Userland: Add support for jails

This happens in two ways:
1. LibCore now has two new methods for creating Jails and attaching
   processes to a Jail.
2. We introduce 3 new utilities - lsjails, jail-create and jails-attach,
   which list jails, create jails and attach processes to a Jail,
   respectively.

1 files changed, 28 insertions, 0 deletions

diff --git a/Userland/Utilities/jail-attach.cpp b/Userland/Utilities/jail-attach.cpp
new file mode 100644
index 0000000000..ba09dafc49
--- /dev/null
+++ b/Userland/Utilities/jail-attach.cpp
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2022, Liav A. <liavalb@hotmail.co.il>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCore/ArgsParser.h>
+#include <LibCore/System.h>
+#include <LibMain/Main.h>
+#include <unistd.h>
+
+ErrorOr<int> serenity_main(Main::Arguments arguments)
+{
+    unsigned jail_index = 0;
+    Vector<StringView> command;
+    Core::ArgsParser args_parser;
+    bool preserve_env = false;
+    args_parser.set_stop_on_first_non_option(true);
+    args_parser.add_option(preserve_env, "Preserve user environment when running command", "preserve-env", 'E');
+    args_parser.add_positional_argument(jail_index, "Jail Index", "jail index");
+    args_parser.add_positional_argument(command, "Command to execute", "command");
+    args_parser.parse(arguments);
+
+    TRY(Core::System::pledge("stdio rpath exec id jail tty"));
+    TRY(Core::System::join_jail(jail_index));
+    TRY(Core::System::exec_command(command, preserve_env));
+    return 0;
+}