Only create default config file in interactive mode (#4218)

This fixes macOS unit tests, and makes a bit more sense.

scapy/main.py

@@ -64,27 +64,18 @@
 ]
 
 
-def _probe_config_file(*cf, default=None):
-    # type: (str, Optional[str]) -> Union[str, None]
+def _probe_config_file(*cf):
+    # type: (str) -> Union[str, None]
     path = pathlib.Path(os.path.expanduser("~"))
     if not path.exists():
         # ~ folder doesn't exist. Unsalvageable
         return None
-    cf_path = path.joinpath(*cf)
-    if not cf_path.exists():
-        if default is not None:
-            # We have a default ! set it
-            cf_path.parent.mkdir(parents=True, exist_ok=True)
-            with cf_path.open("w") as fd:
-                fd.write(default)
-            return str(cf_path.resolve())
-        return None
-    return str(cf_path.resolve())
+    return str(path.joinpath(*cf).resolve())
 
 
 def _read_config_file(cf, _globals=globals(), _locals=locals(),
-                      interactive=True):
-    # type: (str, Dict[str, Any], Dict[str, Any], bool) -> None
+                      interactive=True, default=None):
+    # type: (str, Dict[str, Any], Dict[str, Any], bool, Optional[str]) -> None
     """Read a config file: execute a python file while loading scapy, that
     may contain some pre-configured values.
 
@@ -93,11 +84,13 @@ def _read_config_file(cf, _globals=globals(), _locals=locals(),
     function. Otherwise, vars are only available from inside the scapy
     console.
 
-    params:
-    - _globals: the globals() vars
-    - _locals: the locals() vars
-    - interactive: specified whether or not errors should be printed
+    Parameters:
+
+    :param _globals: the globals() vars
+    :param _locals: the locals() vars
+    :param interactive: specified whether or not errors should be printed
     using the scapy console or raised.
+    :param default: if provided, set a default value for the config file
 
     ex, content of a config.py file:
         'conf.verb = 42\n'
@@ -107,6 +100,16 @@ def _read_config_file(cf, _globals=globals(), _locals=locals(),
         2
 
     """
+    cf_path = pathlib.Path(cf)
+    if not cf_path.exists():
+        log_loading.debug("Config file [%s] does not exist.", cf)
+        if default is None:
+            return
+        # We have a default ! set it
+        cf_path.parent.mkdir(parents=True, exist_ok=True)
+        with cf_path.open("w") as fd:
+            fd.write(default)
+        log_loading.debug("Config file [%s] created with default.", cf)
     log_loading.debug("Loading config file [%s]", cf)
     try:
         with open(cf) as cfgf:
@@ -151,8 +154,7 @@ def _validate_local(k):
 # conf.use_pcap = True
 """.strip()
 
-DEFAULT_PRESTART_FILE = _probe_config_file(".config", "scapy", "prestart.py",
-                                           default=DEFAULT_PRESTART)
+DEFAULT_PRESTART_FILE = _probe_config_file(".config", "scapy", "prestart.py")
 DEFAULT_STARTUP_FILE = _probe_config_file(".config", "scapy", "startup.py")
 
 
@@ -718,7 +720,8 @@ def interact(mydict=None, argv=None, mybanner=None, loglevel=logging.INFO):
         _read_config_file(
             PRESTART_FILE,
             interactive=True,
-            _locals=_scapy_prestart_builtins()
+            _locals=_scapy_prestart_builtins(),
+            default=DEFAULT_PRESTART,
         )
 
     SESSION = init_session(session_name, mydict=mydict, ret=True)

test/regression.uts

@@ -651,7 +651,8 @@ assert len(conf.temp_files) == 0
 import mock, sys
 from scapy.main import interact
 
-from scapy.main import DEFAULT_PRESTART_FILE
+from scapy.main import DEFAULT_PRESTART_FILE, DEFAULT_PRESTART, _read_config_file
+_read_config_file(DEFAULT_PRESTART_FILE, _locals=globals(), default=DEFAULT_PRESTART)
 # By now .config/scapy/startup.py should have been created
 with open(DEFAULT_PRESTART_FILE, "r") as fd:
     OLD_DEFAULT_PRESTART = fd.read()
@@ -691,7 +692,8 @@ interact_emulator(extra_args=["-d"])  # Extended
 import sys
 import mock
 
-from scapy.main import DEFAULT_PRESTART_FILE
+from scapy.main import DEFAULT_PRESTART_FILE, DEFAULT_PRESTART, _read_config_file
+_read_config_file(DEFAULT_PRESTART_FILE, _locals=globals(), default=DEFAULT_PRESTART)
 # By now .config/scapy/startup.py should have been created
 with open(DEFAULT_PRESTART_FILE, "w+") as fd:
     fd.write("conf.interactive_shell = 'ptpython'")
@@ -1093,6 +1095,7 @@ assert "NameError" in ret[0]
 
 cmds = """log_runtime.info(hex_bytes("446166742050756e6b"))\n"""
 ret = autorun_get_text_interactive_session(cmds)
+ret
 assert "Daft Punk" in ret[0]
 
 = Test utility TEX functions
@@ -1122,8 +1125,8 @@ conf.verb = saved_conf_verb
 
 = Test config file functions failures
 
-from scapy.main import _probe_config_file
-assert _probe_config_file("filethatdoesnotexistnorwillever.tsppajfsrdrr") is None
+from scapy.main import _read_config_file, _probe_config_file
+assert _read_config_file(_probe_config_file("filethatdoesnotexistnorwillever.tsppajfsrdrr")) is None
 
 = Test CacheInstance repr