/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/* Copyright (c) 2018 Facebook */
/*! \file */
#ifndef __LIBBPF_BTF_H
#define __LIBBPF_BTF_H
#include <stdarg.h>
#include <stdbool.h>
#include <linux/btf.h>
#include <linux/types.h>
#include "libbpf_common.h"
#ifdef __cplusplus
extern "C" {
#endif
#define BTF_ELF_SEC ".BTF"
#define BTF_EXT_ELF_SEC ".BTF.ext"
#define BTF_BASE_ELF_SEC ".BTF.base"
#define MAPS_ELF_SEC ".maps"
struct btf;
struct btf_ext;
struct btf_type;
struct bpf_object;
enum btf_endianness {
BTF_LITTLE_ENDIAN = 0,
BTF_BIG_ENDIAN = 1,
};
/**
* @brief **btf__free()** frees all data of a BTF object
* @param btf BTF object to free
*/
LIBBPF_API void btf__free(struct btf *btf);
/**
* @brief **btf__new()** creates a new instance of a BTF object from the raw
* bytes of an ELF's BTF section
* @param data raw bytes
* @param size number of bytes passed in `data`
* @return new BTF object instance which has to be eventually freed with
* **btf__free()**
*
* On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
* error code from such a pointer `libbpf_get_error()` should be used. If
* `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
* returned on error instead. In both cases thread-local `errno` variable is
* always set to error code as well.
*/
LIBBPF_API struct btf *btf__new(const void *data, __u32 size);
/**
* @brief **btf__new_split()** create a new instance of a BTF object from the
* provided raw data bytes. It takes another BTF instance, **base_btf**, which
* serves as a base BTF, which is extended by types in a newly created BTF
* instance
* @param data raw bytes
* @param size length of raw bytes
* @param base_btf the base BTF object
* @return new BTF object instance which has to be eventually freed with
* **btf__free()**
*
* If *base_btf* is NULL, `btf__new_split()` is equivalent to `btf__new()` and
* creates non-split BTF.
*
* On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
* error code from such a pointer `libbpf_get_error()` should be used. If
* `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
* returned on error instead. In both cases thread-local `errno` variable is
* always set to error code as well.
*/
LIBBPF_API struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_btf);
/**
* @brief **btf__new_empty()** creates an empty BTF object. Use
* `btf__add_*()` to populate such BTF object.
* @return new BTF object instance which has to be eventually freed with
* **btf__free()**
*
* On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
* error code from such a pointer `libbpf_get_error()` should be used. If
* `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
* returned on error instead. In both cases thread-local `errno` variable is
* always set to error code as well.
*/
LIBBPF_API struct btf *btf__new_empty(void);
/**
* @brief **btf__new_empty_split()** creates an unpopulated BTF object from an
* ELF BTF section except with a base BTF on top of which split BTF should be
* based
* @return new BTF object instance which has to be eventually freed with
* **btf__free()**
*
* If *base_btf* is NULL, `btf__new_empty_split()` is equivalent to
* `btf__new_empty()` and creates non-split BTF.
*
* On error, error-code-encoded-as-pointer is returned, not a NULL. To extract
* error code from such a pointer `libbpf_get_error()` should be used. If
* `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is
* returned on error instead. In both cases thread-local `errno` variable is
* always set to error code as well.
*/
LIBBPF_API struct btf *btf__new_empty_split(struct btf *base_btf);
/**
* @brief **btf__distill_base()** creates new versions of the split BTF
* *src_btf* and its base BTF. The new base BTF will only contain the types
* needed to improve robustness of the split BTF to small changes in base BTF.
* When that split BTF is loaded against a (possibly changed) base, this
* distilled base BTF will help update references to that (possibly changed)
* base BTF.
*
* Both the new split and its associated new base BTF must be freed by
* the caller.
*
* If successful, 0 is returned and **new_base_btf** and **new_split_btf**
* will point at new base/split BTF. Both the new split and its associated
* new base BTF must be freed by the caller.
*
* A negative value is returned on error and the thread-local `errno` variable
* is set to the error code as well.
*/
LIBBPF_API int btf__distill_base(const struct btf *src_btf, struct btf **new_base_btf,
struct btf **new_split_btf);
LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
LIBBPF_API struct btf *btf__parse_split(const char *path, struct btf *base_btf);
LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_btf);
LIBBPF_API struct btf *btf__parse_raw(const char *path);
LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf);
LIBBPF_API struct btf *btf__load_vmlinux_btf(void);
LIBBPF_API struct btf *btf__load_module_btf(const char *module_name, struct btf *vmlinux_btf);
LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
LIBBPF_API int btf__load_into_kernel(struct btf *btf);
LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
const char *type_name);
LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
const char *type_name, __u32 kind);
LIBBPF_API __u32 btf__type_cnt(const struct btf *btf);
LIBBPF_API const struct btf *btf__base_btf(const struct btf *btf);
LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
__u32 id);
LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
LIBBPF_API enum btf_endianness btf__endianness(const struct btf *btf);
LIBBPF_API int btf__set_endianness(struct btf *btf, enum btf_endianness endian);
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__align_of(const struct btf *btf, __u32 id);
LIBBPF_API int btf__fd(const struct btf *btf);
LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
LIBBPF_API const void *btf__raw_data(const struct btf *btf, __u32 *size);
LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
LIBBPF_API const char *btf__str_by_offset(const struct btf *btf, __u32 offset);
LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size);
LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
LIBBPF_API const void *btf_ext__raw_data(const struct btf_ext *btf_ext, __u32 *size);
LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
LIBBPF_API int btf__add_type(struct btf *btf, const struct btf *src_btf,
const struct btf_type *src_type);
/**
* @brief **btf__add_btf()** appends all the BTF types from *src_btf* into *btf*
* @param btf BTF object which all the BTF types and strings are added to
* @param src_btf BTF object which all BTF types and referenced strings are copied from
* @return BTF type ID of the first appended BTF type, or negative error code
*
* **btf__add_btf()** can be used to simply and efficiently append the entire
* contents of one BTF object to another one. All the BTF type data is copied
* over, all referenced type IDs are adjusted by adding a necessary ID offset.
* Only strings referenced from BTF types are copied over and deduplicated, so
* if there were some unused strings in *src_btf*, those won't be copied over,
* which is consistent with the general string deduplication semantics of BTF
* writing APIs.
*
* If any error is encountered during this process, the contents of *btf* is
* left intact, which means that **btf__add_btf()** follows the transactional
* semantics and the operation as a whole is all-or-nothing.
*
* *src_btf* has to be non-split BTF, as of now copying types from split BTF
* is not supported and will result in -ENOTSUP error code returned.
*/
LIBBPF_API int btf__add_btf(struct btf *btf, const struct btf *src_btf);
LIBBPF_API int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding);
LIBBPF_API int btf__add_float(struct btf *btf, const char *name, size_t byte_sz);
LIBBPF_API int btf__add_ptr(struct btf *btf, int ref_type_id);
LIBBPF_API int btf__add_array(struct btf *btf,
int index_type_id, int elem_type_id, __u32 nr_elems);
/* struct/union construction APIs */
LIBBPF_API int btf__add_struct(struct btf *btf, const char *name, __u32 sz);
LIBBPF_API int btf__add_union(struct btf *btf, const char *name, __u32 sz);
LIBBPF_API int btf__add_field(struct btf *btf, const char *name, int field_type_id,
__u32 bit_offset, __u32 bit_size);
/* enum construction APIs */
LIBBPF_API int btf__add_enum(struct btf *btf, const char *name, __u32 bytes_sz);
LIBBPF_API int btf__add_enum_value(struct btf *btf, const char *name, __s64 value);
LIBBPF_API int btf__add_enum64(struct btf *btf, const char *name, __u32 bytes_sz, bool is_signed);
LIBBPF_API int btf__add_enum64_value(struct btf *btf, const char *name, __u64 value);
enum btf_fwd_kind {
BTF_FWD_STRUCT = 0,
BTF_FWD_UNION = 1,
BTF_FWD_ENUM = 2,
};
LIBBPF_API int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind);
LIBBPF_API int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id);
LIBBPF_API int btf__add_volatile(struct btf *btf, int ref_type_id);
LIBBPF_API int btf__add_const(struct btf *btf, int ref_type_id);
LIBBPF_API int btf__add_restrict(struct btf *btf, int ref_type_id);
LIBBPF_API int btf__add_type_tag(struct btf *btf, const char *value, int ref_type_id);
/* func and func_proto construction APIs */
LIBBPF_API int btf__add_func(struct btf *btf, const char *name,
enum btf_func_linkage linkage, int proto_type_id);
LIBBPF_API int btf__add_func_proto(struct btf *btf, int ret_type_id);
LIBBPF_API int btf__add_func_param(struct btf *btf, const char *name, int type_id);
/* var & datasec construction APIs */
LIBBPF_API int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id);
LIBBPF_API int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz);
LIBBPF_API int btf__add_datasec_var_info(struct btf *btf, int var_type_id,
__u32 offset, __u32 byte_sz);
/* tag construction API */
LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
int component_idx);
struct btf_dedup_opts {
size_t sz;
/* optional .BTF.ext info to dedup along the main BTF info */
struct btf_ext *btf_ext;
/* force hash collisions (used for testing) */
bool force_collisions;
size_t :0;
};
#define btf_dedup_opts__last_field force_collisions
LIBBPF_API int btf__dedup(struct btf *btf, const struct btf_dedup_opts *opts);
/**
* @brief **btf__relocate()** will check the split BTF *btf* for references
* to base BTF kinds, and verify those references are compatible with
* *base_btf*; if they are, *btf* is adjusted such that is re-parented to
* *base_btf* and type ids and strings are adjusted to accommodate this.
*
* If successful, 0 is returned and **btf** now has **base_btf** as its
* base.
*
* A negative value is returned on error and the thread-local `errno` variable
* is set to the error code as well.
*/
LIBBPF_API int btf__relocate(struct btf *btf, const struct btf *base_btf);
struct btf_dump;
struct btf_dump_opts {
size_t sz;
};
#define btf_dump_opts__last_field sz
typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
btf_dump_printf_fn_t printf_fn,
void *ctx,
const struct btf_dump_opts *opts);
LIBBPF_API void btf_dump__free(struct btf_dump *d);
LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
struct btf_dump_emit_type_decl_opts {
/* size of this struct, for forward/backward compatibility */
size_t sz;
/* optional field name for type declaration, e.g.:
* - struct my_struct <FNAME>
* - void (*<FNAME>)(int)
* - char (*<FNAME>)[123]
*/
const char *field_name;
/* extra indentation level (in number of tabs) to emit for multi-line
* type declarations (e.g., anonymous struct); applies for lines
* starting from the second one (first line is assumed to have
* necessary indentation already
*/
int indent_level;
/* strip all the const/volatile/restrict mods */
bool strip_mods;
size_t :0;
};
#define btf_dump_emit_type_decl_opts__last_field strip_mods
LIBBPF_API int
btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
const struct btf_dump_emit_type_decl_opts *opts);
struct btf_dump_type_data_opts {
/* size of this struct, for forward/backward compatibility */
size_t sz;
const char *indent_str;
int indent_level;
/* below match "show" flags for bpf_show_snprintf() */
bool compact; /* no newlines/indentation */
bool skip_names; /* skip member/type names */
bool emit_zeroes; /* show 0-valued fields */
size_t :0;
};
#define btf_dump_type_data_opts__last_field emit_zeroes
LIBBPF_API int
btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
const void *data, size_t data_sz,
const struct btf_dump_type_data_opts *opts);
/*
* A set of helpers for easier BTF types handling.
*
* The inline functions below rely on constants from the kernel headers which
* may not be available for applications including this header file. To avoid
* compilation errors, we define all the constants here that were added after
* the initial introduction of the BTF_KIND* constants.
*/
#ifndef BTF_KIND_FUNC
#define BTF_KIND_FUNC 12 /* Function */
#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */
#endif
#ifndef BTF_KIND_VAR
#define BTF_KIND_VAR 14 /* Variable */
#define BTF_KIND_DATASEC 15 /* Section */
#endif
#ifndef BTF_KIND_FLOAT
#define BTF_KIND_FLOAT 16 /* Floating point */
#endif
/* The kernel header switched to enums, so the following were never #defined */
#define BTF_KIND_DECL_TAG 17 /* Decl Tag */
#define BTF_KIND_TYPE_TAG 18 /* Type Tag */
#define BTF_KIND_ENUM64 19 /* Enum for up-to 64bit values */
static inline __u16 btf_kind(const struct btf_type *t)
{
return BTF_INFO_KIND(t->info);
}
static inline __u16 btf_vlen(const struct btf_type *t)
{
return BTF_INFO_VLEN(t->info);
}
static inline bool btf_kflag(const struct btf_type *t)
{
return BTF_INFO_KFLAG(t->info);
}
static inline bool btf_is_void(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_UNKN;
}
static inline bool btf_is_int(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_INT;
}
static inline bool btf_is_ptr(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_PTR;
}
static inline bool btf_is_array(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_ARRAY;
}
static inline bool btf_is_struct(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_STRUCT;
}
static inline bool btf_is_union(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_UNION;
}
static inline bool btf_is_composite(const struct btf_type *t)
{
__u16 kind = btf_kind(t);
return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
}
static inline bool btf_is_enum(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_ENUM;
}
static inline bool btf_is_enum64(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_ENUM64;
}
static inline bool btf_is_fwd(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_FWD;
}
static inline bool btf_is_typedef(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_TYPEDEF;
}
static inline bool btf_is_volatile(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_VOLATILE;
}
static inline bool btf_is_const(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_CONST;
}
static inline bool btf_is_restrict(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_RESTRICT;
}
static inline bool btf_is_mod(const struct btf_type *t)
{
__u16 kind = btf_kind(t);
return kind == BTF_KIND_VOLATILE ||
kind == BTF_KIND_CONST ||
kind == BTF_KIND_RESTRICT ||
kind == BTF_KIND_TYPE_TAG;
}
static inline bool btf_is_func(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_FUNC;
}
static inline bool btf_is_func_proto(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_FUNC_PROTO;
}
static inline bool btf_is_var(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_VAR;
}
static inline bool btf_is_datasec(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_DATASEC;
}
static inline bool btf_is_float(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_FLOAT;
}
static inline bool btf_is_decl_tag(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_DECL_TAG;
}
static inline bool btf_is_type_tag(const struct btf_type *t)
{
return btf_kind(t) == BTF_KIND_TYPE_TAG;
}
static inline bool btf_is_any_enum(const struct btf_type *t)
{
return btf_is_enum(t) || btf_is_enum64(t);
}
static inline bool btf_kind_core_compat(const struct btf_type *t1,
const struct btf_type *t2)
{
return btf_kind(t1) == btf_kind(t2) ||
(btf_is_any_enum(t1) && btf_is_any_enum(t2));
}
static inline __u8 btf_int_encoding(const struct btf_type *t)
{
return BTF_INT_ENCODING(*(__u32 *)(t + 1));
}
static inline __u8 btf_int_offset(const struct btf_type *t)
{
return BTF_INT_OFFSET(*(__u32 *)(t + 1));
}
static inline __u8 btf_int_bits(const struct btf_type *t)
{
return BTF_INT_BITS(*(__u32 *)(t + 1));
}
static inline struct btf_array *btf_array(const struct btf_type *t)
{
return (struct btf_array *)(t + 1);
}
static inline struct btf_enum *btf_enum(const struct btf_type *t)
{
return (struct btf_enum *)(t + 1);
}
struct btf_enum64;
static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
{
return (struct btf_enum64 *)(t + 1);
}
static inline __u64 btf_enum64_value(const struct btf_enum64 *e)
{
/* struct btf_enum64 is introduced in Linux 6.0, which is very
* bleeding-edge. Here we are avoiding relying on struct btf_enum64
* definition coming from kernel UAPI headers to support wider range
* of system-wide kernel headers.
*
* Given this header can be also included from C++ applications, that
* further restricts C tricks we can use (like using compatible
* anonymous struct). So just treat struct btf_enum64 as
* a three-element array of u32 and access second (lo32) and third
* (hi32) elements directly.
*
* For reference, here is a struct btf_enum64 definition:
*
* const struct btf_enum64 {
* __u32 name_off;
* __u32 val_lo32;
* __u32 val_hi32;
* };
*/
const __u32 *e64 = (const __u32 *)e;
return ((__u64)e64[2] << 32) | e64[1];
}
static inline struct btf_member *btf_members(const struct btf_type *t)
{
return (struct btf_member *)(t + 1);
}
/* Get bit offset of a member with specified index. */
static inline __u32 btf_member_bit_offset(const struct btf_type *t,
__u32 member_idx)
{
const struct btf_member *m = btf_members(t) + member_idx;
bool kflag = btf_kflag(t);
return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
}
/*
* Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
* BTF_KIND_UNION. If member is not a bitfield, zero is returned.
*/
static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
__u32 member_idx)
{
const struct btf_member *m = btf_members(t) + member_idx;
bool kflag = btf_kflag(t);
return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
}
static inline struct btf_param *btf_params(const struct btf_type *t)
{
return (struct btf_param *)(t + 1);
}
static inline struct btf_var *btf_var(const struct btf_type *t)
{
return (struct btf_var *)(t + 1);
}
static inline struct btf_var_secinfo *
btf_var_secinfos(const struct btf_type *t)
{
return (struct btf_var_secinfo *)(t + 1);
}
struct btf_decl_tag;
static inline struct btf_decl_tag *btf_decl_tag(const struct btf_type *t)
{
return (struct btf_decl_tag *)(t + 1);
}
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __LIBBPF_BTF_H */
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