.

wcfs/client/client_test.py

@@ -192,17 +192,17 @@ def test_wcfs_client_down_efault():
     fh = wconn.open(zf._p_oid)
     defer(fh.close)
 
-    m1 = fh.mmap(1, 4)
-    defer(m1.unmap)
+    m1 = fh.mmap(1, 4);  defer(m1.unmap)
+    m2 = fh.mmap(3, 3);  defer(m2.unmap)
 
     tm1 = tMapping(t, m1)
+    tm2 = tMapping(t, m2)
+
     tm1.assertBlk(1, '',   {})
     tm1.assertBlk(2, 'c1', {})
-    tm1.assertBlk(3, 'd1', {})
-    tm1.assertBlk(4, '',   {})
-
-    with panics("not faulted"): tm1.assertBlkFaults(2)
-    with panics("not faulted"): tm1.assertBlkFaults(3)
+    tm1.assertBlk(3, 'd1', {});  tm2.assertBlk(3, 'd1', {})
+    tm1.assertBlk(4, '',   {});  tm2.assertBlk(4, '',   {})
+    pass;                        tm2.assertBlk(5, '',   {})
 
     # close fileh -> m1 must turn into efaulting memory
     fh.close()
@@ -210,3 +210,13 @@ def test_wcfs_client_down_efault():
     tm1.assertBlkFaults(2)
     tm1.assertBlkFaults(3)
     tm1.assertBlkFaults(4)
+
+
+# verify that read_mustfault works as expected.
+def test_read_mustfault():
+    mem = mm.map_zero_ro(mm.PAGE_SIZE)
+    with panics("not faulted"): read_mustfault(mem[:1])
+    mm.protect(mem, mm.PROT_NONE)
+    read_mustfault(mem[:1])
+    mm.protect(mem, mm.PROT_READ)
+    with panics("not faulted"): read_mustfault(mem[:1])

wcfs/internal/mm.pyx

@@ -54,6 +54,11 @@ cdef extern from "<sys/user.h>":
         PAGE_SIZE
 
 cpdef enum:
+    PROT_EXEC       = mman.PROT_EXEC
+    PROT_READ       = mman.PROT_READ
+    PROT_WRITE      = mman.PROT_WRITE
+    PROT_NONE       = mman.PROT_NONE
+
     MLOCK_ONFAULT   = mman.MLOCK_ONFAULT
     MCL_CURRENT     = mman.MCL_CURRENT
     MCL_FUTURE      = mman.MCL_FUTURE
@@ -204,6 +209,20 @@ def advise(const unsigned char[::1] mem not None, int advice):
     return
 
 
+# protect sets protectionon a region of memory.
+#
+# see mprotect(2) for details.
+def protect(const unsigned char[::1] mem not None, int prot):
+    cdef const void *addr = &mem[0]
+    cdef size_t      size = mem.shape[0]
+
+    cdef err = mman.mprotect(<void *>addr, size, prot)
+    if err:
+        PyErr_SetFromErrno(OSError)
+
+    return
+
+
 # sync asks the kernel to synchronize the file with a memory map.
 #
 # see msync(2) for details.