Chapter 9. pkg-*

There are some tricks we have not mentioned yet about the pkg-* files that come in handy sometimes.

9.1. pkg-message

To display a message when the package is installed, place the message in pkg-message. This capability is often useful to display additional installation steps to be taken after a pkg install or pkg upgrade.

  • pkg-message must contain only information that is vital to setup and operation on FreeBSD, and that is unique to the port in question.

  • Setup information should only be shown on initial install. Upgrade instructions should be shown only when upgrading from the relevant version.

  • Do not surround the messages with either whitespace or lines of symbols (like ----------, , or ==========). Leave the formatting to pkg(8).

  • Committers have blanket approval to constrain existing messages to install or upgrade ranges using the UCL format specifications.

pkg-message supports two formats:

raw

A regular plain text file. Its message is only displayed on install.

UCL

If the file starts with “[” then it is considered to be a UCL file. The UCL format is described on libucl’s GitHub page.

Do not add an entry for pkg-message in pkg-plist.

9.1.1. UCL in pkg-message

The format is the following. It should be an array of objects. The objects themselves can have these keywords:

message

The actual message to be displayed. This keyword is mandatory.

type

When the message should be displayed.

maximum_version

Only if type is upgrade. Display if upgrading from a version strictly lower than the version specified.

minimum_version

Only if type is upgrade. Display if upgrading from a version strictly greater than the version specified.

The maximum_version and minimum_version keywords can be combined.

The type keyword can have three values:

install

The message should only be displayed when the package is installed.

remove

The message should only be displayed when the package is removed.

upgrade

the message should only be displayed during an upgrade of the package..

To preserve the compatibility with non UCL pkg-message files, the first line of a UCL pkg-message MUST be a single “[”, and the last line MUST be a single “]”.

Example 1. UCL Short Strings

The message is delimited by double quotes ", this is used for simple single line strings:

[
{ type: install
  message: "Simple message"
}
]
Example 2. UCL Multiline Strings

Multiline strings use the standard here document notation. The multiline delimiter must start just after << symbols without any whitespace and it must consist of capital letters only. To finish a multiline string, add the delimiter string on a line of its own without any whitespace. The message from UCL Short Strings can be written as:

[
{ type: install
  message: <<EOM
Simple message
EOM
}
]
Example 3. Display a Message on Install/Deinstall

When a message only needs to be displayed on installation or uninstallation, set the type:

[
{
  type: remove
  message: "package being removed."
}
{ type: install, message: "package being installed."}
]
Example 4. Display a Message on Upgrade

When a port is upgraded, the message displayed can be even more tailored to the port’s needs.

[
{
  type: upgrade
  message: "Package is being upgraded."
}
{
  type: upgrade
  maximum_version: "1.0"
  message: "Upgrading from before 1.0 need to do this."
}
{
  type: upgrade
  minimum_version: "1.0"
  message: "Upgrading from after 1.0 should do that."
}
{
  type: upgrade
  maximum_version: "3.0"
  minimum_version: "1.0"
  message: "Upgrading from > 1.0 and < 3.0 remove that file."
}
]

When displaying a message on upgrade, it is important to limit when it is being shown to the user. Most of the time it is by using maximum_version to limit its usage to upgrades from before a certain version when something specific needs to be done.

9.2. pkg-install, pkg-pre-install, and pkg-post-install

If the port needs to execute commands when the binary package is installed with pkg add or pkg install, use pkg-install. It is run twice by pkg, the first time as ${SH} pkg-install ${PKGNAME} PRE-INSTALL before the package is installed, and the second time as ${SH} pkg-install ${PKGNAME} POST-INSTALL after it has been installed. $2 can be tested to determine which mode the script is being run in. The PKG_PREFIX environment variable is set to the package installation directory.

If using pkg-pre-install or pkg-post-install instead, the script is run only once (before or after installing the package), with the single argument ${PKGNAME}. Using pkg-pre-install.lua or pkg-post-install.lua will run a lua script instead of a shell script. Lua scripts run by pkg provide some extensions and a few restrictions, both explained in pkg-lua-script(5).

Using pkg-pre-install (or pkg-pre-install.lua) and pkg-post-install (or pkg-post-install.lua) is preferred to using pkg-install.

These scripts are automatically added to the packing list.

These scripts are here to simplify package configuration after installation. They must not be abused to start services, stop services, or run any other commands that will modify the currently running system.

9.3. pkg-deinstall, pkg-pre-deinstall, and pkg-post-deinstall

These scripts execute when a package is removed.

The pkg-deinstall script is run twice by pkg delete. The first time as ${SH} pkg-deinstall ${PKGNAME} DEINSTALL before the port is de-installed and the second time as ${SH} pkg-deinstall ${PKGNAME} POST-DEINSTALL after the port has been de-installed. $2 can be tested to determine which mode the script is being run in. The PKG_PREFIX environment variable is set to the package installation directory.

If using pkg-pre-deinstall or pkg-post-deinstall instead, the script is run only once (before or after deinstalling the package), with the single argument ${PKGNAME}. Using pkg-pre-deinstall.lua or pkg-post-deinstall.lua will run a lua script instead of a shell script. Lua scripts run by pkg provide some extensions and a few restrictions, both explained in pkg-lua-script(5).

Using pkg-pre-deinstall (or pkg-pre-deinstall.lua) and pkg-post-deinstall (or pkg-post-deinstall.lua) is preferred to using pkg-deinstall.

These scripts are automatically added to the packing list.

These scripts are here to simplify cleanup after package deinstallation. They must not be abused to start services, stop services, or run any other commands that will modify the currently running system.

9.4. Changing the Names of pkg-*

All the names of pkg-* are defined using variables that can be changed in the Makefile if needed. This is especially useful when sharing the same pkg-* files among several ports or when it is necessary to write to one of these files. See writing to places other than WRKDIR for why it is a bad idea to write directly into the directory containing the pkg-* files.

Here is a list of variable names and their default values. (PKGDIR defaults to ${MASTERDIR}.)

VariableDefault value

DESCR

${PKGDIR}/pkg-descr

PLIST

${PKGDIR}/pkg-plist

PKGINSTALL

${PKGDIR}/pkg-install

PKGPREINSTALL

${PKGDIR}/pkg-pre-install

PKGPOSTINSTALL

${PKGDIR}/pkg-post-install

PKGDEINSTALL

${PKGDIR}/pkg-deinstall

PKGPREDEINSTALL

${PKGDIR}/pkg-pre-deinstall

PKGPOSTDEINSTALL

${PKGDIR}/pkg-post-deinstall

PKGMESSAGE

${PKGDIR}/pkg-message

9.5. Making Use of SUB_FILES and SUB_LIST

SUB_FILES and SUB_LIST are useful for dynamic values in port files, such as the installation PREFIX in pkg-message.

SUB_FILES specifies a list of files to be automatically modified. Each file in the SUB_FILES list must have a corresponding file.in present in FILESDIR. A modified version will be created as ${WRKDIR}/file. Files defined as a value of USE_RC_SUBR are automatically added to SUB_FILES. For the files pkg-message, pkg-install, and pkg-deinstall, the corresponding Makefile variable is automatically set to point to the processed version.

SUB_LIST is a list of VAR=VALUE pairs. For each pair, %%VAR%% will be replaced with VALUE in each file listed in SUB_FILES. Several common pairs are automatically defined: PREFIX, LOCALBASE, DATADIR, DOCSDIR, EXAMPLESDIR, WWWDIR, and ETCDIR. Any line beginning with @comment followed by a space, will be deleted from resulting files after a variable substitution.

This example replaces %%ARCH%% with the system architecture in a pkg-message:

SUB_FILES=	pkg-message
SUB_LIST=	ARCH=${ARCH}

Note that for this example, pkg-message.in must exist in FILESDIR.

Example of a good pkg-message.in:

Now it is time to configure this package.
Copy %%PREFIX%%/shared/examples/putsy/%%ARCH%%.conf into your home directory
as .putsy.conf and edit it.

Last modified on: September 27, 2022 by Pau Amma