bcc: Get rid of deprecated libbpf API btf__get_map_kv_tids()

btf__get_map_kv_tids() is deprecated and causes annoying compilation warnings.
Reimplement it in BCC.

Signed-off-by: Hengqi Chen <[email protected]>

src/cc/bcc_btf.cc

@@ -652,9 +652,47 @@ int BTF::get_btf_info(const char *fname,
 int BTF::get_map_tids(std::string map_name,
  unsigned expected_ksize, unsigned expected_vsize,
  unsigned *key_tid, unsigned *value_tid) {
- return btf__get_map_kv_tids(btf_, map_name.c_str(),
- expected_ksize, expected_vsize,
- key_tid, value_tid);
+ auto struct_name = "____btf_map_" + map_name;
+ auto type_id = btf__find_by_name_kind(btf_, struct_name.c_str(), BTF_KIND_STRUCT);
+ if (type_id < 0) {
+ warning("struct %s not found in BTF\n", struct_name.c_str());
+ return -1;
+ }
+
+ auto struct_type = btf__type_by_id(btf_, type_id);
+ if (!struct_type || btf_vlen(struct_type) < 2) {
+ warning("struct %s is not a valid map struct\n", struct_name.c_str());
+ return -1;
+ }
+
+ auto members = btf_members(struct_type);
+ auto key = members[0];
+ auto key_name = btf__name_by_offset(btf_, key.name_off);
+ if (strcmp(key_name, "key")) {
+ warning("'key' should be the first member\n");
+ return -1;
+ }
+ auto key_size = btf__resolve_size(btf_, key.type);
+ if (key_size != expected_ksize) {
+ warning("expect key size to be %d, got %d\n", expected_ksize, key_size);
+ return -1;
+ }
+ *key_tid = key.type;
+
+ auto value = members[1];
+ auto value_name = btf__name_by_offset(btf_, value.name_off);
+ if (strcmp(value_name, "value")) {
+ warning("'value' should be the second member\n");
+ return -1;
+ }
+ auto value_size = btf__resolve_size(btf_, value.type);
+ if (value_size != expected_vsize) {
+ warning("expect value size to be %d, got %d\n", expected_vsize, value_size);
+ return -1;
+ }
+ *value_tid = value.type;
+
+ return 0;
 }
 
 } // namespace ebpf

src/cc/bcc_btf.h

@@ -26,6 +26,7 @@
 #include "bpf_module.h"
 
 struct btf;
+struct btf_type;
 
 namespace btf_ext_vendored {