From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Thu, 13 Feb 2020 12:27:18 +0000 (+0100)
Subject: scanner: use list_is_first() from scanner_pop_indesc()
X-Git-Tag: v0.9.4~60
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f391fdd8e0fbaf3749819cfa0cd9b478f3630a7d;p=thirdparty%2Fnftables.git

scanner: use list_is_first() from scanner_pop_indesc()

!list_empty() always stands true since the list is never empty
when calling scanner_pop_indesc().

Check for list_is_first() which actually tells us this is the
initial input file, hence, state->indesc is set to NULL.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/include/list.h b/include/list.h
index 75d29212..9c4da817 100644
--- a/include/list.h
+++ b/include/list.h
@@ -33,6 +33,17 @@ static inline void init_list_head(struct list_head *list)
 	list->prev = list;
 }
 
+/**
+ * list_is_first -- tests whether @list is the first entry in list @head
+ * @list: the entry to test
+ * @head: the head of the list
+ */
+static inline int list_is_first(const struct list_head *list,
+				const struct list_head *head)
+{
+	return list->prev == head;
+}
+
 /*
  * Insert a new entry between two known consecutive entries.
  *
diff --git a/src/scanner.l b/src/scanner.l
index ed29833b..3932883b 100644
--- a/src/scanner.l
+++ b/src/scanner.l
@@ -678,7 +678,7 @@ static void scanner_push_indesc(struct parser_state *state,
 
 static void scanner_pop_indesc(struct parser_state *state)
 {
-	if (!list_empty(&state->indesc_list)) {
+	if (!list_is_first(&state->indesc->list, &state->indesc_list)) {
 		state->indesc = list_entry(state->indesc->list.prev,
 					   struct input_descriptor, list);
 	} else {