From owner-freebsd-hackers@FreeBSD.ORG  Fri Sep  5 19:00:45 2008
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Date: Fri, 5 Sep 2008 22:40:32 +0400
From: Igor Sysoev <is@rambler-co.ru>
To: freebsd-hackers@FreeBSD.org
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Subject: opendir()/closedir()
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Looking at opendir()/readdir()/closedir() sequence via ktrace,
I've seen supposedly useless lseek() syscall just before close().
It's called from closedir():

        _seekdir(dirp, dirp->dd_rewind);        /* free seekdir storage */

It seems that free()ing libc seekdir storage should be done without
calling lseek().

Other strange place for me is stat() before open() in opendir()

        /*
         * stat() before _open() because opening of special files may be
         * harmful.  _fstat() after open because the file may have changed.
         */

What is the case when opening special file may be harmful ?


-- 
Igor Sysoev
http://sysoev.ru/en/