If no base BTF can be found, fall back to checking for the .BTF.base_ref
section and use it to display raw split BTF. Note that C format output
is not supported for base reference BTF as structs and unions are generally
represented as FWDs.
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/bpf/bpftool/btf.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 91fcb75babe3..f1e0ea06f05f 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -552,6 +552,7 @@ static int do_dump(int argc, char **argv)
struct btf *btf = NULL, *base = NULL;
__u32 root_type_ids[2];
int root_type_cnt = 0;
+ bool c_compat = true;
bool dump_c = false;
__u32 btf_id = -1;
const char *src;
@@ -631,6 +632,21 @@ static int do_dump(int argc, char **argv)
base = get_vmlinux_btf_from_sysfs();
btf = btf__parse_split(*argv, base ?: base_btf);
+ /* Finally check for presence of "base reference" base BTF -
+ * this will allow dumping in raw but not C format, since
+ * base reference BTF will not contain fully-described
+ * structs/unions.
+ */
+ if (!btf && !base && !base_btf) {
+ LIBBPF_OPTS(btf_parse_opts, optp);
+
+ optp.btf_sec = BTF_BASE_REF_ELF_SEC;
+ base_btf = btf__parse_opts(*argv, &optp);
+ if (base_btf)
+ btf = btf__parse_split(*argv, base_btf);
+ if (btf)
+ c_compat = false;
+ }
if (!btf) {
err = -errno;
p_err("failed to load BTF from %s: %s",
@@ -686,6 +702,11 @@ static int do_dump(int argc, char **argv)
}
if (dump_c) {
+ if (!c_compat) {
+ p_err("Cannot represent split BTF with base reference BTF in C format");
+ err = -ENOTSUP;
+ goto done;
+ }
if (json_output) {
p_err("JSON output for C-syntax dump is not supported");
err = -ENOTSUP;
--
2.39.3
