#15676: mmap: add empty file check prior to offset check <- Previous patch was incomplete
diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py
index 31b3695..0701b96 100644
--- a/Lib/test/test_mmap.py
+++ b/Lib/test/test_mmap.py
@@ -469,18 +469,15 @@
def test_empty_file (self):
f = open (TESTFN, 'w+b')
f.close()
- f = open(TESTFN, "rb")
- try:
- m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
- m.close()
- f.close()
- self.fail("should not have been able to mmap empty file")
- except ValueError as e:
- f.close()
- self.assertEqual(e.message, "cannot mmap an empty file")
- except:
- f.close()
- self.fail("unexpected exception: " + str(e))
+ with open(TESTFN, "rb") as f :
+ try:
+ m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+ m.close()
+ self.fail("should not have been able to mmap empty file")
+ except ValueError as e:
+ self.assertEqual(e.message, "cannot mmap an empty file")
+ except:
+ self.fail("unexpected exception: " + str(e))
def test_offset (self):
f = open (TESTFN, 'w+b')
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 8cf0e87..62d934c 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -1388,6 +1388,11 @@
}
size = (((PY_LONG_LONG) high) << 32) + low;
+ if (size == 0) {
+ PyErr_SetString(PyExc_ValueError,
+ "cannot mmap an empty file");
+ return NULL;
+ }
if (offset >= size) {
PyErr_SetString(PyExc_ValueError,
"mmap offset is greater than file size");