The RTEMS Source Builder is a stand alone tool based on another tool called the
SpecBuilder written by Chris Johns. The SpecBuilder was written around 2010
for the RTEMS project to provide Chris with a way to build tools on hosts that
did not support RPMs. At the time the RTEMS tools maintainer only supported
spec files and these files held all the vital configuration data needed to
create suitable tool sets. The available SRPM and spec files by themselves
where of little use because a suitable
rpm tool was needed to use them. At
the time the available versions of
rpm for a number of non-RPM hosts were
broken and randomly maintained. The solution Chris settled on was to use the
spec files and to write a Python based tool that parsed the spec file
format creating a shell script that could be run to build the package. The
approach proved successful and Chris was able to track the RPM version of the
RTEMS tools on a non-RPM host for a number of years.
The SpecBuilder tool did not build tools or packages unrelated to the RTEMS Project where no suitable spec file was available so another tool was needed. Rather than start again Chris decided to take the parsing code for the spec file format and build a new tool called the RTEMS Source Builder.