Re: [Nmh-workers] mhstore -clobber

[David Levine]

Paul wrote:

> On 2012-09-16 4:50 PM, David Levine wrote:
> > Lyndon wrote:
> >
> >> On 2012-09-16, at 8:42 AM, Lyndon Nerenberg wrote:
> >>
> >>> Well, there's the obvious race condition ...
> >> Sorry, I left out the "NFS" in front of "race."
> > What's the NFS race condition?  If you're talking about
> > old NFS that doesn't support O_EXCL, I'm not willing to
> > jump through hoops for that.
> 
> i don't think it requires nfs in order for it to be a race. granted,
> this code cannot lose a race against itself if coded as open, close,
> fopen, since the file name will be stable and the open uses creat|excl.
> however, some other app could sneak in and get the file opened between
> the close and the fopen, which smells like a security problem. far
> better to do open, fdopen. (i'm thinking now of two of "crontab"'s early
> CERT advisories.)

How is this more dangerous than fopen'ing for write any of my
existing files?

mhstore already has multiple open-closes on an output file
to support gluing together of message/partial's, how is that
different?

David