Is deallocating MACH_PORT_NULL an error ?

[Justus Winter]

Hello :)

I've been hunting port handling bugs, and came up with the patch that
will follow this mail.  You will note that we do not print warnings if
MACH_PORT_NULL or MACH_PORT_DEAD is supplied:

runsystem@nonmonolithic / > (mach-port-deallocate mach-task-self MACH_PORT_NULL)
Error: (mach-port-deallocate: (os/kern) invalid name)
runsystem@nonmonolithic / > (mach-port-deallocate mach-task-self MACH_PORT_DEAD)
Error: (mach-port-deallocate: (os/kern) invalid name)
runsystem@nonmonolithic / > (mach-port-deallocate mach-task-self 1337)
task bootshell deallocating an invalid port 1337, most probably a bug.
Error: (mach-port-deallocate: (os/kern) invalid name)

When I tried to also print warnings in these cases, I was overwhelmed
by them.  On the other hand I know that these are likely in the libc
(b/c of the process names I saw, and I have a coccinelle patch that
adds error handling to most of these calls in the Hurd sources [the
patch is too noisy to commit though]).

So do we consider {deallocating,destroying,mod_refing} MACH_PORT_NULL
or MACH_PORT_DEAD an error, or an expensive nop ?

Justus