kern/50480: posix_spawn vs. fork code duplication

[dholland%netbsd.org@localhost]

>Number:         50480
>Category:       kern
>Synopsis:       posix_spawn vs. fork code duplication
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Nov 26 23:15:00 +0000 2015
>Originator:     David A. Holland
>Release:        NetBSD 7.99.21 (20151118)
>Organization:
>Environment:
System: NetBSD valkyrie 7.99.1 NetBSD 7.99.1 (VALKYRIE) #17: Wed Oct 14 03:21:03 EDT 2015  dholland@valkyrie:/usr/src/sys/arch/amd64/compile/VALKYRIE amd64
Architecture: x86_64
Machine: amd64
>Description:

Most of the process-copying logic in fork is cutpasted into
posix_spawn. Except the posix_spawn copy isn't the same because
posix_spawn doesn't support (or have any reason to support) clone().

This is an obvious long-term hazard.

>How-To-Repeat:

code reading

>Fix:
one of those fun source reorgs