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, 16 insertions, 10 deletions

diff --git a/src/libcharon/plugins/attr/attr_provider.c b/src/libcharon/plugins/attr/attr_provider.c
index f4c143641..3310f79fd 100644
--- a/src/libcharon/plugins/attr/attr_provider.c
+++ b/src/libcharon/plugins/attr/attr_provider.c
@@ -75,17 +75,23 @@ typedef struct {
 	ike_version_t ike;
 } enumerator_data_t;
 
-/**
- * convert enumerator value from attribute_entry
- */
-static bool attr_enum_filter(enumerator_data_t *data, attribute_entry_t **in,
-			configuration_attribute_type_t *type, void* none, chunk_t *value)
+CALLBACK(attr_enum_filter, bool,
+	enumerator_data_t *data, enumerator_t *orig, va_list args)
 {
-	if ((*in)->ike == IKE_ANY || (*in)->ike == data->ike)
+	configuration_attribute_type_t *type;
+	attribute_entry_t *entry;
+	chunk_t *value;
+
+	VA_ARGS_VGET(args, type, value);
+
+	while (orig->enumerate(orig, &entry))
 	{
-		*type = (*in)->type;
-		*value = (*in)->value;
-		return TRUE;
+		if (entry->ike == IKE_ANY || entry->ike == data->ike)
+		{
+			*type = entry->type;
+			*value = entry->value;
+			return TRUE;
+		}
 	}
 	return FALSE;
 }
@@ -112,7 +118,7 @@ METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
 		this->lock->read_lock(this->lock);
 		return enumerator_create_filter(
 				this->attributes->create_enumerator(this->attributes),
-				(void*)attr_enum_filter, data, attr_enum_destroy);
+				attr_enum_filter, data, attr_enum_destroy);
 	}
 	return enumerator_create_empty();
 }