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, 6 insertions, 2 deletions

diff --git a/src/libcharon/plugins/medcli/medcli_config.c b/src/libcharon/plugins/medcli/medcli_config.c
index 78159c845..f34990176 100644
--- a/src/libcharon/plugins/medcli/medcli_config.c
+++ b/src/libcharon/plugins/medcli/medcli_config.c
@@ -223,10 +223,11 @@ typedef struct {
 } peer_enumerator_t;
 
 METHOD(enumerator_t, peer_enumerator_enumerate, bool,
-	peer_enumerator_t *this, peer_cfg_t **cfg)
+	peer_enumerator_t *this, va_list args)
 {
 	char *name, *local_net, *remote_net;
 	chunk_t me, other;
+	peer_cfg_t **cfg;
 	child_cfg_t *child_cfg;
 	auth_cfg_t *auth;
 	peer_cfg_create_t peer = {
@@ -249,6 +250,8 @@ METHOD(enumerator_t, peer_enumerator_enumerate, bool,
 		.mode = MODE_TUNNEL,
 	};
 
+	VA_ARGS_VGET(args, cfg);
+
 	DESTROY_IF(this->current);
 	if (!this->inner->enumerate(this->inner, &name, &me, &other,
 								&local_net, &remote_net))
@@ -295,7 +298,8 @@ METHOD(backend_t, create_peer_cfg_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_peer_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _peer_enumerator_enumerate,
 			.destroy = _peer_enumerator_destroy,
 		},
 		.ike = this->ike,