Merge branch 'variadic-enumerators'

This adds several changes to enumerator_t and linked_list_t to improve
portability.  In particular to Apple's ARM64 iOS platform, whose calling
convention for variadic and regular functions are different.  This means
that assigning a non-variadic function to a variadic function pointer,
as we did with our enumerator_t::enumerate() implementations and several
callbacks, will result in crashes as the called function will access the
arguments differently than the caller provided them.

To avoid this issue the enumerator_t interface is now fully variadic.
A new mandatory method is added, venumerate(), that takes a va_list with
the arguments provided while enumerating.  enumerate() is replaced with
a generic implementation that prepares a va_list and calls the
enumerator's venumerate() implementation.  As this allows passing the
arguments of one enumerator to another it avoids the five pointer hack
used by enumerator_create_nested() and enumerator_create_cleaner().
To simplify the implementation of venumerate() a helper macro is provided
that assigns values from a given va_list to local variables.

The signature of the callback passed to enumerator_create_filter() has
also changed significantly.  It's now required to enumerate over the
original enumerator in the callback as this avoids the previous in/out
pointer hack. The arguments to the outer enumerator are provided in a
va_list.

Similar changes to avoid such five pointer hacks affect the signatures
of the callbacks for linked_list_t's invoke_function() and find_first()
methods.  For the latter the return type also changed from status_t to
bool, which is important as SUCCESS is defined as 0, so checks for ==
SUCCESS will now fail.

1 files changed, 30 insertions, 26 deletions

diff --git a/src/libcharon/plugins/stroke/stroke_handler.c b/src/libcharon/plugins/stroke/stroke_handler.c
index d0cc9afab..19d5a62a1 100644
--- a/src/libcharon/plugins/stroke/stroke_handler.c
+++ b/src/libcharon/plugins/stroke/stroke_handler.c
@@ -62,35 +62,39 @@ static void attributes_destroy(attributes_t *this)
 	free(this);
 }
 
-/**
- * Filter function to convert host to DNS configuration attributes
- */
-static bool attr_filter(void *lock, host_t **in,
-						configuration_attribute_type_t *type,
-						void *dummy, chunk_t *data)
+CALLBACK(attr_filter, bool,
+	void *lock, enumerator_t *orig, va_list args)
 {
-	host_t *host = *in;
+	configuration_attribute_type_t *type;
+	chunk_t *data;
+	host_t *host;
 
-	switch (host->get_family(host))
-	{
-		case AF_INET:
-			*type = INTERNAL_IP4_DNS;
-			break;
-		case AF_INET6:
-			*type = INTERNAL_IP6_DNS;
-			break;
-		default:
-			return FALSE;
-	}
-	if (host->is_anyaddr(host))
-	{
-		*data = chunk_empty;
-	}
-	else
+	VA_ARGS_VGET(args, type, data);
+
+	while (orig->enumerate(orig, &host))
 	{
-		*data = host->get_address(host);
+		switch (host->get_family(host))
+		{
+			case AF_INET:
+				*type = INTERNAL_IP4_DNS;
+				break;
+			case AF_INET6:
+				*type = INTERNAL_IP6_DNS;
+				break;
+			default:
+				continue;
+		}
+		if (host->is_anyaddr(host))
+		{
+			*data = chunk_empty;
+		}
+		else
+		{
+			*data = host->get_address(host);
+		}
+		return TRUE;
 	}
-	return TRUE;
+	return FALSE;
 }
 
 METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t*,
@@ -114,7 +118,7 @@ METHOD(attribute_handler_t, create_attribute_enumerator, enumerator_t*,
 				enumerator->destroy(enumerator);
 				return enumerator_create_filter(
 									attr->dns->create_enumerator(attr->dns),
-									(void*)attr_filter, this->lock,
+									attr_filter, this->lock,
 									(void*)this->lock->unlock);
 			}
 		}