From 1df3edbee59a60ca0bd7005124c12e99205fd2d1 Mon Sep 17 00:00:00 2001
From: Tom Hughes <tom@compton.nu>
Date: Thu, 27 Aug 2015 19:50:03 +0100
Subject: [PATCH] Simplify kernel pinning

---
 cookbooks/hardware/attributes/default.rb      |  1 -
 cookbooks/hardware/recipes/default.rb         | 18 +++++++++++++-----
 cookbooks/hardware/templates/default/grub.erb | 17 +----------------
 3 files changed, 14 insertions(+), 22 deletions(-)

diff --git a/cookbooks/hardware/attributes/default.rb b/cookbooks/hardware/attributes/default.rb
index 26f126abd..f80e6a528 100644
--- a/cookbooks/hardware/attributes/default.rb
+++ b/cookbooks/hardware/attributes/default.rb
@@ -1,6 +1,5 @@
 default[:hardware][:modules] = %w(loop lp rtc)
 default[:hardware][:grub][:cmdline] = %w(nomodeset)
-default[:hardware][:grub][:kernel] = :latest
 default[:hardware][:sensors] = {}
 
 if node[:dmi] && node[:dmi][:system]
diff --git a/cookbooks/hardware/recipes/default.rb b/cookbooks/hardware/recipes/default.rb
index 620c7d58b..d976e89dc 100644
--- a/cookbooks/hardware/recipes/default.rb
+++ b/cookbooks/hardware/recipes/default.rb
@@ -124,10 +124,18 @@ end
 # work (e.g: https://github.com/openstreetmap/operations/issues/45) then
 # ensure that we have the package installed. the grub template will
 # make sure that this is the default on boot.
-unless node[:hardware][:grub][:kernel] == :latest
-  package "linux-image-#{node[:hardware][:grub][:kernel]}-generic"
-  package "linux-image-extra-#{node[:hardware][:grub][:kernel]}-generic"
-  package "linux-headers-#{node[:hardware][:grub][:kernel]}-generic"
+if node[:hardware][:grub][:kernel]
+  kernel_version = node[:hardware][:grub][:kernel]
+
+  package "linux-image-#{kernel_version}-generic"
+  package "linux-image-extra-#{kernel_version}-generic"
+  package "linux-headers-#{kernel_version}-generic"
+
+  boot_device = IO.popen(["df", "/boot"]).readlines.last.split.first
+  boot_uuid = IO.popen(["blkid", "-o", "value", "-s", "UUID", boot_device]).readlines.first.chomp
+  grub_entry = "gnulinux-advanced-#{boot_uuid}>gnulinux-#{kernel_version}-advanced-#{boot_uuid}"
+else
+  grub_entry = "0"
 end
 
 if File.exist?("/etc/default/grub")
@@ -141,7 +149,7 @@ if File.exist?("/etc/default/grub")
     owner "root"
     group "root"
     mode 0644
-    variables :unit => unit, :speed => speed
+    variables :unit => unit, :speed => speed, :entry => grub_entry
     notifies :run, "execute[update-grub]"
   end
 end
diff --git a/cookbooks/hardware/templates/default/grub.erb b/cookbooks/hardware/templates/default/grub.erb
index d69a870b9..3db559191 100644
--- a/cookbooks/hardware/templates/default/grub.erb
+++ b/cookbooks/hardware/templates/default/grub.erb
@@ -2,22 +2,7 @@
 
 # Boot the first entry by default, unless we have configured
 # it to boot a specific version.
-<% if node[:hardware][:grub][:kernel] == :latest %>
-GRUB_DEFAULT="0"
-<% else
-  df = Mixlib::ShellOut.new("df /boot/grub/grub.cfg | tail -n 1 | awk '{print $1;}'")
-  df.run_command
-  df.error!
-  root=df.stdout
-
-  blkid = Mixlib::ShellOut.new("blkid -o value -s UUID #{root}")
-  blkid.run_command
-  blkid.error!
-  uuid=blkid.stdout
-
-  version="#{node[:hardware][:grub][:kernel]}-generic" %>
-GRUB_DEFAULT="gnulinux-advanced-<%= uuid %>>gnulinux-<%= version %>-advanced-<%= uuid %>"
-<% end %>
+GRUB_DEFAULT="<%= @entry %>"
 
 # Wait two seconds before booting the default entry
 GRUB_TIMEOUT="2"
-- 
2.43.2