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, 8 insertions, 9 deletions

diff --git a/src/libcharon/plugins/uci/uci_parser.c b/src/libcharon/plugins/uci/uci_parser.c
index 2429e9e44..e847dd393 100644
--- a/src/libcharon/plugins/uci/uci_parser.c
+++ b/src/libcharon/plugins/uci/uci_parser.c
@@ -58,11 +58,10 @@ typedef struct {
 } section_enumerator_t;
 
 METHOD(enumerator_t, section_enumerator_enumerate, bool,
-	section_enumerator_t *this, ...)
+	section_enumerator_t *this, va_list args)
 {
 	struct uci_element *element;
 	char **value;
-	va_list args;
 	int i;
 
 	if (&this->current->list == this->list)
@@ -70,8 +69,6 @@ METHOD(enumerator_t, section_enumerator_enumerate, bool,
 		return FALSE;
 	}
 
-	va_start(args, this);
-
 	value = va_arg(args, char**);
 	if (value)
 	{
@@ -96,7 +93,6 @@ METHOD(enumerator_t, section_enumerator_enumerate, bool,
 			*value = uci_to_option(element)->value;
 		}
 	}
-	va_end(args);
 
 	this->current = list_to_element(this->current->list.next);
 	return TRUE;
@@ -124,7 +120,13 @@ METHOD(uci_parser_t, create_section_enumerator, enumerator_t*,
 		i++;
 	}
 	va_end(args);
-	e = malloc(sizeof(section_enumerator_t) + sizeof(char*) * i);
+	INIT_EXTRA(e, sizeof(char*) * i,
+		.public = {
+			.enumerate = enumerator_enumerate_default,
+			.venumerate = _section_enumerator_enumerate,
+			.destroy = _section_enumerator_destroy,
+		},
+	);
 	i = 0;
 	va_start(args, this);
 	do
@@ -134,9 +136,6 @@ METHOD(uci_parser_t, create_section_enumerator, enumerator_t*,
 	while (e->keywords[i++]);
 	va_end(args);
 
-	e->public.enumerate = (void*)_section_enumerator_enumerate;
-	e->public.destroy = _section_enumerator_destroy;
-
 	/* load uci context */
 	e->ctx = uci_alloc_context();
 	if (uci_load(e->ctx, this->package, &e->package) != UCI_OK)