Re: compat: autofs v5 packet size ambiguity - update

From: Linus Torvalds
Date: Wed Feb 22 2012 - 20:57:13 EST


On Wed, Feb 22, 2012 at 5:48 PM, Ian Kent <raven@xxxxxxxxxx> wrote:
>
> Sorry, I think your wrong this time.

Well, that would be good, actually. Doing the test itself at mount
time is certainly the simpler approach.

>> The autofs "mount" is done by fork + execve("mount").
>
> It's done like this when mounting things inside an already mounted
> indirect autofs mount or when mounting things on autofs direct mount
> triggers but, in version 5, mount(2) has always used to mount autofs
> file systems.

Is that true for legacy autofs daemons too that distros ship? Because
those are the ones we'd be fighting..

Because when I do

git grep '\<mount[ ]*(' -- '*.[ch]'

(that's a space and a tab in that pattern) on the autofs-4.1.4 sources
I downloaded, I don't see a single call to mount. But I do see
spawning of PATH_MOUNT. And one of them is with "-t", "autofs".

So at least in the last version of autofs4, it was executing the
external "mount" program, not using mount(2).

Linus
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