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author | Daniel Müller <deso@posteo.net> | 2022-06-28 16:01:21 +0000 |
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committer | Andrii Nakryiko <andrii@kernel.org> | 2022-07-05 21:14:25 -0700 |
commit | ec6209c8d42f815bc3bef10934637ca92114cd1b (patch) | |
tree | 9366cf9645bdc5273cb8e93e0a109fe3f63d65a7 /tools/lib/bpf/libbpf.c | |
parent | bpftool: Honor BPF_CORE_TYPE_MATCHES relocation (diff) | |
download | linux-dev-ec6209c8d42f815bc3bef10934637ca92114cd1b.tar.xz linux-dev-ec6209c8d42f815bc3bef10934637ca92114cd1b.zip |
bpf, libbpf: Add type match support
This patch adds support for the proposed type match relation to
relo_core where it is shared between userspace and kernel. It plumbs
through both kernel-side and libbpf-side support.
The matching relation is defined as follows (copy from source):
- modifiers and typedefs are stripped (and, hence, effectively ignored)
- generally speaking types need to be of same kind (struct vs. struct, union
vs. union, etc.)
- exceptions are struct/union behind a pointer which could also match a
forward declaration of a struct or union, respectively, and enum vs.
enum64 (see below)
Then, depending on type:
- integers:
- match if size and signedness match
- arrays & pointers:
- target types are recursively matched
- structs & unions:
- local members need to exist in target with the same name
- for each member we recursively check match unless it is already behind a
pointer, in which case we only check matching names and compatible kind
- enums:
- local variants have to have a match in target by symbolic name (but not
numeric value)
- size has to match (but enum may match enum64 and vice versa)
- function pointers:
- number and position of arguments in local type has to match target
- for each argument and the return value we recursively check match
Signed-off-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220628160127.607834-5-deso@posteo.net
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
-rw-r--r-- | tools/lib/bpf/libbpf.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 8a45a84eb9b2..64c4cc6140d3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5470,6 +5470,12 @@ int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id, 32); } +int bpf_core_types_match(const struct btf *local_btf, __u32 local_id, + const struct btf *targ_btf, __u32 targ_id) +{ + return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false, 32); +} + static size_t bpf_core_hash_fn(const void *key, void *ctx) { return (size_t)key; |