[Python-checkins] cpython (3.2): Closes #15676: mmap: add empty file check prior to offset check

Mon Sep 10 01:24:45 CEST 2012

http://hg.python.org/cpython/rev/d85f80b31b54
changeset: 78929:d85f80b31b54
branch: 3.2
parent: 78927:b05547e8ff92
user: Jesus Cea <jcea at jcea.es>
date: Mon Sep 10 00:27:55 2012 +0200
summary:
 Closes #15676: mmap: add empty file check prior to offset check
files:
 Lib/test/test_mmap.py | 9 +++++++++
 Misc/NEWS | 3 +++
 Modules/mmapmodule.c | 5 +++++
 3 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py
--- a/Lib/test/test_mmap.py
+++ b/Lib/test/test_mmap.py
@@ -459,6 +459,15 @@
 f.flush ()
 return mmap.mmap (f.fileno(), 0)
 
+ def test_empty_file (self):
+ f = open (TESTFN, 'w+b')
+ f.close()
+ f = open(TESTFN, "rb")
+ self.assertRaisesRegex(ValueError,
+ "cannot mmap an empty file",
+ mmap.mmap, f.fileno(), 0, access=mmap.ACCESS_READ)
+ f.close()
+
 def test_offset (self):
 f = open (TESTFN, 'w+b')
 
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -463,6 +463,9 @@
 Extension Modules
 -----------------
 
+- Issue #15676: Now "mmap" check for empty files before doing the
+ offset check. Patch by Steven Willis.
+
 - Issue #6493: An issue in ctypes on Windows that caused structure bitfields
 of type ctypes.c_uint32 and width 32 to incorrectly be set has been fixed.
 
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -1141,6 +1141,11 @@
 if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) {
 if (map_size == 0) {
 off_t calc_size;
+ if (st.st_size == 0) {
+ PyErr_SetString(PyExc_ValueError,
+ "cannot mmap an empty file");
+ return NULL;
+ }
 if (offset >= st.st_size) {
 PyErr_SetString(PyExc_ValueError,
 "mmap offset is greater than file size");
-- 
Repository URL: http://hg.python.org/cpython
