Re: Why does SVN + apache try to close non existing file descriptors?

On Wednesday 12 March 2008, Jon Bendtsen wrote:
> Q) why brute force close all files?
> a) ask the kernel to close all my open files
> b) ask the kernel which files do I have open and then close only those
> c) remember what files i have open and then close only those

This problem may sound easy but is quite tricky to solve: there's no portable
solution for a) and b), and c) is not reliable. For example, on Linux I think
there's no way for a), and b) would most likely have to rely on
analyzing /proc/*/fd. But this won't work on systems like FreeBSD or Mac OS X
which don't have /proc.

This is why several UNIX applications do the brute force way. But it may be a
good idea to limit it. It's highly unlikely that SubVersion would have more
than say 128 file handles open, with a safety factor let's make that 1024. If
by chance there really ARE more than 1024 file descriptors open you propably
have bigger problems than not having all file descriptors closed ;-)

Marc

-- 
Marc Haisenko
Comdasys AG
Rüdesheimer Str. 7
80686 München
Germany
Tel.: +49 (0)89 548 433 321
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