tools/toolbox: Add toolbox-sysext-install.sh script

The new command will take an extension directory set up
with `meson-build --sysext` inside a toolbox, and turn
it into a merged system extension on the host.

Namely it will
 1. copy the extension directory from the container to the host
 2. set up the extension-release file expected by systemd-sysext
 3. compile gsettings schemas if necessary (using the merged
    schemas directory)
 4. install the extension to either runtime or system
 5. merge the extension

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3498>

diff --git a/tools/toolbox/toolbox-sysext-install.sh b/tools/toolbox/toolbox-sysext-install.sh
new file mode 100755 (executable)
index 0000000..0ff3b65
--- /dev/null
+++ b/tools/toolbox/toolbox-sysext-install.sh
@@ -0,0 +1,143 @@
+#!/usr/bin/bash
+
+set -eu
+
+DEFAULT_TOOLBOX=gnome-shell-devel
+CONFIG_FILE=${XDG_CONFIG_HOME:-$HOME/.config}/gnome-shell-toolbox-tools.conf
+
+usage() {
+  cat <<-EOF
+       Usage: $(basename $0) [OPTION…]
+
+       Extract and install a systemd-sysext extension from a toolbox
+
+       Options:
+         -t, --toolbox=TOOLBOX   Use TOOLBOX instead of the default "$DEFAULT_TOOLBOX"
+
+         --persistent            Install extension under /var/lib/extensions/ to persist after reboots
+
+         -h, --help              Display this help
+
+       EOF
+}
+
+die() {
+  echo "$@" >&2
+  exit 1
+}
+
+init_sysext() {
+  rm -rf $HOME_SYSEXT_DIR
+  mkdir -p $HOME_SYSEXT_DIR
+  podman cp $TOOLBOX:/var/lib/extensions/$TOOLBOX/. $HOME_SYSEXT_DIR
+
+  local ext_dir=$HOME_SYSEXT_DIR/usr/lib/extension-release.d
+  mkdir -p $ext_dir
+  podman cp $TOOLBOX:/etc/os-release $ext_dir/extension-release.$TOOLBOX
+}
+
+runtime_install_command() {
+  local dest=$(dirname $RUN_SYSEXT_DIR)
+
+  echo -n "mkdir -p $dest && "
+  echo -n "ln -sf $HOME_SYSEXT_DIR $dest && "
+  echo -n "rm -fr $VAR_SYSEXT_DIR"
+}
+
+system_install_command() {
+  local dest=$(dirname $VAR_SYSEXT_DIR)
+  local attr=mode
+
+  selinuxenabled 2>/dev/null && attr="$attr,context"
+
+  echo -n "mkdir -p $dest && "
+  echo -n "cp -r --preserve=$attr $HOME_SYSEXT_DIR $dest && "
+  echo -n "rm -fr $RUN_SYSEXT_DIR"
+}
+
+install_command() {
+  if [[ ${PERSISTENT:-0} ]]; then
+    system_install_command
+  else
+    runtime_install_command
+  fi
+}
+
+sysext_merge_command() {
+  echo -n systemd-sysext refresh
+}
+
+compile_schemas_command() {
+  local schemadir=usr/share/glib-2.0/schemas
+  if [ -d $HOME_SYSEXT_DIR/$schemadir ]
+  then
+    echo -n "$(runtime_install_command) && "
+    echo -n "$(sysext_merge_command) && "
+    echo -n "glib-compile-schemas --targetdir $HOME_SYSEXT_DIR/$schemadir /$schemadir 2>/dev/null && "
+    echo -n "chown $(id -un):$(id -gn) $HOME_SYSEXT_DIR/$schemadir/gschemas.compiled"
+  else
+    echo -n :
+  fi
+}
+
+relabel_command() {
+  local setfiles=$(which setfiles 2>/dev/null)
+  if [ -x "$setfiles" ]
+  then
+    local spec=/etc/selinux/targeted/contexts/files/file_contexts
+    echo -n "$setfiles -F -r $HOME_SYSEXT_DIR $spec $HOME_SYSEXT_DIR/usr"
+  else
+    echo -n :
+  fi
+}
+
+# load defaults
+. $CONFIG_FILE
+TOOLBOX=$DEFAULT_TOOLBOX
+
+TEMP=$(getopt \
+  --name $(basename $0) \
+  --options 't:h' \
+  --longoptions 'toolbox:' \
+  --longoptions 'persistent' \
+  --longoptions 'help' \
+  -- "$@") || die "Run $(basename $0) --help to see available options"
+
+eval set -- "$TEMP"
+unset TEMP
+
+while true; do
+  case $1 in
+    -t|--toolbox)
+      TOOLBOX=$2
+      shift 2
+    ;;
+
+    --persistent)
+      PERSISTENT=1
+      shift
+    ;;
+
+    -h|--help)
+      usage
+      exit 0
+    ;;
+
+    --)
+      shift
+      break
+    ;;
+  esac
+done
+
+HOME_SYSEXT_DIR=$HOME/.local/lib/toolbox-extensions/$TOOLBOX
+RUN_SYSEXT_DIR=/run/extensions/$TOOLBOX
+VAR_SYSEXT_DIR=/var/lib/extensions/$TOOLBOX
+
+init_sysext
+
+sudo sh -c "
+  $(compile_schemas_command) &&
+  $(relabel_command) &&
+  $(install_command) &&
+  $(sysext_merge_command)"