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, 12 insertions, 4 deletions

diff --git a/src/libcharon/plugins/medcli/medcli_creds.c b/src/libcharon/plugins/medcli/medcli_creds.c
index 677229b9f..528fc004d 100644
--- a/src/libcharon/plugins/medcli/medcli_creds.c
+++ b/src/libcharon/plugins/medcli/medcli_creds.c
@@ -50,10 +50,13 @@ typedef struct {
 } private_enumerator_t;
 
 METHOD(enumerator_t, private_enumerator_enumerate, bool,
-	private_enumerator_t *this, private_key_t **key)
+	private_enumerator_t *this, va_list args)
 {
+	private_key_t **key;
 	chunk_t chunk;
 
+	VA_ARGS_VGET(args, key);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &chunk))
 	{
@@ -92,7 +95,8 @@ METHOD(credential_set_t, create_private_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_private_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _private_enumerator_enumerate,
 			.destroy = _private_enumerator_destroy,
 		},
 	);
@@ -123,11 +127,14 @@ typedef struct {
 } cert_enumerator_t;
 
 METHOD(enumerator_t, cert_enumerator_enumerate, bool,
-	cert_enumerator_t *this, certificate_t **cert)
+	cert_enumerator_t *this, va_list args)
 {
+	certificate_t **cert;
 	public_key_t *public;
 	chunk_t chunk;
 
+	VA_ARGS_VGET(args, cert);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &chunk))
 	{
@@ -180,7 +187,8 @@ METHOD(credential_set_t, create_cert_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cert_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cert_enumerator_enumerate,
 			.destroy = _cert_enumerator_destroy,
 		},
 		.type = key,