configd: T3302: set mode correctly on open for redirect

1 files changed, 7 insertions, 3 deletions

diff --git a/src/services/vyos-configd b/src/services/vyos-configd
index 7aea77f5a..1e60e53df 100755
--- a/src/services/vyos-configd
+++ b/src/services/vyos-configd
@@ -63,6 +63,7 @@ configd_env_unset_file = os.path.join(directories['data'], 'vyos-configd-env-uns
 configd_env_file = '/etc/default/vyos-configd-env'
 
 session_out = None
+session_mode = None
 
 def key_name_from_file_name(f):
     return os.path.splitext(f)[0]
@@ -111,7 +112,7 @@ include_set = {key_name_from_file_name(f) for f in filenames if f in include}
 def run_script(script, config) -> int:
     config.set_level([])
     try:
-        with open(session_out, 'a') as f, redirect_stdout(f):
+        with open(session_out, session_mode) as f, redirect_stdout(f):
             with redirect_stderr(f):
                 c = script.get_config(config)
                 script.verify(c)
@@ -119,7 +120,7 @@ def run_script(script, config) -> int:
                 script.apply(c)
     except ConfigError as e:
         logger.critical(e)
-        with open(session_out, 'a') as f, redirect_stdout(f):
+        with open(session_out, session_mode) as f, redirect_stdout(f):
             print(f"{e}\n")
         return R_ERROR_COMMIT
     except Exception as e:
@@ -130,6 +131,7 @@ def run_script(script, config) -> int:
 
 def initialization(socket):
     global session_out
+    global session_mode
     # Reset config strings:
     active_string = ''
     session_string = ''
@@ -158,12 +160,14 @@ def initialization(socket):
     logger.debug(f"config session pid is {pid_string}")
     try:
         session_out = os.readlink(f"/proc/{pid_string}/fd/1")
+        session_mode = 'w'
     except FileNotFoundError:
         session_out = None
 
     # if not a 'live' session, for example on boot, write to file
-    if '/dev/pts' not in session_out:
+    if not session_out or '/dev/pts' not in session_out:
         session_out = script_stdout_log
+        session_mode = 'a'
 
     try:
         configsource = ConfigSourceString(running_config_text=active_string,