configquery: T8409: resolve op-mode config paths independent of edit level

op_mode_config_dict() rewrote the absolute path passed in by the caller
into one relative to VYATTA_EDIT_LEVEL. list_strip() returns an empty
list as soon as a path component mismatches, so from e.g. [edit qos
policy] the path "qos interface eth1" became the current edit level
itself and cli-shell-api dumped an unrelated subtree:

  [edit qos policy]
  vyos@vyos# run show qos shaper interface eth1
  WARNING: Specified configuration path is not valid
  QoS is not applied to eth1!

Relative lookups are unreliable even when the edit level is a proper
prefix of the path, as cli-shell-api validates the path against
VYATTA_TEMPLATE_LEVEL and rejects a relative tag node value.

Keep the absolute path and reset both level variables for the child
process instead.

1 files changed, 8 insertions, 11 deletions

diff --git a/python/vyos/configquery.py b/python/vyos/configquery.py
index 3f385d97b..8ee819f19 100644
--- a/python/vyos/configquery.py
+++ b/python/vyos/configquery.py
@@ -39,7 +39,6 @@ from vyos.xml_ref import is_tag
 from vyos.base import Warning
 from vyos.utils.backend import vyconf_backend
 from vyos.configsource import ConfigSourceVyconfSession
-from vyos.utils.list import list_strip
 
 config_file = os.path.join(directories['config'], 'config.boot')
 
@@ -183,9 +182,9 @@ def verify_mangling(key_mangling):
         raise ValueError('key_mangling must be a tuple of two strings')
 
 
-def op_mode_run(cmd):
+def op_mode_run(cmd, env=None):
     """low-level to avoid overhead"""
-    p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
+    p = subprocess.Popen(cmd, stdout=subprocess.PIPE, env=env)
     out = p.stdout.read()
     p.wait()
     return p.returncode, out.decode()
@@ -203,15 +202,13 @@ def op_mode_config_dict(
 
     command = ['/bin/cli-shell-api', '--show-active-only', 'showConfig']
 
-    edit_level = os.environ.get('VYATTA_EDIT_LEVEL', '')
-    if edit_level:
-        tmp = edit_level.split('/')
-        edit_path = [el for el in tmp if el]
-        relative_path = list_strip(path, edit_path)
-    else:
-        relative_path = path
+    # An op-mode script may be called from within a configuration session at
+    # an arbitrary edit level; cli-shell-api resolves the requested path
+    # relative to that level. Reset the level for the child process, so the
+    # absolute path passed by the caller is always used as is.
+    env = os.environ | {'VYATTA_EDIT_LEVEL': '/', 'VYATTA_TEMPLATE_LEVEL': '/'}
 
-    rc, out = op_mode_run(command + relative_path)
+    rc, out = op_mode_run(command + path, env=env)
 
     if rc == cli_shell_api_err.VYOS_EMPTY_CONFIG:
         out = ''