From 1906a44413cf8130e3ce99dad43a7e4711c2c53b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabiano=20Fid=C3=AAncio?= <ffidencio@nvidia.com>
Date: Sun, 10 May 2026 19:04:06 +0200
Subject: [PATCH] image-builder: support building extension images without
 /sbin/init check
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Extension images (e.g. the CoCo guest components extension) are not full root
filesystems -- they contain only the binaries and configuration that
get bind-mounted into the real rootfs at boot.  The existing
check_rootfs() validation requires /sbin/init and systemd, which are
not present in extension images.

Add a SKIP_ROOTFS_CHECK environment variable that, when set to "yes",
bypasses the check_rootfs() call.  Forward the variable into the
container environment when using the Docker-based build path so it
works in both direct and containerised invocations.

Signed-off-by: Fabiano Fidêncio <ffidencio@nvidia.com>
Assisted-by: Cursor <cursoragent@cursor.com>
---
 tools/osbuilder/image-builder/image_builder.sh | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/tools/osbuilder/image-builder/image_builder.sh b/tools/osbuilder/image-builder/image_builder.sh
index 5d98c98aff..490edde19c 100755
--- a/tools/osbuilder/image-builder/image_builder.sh
+++ b/tools/osbuilder/image-builder/image_builder.sh
@@ -179,6 +179,7 @@ build_with_container() {
 		   --env NSDAX_BIN="${nsdax_bin}" \
 		   --env SKIP_DAX_HEADER="${SKIP_DAX_HEADER}" \
 		   --env MEASURED_ROOTFS="${MEASURED_ROOTFS}" \
+		   --env SKIP_ROOTFS_CHECK="${SKIP_ROOTFS_CHECK:-no}" \
 		   --env SELINUX="${SELINUX}" \
 		   --env DEBUG="${DEBUG}" \
 		   --env ARCH="${ARCH}" \
@@ -456,6 +457,12 @@ setup_selinux() {
 }
 
 setup_systemd() {
+		# Extension content images (e.g. the gpu extension) carry no /etc and are not
+		# bootable systemd rootfses, so there is nothing to set up here.
+		if [[ ! -d "${mount_dir}/etc" ]]; then
+			info "No /etc in rootfs; skipping systemd machine-id setup"
+			return 0
+		fi
 		info "Creating empty machine-id to allow systemd to bind-mount it"
 		touch "${mount_dir}/etc/machine-id"
 }
@@ -715,8 +722,10 @@ main() {
 		exit $?
 	fi
 
-	if ! check_rootfs "${rootfs}" ; then
-		die "Invalid rootfs"
+	if [[ "${SKIP_ROOTFS_CHECK:-no}" != "yes" ]]; then
+		if ! check_rootfs "${rootfs}" ; then
+			die "Invalid rootfs"
+		fi
 	fi
 
 	local skip_dax="${SKIP_DAX_HEADER:-no}"