[PATCH v2 bpf-next 10/17] libbpf: tighten BTF type ID rewriting with error checking

[Andrii Nakryiko]

It should never fail, but if it does, it's better to know about this rather
than end up with nonsensical type IDs.

Signed-off-by: Andrii Nakryiko <and...@kernel.org>
---
 tools/lib/bpf/linker.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index 283249df9831..d5dc1d401f57 100644
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -1423,6 +1423,15 @@ static int linker_fixup_btf(struct src_obj *obj)
 static int remap_type_id(__u32 *type_id, void *ctx)
 {
        int *id_map = ctx;
+       int new_id = id_map[*type_id];
+
+       if (*type_id == 0)
+               return 0;
+
+       if (new_id == 0) {
+               pr_warn("failed to find new ID mapping for original BTF type ID 
%u\n", *type_id);
+               return -EINVAL;
+       }
 
        *type_id = id_map[*type_id];
 
-- 
2.30.2