From ee31675efc06d1df6806cfcdfc4102271e596c96 Mon Sep 17 00:00:00 2001
From: "Anthony G. Basile" <blueness@gentoo.org>
Date: Fri, 27 May 2016 09:47:34 -0400
Subject: [PATCH 3/3] pym/portage/util/locale.py: add a C module to help check
 locale

The current method to check for a sane system locale is to use python's
ctypes.util.find_library() to construct a full library path to the
system libc.so and pass that path to ctypes.CDLL() so we can call
toupper() and tolower() directly.  However, this gets bogged down in
implementation details and fails with musl.

We work around this design flaw in ctypes with a small python module
written in C which provides thin wrappers to toupper() and tolower(),
and only fall back on the current ctypes-based check when this module
is not available.

This has been tested on glibc, uClibc and musl systems.

X-Gentoo-bug: 571444
X-Gentoo-bug-url: https://bugs.gentoo.org/show_bug.cgi?id=571444

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
---
 pym/portage/util/locale.py | 16 ++++++-----
 setup.py                   |  6 +++-
 src/portage_util_libc.c    | 68 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 8 deletions(-)
 create mode 100644 src/portage_util_libc.c

diff --git a/pym/portage/util/locale.py b/pym/portage/util/locale.py
index 093eb86..5b09945 100644
--- a/pym/portage/util/locale.py
+++ b/pym/portage/util/locale.py
@@ -34,13 +34,15 @@ def _check_locale(silent):
 	"""
 	The inner locale check function.
 	"""
-
-	libc_fn = find_library("c")
-	if libc_fn is None:
-		return None
-	libc = LoadLibrary(libc_fn)
-	if libc is None:
-		return None
+	try:
+		from portage.util import libc
+	except ImportError:
+		libc_fn = find_library("c")
+		if libc_fn is None:
+			return None
+		libc = LoadLibrary(libc_fn)
+		if libc is None:
+			return None
 
 	lc = list(range(ord('a'), ord('z')+1))
 	uc = list(range(ord('A'), ord('Z')+1))
diff --git a/setup.py b/setup.py
index 8d20355..d37ab29 100755
--- a/setup.py
+++ b/setup.py
@@ -47,7 +47,11 @@ x_scripts = {
 # Dictionary custom modules written in C/C++ here.  The structure is
 #   key   = module name
 #   value = list of C/C++ source code, path relative to top source directory
-x_c_helpers = {}
+x_c_helpers = {
+	'portage.util.libc' : [
+		'src/portage_util_libc.c',
+	],
+}
 
 class x_build(build):
 	""" Build command with extra build_man call. """
diff --git a/src/portage_util_libc.c b/src/portage_util_libc.c
new file mode 100644
index 0000000..977b954
--- /dev/null
+++ b/src/portage_util_libc.c
@@ -0,0 +1,68 @@
+/* Copyright 2005-2016 Gentoo Foundation
+ * Distributed under the terms of the GNU General Public License v2
+ */
+
+#include <Python.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+static PyObject * _libc_tolower(PyObject *, PyObject *);
+static PyObject * _libc_toupper(PyObject *, PyObject *);
+
+static PyMethodDef LibcMethods[] = {
+	{"tolower", _libc_tolower, METH_VARARGS, "Convert to lower case using system locale."},
+	{"toupper", _libc_toupper, METH_VARARGS, "Convert to upper case using system locale."},
+	{NULL, NULL, 0, NULL}
+};
+
+#if PY_MAJOR_VERSION >= 3
+static struct PyModuleDef moduledef = {
+	PyModuleDef_HEAD_INIT,
+	"libc",								/* m_name */
+	"Module for converting case using the system locale",		/* m_doc */
+	-1,								/* m_size */
+	LibcMethods,							/* m_methods */
+	NULL,								/* m_reload */
+	NULL,								/* m_traverse */
+	NULL,								/* m_clear */
+	NULL,								/* m_free */
+};
+
+PyMODINIT_FUNC
+PyInit_libc(void)
+{
+	PyObject *m;
+	m = PyModule_Create(&moduledef);
+	return m;
+}
+#else
+PyMODINIT_FUNC
+initlibc(void)
+{
+	Py_InitModule("libc", LibcMethods);
+}
+#endif
+
+
+static PyObject *
+_libc_tolower(PyObject *self, PyObject *args)
+{
+	int c;
+
+	if (!PyArg_ParseTuple(args, "i", &c))
+		return NULL;
+
+	return Py_BuildValue("i", tolower(c));
+}
+
+
+static PyObject *
+_libc_toupper(PyObject *self, PyObject *args)
+{
+	int c;
+
+	if (!PyArg_ParseTuple(args, "i", &c))
+		return NULL;
+
+	return Py_BuildValue("i", toupper(c));
+}
-- 
2.7.3