hmac: use EVP_MD_CTX_get_pkey_ctx() instead of EVP_MD_CTX_pkey_ctx()

OpenSSL 3.0 renamed EVP_MD_CTX_pkey_ctx() to include "get" in the
function name. Adjust compatibility macro so that we can use the new
function name for all OpenSSL 1.0.2-3.0.

Author: rhenium

ext/openssl/extconf.rb

@@ -177,6 +177,7 @@ def find_openssl_library
 have_func("SSL_CTX_load_verify_file")
 have_func("BN_check_prime")
 have_func("EVP_MD_CTX_get0_md")
+have_func("EVP_MD_CTX_get_pkey_ctx")
 
 Logging::message "=== Checking done. ===\n"
 

ext/openssl/openssl_missing.h

@@ -21,10 +21,6 @@
 #  define EVP_MD_CTX_free EVP_MD_CTX_destroy
 #endif
 
-#if !defined(HAVE_EVP_MD_CTX_PKEY_CTX)
-#  define EVP_MD_CTX_pkey_ctx(x) (x)->pctx
-#endif
-
 #if !defined(HAVE_X509_STORE_GET_EX_DATA)
 #  define X509_STORE_get_ex_data(x, idx) \
 	CRYPTO_get_ex_data(&(x)->ex_data, (idx))
@@ -223,4 +219,16 @@ IMPL_PKEY_GETTER(EC_KEY, ec)
 #  define EVP_MD_CTX_get0_md(ctx) EVP_MD_CTX_md(ctx)
 #endif
 
+/*
+ * OpenSSL 1.1.0 added EVP_MD_CTX_pkey_ctx(), and then it was renamed to
+ * EVP_MD_CTX_get_pkey_ctx(x) in OpenSSL 3.0.
+ */
+#ifndef HAVE_EVP_MD_CTX_GET_PKEY_CTX
+# ifdef HAVE_EVP_MD_CTX_PKEY_CTX
+#  define EVP_MD_CTX_get_pkey_ctx(x) EVP_MD_CTX_pkey_ctx(x)
+# else
+#  define EVP_MD_CTX_get_pkey_ctx(x) (x)->pctx
+# endif
+#endif
+
 #endif /* _OSSL_OPENSSL_MISSING_H_ */

ext/openssl/ossl_hmac.c

@@ -238,7 +238,7 @@ ossl_hmac_reset(VALUE self)
     EVP_PKEY *pkey;
 
     GetHMAC(self, ctx);
-    pkey = EVP_PKEY_CTX_get0_pkey(EVP_MD_CTX_pkey_ctx(ctx));
+    pkey = EVP_PKEY_CTX_get0_pkey(EVP_MD_CTX_get_pkey_ctx(ctx));
     if (EVP_DigestSignInit(ctx, NULL, EVP_MD_CTX_get0_md(ctx), NULL, pkey) != 1)
         ossl_raise(eHMACError, "EVP_DigestSignInit");