# Based on gssapi.m4 by Brendan Cully <brendan@kublai.com> 20010529

dnl MU_CHECK_GSSAPI(PREFIX)
dnl Search for a GSSAPI implementation in the standard locations plus PREFIX,
dnl if it is set and not "yes".
dnl Defines GSSAPI_CFLAGS and GSSAPI_LIBS if found.
dnl Defines GSSAPI_IMPL to "GSS", "Heimdal", "MIT", or "OldMIT", or
dnl "none" if not found

AC_DEFUN([MU_CHECK_GSSAPI],
[
 if test "x$mu_cv_lib_gssapi_libs" = x; then
  cached=""
  GSSAPI_PREFIX=[$1]
  GSSAPI_IMPL="none"
  # First try krb5-config
  case $GSSAPI_PREFIX in
  yes|probe) krb5_path="$PATH";;
  *)   krb5_path="$GSSAPI_PREFIX/bin"
  esac
  AC_PATH_PROG(KRB5CFGPATH, krb5-config, none, $krb5_path)
  AC_CHECK_HEADER(gss.h, [wantgss=yes], [wantgss=no])
  if test $wantgss != no; then
    save_LIBS=$LIBS
    AC_CHECK_LIB(gss, gss_check_version, [GSSAPI_LIBS=-lgss], [wantgss=no])
    if test $wantgss != no; then
      LIBS="$LIBS $GSSAPI_LIBS"
      AC_TRY_RUN([
#include <gss.h>
int main() { return gss_check_version ("0.0.9") == (char*) 0; }],
                 [:],
                 [wantgss=no],
                 [wantgss=no])
    fi
    LIBS=$save_LIBS
  fi
  if test $wantgss != no; then
    GSSAPI_IMPL="GSS"
    AC_DEFINE(WITH_GSS,1,[Define if mailutils is using GSS library for GSSAPI])
  elif test "$KRB5CFGPATH" != "none"; then
    GSSAPI_CFLAGS="$CPPFLAGS `$KRB5CFGPATH --cflags gssapi`"
    GSSAPI_LIBS="`$KRB5CFGPATH --libs gssapi`"
    GSSAPI_IMPL="Heimdal"
  else
    ## OK, try the old code
    saved_CPPFLAGS="$CPPFLAGS"
    saved_LDFLAGS="$LDFLAGS"
    saved_LIBS="$LIBS"
    case $GSSAPI_PREFIX in
    yes|probe) ;;
    *)
      GSSAPI_CFLAGS="-I$GSSAPI_PREFIX/include"
      GSSAPI_LDFLAGS="-L$GSSAPI_PREFIX/lib"
      CPPFLAGS="$CPPFLAGS $GSSAPI_CFLAGS"
      LDFLAGS="$LDFLAGS $GSSAPI_LDFLAGS"
    esac

    ## Check for new MIT kerberos V support
    AC_CHECK_LIB(gssapi_krb5, gss_init_sec_context,
      [GSSAPI_IMPL="MIT",
       GSSAPI_LIBS="$GSSAPI_LDFLAGS -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err"]
       ,, -lkrb5 -lk5crypto -lcom_err)

    ## Heimdal kerberos V support
    if test "$GSSAPI_IMPL" = "none"; then
      AC_CHECK_LIB(gssapi, gss_init_sec_context,
        [GSSAPI_IMPL="Heimdal"
         GSSAPI_LDFLAGS="$GSSAPI_LDFLAGS -lgssapi -lkrb5 -ldes -lasn1 -lroken"
         GSSAPI_LIBS="$GSSAPI_LDFLAGS -lcrypt -lcom_err"]
         ,, -lkrb5 -ldes -lasn1 -lroken -lcrypt -lcom_err)
    fi

    ## Old MIT Kerberos V
    ## Note: older krb5 distributions use -lcrypto instead of
    ## -lk5crypto, which collides with OpenSSL.  One way of dealing
    ## with that is to extract all objects from krb5's libcrypto
    ## and from openssl's libcrypto into the same directory, then
    ## to create a new libcrypto from these.
    if test "$GSSAPI_IMPL" = "none"; then
      AC_CHECK_LIB(gssapi_krb5, g_order_init,
        [GSSAPI_IMPL="OldMIT",
        GSSAPI_LIBS="$GSSAPI_LDFLAGS -lgssapi_krb5 -lkrb5 -lcrypto -lcom_err"]
        ,, -lkrb5 -lcrypto -lcom_err)
    fi

    CPPFLAGS="$saved_CPPFLAGS"
    LDFLAGS="$saved_LDFLAGS"
    LIBS="$saved_LIBS"
  fi

  saved_CPPFLAGS="$CPPFLAGS"
  CPPFLAGS="$CPPFLAGS $GSSAPI_CFLAGS"
  AC_CHECK_HEADERS(gssapi.h gssapi/gssapi.h gssapi/gssapi_generic.h)
  AC_CHECK_DECL(GSS_C_NT_HOSTBASED_SERVICE,, [
                AC_DEFINE(GSS_C_NT_HOSTBASED_SERVICE,
                          gss_nt_service_name,
                          [Work around buggy MIT library])],[
#ifdef WITH_GSS
# include <gss.h>
#else
# ifdef HAVE_GSSAPI_H
#  include <gssapi.h>
# else
#  ifdef HAVE_GSSAPI_GSSAPI_H
#   include <gssapi/gssapi.h>
#  endif
#  ifdef HAVE_GSSAPI_GSSAPI_GENERIC_H
#   include <gssapi/gssapi_generic.h>
#  endif
# endif
#endif
])    
  CPPFLAGS="$saved_CPPFLAGS"

  mu_cv_lib_gssapi_cflags="$GSSAPI_CFLAGS"
  mu_cv_lib_gssapi_libs="$GSSAPI_LIBS"
  mu_cv_lib_gssapi_impl="$GSSAPI_IMPL"

 else
  cached=" (cached) "
  GSSAPI_CFLAGS="$mu_cv_lib_gssapi_cflags"
  GSSAPI_LIBS="$mu_cv_lib_gssapi_libs"
  GSSAPI_IMPL="$mu_cv_lib_gssapi_impl"
 fi
 AC_MSG_CHECKING(GSSAPI implementation)
 AC_MSG_RESULT(${cached}$GSSAPI_IMPL)
])