From e9603e27bfd3e5e4c9432c6cb93ee405a6b41398 Mon Sep 17 00:00:00 2001
From: Flaviu Tamas <tamasflaviu@gmail.com>
Date: Fri, 24 Aug 2018 02:01:04 -0400
Subject: [PATCH] Build certgen in py3

---
 src/calibre/utils/certgen.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/src/calibre/utils/certgen.c b/src/calibre/utils/certgen.c
index 2770156c38..2ef066a720 100644
--- a/src/calibre/utils/certgen.c
+++ b/src/calibre/utils/certgen.c
@@ -379,15 +379,36 @@ static PyMethodDef certgen_methods[] = {
 };
 
 
-CALIBRE_MODINIT_FUNC
-initcertgen(void) {
-    PyObject *m;
-    m = Py_InitModule3("certgen", certgen_methods,
-    "OpenSSL bindings to easily create certificates/certificate authorities"
-    );
-    if (m == NULL) return;
+#if PY_MAJOR_VERSION >= 3
+#define INITERROR return NULL
+static struct PyModuleDef certgen_module = {
+    /* m_base     */ PyModuleDef_HEAD_INIT,
+    /* m_name     */ "certgen",
+    /* m_doc      */ "OpenSSL bindings to easily create certificates/certificate authorities.",
+    /* m_size     */ -1,
+    /* m_methods  */ certgen_methods,
+    /* m_slots    */ 0,
+    /* m_traverse */ 0,
+    /* m_clear    */ 0,
+    /* m_free     */ 0,
+};
+
+CALIBRE_MODINIT_FUNC PyInit_certgen(void) {
+    PyObject *mod = PyModule_Create(&certgen_module);
+#else
+#define INITERROR return
+CALIBRE_MODINIT_FUNC initcertgen(void) {
+    PyObject *mod = Py_InitModule3("certgen", certgen_methods,
+        "OpenSSL bindings to easily create certificates/certificate authorities");
+#endif
+
+    if (mod == NULL) INITERROR;
+
     OpenSSL_add_all_algorithms();
     ERR_load_crypto_strings();
     ERR_load_BIO_strings();
-}
 
+#if PY_MAJOR_VERSION >= 3
+    return mod;
+#endif
+}