system: op-mode: T3334: allow delayed getty restart when configuring serial ports

* Created op-mode command "restart serial console"
* Relocated service control to vyos.utils.serial helpers, used by conf- and
  op-mode serial console handling
  * Checking for logged-in serial sessions that may be affected by getty reconfig
  * Warning the user when changes are committed and serial sessions are active,
    otherwise restart services as normal. No prompts issued during commit,
    all config gen/commit steps still occur except for the service restarts
    (everything remains consistent)
  * To apply committed changes, user will need to run "restart serial console"
    to complete the process or reboot the whole router
  * Added additional flags and target filtering for generic use of helpers.

1 files changed, 38 insertions, 0 deletions

diff --git a/src/op_mode/serial.py b/src/op_mode/serial.py
new file mode 100644
index 000000000..a5864872b
--- /dev/null
+++ b/src/op_mode/serial.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2024 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import sys, typing
+
+import vyos.opmode
+from vyos.utils.serial import restart_login_consoles as _restart_login_consoles
+
+def restart_console(device_name: typing.Optional[str]):
+    # Service control moved to vyos.utils.serial to unify checks and prompts. 
+    # If users are connected, we want to show an informational message and a prompt
+    # to continue, verifying that the user acknowledges possible interruptions. 
+    if device_name:
+        _restart_login_consoles(prompt_user=True, quiet=False, devices=[device_name])
+    else:
+        _restart_login_consoles(prompt_user=True, quiet=False)
+
+if __name__ == '__main__':
+    try:
+        res = vyos.opmode.run(sys.modules[__name__])
+        if res:
+            print(res)
+    except (ValueError, vyos.opmode.Error) as e:
+        print(e)
+        sys.exit(1)