commit 18f3327d9a99163a658697465eb00c31f86535eb
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Thu Nov 22 06:17:34 2018 -0800
committer GitHub <noreply@github.com> Thu Nov 22 06:17:34 2018 -0800
tree 31580d810447f0da0c5c8039c4f5f00c28f79e96
parent df6374e15aadff7eb547fc210c0f4f28bbff7010

bpo-24658: os.read() reuses _PY_READ_MAX (GH-10657)


os_read_impl() now also truncates the size to _PY_READ_MAX
on macOS, to avoid to allocate a larger buffer even if _Py_read() is
limited to _PY_READ_MAX bytes (ex: INT_MAX on macOS).
(cherry picked from commit 9a0d7a7648547ffb77144bf2480155f6d7940dea)

Co-authored-by: Victor Stinner <vstinner@redhat.com>

Modules/posixmodule.c

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 8ff487d..dbd534c 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -8021,11 +8021,7 @@
         return posix_error();
     }
 
-#ifdef MS_WINDOWS
-    /* On Windows, the count parameter of read() is an int */
-    if (length > INT_MAX)
-        length = INT_MAX;
-#endif
+    length = Py_MIN(length, _PY_READ_MAX);
 
     buffer = PyBytes_FromStringAndSize((char *)NULL, length);
     if (buffer == NULL)