Earnestly/makepkg_overview.rst

## makepkg_overview.rst

      
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              makepkg_overview.rst
            
          
    A Brief Tour of the Makepkg Process: What Makes a Pacman Package

Introduction

This is a terse document covering the anatomy of a package built for the pacman package manager.
The following example commands can mostly run verbatim to manually create a package without makepkg.
Building


build()
This is used for the creation and generation of needful resources and files. This function will create the src directory which is referred to via the $srcdir variable.
A typical procedure for most projects might look like this:


mkdir src
# Extract the source into src
cd src
./configure --prefix=/usr
make
Installation


package()
The separation of build and installation happens here. Fakeroot is used to maintain appropriate permissions while not actually running as root. That is, the facade of root permission is maintained so long real root privilege is not needed.


mkdir pkg
cd src/program
fakeroot -- make DESTDIR=../../pkg install
Metadata

The meat of the data pacman depends on is now generated, this includes a simple key value pair file called .PKGINFO and an "mtree", the .MTREE.
A .PKGINFO is just a simple collection of what one would express in the PKGBUILD, almost exactly. Keys with multiple entries are simply repeated.
cd pkg
cat << EOF > .PKGINFO
pkgname = $pkgname
pkgver = $pkgver-$pkgrel
pkgdesc = $pkgdesc

url = $url
license = $license

builddate = $(date -u '+%s')
size = $(du -sb --apparent-size | awk '{print $1}')

arch = $(uname -m)

depend = libfoo
depend = libbar
depend = libbaz

makedepend = buildlibfoo
makedepend = buildlibbar
makedepend = buildlibbaz
EOF
An mtree is essentially a way to generate a map of a directory structure with all kinds of attributes included, such as permissions, uids, etc. This allows pacman to easily know what the attributes should be so that any issues can be cross-checked when using the -Qk option.
Bsdtar is then used to generate the .MTREE file. This disables !all of the attributes and then enables a selected few.
When creating the mtree, the .PKGINFO file needs to be first in the archive.
cd pkg
fakeroot -- env LANG=C bsdtar -czf .MTREE --format=mtree --options='!all,use-set,type,uid,gid,mode,time,size,md5,sha256,link' .PKGINFO *
Package

All that remains is to generate a tarball of our package. We use fakeroot again as with everything during the package phase.
cd pkg
fakeroot -- env LANG=C bsdtar -cf - .MTREE .PKGINFO * | xz -c -z - > $pkgname-$pkgver-$pkgrel-$arch.tar.xz
Example

#!/bin/sh --
# Basic makepkg which just creates a package for antimicro, built from git.

# Because I don't do any error handling, just bail if any command fails for
# any reason.
set -o errexit

startdir=$PWD
srcdir=$startdir/src
pkgdir=$startdir/pkg

# The pkgrel just indicates the version of the build itself, independent of
# the pkgver, although a pkgver bump resets the pkgrel to 1.
pkgrel=1
arch=$(uname -m)

# Check for all dependencies.  This command will return any which are
# missing, each one on a newline.
pacman -T cmake qt5-tools libxtst qt5-base sdl2 libxkbcommon-x11

# Build.
mkdir -p "$srcdir"
cd "$srcdir"
git clone https://github.com/AntiMicro/antimicro

cd antimicro

# No hyphens allowed in the version.
pkgver=$(git describe --long --tags | sed 's/^v//; s/\([^-]*-g\)/r\1/; s/-/./g')
cmake -DMAKE_INSTALL_PREFIX=/usr -DUSE_SDL2=ON
make

# Installation.
mkdir -p "$pkgdir"
fakeroot -- make DESTDIR="$pkgdir" install

# Package.
cd "$pkgdir"
cat <<! > .PKGINFO
pkgname = antimicro-git
pkgver = $pkgver-$pkgrel
pkgdesc = map keyboard and mouse actions to gamepad buttons, inspired by qjoypad
url = https://github.com/AntiMicro/antimicro
builddate = $(date -u +%s)
packager = Unknown Packager
size = $(du -sb --apparent-size "$pkgdir" | awk '{print $1}')
arch = $arch
license = GPL
conflict = antimicro
provides = antimicro
depend = libxtst
depend = qt5-base
depend = sdl2
depend = libxkbcommon-x11
makedepend = cmake
makedepend = qt5-tools
!

fakeroot -- env LANG=C bsdtar -czf .MTREE --format=mtree --options='!all,use-set,type,uid,gid,mode,time,size,md5,sha256,link' .PKGINFO *
fakeroot -- env LANG=C bsdtar -cf - .MTREE .PKGINFO * | xz -c -z - > "$startdir"/antimicro-git-"$pkgver"-"$pkgrel"-"$arch".pkg.tar.xz

# Test.
cd "$startdir"
namcap -m antimicro-git-"$pkgver"-"$pkgrel"-"$arch".pkg.tar.xz