Bastien ROUCARIES wrote: > If chdir is a problem, why not using a heavy weight approach (better safe than > sorry particularly if gnulib is used for a lot of project): > - fork and exec an helper for name resolution > - pass fd using a socket > > It is really heavy but it is on the safe side
Expensive indeed. We've used that approach as a fallback in a couple of other areas (see gnulib's lib/savewd.c and its uses in coreutils: http://git.sv.gnu.org/cgit/coreutils.git/commit/?id=b67faf329ce), but never in functions as heavily used as openat, statat, chownat, etc. Adding a single "stat" call to the inner loop behind "chown -R ..." can add about 25% to the run-time duration. Adding a fork may be prohibitive. The trouble is that we cannot resort to using "fork" only when the faster f?chdir-based implementation fails, since once it has failed it is too late. If someone tries this, I'll be interested to see the cost it incurs.
