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Beginner's Guide to Using Novell SUSE Linux's Build Utility

Novell Cool Solutions: Feature
By Paul MacKay

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Posted: 23 Mar 2005
 

Introduction

"The RPM Package Manager (RPM) is a powerful command line driven package management system capable of installing, uninstalling, verifying, querying, and updating computer software packages."1

RPM is now considered the 'standard' for application and system packaging by most Linux distributions. Novell SUSE Linux is one of those distributions that has standardized on RPM.

The design goals for RPM are to:

  1. make it easy to get packages on and off the system
  2. make it easy to verify that a package was installed correctly
  3. make it easy for the package builder
  4. make the build process start with the original source code
  5. make it work on different computer architectures

There are many "How-to's" and tutorials describing how to create RPMs (see Resources). However, creating RPMs in a clean build environment and in a consistent reproducible way, requires more effort than should be necessary.

Novell SUSE Linux provides a utility called build that streamlines the RPM creation process and ensures configuration and system uniformity. It does this in an isolated chroot environment containing only the required packages necessary to create your RPM.

This tutorial describes how to use the build utility to easily create RPMs for Novell SUSE Linux.

Where to Begin

To use build you must first install build.rpm. The build.rpm package is available via YaST or from Novell SUSE Linux's download site (see Resources for download information).

The build.rpm package includes the following files:

/usr/bin/build
/usr/bin/unrpm
/usr/lib/build/init_buildsystem
/usr/lib/build/pac_unpack
/usr/share/doc/packages/build
/usr/share/doc/packages/build/README
/usr/share/man/man1/build.1.gz

In addition to the ?/usr/bin/build? utility, build.rpm contains a useful RPM-related command called ?/usr/bin/unrpm.? The unrpm command is a simple script to ?expand? the contents of an RPM in the current directory (using rpm2cpio etc.).

Once you have installed build.rpm you will need either to mount a Novell SUSE Linux DVD (or DVD ISO image) or create a directory containing the contents of the DVD. If you only have CDs, then copy all of the contents of the CDs into a directory.

Creating a local directory containing the contents of the DVD is highly recommended since it is far easier to update RPMs in a local directory than it is on a DVD:)

To create such a directory, copy everything under the DVD's top level directory using the following command:

cp -a /media/dvd/* <desired-directory>

The RPMs are used to create a reproducible build environment. The DVD or the directory containing the RPMs must also include any additional RPMs needed to satisfy your packages' build requirements that are not part of a standard Novell SUSE Linux release.

By default, the RPMs are assumed to be located on a DVD that is mounted in the following directory:

/media/dvd

To override this default location, you need to set an environment variable named BUILD_RPMS to point to the directory containing the RPMs. Another way to specify where the RPMs are located is by using the --rpms option when invoking the build command.

build --rpms /work/9.2

How to Use the build Utility

To use build you must be root (root is required to use the chroot command). The chroot environment, by default, is created in the following location:

/var/tmp/build-root

The build utility takes as an argument an RPM spec file or a source RPM file (if no argument is specified, build assumes that the current directory contains a spec file and a source tar ball). If an RPM spec file is specified, a tar ball containing the source files is expected to be in the current directory. For those new to RPMs and RPM spec files, please look at the references at the end of this tutorial.

The key to creating an RPM spec file that build can use is to add one extra tag to the spec file. The special tag is BuildRequires, which lists all of the RPMs that are required to be installed in order for the source package to compile.

The build command initializes the build environment by installing all of the required packages necessary to compile the given RPM package. build then copies all of the source files, patch files and the rpm spec file into the chroot build area. The new build area becomes the "new" root in which build will operate.

The successful result of executing build is a binary RPM (a repackage source rpm is also generated) created in:

/var/tmp/build-root/usr/src/packages/RPMS

Enabling your application to be built using build ensures a reproducible build environment that doesn't get corrupted by the host's environment and vice-a-versa.

To test your newly created RPM, simply chroot into the build environment and install your RPM package using the standard rpm command.

Example Using build

A simple way to see how to use the build utility is to use build to create the GNU hello world RPM binary package.

  1. Get the appropriate hello--.src.rpm (for the purposes of this example I will use hello-2.1.1-311.src.rpm) by downloading it from the source directory for the Novell SUSE Linux version (e.g. 9.1, 9.2, SLES9, NLD9) you are using for RPMs referenced by build.rpm.


  2. Create a directory called hello and change into it:
  3. mkdir hello cd hello
  4. Use the unrpm command to look at the contents of the source RPM:
  5. unrpm hello-2.1.1-311.src.rpm
  6. The directory will now contain the following files:
  7. hello-1.3.dif hello-2.1.1-311.src.rpm hello-2.1.1.tar.gz hello.spec
  8. If you look in the hello.spec file you will see the BuildRequires tag that build.rpm uses to install all specified RPMs into a build environment:

    ... BuildRequires: aaa_base acl attr bash bind-utils bison bzip2 coreutils cpio cppcracklib cvs cyrus-sasl db devs diffutils e2fsprogs file filesystem fillup findutils flex gawk gdbm-devel glibc glibc-devel glibc-locale gpm grep groff gzip info insserv less libacl libattr libgcc libnscd libselinux libstdc++ libxcrypt libzio m4 make man mktemp module-init-tools ncurses ncurses-devel net-tools netcfg openldap2-client openssl pam pam-modules patch permissions popt procinfo procps psmisc pwdutils rcs readline sed strace syslogd sysvinit tar tcpd texinfo timezone unzip util-linux vim zlib zlib-devel autoconf automake binutils gcc gdbm gettext libtool perl rpm ...


  9. Now switch user to root (su command)


  10. Issue the following command:
  11. build --rpms /work/dvd/9.2
  12. The build command will create, by default, an isolated build environment in
  13. /var/tmp/build-root
  14. If all goes well you will see the following message after build has completed:
  15. Wrote:
    /usr/src/packages/SRPMS/hello-2.1.1-311.src.rpm
    Wrote: /usr/src/packages/RPMS/i586/hello-2.1.1-311.i586.rpm
    Executing(%clean): /bin/sh -e /var/tmp/rpm-tmp.2137
    + umask 022
    + cd /usr/src/packages/BUILD
    + cd hello-2.1.1
    + '[' /var/tmp/hello-2.1.1-build '!=' / ']'
    + '[' -d /var/tmp/hello-2.1.1-build ']'
    + rm -rf /var/tmp/hello-2.1.1-build
    + exit 0
  16. The created binary and source RPMs are found in:
  17. /var/tmp/build-root/usr/src/packages/RPMS/i586/hello-2.1.1-311.i586.rpm
    /var/tmp/build-root/usr/src/packages/SRPMS/hello-2.1.1-311/src/rpm
  18. If you want to check the installation of your binary RPM you can chroot into the build area and use the rpm command:
chroot /var/tmp/build-root
rpm -ivh /usr/src/packages/RPMS/i586/hello-2.1.1-311.i586.rpm

The RPM should install without any issues.

Conclusion

This tutorial has given a brief overview of Novell SUSE Linux's build utility. Please consult the build man page for addition information and a description of other beneficial command line options.

Using build.rpm is an easy and reproducible way to create binary and source RPMs for Novell SUSE Linux in an isolated build environment. As a side benefit, the isolated environment can also be used to test the installation of your RPMs.

The build.rpm utility can also be used to create RPMs for multiple versions of Novell SUSE Linux on a single system. How to do this is the topic of another tutorial on build.rpm.

Have a lot of fun ...

Resources

FTP site for build.rpm (9.3 version):
ftp://ftp.suse.com/pub/suse/i386/9.3/suse/noarch/

FTP site for build.rpm (9.2 version):
ftp://ftp.suse.com/pub/suse/i386/9.2/suse/noarch/

1The 'Official' site for RPM:
http://www.rpm.org

Software Packaging with RPM:
http://www.linux-mag.com/2004-02/compile_01.html

Building RPM Packages
http://www-uxsup.csx.cam.ac.uk/talks/rpmbuild/rpmbuild.pdf

RPM 101
http://linuxvm.org/present/SHARE99/S9372NFa.pdf


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