Show appropriate error message when an external variable is redefined with a…

Show appropriate error message when an external variable is redefined with a different type. See issue #12.

yara-python.c

@@ -901,6 +901,56 @@ static size_t flo_write(
 }
 
 
+PyObject* handle_error(
+    int error,
+    char* extra)
+{
+  switch(error)
+  {
+    case ERROR_COULD_NOT_ATTACH_TO_PROCESS:
+      return PyErr_Format(
+        YaraError,
+        "access denied");
+    case ERROR_INSUFICIENT_MEMORY:
+      return PyErr_NoMemory();
+    case ERROR_COULD_NOT_OPEN_FILE:
+      return PyErr_Format(
+          YaraError,
+          "could not open file \"%s\"",
+          extra);
+    case ERROR_COULD_NOT_MAP_FILE:
+      return PyErr_Format(
+          YaraError,
+          "could not map file \"%s\" into memory",
+          extra);
+    case ERROR_INVALID_FILE:
+      return PyErr_Format(
+          YaraError,
+          "invalid rules file \"%s\"",
+          extra);
+    case ERROR_CORRUPT_FILE:
+      return PyErr_Format(
+          YaraError,
+          "corrupt rules file \"%s\"",
+          extra);
+    case ERROR_SCAN_TIMEOUT:
+      return PyErr_Format(
+          YaraTimeoutError,
+          "scanning timed out");
+    case ERROR_INVALID_EXTERNAL_VARIABLE_TYPE:
+      return PyErr_Format(
+          YaraError,
+          "external variable \"%s\" was already defined with a different type",
+          extra);
+    default:
+      return PyErr_Format(
+          YaraError,
+          "internal error: %d",
+          error);
+  }
+}
+
+
 int process_compile_externals(
     PyObject* externals,
     YR_COMPILER* compiler)
@@ -910,6 +960,7 @@ int process_compile_externals(
   Py_ssize_t pos = 0;
 
   char* identifier = NULL;
+  int result;
 
   while (PyDict_Next(externals, &pos, &key, &value))
   {
@@ -917,7 +968,7 @@ int process_compile_externals(
 
     if (PyBool_Check(value))
     {
-      yr_compiler_define_boolean_variable(
+      result = yr_compiler_define_boolean_variable(
           compiler,
           identifier,
           PyObject_IsTrue(value));
@@ -928,32 +979,42 @@ int process_compile_externals(
     else if (PyLong_Check(value) || PyInt_Check(value))
 #endif
     {
-      yr_compiler_define_integer_variable(
+      result = yr_compiler_define_integer_variable(
           compiler,
           identifier,
           PyLong_AsLong(value));
     }
     else if (PyFloat_Check(value))
     {
-      yr_compiler_define_float_variable(
+      result = yr_compiler_define_float_variable(
           compiler,
           identifier,
           PyFloat_AsDouble(value));
     }
     else if (PY_STRING_CHECK(value))
     {
-      yr_compiler_define_string_variable(
+      result = yr_compiler_define_string_variable(
           compiler,
           identifier,
           PY_STRING_TO_C(value));
     }
     else
     {
-      return FALSE;
+      PyErr_Format(
+          PyExc_TypeError,
+          "external values must be of type integer, float, boolean or string");
+
+      return ERROR_INVALID_ARGUMENT;
+    }
+
+    if (result != ERROR_SUCCESS)
+    {
+      handle_error(result, identifier);
+      return result;
     }
   }
 
-  return TRUE;
+  return ERROR_SUCCESS;
 }
 
 
@@ -966,6 +1027,7 @@ int process_match_externals(
   Py_ssize_t pos = 0;
 
   char* identifier = NULL;
+  int result;
 
   while (PyDict_Next(externals, &pos, &key, &value))
   {
@@ -973,7 +1035,7 @@ int process_match_externals(
 
     if (PyBool_Check(value))
     {
-      yr_rules_define_boolean_variable(
+      result = yr_rules_define_boolean_variable(
           rules,
           identifier,
           PyObject_IsTrue(value));
@@ -984,77 +1046,42 @@ int process_match_externals(
     else if (PyLong_Check(value) || PyInt_Check(value))
 #endif
     {
-      yr_rules_define_integer_variable(
+      result = yr_rules_define_integer_variable(
           rules,
           identifier,
           PyLong_AsLong(value));
     }
     else if (PyFloat_Check(value))
     {
-      yr_rules_define_float_variable(
+      result = yr_rules_define_float_variable(
           rules,
           identifier,
           PyFloat_AsDouble(value));
     }
     else if (PY_STRING_CHECK(value))
     {
-      yr_rules_define_string_variable(
+      result = yr_rules_define_string_variable(
           rules,
           identifier,
           PY_STRING_TO_C(value));
     }
     else
     {
-      return FALSE;
-    }
-  }
-
-  return TRUE;
-}
+      PyErr_Format(
+          PyExc_TypeError,
+          "external values must be of type integer, float, boolean or string");
 
+      return ERROR_INVALID_ARGUMENT;
+    }
 
-PyObject* handle_error(
-    int error,
-    char* extra)
-{
-  switch(error)
+    if (result != ERROR_SUCCESS)
     {
-    case ERROR_COULD_NOT_ATTACH_TO_PROCESS:
-      return PyErr_Format(
-        YaraError,
-        "access denied");
-    case ERROR_INSUFICIENT_MEMORY:
-      return PyErr_NoMemory();
-    case ERROR_COULD_NOT_OPEN_FILE:
-      return PyErr_Format(
-          YaraError,
-          "could not open file \"%s\"",
-          extra);
-    case ERROR_COULD_NOT_MAP_FILE:
-      return PyErr_Format(
-          YaraError,
-          "could not map file \"%s\" into memory",
-          extra);
-    case ERROR_INVALID_FILE:
-      return PyErr_Format(
-          YaraError,
-          "invalid rules file \"%s\"",
-          extra);
-    case ERROR_CORRUPT_FILE:
-      return PyErr_Format(
-          YaraError,
-          "corrupt rules file \"%s\"",
-          extra);
-    case ERROR_SCAN_TIMEOUT:
-      return PyErr_Format(
-          YaraTimeoutError,
-          "scanning timed out");
-    default:
-      return PyErr_Format(
-          YaraError,
-          "internal error: %d",
-          error);
+      handle_error(result, identifier);
+      return result;
+    }
   }
+
+  return ERROR_SUCCESS;
 }
 
 
@@ -1378,14 +1405,11 @@ static PyObject* Rules_match(
     {
       if (PyDict_Check(externals))
       {
-        if (!process_match_externals(externals, object->rules))
+        if (process_match_externals(externals, object->rules) != ERROR_SUCCESS)
         {
           // Restore original externals provided during compiling.
           process_match_externals(object->externals, object->rules);
-
-          return PyErr_Format(
-              PyExc_TypeError,
-              "external values must be of type integer, float, boolean or string");
+          return NULL;
         }
       }
       else
@@ -1453,21 +1477,24 @@ static PyObject* Rules_match(
 
     // Restore original externals provided during compiling.
     if (object->externals != NULL)
-      process_match_externals(object->externals, object->rules);
+    {
+      if (process_match_externals(
+            object->externals, object->rules) != ERROR_SUCCESS)
+      {
+        Py_DECREF(callback_data.matches);
+        return NULL;
+      }
+    }
 
     if (error != ERROR_SUCCESS)
     {
       Py_DECREF(callback_data.matches);
 
-      if (error == ERROR_CALLBACK_ERROR)
-      {
-        return NULL;
-      }
-      else
+      if (error != ERROR_CALLBACK_ERROR)
       {
         handle_error(error, filepath);
 
-#ifdef PROFILING_ENABLED
+        #ifdef PROFILING_ENABLED
         PyObject* exception = PyErr_Occurred();
 
         if (exception != NULL && error == ERROR_SCAN_TIMEOUT)
@@ -1477,12 +1504,12 @@ static PyObject* Rules_match(
               "profiling_info",
               Rules_profiling_info(self, NULL));
         }
-#endif
+        #endif
+      }
 
       return NULL;
     }
   }
-  }
 
   return callback_data.matches;
 }
@@ -1759,12 +1786,10 @@ static PyObject* yara_compile(
     {
       if (PyDict_Check(externals))
       {
-        if (!process_compile_externals(externals, compiler))
+        if (process_compile_externals(externals, compiler) != ERROR_SUCCESS)
         {
           yr_compiler_destroy(compiler);
-          return PyErr_Format(
-              PyExc_TypeError,
-              "external values must be of type integer, float, boolean or string");
+          return NULL;
         }
       }
       else