Re: Process exit notifcation in a kext
Re: Process exit notifcation in a kext
- Subject: Re: Process exit notifcation in a kext
- From: Bogdan Harjoc <email@hidden>
- Date: Fri, 18 Jun 2010 13:00:06 +0300
On Thu, Jun 17, 2010 at 9:24 PM, Terry Lambert <email@hidden> wrote:
>> I'd like to ask is this approach is correct: call
>> proc_find(pid) which takes a reference to the proc_t, and then
>> proc_rele(pid) when the exit notification from kqueue comes. This
>> avoids the race, but will the process exit while I am holding a
>> reference to it ?
> In addition, you have no guarantee that the locking order will happen the
> way you want it to, i.e. there is a race in acquiring the lock on the
> process list between you doing the pfind() and the process ID being reused
> between the time you decide a given PID is interesting to you and the time
> that the process reference is obtained on a process with that PID, such that
> it may not be the process you found interesting by the time you have the
> reference. It's undefined, which is why it's bad to use PID as a unique
> identifier for security purposes.
True, because I would call pfind() in a callback coming from
tcp_input() (and not from a user process). I was hoping for a way to
tag a process (like one can tag mbuf's), is this somehow possible ?
> -- Terry
Thanks again,
Bogdan
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