image: T4516: Added system image tools

This commit adds the whole set of system image tools written from the scratch in
Python that allows performing all the operations on images:

* check information
* perform installation and deletion
* versions management

Also, it contains a new service that will update the GRUB menu and keep tracking
its version in the future.

WARNING: The commit contains non-reversible changes. Because of boot menu
changes, it will not be possible to manage images from older VyOS versions after
an update.

(cherry picked from commit 8f94262e8fa2477700c50303ea6e2c6ddad72adb)

1 files changed, 336 insertions, 0 deletions

diff --git a/python/vyos/system/grub.py b/python/vyos/system/grub.py
new file mode 100644
index 000000000..11c214675
--- /dev/null
+++ b/python/vyos/system/grub.py
@@ -0,0 +1,336 @@
+# Copyright 2022 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# 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/>.
+
+from pathlib import Path
+from re import MULTILINE, compile as re_compile
+from typing import Union
+from uuid import uuid5, NAMESPACE_URL, UUID
+
+from vyos.template import render
+from vyos.util import run, cmd
+from vyos.system import disk
+
+# Define variables
+GRUB_DIR_MAIN: str = '/boot/grub'
+GRUB_DIR_VYOS: str = f'{GRUB_DIR_MAIN}/grub.cfg.d'
+CFG_VYOS_HEADER: str = f'{GRUB_DIR_VYOS}/00-vyos-header.cfg'
+CFG_VYOS_MODULES: str = f'{GRUB_DIR_VYOS}/10-vyos-modules-autoload.cfg'
+CFG_VYOS_VARS: str = f'{GRUB_DIR_VYOS}/20-vyos-defaults-autoload.cfg'
+CFG_VYOS_COMMON: str = f'{GRUB_DIR_VYOS}/25-vyos-common-autoload.cfg'
+CFG_VYOS_PLATFORM: str = f'{GRUB_DIR_VYOS}/30-vyos-platform-autoload.cfg'
+CFG_VYOS_MENU: str = f'{GRUB_DIR_VYOS}/40-vyos-menu-autoload.cfg'
+CFG_VYOS_OPTIONS: str = f'{GRUB_DIR_VYOS}/50-vyos-options.cfg'
+GRUB_DIR_VYOS_VERS: str = f'{GRUB_DIR_VYOS}/vyos-versions'
+
+TMPL_VYOS_VERSION: str = 'grub/grub_vyos_version.j2'
+TMPL_GRUB_VARS: str = 'grub/grub_vars.j2'
+TMPL_GRUB_MAIN: str = 'grub/grub_main.j2'
+TMPL_GRUB_MENU: str = 'grub/grub_menu.j2'
+TMPL_GRUB_MODULES: str = 'grub/grub_modules.j2'
+TMPL_GRUB_OPTS: str = 'grub/grub_options.j2'
+TMPL_GRUB_COMMON: str = 'grub/grub_common.j2'
+
+# prepare regexes
+REGEX_GRUB_VARS: str = r'^set (?P<variable_name>.+)=[\'"]?(?P<variable_value>.*)(?<![\'"])[\'"]?$'
+REGEX_GRUB_MODULES: str = r'^insmod (?P<module_name>.+)$'
+REGEX_KERNEL_CMDLINE: str = r'^BOOT_IMAGE=/(?P<boot_type>boot|live)/((?P<image_version>.+)/)?vmlinuz.*$'
+
+
+def install(drive_path: str, boot_dir: str, efi_dir: str) -> None:
+    """Install GRUB for both BIOS and EFI modes (hybrid boot)
+
+    Args:
+        drive_path (str): path to a drive where GRUB must be installed
+        boot_dir (str): a path to '/boot' directory
+        efi_dir (str): a path to '/boot/efi' directory
+    """
+    commands: list[str] = [
+        f'grub-install --no-floppy --target=i386-pc --boot-directory={boot_dir} \
+            {drive_path} --force',
+        f'grub-install --no-floppy --recheck --target=x86_64-efi \
+            --force-extra-removable --boot-directory={boot_dir} \
+            --efi-directory={efi_dir} --bootloader-id="VyOS" \
+            --no-uefi-secure-boot'
+    ]
+    for command in commands:
+        run(command)
+
+
+def gen_version_uuid(version_name: str) -> str:
+    """Generate unique ID from version name
+
+    Use UUID5 / NAMESPACE_URL with prefix `uuid5-`
+
+    Args:
+        version_name (str): version name
+
+    Returns:
+        str: generated unique ID
+    """
+    ver_uuid: UUID = uuid5(NAMESPACE_URL, version_name)
+    ver_id: str = f'uuid5-{ver_uuid}'
+    return ver_id
+
+
+def version_add(version_name: str,
+                root_dir: str = '',
+                boot_opts: str = '') -> None:
+    """Add a new VyOS version to GRUB loader configuration
+
+    Args:
+        vyos_version (str): VyOS version name
+        root_dir (str): an optional path to the root directory.
+        Defaults to empty.
+        boot_opts (str): an optional boot options for Linux kernel.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+    version_config: str = f'{root_dir}/{GRUB_DIR_VYOS_VERS}/{version_name}.cfg'
+    render(
+        version_config, TMPL_VYOS_VERSION, {
+            'version_name': version_name,
+            'version_uuid': gen_version_uuid(version_name),
+            'boot_opts': boot_opts
+        })
+
+
+def version_del(vyos_version: str, root_dir: str = '') -> None:
+    """Delete a VyOS version from GRUB loader configuration
+
+    Args:
+        vyos_version (str): VyOS version name
+        root_dir (str): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+    version_config: str = f'{root_dir}/{GRUB_DIR_VYOS_VERS}/{vyos_version}.cfg'
+    Path(version_config).unlink(missing_ok=True)
+
+
+def version_list(root_dir: str = '') -> list[str]:
+    """Generate a list with installed VyOS versions
+
+    Args:
+        root_dir (str): an optional path to the root directory.
+        Defaults to empty.
+
+    Returns:
+        list: A list with versions names
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+    versions_files = Path(f'{root_dir}/{GRUB_DIR_VYOS_VERS}').glob('*.cfg')
+    versions_list: list[str] = []
+    for file in versions_files:
+        versions_list.append(file.stem)
+    return versions_list
+
+
+def read_env(env_file: str = '') -> dict[str, str]:
+    """Read GRUB environment
+
+    Args:
+        env_file (str, optional): a path to grub environment file.
+        Defaults to empty.
+
+    Returns:
+        dict: dictionary with GRUB environment
+    """
+    if not env_file:
+        root_dir: str = disk.find_persistence()
+        env_file = f'{root_dir}/{GRUB_DIR_MAIN}/grubenv'
+
+    env_content: str = cmd(f'grub-editenv {env_file} list').splitlines()
+    regex_filter = re_compile(r'^(?P<variable_name>.*)=(?P<variable_value>.*)$')
+    env_dict: dict[str, str] = {}
+    for env_item in env_content:
+        search_result = regex_filter.fullmatch(env_item)
+        if search_result:
+            search_result_dict: dict[str, str] = search_result.groupdict()
+            variable_name: str = search_result_dict.get('variable_name', '')
+            variable_value: str = search_result_dict.get('variable_value', '')
+            if variable_name and variable_value:
+                env_dict.update({variable_name: variable_value})
+    return env_dict
+
+
+def get_cfg_ver(root_dir: str = '') -> int:
+    """Get current version of GRUB configuration
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+
+    Returns:
+        int: a configuration version
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    cfg_ver: Union[str, None] = vars_read(f'{root_dir}/{CFG_VYOS_HEADER}').get(
+        'VYOS_CFG_VER')
+    if cfg_ver:
+        cfg_ver_int: int = int(cfg_ver)
+    else:
+        cfg_ver_int: int = 0
+    return cfg_ver_int
+
+
+def write_cfg_ver(cfg_ver: int, root_dir: str = '') -> None:
+    """Write version number of GRUB configuration
+
+    Args:
+        cfg_ver (int): a version number to write
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+
+    Returns:
+        int: a configuration version
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    vars_file: str = f'{root_dir}/{CFG_VYOS_HEADER}'
+    vars_current: dict[str, str] = vars_read(vars_file)
+    vars_current['VYOS_CFG_VER'] = str(cfg_ver)
+    vars_write(vars_file, vars_current)
+
+
+def vars_read(grub_cfg: str) -> dict[str, str]:
+    """Read variables from a GRUB configuration file
+
+    Args:
+        grub_cfg (str): a path to the GRUB config file
+
+    Returns:
+        dict: a dictionary with variables and values
+    """
+    vars_dict: dict[str, str] = {}
+    regex_filter = re_compile(REGEX_GRUB_VARS)
+    try:
+        config_text: list[str] = Path(grub_cfg).read_text().splitlines()
+    except FileNotFoundError:
+        return vars_dict
+    for line in config_text:
+        search_result = regex_filter.fullmatch(line)
+        if search_result:
+            search_dict = search_result.groupdict()
+            variable_name: str = search_dict.get('variable_name', '')
+            variable_value: str = search_dict.get('variable_value', '')
+            if variable_name and variable_value:
+                vars_dict.update({variable_name: variable_value})
+    return vars_dict
+
+
+def modules_read(grub_cfg: str) -> list[str]:
+    """Read modules list from a GRUB configuration file
+
+    Args:
+        grub_cfg (str): a path to the GRUB config file
+
+    Returns:
+        list: a list with modules to load
+    """
+    mods_list: list[str] = []
+    regex_filter = re_compile(REGEX_GRUB_MODULES, MULTILINE)
+    try:
+        config_text = Path(grub_cfg).read_text()
+    except FileNotFoundError:
+        return mods_list
+    mods_list = regex_filter.findall(config_text)
+
+    return mods_list
+
+
+def modules_write(grub_cfg: str, mods_list: list[str]) -> None:
+    """Write modules list to a GRUB configuration file (overwrite everything)
+
+    Args:
+        grub_cfg (str): a path to GRUB configuration file
+        mods_list (list): a list with modules to load
+    """
+    render(grub_cfg, TMPL_GRUB_MODULES, {'mods_list': mods_list})
+
+
+def vars_write(grub_cfg: str, grub_vars: dict[str, str]) -> None:
+    """Write variables to a GRUB configuration file (overwrite everything)
+
+    Args:
+        grub_cfg (str): a path to GRUB configuration file
+        grub_vars (dict): a dictionary with new variables
+    """
+    render(grub_cfg, TMPL_GRUB_VARS, {'vars': grub_vars})
+
+
+def set_default(version_name: str, root_dir: str = '') -> None:
+    """Set version as default boot entry
+
+    Args:
+        version_name (str): versio name
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    vars_file = f'{root_dir}/{CFG_VYOS_VARS}'
+    vars_current = vars_read(vars_file)
+    vars_current['default'] = gen_version_uuid(version_name)
+    vars_write(vars_file, vars_current)
+
+
+def common_write(root_dir: str = '') -> None:
+    """Write common GRUB configuration file (overwrite everything)
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+    common_config = f'{root_dir}/{CFG_VYOS_COMMON}'
+    render(common_config, TMPL_GRUB_COMMON, {})
+
+
+def create_structure(root_dir: str = '') -> None:
+    """Create GRUB directories structure
+
+    Args:
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to ''.
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    Path(f'{root_dir}/GRUB_DIR_VYOS_VERS').mkdir(parents=True, exist_ok=True)
+
+
+def set_console_type(console_type: str, root_dir: str = '') -> None:
+    """Write default console type to GRUB configuration
+
+    Args:
+        console_type (str): a default console type
+        root_dir (str, optional): an optional path to the root directory.
+        Defaults to empty.
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    vars_file: str = f'{root_dir}/{CFG_VYOS_VARS}'
+    vars_current: dict[str, str] = vars_read(vars_file)
+    vars_current['console_type'] = str(console_type)
+    vars_write(vars_file, vars_current)