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.

3 files changed, 18 insertions, 14 deletions

diff --git a/src/libcharon/plugins/dhcp/dhcp_provider.c b/src/libcharon/plugins/dhcp/dhcp_provider.c
index f0681b1da..50ffbab9d 100644
--- a/src/libcharon/plugins/dhcp/dhcp_provider.c
+++ b/src/libcharon/plugins/dhcp/dhcp_provider.c
@@ -151,8 +151,7 @@ METHOD(attribute_provider_t, create_attribute_enumerator, enumerator_t*,
 	identification_t *id;
 	host_t *vip;
 
-	if (pools->find_first(pools, (linked_list_match_t)streq,
-						  NULL, "dhcp") != SUCCESS)
+	if (!pools->find_first(pools, linked_list_match_str, NULL, "dhcp"))
 	{
 		return NULL;
 	}
diff --git a/src/libcharon/plugins/dhcp/dhcp_socket.c b/src/libcharon/plugins/dhcp/dhcp_socket.c
index 807c68274..42f8f1ef9 100644
--- a/src/libcharon/plugins/dhcp/dhcp_socket.c
+++ b/src/libcharon/plugins/dhcp/dhcp_socket.c
@@ -382,8 +382,7 @@ METHOD(dhcp_socket_t, enroll, dhcp_transaction_t*,
 	while (try <= DHCP_TRIES && discover(this, transaction))
 	{
 		if (!this->condvar->timed_wait(this->condvar, this->mutex, 1000 * try) &&
-			this->request->find_first(this->request, NULL,
-									  (void**)&transaction) == SUCCESS)
+			this->request->find_first(this->request, NULL, (void**)&transaction))
 		{
 			break;
 		}
diff --git a/src/libcharon/plugins/dhcp/dhcp_transaction.c b/src/libcharon/plugins/dhcp/dhcp_transaction.c
index 3ee88a698..87711799c 100644
--- a/src/libcharon/plugins/dhcp/dhcp_transaction.c
+++ b/src/libcharon/plugins/dhcp/dhcp_transaction.c
@@ -114,16 +114,22 @@ METHOD(dhcp_transaction_t, add_attribute, void,
 	this->attributes->insert_last(this->attributes, entry);
 }
 
-/**
- * Filter function to map entries to type/data
- */
-static bool attribute_filter(void *null, attribute_entry_t **entry,
-							 configuration_attribute_type_t *type,
-							 void **dummy, chunk_t *data)
+CALLBACK(attribute_filter, bool,
+	void *null, enumerator_t *orig, va_list args)
 {
-	*type = (*entry)->type;
-	*data = (*entry)->data;
-	return TRUE;
+	configuration_attribute_type_t *type;
+	attribute_entry_t *entry;
+	chunk_t *data;
+
+	VA_ARGS_VGET(args, type, data);
+
+	if (orig->enumerate(orig, &entry))
+	{
+		*type = entry->type;
+		*data = entry->data;
+		return TRUE;
+	}
+	return FALSE;
 }
 
 METHOD(dhcp_transaction_t, create_attribute_enumerator, enumerator_t*,
@@ -131,7 +137,7 @@ METHOD(dhcp_transaction_t, create_attribute_enumerator, enumerator_t*,
 {
 	return enumerator_create_filter(
 						this->attributes->create_enumerator(this->attributes),
-						(void*)attribute_filter, NULL, NULL);
+						attribute_filter, NULL, NULL);
 }
 
 /**