use livefs-editor to make customized isos

a while ago I rewrote inject-subiquity-snap in python, generalized it
and put it at https://github.com/mwhudson/livefs-editor.  TBH, it's
always been better than the shell version but now there's a reason to
switch to it: the impish live server ISO use layers, which the current
shell scripts do not support and livefs-editor now does.

.gitignore

@@ -66,6 +66,7 @@ venv
 # top level dependencies fetched from git, ignore top level only.
 /probert/
 /curtin/
+/livefs-editor/
 
 # installer isos
 *.iso

scripts/inject-subiquity-snap.sh

@@ -2,31 +2,33 @@
 
 set -eux
 
-cmds=
+LIVEFS_EDITOR="${LIVEFS_EDITOR-$(readlink -f "$(dirname $(dirname ${0}))/livefs-editor")}"
-interactive=no
+[ -d $LIVEFS_EDITOR ] || git clone https://github.com/mwhudson/livefs-editor $LIVEFS_EDITOR
-edit_filesystem=no
+
-source_installer=old_iso/casper/installer.squashfs
+LIVEFS_EDITOR=$(readlink -f $LIVEFS_EDITOR)
-source_filesystem=
+
 # Path on disk to a custom snapd (e.g. one that trusts the test keys)
 snapd_pkg=
 store_url=
 tracking=stable
+
+LIVEFS_OPTS=
+
+add_livefs_opts () {
+    LIVEFS_OPTS="${LIVEFS_OPTS+$LIVEFS_OPTS }$@"
+}
+
 while getopts ":ifc:s:n:p:u:t:" opt; do
     case "${opt}" in
         i)
-            interactive=yes
+            add_livefs_opts --shell
             ;;
         c)
-            cmds="${OPTARG}"
+            add_livefs_opts --shell "${OPTARG}"
             ;;
-        f)
+        f|s|n)
-            edit_filesystem=yes
+            echo "switch to livefs-editor directly please" >2
-            ;;
+            exit 1
-        s)
-            source_installer="$(readlink -f "${OPTARG}")"
-            ;;
-        n)
-            source_filesystem="$(readlink -f "${OPTARG}")"
             ;;
         p)
             snapd_pkg="$(readlink -f "${OPTARG}")"
@@ -50,147 +52,32 @@ shift $((OPTIND-1))
 OLD_ISO="$(readlink -f "${1}")"
 SUBIQUITY_SNAP_PATH="$(readlink -f "${2}")"
 SUBIQUITY_SNAP="$(basename $SUBIQUITY_SNAP_PATH)"
-SUBIQUITY_ASSERTION="${SUBIQUITY_SNAP_PATH%.snap}.assert"
-if [ ! -f "$SUBIQUITY_ASSERTION" ]; then
-    SUBIQUITY_ASSERTION=
-fi
 NEW_ISO="$(readlink -f "${3}")"
 
 tmpdir="$(mktemp -d)"
 cd "${tmpdir}"
 
-_MOUNTS=()
-
-do_mount_existing () {
-    local mountpoint="${!#}"
-    mount "$@"
-    _MOUNTS=("${mountpoint}" "${_MOUNTS[@]+"${_MOUNTS[@]}"}")
-}
-
-do_mount () {
-    local mountpoint="${!#}"
-    mkdir "${mountpoint}"
-    do_mount_existing "$@"
-}
-
 cleanup () {
-    for m in "${_MOUNTS[@]+"${_MOUNTS[@]}"}"; do
-        umount "${m}"
-    done
     rm -rf "${tmpdir}"
 }
 
 trap cleanup EXIT
 
-add_overlay() {
-    local lower="$1"
-    local mountpoint="$2"
-    local work="$(mktemp -dp "${tmpdir}")"
-    if [ -n "${3-}" ]; then
-        local upper="${3}"
-    else
-        local upper="$(mktemp -dp "${tmpdir}")"
-    fi
-    chmod go+rx "${work}" "${upper}"
-    do_mount -t overlay overlay -o lowerdir="${lower}",upperdir="${upper}",workdir="${work}" "${mountpoint}"
-}
-
-do_mount -t iso9660 -o loop,ro "${OLD_ISO}" old_iso
-unsquashfs -d new_installer "${source_installer}"
-do_mount -t squashfs ${source_filesystem:-old_iso/casper/filesystem.squashfs} old_filesystem
-add_overlay old_filesystem tree new_installer
-do_mount_existing dev-live -t devtmpfs "tree/dev"
-do_mount_existing devpts-live -t devpts "tree/dev/pts"
-do_mount_existing proc-live -t proc "tree/proc"
-do_mount_existing sysfs-live -t sysfs "tree/sys"
-do_mount_existing securityfs-live -t securityfs "tree/sys/kernel/security"
-
-
-python3 -c '
-import os, sys, yaml
-with open("tree/var/lib/snapd/seed/seed.yaml") as fp:
-     old_seed = yaml.safe_load(fp)
-new_snaps = []
-
-subiquity_snap = {
-    "name": "subiquity",
-    "classic": True,
-    "file": sys.argv[1],
-    "channel": sys.argv[3],
-    }
-
-if sys.argv[2] == "":
-    subiquity_snap["unasserted"] = True
-
-for snap in old_seed["snaps"]:
-    if snap["name"] == "subiquity":
-        new_snaps.append(subiquity_snap)
-    else:
-        new_snaps.append(snap)
-
-with open("tree/var/lib/snapd/seed/seed.yaml", "w") as fp:
-     yaml.dump({"snaps": new_snaps}, fp)
-' "$SUBIQUITY_SNAP" "$SUBIQUITY_ASSERTION" "$tracking"
-
-rm -f tree/var/lib/snapd/seed/assertions/subiquity*.assert
-rm -f tree/var/lib/snapd/seed/snaps/subiquity*.snap
-cp "${SUBIQUITY_SNAP_PATH}" tree/var/lib/snapd/seed/snaps/
-if [ -n "${SUBIQUITY_ASSERTION}" ]; then
-    cp "${SUBIQUITY_ASSERTION}" tree/var/lib/snapd/seed/assertions/
-fi
-
 if [ -n "$store_url" ]; then
-    STORE_CONFIG=tree/etc/systemd/system/snapd.service.d/store.conf
+    cat > "store.conf" <<EOF
-    mkdir -p "$(dirname $STORE_CONFIG)"
-    cat > "$STORE_CONFIG" <<EOF
 [Service]
 Environment=SNAPD_DEBUG=1 SNAPD_DEBUG_HTTP=7 SNAPPY_TESTING=1
 Environment=SNAPPY_FORCE_API_URL=$store_url
 EOF
+    add_livefs_opts --setup-rootfs --shell 'mkdir -p rootfs/etc/systemd/system/snapd.service.d/' \
+                    --cp store.conf rootfs/etc/systemd/system/snapd.service.d/store.conf
 fi
 
 if [ -n "$snapd_pkg" ]; then
-    cp "$snapd_pkg" tree/
+    add_livefs_opts --setup-rootfs \
-    chroot tree dpkg -i $(basename "$snapd_pkg")
+                    --cp "$snapd_pkg" rootfs \
-    rm tree/$(basename "$snapd_pkg")
+                    --shell "chroot rootfs dpkg -i $(basename "$snapd_pkg")"
+                    --shell "rm rootfs/$(basename "$snapd_pkg")"
 fi
 
-add_overlay old_iso new_iso
+PYTHONPATH=$LIVEFS_EDITOR python3 -m livefs_edit $OLD_ISO $NEW_ISO --inject-snap $SUBIQUITY_SNAP_PATH $tracking $LIVEFS_OPTS
-
-if [ "$edit_filesystem" = "yes" ]; then
-    do_mount -t squashfs ${source_filesystem:-old_iso/casper/filesystem.squashfs} old_filesystem
-    add_overlay old_filesystem new_filesystem
-fi
-
-
-if [ -n "$cmds" ]; then
-    bash -c "$cmds"
-fi
-if [ "$interactive" = "yes" ]; then
-    bash
-fi
-
-/usr/lib/snapd/snap-preseed --reset $(realpath tree)
-/usr/lib/snapd/snap-preseed $(realpath tree)
-chroot tree apparmor_parser --skip-read-cache --write-cache --skip-kernel-load --verbose  -j `nproc` /etc/apparmor.d
-
-if [ "$edit_filesystem" = "yes" ]; then
-    rm new_iso/casper/filesystem.squashfs
-    mksquashfs new_filesystem new_iso/casper/filesystem.squashfs
-elif [ -n "${source_filesystem}" ]; then
-    rm new_iso/casper/filesystem.squashfs
-    cp "${source_filesystem}" new_iso/casper/filesystem.squashfs
-fi
-
-rm new_iso/casper/installer.squashfs new_iso/casper/installer.squashfs.gpg
-mksquashfs new_installer new_iso/casper/installer.squashfs
-
-(
-    cd new_iso
-    sed -i'' '/\.\/casper\/installer.squashfs/d' md5sum.txt
-    md5sum ./casper/installer.squashfs >> md5sum.txt
-)
-
-opts="$(xorriso -indev ${OLD_ISO} -report_el_torito as_mkisofs)"
-eval set -- ${opts}
-xorriso -as mkisofs "$@" -o ${NEW_ISO} -V Ubuntu\ custom new_iso

scripts/make-edge-iso.sh

@@ -4,19 +4,10 @@ set -eux
 
 # make-edge-iso.sh $old_iso $new_iso
 
-INJECT_SNAP=$(readlink -f "$(dirname ${0})/inject-subiquity-snap.sh")
+LIVEFS_EDITOR="${LIVEFS_EDITOR-$(readlink -f "$(dirname $(dirname ${0}))/livefs-editor")}"
+[ -d $LIVEFS_EDITOR ] || git clone https://github.com/mwhudson/livefs-editor $LIVEFS_EDITOR
 
 OLD_ISO="$(readlink -f "${1}")"
 NEW_ISO="$(readlink -f "${2}")"
 
-tmpdir="$(mktemp -d)"
+PYTHONPATH=$LIVEFS_EDITOR python3 -m livefs_edit $OLD_ISO $NEW_ISO --add-snap-from-store subiquity edge
-cd "${tmpdir}"
-
-cleanup () {
-    rm -rf "${tmpdir}"
-}
-
-trap cleanup EXIT
-
-snap download --channel edge subiquity
-$INJECT_SNAP $OLD_ISO subiquity_*.snap $NEW_ISO