Add initial grab_file helper for http download support

tools/grab_file

@@ -0,0 +1,32 @@
+#!/bin/sh
+#
+# grab_file
+#
+# extra utility script - if a file does not exist in our mirror and
+# we've been told to use an http mirror, go grab it from there
+#
+# Takes 1 parameters: the the full path to the file (relative to the
+# base dir of the mirror)
+#
+# The MIRROR env var must be set
+# If we want to be able to download, HTTPMIRROR mus be set too
+
+set -e
+#set -x
+
+WANTED=$1
+
+if [ "$MIRROR"x = ""x ] ; then
+    echo $0: MIRROR not set
+    exit 1
+fi
+
+if [ -e "$MIRROR/$WANTED" ] ; then
+    exit 0
+fi
+
+# else
+
+DIR=$(dirname "$WANTED")
+mkdir -p "$MIRROR/$DIR"
+wget -o /tmp/log -q "$HTTPMIRROR/$WANTED" -O "$MIRROR/$WANTED"