bpo-38110: Use fdwalk for os.closerange() when available. (GH-15224)

Use fdwalk() on platforms that support it to implement os.closerange().
(cherry picked from commit e20134f889a0cfcc37a46979f31a1c98b800de07)

Co-authored-by: Jakub Kulík <Kulikjak@gmail.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index cf6c00b..a066eb1 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -8419,6 +8419,21 @@ os_close_impl(PyObject *module, int fd)
 }
 
 
+#ifdef HAVE_FDWALK
+static int
+_fdwalk_close_func(void *lohi, int fd)
+{
+    int lo = ((int *)lohi)[0];
+    int hi = ((int *)lohi)[1];
+
+    if (fd >= hi)
+        return 1;
+    else if (fd >= lo)
+        close(fd);
+    return 0;
+}
+#endif /* HAVE_FDWALK */
+
 /*[clinic input]
 os.closerange
 
@@ -8433,11 +8448,21 @@ static PyObject *
 os_closerange_impl(PyObject *module, int fd_low, int fd_high)
 /*[clinic end generated code: output=0ce5c20fcda681c2 input=5855a3d053ebd4ec]*/
 {
+#ifdef HAVE_FDWALK
+    int lohi[2];
+#else
     int i;
+#endif
     Py_BEGIN_ALLOW_THREADS
     _Py_BEGIN_SUPPRESS_IPH
+#ifdef HAVE_FDWALK
+    lohi[0] = Py_MAX(fd_low, 0);
+    lohi[1] = fd_high;
+    fdwalk(_fdwalk_close_func, lohi);
+#else
     for (i = Py_MAX(fd_low, 0); i < fd_high; i++)
         close(i);
+#endif
     _Py_END_SUPPRESS_IPH
     Py_END_ALLOW_THREADS
     Py_RETURN_NONE;