libbpf: Allow version suffixes (___smth) for struct_ops types

E.g. allow the following struct_ops definitions:

    struct bpf_testmod_ops___v1 { int (*test)(void); };
    struct bpf_testmod_ops___v2 { int (*test)(void); };

    SEC(".struct_ops.link")
    struct bpf_testmod_ops___v1 a = { .test = ... }
    SEC(".struct_ops.link")
    struct bpf_testmod_ops___v2 b = { .test = ... }

Where both bpf_testmod_ops__v1 and bpf_testmod_ops__v2 would be
resolved as 'struct bpf_testmod_ops' from kernel BTF.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240306104529.6453-2-eddyz87@gmail.com

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6c2979f1b4712d6db9e2599fc8b5694bf95ede1b..e2a4c409980b5833bf6c09180ebfb6d1151ae65a 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -948,7 +948,7 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
                                   const char *name, __u32 kind);
 
 static int
-find_struct_ops_kern_types(struct bpf_object *obj, const char *tname,
+find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw,
                           struct module_btf **mod_btf,
                           const struct btf_type **type, __u32 *type_id,
                           const struct btf_type **vtype, __u32 *vtype_id,
@@ -958,8 +958,12 @@ find_struct_ops_kern_types(struct bpf_object *obj, const char *tname,
        const struct btf_member *kern_data_member;
        struct btf *btf;
        __s32 kern_vtype_id, kern_type_id;
+       char tname[256];
        __u32 i;
 
+       snprintf(tname, sizeof(tname), "%.*s",
+                (int)bpf_core_essential_name_len(tname_raw), tname_raw);
+
        kern_type_id = find_ksym_btf_id(obj, tname, BTF_KIND_STRUCT,
                                        &btf, mod_btf);
        if (kern_type_id < 0) {