From 441b30f89ff9db986c4a6bf6c15e8fd226f79b30 Mon Sep 17 00:00:00 2001
From: Adam Gandelman <adamg@ubuntu.com>
Date: Wed, 10 Dec 2014 15:36:15 -0800
Subject: [PATCH] Fallback to a boot_server kernel param if ip=  not passed

Depending on bootloader and configuration, ramdisks may receive
a ip= kernel parameter that is used for manual network bring up
in the ramdisk.  This parameter contains the address of the boot
server.  In the absence of ip=, we want the ramdisk to DHCP and
proceed as normal.  However, in this case need to know the address
of the boot server.  This falls back to a 'boot_server' parameter
for this address if it is not provided via kernel cmdline.

Change-Id: Id1ed15ba125d91fa0a13d8e19d1385082ee5d9e9
Closes-bug: #1401289
Related-bug: #1401298
---
 elements/ramdisk-base/init.d/20-init-variables | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/elements/ramdisk-base/init.d/20-init-variables b/elements/ramdisk-base/init.d/20-init-variables
index dee7c7a9a..405b25633 100644
--- a/elements/ramdisk-base/init.d/20-init-variables
+++ b/elements/ramdisk-base/init.d/20-init-variables
@@ -18,7 +18,14 @@ readonly _BOOTIF_=$(get_kernel_parameter BOOTIF)
 readonly _IP_=$(get_kernel_parameter ip)
 readonly BOOT_MAC_ADDRESS=$(echo "$_BOOTIF_" | sed -e "s/-/:/g" | \
                             sed -e "s/^01://g" | tr 'a-f' 'A-F')
-readonly BOOT_SERVER=$(echo "$_IP_" | cut -d':' -f2)
+
+# If bootloader did not pass on network info, we fallback to a kernel
+# parameter to locate the address of the boot server.
+if [ -n "$_IP_" ]; then
+    readonly BOOT_SERVER=$(echo "$_IP_" | cut -d':' -f2)
+else
+    readonly BOOT_SERVER=$(get_kernel_parameter boot_server)
+fi
 
 # IP address, netmask, gateway can be set a later point of time if
 # IP address is assigned by dhcp (for non-pxe boots).