libiptc: avoid strict-aliasing warnings

libiptc: avoid strict-aliasing warnings

In file included from libiptc/libip4tc.c:117:0:
libiptc/libiptc.c: In function ‘__iptcc_p_del_policy’:
libiptc/libiptc.c:826:4: warning: dereferencing type-punned pointer will break
strict-aliasing rules
libiptc/libiptc.c: In function ‘iptc_get_target’:
libiptc/libiptc.c:1650:4: warning: dereferencing type-punned pointer will break
strict-aliasing rules
libiptc/libip4tc.c: In function ‘dump_entry’:
libiptc/libip4tc.c:157:3: warning: dereferencing type-punned pointer will break
strict-aliasing rules
  CC     libiptc/libip6tc.lo
In file included from libiptc/libip6tc.c:112:0:
libiptc/libiptc.c: In function ‘__iptcc_p_del_policy’:
libiptc/libiptc.c:826:4: warning: dereferencing type-punned pointer will break
strict-aliasing rules
libiptc/libiptc.c: In function ‘ip6tc_get_target’:
libiptc/libiptc.c:1650:4: warning: dereferencing type-punned pointer will break
strict-aliasing rules
libiptc/libip6tc.c: In function ‘dump_entry’:
libiptc/libip6tc.c:188:3: warning: dereferencing type-punned pointer will break
strict-aliasing rules

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

Rebased for collectd/src/owniptc: Alan Pevec <apevec@gmail.com>
Signed-off-by: Florian Forster <octo@huhu.verplant.org>

src/owniptc/libip4tc.c

@@ -173,7 +173,8 @@ dump_entry(STRUCT_ENTRY *e, const TC_HANDLE_T handle)
 	t = GET_TARGET(e);
 	printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
 	if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) {
-		int pos = *(int *)t->data;
+		const unsigned char *data = t->data;
+		int pos = *(const int *)data;
 		if (pos < 0)
 			printf("verdict=%s\n",
 			       pos == -NF_ACCEPT-1 ? "NF_ACCEPT"

src/owniptc/libip6tc.c

@@ -204,7 +204,8 @@ dump_entry(struct ip6t_entry *e, const ip6tc_handle_t handle)
 	t = ip6t_get_target(e);
 	printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
 	if (strcmp(t->u.user.name, IP6T_STANDARD_TARGET) == 0) {
-		int pos = *(int *)t->data;
+		const unsigned char *data = t->data;
+		int pos = *(const int *)data;
 		if (pos < 0)
 			printf("verdict=%s\n",
 			       pos == -NF_ACCEPT-1 ? "NF_ACCEPT"

src/owniptc/libiptc.c

@@ -744,14 +744,16 @@ static void iptcc_delete_rule(struct rule_head *r)
  * to be called from specific places within the parser */
 static int __iptcc_p_del_policy(TC_HANDLE_T h, unsigned int num)
 {
+	const unsigned char *data;
+
 	if (h->chain_iterator_cur) {
 		/* policy rule is last rule */
 		struct rule_head *pr = (struct rule_head *)
 			h->chain_iterator_cur->rules.prev;
 
 		/* save verdict */
-		h->chain_iterator_cur->verdict = 
-			*(int *)GET_TARGET(pr->entry)->data;
+		data = GET_TARGET(pr->entry)->data;
+		h->chain_iterator_cur->verdict = *(const int *)data;
 
 		/* save counter and counter_map information */
 		h->chain_iterator_cur->counter_map.maptype = 
@@ -1563,6 +1565,7 @@ const char *TC_GET_TARGET(const STRUCT_ENTRY *ce,
 {
 	STRUCT_ENTRY *e = (STRUCT_ENTRY *)ce;
 	struct rule_head *r = container_of(e, struct rule_head, entry[0]);
+	const unsigned char *data;
 
 	iptc_fn = TC_GET_TARGET;
 
@@ -1576,7 +1579,8 @@ const char *TC_GET_TARGET(const STRUCT_ENTRY *ce,
 			return r->jump->name;
 			break;
 		case IPTCC_R_STANDARD:
-			spos = *(int *)GET_TARGET(e)->data;
+			data = GET_TARGET(e)->data;
+			spos = *(const int *)data;
 			DEBUGP("r=%p, spos=%d'\n", r, spos);
 			return standard_target_map(spos);
 			break;