WIP: GnuTLS: determine capabilities in autoconfscratch/tzz/nettle

3 files changed, 71 insertions, 10 deletions

diff --git a/configure.ac b/configure.ac
index 60f8f705f6a..bb68aa75328 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2828,9 +2828,61 @@ if test "${with_gnutls}" = "yes" ; then
     AC_DEFINE(HAVE_GNUTLS, 1, [Define if using GnuTLS.])
     EMACS_CHECK_MODULES([LIBGNUTLS3], [gnutls >= 3.0.0],
       [AC_DEFINE(HAVE_GNUTLS3, 1, [Define if using GnuTLS v3.])], [])
-      dnl TODO: check the relevant functions directly, this is not great
-    EMACS_CHECK_MODULES([LIBGNUTLS3_AEAD], [gnutls >= 3.4.0],
-      [AC_DEFINE(HAVE_GNUTLS3_AEAD, 1, [Define if using GnuTLS v3 with AEAD support.])], [])
+
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+]],
+[[
+int main (int argc, char **argv)
+{
+  gnutls_hmac_hd_t handle;
+  gnutls_hmac_deinit(handle, NULL);
+}
+]])],
+    [AC_DEFINE(HAVE_GNUTLS3_HMAC, 1, [Define if using GnuTLS v3 with HMAC support.])])
+
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+]],
+[[
+int main (int argc, char **argv)
+{
+    gnutls_aead_cipher_hd_t handle;
+    gnutls_aead_cipher_deinit(handle);
+}
+]])],
+    [AC_DEFINE(HAVE_GNUTLS3_AEAD, 1, [Define if using GnuTLS v3 with AEAD support.])])
+
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+]],
+[[
+int main (int argc, char **argv)
+{
+    gnutls_cipher_hd_t handle;
+    gnutls_cipher_encrypt2 (handle,
+                            NULL, 0,
+                            NULL, 0);
+    gnutls_cipher_deinit(handle);
+}
+]])],
+    [AC_DEFINE(HAVE_GNUTLS3_CIPHER, 1, [Define if using GnuTLS v3 with cipher support.])])
+
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+]],
+[[
+int main (int argc, char **argv)
+{
+    gnutls_hash_hd_t handle;
+    gnutls_hash_deinit(handle, NULL);
+}
+]])],
+    [AC_DEFINE(HAVE_GNUTLS3_DIGEST, 1, [Define if using GnuTLS v3 with digest support.])])
   fi
 
   # Windows loads GnuTLS dynamically
diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index e33b2b34d2b..fd6ddc98fed 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -4511,8 +4511,6 @@ It should be somewhat more efficient on larger buffers than
 @cindex symmetric cipher
 @cindex cipher, symmetric
 
-TODO: without autoconf macros, we have to require 3.4
-
 If compiled with GnuTLS, Emacs offers built-in cryptographic support.
 Following the GnuTLS API terminology, the available tools are digests,
 MACs, symmetric ciphers, and AEAD ciphers.
diff --git a/src/gnutls.c b/src/gnutls.c
index 4b44d96f638..7a4e92f0d3f 100644
--- a/src/gnutls.c
+++ b/src/gnutls.c
@@ -2315,16 +2315,27 @@ GnuTLS AEAD ciphers     : the list will contain 'AEAD-ciphers.  */)
 #ifdef HAVE_GNUTLS
   Lisp_Object capabilities = Qnil;
 
-  // TODO: fix the autoconf function-checking macros that will tell us for sure.
+#ifdef HAVE_GNUTLS3
+
+  capabilities = Fcons (intern("gnutls3"), capabilities);
+
+#ifdef HAVE_GNUTLS3_DIGEST
+  capabilities = Fcons (intern("digests"), capabilities);
+#endif
+
+#ifdef HAVE_GNUTLS3_CIPHER
+  capabilities = Fcons (intern("ciphers"), capabilities);
+
 #ifdef HAVE_GNUTLS3_AEAD
   capabilities = Fcons (intern("AEAD-ciphers"), capabilities);
 #endif
 
-#ifdef HAVE_GNUTLS3
-  capabilities = Fcons (intern("gnutls3"), capabilities);
-  capabilities = Fcons (intern("ciphers"), capabilities);
+#ifdef HAVE_GNUTLS3_HMAC
   capabilities = Fcons (intern("macs"), capabilities);
-  capabilities = Fcons (intern("digests"), capabilities);
+#endif
+
+#endif
+
 #endif
 
 # ifdef WINDOWSNT