Re: RLIMIT_FSIZE and SIGXFSZ

[David Holland <dholland-tech%netbsd.org@localhost>]

On Sat, Nov 16, 2013 at 12:40:22AM -0500, Mouse wrote:
 > The documentation I have (which is consistent across 1.4T, 4.0.1, and
 > 5.2) says that "[a] file I/O operation that would create a file larger
 > that the process' soft limit will cause the write to fail and a signal
 > SIGXFSZ to be generated".  I looked at the code (for 4.0.1, that being
 > what's on the machine I care about at the moment) and this appears to
 > be accurate.
 > 
 > It seems to me it would be more useful to do something like what
 > RLIMIT_CPU does, and generate SIGXFSZ for such operations, but fail
 > them only when the size exceeds the hard limit.  As it stands, the hard
 > limit is useful only as a value the soft limit can't be raised above.
 > ("More useful" to me, at any rate.)

So I think the CPU limit signalling is treated as a special case
because it's pretty useless to deliver a signal whose handler you
can't execute because you're past the CPU limit. Otherwise (all other
limits) you get denied once you reach the soft limit, and I think
that's the way things are intended to work.

I think what you want is an additional signaling threshold that can be
manipulated separately from the limit.

-- 
David A. Holland
dholland%netbsd.org@localhost