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.

(This is a regression in the new implementation of POSIX shared memory
objects that is used by HEAD and RELENG_8.  This bug does not exist in
RELENG_7's user-level, file-based implementation.)

PR:		150260
MFC after:	3 weeks

This commit is contained in:

Alan Cox

2010-09-19 19:42:04 +00:00

parent 8304adaac6

commit da0483096d

1 changed files with 2 additions and 1 deletions

									
										sys/vm/vm_mmap.c
									
		+2
		-1
	
												View File
												
				@@ -1373,7 +1373,8 @@ vm_mmap_shm(struct thread *td, vm_size_t objsize,

				{

					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