kern_descrip.c: add fdshare()/fdcopy()

kern_fork.c: add the tiny bit of code for rfork operation.
kern/sysv_*: shmfork() takes one less arg, it was never used.
sys/shm.h: drop "isvfork" arg from shmfork() prototype
sys/param.h: declare rfork args.. (this is where OpenBSD put it..)
sys/filedesc.h: protos for fdshare/fdcopy.
vm/vm_mmap.c: add minherit code, add rounding to mmap() type args where
it makes sense.
vm/*: drop unused isvfork arg.

Note: this rfork() implementation copies the address space mappings,
it does not connect the mappings together.  ie: once the two processes
have split, the pages may be shared, but the address space is not. If one
does a mmap() etc, it does not appear in the other.  This makes it not
useful for pthreads, but it is useful in it's own right for having
light-weight threads in a static shared address space.

Obtained from: Original by Ron Minnich, extended by OpenBSD

1 files changed, 2 insertions, 3 deletions

diff --git a/sys/kern/sysv_shm.c b/sys/kern/sysv_shm.c
index 72c8a22..a68f8a6 100644
--- a/sys/kern/sysv_shm.c
+++ b/sys/kern/sysv_shm.c
@@ -1,4 +1,4 @@
-/*	$Id: sysv_shm.c,v 1.16 1995/12/26 16:03:32 joerg Exp $ */
+/*	$Id: sysv_shm.c,v 1.17 1996/01/05 16:38:03 wollman Exp $ */
 /*	$NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $	*/
 
 /*
@@ -565,9 +565,8 @@ shmsys(p, uap, retval)
 }
 
 void
-shmfork(p1, p2, isvfork)
+shmfork(p1, p2)
 	struct proc *p1, *p2;
-	int isvfork;
 {
 	struct shmmap_state *shmmap_s;
 	size_t size;