[PATCH] adt-build-lxc: don't hardcode bridge interface

[terceiro@debian.org (Antonio Terceiro)]

---
 tools/adt-build-lxc | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/adt-build-lxc b/tools/adt-build-lxc
index 97c387f..9002fc1 100755
--- a/tools/adt-build-lxc
+++ b/tools/adt-build-lxc
@@ -62,11 +62,20 @@ proxy_detect() {
         if echo "$proxy" | egrep -q '(localhost|127\.0\.0\.[0-9]*):3142'; then
             # set http_proxy for the initial debootstrap
             export http_proxy="$proxy"
-            local bridge_ip=$(ip -4 a show dev lxcbr0 | awk '/ inet / {sub(/\/.*$/, "", $2); print $2}') || true
-            if [ -n "$bridge_ip" ]; then
-                ADT_APT_PROXY="http://$bridge_ip:3142";
+
+            # translate proxy address to one that can be accessed from the
+            # running container
+            local bridge_interface=$(awk '{ if ($1 == "lxc.network.link") print($3)}' /etc/lxc/default.conf)
+            if [ -n "$bridge_interface" ]; then
+                local bridge_ip=$(ip -4 a show dev "$bridge_interface" | awk '/ inet / {sub(/\/.*$/, "", $2); print $2}') || true
+                if [ -n "$bridge_ip" ]; then
+                    ADT_APT_PROXY="http://$bridge_ip:3142";
+                fi
+            fi
+            echo "Detected apt-cacher-ng. Using local proxy $http_proxy"
+            if [ -n "$ADT_APT_PROXY" ]; then
+                echo "Using $ADT_APT_PROXY as container proxy"
             fi
-            echo "Detected apt-cacher-ng. Using local proxy $http_proxy, container proxy $ADT_APT_PROXY"
         fi
     fi
 }
-- 
2.6.2