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pkgfile.5: new draft before the CRUX 3.7 release

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.\"
.\" Pkgfile manual page.
.\" (C) 2018 by Fun, updated 2021--2022 by John McQuah <jmcquah at disroot dot org>
.\"
.TH Pkgfile 5
.SH NAME
Pkgfile \- sourced by \fBpkgmk\fP(8) when building a package in the ports tree
.SH DESCRIPTION
a \fBbash\fP(1) script that tells \fBpkgmk\fP(8) where the source code for a port may be downloaded,
and what to do once that source code is unpacked.
.SH FILE FORMAT
\fBPkgfile\fP starts with a header of commented lines, which are read by \fBprt-get\fP(8)
to resolve dependencies, or by \fBportspage\fP(1) to generate an HTML index of the ports collection.
After the header \fBpkgmk\fP will expect to find definitions of several mandatory variables, including
\fIname\fP, \fIversion\fP, \fIrelease\fP, the bash array \fIsource\fP, and
the bash function \fIbuild()\fP.
.SS Example:
.EX
# Description: A library for demonstrating how to create delicious ports.
# URL: http://www.gnu.org/software/somelib/index.html
# Maintainer: Joe Maintainer, joe at myfantasticisp dot net
# Depends on: someotherlib coolness
name=somelib
version=1.2.3
release=1
source=(ftp://ftp.gnu.org/gnu/$name/archive/$version/$version.tar.gz Makefile.in.patch)
renames=($name-$version.tar.gz SKIP)
build() {
cd $name-$version
patch -p1 < ../Makefile.in.patch
./configure --prefix=/usr
make
make DESTDIR=$PKG install
rm -rf $PKG/usr/info
}
.EE
.SS General guidelines
The name of a package should always be lowercase (e.g. \fBname=eterm\fP and
not \fBname=Eterm\fP). In case the package is added to the CRUX ports system
the exact same name should be used for the name of the directory in the
ports structure, i.e. \fI/usr/ports/???/eterm\fP.
.LP
Do not combine several separately distributed programs/libraries into
one package. Make several packages instead.
.LP
Use \fBprtverify\fP to check the port. This script uses bash and awk to identify
common errors, such as writing to a directory outside $PKG, or forgetting to remove
\(dqjunk files\(dq.
.LP
Ideally, nothing in the \fIbuild\fP function should assume internet
connectivity. All fetching from remote servers should be limited to the
\fBcurl(1)\fP or \fBwget(1)\fP processes that run when \fBpkgmk(8)\fP parses
the \fIsource\fP array. This separation between download and build is meant
to accommodate users with intermittent internet access, who might like to run
\fBpkgmk -do\fP for each outdated port, and then go offline to continue the
build. While the inability of \fBpkgmk(8)\fP to parse \fBgit\fP urls in the
source array was historically the greatest temptation to violate the separation
between download and build, certain language ecosystems and build toolchains
also make it more difficult to achieve this separation. In particular, you
should be wary when the upstream project talks about \fImeson subprojects\fP or
\fIcargo fetch\fP commands in its compilation instructions, for which the most
CRUX-like solution is to write separate ports for each needed dependency (and
put them in the \(dqDepends on:\(dq line).
.SS Variable names
.LP
Do not add new variables to the \fBPkgfile\fP. Only in very few cases
does this actually improve the readability or the quality of the
package. Further, the only variables that are guaranteed to work with
future versions of \fBpkgmk\fP are \fIname\fP, \fIversion\fP, \fIrelease\fP,
and \fIsource\fP. Other names could be in conflict with internal variables
in \fBpkgmk\fP.
.LP
Use the \fI$name\fP and \fI$version\fP variables to make the
package easier to update/maintain. For example,
.EX
source=(http://xyz.org/$name-$version.tar.gz)
.EE
is better than
.EX
source=(http://xyz.org/myprog-1.0.3.tar.gz)
.EE
since the URL will automatically update when you modify the \fI$version\fP variable.
.SS Support for renaming source files
Note that in the \fBsomelib\fP example above, Joe Maintainer chose to define the optional bash array
\fIrenames\fP (same length as \fIsource\fP), so that the ambiguously-named file retrieved by FTP
would not collide with another port's files, if downloaded into a common directory.
The keyword \(oqSKIP\(cq was given in the \fIrenames\fP array to indicate that renaming was not
necessary for the corresponding source file. SKIP should always be used for a file retrieved by
\(oqports -u\(cq, because the port maintainer has the freedom to choose an unambiguous name in the
\fisource\fP array itself.
.PP
Tools from prior versions of CRUX (before 3.7), ignorant of the \fIrenames\fP array, will
execute the \fIbuild\fP function using the original filenames given by the
remote sources. For backwards compatibility, write a \fIbuild\fP function that
does not rely on the specific names chosen for downloaded sources (it helps that
the directory created by unpacking a tarball will have the same name, regardless
of how the tarball itself is saved on disk).
.PP
Starting with CRUX 3.7 you can use the \fIrenames\fP array to prevent automatic
unpacking of archives whose original filenames would have matched the pattern
*.(tar|tar.gz|tar.bz2|tar.xz|zip|rpm|7z); in previous CRUX versions the clunky
workaround was to redefine the \fBpkgmk(8)\fP function \fIunpack_source()\fP and
delay that pattern match until specially-designated source files are given
special treatment. Keeping in mind that earlier versions of CRUX will not respect the
renaming feature (and will gladly proceed to unpack the tarball that you wanted
left intact), during the transition period to CRUX 3.7 it is safer to stick with
the method of redefining \fIunpack_source()\fP to shield specific archives from
being extracted. (This advice only applies to user-published port collections;
the CRUX development team will push their ports to the 3.7 branch and not have
to worry about inadvertent attempts to compile them on earlier branches.)
.SS Directories
In general packages should install files in these directories. Exceptions
are of course allowed if there is a good reason. But try to follow the
following directory structure as closely as possible.
.EX
Directory Description
--------- ------------
/usr/bin/ User command/application binaries
/usr/sbin/ System binaries (e.g. daemons)
/usr/lib/ Libraries
/usr/include/ Header files
/usr/lib/<prog>/ Plug-ins, addons, etc
/usr/share/man/ Man pages
/usr/share/<prog>/ Data files
/usr/etc/<prog>/ Configuration files
/etc/ Configuration files for system software (daemons, etc)
.EE
.LP
\fI/opt\fP directory is reserved for manually compiled/installed
applications. Packages should never place anything there.
.LP
\fI/usr/libexec/\fP is not used in CRUX, thus packages should never
install anything there. Use \fI/usr/lib/<prog>/\fP instead.
.SS Junk files
.LP
Packages should not contain "junk files". This includes:
.IP \[bu] 2
info pages and other online documentation, man pages excluded (e.g. \fIusr/doc/*\fP,
\fIREADME\fP, \fI*.info\fP, \fI*.html\fP, etc).
.IP \[bu]
Files related to NLS (national language support). If \fB--disable-nls\fP is not available as
an option to \fBconfigure\fP, then manually inserting \(oqrm -rf $PKG/usr/share/locale\(cq near the
end of the \fBbuild\fP function is an acceptable alternative.
.IP \[bu]
Useless or obsolete binaries (e.g. \fI/usr/games/banner\fP and \fI/sbin/mkfs.minix\fP).
.LP
Apart from these global rules, the definition of "junk" is often a matter of personal taste.
One user might regard as "junk" the same files that another user sees as indispensible. See
\fBOptional dependencies\fP below for a simple way to let your port handle such
individual preferences automatically.
.SS Header
Provide a header including the following fields:
.EX
Name Meaning
---- -------
Description A short description of the package; keep it factual
Maintainer Your full name and e-mail address, obfuscated if you want
Packager The original packager's full name and e-mail address
URL A webpage with more information on this software package
Depends on A list of dependencies, separated either by spaces or commas
.EE
Note that you should use the obfuscated email address (illustrated in the example above) if
you want to put your ports in any of the official CRUX repositories.
\fIDepends on\fP can be omitted if there are no dependencies.
.SS Dependencies
Dependencies are supported by CRUX tools like \fBprt-get\fP and \fBpkg-get\fP.
The following rules should be respected:
.IP "" 4
List all runtime dependencies except for gcc (libstdc++) and glibc.
.IP "" 4
\fBcore\fP contains essential packages for a CRUX system, and our scripts
and ports expect the programs provided by \fBcore\fP to be installed; this
means that:
.IP "" 8
build dependencies provided by \fBcore\fP are not listed in the dependency header
.IP "" 8
run-time dependencies from \fBcore\fP which aren't dynamically linked in are not to be listed, either
.TP
Examples:
.IP "" 4
\fBopt/sloccount\fP does \fInot\fP list \fBperl\fP, because the program is a perl script -- there's no binary that links to \fBlibperl\fP
.IP "" 4
\fBopt/libxml2\fP \fIdoes\fP list \fBzlib\fP, because \fBlibxml\fP is linked to \fBlibz.so\fP.
.LP
The reasoning for these guidelines is that you can use \fBrevdep\fP to find ports
that need to be updated if one of the dependent libraries has become
binary incompatible. To find out what libraries a binary is linked to,
use \fBldd\fP or \fBfinddeps\fP.
.LP
It \fIis\fP permissible to list build dependencies outside of \fBcore\fP, whose only purpose is to
generate the manpage of the port. But if the dependency chain is too convoluted, try to find
alternative ways of providing such static documentation.
.TP
Examples:
.IP "" 4
\fBgreetd\fP \fIdoes\fP list \fBscdoc\fP (only needed to generate the manpages), because the dependency chain
leading to this dependency is just \fBscdoc\fP itself.
.IP "" 4
\fBmpd\fP does \fInot\fP list \fBpython3-sphinx\fP (only needed to generate the manpages), because of the
long dependency chain leading to \fBpython3-sphinx\fP, and the possibility of delivering the manpages by
simpler means.
.SS Optional dependencies
A common practice among port maintainers is to put filesystem tests in the \fIbuild\fP function,
allowing the package configuration to vary depending on what other packages the system administrator
has installed. This practice can result in footprint mismatches. It is recommended that
maintainers build their ports in a container with the bare minimum of dependencies, or prune the
auto-generated footprint so that the spurious files are not reported as MISSING on another user's
system.
.PP
Filesystem tests are also useful at the end of a \fIbuild\fP function, for example when determining
which shell completions should be installed. Here is a template for tests of this kind:
.EX
prt-get isinst bash-completion || rm -rf $PKG/usr/share/bash-completion
prt-get isinst zsh || rm -rf $PKG/usr/share/zsh
prt-get isinst fish || rm -rf $PKG/usr/share/fish
.EE
.PP
If the maintainer built the package in a clean container, then another user with fish installed will
see the path /usr/share/fish listed as NEW in the footprint mismatch, and that user can proceed with
installation if PKGMK_IGNORE_NEW was enabled in \fBpkgmk.conf\fP(5). More dangerous is the reverse
situation: the maintainer built the package in a system with fish, and a user without fish sees
/usr/share/fish listed as MISSING in the footprint mismatch. Users should not be encouraged to disregard
MISSING, but enabling PKGMK_IGNORE_NEW is generally safe.
.SS rc start scripts
You can use the following template for ports that provide some
sort of daemon. The runnable script should be called \fI$name.rc\fP,
and your port should install it to \fI/etc/rc.d/$name\fP. The installation
can happen by calling the following in your \fIbuild\fP function:
.EX
install -D -m 755 $SRC/$name.rc $PKG/etc/rc.d/$name
.EE
.LP
See the existing scripts under /etc/rc.d for examples of using \fBstart-stop-daemon\fP(8)
to generate the necessary pid files, temp directories, and logs for your daemon.
.SH ENVIRONMENT
.LP
The \fIbuild\fP function should use the \fI$SRC\fP variable whenever it needs
to access the files listed in the source variable, and the \fI$PKG\fP
variable as the root destination of the output files.
.LP
Being a shell script executed in the context of \fBpkgmk\fP(8), the
entire \fBPkgfile\fP has access to the variables initialized
in \fBpkgmk.conf\fP(5) and the default values set by \fBpkgmk\fP(8). Also, as a
side effect of how it is used by \fBpkgmk\fP(8), the Pkgfile can also
change the behaviour of \fBpkgmk\fP(8) by rewriting some of its functions
and variables before \fIbuild()\fP is called. However, the \fIbuild\fP
function itself has only read access to these environment variables
and shell functions.
.SH ERRORS
.LP
Most of the command failures in \fIbuild()\fP will stop
the build process. There is no need to explicitly check the return
codes. If you need/want to handle a command failure you should use
constructs like:
.EX
\fBif ! command...; then ...\fP
\fBcommand || ...\fP
.EE
.SH SEE ALSO
pkgmk(8), pkgmk.conf(5),
.UR https://crux.nu/Main/PortGuidelines
.UE ,
.UR https://crux.nu/Main/PrePostInstallGuidelines
.UE .
.SH COPYRIGHT
pkgmk (pkgutils) is Copyright (c) 2000-2005 Per Liden and Copyright (c) 2006-2022 CRUX team (http://crux.nu).
pkgmk (pkgutils) is licensed through the GNU General Public License.
Read the COPYING file for the complete license.