wsl2-systemd script

enter-systemd-namespace

@@ -0,0 +1,51 @@
+#!/bin/bash --norc
+
+if [ "$LOGNAME" != "root" ]; then
+    echo "You need to run $0 through sudo"
+    exit 1
+fi
+
+if [ -x /usr/sbin/daemonize ]; then
+    DAEMONIZE=/usr/sbin/daemonize
+elif [ -x /usr/bin/daemonize ]; then
+    DAEMONIZE=/usr/bin/daemonize
+else
+    echo "Cannot execute daemonize to start systemd."
+    exit 1
+fi
+
+if ! command -v /lib/systemd/systemd > /dev/null; then
+    echo "Cannot execute /lib/systemd/systemd."
+    exit 1
+fi
+
+if ! command -v /usr/bin/unshare > /dev/null; then
+    echo "Cannot execute /usr/bin/unshare."
+    exit 1
+fi
+
+SYSTEMD_EXE="/lib/systemd/systemd --unit=basic.target"
+SYSTEMD_PID="$(ps -eo pid=,args= | awk '$2" "$3=="'"$SYSTEMD_EXE"'" {print $1}')"
+if [ -z "$SYSTEMD_PID" ]; then
+    "$DAEMONIZE" /usr/bin/unshare --fork --pid --mount-proc bash -c 'export container=wsl; mount -t binfmt_misc binfmt_misc /proc/sys/fs/binfmt_misc; exec '"$SYSTEMD_EXE"
+    while [ -z "$SYSTEMD_PID" ]; do
+        echo "Sleeping for 1 second to let systemd settle"
+        sleep 1
+        SYSTEMD_PID="$(ps -eo pid=,args= | awk '$2" "$3=="'"$SYSTEMD_EXE"'" {print $1}')"
+    done
+fi
+
+USER_HOME="$(getent passwd | awk -F: '$1=="'"$SUDO_USER"'" {print $6}')"
+if [ -n "$SYSTEMD_PID" ] && [ "$SYSTEMD_PID" != "1" ]; then
+    if [ -n "$1" ] && [ "$1" != "bash --login" ] && [ "$1" != "/bin/bash --login" ]; then
+        exec /usr/bin/nsenter -t "$SYSTEMD_PID" -a \
+            /usr/bin/sudo -H -u "$SUDO_USER" \
+            /bin/bash -c 'set -a; [ -f "$HOME/.systemd-env" ] && source "$HOME/.systemd-env"; set +a; exec bash -c '"$(printf "%q" "$@")"
+    else
+        exec /usr/bin/nsenter -t "$SYSTEMD_PID" -a \
+            /bin/login -p -f "$SUDO_USER" \
+            $([ -f "$USER_HOME/.systemd-env" ] && /bin/cat "$USER_HOME/.systemd-env" | xargs printf ' %q')
+    fi
+    echo "Existential crisis"
+    exit 1
+fi