --host-root option, HOST-ROOT-OPTION on page 198.
- econf adds --disable-silent-rules, ECONF-OPTIONS on page 199.
- doheader and newheader support, DOHEADER on page 203.
- new* can read from standard input, NEWFOO-STDIN on page 205.
- usex support, USEX on page 228.

## Bibliography

[1] Marius Mauch. GLEP 44: Manifest2 format. http://glep.gentoo.org/glep-0044.html, December 2005.

[2] Jason Stubbs. GLEP 37: Virtuals deprecation. http://glep.gentoo.org/glep-0037.html, April 2005.

## Appendix F
Desk Reference

EAPI Cheat Sheet