svn commit: r213886 - stable/8/sys/vm

[Alan Cox]

Author: alc
Date: Fri Oct 15 02:58:49 2010
New Revision: 213886
URL: http://svn.freebsd.org/changeset/base/213886

Log:
  MFC r212873
    Allow a POSIX shared memory object that is opened for read but not for
    write to nonetheless be mapped PROT_WRITE and MAP_PRIVATE, i.e.,
    copy-on-write.
  
  PR:		150260

Modified:
  stable/8/sys/vm/vm_mmap.c
Directory Properties:
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)

Modified: stable/8/sys/vm/vm_mmap.c
==============================================================================
--- stable/8/sys/vm/vm_mmap.c	Thu Oct 14 23:38:37 2010	(r213885)
+++ stable/8/sys/vm/vm_mmap.c	Fri Oct 15 02:58:49 2010	(r213886)
@@ -1316,7 +1316,8 @@ vm_mmap_shm(struct thread *td, vm_size_t
 {
 	int error;
 
-	if ((*maxprotp & VM_PROT_WRITE) == 0 &&
+	if ((*flagsp & MAP_SHARED) != 0 &&
+	    (*maxprotp & VM_PROT_WRITE) == 0 &&
 	    (prot & PROT_WRITE) != 0)
 		return (EACCES);
 #ifdef MAC