runqemu: Add error handling for unexpected tap devices

In theory the code reduces the tap device number to an integer. This
patch adds error checking to ensure that does happen and that the script
exits if something unexpected happens.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/scripts/runqemu-internal b/scripts/runqemu-internal
index 03b40d83233ddbf41538157a3120726a6458d488..0ace485cb88ea1079e1d46262052d205e9d25011 100755 (executable)
--- a/scripts/runqemu-internal
+++ b/scripts/runqemu-internal
@@ -253,6 +253,14 @@ else
 
 
         n0=$(echo $TAP | sed 's/tap//')
+
+        case $n0 in
+            ''|*[!0-9]*)
+                echo "Error Couldn't turn $TAP into an interface number?"
+                exit 1
+                ;;
+        esac
+
         n1=$(($n0 * 2 + 1))
         n2=$(($n1 + 1))