Date: Wed, 13 Jun 2007 20:20:47 +0200 From: Joerg Sonnenberger <joerg@britannica.bec.de> To: freebsd-hackers@freebsd.org, hackers@freebsd.org Subject: Re: Using shell commands versus C equivalents Message-ID: <20070613182046.GC8427@britannica.bec.de> In-Reply-To: <Pine.LNX.4.43.0706131023360.25469@hymn01.u.washington.edu> References: <20070613162559.GA5093@britannica.bec.de> <Pine.LNX.4.43.0706131023360.25469@hymn01.u.washington.edu>
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On Wed, Jun 13, 2007 at 10:23:36AM -0700, youshi10@u.washington.edu wrote: > Should I briefly lock (flock) the file when running open/fstat/fchmod then > to avoid issues? This may become a problem as pkg_*/make becomes more > parallelized (another student's goals for his SoC project). Looking does not change the issue. The problem here to protect against is that a process renames a file between the stat and the chmod. See the classic tmp file class of security vulnerabilities. > Needless to say, pkg_* is by no means threadsafe in its current form > though. It uses some global vars that are currently not mutex locked, and > this type of file access is another issue (I wonder if spinlocking or > sleeping waiting for flock to finish would be better in this case). I'm perfectly aware of the state of pkg_install. I also believe that it is a bad idea to parallelise it, but I don't want to argue with FreeBSD/Ports about that. Joerg
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