1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  2/* Copyright (c) 2018 Facebook */
  3
  4#ifndef __LIBBPF_BTF_H
  5#define __LIBBPF_BTF_H
  6
  7#include <stdarg.h>
  8#include <linux/btf.h>
  9#include <linux/types.h>
 10
 11#include "libbpf_common.h"
 12
 13#ifdef __cplusplus
 14extern "C" {
 15#endif
 16
 17#define BTF_ELF_SEC ".BTF"
 18#define BTF_EXT_ELF_SEC ".BTF.ext"
 19#define MAPS_ELF_SEC ".maps"
 20
 21struct btf;
 22struct btf_ext;
 23struct btf_type;
 24
 25struct bpf_object;
 26
 27/*
 28 * The .BTF.ext ELF section layout defined as
 29 *   struct btf_ext_header
 30 *   func_info subsection
 31 *
 32 * The func_info subsection layout:
 33 *   record size for struct bpf_func_info in the func_info subsection
 34 *   struct btf_sec_func_info for section #1
 35 *   a list of bpf_func_info records for section #1
 36 *     where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
 37 *     but may not be identical
 38 *   struct btf_sec_func_info for section #2
 39 *   a list of bpf_func_info records for section #2
 40 *   ......
 41 *
 42 * Note that the bpf_func_info record size in .BTF.ext may not
 43 * be the same as the one defined in include/uapi/linux/bpf.h.
 44 * The loader should ensure that record_size meets minimum
 45 * requirement and pass the record as is to the kernel. The
 46 * kernel will handle the func_info properly based on its contents.
 47 */
 48struct btf_ext_header {
 49	__u16	magic;
 50	__u8	version;
 51	__u8	flags;
 52	__u32	hdr_len;
 53
 54	/* All offsets are in bytes relative to the end of this header */
 55	__u32	func_info_off;
 56	__u32	func_info_len;
 57	__u32	line_info_off;
 58	__u32	line_info_len;
 59
 60	/* optional part of .BTF.ext header */
 61	__u32	field_reloc_off;
 62	__u32	field_reloc_len;
 63};
 64
 65LIBBPF_API void btf__free(struct btf *btf);
 66LIBBPF_API struct btf *btf__new(const void *data, __u32 size);
 67LIBBPF_API struct btf *btf__parse(const char *path, struct btf_ext **btf_ext);
 68LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext);
 69LIBBPF_API struct btf *btf__parse_raw(const char *path);
 70LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
 71LIBBPF_API int btf__load(struct btf *btf);
 72LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
 73				   const char *type_name);
 74LIBBPF_API __s32 btf__find_by_name_kind(const struct btf *btf,
 75					const char *type_name, __u32 kind);
 76LIBBPF_API __u32 btf__get_nr_types(const struct btf *btf);
 77LIBBPF_API const struct btf_type *btf__type_by_id(const struct btf *btf,
 78						  __u32 id);
 79LIBBPF_API size_t btf__pointer_size(const struct btf *btf);
 80LIBBPF_API int btf__set_pointer_size(struct btf *btf, size_t ptr_sz);
 81LIBBPF_API __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
 82LIBBPF_API int btf__resolve_type(const struct btf *btf, __u32 type_id);
 83LIBBPF_API int btf__align_of(const struct btf *btf, __u32 id);
 84LIBBPF_API int btf__fd(const struct btf *btf);
 85LIBBPF_API void btf__set_fd(struct btf *btf, int fd);
 86LIBBPF_API const void *btf__get_raw_data(const struct btf *btf, __u32 *size);
 87LIBBPF_API const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
 88LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
 89LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
 90				    __u32 expected_key_size,
 91				    __u32 expected_value_size,
 92				    __u32 *key_type_id, __u32 *value_type_id);
 93
 94LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
 95LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
 96LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext,
 97					     __u32 *size);
 98LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
 99					const struct btf_ext *btf_ext,
100					const char *sec_name, __u32 insns_cnt,
101					void **func_info, __u32 *cnt);
102LIBBPF_API int btf_ext__reloc_line_info(const struct btf *btf,
103					const struct btf_ext *btf_ext,
104					const char *sec_name, __u32 insns_cnt,
105					void **line_info, __u32 *cnt);
106LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
107LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
108
109LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
110
111struct btf_dedup_opts {
112	unsigned int dedup_table_size;
113	bool dont_resolve_fwds;
114};
115
116LIBBPF_API int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
117			  const struct btf_dedup_opts *opts);
118
119struct btf_dump;
120
121struct btf_dump_opts {
122	void *ctx;
123};
124
125typedef void (*btf_dump_printf_fn_t)(void *ctx, const char *fmt, va_list args);
126
127LIBBPF_API struct btf_dump *btf_dump__new(const struct btf *btf,
128					  const struct btf_ext *btf_ext,
129					  const struct btf_dump_opts *opts,
130					  btf_dump_printf_fn_t printf_fn);
131LIBBPF_API void btf_dump__free(struct btf_dump *d);
132
133LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
134
135struct btf_dump_emit_type_decl_opts {
136	/* size of this struct, for forward/backward compatiblity */
137	size_t sz;
138	/* optional field name for type declaration, e.g.:
139	 * - struct my_struct <FNAME>
140	 * - void (*<FNAME>)(int)
141	 * - char (*<FNAME>)[123]
142	 */
143	const char *field_name;
144	/* extra indentation level (in number of tabs) to emit for multi-line
145	 * type declarations (e.g., anonymous struct); applies for lines
146	 * starting from the second one (first line is assumed to have
147	 * necessary indentation already
148	 */
149	int indent_level;
150	/* strip all the const/volatile/restrict mods */
151	bool strip_mods;
152};
153#define btf_dump_emit_type_decl_opts__last_field strip_mods
154
155LIBBPF_API int
156btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
157			 const struct btf_dump_emit_type_decl_opts *opts);
158
159/*
160 * A set of helpers for easier BTF types handling
161 */
162static inline __u16 btf_kind(const struct btf_type *t)
163{
164	return BTF_INFO_KIND(t->info);
165}
166
167static inline __u16 btf_vlen(const struct btf_type *t)
168{
169	return BTF_INFO_VLEN(t->info);
170}
171
172static inline bool btf_kflag(const struct btf_type *t)
173{
174	return BTF_INFO_KFLAG(t->info);
175}
176
177static inline bool btf_is_void(const struct btf_type *t)
178{
179	return btf_kind(t) == BTF_KIND_UNKN;
180}
181
182static inline bool btf_is_int(const struct btf_type *t)
183{
184	return btf_kind(t) == BTF_KIND_INT;
185}
186
187static inline bool btf_is_ptr(const struct btf_type *t)
188{
189	return btf_kind(t) == BTF_KIND_PTR;
190}
191
192static inline bool btf_is_array(const struct btf_type *t)
193{
194	return btf_kind(t) == BTF_KIND_ARRAY;
195}
196
197static inline bool btf_is_struct(const struct btf_type *t)
198{
199	return btf_kind(t) == BTF_KIND_STRUCT;
200}
201
202static inline bool btf_is_union(const struct btf_type *t)
203{
204	return btf_kind(t) == BTF_KIND_UNION;
205}
206
207static inline bool btf_is_composite(const struct btf_type *t)
208{
209	__u16 kind = btf_kind(t);
210
211	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
212}
213
214static inline bool btf_is_enum(const struct btf_type *t)
215{
216	return btf_kind(t) == BTF_KIND_ENUM;
217}
218
219static inline bool btf_is_fwd(const struct btf_type *t)
220{
221	return btf_kind(t) == BTF_KIND_FWD;
222}
223
224static inline bool btf_is_typedef(const struct btf_type *t)
225{
226	return btf_kind(t) == BTF_KIND_TYPEDEF;
227}
228
229static inline bool btf_is_volatile(const struct btf_type *t)
230{
231	return btf_kind(t) == BTF_KIND_VOLATILE;
232}
233
234static inline bool btf_is_const(const struct btf_type *t)
235{
236	return btf_kind(t) == BTF_KIND_CONST;
237}
238
239static inline bool btf_is_restrict(const struct btf_type *t)
240{
241	return btf_kind(t) == BTF_KIND_RESTRICT;
242}
243
244static inline bool btf_is_mod(const struct btf_type *t)
245{
246	__u16 kind = btf_kind(t);
247
248	return kind == BTF_KIND_VOLATILE ||
249	       kind == BTF_KIND_CONST ||
250	       kind == BTF_KIND_RESTRICT;
251}
252
253static inline bool btf_is_func(const struct btf_type *t)
254{
255	return btf_kind(t) == BTF_KIND_FUNC;
256}
257
258static inline bool btf_is_func_proto(const struct btf_type *t)
259{
260	return btf_kind(t) == BTF_KIND_FUNC_PROTO;
261}
262
263static inline bool btf_is_var(const struct btf_type *t)
264{
265	return btf_kind(t) == BTF_KIND_VAR;
266}
267
268static inline bool btf_is_datasec(const struct btf_type *t)
269{
270	return btf_kind(t) == BTF_KIND_DATASEC;
271}
272
273static inline __u8 btf_int_encoding(const struct btf_type *t)
274{
275	return BTF_INT_ENCODING(*(__u32 *)(t + 1));
276}
277
278static inline __u8 btf_int_offset(const struct btf_type *t)
279{
280	return BTF_INT_OFFSET(*(__u32 *)(t + 1));
281}
282
283static inline __u8 btf_int_bits(const struct btf_type *t)
284{
285	return BTF_INT_BITS(*(__u32 *)(t + 1));
286}
287
288static inline struct btf_array *btf_array(const struct btf_type *t)
289{
290	return (struct btf_array *)(t + 1);
291}
292
293static inline struct btf_enum *btf_enum(const struct btf_type *t)
294{
295	return (struct btf_enum *)(t + 1);
296}
297
298static inline struct btf_member *btf_members(const struct btf_type *t)
299{
300	return (struct btf_member *)(t + 1);
301}
302
303/* Get bit offset of a member with specified index. */
304static inline __u32 btf_member_bit_offset(const struct btf_type *t,
305					  __u32 member_idx)
306{
307	const struct btf_member *m = btf_members(t) + member_idx;
308	bool kflag = btf_kflag(t);
309
310	return kflag ? BTF_MEMBER_BIT_OFFSET(m->offset) : m->offset;
311}
312/*
313 * Get bitfield size of a member, assuming t is BTF_KIND_STRUCT or
314 * BTF_KIND_UNION. If member is not a bitfield, zero is returned.
315 */
316static inline __u32 btf_member_bitfield_size(const struct btf_type *t,
317					     __u32 member_idx)
318{
319	const struct btf_member *m = btf_members(t) + member_idx;
320	bool kflag = btf_kflag(t);
321
322	return kflag ? BTF_MEMBER_BITFIELD_SIZE(m->offset) : 0;
323}
324
325static inline struct btf_param *btf_params(const struct btf_type *t)
326{
327	return (struct btf_param *)(t + 1);
328}
329
330static inline struct btf_var *btf_var(const struct btf_type *t)
331{
332	return (struct btf_var *)(t + 1);
333}
334
335static inline struct btf_var_secinfo *
336btf_var_secinfos(const struct btf_type *t)
337{
338	return (struct btf_var_secinfo *)(t + 1);
339}
340
341#ifdef __cplusplus
342} /* extern "C" */
343#endif
344
345#endif /* __LIBBPF_BTF_H */