From d2f00fd2af9417a91c78e9cab5747cd6e218aa39 Mon Sep 17 00:00:00 2001
From: Scott Moser <smoser@ubuntu.com>
Date: Thu, 13 Sep 2012 20:02:37 -0400
Subject: only emit if there is a device present.

---
 upstart/cloud-init-container.conf | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/upstart/cloud-init-container.conf b/upstart/cloud-init-container.conf
index b3123721..497e75c8 100644
--- a/upstart/cloud-init-container.conf
+++ b/upstart/cloud-init-container.conf
@@ -27,13 +27,23 @@ script
    set -- ${auto_list}
    [ "$*" = "lo" ] && exit 0
 
-   to_emit=""
+   # we only want to emit for interfaces that do not exist, so filter
+   # out anything that does not exist.
    for iface in "$@"; do
       [ "$iface" = "lo" ] && continue
       # skip interfaces that are already up
       [ -f "${MARK_DEV_PREFIX}${iface}" ] && continue
+
+      if [ -d /sys/net ]; then
+         # if /sys is mounted, and there is no /sys/net/iface, then no device
+         [ -e "/sys/net/$iface" ] && continue
+      else
+         # sys wasn't mounted, so just check via 'ifconfig'
+         ifconfig "$iface" >/dev/null 2>&1 || continue
+      fi 
       initctl emit --no-wait net-device-added "INTERFACE=$iface" &&
-         emitted="${emitted} ${iface}" || :
+         emitted="$emitted $iface" ||
+         echo "warn: ${UPSTART_JOB} failed to emit net-device-added INTERFACE=$iface"
    done
 
    [ -z "${emitted# }" ] ||
-- 
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