datapath: Fix build with kernel header layout recently adopted by Debian.

Recent Debian kernel-header packages divide kernel headers into two
directories: the "common" headers that are not architecture-specific,
which go in a directory named like
    /usr/src/kernel-headers-2.6.31-1-common,
and architecture-specific headers in a directory named, e.g.
    /usr/src/kernel-headers-2.6.31-1-686.
OVS needs to look at the ones in the "common" directory as part of its
configuration process, but the build directory provided on --with-l26 is
the architecture-specific directory.  We also need the
architecture-specific directory, since it is the one that we use as part
of the "make", so we can't simply make the user specify the common
directory on --with-l26.  Furthermore, there is no easy-to-see link
between the two directories, except as part of the text in a Makefile,
which is not the easiest language to parse.

This commit attempts to kluge around the problem by using the Debian
directory naming.  If the build directory does not contain the headers,
then we replace the last component of its name by "-common" and check
for the headers there.  This is not ideal, but it does solve the actual
problem at hand.

Tested with Debian's linux-headers-2.6.31-1-686 and with a few older
sets of headers that do not use this scheme.

diff --git a/acinclude.m4 b/acinclude.m4
index 6ba647ab96183313133f11881aa9620c51c3c830..611566900f178d8ffc7f153f479438977c894b6f 100644 (file)
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -14,41 +14,62 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-dnl OVS_CHECK_LINUX(OPTION, VERSION, VARIABLE, CONDITIONAL)
+dnl OVS_CHECK_LINUX26
 dnl
 dnl Configure linux kernel source tree 
-AC_DEFUN([OVS_CHECK_LINUX], [
-  AC_ARG_WITH([$1],
-              [AC_HELP_STRING([--with-$1=/path/to/linux-$2],
-                              [Specify the linux $2 kernel sources])],
-              [path="$withval"], [path=])dnl
-  if test -n "$path"; then
-    path=`eval echo "$path"`
+AC_DEFUN([OVS_CHECK_LINUX26], [
+  AC_ARG_WITH([l26],
+              [AC_HELP_STRING([--with-l26=/path/to/linux-2.6],
+                              [Specify the linux 2.6 kernel sources])],
+              [KBUILD26="$withval"], [KBUILD26=])dnl
+  if test -n "$KBUILD26"; then
+    KBUILD26=`eval echo "$KBUILD26"`
 
-    AC_MSG_CHECKING([for $path directory])
-    if test -d "$path"; then
-       AC_MSG_RESULT([yes])
-       $3=$path
-       AC_SUBST($3)
+    # The build directory is what the user provided.
+    # Make sure that it exists.
+    AC_MSG_CHECKING([for Linux 2.6 build directory])
+    if test -d "$KBUILD26"; then
+       AC_MSG_RESULT([$KBUILD26])
+       AC_SUBST(KBUILD26)
     else
        AC_MSG_RESULT([no])
-       AC_ERROR([source dir $path doesn't exist])
+       AC_ERROR([source dir $KBUILD26 doesn't exist])
     fi
 
-    AC_MSG_CHECKING([for $path kernel version])
-    patchlevel=`sed -n 's/^PATCHLEVEL = //p' "$path/Makefile"`
-    sublevel=`sed -n 's/^SUBLEVEL = //p' "$path/Makefile"`
+    # Debian breaks kernel headers into "source" header and "build" headers.
+    # We want the source headers, but $KBUILD26 gives us the "build" headers.
+    # Use heuristics to find the source headers.
+    AC_MSG_CHECKING([for Linux 2.6 source directory])
+    KSRC26=$KBUILD26
+    if test ! -e $KSRC26/include/linux/kernel.h; then
+      KSRC26=`(cd $KBUILD26 && pwd -P) | sed 's,-[[^-]]*$,-common,'`
+      if test ! -e $KSRC26/include/linux/kernel.h; then
+        AC_MSG_ERROR([cannot find source directory])
+      fi
+    fi
+    AC_MSG_RESULT([$KSRC26])
+
+    AC_MSG_CHECKING([for kernel version])
+    patchlevel=`sed -n 's/^PATCHLEVEL = //p' "$KSRC26/Makefile"`
+    sublevel=`sed -n 's/^SUBLEVEL = //p' "$KSRC26/Makefile"`
+    if test -z "$patchlevel" || test -z "$sublevel"; then
+       AC_ERROR([cannot determine kernel version])
+    fi
     AC_MSG_RESULT([2.$patchlevel.$sublevel])
-    if test "2.$patchlevel" != '$2'; then
-       AC_ERROR([Linux kernel source in $path is not version $2])
+    if test "2.$patchlevel" != '2.6'; then
+       if test "$BUILD26" = "$KSRC26"; then
+         AC_ERROR([Linux kernel in $KBUILD26 is not version 2.6])
+       else
+         AC_ERROR([Linux kernel in build tree $KBUILD26 (source tree $KSRC26) is not version 2.6])
+       fi
     fi
-    if ! test -e "$path"/include/linux/version.h || \
-       ! test -e "$path"/include/linux/autoconf.h; then
-       AC_MSG_ERROR([Linux kernel source in $path is not configured])
+    if ! test -e "$KBUILD26"/include/linux/version.h || \
+       ! test -e "$KBUILD26"/include/linux/autoconf.h; then
+       AC_MSG_ERROR([Linux kernel source in $KBUILD26 is not configured])
     fi
-    m4_if($2, [2.6], [OVS_CHECK_LINUX26_COMPAT])
+    OVS_CHECK_LINUX26_COMPAT
   fi
-  AM_CONDITIONAL($4, test -n "$path")
+  AM_CONDITIONAL(L26_ENABLED, test -n "$KBUILD26")
 ])
 
 dnl OVS_GREP_IFELSE(FILE, REGEX, IF-MATCH, IF-NO-MATCH)
@@ -103,7 +124,7 @@ AC_DEFUN([OVS_CHECK_LOG2_H], [
 dnl OVS_CHECK_LINUX26_COMPAT
 dnl
 dnl Runs various Autoconf checks on the Linux 2.6 kernel source in
-dnl the directory in $KSRC26.
+dnl the directory in $KBUILD26.
 AC_DEFUN([OVS_CHECK_LINUX26_COMPAT], [
   rm -f datapath/linux-2.6/kcompat.h.new
   mkdir -p datapath/linux-2.6

diff --git a/configure.ac b/configure.ac
index c8eed7c970083348bcefbf2f18545e4e4f5a4840..300b21e2cdb6d1506c7e7ea36c562984c47a9063 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -78,7 +78,7 @@ OVS_ENABLE_OPTION([-Wno-override-init])
 
 AC_ARG_VAR(KARCH, [Kernel Architecture String])
 AC_SUBST(KARCH)
-OVS_CHECK_LINUX(l26, 2.6, KSRC26, L26_ENABLED)
+OVS_CHECK_LINUX26
 
 AC_CONFIG_FILES([Makefile 
 datapath/Makefile 

diff --git a/datapath/linux-2.6/Makefile.main.in b/datapath/linux-2.6/Makefile.main.in
index 0005ec4fa03c3211908b19540901dcd02f11ac89..967e2f7bcff1953fffbcb3d5c1e3c2ebdbc3b2f1 100644 (file)
--- a/datapath/linux-2.6/Makefile.main.in
+++ b/datapath/linux-2.6/Makefile.main.in
@@ -2,7 +2,7 @@
 export builddir = @abs_builddir@
 export srcdir = @abs_srcdir@
 export top_srcdir = @abs_top_srcdir@
-export KSRC = @KSRC26@
+export KSRC = @KBUILD26@
 export VERSION = @VERSION@
 export BUILD_VETH = @BUILD_VETH@