diff options
| -rw-r--r-- | Lib/test/test_os.py | 19 | ||||
| -rw-r--r-- | Misc/NEWS | 5 | ||||
| -rw-r--r-- | Modules/posixmodule.c | 19 |
3 files changed, 37 insertions, 6 deletions
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py index f559841..588df16 100644 --- a/Lib/test/test_os.py +++ b/Lib/test/test_os.py @@ -43,6 +43,10 @@ try: import _winapi except ImportError: _winapi = None +try: + from _testcapi import INT_MAX +except ImportError: + INT_MAX = 2 ** 31 - 1 from test.script_helper import assert_python_ok @@ -119,6 +123,21 @@ class FileTests(unittest.TestCase): self.assertEqual(type(s), bytes) self.assertEqual(s, b"spam") + def test_large_read(self): + with open(support.TESTFN, "wb") as fp: + fp.write(b'test') + self.addCleanup(support.unlink, support.TESTFN) + + # Issue #21932: Make sure that os.read() does not raise an + # OverflowError for size larger than INT_MAX + size = INT_MAX + 10 + with open(support.TESTFN, "rb") as fp: + data = os.read(fp.fileno(), size) + + # The test does not try to read more than 2 GB at once because the + # operating system is free to return less bytes than requested. + self.assertEqual(data, b'test') + def test_write(self): # os.write() accepts bytes- and buffer-like objects but not strings fd = os.open(support.TESTFN, os.O_CREAT | os.O_WRONLY) @@ -108,6 +108,11 @@ Core and Builtins Library ------- +- Issue #21932: os.read() now uses a :c:func:`Py_ssize_t` type instead of + :c:type:`int` for the size to support reading more than 2 GB at once. On + Windows, the size is truncted to INT_MAX. As any call to os.read(), the OS + may read less bytes than the number of requested bytes. + - Issue #21942: Fixed source file viewing in pydoc's server mode on Windows. - Issue #11259: asynchat.async_chat().set_terminator() now raises a ValueError diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c index 899618f..b7acbc3 100644 --- a/Modules/posixmodule.c +++ b/Modules/posixmodule.c @@ -7989,11 +7989,18 @@ Read a file descriptor."); static PyObject * posix_read(PyObject *self, PyObject *args) { - int fd, size; + int fd; + Py_ssize_t size; Py_ssize_t n; PyObject *buffer; - if (!PyArg_ParseTuple(args, "ii:read", &fd, &size)) + if (!PyArg_ParseTuple(args, "in:read", &fd, &size)) return NULL; + if (!_PyVerify_fd(fd)) + return posix_error(); +#ifdef MS_WINDOWS + if (size > INT_MAX) + size = INT_MAX; +#endif if (size < 0) { errno = EINVAL; return posix_error(); @@ -8001,12 +8008,12 @@ posix_read(PyObject *self, PyObject *args) buffer = PyBytes_FromStringAndSize((char *)NULL, size); if (buffer == NULL) return NULL; - if (!_PyVerify_fd(fd)) { - Py_DECREF(buffer); - return posix_error(); - } Py_BEGIN_ALLOW_THREADS +#ifdef MS_WINDOWS + n = read(fd, PyBytes_AS_STRING(buffer), (int)size); +#else n = read(fd, PyBytes_AS_STRING(buffer), size); +#endif Py_END_ALLOW_THREADS if (n < 0) { Py_DECREF(buffer); |