commands: add a shell command

This command spawns an interactive shell on your host but inside the
user and mount namespaces that pmbootstrap set up. It is mostly useful
for debugging issues with permissions, etc.

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

pmb/commands/__init__.py

@@ -17,6 +17,7 @@ from .pkgrel_bump import PkgrelBump
 from .pkgver_bump import PkgverBump
 from .pull import Pull
 from .kconfig import KConfigCheck, KConfigEdit, KConfigMigrate
+from .shell import Shell
 
 """New way to model pmbootstrap subcommands that can be invoked without PmbArgs."""
 
@@ -89,6 +90,8 @@ def run_command(args: PmbArgs) -> None:
             command = PkgverBump(args.packages)
         case "pull":
             command = Pull()
+        case "shell":
+            command = Shell()
         case "kconfig":
             match args.action_kconfig:
                 case "check":

pmb/commands/shell.py

@@ -0,0 +1,14 @@
+# Copyright 2024 Caleb Connolly
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from __future__ import annotations
+from pmb import commands
+import pmb.helpers.run
+
+
+class Shell(commands.Command):
+    def __init__(self) -> None:
+        pass
+
+    def run(self) -> None:
+        pmb.helpers.run.user(["sh", "-i"], output="tui", check=False)

pmb/parse/arguments.py

@@ -1008,6 +1008,10 @@ def get_parser() -> argparse.ArgumentParser:
     log.add_argument("-n", "--lines", type=int, default=60, help="count of initial output lines")
     log.add_argument("-c", "--clear", help="clear the log", action="store_true", dest="clear_log")
 
+    # Actions: shell
+    # Spawn a shell after unshare()
+    sub.add_parser("shell", help="Spawn a shell after unsharing namespaces (DEBUGGING)")
+
     # Action: zap
     zap = sub.add_parser("zap", help="safely delete chroot folders")
     zap.add_argument(