Comment # 16 on bug 1165351 from Franck Bui

(In reply to Thomas Blume from comment #15)
>          return (tbsize = (int)rl.rlim_max);
> 
> seems to be a bit excessive.
> But I'm not sure how else to determine a good value.
> Thorsten, would be changing this to the soft limit appropriate, e.g:
> 
>          return (tbsize = (int)rl.rlim_cur);
> 
> ?

Indeed that was my thinking too and it's actually how glibc implements
getdtablesize(3). It looks like there might be a bug here therefore I would
suggest to send a patch upstream that make the code use the soft limit.

But that won't be sufficient unfortunately because PID1 initializes the rlimits
of its child *after* calling initgroups(3). Therefore the soft limit will still
be the one used by PID1 which is still equal to the hard limit.

I'll send a patch to upstream to attempt to fix it.