bpf: btf: Add tests for the btf uapi changes

This patch does the followings:
1. Modify libbpf and test_btf to reflect the uapi changes in btf
2. Add test for the btf_header changes
3. Add tests for array->index_type
4. Add err_str check to the tests
5. Fix a 4 bytes hole in "struct test #1" by swapping "m" and "n"

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/lib/bpf/bpf.c

@@ -89,8 +89,8 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
 	       min(name_len, BPF_OBJ_NAME_LEN - 1));
 	attr.numa_node = create_attr->numa_node;
 	attr.btf_fd = create_attr->btf_fd;
-	attr.btf_key_id = create_attr->btf_key_id;
-	attr.btf_value_id = create_attr->btf_value_id;
+	attr.btf_key_type_id = create_attr->btf_key_type_id;
+	attr.btf_value_type_id = create_attr->btf_value_type_id;
 	attr.map_ifindex = create_attr->map_ifindex;
 
 	return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));

tools/lib/bpf/bpf.h

@@ -36,8 +36,8 @@ struct bpf_create_map_attr {
 	__u32 max_entries;
 	__u32 numa_node;
 	__u32 btf_fd;
-	__u32 btf_key_id;
-	__u32 btf_value_id;
+	__u32 btf_key_type_id;
+	__u32 btf_value_type_id;
 	__u32 map_ifindex;
 };
 

tools/lib/bpf/btf.c

@@ -35,9 +35,8 @@ struct btf {
 
 static const char *btf_name_by_offset(const struct btf *btf, uint32_t offset)
 {
-	if (!BTF_STR_TBL_ELF_ID(offset) &&
-	    BTF_STR_OFFSET(offset) < btf->hdr->str_len)
-		return &btf->strings[BTF_STR_OFFSET(offset)];
+	if (offset < btf->hdr->str_len)
+		return &btf->strings[offset];
 	else
 		return NULL;
 }

tools/lib/bpf/libbpf.c

@@ -216,8 +216,8 @@ struct bpf_map {
 	size_t offset;
 	int map_ifindex;
 	struct bpf_map_def def;
-	uint32_t btf_key_id;
-	uint32_t btf_value_id;
+	uint32_t btf_key_type_id;
+	uint32_t btf_value_type_id;
 	void *priv;
 	bpf_map_clear_priv_t clear_priv;
 };
@@ -1074,8 +1074,8 @@ static int bpf_map_find_btf_info(struct bpf_map *map, const struct btf *btf)
 		return -EINVAL;
 	}
 
-	map->btf_key_id = key_id;
-	map->btf_value_id = value_id;
+	map->btf_key_type_id = key_id;
+	map->btf_value_type_id = value_id;
 
 	return 0;
 }
@@ -1100,24 +1100,24 @@ bpf_object__create_maps(struct bpf_object *obj)
 		create_attr.value_size = def->value_size;
 		create_attr.max_entries = def->max_entries;
 		create_attr.btf_fd = 0;
-		create_attr.btf_key_id = 0;
-		create_attr.btf_value_id = 0;
+		create_attr.btf_key_type_id = 0;
+		create_attr.btf_value_type_id = 0;
 
 		if (obj->btf && !bpf_map_find_btf_info(map, obj->btf)) {
 			create_attr.btf_fd = btf__fd(obj->btf);
-			create_attr.btf_key_id = map->btf_key_id;
-			create_attr.btf_value_id = map->btf_value_id;
+			create_attr.btf_key_type_id = map->btf_key_type_id;
+			create_attr.btf_value_type_id = map->btf_value_type_id;
 		}
 
 		*pfd = bpf_create_map_xattr(&create_attr);
-		if (*pfd < 0 && create_attr.btf_key_id) {
+		if (*pfd < 0 && create_attr.btf_key_type_id) {
 			pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
 				   map->name, strerror(errno), errno);
 			create_attr.btf_fd = 0;
-			create_attr.btf_key_id = 0;
-			create_attr.btf_value_id = 0;
-			map->btf_key_id = 0;
-			map->btf_value_id = 0;
+			create_attr.btf_key_type_id = 0;
+			create_attr.btf_value_type_id = 0;
+			map->btf_key_type_id = 0;
+			map->btf_value_type_id = 0;
 			*pfd = bpf_create_map_xattr(&create_attr);
 		}
 
@@ -2085,14 +2085,14 @@ const char *bpf_map__name(struct bpf_map *map)
 	return map ? map->name : NULL;
 }
 
-uint32_t bpf_map__btf_key_id(const struct bpf_map *map)
+uint32_t bpf_map__btf_key_type_id(const struct bpf_map *map)
 {
-	return map ? map->btf_key_id : 0;
+	return map ? map->btf_key_type_id : 0;
 }
 
-uint32_t bpf_map__btf_value_id(const struct bpf_map *map)
+uint32_t bpf_map__btf_value_type_id(const struct bpf_map *map)
 {
-	return map ? map->btf_value_id : 0;
+	return map ? map->btf_value_type_id : 0;
 }
 
 int bpf_map__set_priv(struct bpf_map *map, void *priv,

tools/lib/bpf/libbpf.h

@@ -244,8 +244,8 @@ bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
 int bpf_map__fd(struct bpf_map *map);
 const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
 const char *bpf_map__name(struct bpf_map *map);
-uint32_t bpf_map__btf_key_id(const struct bpf_map *map);
-uint32_t bpf_map__btf_value_id(const struct bpf_map *map);
+uint32_t bpf_map__btf_key_type_id(const struct bpf_map *map);
+uint32_t bpf_map__btf_value_type_id(const struct bpf_map *map);
 
 typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
 int bpf_map__set_priv(struct bpf_map *map, void *priv,