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

On 2019-05-16, Christian Brauner christian@brauner.io 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@brauner.io 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.