On Jun 11 11:17, Christopher Faylor wrote: > On Tue, Jun 11, 2013 at 05:04:46PM +0200, Corinna Vinschen wrote: > >I don't see how do this without calling path_conv, though. You have to > >perform the full conversion on the parent path, with symlinks and > >everything to get the right result. > > Yes, but it is a HUGE stack hit to call path_conv recursively here.
Shouldn't that be much reduced by the fact that the temporary buffers used by path_conv are tmp_pathbuf buffers? Originally, when we started with 1.7, we had all those 64K buffers on the stack and thus a lot of spurious crashes due to stack overflow. But since using tmp_pathbuf buffers we got rid of those. Maybe we should contemplate the idea to raise the maximum number of tmp_pathbuf buffers to accommodate situations we're not aware of at this point in time. > >However, I'm rather impressed by the low impact of this change. I moved > >the check_parent setting so it's only set when a slash occurs, and then > >I made a couple of runs building coreutils. As you know, GCC uses .. > >paths a lot. The performance hit is almost unnoticable: 72.3 seconds > >without, 73.4 seconds with the patch. > > If we are considering doing this, then couldn't we somehow just avoid > eliminating "/.." until after the path is fully parsed and then collapse > all of them in one final loop? Also, don't we have the same problem for > foo/./bar? We change that to foo/bar but foo may not exist. The problem with .. is that a path component disappears while normalizing the path, without checking it's existence. Therefore foo/./bar is no problem here, because the final patch still contains foo and thus it's existence will be checked anyway. I may be missing something, but if we don't remove .. and . from the path right at the start of path_conv, then we have exactly the problem which so far kept us from doing the check: A . or .. component spoils the mount_table->conv_to_win32_path path, and it might (I'm *not* sure) break the sym.check call as well. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
