dotnet: basic detection and feature extraction (#987)

scripts/show-capabilities-by-function.py

@@ -59,7 +59,9 @@ import colorama
 import capa.main
 import capa.rules
 import capa.engine
+import capa.helpers
 import capa.features
+import capa.exceptions
 import capa.render.utils as rutils
 import capa.features.freeze
 import capa.render.result_document
@@ -162,25 +164,11 @@ def main(argv=None):
             extractor = capa.main.get_extractor(
                 args.sample, args.format, args.backend, sig_paths, should_save_workspace
             )
-        except capa.main.UnsupportedFormatError:
-            logger.error("-" * 80)
-            logger.error(" Input file does not appear to be a PE file.")
-            logger.error(" ")
-            logger.error(
-                " capa currently only supports analyzing PE files (or shellcode, when using --format sc32|sc64)."
-            )
-            logger.error(" If you don't know the input file type, you can try using the `file` utility to guess it.")
-            logger.error("-" * 80)
+        except capa.exceptions.UnsupportedFormatError:
+            capa.helpers.log_unsupported_format_error()
             return -1
-        except capa.main.UnsupportedRuntimeError:
-            logger.error("-" * 80)
-            logger.error(" Unsupported runtime or Python interpreter.")
-            logger.error(" ")
-            logger.error(" capa supports running under Python 2.7 using Vivisect for binary analysis.")
-            logger.error(" It can also run within IDA Pro, using either Python 2.7 or 3.5+.")
-            logger.error(" ")
-            logger.error(" If you're seeing this message on the command line, please ensure you're running Python 2.7.")
-            logger.error("-" * 80)
+        except capa.exceptions.UnsupportedRuntimeError:
+            capa.helpers.log_unsupported_runtime_error()
             return -1
 
     meta = capa.main.collect_metadata(argv, args.sample, args.rules, extractor)