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[Python-Dev] doc for new restricted execution design for Python

Greg Ewing greg.ewing at canterbury.ac.nz
Thu Jun 29 02:01:43 CEST 2006 
Jim Jewett wrote:

> IMHO, I would prefer that it limit disk consumption; a deleted or
> overwritten file would not count against the process, but even a
> temporary spike would need to be less than the cap.

The problem is that there's no easy way to reliably measure
disk consumption by a particular process, particularly on
Unix. For example, os.unlink() doesn't necessarily free
the space used by a file -- there could be other links to
it, or the same or another process may hold another file
descriptor referencing it.

Another problem is that Unix files can have "holes" in
them, e.g. if you create a file, seek to position
1000000, and write a byte, you're not using a megabyte
of disk.

Accounting for all these possibilities reliably would
be very complicated, and maybe even impossible to get
exactly right.

--
Greg
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