d-s-h: add safety check for unmask

1 files changed, 5 insertions, 1 deletions

diff --git a/script/deb-systemd-helper b/script/deb-systemd-helper
index 18ca4a4..c11f30f 100755
--- a/script/deb-systemd-helper
+++ b/script/deb-systemd-helper
@@ -416,7 +416,11 @@ sub unmask_service {
 
         my @entries = state_file_entries($statefile);
 
-        unlink($service_link) if -l $service_link;
+        if (! -l $service_link || readlink($service_link) ne '/dev/null') {
+            debug "Not unmasking $service_link because it is not a link to /dev/null";
+            next;
+        }
+        unlink($service_link);
 
         if (@entries > 0) {
             my $service_path = $entries[0];