Re: [PATCH 1/2] pid: add pidfd_open()

From: Aleksa Sarai
Date: Thu May 16 2019 - 10:56:10 EST


On 2019-05-16, Christian Brauner <christian@xxxxxxxxxx> wrote:
> On Wed, May 15, 2019 at 10:45:06AM -0700, Daniel Colascione wrote:
> > On Wed, May 15, 2019 at 3:04 AM Christian Brauner <christian@xxxxxxxxxx> wrote:
> > > + if (pid <= 0)
> > > + return -EINVAL;
> >
> > WDYT of defining pid == 0 to mean "open myself"?
>
> I'm torn. It be a nice shortcut of course but pid being 0 is usually an
> indicator for child processes. So unless the getpid() before
> pidfd_open() is an issue I'd say let's leave it as is. If you really
> want the shortcut might -1 be better?

I'd suggest not using negative numbers, and instead reserving them for
PIDTYPE_TGID if we ever want to have that in the future. IMHO, doing

pfd = pidfd_open(getpid(), 0);

is not the end of the world.


--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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