Make a unique filesystem path, without creating the file

Chris Angelico rosuav at gmail.com
Mon Feb 22 14:04:02 EST 2016


On Tue, Feb 23, 2016 at 5:39 AM, Jon Ribbens
<jon+usenet at unequivocal.co.uk> wrote:
> On 2016-02-22, Chris Angelico <rosuav at gmail.com> wrote:
>> On Tue, Feb 23, 2016 at 5:17 AM, Jon Ribbens
>><jon+usenet at unequivocal.co.uk> wrote:
>>> Weeeeeell, I have a lot of sympathy for that point, but on the other
>>> hand the whole concept of UUIDs ("import uuid") is predicated on the
>>> opposite assumption.
>>
>> Not quite opposite. Ethan is asserting that you cannot be *certain*
>> without actually checking the FS; the point of UUIDs is that you can
>> be fairly *confident* that there won't be a collision. There is a
>> nonzero probability of accidental collisions, and if an attacker is
>> deliberately trying to _force_ a collision, it's most definitely
>> possible. So both views are correct.
>
> I was under the impression that the point of UUIDs is that you can be
> *so* confident that there won't be a collision that for all practical
> purposes it's indistinguishable from being certain.

Maybe, if everyone's cooperating. I'm not sure how they fare in the
face of malice though.

ChrisA


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