From 9e1c23f3f44d2751076e770f43f7a6db05d49652 Mon Sep 17 00:00:00 2001
From: Benjamin Gilbert <benjamin.gilbert@coreos.com>
Date: Wed, 1 Mar 2017 16:10:21 -0800
Subject: [PATCH] grub: Set coreos.first_boot based on existence of file in ESP

Detect first boot based on the existence of a coreos/first_boot file
in the EFI partition, and set "coreos.first_boot=detected" command line
argument when found. We use "detected" rather than "1" so the initramfs
knows that it should mount the ESP and delete the file. This lets us
defer clearing the first-boot flag until Ignition has run successfully,
without having to change the disk GUID after filesystems are mounted.

Continue detecting the first-boot disk GUID and adding the command-line
argument to randomize it, since we still want unique disk GUIDs
regardless of Ignition.
---
 build_library/generate_grub_hashes.py |  2 +-
 build_library/grub.cfg                | 15 ++++++++++-----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/build_library/generate_grub_hashes.py b/build_library/generate_grub_hashes.py
index 8bc82a3dfe..750bb607b8 100755
--- a/build_library/generate_grub_hashes.py
+++ b/build_library/generate_grub_hashes.py
@@ -47,7 +47,7 @@ commands = [{"value": '\[.*\]', "description": "CoreOS Grub configuration %s" %
             {"value": 'insmod all_video', "description": "CoreOS Grub configuration %s" % version},
             {"value": 'linux /coreos/vmlinuz-[ab] rootflags=rw mount.usrflags=ro consoleblank=0 root=LABEL=ROOT (console=\S+)? (coreos.autologin=\S+)?', "description": "CoreOS Grub configuration %s" % version},
             {"value": 'menuentry CoreOS \S+ --id=coreos\S* {', "description": "CoreOS Grub configuration %s" % version},
-            {"value": 'search --no-floppy --set first_boot --disk-uuid 00000000-0000-0000-0000-000000000001', "description": "CoreOS Grub configuration %s" % version},
+            {"value": 'search --no-floppy --set randomize_disk_guid --disk-uuid 00000000-0000-0000-0000-000000000001', "description": "CoreOS Grub configuration %s" % version},
             {"value": 'search --no-floppy --set oem --part-label OEM --hint hd0,gpt1', "description": "CoreOS Grub configuration %s" % version},
             {"value": 'set .+', "description": "CoreOS Grub configuration %s" % version},
             {"value": 'setparams CoreOS default', "description": "CoreOS Grub configuration %s" % version},
diff --git a/build_library/grub.cfg b/build_library/grub.cfg
index 38fd617600..0b0bea432d 100644
--- a/build_library/grub.cfg
+++ b/build_library/grub.cfg
@@ -15,6 +15,7 @@ set timeout=1
 set linux_root="root=LABEL=ROOT"
 set linux_console=""
 set first_boot=""
+set randomize_disk_guid=""
 set oem_id=""
 
 # Anything else the OEM adds should use this variable.
@@ -65,11 +66,15 @@ if [ "$secure_boot" = "0" ]; then
 fi
 
 # Determine if this is a first boot.
-search --no-floppy --set first_boot \
+if [ -f "($root)/coreos/first_boot" ]; then
+    set first_boot="coreos.first_boot=detected"
+fi
+
+# Determine if the disk GUID needs to be randomized.
+search --no-floppy --set randomize_disk_guid \
        --disk-uuid 00000000-0000-0000-0000-000000000001
-if [ -n "$first_boot" ]; then
-    # Note we explicitly request the disk-guid randomization, first_boot only triggers ignition.
-    set first_boot="coreos.first_boot=1 coreos.randomize_disk_guid=00000000-0000-0000-0000-000000000001"
+if [ -n "$randomize_disk_guid" ]; then
+    set randomize_disk_guid="coreos.randomize_disk_guid=00000000-0000-0000-0000-000000000001"
 fi
 
 set oem=""
@@ -111,7 +116,7 @@ if [ "$grub_platform" = efi ]; then
 fi
 
 # Assemble the options applicable to all the kernels below
-set linux_cmdline="rootflags=rw mount.usrflags=ro consoleblank=0 $linux_root $linux_console $first_boot $extra_options $oem $linux_append"
+set linux_cmdline="rootflags=rw mount.usrflags=ro consoleblank=0 $linux_root $linux_console $first_boot $randomize_disk_guid $extra_options $oem $linux_append"
 
 # Re-implement grub_abort() since no command exposes it.
 function abort {