Re: [PATCH] Cygwin: Make 'ulimit -c' control writing a coredump

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Jun 15 12:40, Jon Turney wrote:
> On 15/06/2022 12:21, Jon Turney wrote:
> > Factor out pre-formatting a command to be executed on fatal signal, and
> > use that for both error_start (if present in the CYGWIN env var) and for
> > 'dumper'.
> > 
> > Factor out executing that command, so we can use it from try_to_debug()
> > and when a fatal signal occurs.
> > 
> > Because we can't control the size of the core dump written by that, only
> > invoke dumper if the core file size limit is unlimited.
> > 
> > Otherwise, if that limit is greater than 0, we will write a .stackdump
> > file, as previously.
> > 
> > Change the default limit from unlimited to 1 MB, to preserve that
> > existing behaviour.
> 
> Maybe this design tries too hard not to change anything and instead we
> should:
> 
> keep default ulimit -c as unlimited
> 
> ulimit 0     write nothing
> ulimit <=4K  write a .stackdump [*]
> ulimit >4K   write a .core

Sounds good.

> In cases where we wrote something, check afterwards if it's bigger than the
> ulimit and if so, remove it.
> 
> (Maybe this still loses if e.g. 1MB of disk space remains, ulimit is 2MB,
> actual size of coredump is 3MB, since we'll end up with a partial coredump
> when we shouldn't have written anything, but maybe that's what's supposed to
> happen?)

If disk space is low, shit happens.


Corinna