RPM packaging: A simplified guide to creating your first RPM

The concept of RPM packaging can be overwhelming for first-timers because of the impression a steep learning curve is involved. In this article, I will demonstrate that building an RPM with minimal knowledge and experience is possible. Note that this article is meant as a starting point, not a complete guide to RPM packaging.

ASCII-based Tetris game

For my demonstration, I chose a simple ASCII-based Tetris game, written in C, and I made slight adjustments to ensure a relatively straightforward RPM build. I will use a game called Vitetris as my example, which you can download.

To ensure there are no errors when creating the RPM package, I remove references in the Makefile that change file permissions to root, in order to allow a non-root user to build the RPM. This modification is as follows:

$ cat Makefile |grep 'INSTALL '
INSTALL = install
#INSTALL = install -oroot -groot # non-root users building the rpm won't be able to set this and the RPM build will fail.

Once you have made this change, create a new gzipped tarball with the same name: vitetris-0.57.tar.gz.

Preparing the environment

To install your development environment on a subscribed Red Hat Enterprise Linux (RHEL) 7 system, you need the following repositories to build your RPMs: rhel-7-server-rpms, rhel-7-server-extras-rpms, and rhel-7-server-optional-rpms.

You must have following packages installed:

# yum install -y rpm* gcc gpg* rng-tools

I use rpm* and gpg* because it makes the number of things to remember to install much more manageable.

Compiling the software manually

A large part of success with RPM packaging understanding the software you are working with. First, compiling software manually preferably is done as a non-root user. In this case, I am using the rpmbuilder user.

Start with extracting the gzipped tarball (vitetris-0.57.tar.gz), and then inspecting the README file. In this case, the README file doesn't contain information about compiling your game from source code. As a general rule, open source software written in C is compiled with three steps: configure, make, and make install. However, it is worth just running make on its own to see whether the software will build.

As a non-root user, test to see whether running make is sufficient:

[rpmbuilder@rpm vitetris-0.57]$ make
generating src/src-conf.mk
./src-conf.sh 'cc' '' ''
...
Done.
Now run ./tetris (or make install)

To test the game, simply run ./tetris to see whether the game loads and can be played:

Creating GPG keys

Signing your RPM package adds an extra layer of trust to your packages. Therefore, to create GPG keys as the rpmbuilder user, you will need a session with root access to run rngd (to speed up the generation process) and a session with X11 forwarding as the rpmbuilder user.

As root, run:

# rngd -r /dev/urandom

If you get the following error:

Failed to init entropy source 2: Intel RDRAND Instruction RNG

Try:

# rngd -r /dev/urandom -o /dev/random -f

You must log into the host as rpmbuilder user with X11 forwarding (otherwise, the key generation will fail):

$ gpg --gen-key
...
Please select what kind of key you want:
(1) RSA and RSA (default)
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
Your selection? 1
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
0 = key does not expire
<n> = key expires in n days
<n>w = key expires in n weeks
<n>m = key expires in n months
<n>y = key expires in n years
Key is valid for? (0) 
Key does not expire at all
Is this correct? (y/N) y

GnuPG needs to construct a user ID to identify your key.

Real name: RPM Build User
Email address: rpmbuilder@rpm
Comment: RPM Builder GPG Signing Key
You selected this USER-ID:
"RPM Build User (RPM Builder GPG Signing Key) <rpmbuilder@rpm>"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O
You need a Passphrase to protect your secret key.

...
gpg: depth: 0 valid: 1 signed: 0 trust: 0-, 0q, 0n, 0m, 0f, 1u
pub 2048R/EEF6D9AD 2019-03-02
Key fingerprint = 6ED1 2456 B7ED EEC6 D0DF B870 444A 40A7 EEF6 D9AD
uid RPM Build User (RPM Builder GPG Signing Key) <rpmbuilder@rpm>
sub 2048R/D498F883 2019-03-02

If you need to export the key to be used within satellite for custom software or in your yum repo configuration, use the command:

$ gpg --armor --export
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v2.0.22 (GNU/Linux)

...

Creating the RPM package for Vitetris

To build the RPM, first create the build tree and the spec file and place the source code in the right place:

$ rpmdev-setuptree
$ rpmdev-newspec rpmbuild/SPECS/vitetris.spec
rpmbuild/SPECS/vitetris.spec created; type minimal, rpm version >= 4.11.
$ cp vitetris-0.57.tar.gz rpmbuild/SOURCES/

Add initial details to the spec file

Provide the initial details:

Name:           vitetris
Version:        0.57
Release:        1%{?dist}
Summary:        ASCII based tetris game

License:        BSD
URL:            https://www.victornils.net/tetris/
Source0:        vitetris-0.57.tar.gz

BuildRequires:  gcc

Remove unnecessary sections

• Delete the Requires section, as this software doesn't have any dependencies.
• Delete the %configure section, as this software can be built without configure (keep this if you need configure before you run make).

Add a description

You can add anything you like, but here is a suggestion:

%description
vitetris is a multiplayer ASCII-based Tetris game

Test the initial build

Test the build with the information just provided to see what errors appear:

$ rpmbuild -ba rpmbuild/SPECS/vitetris.spec
...
RPM build errors:
Installed (but unpackaged) file(s) found:
/usr/local/bin/tetris
/usr/local/share/applications/vitetris.desktop
/usr/local/share/doc/vitetris/README
/usr/local/share/doc/vitetris/licence.txt
/usr/local/share/pixmaps/vitetris.xpm

Add a list of files from the previous step to the spec file

You must add the list of files from the previous step to the %files section, as follows:

%files
/usr/local/bin/tetris
/usr/local/share/applications/vitetris.desktop
%doc /usr/local/share/doc/vitetris/README
/usr/local/share/doc/vitetris/licence.txt
/usr/local/share/pixmaps/vitetris.xpm

Notice that %doc was put in front of the README to identify it as an informational document. The RPM will still build without this.

Rerun the build

$ rpmbuild -ba rpmbuild/SPECS/vitetris.spec
Wrote: /home/rpmbuilder/rpmbuild/SRPMS/vitetris-0.57-1.el7.src.rpm
Wrote: /home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm
Wrote: /home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-debuginfo-0.57-1.el7.x86_64.rpm
Executing(%clean): /bin/sh -e /var/tmp/rpm-tmp.AqR4Aq
+ umask 022
+ cd /home/rpmbuilder/rpmbuild/BUILD
+ cd vitetris-0.57
+ /usr/bin/rm -rf /home/rpmbuilder/rpmbuild/BUILDROOT/vitetris-0.57-1.el7.x86_64
+ exit 0

Sign the RPM package

Signing your RPM is as simple as running:

$ rpmsign --addsign /home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm 
Enter pass phrase: Pass phrase is good. 
/home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm:

If you get this error:

You must set "%_gpg_name" in your macro file

Set %_gpg_name with the public key value:

$ gpg --list-keys 
/home/rpmbuilder/.gnupg/pubring.gpg
-----------------------------------
pub 2048R/EEF6D9AD 2019-03-02
uid RPM Build User (RPM Builder GPG Signing Key) <rpmbuilder@rpm>
sub 2048R/D498F883 2019-03-02

$ echo "%_gpg_name EEF6D9AD" >> .rpmmacros

Try again:

$ rpmsign --addsign /home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm
Enter pass phrase: 
Pass phrase is good.
/home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm:

Test an install/uninstall of the RPM as root user

# rpm -i /home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm
warning: /home/rpmbuilder/rpmbuild/RPMS/x86_64/vitetris-0.57-1.el7.x86_64.rpm: Header V4 RSA/SHA1 Signature, key ID eef6d9ad: NOKEY

# /usr/local/bin/tetris

Uninstall the RPM:

# rpm -qa |grep tetris
vitetris-0.57-1.el7.x86_64
=# rpm -e vitetris-0.57-1.el7.x86_64
# /usr/local/bin/tetris
-bash: /usr/local/bin/tetris: No such file or directory

Conclusion

Depending on the software you intend to package, custom RPM packaging can be challenging. In this article, I aimed to do as little as possible to demonstrate that default settings are often enough to build an RPM.

To learn more, see Red Hat's RPM packaging guide.