1 files changed, 57 insertions, 0 deletions
diff --git a/src/activation-scripts/05-serial_console.py b/src/activation-scripts/05-serial_console.py
new file mode 100755
index 000000000..93e381d17
--- /dev/null
+++ b/src/activation-scripts/05-serial_console.py
@@ -0,0 +1,57 @@
+# Copyright (C) VyOS Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+import re
+
+from typing import Optional
+from typing import Tuple
+
+from vyos.configtree import ConfigTree
+from vyos.utils.file import read_file
+from vyos.system.image import is_live_boot
+
+base = ['system', 'console', 'device']
+
+def get_kernel_serial_console() -> Tuple[Optional[str], Optional[str]]:
+    """
+    Extract the serial console device and speed setting from the kernel
+    command line.
+    """
+    device = speed = None
+    CMDLINE_CONSOLE_RE = re.compile(
+        r'(?:^|\s)console=(?P<device>tty(?:S|AMA)\d+),(?P<speed>\d+)(?=\s|$)'
+    )
+    kernel_cmdline = read_file('/proc/cmdline')
+    if m := CMDLINE_CONSOLE_RE.search(kernel_cmdline):
+        device = m.group("device") # "ttyS0"
+        speed = m.group("speed")   # Baud rate/speed, e.g. "115200"
+
+    return (device, speed)
+
+def activate(config: ConfigTree):
+    # Configure the kernel serial console only once during live boot.
+    # During installation, the user can define the console. If this is not
+    # limited to live boot, the serial interface will always be re-added during
+    # system boot, even if it was removed from config.boot.
+    if not is_live_boot():
+        return
+
+    (device, speed) = get_kernel_serial_console()
+    if device and speed:
+        # The kernel was booted with a configured serial console, but no
+        # console is configured in the CLI; align/fix the CLI configuration.
+        if not config.exists(base + [device]):
+            config.set(base + [device, 'speed'], value=speed)
+            config.set_tag(base)