Enable the mmap module

from_cpython/CMakeLists.txt

@@ -125,6 +125,7 @@ add_custom_command(OUTPUT
                        ${CMAKE_BINARY_DIR}/lib_pyston/grp.pyston.so
                        ${CMAKE_BINARY_DIR}/lib_pyston/termios.pyston.so
                        ${CMAKE_BINARY_DIR}/lib_pyston/_curses.pyston.so
+                       ${CMAKE_BINARY_DIR}/lib_pyston/mmap.pyston.so
                    COMMAND ${CMAKE_BINARY_DIR}/pyston setup.py build --build-lib ${CMAKE_BINARY_DIR}/lib_pyston
                    DEPENDS
                        pyston
@@ -150,5 +151,6 @@ add_custom_command(OUTPUT
 		       Modules/grpmodule.c
 		       Modules/termios.c
 		       Modules/_cursesmodule.c
+		       Modules/mmapmodule.c
                    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
 add_custom_target(sharedmods DEPENDS ${CMAKE_BINARY_DIR}/lib_pyston/_multiprocessing.pyston.so)

from_cpython/Lib/test/test_mmap.py

+from test.test_support import (TESTFN, run_unittest, import_module, unlink,
+                               requires, _2G, _4G)
+import unittest
+import os, re, itertools, socket, sys
+
+mmap = import_module('mmap')
+
+PAGESIZE = mmap.PAGESIZE
+
+class MmapTests(unittest.TestCase):
+
+    def setUp(self):
+        if os.path.exists(TESTFN):
+            os.unlink(TESTFN)
+
+    def tearDown(self):
+        try:
+            os.unlink(TESTFN)
+        except OSError:
+            pass
+
+    def test_basic(self):
+        # Test mmap module on Unix systems and Windows
+
+        # Create a file to be mmap'ed.
+        f = open(TESTFN, 'w+')
+        try:
+            # Write 2 pages worth of data to the file
+            f.write('\0'* PAGESIZE)
+            f.write('foo')
+            f.write('\0'* (PAGESIZE-3) )
+            f.flush()
+            m = mmap.mmap(f.fileno(), 2 * PAGESIZE)
+            f.close()
+
+            # Simple sanity checks
+
+            tp = str(type(m))  # SF bug 128713:  segfaulted on Linux
+            self.assertEqual(m.find('foo'), PAGESIZE)
+
+            self.assertEqual(len(m), 2*PAGESIZE)
+
+            self.assertEqual(m[0], '\0')
+            self.assertEqual(m[0:3], '\0\0\0')
+
+            # Shouldn't crash on boundary (Issue #5292)
+            self.assertRaises(IndexError, m.__getitem__, len(m))
+            self.assertRaises(IndexError, m.__setitem__, len(m), '\0')
+
+            # Modify the file's content
+            m[0] = '3'
+            m[PAGESIZE +3: PAGESIZE +3+3] = 'bar'
+
+            # Check that the modification worked
+            self.assertEqual(m[0], '3')
+            self.assertEqual(m[0:3], '3\0\0')
+            self.assertEqual(m[PAGESIZE-1 : PAGESIZE + 7], '\0foobar\0')
+
+            m.flush()
+
+            # Test doing a regular expression match in an mmap'ed file
+            match = re.search('[A-Za-z]+', m)
+            if match is None:
+                self.fail('regex match on mmap failed!')
+            else:
+                start, end = match.span(0)
+                length = end - start
+
+                self.assertEqual(start, PAGESIZE)
+                self.assertEqual(end, PAGESIZE + 6)
+
+            # test seeking around (try to overflow the seek implementation)
+            m.seek(0,0)
+            self.assertEqual(m.tell(), 0)
+            m.seek(42,1)
+            self.assertEqual(m.tell(), 42)
+            m.seek(0,2)
+            self.assertEqual(m.tell(), len(m))
+
+            # Try to seek to negative position...
+            self.assertRaises(ValueError, m.seek, -1)
+
+            # Try to seek beyond end of mmap...
+            self.assertRaises(ValueError, m.seek, 1, 2)
+
+            # Try to seek to negative position...
+            self.assertRaises(ValueError, m.seek, -len(m)-1, 2)
+
+            # Try resizing map
+            try:
+                m.resize(512)
+            except SystemError:
+                # resize() not supported
+                # No messages are printed, since the output of this test suite
+                # would then be different across platforms.
+                pass
+            else:
+                # resize() is supported
+                self.assertEqual(len(m), 512)
+                # Check that we can no longer seek beyond the new size.
+                self.assertRaises(ValueError, m.seek, 513, 0)
+
+                # Check that the underlying file is truncated too
+                # (bug #728515)
+                f = open(TESTFN)
+                f.seek(0, 2)
+                self.assertEqual(f.tell(), 512)
+                f.close()
+                self.assertEqual(m.size(), 512)
+
+            m.close()
+
+        finally:
+            try:
+                f.close()
+            except OSError:
+                pass
+
+    def test_access_parameter(self):
+        # Test for "access" keyword parameter
+        mapsize = 10
+        open(TESTFN, "wb").write("a"*mapsize)
+        f = open(TESTFN, "rb")
+        m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_READ)
+        self.assertEqual(m[:], 'a'*mapsize, "Readonly memory map data incorrect.")
+
+        # Ensuring that readonly mmap can't be slice assigned
+        try:
+            m[:] = 'b'*mapsize
+        except TypeError:
+            pass
+        else:
+            self.fail("Able to write to readonly memory map")
+
+        # Ensuring that readonly mmap can't be item assigned
+        try:
+            m[0] = 'b'
+        except TypeError:
+            pass
+        else:
+            self.fail("Able to write to readonly memory map")
+
+        # Ensuring that readonly mmap can't be write() to
+        try:
+            m.seek(0,0)
+            m.write('abc')
+        except TypeError:
+            pass
+        else:
+            self.fail("Able to write to readonly memory map")
+
+        # Ensuring that readonly mmap can't be write_byte() to
+        try:
+            m.seek(0,0)
+            m.write_byte('d')
+        except TypeError:
+            pass
+        else:
+            self.fail("Able to write to readonly memory map")
+
+        # Ensuring that readonly mmap can't be resized
+        try:
+            m.resize(2*mapsize)
+        except SystemError:   # resize is not universally supported
+            pass
+        except TypeError:
+            pass
+        else:
+            self.fail("Able to resize readonly memory map")
+        f.close()
+        del m, f
+        self.assertEqual(open(TESTFN, "rb").read(), 'a'*mapsize,
+               "Readonly memory map data file was modified")
+
+        # Opening mmap with size too big
+        import sys
+        f = open(TESTFN, "r+b")
+        try:
+            m = mmap.mmap(f.fileno(), mapsize+1)
+        except ValueError:
+            # we do not expect a ValueError on Windows
+            # CAUTION:  This also changes the size of the file on disk, and
+            # later tests assume that the length hasn't changed.  We need to
+            # repair that.
+            if sys.platform.startswith('win'):
+                self.fail("Opening mmap with size+1 should work on Windows.")
+        else:
+            # we expect a ValueError on Unix, but not on Windows
+            if not sys.platform.startswith('win'):
+                self.fail("Opening mmap with size+1 should raise ValueError.")
+            m.close()
+        f.close()
+        if sys.platform.startswith('win'):
+            # Repair damage from the resizing test.
+            f = open(TESTFN, 'r+b')
+            f.truncate(mapsize)
+            f.close()
+
+        # Opening mmap with access=ACCESS_WRITE
+        f = open(TESTFN, "r+b")
+        m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_WRITE)
+        # Modifying write-through memory map
+        m[:] = 'c'*mapsize
+        self.assertEqual(m[:], 'c'*mapsize,
+               "Write-through memory map memory not updated properly.")
+        m.flush()
+        m.close()
+        f.close()
+        f = open(TESTFN, 'rb')
+        stuff = f.read()
+        f.close()
+        self.assertEqual(stuff, 'c'*mapsize,
+               "Write-through memory map data file not updated properly.")
+
+        # Opening mmap with access=ACCESS_COPY
+        f = open(TESTFN, "r+b")
+        m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_COPY)
+        # Modifying copy-on-write memory map
+        m[:] = 'd'*mapsize
+        self.assertEqual(m[:], 'd' * mapsize,
+               "Copy-on-write memory map data not written correctly.")
+        m.flush()
+        self.assertEqual(open(TESTFN, "rb").read(), 'c'*mapsize,
+               "Copy-on-write test data file should not be modified.")
+        # Ensuring copy-on-write maps cannot be resized
+        self.assertRaises(TypeError, m.resize, 2*mapsize)
+        f.close()
+        del m, f
+
+        # Ensuring invalid access parameter raises exception
+        f = open(TESTFN, "r+b")
+        self.assertRaises(ValueError, mmap.mmap, f.fileno(), mapsize, access=4)
+        f.close()
+
+        if os.name == "posix":
+            # Try incompatible flags, prot and access parameters.
+            f = open(TESTFN, "r+b")
+            self.assertRaises(ValueError, mmap.mmap, f.fileno(), mapsize,
+                              flags=mmap.MAP_PRIVATE,
+                              prot=mmap.PROT_READ, access=mmap.ACCESS_WRITE)
+            f.close()
+
+            # Try writing with PROT_EXEC and without PROT_WRITE
+            prot = mmap.PROT_READ | getattr(mmap, 'PROT_EXEC', 0)
+            with open(TESTFN, "r+b") as f:
+                m = mmap.mmap(f.fileno(), mapsize, prot=prot)
+                self.assertRaises(TypeError, m.write, b"abcdef")
+                self.assertRaises(TypeError, m.write_byte, 0)
+                m.close()
+
+    def test_bad_file_desc(self):
+        # Try opening a bad file descriptor...
+        self.assertRaises(mmap.error, mmap.mmap, -2, 4096)
+
+    def test_tougher_find(self):
+        # Do a tougher .find() test.  SF bug 515943 pointed out that, in 2.2,
+        # searching for data with embedded \0 bytes didn't work.
+        f = open(TESTFN, 'w+')
+
+        data = 'aabaac\x00deef\x00\x00aa\x00'
+        n = len(data)
+        f.write(data)
+        f.flush()
+        m = mmap.mmap(f.fileno(), n)
+        f.close()
+
+        for start in range(n+1):
+            for finish in range(start, n+1):
+                slice = data[start : finish]
+                self.assertEqual(m.find(slice), data.find(slice))
+                self.assertEqual(m.find(slice + 'x'), -1)
+        m.close()
+
+    def test_find_end(self):
+        # test the new 'end' parameter works as expected
+        f = open(TESTFN, 'w+')
+        data = 'one two ones'
+        n = len(data)
+        f.write(data)
+        f.flush()
+        m = mmap.mmap(f.fileno(), n)
+        f.close()
+
+        self.assertEqual(m.find('one'), 0)
+        self.assertEqual(m.find('ones'), 8)
+        self.assertEqual(m.find('one', 0, -1), 0)
+        self.assertEqual(m.find('one', 1), 8)
+        self.assertEqual(m.find('one', 1, -1), 8)
+        self.assertEqual(m.find('one', 1, -2), -1)
+
+
+    def test_rfind(self):
+        # test the new 'end' parameter works as expected
+        f = open(TESTFN, 'w+')
+        data = 'one two ones'
+        n = len(data)
+        f.write(data)
+        f.flush()
+        m = mmap.mmap(f.fileno(), n)
+        f.close()
+
+        self.assertEqual(m.rfind('one'), 8)
+        self.assertEqual(m.rfind('one '), 0)
+        self.assertEqual(m.rfind('one', 0, -1), 8)
+        self.assertEqual(m.rfind('one', 0, -2), 0)
+        self.assertEqual(m.rfind('one', 1, -1), 8)
+        self.assertEqual(m.rfind('one', 1, -2), -1)
+
+
+    def test_double_close(self):
+        # make sure a double close doesn't crash on Solaris (Bug# 665913)
+        f = open(TESTFN, 'w+')
+
+        f.write(2**16 * 'a') # Arbitrary character
+        f.close()
+
+        f = open(TESTFN)
+        mf = mmap.mmap(f.fileno(), 2**16, access=mmap.ACCESS_READ)
+        mf.close()
+        mf.close()
+        f.close()
+
+    @unittest.skipUnless(hasattr(os, "stat"), "needs os.stat()")
+    def test_entire_file(self):
+        # test mapping of entire file by passing 0 for map length
+        f = open(TESTFN, "w+")
+
+        f.write(2**16 * 'm') # Arbitrary character
+        f.close()
+
+        f = open(TESTFN, "rb+")
+        mf = mmap.mmap(f.fileno(), 0)
+        self.assertEqual(len(mf), 2**16, "Map size should equal file size.")
+        self.assertEqual(mf.read(2**16), 2**16 * "m")
+        mf.close()
+        f.close()
+
+    @unittest.skipUnless(hasattr(os, "stat"), "needs os.stat()")
+    def test_length_0_offset(self):
+        # Issue #10916: test mapping of remainder of file by passing 0 for
+        # map length with an offset doesn't cause a segfault.
+        # NOTE: allocation granularity is currently 65536 under Win64,
+        # and therefore the minimum offset alignment.
+        with open(TESTFN, "wb") as f:
+            f.write((65536 * 2) * b'm') # Arbitrary character
+
+        with open(TESTFN, "rb") as f:
+            mf = mmap.mmap(f.fileno(), 0, offset=65536, access=mmap.ACCESS_READ)
+            try:
+                self.assertRaises(IndexError, mf.__getitem__, 80000)
+            finally:
+                mf.close()
+
+    @unittest.skipUnless(hasattr(os, "stat"), "needs os.stat()")
+    def test_length_0_large_offset(self):
+        # Issue #10959: test mapping of a file by passing 0 for
+        # map length with a large offset doesn't cause a segfault.
+        with open(TESTFN, "wb") as f:
+            f.write(115699 * b'm') # Arbitrary character
+
+        with open(TESTFN, "w+b") as f:
+            self.assertRaises(ValueError, mmap.mmap, f.fileno(), 0,
+                              offset=2147418112)
+
+    def test_move(self):
+        # make move works everywhere (64-bit format problem earlier)
+        f = open(TESTFN, 'w+')
+
+        f.write("ABCDEabcde") # Arbitrary character
+        f.flush()
+
+        mf = mmap.mmap(f.fileno(), 10)
+        mf.move(5, 0, 5)
+        self.assertEqual(mf[:], "ABCDEABCDE", "Map move should have duplicated front 5")
+        mf.close()
+        f.close()
+
+        # more excessive test
+        data = "0123456789"
+        for dest in range(len(data)):
+            for src in range(len(data)):
+                for count in range(len(data) - max(dest, src)):
+                    expected = data[:dest] + data[src:src+count] + data[dest+count:]
+                    m = mmap.mmap(-1, len(data))
+                    m[:] = data
+                    m.move(dest, src, count)
+                    self.assertEqual(m[:], expected)
+                    m.close()
+
+        # segfault test (Issue 5387)
+        m = mmap.mmap(-1, 100)
+        offsets = [-100, -1, 0, 1, 100]
+        for source, dest, size in itertools.product(offsets, offsets, offsets):
+            try:
+                m.move(source, dest, size)
+            except ValueError:
+                pass
+
+        offsets = [(-1, -1, -1), (-1, -1, 0), (-1, 0, -1), (0, -1, -1),
+                   (-1, 0, 0), (0, -1, 0), (0, 0, -1)]
+        for source, dest, size in offsets:
+            self.assertRaises(ValueError, m.move, source, dest, size)
+
+        m.close()
+
+        m = mmap.mmap(-1, 1) # single byte
+        self.assertRaises(ValueError, m.move, 0, 0, 2)
+        self.assertRaises(ValueError, m.move, 1, 0, 1)
+        self.assertRaises(ValueError, m.move, 0, 1, 1)
+        m.move(0, 0, 1)
+        m.move(0, 0, 0)
+
+
+    def test_anonymous(self):
+        # anonymous mmap.mmap(-1, PAGE)
+        m = mmap.mmap(-1, PAGESIZE)
+        for x in xrange(PAGESIZE):
+            self.assertEqual(m[x], '\0', "anonymously mmap'ed contents should be zero")
+
+        for x in xrange(PAGESIZE):
+            m[x] = ch = chr(x & 255)
+            self.assertEqual(m[x], ch)
+
+    def test_extended_getslice(self):
+        # Test extended slicing by comparing with list slicing.
+        s = "".join(chr(c) for c in reversed(range(256)))
+        m = mmap.mmap(-1, len(s))
+        m[:] = s
+        self.assertEqual(m[:], s)
+        indices = (0, None, 1, 3, 19, 300, -1, -2, -31, -300)
+        for start in indices:
+            for stop in indices:
+                # Skip step 0 (invalid)
+                for step in indices[1:]:
+                    self.assertEqual(m[start:stop:step],
+                                     s[start:stop:step])
+
+    def test_extended_set_del_slice(self):
+        # Test extended slicing by comparing with list slicing.
+        s = "".join(chr(c) for c in reversed(range(256)))
+        m = mmap.mmap(-1, len(s))
+        indices = (0, None, 1, 3, 19, 300, -1, -2, -31, -300)
+        for start in indices:
+            for stop in indices:
+                # Skip invalid step 0
+                for step in indices[1:]:
+                    m[:] = s
+                    self.assertEqual(m[:], s)
+                    L = list(s)
+                    # Make sure we have a slice of exactly the right length,
+                    # but with different data.
+                    data = L[start:stop:step]
+                    data = "".join(reversed(data))
+                    L[start:stop:step] = data
+                    m[start:stop:step] = data
+                    self.assertEqual(m[:], "".join(L))
+
+    def make_mmap_file (self, f, halfsize):
+        # Write 2 pages worth of data to the file
+        f.write ('\0' * halfsize)
+        f.write ('foo')
+        f.write ('\0' * (halfsize - 3))
+        f.flush ()
+        return mmap.mmap (f.fileno(), 0)
+
+    def test_empty_file (self):
+        f = open (TESTFN, 'w+b')
+        f.close()
+        with open(TESTFN, "rb") as f :
+            self.assertRaisesRegexp(ValueError,
+                                   "cannot mmap an empty file",
+                                   mmap.mmap, f.fileno(), 0,
+                                   access=mmap.ACCESS_READ)
+
+    def test_offset (self):
+        f = open (TESTFN, 'w+b')
+
+        try: # unlink TESTFN no matter what
+            halfsize = mmap.ALLOCATIONGRANULARITY
+            m = self.make_mmap_file (f, halfsize)
+            m.close ()
+            f.close ()
+
+            mapsize = halfsize * 2
+            # Try invalid offset
+            f = open(TESTFN, "r+b")
+            for offset in [-2, -1, None]:
+                try:
+                    m = mmap.mmap(f.fileno(), mapsize, offset=offset)
+                    self.assertEqual(0, 1)
+                except (ValueError, TypeError, OverflowError):
+                    pass
+                else:
+                    self.assertEqual(0, 0)
+            f.close()
+
+            # Try valid offset, hopefully 8192 works on all OSes
+            f = open(TESTFN, "r+b")
+            m = mmap.mmap(f.fileno(), mapsize - halfsize, offset=halfsize)
+            self.assertEqual(m[0:3], 'foo')
+            f.close()
+
+            # Try resizing map
+            try:
+                m.resize(512)
+            except SystemError:
+                pass
+            else:
+                # resize() is supported
+                self.assertEqual(len(m), 512)
+                # Check that we can no longer seek beyond the new size.
+                self.assertRaises(ValueError, m.seek, 513, 0)
+                # Check that the content is not changed
+                self.assertEqual(m[0:3], 'foo')
+
+                # Check that the underlying file is truncated too
+                f = open(TESTFN)
+                f.seek(0, 2)
+                self.assertEqual(f.tell(), halfsize + 512)
+                f.close()
+                self.assertEqual(m.size(), halfsize + 512)
+
+            m.close()
+
+        finally:
+            f.close()
+            try:
+                os.unlink(TESTFN)
+            except OSError:
+                pass
+
+    def test_subclass(self):
+        class anon_mmap(mmap.mmap):
+            def __new__(klass, *args, **kwargs):
+                return mmap.mmap.__new__(klass, -1, *args, **kwargs)
+        anon_mmap(PAGESIZE)
+
+    @unittest.skipUnless(hasattr(mmap, 'PROT_READ'), "needs mmap.PROT_READ")
+    def test_prot_readonly(self):
+        mapsize = 10
+        open(TESTFN, "wb").write("a"*mapsize)
+        f = open(TESTFN, "rb")
+        m = mmap.mmap(f.fileno(), mapsize, prot=mmap.PROT_READ)
+        self.assertRaises(TypeError, m.write, "foo")
+        f.close()
+
+    def test_error(self):
+        self.assertTrue(issubclass(mmap.error, EnvironmentError))
+        self.assertIn("mmap.error", str(mmap.error))
+
+    def test_io_methods(self):
+        data = "0123456789"
+        open(TESTFN, "wb").write("x"*len(data))
+        f = open(TESTFN, "r+b")
+        m = mmap.mmap(f.fileno(), len(data))
+        f.close()
+        # Test write_byte()
+        for i in xrange(len(data)):
+            self.assertEqual(m.tell(), i)
+            m.write_byte(data[i])
+            self.assertEqual(m.tell(), i+1)
+        self.assertRaises(ValueError, m.write_byte, "x")
+        self.assertEqual(m[:], data)
+        # Test read_byte()
+        m.seek(0)
+        for i in xrange(len(data)):
+            self.assertEqual(m.tell(), i)
+            self.assertEqual(m.read_byte(), data[i])
+            self.assertEqual(m.tell(), i+1)
+        self.assertRaises(ValueError, m.read_byte)
+        # Test read()
+        m.seek(3)
+        self.assertEqual(m.read(3), "345")
+        self.assertEqual(m.tell(), 6)
+        # Test write()
+        m.seek(3)
+        m.write("bar")
+        self.assertEqual(m.tell(), 6)
+        self.assertEqual(m[:], "012bar6789")
+        m.seek(8)
+        self.assertRaises(ValueError, m.write, "bar")
+
+    @unittest.skipUnless(os.name == 'nt', 'requires Windows')
+    def test_tagname(self):
+        data1 = "0123456789"
+        data2 = "abcdefghij"
+        assert len(data1) == len(data2)
+
+        # Test same tag
+        m1 = mmap.mmap(-1, len(data1), tagname="foo")
+        m1[:] = data1
+        m2 = mmap.mmap(-1, len(data2), tagname="foo")
+        m2[:] = data2
+        self.assertEqual(m1[:], data2)
+        self.assertEqual(m2[:], data2)
+        m2.close()
+        m1.close()
+
+        # Test different tag
+        m1 = mmap.mmap(-1, len(data1), tagname="foo")
+        m1[:] = data1
+        m2 = mmap.mmap(-1, len(data2), tagname="boo")
+        m2[:] = data2
+        self.assertEqual(m1[:], data1)
+        self.assertEqual(m2[:], data2)
+        m2.close()
+        m1.close()
+
+    @unittest.skipUnless(os.name == 'nt', 'requires Windows')
+    def test_crasher_on_windows(self):
+        # Should not crash (Issue 1733986)
+        m = mmap.mmap(-1, 1000, tagname="foo")
+        try:
+            mmap.mmap(-1, 5000, tagname="foo")[:] # same tagname, but larger size
+        except:
+            pass
+        m.close()
+
+        # Should not crash (Issue 5385)
+        open(TESTFN, "wb").write("x"*10)
+        f = open(TESTFN, "r+b")
+        m = mmap.mmap(f.fileno(), 0)
+        f.close()
+        try:
+            m.resize(0) # will raise WindowsError
+        except:
+            pass
+        try:
+            m[:]
+        except:
+            pass
+        m.close()
+
+    @unittest.skipUnless(os.name == 'nt', 'requires Windows')
+    def test_invalid_descriptor(self):
+        # socket file descriptors are valid, but out of range
+        # for _get_osfhandle, causing a crash when validating the
+        # parameters to _get_osfhandle.
+        s = socket.socket()
+        try:
+            with self.assertRaises(mmap.error):
+                m = mmap.mmap(s.fileno(), 10)
+        finally:
+            s.close()
+
+
+class LargeMmapTests(unittest.TestCase):
+
+    def setUp(self):
+        unlink(TESTFN)
+
+    def tearDown(self):
+        unlink(TESTFN)
+
+    def _make_test_file(self, num_zeroes, tail):
+        if sys.platform[:3] == 'win' or sys.platform == 'darwin':
+            requires('largefile',
+                'test requires %s bytes and a long time to run' % str(0x180000000))
+        f = open(TESTFN, 'w+b')
+        try:
+            f.seek(num_zeroes)
+            f.write(tail)
+            f.flush()
+        except (IOError, OverflowError):
+            f.close()
+            raise unittest.SkipTest("filesystem does not have largefile support")
+        return f
+
+    def test_large_offset(self):
+        with self._make_test_file(0x14FFFFFFF, b" ") as f:
+            m = mmap.mmap(f.fileno(), 0, offset=0x140000000, access=mmap.ACCESS_READ)
+            try:
+                self.assertEqual(m[0xFFFFFFF], b" ")
+            finally:
+                m.close()
+
+    def test_large_filesize(self):
+        with self._make_test_file(0x17FFFFFFF, b" ") as f:
+            if sys.maxsize < 0x180000000:
+                # On 32 bit platforms the file is larger than sys.maxsize so
+                # mapping the whole file should fail -- Issue #16743
+                with self.assertRaises(OverflowError):
+                    mmap.mmap(f.fileno(), 0x180000000, access=mmap.ACCESS_READ)
+                with self.assertRaises(ValueError):
+                    mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+            m = mmap.mmap(f.fileno(), 0x10000, access=mmap.ACCESS_READ)
+            try:
+                self.assertEqual(m.size(), 0x180000000)
+            finally:
+                m.close()
+
+    # Issue 11277: mmap() with large (~4GB) sparse files crashes on OS X.
+
+    def _test_around_boundary(self, boundary):
+        tail = b'  DEARdear  '
+        start = boundary - len(tail) // 2
+        end = start + len(tail)
+        with self._make_test_file(start, tail) as f:
+            m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+            try:
+                self.assertEqual(m[start:end], tail)
+            finally:
+                m.close()
+
+    @unittest.skipUnless(sys.maxsize > _4G, "test cannot run on 32-bit systems")
+    def test_around_2GB(self):
+        self._test_around_boundary(_2G)
+
+    @unittest.skipUnless(sys.maxsize > _4G, "test cannot run on 32-bit systems")
+    def test_around_4GB(self):
+        self._test_around_boundary(_4G)
+
+
+def test_main():
+    run_unittest(MmapTests, LargeMmapTests)
+
+if __name__ == '__main__':
+    test_main()

from_cpython/setup.py

@@ -88,6 +88,12 @@ def termios_ext():
             "Modules/termios.c",
             ]))
 
+@unique
+def mmap_ext():
+    return Extension("mmap", sources = map(relpath, [
+            "Modules/mmapmodule.c",
+            ]))
+
 @unique
 def pyexpat_ext():
     define_macros = [('HAVE_EXPAT_CONFIG_H', '1'),]
@@ -136,7 +142,9 @@ ext_modules = [future_builtins_ext(),
                ctypes_test_ext(),
                grp_ext(),
                curses_ext(),
-               termios_ext()]
+               termios_ext(),
+               mmap_ext(),
+               ]
 
 builtin_headers = map(relpath, glob.glob("Include/*.h"))
 

test/cpython/test_mmap.py

+../../from_cpython/Lib/test/test_mmap.py
\ No newline at end of file