Re: Why does utime() exist?

["Theodore Y. Ts'o" <tytso _at_ MIT.EDU>]

   Date: 	Sat, 19 Aug 2000 11:22:10 +0200
   From: Julien Oster <joster _at_ soft-research.de>

   Why the heck does utime() exist? I could understand it, if it would only
   have a filename as argument and issuing it would change the access and/or
   modification time to the current time - also known as "touch"ing files.

Because you want to be able to restore the access and modification times
when (a) unpacking a tar file, (b) using rsync -t, or (c) mirroring an
FTP directory.  This is in turn necessary because various programs like
make depend on the modification time being correct.

   Is it safe to disable it? It makes life a little harder for system
   administrators concerned about security...

You'll violate posix and confuse various programs depend on the
modification times being correct.

Any programs which depend on modification or access times for security
purposes are broken.  You can use the inode change (ctime) field for
various security purposes --- various games like rogue have used this to
try to keep people from cheating by saving and restoring save files ---
but in general even that's not such a hot idea.

						- Ted

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