Chapter 7. Building packages

The following sample specfile provides an example of its major components:

Name: testpackage     # Package name.
Version: 1
Release: 1
Source: test-1.tar.gz
Repository(pgpkeys.txt): http://www.example.com/repository

%package
Requires: glibc

This is a test package.

%package doc

Documentation for the <b>test</b> package.
%begin
%setup

%begin build
%{__make}

cc -o hello hello.c

%begin install

%{__make} install DESTDIR="$__installdir"

%post
/sbin/ldconfig

%postun
/sbin/ldconfig

%files
%{_bindir}/*
%{_libdir}/*

%files doc
%doc README NEWS COPYING

The specfile has a well-defined, structured layout. It begins with the “build header” section. The build header runs from the beginning of the specfile until the first “%package” section. The build header provides the general information about this application.

The build header is followed by one or more package declaration sections. Each package declaration begins with the “%package” line. Simple applications will only one package declaration. Large, complex, applications that consists of a main package, and subpackages, will have additional “%package” lines, one for each subpackage.

The build header, and the package sections, contain all the information lpbuild needs to begin building the application. After the package sections comes the shell script, or scripts, that actually build the application and install it into a temporary staging area, an installation image tree. The “%begin” line marks the beginning of each shell script. lpbuild runs the system's shell interpreter to execute the shell script. The shell scripts should unpack the source code, compile it and install it.

Only one “%begin” section is required, but usually there's more than one. Multiple “%begin” sections are very useful when developing the specfile itself. The process of building and installing an application is rarely straightforward. It is nearly impossible to create a complete specfile from scratch, in one shot. Multiple “%begin” sections allow a specfile's construction one step at a time. By default, lpbuild executes each “%begin” section, one after the other. Optional command line parameters can instruct lpbuild to run only a specific, single, “%begin” section, allowing individual portions of the overall build script to be debugged, one piece at a time.

The “%begin” sections are ordinarily scripts, which are executed by /bin/sh, except that lpbuild does macro expansion on each shell script, before it gets executed. Macros, like “%{name}” are explained later in Section 13, “Macros”.

The specfile ends with one or more file manifest sections. These sections contain an explicit manifest of files that the shell scripts placed in the installation image directory. Although the application gets installed in a separate, dedicated directory, an explicit file list is still required. Furthermore, there will be additional %files sections when subpackages are built. A separate %files section appears for the main package and each subpackage.