From 21b9f711a44b4c9ff5c751e8b0c1122e25f84143 Mon Sep 17 00:00:00 2001
From: Michael Marineau <michael.marineau@coreos.com>
Date: Mon, 8 Jul 2013 15:42:24 -0400
Subject: [PATCH] feat(cgpt): Statically allocate UUIDs for ROOT partitions.

Before we can switch from using device names in root= to partition table
UUIDs we need some values that will remain consistent across upgrades
since the partition table is not updated when filesystems are.
---
 build_library/cgpt.py                 | 16 +++++++++++++---
 build_library/legacy_disk_layout.json |  9 +++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/build_library/cgpt.py b/build_library/cgpt.py
index cd0d89c418..57ad46b247 100755
--- a/build_library/cgpt.py
+++ b/build_library/cgpt.py
@@ -8,6 +8,7 @@ import json
 import os
 import re
 import sys
+import uuid
 from optparse import OptionParser
 
 # First sector we can use.
@@ -35,7 +36,7 @@ def LoadPartitionConfig(filename):
   valid_keys = set(('_comment', 'metadata', 'layouts'))
   valid_layout_keys = set((
       '_comment', 'type', 'num', 'label', 'blocks', 'block_size', 'fs_blocks',
-      'fs_block_size', 'features'))
+      'fs_block_size', 'features', 'uuid'))
 
   if not os.path.exists(filename):
     raise ConfigNotFound('Partition config %s was not found!' % filename)
@@ -77,6 +78,15 @@ def LoadPartitionConfig(filename):
             raise InvalidLayout(
                 'Filesystem may not be larger than partition: %s %s: %d > %d' %
                 (layout_name, part['label'], part['fs_bytes'], part['bytes']))
+
+        if 'uuid' in part:
+          try:
+            # double check the string formatting
+            part['uuid'] = str(uuid.UUID(part['uuid']))
+          except ValueError as e:
+            raise InvalidLayout('Invalid uuid %r: %s' % (part['uuid'], e))
+        else:
+          part['uuid'] = str(uuid.uuid4())
   except KeyError as e:
     raise InvalidLayout('Layout is missing required entries: %s' % e)
 
@@ -291,9 +301,9 @@ def WriteLayoutFunction(options, sfile, func_name, image_type, config):
   # Pass 2: Write out all the cgpt add commands.
   for partition in partitions:
     if partition['type'] != 'blank':
-      sfile.write('$GPT add -i %d -b $CURR -s %s -t %s -l %s $1 && ' % (
+      sfile.write('$GPT add -i %d -b $CURR -s %s -t %s -l %s -u %s $1 && ' % (
           partition['num'], str(partition['var']), partition['type'],
-          partition['label']))
+          partition['label'], partition['uuid']))
     if partition['type'] == 'efi':
       sfile.write('$GPT boot -p -b $2 -i %d $1\n' % partition['num'])
 
diff --git a/build_library/legacy_disk_layout.json b/build_library/legacy_disk_layout.json
index 6ca9d47c69..724c93895d 100644
--- a/build_library/legacy_disk_layout.json
+++ b/build_library/legacy_disk_layout.json
@@ -21,6 +21,7 @@
       {
         "num": 3,
         "label":"ROOT-A",
+        "uuid":"7130c94a-213a-4e5a-8e26-6cce9662f132",
         "type":"coreos-rootfs",
         "blocks":"4194304",
         "fs_blocks":"262144"
@@ -28,6 +29,7 @@
       {
         "num": 4,
         "label":"ROOT-B",
+        "uuid":"e03dd35c-7c2d-4a47-b3fe-27f15780a57c",
         "type":"coreos-rootfs",
         "blocks":"4194304",
         "fs_blocks":"262144"
@@ -35,6 +37,7 @@
       {
         "num": 5,
         "label":"ROOT-C",
+        "uuid":"d82521b4-07ac-4f1c-8840-ddefedc332f3",
         "type":"coreos-rootfs",
         "blocks":"1"
       },
@@ -68,6 +71,7 @@
       {
         "num": 3,
         "label":"ROOT-A",
+        "uuid":"7130c94a-213a-4e5a-8e26-6cce9662f132",
         "type":"coreos-rootfs",
         "blocks":"2539520",
         "fs_blocks":"262144"
@@ -75,6 +79,7 @@
       {
         "num": 4,
         "label":"ROOT-B",
+        "uuid":"e03dd35c-7c2d-4a47-b3fe-27f15780a57c",
         "type":"coreos-rootfs",
         "blocks":"1"
       }
@@ -89,6 +94,7 @@
       {
         "num": 3,
         "label":"ROOT-A",
+        "uuid":"7130c94a-213a-4e5a-8e26-6cce9662f132",
         "type":"coreos-rootfs",
         "blocks":"860160",
         "fs_blocks":"102400"
@@ -96,6 +102,7 @@
       {
         "num": 4,
         "label":"ROOT-B",
+        "uuid":"e03dd35c-7c2d-4a47-b3fe-27f15780a57c",
         "type":"coreos-rootfs",
         "blocks":"1"
       },
@@ -110,6 +117,7 @@
       {
         "num": 3,
         "label":"ROOT-A",
+        "uuid":"7130c94a-213a-4e5a-8e26-6cce9662f132",
         "type":"coreos-rootfs",
         "blocks":"2097152",
         "fs_blocks":"262144"
@@ -117,6 +125,7 @@
       {
         "num": 4,
         "label":"ROOT-B",
+        "uuid":"e03dd35c-7c2d-4a47-b3fe-27f15780a57c",
         "type":"coreos-rootfs",
         "blocks":"2097152",
         "fs_blocks":"262144"