init: add run/sudo helpers

These helpers could be used to run commands as root prior to unsharing
namespaces, for example to probe the binfmt module. They aren't used
currently but are left in just in case...

Signed-off-by: Casey Connolly <kcxt@postmarketos.org>

pmb/init/run.py

@@ -0,0 +1,27 @@
+# Copyright 2025 Casey Connolly
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Wrappers for running commands prior to pmbootstrap init/unshare
+
+from pmb.init.sudo import which_sudo
+import subprocess
+import shlex
+
+
+def sudo(cmd: list[str]) -> list[str]:
+    """
+    Prefix with "sudo --" unless already running as root
+    """
+    sudo = which_sudo()
+    if not sudo:
+        return cmd
+
+    return [sudo, "--", *[shlex.quote(x) for x in cmd]]
+
+
+def run_root(cmd: list[str]) -> tuple[str, str]:
+    """
+    Run a command as root and get stdout/stderr result
+    """
+    proc = subprocess.run(sudo(cmd), capture_output=True)
+    return (proc.stdout, proc.stderr)