1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (c) 2018 Facebook */
7 #include <linux/types.h>
8 #include <linux/bpfptr.h>
9 #include <linux/bsearch.h>
10 #include <linux/btf_ids.h>
11 #include <uapi/linux/btf.h>
12 #include <uapi/linux/bpf.h>
14 #define BTF_TYPE_EMIT(type) ((void)(type *)0)
15 #define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val)
17 /* These need to be macros, as the expressions are used in assembler input */
18 #define KF_ACQUIRE (1 << 0) /* kfunc is an acquire function */
19 #define KF_RELEASE (1 << 1) /* kfunc is a release function */
20 #define KF_RET_NULL (1 << 2) /* kfunc returns a pointer that may be NULL */
21 #define KF_KPTR_GET (1 << 3) /* kfunc returns reference to a kptr */
22 /* Trusted arguments are those which are meant to be referenced arguments with
23 * unchanged offset. It is used to enforce that pointers obtained from acquire
24 * kfuncs remain unmodified when being passed to helpers taking trusted args.
37 * struct foo *f = alloc_foo(); // Acquire kfunc
38 * struct bar *b = alloc_bar(); // Acquire kfunc
40 * If a kfunc set_foo_data() wants to operate only on the allocated object, it
41 * will set the KF_TRUSTED_ARGS flag, which will prevent unsafe usage like:
43 * set_foo_data(f, 42); // Allowed
44 * set_foo_data(f->next, 42); // Rejected, non-referenced pointer
45 * set_foo_data(&f->next, 42);// Rejected, referenced, but wrong type
46 * set_foo_data(&b->f, 42); // Rejected, referenced, but bad offset
48 * In the final case, usually for the purposes of type matching, it is deduced
49 * by looking at the type of the member at the offset, but due to the
50 * requirement of trusted argument, this deduction will be strict and not done
53 #define KF_TRUSTED_ARGS (1 << 4) /* kfunc only takes trusted pointer arguments */
54 #define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */
55 #define KF_DESTRUCTIVE (1 << 6) /* kfunc performs destructive actions */
58 * Return the name of the passed struct, if exists, or halt the build if for
59 * example the structure gets renamed. In this way, developers have to revisit
60 * the code using that structure name, and update it accordingly.
62 #define stringify_struct(x) \
63 ({ BUILD_BUG_ON(sizeof(struct x) < 0); \
73 struct btf_kfunc_id_set {
75 struct btf_id_set8 *set;
78 struct btf_id_dtor_kfunc {
83 struct btf_struct_meta {
85 struct btf_record *record;
86 struct btf_field_offs *field_offs;
89 struct btf_struct_metas {
91 struct btf_struct_meta types[];
94 typedef void (*btf_dtor_kfunc_t)(void *);
96 extern const struct file_operations btf_fops;
98 void btf_get(struct btf *btf);
99 void btf_put(struct btf *btf);
100 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr);
101 struct btf *btf_get_by_fd(int fd);
102 int btf_get_info_by_fd(const struct btf *btf,
103 const union bpf_attr *attr,
104 union bpf_attr __user *uattr);
105 /* Figure out the size of a type_id. If type_id is a modifier
106 * (e.g. const), it will be resolved to find out the type with size.
109 * In describing "const void *", type_id is "const" and "const"
110 * refers to "void *". The return type will be "void *".
112 * If type_id is a simple "int", then return type will be "int".
114 * @btf: struct btf object
115 * @type_id: Find out the size of type_id. The type_id of the return
116 * type is set to *type_id.
117 * @ret_size: It can be NULL. If not NULL, the size of the return
118 * type is set to *ret_size.
119 * Return: The btf_type (resolved to another type with size info if needed).
120 * NULL is returned if type_id itself does not have size info
121 * (e.g. void) or it cannot be resolved to another type that
123 * *type_id and *ret_size will not be changed in the
126 const struct btf_type *btf_type_id_size(const struct btf *btf,
131 * Options to control show behaviour.
132 * - BTF_SHOW_COMPACT: no formatting around type information
133 * - BTF_SHOW_NONAME: no struct/union member names/types
134 * - BTF_SHOW_PTR_RAW: show raw (unobfuscated) pointer values;
136 * - BTF_SHOW_ZERO: show zero-valued struct/union members; they
137 * are not displayed by default
138 * - BTF_SHOW_UNSAFE: skip use of bpf_probe_read() to safely read
139 * data before displaying it.
141 #define BTF_SHOW_COMPACT BTF_F_COMPACT
142 #define BTF_SHOW_NONAME BTF_F_NONAME
143 #define BTF_SHOW_PTR_RAW BTF_F_PTR_RAW
144 #define BTF_SHOW_ZERO BTF_F_ZERO
145 #define BTF_SHOW_UNSAFE (1ULL << 4)
147 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
149 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, void *obj,
150 struct seq_file *m, u64 flags);
153 * Copy len bytes of string representation of obj of BTF type_id into buf.
155 * @btf: struct btf object
156 * @type_id: type id of type obj points to
157 * @obj: pointer to typed data
158 * @buf: buffer to write to
159 * @len: maximum length to write to buf
160 * @flags: show options (see above)
162 * Return: length that would have been/was copied as per snprintf, or
165 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
166 char *buf, int len, u64 flags);
168 int btf_get_fd_by_id(u32 id);
169 u32 btf_obj_id(const struct btf *btf);
170 bool btf_is_kernel(const struct btf *btf);
171 bool btf_is_module(const struct btf *btf);
172 struct module *btf_try_get_module(const struct btf *btf);
173 u32 btf_nr_types(const struct btf *btf);
174 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
175 const struct btf_member *m,
176 u32 expected_offset, u32 expected_size);
177 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
178 int btf_find_timer(const struct btf *btf, const struct btf_type *t);
179 struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
180 u32 field_mask, u32 value_size);
181 int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec);
182 struct btf_field_offs *btf_parse_field_offs(struct btf_record *rec);
183 bool btf_type_is_void(const struct btf_type *t);
184 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
185 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
186 u32 id, u32 *res_id);
187 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
188 u32 id, u32 *res_id);
189 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
190 u32 id, u32 *res_id);
191 const struct btf_type *
192 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
194 const char *btf_type_str(const struct btf_type *t);
196 #define for_each_member(i, struct_type, member) \
197 for (i = 0, member = btf_type_member(struct_type); \
198 i < btf_type_vlen(struct_type); \
201 #define for_each_vsi(i, datasec_type, member) \
202 for (i = 0, member = btf_type_var_secinfo(datasec_type); \
203 i < btf_type_vlen(datasec_type); \
206 static inline bool btf_type_is_ptr(const struct btf_type *t)
208 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
211 static inline bool btf_type_is_int(const struct btf_type *t)
213 return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
216 static inline bool btf_type_is_small_int(const struct btf_type *t)
218 return btf_type_is_int(t) && t->size <= sizeof(u64);
221 static inline bool btf_type_is_enum(const struct btf_type *t)
223 return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM;
226 static inline bool btf_is_any_enum(const struct btf_type *t)
228 return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM ||
229 BTF_INFO_KIND(t->info) == BTF_KIND_ENUM64;
232 static inline bool btf_kind_core_compat(const struct btf_type *t1,
233 const struct btf_type *t2)
235 return BTF_INFO_KIND(t1->info) == BTF_INFO_KIND(t2->info) ||
236 (btf_is_any_enum(t1) && btf_is_any_enum(t2));
239 static inline bool str_is_empty(const char *s)
244 static inline u16 btf_kind(const struct btf_type *t)
246 return BTF_INFO_KIND(t->info);
249 static inline bool btf_is_enum(const struct btf_type *t)
251 return btf_kind(t) == BTF_KIND_ENUM;
254 static inline bool btf_is_enum64(const struct btf_type *t)
256 return btf_kind(t) == BTF_KIND_ENUM64;
259 static inline u64 btf_enum64_value(const struct btf_enum64 *e)
261 return ((u64)e->val_hi32 << 32) | e->val_lo32;
264 static inline bool btf_is_composite(const struct btf_type *t)
266 u16 kind = btf_kind(t);
268 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
271 static inline bool btf_is_array(const struct btf_type *t)
273 return btf_kind(t) == BTF_KIND_ARRAY;
276 static inline bool btf_is_int(const struct btf_type *t)
278 return btf_kind(t) == BTF_KIND_INT;
281 static inline bool btf_is_ptr(const struct btf_type *t)
283 return btf_kind(t) == BTF_KIND_PTR;
286 static inline u8 btf_int_offset(const struct btf_type *t)
288 return BTF_INT_OFFSET(*(u32 *)(t + 1));
291 static inline u8 btf_int_encoding(const struct btf_type *t)
293 return BTF_INT_ENCODING(*(u32 *)(t + 1));
296 static inline bool btf_type_is_scalar(const struct btf_type *t)
298 return btf_type_is_int(t) || btf_type_is_enum(t);
301 static inline bool btf_type_is_typedef(const struct btf_type *t)
303 return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF;
306 static inline bool btf_type_is_volatile(const struct btf_type *t)
308 return BTF_INFO_KIND(t->info) == BTF_KIND_VOLATILE;
311 static inline bool btf_type_is_func(const struct btf_type *t)
313 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
316 static inline bool btf_type_is_func_proto(const struct btf_type *t)
318 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
321 static inline bool btf_type_is_var(const struct btf_type *t)
323 return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
326 static inline bool btf_type_is_type_tag(const struct btf_type *t)
328 return BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG;
331 /* union is only a special case of struct:
332 * all its offsetof(member) == 0
334 static inline bool btf_type_is_struct(const struct btf_type *t)
336 u8 kind = BTF_INFO_KIND(t->info);
338 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
341 static inline bool __btf_type_is_struct(const struct btf_type *t)
343 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
346 static inline bool btf_type_is_array(const struct btf_type *t)
348 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
351 static inline u16 btf_type_vlen(const struct btf_type *t)
353 return BTF_INFO_VLEN(t->info);
356 static inline u16 btf_vlen(const struct btf_type *t)
358 return btf_type_vlen(t);
361 static inline u16 btf_func_linkage(const struct btf_type *t)
363 return BTF_INFO_VLEN(t->info);
366 static inline bool btf_type_kflag(const struct btf_type *t)
368 return BTF_INFO_KFLAG(t->info);
371 static inline u32 __btf_member_bit_offset(const struct btf_type *struct_type,
372 const struct btf_member *member)
374 return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
378 static inline u32 __btf_member_bitfield_size(const struct btf_type *struct_type,
379 const struct btf_member *member)
381 return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
385 static inline struct btf_member *btf_members(const struct btf_type *t)
387 return (struct btf_member *)(t + 1);
390 static inline u32 btf_member_bit_offset(const struct btf_type *t, u32 member_idx)
392 const struct btf_member *m = btf_members(t) + member_idx;
394 return __btf_member_bit_offset(t, m);
397 static inline u32 btf_member_bitfield_size(const struct btf_type *t, u32 member_idx)
399 const struct btf_member *m = btf_members(t) + member_idx;
401 return __btf_member_bitfield_size(t, m);
404 static inline const struct btf_member *btf_type_member(const struct btf_type *t)
406 return (const struct btf_member *)(t + 1);
409 static inline struct btf_array *btf_array(const struct btf_type *t)
411 return (struct btf_array *)(t + 1);
414 static inline struct btf_enum *btf_enum(const struct btf_type *t)
416 return (struct btf_enum *)(t + 1);
419 static inline struct btf_enum64 *btf_enum64(const struct btf_type *t)
421 return (struct btf_enum64 *)(t + 1);
424 static inline const struct btf_var_secinfo *btf_type_var_secinfo(
425 const struct btf_type *t)
427 return (const struct btf_var_secinfo *)(t + 1);
430 static inline struct btf_param *btf_params(const struct btf_type *t)
432 return (struct btf_param *)(t + 1);
435 static inline int btf_id_cmp_func(const void *a, const void *b)
437 const int *pa = a, *pb = b;
442 static inline bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
444 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
447 static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
449 return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
453 struct bpf_verifier_log;
455 #ifdef CONFIG_BPF_SYSCALL
456 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
457 const char *btf_name_by_offset(const struct btf *btf, u32 offset);
458 struct btf *btf_parse_vmlinux(void);
459 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
460 u32 *btf_kfunc_id_set_contains(const struct btf *btf,
461 enum bpf_prog_type prog_type,
463 int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
464 const struct btf_kfunc_id_set *s);
465 s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id);
466 int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
467 struct module *owner);
468 struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id);
469 const struct btf_member *
470 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
471 const struct btf_type *t, enum bpf_prog_type prog_type,
473 bool btf_types_are_same(const struct btf *btf1, u32 id1,
474 const struct btf *btf2, u32 id2);
476 static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
481 static inline const char *btf_name_by_offset(const struct btf *btf,
486 static inline u32 *btf_kfunc_id_set_contains(const struct btf *btf,
487 enum bpf_prog_type prog_type,
492 static inline int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
493 const struct btf_kfunc_id_set *s)
497 static inline s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
501 static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors,
502 u32 add_cnt, struct module *owner)
506 static inline struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
510 static inline const struct btf_member *
511 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
512 const struct btf_type *t, enum bpf_prog_type prog_type,
517 static inline bool btf_types_are_same(const struct btf *btf1, u32 id1,
518 const struct btf *btf2, u32 id2)
524 static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
526 if (!btf_type_is_ptr(t))
529 t = btf_type_skip_modifiers(btf, t->type, NULL);
531 return btf_type_is_struct(t);