1 files changed, 316 insertions, 0 deletions
diff --git a/python/vyos/system/compat.py b/python/vyos/system/compat.py
new file mode 100644
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+++ b/python/vyos/system/compat.py
@@ -0,0 +1,316 @@
+# Copyright 2023 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 compile, MULTILINE, DOTALL
+from functools import wraps
+from copy import deepcopy
+from typing import Union
+
+from vyos.system import disk, grub, image, SYSTEM_CFG_VER
+from vyos.template import render
+
+TMPL_GRUB_COMPAT: str = 'grub/grub_compat.j2'
+
+# define regexes and variables
+REGEX_VERSION = r'^menuentry "[^\n]*{\n[^}]*\s+linux /boot/(?P<version>\S+)/[^}]*}'
+REGEX_MENUENTRY = r'^menuentry "[^\n]*{\n[^}]*\s+linux /boot/(?P<version>\S+)/vmlinuz (?P<options>[^\n]+)\n[^}]*}'
+REGEX_CONSOLE = r'^.*console=(?P<console_type>[^\s\d]+)(?P<console_num>[\d]+).*$'
+REGEX_SANIT_CONSOLE = r'\ ?console=[^\s\d]+[\d]+(,\d+)?\ ?'
+REGEX_SANIT_INIT = r'\ ?init=\S*\ ?'
+REGEX_SANIT_QUIET = r'\ ?quiet\ ?'
+PW_RESET_OPTION = 'init=/opt/vyatta/sbin/standalone_root_pw_reset'
+
+
+class DowngradingImageTools(Exception):
+    """Raised when attempting to add an image with an earlier version
+    of image-tools than the current system, as indicated by the value
+    of SYSTEM_CFG_VER or absence thereof."""
+    pass
+
+
+def mode():
+    if grub.get_cfg_ver() >= SYSTEM_CFG_VER:
+        return False
+
+    return True
+
+
+def find_versions(menu_entries: list) -> list:
+    """Find unique VyOS versions from menu entries
+
+    Args:
+        menu_entries (list): a list with menu entries
+
+    Returns:
+        list: List of installed versions
+    """
+    versions = []
+    for vyos_ver in menu_entries:
+        versions.append(vyos_ver.get('version'))
+    # remove duplicates
+    versions = list(set(versions))
+    return versions
+
+
+def filter_unparsed(grub_path: str) -> str:
+    """Find currently installed VyOS version
+
+    Args:
+        grub_path (str): a path to the grub.cfg file
+
+    Returns:
+        str: unparsed grub.cfg items
+    """
+    config_text = Path(grub_path).read_text()
+    regex_filter = compile(REGEX_VERSION, MULTILINE | DOTALL)
+    filtered = regex_filter.sub('', config_text)
+    regex_filter = compile(grub.REGEX_GRUB_VARS, MULTILINE)
+    filtered = regex_filter.sub('', filtered)
+    regex_filter = compile(grub.REGEX_GRUB_MODULES, MULTILINE)
+    filtered = regex_filter.sub('', filtered)
+    # strip extra new lines
+    filtered = filtered.strip()
+    return filtered
+
+
+def get_search_root(unparsed: str) -> str:
+    unparsed_lines = unparsed.splitlines()
+    search_root = next((x for x in unparsed_lines if 'search' in x), '')
+    return search_root
+
+
+def sanitize_boot_opts(boot_opts: str) -> str:
+    """Sanitize boot options from console and init
+
+    Args:
+        boot_opts (str): boot options
+
+    Returns:
+        str: sanitized boot options
+    """
+    regex_filter = compile(REGEX_SANIT_CONSOLE)
+    boot_opts = regex_filter.sub('', boot_opts)
+    regex_filter = compile(REGEX_SANIT_INIT)
+    boot_opts = regex_filter.sub('', boot_opts)
+    # legacy tools add 'quiet' on add system image; this is not desired
+    regex_filter = compile(REGEX_SANIT_QUIET)
+    boot_opts = regex_filter.sub(' ', boot_opts)
+
+    return boot_opts
+
+
+def parse_entry(entry: tuple) -> dict:
+    """Parse GRUB menuentry
+
+    Args:
+        entry (tuple): tuple of (version, options)
+
+    Returns:
+        dict: dictionary with parsed options
+    """
+    # save version to dict
+    entry_dict = {'version': entry[0]}
+    # detect boot mode type
+    if PW_RESET_OPTION in entry[1]:
+        entry_dict['bootmode'] = 'pw_reset'
+    else:
+        entry_dict['bootmode'] = 'normal'
+    # find console type and number
+    regex_filter = compile(REGEX_CONSOLE)
+    entry_dict.update(regex_filter.match(entry[1]).groupdict())
+    entry_dict['boot_opts'] = sanitize_boot_opts(entry[1])
+
+    return entry_dict
+
+
+def parse_menuentries(grub_path: str) -> list:
+    """Parse all GRUB menuentries
+
+    Args:
+        grub_path (str): a path to GRUB config file
+
+    Returns:
+        list: list with menu items (each item is a dict)
+    """
+    menuentries = []
+    # read configuration file
+    config_text = Path(grub_path).read_text()
+    # parse menuentries to tuples (version, options)
+    regex_filter = compile(REGEX_MENUENTRY, MULTILINE)
+    filter_results = regex_filter.findall(config_text)
+    # parse each entry
+    for entry in filter_results:
+        menuentries.append(parse_entry(entry))
+
+    return menuentries
+
+
+def prune_vyos_versions(root_dir: str = '') -> None:
+    """Delete vyos-versions files of registered images subsequently deleted
+    or renamed by legacy image-tools
+
+    Args:
+        root_dir (str): an optional path to the root directory
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    for version in grub.version_list():
+        if not Path(f'{root_dir}/boot/{version}').is_dir():
+            grub.version_del(version)
+
+
+def update_cfg_ver(root_dir:str = '') -> int:
+    """Get minumum version of image-tools across all installed images
+
+    Args:
+        root_dir (str): an optional path to the root directory
+
+    Returns:
+        int: minimum version of image-tools
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    prune_vyos_versions(root_dir)
+
+    images_details = image.get_images_details()
+    cfg_version = min(d['tools_version'] for d in images_details)
+
+    return cfg_version
+
+
+def get_default(menu_entries: list, root_dir: str = '') -> Union[int, None]:
+    """Translate default version to menuentry index
+
+    Args:
+        menu_entries (list): list of dicts of installed version boot data
+        root_dir (str): an optional path to the root directory
+
+    Returns:
+        int: index of default version in menu_entries or None
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    grub_cfg_main = f'{root_dir}/{grub.GRUB_CFG_MAIN}'
+
+    image_name = image.get_default_image()
+
+    sublist = list(filter(lambda x: x.get('version') == image_name,
+                        menu_entries))
+    if sublist:
+        return menu_entries.index(sublist[0])
+
+    return None
+
+
+def update_version_list(root_dir: str = '') -> list[dict]:
+    """Update list of dicts of installed version boot data
+
+    Args:
+        root_dir (str): an optional path to the root directory
+
+    Returns:
+        list: list of dicts of installed version boot data
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    grub_cfg_main = f'{root_dir}/{grub.GRUB_CFG_MAIN}'
+
+    # get list of versions in menuentries
+    menu_entries = parse_menuentries(grub_cfg_main)
+    menu_versions = find_versions(menu_entries)
+
+    # get list of versions added/removed by image-tools
+    current_versions = grub.version_list(root_dir)
+
+    remove = list(set(menu_versions) - set(current_versions))
+    for ver in remove:
+        menu_entries = list(filter(lambda x: x.get('version') != ver,
+                                   menu_entries))
+
+    add = list(set(current_versions) - set(menu_versions))
+    for ver in add:
+        last = menu_entries[0].get('version')
+        new = deepcopy(list(filter(lambda x: x.get('version') == last,
+                                   menu_entries)))
+        for e in new:
+            boot_opts = e.get('boot_opts').replace(last, ver)
+            e.update({'version': ver, 'boot_opts': boot_opts})
+
+        menu_entries = new + menu_entries
+
+    return menu_entries
+
+
+def grub_cfg_fields(root_dir: str = '') -> dict:
+    """Gather fields for rendering grub.cfg
+
+    Args:
+        root_dir (str): an optional path to the root directory
+
+    Returns:
+        dict: dictionary for rendering TMPL_GRUB_COMPAT
+    """
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    grub_cfg_main = f'{root_dir}/{grub.GRUB_CFG_MAIN}'
+
+    fields = {'default': 0, 'timeout': 5}
+    # 'default' and 'timeout' from legacy grub.cfg
+    fields |= grub.vars_read(grub_cfg_main)
+
+    fields['tools_version'] = SYSTEM_CFG_VER
+    menu_entries = update_version_list(root_dir)
+    fields['versions'] = menu_entries
+
+    default = get_default(menu_entries, root_dir)
+    if default is not None:
+        fields['default'] = default
+
+    modules = grub.modules_read(grub_cfg_main)
+    fields['modules'] = modules
+
+    unparsed = filter_unparsed(grub_cfg_main).splitlines()
+    search_root = next((x for x in unparsed if 'search' in x), '')
+    fields['search_root'] = search_root
+
+    return fields
+
+
+def render_grub_cfg(root_dir: str = '') -> None:
+    """Render grub.cfg for legacy compatibility"""
+    if not root_dir:
+        root_dir = disk.find_persistence()
+
+    grub_cfg_main = f'{root_dir}/{grub.GRUB_CFG_MAIN}'
+
+    fields = grub_cfg_fields(root_dir)
+    render(grub_cfg_main, TMPL_GRUB_COMPAT, fields)
+
+
+def grub_cfg_update(func):
+    """Decorator to update grub.cfg after function call"""
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        ret = func(*args, **kwargs)
+        if mode():
+            render_grub_cfg()
+        return ret
+    return wrapper