skip duplicate util-vserver dir
[util-vserver.git] / m4 / ensc_syscall.m4
diff --git a/m4/ensc_syscall.m4 b/m4/ensc_syscall.m4
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+dnl $Id$
+
+dnl Copyright (C) 2004 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
+dnl  
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; version 2 of the License.
+dnl  
+dnl This program 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.  See the
+dnl GNU General Public License for more details.
+dnl  
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software
+dnl Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+dnl Usage: ENSC_SYSCALL
+
+AC_DEFUN([ENSC_SYSCALL_ALTERNATIVE],
+[
+       AC_MSG_CHECKING([whether to use alternative _syscallX macros])
+       AC_ARG_ENABLE([alternative-syscalls],
+                     [AC_HELP_STRING([--disable-alternative-syscalls],
+                                     [do not use the alternative _syscallX macros
+                                      provided by Herbert Poetzl (default: use them)])],
+                     [case $enableval in
+                          (yes|no)   ensc_use_alternative_syscall_macros=$enableval;;
+                          (*)        AC_MSG_ERROR(['$enableval' is not a valid value for '--disable-alternative-syscalls']);;
+                      esac],
+                      [ensc_use_alternative_syscall_macros=yes])
+
+       case $ensc_use_alternative_syscall_macros in
+               (yes)   AC_DEFINE(ENSC_USE_ALTERNATIVE_SYSCALL_MACROS, 1, [Use alternative _syscallX macros]);;
+       esac
+
+       AC_MSG_RESULT([$ensc_use_alternative_syscall_macros])
+])
+
+AC_DEFUN([ENSC_SYSCALL],
+[
+       AC_REQUIRE([ENSC_SYSCALL_ALTERNATIVE])
+
+        AC_MSG_CHECKING([for syscall(2) invocation method])
+        AC_ARG_WITH([syscall],
+                   [AC_HELP_STRING([--with-syscall=METHOD],
+                                    [call syscall(2) with the specified METHOD; valid values are 'fast', 'traditional' and 'auto' (default: auto)])],
+                    [],
+                    [with_syscall=auto])
+        AC_MSG_RESULT([$with_syscall])
+        
+        case x"$with_syscall" in
+            (xauto)
+               AC_CACHE_CHECK([which syscall(2) invocation works], [ensc_cv_test_syscall],
+                              [
+                               AC_LANG_PUSH(C)
+                               AC_COMPILE_IFELSE(AC_LANG_SOURCE([
+#include "$srcdir/lib/syscall-wrap.h"
+#include <errno.h>
+
+#define __NR_foo0      300
+#define __NR_foo1      301
+#define __NR_foo2      302
+#define __NR_foo3      303
+#define __NR_foo4      304
+#define __NR_foo5      305
+inline static _syscall0(int, foo0)
+inline static _syscall1(int, foo1, int, a)
+inline static _syscall2(int, foo2, int, a, int, b)
+inline static _syscall3(int, foo3, int, a, int, b, int, c)
+inline static _syscall4(int, foo4, int, a, int, b, int, c, int, d)
+inline static _syscall5(int, foo5, int, a, int, b, int, c, int, d, int, e)
+
+int main() {
+  return foo0() || \
+        foo1(1) || \
+        foo2(1,2) || \
+         foo3(1,2,3) || \
+         foo4(1,2,3,4) || \
+        foo5(1,2,3,4,5);
+}
+                               ]),
+                               [ensc_cv_test_syscall=fast],
+                               [ensc_cv_test_syscall=traditional])
+
+                               AC_LANG_POP
+               ])
+               with_syscall=$ensc_cv_test_syscall
+               ;;
+            (xfast|xtraditional)
+               ;;
+            *)
+               AC_MSG_ERROR(['$with_syscall' is not a valid value for '--with-syscall'])
+               ;;
+        esac
+
+       if test x"$with_syscall $ensc_use_alternative_syscall_macros" = 'xfast yes'; then
+           with_syscall='alternative'
+        fi
+
+        if test x"$with_syscall" = xtraditional; then
+            AC_DEFINE(ENSC_SYSCALL_TRADITIONAL,  1, [Define to 1 when the fast syscall(2) invocation does not work])
+        fi
+        
+        AH_BOTTOM([
+#if defined(__pic__) && defined(__i386) && !defined(ENSC_SYSCALL_TRADITIONAL) && !defined(ENSC_USE_ALTERNATIVE_SYSCALL_MACROS)
+#  define ENSC_SYSCALL_TRADITIONAL     1
+#endif])
+])