serial: T8375: use boot activation script to define a serial console on the CLI

Required during first-boot of a system. We have images form amd64 and arm64
CPUs which also tend to have different serial interfaces (ttyS vs. ttyAMA).

The images which are installed have the correct serial setting for GRUB (ttyS0
or ttyAMA0) and the activation script will probe the Kernel command-line. If a
serial interface is defined, we will include it in the VyOS CLI configuration.

3 files changed, 87 insertions, 19 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)
diff --git a/src/conf_mode/system_console.py b/src/conf_mode/system_console.py
index 4411257e3..5d89eeba7 100755
--- a/src/conf_mode/system_console.py
+++ b/src/conf_mode/system_console.py
@@ -68,7 +68,7 @@ def verify(console):
             # and it can not be used as a serial interface
             if not os.path.isdir(by_bus_dir) or not os.path.exists(by_bus_device):
                 raise ConfigError(f'Device {device} does not support being used as tty')
-        if not is_tty(device):
+        if not is_tty(device, warning=True):
             Warning(f'Device "{device}" used for console is not a TTY!')
 
     return None
@@ -82,6 +82,7 @@ def generate(console):
                 os.unlink(os.path.join(root, basename))
 
     if not console or 'device' not in console:
+        grub_util.update_serial_console('', '', '')
         return None
 
     # replace keys in the config for ttyUSB items to use them in `apply()` later
@@ -112,14 +113,17 @@ def generate(console):
         render(config_file, 'getty/serial-getty.service.j2', device_config)
         os.symlink(config_file, getty_wants_symlink)
 
-    # GRUB
-    # For existing serial line change speed (if necessary)
-    # Only applies to ttyS0
-    if 'ttyS0' not in console['device']:
-        return None
+    # GRUB - use first defined serial console to populate Kernel console= parameter
+    device = None
+    if 'device' in console and len(console['device']) > 0:
+        # We use the first device for the Kernel console
+        console_device = next(iter(console['device']))
+        console_speed = console['device'][console_device]['speed']
 
-    speed = console['device']['ttyS0']['speed']
-    grub_util.update_console_speed(speed)
+        # get console type ("ttyS" or "ttyAMA") from console_device (e.g. "ttyS0")
+        console_type = console_device.translate(str.maketrans('', '', '0123456789'))
+        console_num = ''.join(ch for ch in console_device if ch.isdigit())
+        grub_util.update_serial_console(console_type, console_num, console_speed)
 
     return None
 
@@ -127,9 +131,9 @@ def apply(console):
     # Reset screen blanking
     call('/usr/bin/setterm -blank 0 -powersave off -powerdown 0 -term linux </dev/tty1 >/dev/tty1 2>&1')
 
-    # Service control moved to vyos.utils.serial to unify checks and prompts. 
-    # If users are connected, we want to show an informational message on completing 
-    # the process, but not halt configuration processing with an interactive prompt. 
+    # Service control moved to vyos.utils.serial to unify checks and prompts.
+    # If users are connected, we want to show an informational message on completing
+    # the process, but not halt configuration processing with an interactive prompt.
     restart_login_consoles(prompt_user=False, quiet=False)
 
     if not console:
diff --git a/src/op_mode/image_installer.py b/src/op_mode/image_installer.py
index db9647782..fb3cdda9e 100755
--- a/src/op_mode/image_installer.py
+++ b/src/op_mode/image_installer.py
@@ -42,8 +42,10 @@ from psutil import disk_partitions
 
 from vyos.base import Warning
 from vyos.configtree import ConfigTree
+from vyos.config_mgmt import unsaved_commits
 from vyos.defaults import base_dir
 from vyos.defaults import directories
+from vyos.flavor import get_image_serial_console
 from vyos.remote import download
 from vyos.system import disk
 from vyos.system import grub
@@ -69,7 +71,6 @@ from vyos.utils.process import cmd
 from vyos.utils.process import run
 from vyos.utils.process import rc_cmd
 from vyos.version import get_version_data
-from vyos.config_mgmt import unsaved_commits
 
 # define text messages
 MSG_ERR_NOT_LIVE: str = 'The system is already installed. Please use "add system image" instead.'
@@ -143,16 +144,17 @@ ISO_DOWNLOAD_PATH: str = ''
 external_download_script: str = f'{base_dir}/simple-download.py'
 external_latest_image_url_script: str = f'{base_dir}/latest-image-url.py'
 
+(flavor_sercon_type, flavor_sercon_num, flavor_sercon_speed) = get_image_serial_console()
+
 # default boot variables
 DEFAULT_BOOT_VARS: dict[str, str] = {
     'timeout': '5',
     'console_type': 'tty',
-    'console_num': '0',
-    'console_speed': '115200',
+    'console_num': flavor_sercon_num,
+    'console_speed': flavor_sercon_speed,
     'bootmode': 'normal'
 }
 
-
 def bytes_to_gb(size: int) -> float:
     """Convert Bytes to GBytes, rounded to 1 decimal number
 
@@ -767,12 +769,13 @@ def console_hint() -> str:
         path = '/dev/tty'
 
     name = Path(path).name
-    if name in ['ttyS0', 'ttyAMA0']:
+    if name in ['ttyS0']:
         return 'S'
+    elif name in ['ttyAMA0']:
+        return 'A'
     else:
         return 'K'
 
-
 def cleanup(mounts: list[str] = [], remove_items: list[str] = []) -> None:
     """Clean up after installation
 
@@ -921,10 +924,14 @@ def install_image() -> None:
         print(MSG_WARN_PASSWORD_CONFIRM)
 
     # ask for default console
+    console_dict: dict[str, str] = {'K': 'tty'}
+    if flavor_sercon_type:
+        tmp: str = flavor_sercon_type[-1] # get "S" from "ttyS" and "A" from "ttyAMA"
+        console_dict.update({tmp: flavor_sercon_type})
+
     console_type: str = ask_input(MSG_INPUT_CONSOLE_TYPE,
                                   default=console_hint(),
-                                  valid_responses=['K', 'S'])
-    console_dict: dict[str, str] = {'K': 'tty', 'S': 'ttyS'}
+                                  valid_responses=console_dict.keys())
 
     config_boot_list = [f'{DIR_CONFIG}/config.boot',
                         '/opt/vyatta/etc/config.boot.default']