Do not attempt a DKMS build if the headers aren't available

* Do not attempt to build the kernel module with DKMS if the appropriate
  Linux headers aren't installed.  Based on code from the common DKMS
  postinst script (which we'll just use once it's reliably available).
  Thanks, Anders Kaseorg.  (LP: #487535)

(cherry picked from commit 649adcdb8d13c1da9e533483ba9a2f7be221dcd8)

diff --git a/debian/openafs-modules-dkms.postinst b/debian/openafs-modules-dkms.postinst
index 556dbf710f3dabfba97a3664a55d8b0901d1838f..5a6d5f44789e82e156e9c927c7c23f603be2affd 100644 (file)
--- a/debian/openafs-modules-dkms.postinst
+++ b/debian/openafs-modules-dkms.postinst
@@ -6,6 +6,7 @@ set -e
 package=openafs-modules-dkms
 version=`dpkg-query -W -f='${Version}' "$package" \
     | sed -e 's/[+-].*//' -e 's/\.dfsg.*//' -e 's/~//g'`
+kernel=`uname -r`
 
 # If someone installed this package without the necessary kernel headers, the
 # postinst will fail.  If they then fix this problem, the postinst will keep
@@ -16,8 +17,19 @@ if [ -e "/var/lib/dkms/openafs/$version" ] ; then
 fi
 dkms add -m openafs -v "$version"
 if [ "$1" = 'configure' ] ; then
-    dkms build -m openafs -v "$version"
-    dkms install -m openafs -v "$version" --force
+    if [ -e "/lib/modules/$kernel/build/include" ] ; then
+        dkms build -m openafs -v "$version"
+        dkms install -m openafs -v "$version" --force
+    else
+        cat >&2 <<"EOF"
+
+The OpenAFS module build for the currently running kernel was skipped since
+the kernel headers for this kernel do not seem to be installed.  To build
+the kernel module, install the appropriate kernel headers package for your
+kernel (usually linux-headers-$kernel).
+
+EOF
+    fi
 fi
 
 #DEBHELPER#