IMFS / memfile bug?

Till Straumann strauman at SLAC.Stanford.EDU
Tue Sep 17 01:50:49 UTC 2002

Hi Joel.

Joel Sherrill wrote:

>Till Straumann wrote:
>>Sorry, if this is already known - it seems I can't access the bug
>>tracking system
>>right now.
> had a security breach.  It is undergoing an
>audit and upgrade.  :(
Sorry to hear that - what a nuisance :-(

>>There seems to be bug in the IMFS/memfile implementation:
>>Memory for files who are closed after removal (e.g. created
>>by tmpfile()) seems to be never released...
>>Is anybody working on IMFS?
>Jennifer and I wrote the IMFS.  We fix bugs as they are reported.  
>Please send a test case and we will look into it.
IMO it's easier to look at the source than producing a test case -
you'll see it immediately. I came across it when tmpfile() ate
up all my memory.

tmpfile() opens a file, unlink()s it and returns the open file to the
caller. The file is supposed to be physically removed upon close().

Now, memfile_rmnod() [correctly] refuses to release the memory
occupied by an open file. However, there should be a check in
memfile_close() for this case [i.e. last close of a file that has
already been unlinked from a directory]. Fixing this shouldn't be
hard but I don't have the time right now to study the details
which you and Jennifer are more familiar with anyways...

Kind regards
-- Till


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