Merge feature/initrdless-detection into ubuntu/master [a=davidkrauser] [r=rcj]

MP: https://code.launchpad.net/~davidkrauser/livecd-rootfs/+git/livecd-rootfs/+merge/387862

debian/changelog

@@ -1,3 +1,9 @@
+livecd-rootfs (2.678) UNRELEASED; urgency=medium
+
+  * Add mechanism to detect initrdless boot fallback
+
+ -- David Krauser <david.krauser@canonical.com>  Wed, 22 Jul 2020 14:43:09 -0400
+
 livecd-rootfs (2.677) groovy; urgency=medium
 
   * Avoid rbind /sys for chroot snap pre-seeding (cgroups fail to unmount)

live-build/functions

@@ -962,6 +962,32 @@ replace_kernel () {
     force_boot_without_initramfs ${mountpoint}
 }
 
+track_initramfs_boot_fallback() {
+    mountpoint=$1
+    cat <<END > "${mountpoint}/etc/grub.d/01_track_initrdless_boot_fallback"
+#! /bin/sh
+# ${IMAGE_STR}
+# This will detect if we attempt to boot with an initramfs and fail.
+# In the case of a failure, initrdless_boot_fallback_triggered is set to
+# a non-zero value in the grubenv. This value can be checked after boot
+# by looking in /boot/grub/grubenv or by using the grub-editenv list command.
+set -e
+END
+    cat <<"END" >> "${mountpoint}/etc/grub.d/01_track_initrdless_boot_fallback"
+cat <<"EOF"
+if [ -n "${have_grubenv}" ]; then
+  if [ -n "${initrdfail}" ]; then
+    set initrdless_boot_fallback_triggered="${initrdfail}"
+  else
+    set initrdless_boot_fallback_triggered=0
+  fi
+  save_env initrdless_boot_fallback_triggered
+fi
+EOF
+END
+    chmod +x "${mountpoint}/etc/grub.d/01_track_initrdless_boot_fallback"
+}
+
 force_boot_without_initramfs() {
     mountpoint=$1
 

live-build/ubuntu-cpc/hooks.d/base/disk-image-uefi.binary

@@ -133,6 +133,7 @@ install_grub() {
     chroot mountpoint dpkg-query -W > binary/boot/filesystem.packages
 
     divert_grub mountpoint
+    track_initramfs_boot_fallback mountpoint
     chroot mountpoint update-grub
     replace_grub_root_with_label mountpoint
     undivert_grub mountpoint

live-build/ubuntu-cpc/hooks.d/base/disk-image.binary

@@ -119,6 +119,11 @@ if [ "${should_install_grub}" -eq 1 ]; then
         --device-map=/tmp/device.map \
         ${loop_device}
 
+    divert_grub mountpoint
+    track_initramfs_boot_fallback mountpoint
+    chroot mountpoint update-grub
+    undivert_grub mountpoint
+
     rm mountpoint/tmp/device.map
 fi