From 70123750236cc12e454189d83f0c42ae971f97b0 Mon Sep 17 00:00:00 2001
From: Michael Marineau <michael.marineau@coreos.com>
Date: Wed, 20 Jul 2016 17:48:51 -0700
Subject: [PATCH] grub: abort boot if gptprio fails

If the gptprio.next command fails to give us something to boot we
shouldn't try! In order to diagnose why the failure happened halt
immediately so the user can see the error message.
---
 build_library/grub.cfg        | 36 +++++++++++++++++++++++++++++------
 build_library/grub_install.sh |  2 +-
 2 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/build_library/grub.cfg b/build_library/grub.cfg
index 99433f23c0..79bb971e31 100644
--- a/build_library/grub.cfg
+++ b/build_library/grub.cfg
@@ -107,13 +107,37 @@ 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 $oem_id $linux_append"
 
-menuentry "CoreOS default" --id=coreos {
-    gptprio.next -d usr -u usr_uuid
-    if [ "$usr_uuid" = "7130c94a-213a-4e5a-8e26-6cce9662f132" ]; then
-       linux$suf /coreos/vmlinuz-a @@MOUNTUSR@@=PARTUUID=$usr_uuid $linux_cmdline
-    else
-       linux$suf /coreos/vmlinuz-b @@MOUNTUSR@@=PARTUUID=$usr_uuid $linux_cmdline
+# Re-implement grub_abort() since no command exposes it.
+function abort {
+    echo
+    echo "Aborted. Press enter to exit GRUB."
+    read anything
+    exit
+}
+
+# Select the kernel and usr partition to boot.
+function gptprio {
+    # TODO: device name is no longer needed, should make it optional...
+    gptprio.next -d usr_device -u usr_uuid
+    if [ $? -ne 0 -o -z "$usr_uuid" ]; then
+        echo
+        echo "Reading or updating the GPT failed!"
+        echo "Please file a bug with any messages above to CoreOS:"
+        echo " https://github.com/coreos/bugs/issues"
+        abort
     fi
+
+    set gptprio_cmdline="@@MOUNTUSR@@=PARTUUID=$usr_uuid"
+    if [ "$usr_uuid" = "7130c94a-213a-4e5a-8e26-6cce9662f132" ]; then
+        set gptprio_kernel="/coreos/vmlinuz-a"
+    else
+        set gptprio_kernel="/coreos/vmlinuz-b"
+    fi
+}
+
+menuentry "CoreOS default" --id=coreos {
+    gptprio
+    linux$suf $gptprio_kernel $gptprio_cmdline $linux_cmdline
 }
 
 menuentry "CoreOS USR-A" --id=coreos-a {
diff --git a/build_library/grub_install.sh b/build_library/grub_install.sh
index 96c92a1755..b4cbba9598 100755
--- a/build_library/grub_install.sh
+++ b/build_library/grub_install.sh
@@ -39,7 +39,7 @@ GRUB_DIR="coreos/grub/${FLAGS_target}"
 GRUB_SRC="/usr/lib/grub/${FLAGS_target}"
 
 # Modules required to boot a standard CoreOS configuration
-CORE_MODULES=( normal search test fat part_gpt search_fs_uuid gzio search_part_label terminal gptprio configfile memdisk tar echo )
+CORE_MODULES=( normal search test fat part_gpt search_fs_uuid gzio search_part_label terminal gptprio configfile memdisk tar echo read )
 
 # Name of the core image, depends on target
 CORE_NAME=