dhcpcd-discuss

Thank you for your consideration.

> I would hope that system packagers would test dhcpcd before blindly comitting it for their downstreams to use.

One problem is that it can break not just on dhcpcd update, but also on changes in libc and kernel. Libc may use different syscalls depending on kernel version. Kernel can be decoupled from Linux distribution in case of containers. Also, users may want to opt for newer kernel for hardware support. It's understandable that distribution maintainers don't test every update on every possible combination of relevant software that users may have. And usually they don't have to, because APIs are backwards compatible. In this case, it's just the syscall filter that breaks compatibility.

Now when breakage does get discovered during testing, the options are:
delay update (of dhcpcd, libraries or kernel) until it's investigated and fixed upstream,
develop a downstream patch,
disable syscall filters in the build.
I believe, there should be another option. If syscall whitelist was modifiable at runtime and the program reported blocked syscalls, it would be easier to fix, and it would be fixable by end-users and administrators who have a combination of software that was not explicitly tested.