Re: mach_host_self() doesn't acquire new port name?!

[Thomas Bushnell, BSG]

Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de> writes:

> Overflowing the ip_srights reference count in the port structure.

Right.  So since mach_host_self sets OVERFLOW, the result of maxing
out the user refs is harmless.  (If it didn't set it, then
mach_host_self might sometimes get an error; that would be a problem,
but it does set it, so it isn't.)

That is, the kernel is doing Just The Right Thing.

For Hurd ports, the custom is that the port stays alive just until all
the send rights go away.  But that's not a generic rule: it's a Hurd
rule, and it doesn't necessarily apply to other ports besides the ones
using the standard Hurd interfaces.

Importantly, it does not apply to the host port.  The host port will
stay around always and forever, no matter how many or how few there
references there are, and there is no such thing as a "port leak" of
references to the host port, because the host port protocol does not
expect its users to keep track of the references.