[Toybox] [PATCH 1/2] xargs: fix kernel builds.

[Rob Landley]

On 10/14/19 3:53 PM, enh via Toybox wrote:
> It turns out that findutils xargs almost always uses an artificially low
> limit of 128KiB. You can observe this with --show-limits (which I
> refrained from adding to toybox since I believe it's only useful if
> you're debugging a broken xargs).

The kernel guys' decision not to give us a way to query this is wrong, by the
way. (I'm honestly tempted to whack-a-mole based on queried kernel version in
portability.h at this point. It'd never work for macos and freebsd though...)

> I think an alternative fix for all this would be to go back to counting
> the cost of the (char *)s, but separate the -s limit from the "system"
> limit --- that way we could have the same behavior as findutils xargs
> for explicit values of -s (which we all seem to agree should *not*
> include the cost of the (char *)s), but also not accidentally overrun
> the actual system limits when we do count the (char *)s. That's more
> complicated though, and findutils' "128KiB is enough for anyone"
> behavior is demonstrably "good enough", so let's go with that for now.

Are you building this on a kernel that _does_ have the 128k limit? (Which was
lifted in 2.6.22 which came out July 8, 2007?) Otherwise a near miss of 128k
shouldn't cause a problem...?

> Tested by building an Android common kernel with toybox xargs, which
> failed before.

Sigh, it built upstream -git. :P

> Bug: http://b/140269206

What's the translation URL to see this externally again? (I need to add that to
the FAQ.)

(Sorry, my plane back to Austin leaves in two and a half hours, off to the
airport. Probably just apply your stuff verbatim when I get home but I gotta go
now.)

Rob