Re: glibc at the Toolchains microconference at LPC 2019

[Zack Weinberg <zackw@panix.com>]

On Thu, Jun 27, 2019 at 5:39 AM Dmitry V. Levin <ldv@altlinux.org> wrote:
>
> On Wed, Jun 26, 2019 at 05:04:52PM -0400, Carlos O'Donell wrote:
> [...]
> > Could you please review the language here:
> > https://sourceware.org/glibc/wiki/Consensus#WIP:_Kernel_syscalls_wrappers
>
> I suggest adding that there is no need to add wrappers for those syscalls
> that already have dedicated libraries.
>
> For example, such multiplexers as bpf(2) and keyctl(2) already have
> dedicated libraries (libbpf and libkeyutils, respectively) that provide
> APIs on top of these raw syscalls.

I specifically disagree with this.  The existence of these dedicated
libraries does not mean that there is no need for a minimal wrapper in
the C library.  In fact, providing a minimal wrapper in the C library
would make the implementation of dedicated libraries easier, since
they can concentrate on designing their higher-level API rather than
wasting engineering effort on system call wrappers.  glibc has already
done all of the low-level work necessary.

I am a little disappointed to see that Linux is still inventing new
multiplexed system calls, though.  I thought that was demonstrated to
be a bad idea back in the days of __NR_ipc.

zw