Fix python HBAC bindings for python <= 2.4

Several parts of the HBAC python bindings did not work with old Python
versions, such as the one shipped in RHEL5.

The changes include:
* a compatibility wrapper around python set object
* PyModule_AddIntMacro compat macro
* Py_ssize_t compat definition
* Do not use PyUnicode_FromFormat
* several function prototypes and structures used to have "char
  arguments where they have "const char *" in recent versions.
  This caused compilation warnings this patch mitigates by using
  the discard_const hack on python 2.4

2 files changed, 167 insertions, 0 deletions

diff --git a/src/util/sss_python.c b/src/util/sss_python.c
new file mode 100644
index 00000000..19717a55
--- /dev/null
+++ b/src/util/sss_python.c
@@ -0,0 +1,104 @@
+/*
+    Authors:
+        Jakub Hrozek <jhrozek@redhat.com>
+
+    Copyright (C) 2011 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "src/util/sss_python.h"
+#include "config.h"
+
+PyObject *
+sss_python_set_new(void)
+{
+#ifdef HAVE_PYSET_NEW
+    return PySet_New(NULL);
+#else
+    return PyObject_CallObject((PyObject *) &PySet_Type, NULL);
+#endif
+}
+
+int
+sss_python_set_add(PyObject *set, PyObject *key)
+{
+#ifdef HAVE_PYSET_ADD
+    return PySet_Add(set, key);
+#else
+    PyObject *pyret;
+    int ret;
+
+    pyret = PyObject_CallMethod(set, sss_py_const_p(char, "add"),
+                                sss_py_const_p(char, "O"), key);
+    ret = (pyret == NULL) ? -1 : 0;
+    Py_XDECREF(pyret);
+    return ret;
+#endif
+}
+
+bool
+sss_python_set_check(PyObject *set)
+{
+#if HAVE_DECL_PYSET_CHECK
+    return PySet_Check(set);
+#else
+    return PyObject_TypeCheck(set, &PySet_Type);
+#endif
+}
+
+PyObject *
+sss_python_unicode_from_string(const char *u)
+{
+#ifdef HAVE_PYUNICODE_FROMSTRING
+    return PyUnicode_FromString(u);
+#else
+    return PyUnicode_DecodeUTF8(u, strlen(u), NULL);
+#endif
+}
+
+PyObject *
+sss_exception_with_doc(char *name, char *doc, PyObject *base, PyObject *dict)
+{
+#ifdef HAVE_PYERR_NEWEXCEPTIONWITHDOC
+    return PyErr_NewExceptionWithDoc(name, doc, base, dict);
+#else
+    int result;
+    PyObject *ret = NULL;
+    PyObject *mydict = NULL; /* points to the dict only if we create it */
+    PyObject *docobj;
+
+    if (dict == NULL) {
+        dict = mydict = PyDict_New();
+        if (dict == NULL) {
+            return NULL;
+        }
+    }
+
+    if (doc != NULL) {
+        docobj = PyString_FromString(doc);
+        if (docobj == NULL)
+            goto failure;
+        result = PyDict_SetItemString(dict, "__doc__", docobj);
+        Py_DECREF(docobj);
+        if (result < 0)
+            goto failure;
+    }
+
+    ret = PyErr_NewException(name, base, dict);
+  failure:
+    Py_XDECREF(mydict);
+    return ret;
+#endif
+}
diff --git a/src/util/sss_python.h b/src/util/sss_python.h
new file mode 100644
index 00000000..135c2877
--- /dev/null
+++ b/src/util/sss_python.h
@@ -0,0 +1,63 @@
+#ifndef __SSS_PYTHON_H__
+#define __SSS_PYTHON_H__
+
+#include <Python.h>
+#include <stdbool.h>
+#include "util/util.h"
+
+#if PY_VERSION_HEX < 0x02050000
+#define sss_py_const_p(type, value) discard_const_p(type, (value))
+#else
+#define sss_py_const_p(type, value) (value)
+#endif
+
+/* Py_ssize_t compatibility for python < 2.5 as per
+ * http://www.python.org/dev/peps/pep-0353/ */
+#ifndef HAVE_PY_SSIZE_T
+typedef int Py_ssize_t;
+#endif
+
+#ifndef PY_SSIZE_T_MAX
+#define PY_SSIZE_T_MAX INT_MAX
+#endif
+
+#ifndef PY_SSIZE_T_MIN
+#define PY_SSIZE_T_MIN INT_MIN
+#endif
+
+/* Wrappers providing the subset of C API for python's set objects we use */
+PyObject *sss_python_set_new(void);
+int sss_python_set_add(PyObject *set, PyObject *key);
+bool sss_python_set_check(PyObject *set);
+
+/* Unicode compatibility */
+PyObject *sss_python_unicode_from_string(const char *u);
+
+/* Exceptions compatibility */
+PyObject *
+sss_exception_with_doc(char *name, char *doc, PyObject *base, PyObject *dict);
+
+/* PyModule_AddIntMacro() compatibility */
+#if !HAVE_DECL_PYMODULE_ADDINTMACRO
+#define PyModule_AddIntMacro(m, c) PyModule_AddIntConstant(m, sss_py_const_p(char, #c), c)
+#endif
+
+/* Convenience macros */
+#define TYPE_READY(module, type, name) do {         \
+    if (PyType_Ready(&type) < 0)                    \
+        return;                                     \
+    Py_INCREF(&type);                               \
+    PyModule_AddObject(module,                      \
+                       discard_const_p(char, name), \
+                       (PyObject *) &type);         \
+} while(0);                                         \
+
+#define SAFE_SET(old, new) do {         \
+    PyObject *__simple_set_tmp = NULL;  \
+    __simple_set_tmp = old;             \
+    Py_INCREF(new);                     \
+    old = new;                          \
+    Py_XDECREF(__simple_set_tmp);       \
+} while(0);
+
+#endif /* __SSS_PYTHON_H__ */