Re: Re: sysconf(_SC_ARG_MAX) broken in musl.

[Alexander Monakov <amonakov@ispras.ru>]

On Wed, 10 Aug 2016, Rich Felker wrote:
> Has anyone else looked into the issue enough to have a good opinion on
> it, or at least additional information that would add to discussion?

To provide a data point, I've been told that userspace QEmu used to limit the
cumulative args length in a more restrictive way than the kernel (1/4th stack
limit). The observed failure mode was this: xargs running under qemu-user would
build the command line according to what glibc thought would be accepted by the
syscall (based on large stack size), but then the syscall would fail because
qemu-user wouldn't process that many args.

I understand this is not much, since qemu-user is unreliable in other ways, and
this particular issue has been fixed in QEmu regardless, but still I think it
contributes to the general point. Is the concern that 128KB is too low to be
usable? My understanding is that _SC_ARG_MAX is not broken in musl (contrary to
what the subject says), just conservative (in a healthy way in this case imho).

Alexander