Question

I’d like to use setcap, part of libcap-bin, on an embedded Linux device. I use buildroot and see that it has the packages libcap and libcap-ng available, but not libcap-bin.

I googled around but cannot find the source for libcap-bin to produce the setcap binary for the ARM target board.

On Ubuntu I just install with:

sudo apt-get install libcap-bin

Where can I get the source and how can I build libcap-bin for my ARM board?

Answer 1

As others have explained: you can’t expect a 1:1 match between the packages you’re seeing in your Ubuntu/Debian distribution and the packages you’re seeing in Buildroot.

Ubuntu/Debian packages take source packages (in this case libcap) and create multiple binary packages from them, in order to allow you to install only the library, or the library + development files, or the library + programs, etc. For example, look at http://packages.ubuntu.com/source/quantal/libcap2, which is the reference page for the libcap2 source package: it gives you the list of binary packages generated in Ubuntu from this source package.

On the other hand, in Buildroot, there is only the concept of source packages. One package in Buildroot == one tarball from a given software component. Therefore, there is only package/libcap. At the moment, package/libcap/libcap.mk is written to only install the library because no-one needed the setcap and getcap programs. But you can extend package/libcap/libcap.mk (and possibly package/libcap/Config.in) to enable the compilation of the programs as well. As another commenter noted, you will need to add attr as a dependency (though the commenter wrongly said that Buildroot didn’t had attr: it does have it, see package/attr).