dnl -------------------------------------------------------------------------
dnl       $Id$
dnl
dnl       tls.m4
dnl
dnl       ACE M4 include file which contains ACE specific M4 macros
dnl       that determine availablility of SSL/TLS support.
dnl
dnl -------------------------------------------------------------------------

dnl  Copyright (C) 2003  Ossama Othman
dnl
dnl  All Rights Reserved
dnl
dnl This library is free software; you can redistribute it and/or
dnl modify it under the current ACE distribution terms.
dnl
dnl This library is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

dnl TLS/SSL library IO check
dnl Use this macro to determine if TLS/SSL support is available on the
dnl current host.
dnl Usage: ACE_CHECK_TLS
AC_DEFUN([ACE_CHECK_TLS],
[
 AC_REQUIRE([AC_PROG_CXX])
 AC_REQUIRE([AC_PROG_CXXCPP])
 AC_LANG([C++])
 AC_REQUIRE([AC_LANG])

 dnl Save the current library and preprocessor flagslist.  We do not
 dnl want to add the SSL/TLS-specific ones to the general library link
 dnl and preprocessor flags list since they should only be used when
 dnl building the ACE_SSL library and/or binaries that use the ACE_SSL
 dnl library.
 ace_save_LIBS="$LIBS"
 ace_save_CPPFLAGS="$CPPFLAGS"

 dnl ---------------------------------------------------------

 ace_TLS_CPPFLAGS=""

 dnl Check if OpenSSL requires the Kerberos include directory to be
 dnl added to the header search path.

 AC_CACHE_CHECK([for Kerberos include flags needed by OpenSSL],
 [ac_cv_kerberos_dir],
 [
  for ace_kerberos in usr usr/local; do
   ace_TLS_CPPFLAGS="-I/${ace_kerberos}/kerberos/include"

   CPPFLAGS="$ace_TLS_CPPFLAGS $ace_save_CPPFLAGS"

   AC_COMPILE_IFELSE([
     AC_LANG_PROGRAM([
#include <openssl/ssl.h>
     ],
     [
// ... THIS CODE DOES NOTHING!  IT IS JUST USED FOR COMPILE TESTS ...

// ... Perform TCP connection ...

// ... Perform TLS/SSL stuff ...
CRYPTO_set_locking_callback (0);
SSLeay_add_ssl_algorithms ();
SSL_load_error_strings ();
SSL_METHOD * meth = TLSv1_method ();
SSL_CTX * ctx = SSL_CTX_new (meth);
SSL * ssl = SSL_new (ctx);
int fd = 2000;  // Dummy file descriptor value.
SSL_set_fd (ssl, fd);
SSL_connect (ssl);
SSL_shutdown (ssl);

// ...
     ])
   ],
   [
    ac_cv_kerberos_dir="$ace_TLS_CPPFLAGS"
    break
   ],
   [
    ac_cv_kerberos_dir=no
   ])

  done
 ])

 if test $ac_cv_kerberos_dir != no; then
    AC_SUBST([ACE_TLS_CPPFLAGS],[$ace_TLS_CPPFLAGS])
 fi   

 dnl ---------------------------------------------------------

 dnl Add the TLS/SSL libraries to the library list.
 ace_TLS_LIBS="-lssl -lcrypto"

 LIBS="$ace_TLS_LIBS $LIBS"

 AC_CACHE_CHECK([for OpenSSL libraries],
 [ac_cv_openssl_libs],
 [
  AC_LINK_IFELSE([
   AC_LANG_PROGRAM([
#include <openssl/ssl.h>
   ],
   [
// ... THIS PROGRAM DOES NOTHING!  IT IS JUST USED FOR LINK TESTS ...

// ... Perform TCP connection ...

// ... Perform TLS/SSL stuff ...
CRYPTO_set_locking_callback (0);
SSLeay_add_ssl_algorithms ();
SSL_load_error_strings ();
SSL_METHOD * meth = TLSv1_method ();
SSL_CTX * ctx = SSL_CTX_new (meth);
SSL * ssl = SSL_new (ctx);
int fd = 2000;  // Dummy file descriptor value.
SSL_set_fd (ssl, fd);
SSL_connect (ssl);
SSL_shutdown (ssl);

// ...
   ])
  ],
  [
   ac_cv_openssl_libs=yes
  ],
  [
   ac_cv_openssl_libs=no
  ])
 ])

 if test $ac_cv_openssl_libs != no; then
   AC_SUBST([ACE_TLS_LIBS],[$ace_TLS_LIBS])
 fi   

 AM_CONDITIONAL([BUILD_SSL], [test X$ace_user_with_ssl = Xyes])

 dnl Restore the original library list and preprocessor flags.
 LIBS="$ace_save_LIBS"
 CPPFLAGS="$ace_save_CPPFLAGS"

])