Re: statx syscall support

[Rich Felker <dalias@libc.org>]

On Wed, Dec 13, 2017 at 10:54:07AM +0100, Daniel Cegiełka wrote:
> hi,
> is there any plan for statx syscall support in musl?
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/stat.h?h=v4.15-rc3
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/samples/statx/test-statx.c?h=v4.15-rc3

Nothing specific right now. The syscall number will of course be added
to syscall.h and available for direct use, but not much use without a
header defining the type. Of course <linux/statx.h> or whatever should
work assuming they don't define types that clash with libc.

In the long term, the statx interfaces may be useful for implementing
the POSIX stat function, especially on some archs (mainly mips) where
the existing stat syscalls are broken and need patching-up in
userspace. There's a vague future idea for a "musl 2 ABI" somewhere
down the line with clean, extensible, arch-independent definitions for
all the structs (and translation to/from kernel definitions in
wrappers) and using statx would certainly be helpful for that (but of
course would need fallbacks for older kernels unless this happens so
far in the future that older kernels are not relevant). All this would
be "under the hood", though, not as the primary public interface.

Rich