bpo-24658: Fix read/write greater than 2 GiB on macOS (GH-1705)
On macOS, fix reading from and writing into a file with a size larger than 2 GiB.
(cherry picked from commit 74a8b6ea7e0a8508b13a1c75ec9b91febd8b5557)
Co-authored-by: Stéphane Wirtel <stephane@wirtel.be>
diff --git a/Include/fileutils.h b/Include/fileutils.h
index e4bf6d4..c05ff43 100644
--- a/Include/fileutils.h
+++ b/Include/fileutils.h
@@ -60,6 +60,19 @@
#ifndef Py_LIMITED_API
PyAPI_FUNC(PyObject *) _Py_device_encoding(int);
+#if defined(MS_WINDOWS) || defined(__APPLE__)
+ /* On Windows, the count parameter of read() is an int (bpo-9015, bpo-9611).
+ On macOS 10.13, read() and write() with more than INT_MAX bytes
+ fail with EINVAL (bpo-24658). */
+# define _PY_READ_MAX INT_MAX
+# define _PY_WRITE_MAX INT_MAX
+#else
+ /* write() should truncate the input to PY_SSIZE_T_MAX bytes,
+ but it's safer to do it ourself to have a portable behaviour */
+# define _PY_READ_MAX PY_SSIZE_T_MAX
+# define _PY_WRITE_MAX PY_SSIZE_T_MAX
+#endif
+
#ifdef MS_WINDOWS
struct _Py_stat_struct {
unsigned long st_dev;