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, 25 insertions, 10 deletions

diff --git a/src/libcharon/plugins/sql/sql_cred.c b/src/libcharon/plugins/sql/sql_cred.c
index 117eec921..3317de6c8 100644
--- a/src/libcharon/plugins/sql/sql_cred.c
+++ b/src/libcharon/plugins/sql/sql_cred.c
@@ -52,11 +52,14 @@ 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 blob;
 	int type;
 
+	VA_ARGS_VGET(args, key);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &type, &blob))
 	{
@@ -88,7 +91,8 @@ 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,
 		},
 	);
@@ -132,11 +136,14 @@ 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;
 	chunk_t blob;
 	int type;
 
+	VA_ARGS_VGET(args, cert);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &type, &blob))
 	{
@@ -169,7 +176,8 @@ 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,
 		},
 	);
@@ -221,12 +229,15 @@ typedef struct {
 } shared_enumerator_t;
 
 METHOD(enumerator_t, shared_enumerator_enumerate, bool,
-	   shared_enumerator_t *this, shared_key_t **shared,
-	   id_match_t *me, id_match_t *other)
+	   shared_enumerator_t *this, va_list args)
 {
+	shared_key_t **shared;
+	id_match_t *me, *other;
 	chunk_t blob;
 	int type;
 
+	VA_ARGS_VGET(args, shared, me, other);
+
 	DESTROY_IF(this->current);
 	while (this->inner->enumerate(this->inner, &type, &blob))
 	{
@@ -265,7 +276,8 @@ METHOD(credential_set_t, create_shared_enumerator, enumerator_t*,
 
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_shared_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _shared_enumerator_enumerate,
 			.destroy = _shared_enumerator_destroy,
 		},
 		.me = me,
@@ -340,9 +352,11 @@ typedef enum {
 } cdp_type_t;
 
 METHOD(enumerator_t, cdp_enumerator_enumerate, bool,
-	   cdp_enumerator_t *this, char **uri)
+	   cdp_enumerator_t *this, va_list args)
 {
-	char *text;
+	char *text, **uri;
+
+	VA_ARGS_VGET(args, uri);
 
 	free(this->current);
 	while (this->inner->enumerate(this->inner, &text))
@@ -384,7 +398,8 @@ METHOD(credential_set_t, create_cdp_enumerator, enumerator_t*,
 	}
 	INIT(e,
 		.public = {
-			.enumerate = (void*)_cdp_enumerator_enumerate,
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _cdp_enumerator_enumerate,
 			.destroy = _cdp_enumerator_destroy,
 		},
 	);