generate setns syscall number

config/linux.m4

+AC_DEFUN([AC_LINUX],
+[
+	AC_LINUX_DIR()
+	AC_LINUX_SRCARCH()
+])
+
+AC_DEFUN([AS_TRY_LINUX_DIR],
+	[AC_MSG_CHECKING(for Linux in $1)
+
+	if test -f "$1/Makefile" ; then
+		result=yes
+		$2
+	else
+		result="not found"
+		$3
+	fi
+
+	AC_MSG_RESULT($result)
+])
+
+AC_DEFUN([AC_LINUX_DIR],
+[
+	AC_ARG_WITH([linuxdir],
+		[AC_HELP_STRING([--with-linuxdir=DIR],
+			[specify path to Linux source directory])],
+		[LINUX_DIR="${withval}"],
+		[LINUX_DIR=default])
+
+	dnl if specified, use the specified one
+	if test "${LINUX_DIR}" != "default" ; then
+		AS_TRY_LINUX_DIR([${LINUX_DIR}], , AC_MSG_ERROR([Linux dir not found]) )
+	fi
+
+	dnl if not specified, first try with previously set LINUX_KERNEL_RELEASE
+	if test "${LINUX_DIR}" = "default" ; then
+		dir="/lib/modules/$LINUX_KERNEL_RELEASE/build";
+		AS_TRY_LINUX_DIR([${dir}], [LINUX_DIR=${dir}], )
+	fi
+
+	dnl next try using the kernel source dir
+	if test "${LINUX_DIR}" = "default" ; then
+		dir="/usr/src/linux-$LINUX_KERNEL_RELEASE";
+		AS_TRY_LINUX_DIR([${dir}], [LINUX_DIR=${dir}], )
+	fi
+
+	dnl then try a common default of /usr/src/linux
+	if test "${LINUX_DIR}" = "default" ; then
+		dir="/usr/src/linux";
+		AS_TRY_LINUX_DIR([${dir}], [LINUX_DIR=${dir}], )
+	fi
+
+	dnl if still nothing found, fail
+	if test "${LINUX_DIR}" = "default" ; then
+		AC_MSG_WARN([Linux source directory not found])
+	fi
+
+	AC_SUBST(LINUX_DIR)
+])
+
+AC_DEFUN([AC_LINUX_SRCARCH],[
+	AC_MSG_CHECKING(for linux SRCARCH)
+
+	case "${host}" in
+	i[[3456]]86-*) LINUX_SRCARCH=x86;;
+	x86_64-*) LINUX_SRCARCH=x86;;
+	powerpc*-*) LINUX_SRCARCH=powerpc;;
+	s390*-*) LINUX_SRCARCH=s390;;
+	*) AC_MSG_ERROR([architecture ${host} not supported]);;
+	esac
+
+	AC_MSG_RESULT(${LINUX_SRCARCH})
+	AC_SUBST(LINUX_SRCARCH)
+])

configure.ac

@@ -91,6 +91,8 @@ AC_CHECK_HEADERS([sys/signalfd.h])
 
 AC_PROG_GCC_TRADITIONAL
 
+AC_LINUX
+
 if test "x$GCC" = "xyes"; then
   CFLAGS="$CFLAGS -Wall"
 fi

src/lxc/Makefile.am

@@ -11,7 +11,8 @@ pkginclude_HEADERS = \
 		conf.h \
 		list.h \
 		log.h \
-		state.h
+		state.h \
+		setns.h
 
 sodir=$(libdir)
 # use PROGRAMS to avoid complains from automake
@@ -120,3 +121,14 @@ install-exec-local: install-soPROGRAMS
 
 uninstall-local:
 	$(RM) $(DESTDIR)$(libdir)/liblxc.so*
+
+namespace.c: setns.h
+
+setns.h:
+	-$(CC) $(CPPFLAGS) -M -MT$@ $(LINUX_DIR)/arch/$(LINUX_SRCARCH)/include/asm/unistd.h >setns.P
+	-$(CPP) $(CPPFLAGS) -dM $(LINUX_DIR)/arch/$(LINUX_SRCARCH)/include/asm/unistd.h |grep setns > $@
+
+clean-local:
+	$(RM) setns.h setns.P
+
+-include setns.P

src/lxc/namespace.c

@@ -34,19 +34,7 @@
 #include "namespace.h"
 #include "log.h"
 
-#ifndef __NR_setns
-#  if __i386__
-#    define __NR_setns 338
-#  elif __x86_64__
-#    define __NR_setns 300
-#  elif __powerpc__
-#    define __NR_setns 323
-#  elif __s390__
-#    define __NR_setns 332
-#  else
-#    warning "architecture not supported for setns"
-#  endif
-#endif
+#include "setns.h"
 
 lxc_log_define(lxc_namespace, lxc);