Updated extractor return code to distinguish between non-existent extrators and…

Updated extractor return code to distinguish between non-existent extrators and failed extration attempts.

src/binwalk/modules/extractor.py

@@ -373,7 +373,7 @@ class Extractor(Module):
                         extract_ok = True
 
                     # Only clean up files if remove_after_execute was specified                
-                    if extract_ok and self.remove_after_execute:
+                    if extract_ok == True and self.remove_after_execute:
 
                         # Remove the original file that we extracted
                         try:
@@ -394,7 +394,7 @@ class Extractor(Module):
                                 pass
                     
                     # If the command executed OK, don't try any more rules
-                    if extract_ok:
+                    if extract_ok == True:
                         break
                     # Else, remove the extracted file if this isn't the last rule in the list.
                     # If it is the last rule, leave the file on disk for the user to examine.
@@ -527,7 +527,7 @@ class Extractor(Module):
         @cmd   - Command to execute.
         @fname - File to run command against.
 
-        Returns True on success, False on failure.
+        Returns True on success, False on failure, or None if the external extraction utility could not be found.
         '''
         tmp = None
         retval = True
@@ -549,7 +549,9 @@ class Extractor(Module):
                 cmd = cmd.replace(self.FILE_NAME_PLACEHOLDER, fname)
     
                 # Execute.
-                if subprocess.call(shlex.split(cmd), stdout=tmp, stderr=tmp) != 0:
+                if subprocess.call(shlex.split(cmd), stdout=tmp, stderr=tmp) == 0:
+                    retval = True
+                else:
                     retval = False
         except KeyboardInterrupt as e:
             raise e
@@ -559,7 +561,7 @@ class Extractor(Module):
             # annoying to see this spammed out to the console every time.
             if not hasattr(e, 'errno') or e.errno != 2:
                 sys.stderr.write("WARNING: Extractor.execute failed to run external extrator '%s': %s\n" % (str(cmd), str(e)))
-            retval = False
+            retval = None
         
         if tmp is not None:
             tmp.close()

src/binwalk/plugins/lzmamod.py

@@ -18,7 +18,7 @@ class LZMAModPlugin(binwalk.core.plugin.Plugin):
         self.original_cmd = ''
 
         # Replace the existing LZMA extraction command with our own
-		# Note that this assumes that there is *one* LZMA extraction command...
+        # Note that this assumes that there is *one* LZMA extraction command...
         rules = self.module.extractor.get_rules()
         for i in range(0, len(rules)):
             if rules[i]['regex'].match(self.SIGNATURE) and rules[i]['cmd']:
@@ -28,7 +28,10 @@ class LZMAModPlugin(binwalk.core.plugin.Plugin):
 
     def lzma_cable_extractor(self, fname):
         # Try extracting the LZMA file without modification first
-        if not self.module.extractor.execute(self.original_cmd, fname):
+        result = self.module.extractor.execute(self.original_cmd, fname)
+        
+        # If the external extractor was successul (True) or didn't exist (None), don't do anything.
+        if result not in [True, None]:
             out_name = os.path.splitext(fname)[0] + '-patched' + os.path.splitext(fname)[1]
             fp_out = BlockFile(out_name, 'w')
             # Use self.module.config.open_file here to ensure that other config settings (such as byte-swapping) are honored