linux_dsm_epyc7002/tools/lib/bpf/btf.h
Stanislav Fomichev 8c4905b995 libbpf: make sure bpf headers are c++ include-able
Wrap headers in extern "C", to turn off C++ mangling.
This simplifies including libbpf in c++ and linking against it.

v2 changes:
* do the same for btf.h

v3 changes:
* test_libbpf.cpp to test for possible future c++ breakages

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-11-21 23:15:41 +01:00

92 lines
2.8 KiB
C

/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/* Copyright (c) 2018 Facebook */
#ifndef __LIBBPF_BTF_H
#define __LIBBPF_BTF_H
#include <linux/types.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifndef LIBBPF_API
#define LIBBPF_API __attribute__((visibility("default")))
#endif
#define BTF_ELF_SEC ".BTF"
#define BTF_EXT_ELF_SEC ".BTF.ext"
struct btf;
struct btf_ext;
struct btf_type;
/*
* The .BTF.ext ELF section layout defined as
* struct btf_ext_header
* func_info subsection
*
* The func_info subsection layout:
* record size for struct bpf_func_info in the func_info subsection
* struct btf_sec_func_info for section #1
* a list of bpf_func_info records for section #1
* where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
* but may not be identical
* struct btf_sec_func_info for section #2
* a list of bpf_func_info records for section #2
* ......
*
* Note that the bpf_func_info record size in .BTF.ext may not
* be the same as the one defined in include/uapi/linux/bpf.h.
* The loader should ensure that record_size meets minimum
* requirement and pass the record as is to the kernel. The
* kernel will handle the func_info properly based on its contents.
*/
struct btf_ext_header {
__u16 magic;
__u8 version;
__u8 flags;
__u32 hdr_len;
/* All offsets are in bytes relative to the end of this header */
__u32 func_info_off;
__u32 func_info_len;
};
struct btf_sec_func_info {
__u32 sec_name_off;
__u32 num_func_info;
/* Followed by num_func_info number of bpf func_info records */
__u8 data[0];
};
typedef int (*btf_print_fn_t)(const char *, ...)
__attribute__((format(printf, 1, 2)));
LIBBPF_API void btf__free(struct btf *btf);
LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size, btf_print_fn_t err_log);
LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
const char *type_name);
LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
__u32 id);
LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
LIBBPF_API int btf__fd(const struct btf *btf);
LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
LIBBPF_API int btf_get_from_id(__u32 id, struct btf **btf);
struct btf_ext *btf_ext__new(__u8 *data, __u32 size, btf_print_fn_t err_log);
void btf_ext__free(struct btf_ext *btf_ext);
int btf_ext__reloc_init(struct btf *btf, struct btf_ext *btf_ext,
const char *sec_name, void **func_info,
__u32 *func_info_rec_size, __u32 *func_info_len);
int btf_ext__reloc(struct btf *btf, struct btf_ext *btf_ext,
const char *sec_name, __u32 insns_cnt, void **func_info,
__u32 *func_info_len);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __LIBBPF_BTF_H */