RPM can now be used to build packages for the Intel i386, the Digital
Alpha running Linux, and the Sparc. It has been reported to work
on SGI's and HP workstations as well. There are several features that
make building packages on all platforms easy. The first of these is
the ``optflags'' directive in the
/etc/rpmrc. It can be used to
set flags used when building software to architecture specific values.
Another feature is the ``arch'' macros in the spec file. They can be used
to do different things depending on the architecture you are building on.
Another feature is the ``Exclude'' directive in the header.
The following is part of the spec file for the ``fileutils'' package. It is setup to build on both the Alpha and the Intel.
Summary: GNU File Utilities Name: fileutils Version: 3.16 Release: 1 Copyright: GPL Group: Utilities/File Source0: prep.ai.mit.edu:/pub/gnu/fileutils-3.16.tar.gz Source1: DIR_COLORS Patch: fileutils-3.16-mktime.patch %description These are the GNU file management utilities. It includes programs to copy, move, list, etc, files. The ls program in this package now incorporates color ls! %prep %setup %ifarch alpha %patch -p1 autoconf %endif %build configure --prefix=/usr --exec-prefix=/ make CFLAGS="$RPM_OPT_FLAGS" LDFLAGS=-s %install rm -f /usr/info/fileutils* make install gzip -9nf /usr/info/fileutils* . . .
In this example, you see how the ``optflags'' directive is used from
/etc/rpmrc. Depending on which architecture you are building
on, the proper value is given to
RPM_OPT_FLAGS. You must patch
the Makefile for your package to use this variable in place of the
normal directives you might use (like
-O2). You can
get a better feel for what needs to be done by installing this
source package and then unpacking the source and examine the Makefile.
Then look at the patch for the Makefile and see what changes must be
%ifarch macro is very important to all of this. Most times you
will need to make a patch or two that is specific to one architecture
only. In this case, RPM will allow you to apply that patch to just
one architecture only.
In the above example, fileutils has a patch for 64 bit machines. Obviously,
this should only be applied on the Alpha at the moment. So, we add
%ifarch macro around the 64 bit patch like so:
This will insure that the patch is not applied on any architecture except the alpha.
%ifarch axp %patch1 -p1 %endif
So that you can maintain source RPMs in one directory for all platforms, we have implemented the ability to ``exclude'' packages from being built on certain architectures. This is so you can still do things like
and have the right packages build. If you haven't yet ported an application to a certain platform, all you have to do is add a line like:
rpm --rebuild /usr/src/SRPMS/*.rpm
to the header of the spec file of the source package. Then rebuild the package on the platform that it does build on. You'll then have a source package that builds on an Intel and can easily be skipped on an Alpha.
Using RPM to make multi-architectural packages is usually easier to do than getting the package itself to build both places. As more of the hard packages get built this is getting much easier, however. As always, the best help when you get stuck building an RPM is to look a similar source package.