On 11/27/23 6:30 PM, Quentin Deslandes wrote:

+static int bpf_maps_opts_load_btf(struct bpf_map_info *info, struct btf **btf)
+{
+	if (info->btf_vmlinux_value_type_id) {
+		if (!bpf_map_opts.kernel_btf) {
+			bpf_map_opts.kernel_btf = libbpf_find_kernel_btf();
+			if (!bpf_map_opts.kernel_btf) {
+				fprintf(stderr, "ss: failed to load kernel BTF\n");
+				return -1;
+			}
+		}
+
+		*btf = bpf_map_opts.kernel_btf;
+	} else if (info->btf_value_type_id) {
+		*btf = btf__load_from_kernel_by_id(info->btf_id);
+		if (!*btf) {
+			fprintf(stderr, "ss: failed to load BTF for map ID %u\n",
+				info->id);
+			return -1;
+		}
+	} else {
+		*btf = NULL;
+	}
+
+	return 0;
+}

[ ... ]

+static void out_bpf_sk_storage(int map_id, const void *data, size_t len,
+	out_prefix_t *prefix)
+{
+	uint32_t type_id;
+	struct bpf_sk_storage_map_info *map_info;
+
+	map_info = bpf_map_opts_get_info(map_id);
+	if (!map_info) {
+		OUT_P(prefix, "map_id: %d: missing map info", map_id);
+		return;
+	}
+
+	if (map_info->info.value_size != len) {
+		OUT_P(prefix, "map_id: %d: invalid value size, expecting %u, got %lu\n",
+			map_id, map_info->info.value_size, len);
+		return;
+	}
+
+	type_id = map_info->info.btf_vmlinux_value_type_id ?: map_info->info.btf_value_type_id;

sk_storage does not use info.btf_vmlinux_value_type_id, so no need to handle 
this case. Only info.btf_value_type_id is used.

+
+	OUT_P(prefix, "map_id: %d [\n", map_id);
+	out_prefix_push(prefix);
+
+	out_btf_dump_type(map_info->btf, 0, type_id, data, len, prefix);
+
+	out_prefix_pop(prefix);
+	OUT_P(prefix, "]");
+}
+