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, 14 insertions, 7 deletions

diff --git a/src/libcharon/plugins/stroke/stroke_config.c b/src/libcharon/plugins/stroke/stroke_config.c
index d47787d72..00f74831c 100644
--- a/src/libcharon/plugins/stroke/stroke_config.c
+++ b/src/libcharon/plugins/stroke/stroke_config.c
@@ -68,13 +68,20 @@ METHOD(backend_t, create_peer_cfg_enumerator, enumerator_t*,
 									 (void*)this->mutex->unlock, this->mutex);
 }
 
-/**
- * filter function for ike configs
- */
-static bool ike_filter(void *data, peer_cfg_t **in, ike_cfg_t **out)
+CALLBACK(ike_filter, bool,
+	void *data, enumerator_t *orig, va_list args)
 {
-	*out = (*in)->get_ike_cfg(*in);
-	return TRUE;
+	peer_cfg_t *cfg;
+	ike_cfg_t **out;
+
+	VA_ARGS_VGET(args, out);
+
+	if (orig->enumerate(orig, &cfg))
+	{
+		*out = cfg->get_ike_cfg(cfg);
+		return TRUE;
+	}
+	return FALSE;
 }
 
 METHOD(backend_t, create_ike_cfg_enumerator, enumerator_t*,
@@ -82,7 +89,7 @@ METHOD(backend_t, create_ike_cfg_enumerator, enumerator_t*,
 {
 	this->mutex->lock(this->mutex);
 	return enumerator_create_filter(this->list->create_enumerator(this->list),
-									(void*)ike_filter, this->mutex,
+									ike_filter, this->mutex,
 									(void*)this->mutex->unlock);
 }