1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2 
3 /*
4  * Common eBPF ELF object loading operations.
5  *
6  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
7  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
8  * Copyright (C) 2015 Huawei Inc.
9  */
10 #ifndef __LIBBPF_LIBBPF_H
11 #define __LIBBPF_LIBBPF_H
12 
13 #include <stdarg.h>
14 #include <stdio.h>
15 #include <stdint.h>
16 #include <stdbool.h>
17 #include <sys/types.h>  // for size_t
18 #include <linux/bpf.h>
19 
20 #include "libbpf_common.h"
21 #include "libbpf_legacy.h"
22 
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
26 
27 LIBBPF_API __u32 libbpf_major_version(void);
28 LIBBPF_API __u32 libbpf_minor_version(void);
29 LIBBPF_API const char *libbpf_version_string(void);
30 
31 enum libbpf_errno {
32 	__LIBBPF_ERRNO__START = 4000,
33 
34 	/* Something wrong in libelf */
35 	LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START,
36 	LIBBPF_ERRNO__FORMAT,	/* BPF object format invalid */
37 	LIBBPF_ERRNO__KVERSION,	/* Incorrect or no 'version' section */
38 	LIBBPF_ERRNO__ENDIAN,	/* Endian mismatch */
39 	LIBBPF_ERRNO__INTERNAL,	/* Internal error in libbpf */
40 	LIBBPF_ERRNO__RELOC,	/* Relocation failed */
41 	LIBBPF_ERRNO__LOAD,	/* Load program failure for unknown reason */
42 	LIBBPF_ERRNO__VERIFY,	/* Kernel verifier blocks program loading */
43 	LIBBPF_ERRNO__PROG2BIG,	/* Program too big */
44 	LIBBPF_ERRNO__KVER,	/* Incorrect kernel version */
45 	LIBBPF_ERRNO__PROGTYPE,	/* Kernel doesn't support this program type */
46 	LIBBPF_ERRNO__WRNGPID,	/* Wrong pid in netlink message */
47 	LIBBPF_ERRNO__INVSEQ,	/* Invalid netlink sequence */
48 	LIBBPF_ERRNO__NLPARSE,	/* netlink parsing error */
49 	__LIBBPF_ERRNO__END,
50 };
51 
52 LIBBPF_API int libbpf_strerror(int err, char *buf, size_t size);
53 
54 /**
55  * @brief **libbpf_bpf_attach_type_str()** converts the provided attach type
56  * value into a textual representation.
57  * @param t The attach type.
58  * @return Pointer to a static string identifying the attach type. NULL is
59  * returned for unknown **bpf_attach_type** values.
60  */
61 LIBBPF_API const char *libbpf_bpf_attach_type_str(enum bpf_attach_type t);
62 
63 /**
64  * @brief **libbpf_bpf_link_type_str()** converts the provided link type value
65  * into a textual representation.
66  * @param t The link type.
67  * @return Pointer to a static string identifying the link type. NULL is
68  * returned for unknown **bpf_link_type** values.
69  */
70 LIBBPF_API const char *libbpf_bpf_link_type_str(enum bpf_link_type t);
71 
72 /**
73  * @brief **libbpf_bpf_map_type_str()** converts the provided map type value
74  * into a textual representation.
75  * @param t The map type.
76  * @return Pointer to a static string identifying the map type. NULL is
77  * returned for unknown **bpf_map_type** values.
78  */
79 LIBBPF_API const char *libbpf_bpf_map_type_str(enum bpf_map_type t);
80 
81 /**
82  * @brief **libbpf_bpf_prog_type_str()** converts the provided program type
83  * value into a textual representation.
84  * @param t The program type.
85  * @return Pointer to a static string identifying the program type. NULL is
86  * returned for unknown **bpf_prog_type** values.
87  */
88 LIBBPF_API const char *libbpf_bpf_prog_type_str(enum bpf_prog_type t);
89 
90 enum libbpf_print_level {
91         LIBBPF_WARN,
92         LIBBPF_INFO,
93         LIBBPF_DEBUG,
94 };
95 
96 typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level,
97 				 const char *, va_list ap);
98 
99 LIBBPF_API libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn);
100 
101 /* Hide internal to user */
102 struct bpf_object;
103 
104 struct bpf_object_open_opts {
105 	/* size of this struct, for forward/backward compatibility */
106 	size_t sz;
107 	/* object name override, if provided:
108 	 * - for object open from file, this will override setting object
109 	 *   name from file path's base name;
110 	 * - for object open from memory buffer, this will specify an object
111 	 *   name and will override default "<addr>-<buf-size>" name;
112 	 */
113 	const char *object_name;
114 	/* parse map definitions non-strictly, allowing extra attributes/data */
115 	bool relaxed_maps;
116 	/* maps that set the 'pinning' attribute in their definition will have
117 	 * their pin_path attribute set to a file in this directory, and be
118 	 * auto-pinned to that path on load; defaults to "/sys/fs/bpf".
119 	 */
120 	const char *pin_root_path;
121 
122 	__u32 :32; /* stub out now removed attach_prog_fd */
123 
124 	/* Additional kernel config content that augments and overrides
125 	 * system Kconfig for CONFIG_xxx externs.
126 	 */
127 	const char *kconfig;
128 	/* Path to the custom BTF to be used for BPF CO-RE relocations.
129 	 * This custom BTF completely replaces the use of vmlinux BTF
130 	 * for the purpose of CO-RE relocations.
131 	 * NOTE: any other BPF feature (e.g., fentry/fexit programs,
132 	 * struct_ops, etc) will need actual kernel BTF at /sys/kernel/btf/vmlinux.
133 	 */
134 	const char *btf_custom_path;
135 	/* Pointer to a buffer for storing kernel logs for applicable BPF
136 	 * commands. Valid kernel_log_size has to be specified as well and are
137 	 * passed-through to bpf() syscall. Keep in mind that kernel might
138 	 * fail operation with -ENOSPC error if provided buffer is too small
139 	 * to contain entire log output.
140 	 * See the comment below for kernel_log_level for interaction between
141 	 * log_buf and log_level settings.
142 	 *
143 	 * If specified, this log buffer will be passed for:
144 	 *   - each BPF progral load (BPF_PROG_LOAD) attempt, unless overriden
145 	 *     with bpf_program__set_log() on per-program level, to get
146 	 *     BPF verifier log output.
147 	 *   - during BPF object's BTF load into kernel (BPF_BTF_LOAD) to get
148 	 *     BTF sanity checking log.
149 	 *
150 	 * Each BPF command (BPF_BTF_LOAD or BPF_PROG_LOAD) will overwrite
151 	 * previous contents, so if you need more fine-grained control, set
152 	 * per-program buffer with bpf_program__set_log_buf() to preserve each
153 	 * individual program's verification log. Keep using kernel_log_buf
154 	 * for BTF verification log, if necessary.
155 	 */
156 	char *kernel_log_buf;
157 	size_t kernel_log_size;
158 	/*
159 	 * Log level can be set independently from log buffer. Log_level=0
160 	 * means that libbpf will attempt loading BTF or program without any
161 	 * logging requested, but will retry with either its own or custom log
162 	 * buffer, if provided, and log_level=1 on any error.
163 	 * And vice versa, setting log_level>0 will request BTF or prog
164 	 * loading with verbose log from the first attempt (and as such also
165 	 * for successfully loaded BTF or program), and the actual log buffer
166 	 * could be either libbpf's own auto-allocated log buffer, if
167 	 * kernel_log_buffer is NULL, or user-provided custom kernel_log_buf.
168 	 * If user didn't provide custom log buffer, libbpf will emit captured
169 	 * logs through its print callback.
170 	 */
171 	__u32 kernel_log_level;
172 
173 	size_t :0;
174 };
175 #define bpf_object_open_opts__last_field kernel_log_level
176 
177 LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
178 
179 /**
180  * @brief **bpf_object__open_file()** creates a bpf_object by opening
181  * the BPF ELF object file pointed to by the passed path and loading it
182  * into memory.
183  * @param path BPF object file path
184  * @param opts options for how to load the bpf object, this parameter is
185  * optional and can be set to NULL
186  * @return pointer to the new bpf_object; or NULL is returned on error,
187  * error code is stored in errno
188  */
189 LIBBPF_API struct bpf_object *
190 bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts);
191 
192 /**
193  * @brief **bpf_object__open_mem()** creates a bpf_object by reading
194  * the BPF objects raw bytes from a memory buffer containing a valid
195  * BPF ELF object file.
196  * @param obj_buf pointer to the buffer containing ELF file bytes
197  * @param obj_buf_sz number of bytes in the buffer
198  * @param opts options for how to load the bpf object
199  * @return pointer to the new bpf_object; or NULL is returned on error,
200  * error code is stored in errno
201  */
202 LIBBPF_API struct bpf_object *
203 bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
204 		     const struct bpf_object_open_opts *opts);
205 
206 /* Load/unload object into/from kernel */
207 LIBBPF_API int bpf_object__load(struct bpf_object *obj);
208 
209 LIBBPF_API void bpf_object__close(struct bpf_object *object);
210 
211 /* pin_maps and unpin_maps can both be called with a NULL path, in which case
212  * they will use the pin_path attribute of each map (and ignore all maps that
213  * don't have a pin_path set).
214  */
215 LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
216 LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
217 				      const char *path);
218 LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj,
219 					const char *path);
220 LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
221 					  const char *path);
222 LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
223 
224 LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);
225 LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);
226 LIBBPF_API int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version);
227 
228 struct btf;
229 LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj);
230 LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
231 
232 LIBBPF_API struct bpf_program *
233 bpf_object__find_program_by_name(const struct bpf_object *obj,
234 				 const char *name);
235 
236 LIBBPF_API int
237 libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
238 			 enum bpf_attach_type *expected_attach_type);
239 LIBBPF_API int libbpf_attach_type_by_name(const char *name,
240 					  enum bpf_attach_type *attach_type);
241 LIBBPF_API int libbpf_find_vmlinux_btf_id(const char *name,
242 					  enum bpf_attach_type attach_type);
243 
244 /* Accessors of bpf_program */
245 struct bpf_program;
246 
247 LIBBPF_API struct bpf_program *
248 bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prog);
249 
250 #define bpf_object__for_each_program(pos, obj)			\
251 	for ((pos) = bpf_object__next_program((obj), NULL);	\
252 	     (pos) != NULL;					\
253 	     (pos) = bpf_object__next_program((obj), (pos)))
254 
255 LIBBPF_API struct bpf_program *
256 bpf_object__prev_program(const struct bpf_object *obj, struct bpf_program *prog);
257 
258 LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,
259 					 __u32 ifindex);
260 
261 LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog);
262 LIBBPF_API const char *bpf_program__section_name(const struct bpf_program *prog);
263 LIBBPF_API bool bpf_program__autoload(const struct bpf_program *prog);
264 LIBBPF_API int bpf_program__set_autoload(struct bpf_program *prog, bool autoload);
265 LIBBPF_API bool bpf_program__autoattach(const struct bpf_program *prog);
266 LIBBPF_API void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach);
267 
268 struct bpf_insn;
269 
270 /**
271  * @brief **bpf_program__insns()** gives read-only access to BPF program's
272  * underlying BPF instructions.
273  * @param prog BPF program for which to return instructions
274  * @return a pointer to an array of BPF instructions that belong to the
275  * specified BPF program
276  *
277  * Returned pointer is always valid and not NULL. Number of `struct bpf_insn`
278  * pointed to can be fetched using **bpf_program__insn_cnt()** API.
279  *
280  * Keep in mind, libbpf can modify and append/delete BPF program's
281  * instructions as it processes BPF object file and prepares everything for
282  * uploading into the kernel. So depending on the point in BPF object
283  * lifetime, **bpf_program__insns()** can return different sets of
284  * instructions. As an example, during BPF object load phase BPF program
285  * instructions will be CO-RE-relocated, BPF subprograms instructions will be
286  * appended, ldimm64 instructions will have FDs embedded, etc. So instructions
287  * returned before **bpf_object__load()** and after it might be quite
288  * different.
289  */
290 LIBBPF_API const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog);
291 
292 /**
293  * @brief **bpf_program__set_insns()** can set BPF program's underlying
294  * BPF instructions.
295  *
296  * WARNING: This is a very advanced libbpf API and users need to know
297  * what they are doing. This should be used from prog_prepare_load_fn
298  * callback only.
299  *
300  * @param prog BPF program for which to return instructions
301  * @param new_insns a pointer to an array of BPF instructions
302  * @param new_insn_cnt number of `struct bpf_insn`'s that form
303  * specified BPF program
304  * @return 0, on success; negative error code, otherwise
305  */
306 LIBBPF_API int bpf_program__set_insns(struct bpf_program *prog,
307 				      struct bpf_insn *new_insns, size_t new_insn_cnt);
308 
309 /**
310  * @brief **bpf_program__insn_cnt()** returns number of `struct bpf_insn`'s
311  * that form specified BPF program.
312  * @param prog BPF program for which to return number of BPF instructions
313  *
314  * See **bpf_program__insns()** documentation for notes on how libbpf can
315  * change instructions and their count during different phases of
316  * **bpf_object** lifetime.
317  */
318 LIBBPF_API size_t bpf_program__insn_cnt(const struct bpf_program *prog);
319 
320 LIBBPF_API int bpf_program__fd(const struct bpf_program *prog);
321 
322 /**
323  * @brief **bpf_program__pin()** pins the BPF program to a file
324  * in the BPF FS specified by a path. This increments the programs
325  * reference count, allowing it to stay loaded after the process
326  * which loaded it has exited.
327  *
328  * @param prog BPF program to pin, must already be loaded
329  * @param path file path in a BPF file system
330  * @return 0, on success; negative error code, otherwise
331  */
332 LIBBPF_API int bpf_program__pin(struct bpf_program *prog, const char *path);
333 
334 /**
335  * @brief **bpf_program__unpin()** unpins the BPF program from a file
336  * in the BPFFS specified by a path. This decrements the programs
337  * reference count.
338  *
339  * The file pinning the BPF program can also be unlinked by a different
340  * process in which case this function will return an error.
341  *
342  * @param prog BPF program to unpin
343  * @param path file path to the pin in a BPF file system
344  * @return 0, on success; negative error code, otherwise
345  */
346 LIBBPF_API int bpf_program__unpin(struct bpf_program *prog, const char *path);
347 LIBBPF_API void bpf_program__unload(struct bpf_program *prog);
348 
349 struct bpf_link;
350 
351 LIBBPF_API struct bpf_link *bpf_link__open(const char *path);
352 LIBBPF_API int bpf_link__fd(const struct bpf_link *link);
353 LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link);
354 /**
355  * @brief **bpf_link__pin()** pins the BPF link to a file
356  * in the BPF FS specified by a path. This increments the links
357  * reference count, allowing it to stay loaded after the process
358  * which loaded it has exited.
359  *
360  * @param link BPF link to pin, must already be loaded
361  * @param path file path in a BPF file system
362  * @return 0, on success; negative error code, otherwise
363  */
364 
365 LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path);
366 
367 /**
368  * @brief **bpf_link__unpin()** unpins the BPF link from a file
369  * in the BPFFS specified by a path. This decrements the links
370  * reference count.
371  *
372  * The file pinning the BPF link can also be unlinked by a different
373  * process in which case this function will return an error.
374  *
375  * @param prog BPF program to unpin
376  * @param path file path to the pin in a BPF file system
377  * @return 0, on success; negative error code, otherwise
378  */
379 LIBBPF_API int bpf_link__unpin(struct bpf_link *link);
380 LIBBPF_API int bpf_link__update_program(struct bpf_link *link,
381 					struct bpf_program *prog);
382 LIBBPF_API void bpf_link__disconnect(struct bpf_link *link);
383 LIBBPF_API int bpf_link__detach(struct bpf_link *link);
384 LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
385 
386 /**
387  * @brief **bpf_program__attach()** is a generic function for attaching
388  * a BPF program based on auto-detection of program type, attach type,
389  * and extra paremeters, where applicable.
390  *
391  * @param prog BPF program to attach
392  * @return Reference to the newly created BPF link; or NULL is returned on error,
393  * error code is stored in errno
394  *
395  * This is supported for:
396  *   - kprobe/kretprobe (depends on SEC() definition)
397  *   - uprobe/uretprobe (depends on SEC() definition)
398  *   - tracepoint
399  *   - raw tracepoint
400  *   - tracing programs (typed raw TP/fentry/fexit/fmod_ret)
401  */
402 LIBBPF_API struct bpf_link *
403 bpf_program__attach(const struct bpf_program *prog);
404 
405 struct bpf_perf_event_opts {
406 	/* size of this struct, for forward/backward compatiblity */
407 	size_t sz;
408 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
409 	__u64 bpf_cookie;
410 };
411 #define bpf_perf_event_opts__last_field bpf_cookie
412 
413 LIBBPF_API struct bpf_link *
414 bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd);
415 
416 LIBBPF_API struct bpf_link *
417 bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd,
418 				    const struct bpf_perf_event_opts *opts);
419 
420 struct bpf_kprobe_opts {
421 	/* size of this struct, for forward/backward compatiblity */
422 	size_t sz;
423 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
424 	__u64 bpf_cookie;
425 	/* function's offset to install kprobe to */
426 	size_t offset;
427 	/* kprobe is return probe */
428 	bool retprobe;
429 	size_t :0;
430 };
431 #define bpf_kprobe_opts__last_field retprobe
432 
433 LIBBPF_API struct bpf_link *
434 bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe,
435 			   const char *func_name);
436 LIBBPF_API struct bpf_link *
437 bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
438                                 const char *func_name,
439                                 const struct bpf_kprobe_opts *opts);
440 
441 struct bpf_kprobe_multi_opts {
442 	/* size of this struct, for forward/backward compatibility */
443 	size_t sz;
444 	/* array of function symbols to attach */
445 	const char **syms;
446 	/* array of function addresses to attach */
447 	const unsigned long *addrs;
448 	/* array of user-provided values fetchable through bpf_get_attach_cookie */
449 	const __u64 *cookies;
450 	/* number of elements in syms/addrs/cookies arrays */
451 	size_t cnt;
452 	/* create return kprobes */
453 	bool retprobe;
454 	size_t :0;
455 };
456 
457 #define bpf_kprobe_multi_opts__last_field retprobe
458 
459 LIBBPF_API struct bpf_link *
460 bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
461 				      const char *pattern,
462 				      const struct bpf_kprobe_multi_opts *opts);
463 
464 struct bpf_ksyscall_opts {
465 	/* size of this struct, for forward/backward compatiblity */
466 	size_t sz;
467 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
468 	__u64 bpf_cookie;
469 	/* attach as return probe? */
470 	bool retprobe;
471 	size_t :0;
472 };
473 #define bpf_ksyscall_opts__last_field retprobe
474 
475 /**
476  * @brief **bpf_program__attach_ksyscall()** attaches a BPF program
477  * to kernel syscall handler of a specified syscall. Optionally it's possible
478  * to request to install retprobe that will be triggered at syscall exit. It's
479  * also possible to associate BPF cookie (though options).
480  *
481  * Libbpf automatically will determine correct full kernel function name,
482  * which depending on system architecture and kernel version/configuration
483  * could be of the form __<arch>_sys_<syscall> or __se_sys_<syscall>, and will
484  * attach specified program using kprobe/kretprobe mechanism.
485  *
486  * **bpf_program__attach_ksyscall()** is an API counterpart of declarative
487  * **SEC("ksyscall/<syscall>")** annotation of BPF programs.
488  *
489  * At the moment **SEC("ksyscall")** and **bpf_program__attach_ksyscall()** do
490  * not handle all the calling convention quirks for mmap(), clone() and compat
491  * syscalls. It also only attaches to "native" syscall interfaces. If host
492  * system supports compat syscalls or defines 32-bit syscalls in 64-bit
493  * kernel, such syscall interfaces won't be attached to by libbpf.
494  *
495  * These limitations may or may not change in the future. Therefore it is
496  * recommended to use SEC("kprobe") for these syscalls or if working with
497  * compat and 32-bit interfaces is required.
498  *
499  * @param prog BPF program to attach
500  * @param syscall_name Symbolic name of the syscall (e.g., "bpf")
501  * @param opts Additional options (see **struct bpf_ksyscall_opts**)
502  * @return Reference to the newly created BPF link; or NULL is returned on
503  * error, error code is stored in errno
504  */
505 LIBBPF_API struct bpf_link *
506 bpf_program__attach_ksyscall(const struct bpf_program *prog,
507 			     const char *syscall_name,
508 			     const struct bpf_ksyscall_opts *opts);
509 
510 struct bpf_uprobe_opts {
511 	/* size of this struct, for forward/backward compatiblity */
512 	size_t sz;
513 	/* offset of kernel reference counted USDT semaphore, added in
514 	 * a6ca88b241d5 ("trace_uprobe: support reference counter in fd-based uprobe")
515 	 */
516 	size_t ref_ctr_offset;
517 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
518 	__u64 bpf_cookie;
519 	/* uprobe is return probe, invoked at function return time */
520 	bool retprobe;
521 	/* Function name to attach to.  Could be an unqualified ("abc") or library-qualified
522 	 * "abc@LIBXYZ" name.  To specify function entry, func_name should be set while
523 	 * func_offset argument to bpf_prog__attach_uprobe_opts() should be 0.  To trace an
524 	 * offset within a function, specify func_name and use func_offset argument to specify
525 	 * offset within the function.  Shared library functions must specify the shared library
526 	 * binary_path.
527 	 */
528 	const char *func_name;
529 	size_t :0;
530 };
531 #define bpf_uprobe_opts__last_field func_name
532 
533 /**
534  * @brief **bpf_program__attach_uprobe()** attaches a BPF program
535  * to the userspace function which is found by binary path and
536  * offset. You can optionally specify a particular proccess to attach
537  * to. You can also optionally attach the program to the function
538  * exit instead of entry.
539  *
540  * @param prog BPF program to attach
541  * @param retprobe Attach to function exit
542  * @param pid Process ID to attach the uprobe to, 0 for self (own process),
543  * -1 for all processes
544  * @param binary_path Path to binary that contains the function symbol
545  * @param func_offset Offset within the binary of the function symbol
546  * @return Reference to the newly created BPF link; or NULL is returned on error,
547  * error code is stored in errno
548  */
549 LIBBPF_API struct bpf_link *
550 bpf_program__attach_uprobe(const struct bpf_program *prog, bool retprobe,
551 			   pid_t pid, const char *binary_path,
552 			   size_t func_offset);
553 
554 /**
555  * @brief **bpf_program__attach_uprobe_opts()** is just like
556  * bpf_program__attach_uprobe() except with a options struct
557  * for various configurations.
558  *
559  * @param prog BPF program to attach
560  * @param pid Process ID to attach the uprobe to, 0 for self (own process),
561  * -1 for all processes
562  * @param binary_path Path to binary that contains the function symbol
563  * @param func_offset Offset within the binary of the function symbol
564  * @param opts Options for altering program attachment
565  * @return Reference to the newly created BPF link; or NULL is returned on error,
566  * error code is stored in errno
567  */
568 LIBBPF_API struct bpf_link *
569 bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
570 				const char *binary_path, size_t func_offset,
571 				const struct bpf_uprobe_opts *opts);
572 
573 struct bpf_usdt_opts {
574 	/* size of this struct, for forward/backward compatibility */
575 	size_t sz;
576 	/* custom user-provided value accessible through usdt_cookie() */
577 	__u64 usdt_cookie;
578 	size_t :0;
579 };
580 #define bpf_usdt_opts__last_field usdt_cookie
581 
582 /**
583  * @brief **bpf_program__attach_usdt()** is just like
584  * bpf_program__attach_uprobe_opts() except it covers USDT (User-space
585  * Statically Defined Tracepoint) attachment, instead of attaching to
586  * user-space function entry or exit.
587  *
588  * @param prog BPF program to attach
589  * @param pid Process ID to attach the uprobe to, 0 for self (own process),
590  * -1 for all processes
591  * @param binary_path Path to binary that contains provided USDT probe
592  * @param usdt_provider USDT provider name
593  * @param usdt_name USDT probe name
594  * @param opts Options for altering program attachment
595  * @return Reference to the newly created BPF link; or NULL is returned on error,
596  * error code is stored in errno
597  */
598 LIBBPF_API struct bpf_link *
599 bpf_program__attach_usdt(const struct bpf_program *prog,
600 			 pid_t pid, const char *binary_path,
601 			 const char *usdt_provider, const char *usdt_name,
602 			 const struct bpf_usdt_opts *opts);
603 
604 struct bpf_tracepoint_opts {
605 	/* size of this struct, for forward/backward compatiblity */
606 	size_t sz;
607 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
608 	__u64 bpf_cookie;
609 };
610 #define bpf_tracepoint_opts__last_field bpf_cookie
611 
612 LIBBPF_API struct bpf_link *
613 bpf_program__attach_tracepoint(const struct bpf_program *prog,
614 			       const char *tp_category,
615 			       const char *tp_name);
616 LIBBPF_API struct bpf_link *
617 bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
618 				    const char *tp_category,
619 				    const char *tp_name,
620 				    const struct bpf_tracepoint_opts *opts);
621 
622 LIBBPF_API struct bpf_link *
623 bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
624 				   const char *tp_name);
625 
626 struct bpf_trace_opts {
627 	/* size of this struct, for forward/backward compatibility */
628 	size_t sz;
629 	/* custom user-provided value fetchable through bpf_get_attach_cookie() */
630 	__u64 cookie;
631 };
632 #define bpf_trace_opts__last_field cookie
633 
634 LIBBPF_API struct bpf_link *
635 bpf_program__attach_trace(const struct bpf_program *prog);
636 LIBBPF_API struct bpf_link *
637 bpf_program__attach_trace_opts(const struct bpf_program *prog, const struct bpf_trace_opts *opts);
638 
639 LIBBPF_API struct bpf_link *
640 bpf_program__attach_lsm(const struct bpf_program *prog);
641 LIBBPF_API struct bpf_link *
642 bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd);
643 LIBBPF_API struct bpf_link *
644 bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd);
645 LIBBPF_API struct bpf_link *
646 bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex);
647 LIBBPF_API struct bpf_link *
648 bpf_program__attach_freplace(const struct bpf_program *prog,
649 			     int target_fd, const char *attach_func_name);
650 
651 struct bpf_map;
652 
653 LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);
654 
655 struct bpf_iter_attach_opts {
656 	size_t sz; /* size of this struct for forward/backward compatibility */
657 	union bpf_iter_link_info *link_info;
658 	__u32 link_info_len;
659 };
660 #define bpf_iter_attach_opts__last_field link_info_len
661 
662 LIBBPF_API struct bpf_link *
663 bpf_program__attach_iter(const struct bpf_program *prog,
664 			 const struct bpf_iter_attach_opts *opts);
665 
666 LIBBPF_API enum bpf_prog_type bpf_program__type(const struct bpf_program *prog);
667 
668 /**
669  * @brief **bpf_program__set_type()** sets the program
670  * type of the passed BPF program.
671  * @param prog BPF program to set the program type for
672  * @param type program type to set the BPF map to have
673  * @return error code; or 0 if no error. An error occurs
674  * if the object is already loaded.
675  *
676  * This must be called before the BPF object is loaded,
677  * otherwise it has no effect and an error is returned.
678  */
679 LIBBPF_API int bpf_program__set_type(struct bpf_program *prog,
680 				     enum bpf_prog_type type);
681 
682 LIBBPF_API enum bpf_attach_type
683 bpf_program__expected_attach_type(const struct bpf_program *prog);
684 
685 /**
686  * @brief **bpf_program__set_expected_attach_type()** sets the
687  * attach type of the passed BPF program. This is used for
688  * auto-detection of attachment when programs are loaded.
689  * @param prog BPF program to set the attach type for
690  * @param type attach type to set the BPF map to have
691  * @return error code; or 0 if no error. An error occurs
692  * if the object is already loaded.
693  *
694  * This must be called before the BPF object is loaded,
695  * otherwise it has no effect and an error is returned.
696  */
697 LIBBPF_API int
698 bpf_program__set_expected_attach_type(struct bpf_program *prog,
699 				      enum bpf_attach_type type);
700 
701 LIBBPF_API __u32 bpf_program__flags(const struct bpf_program *prog);
702 LIBBPF_API int bpf_program__set_flags(struct bpf_program *prog, __u32 flags);
703 
704 /* Per-program log level and log buffer getters/setters.
705  * See bpf_object_open_opts comments regarding log_level and log_buf
706  * interactions.
707  */
708 LIBBPF_API __u32 bpf_program__log_level(const struct bpf_program *prog);
709 LIBBPF_API int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level);
710 LIBBPF_API const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size);
711 LIBBPF_API int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size);
712 
713 /**
714  * @brief **bpf_program__set_attach_target()** sets BTF-based attach target
715  * for supported BPF program types:
716  *   - BTF-aware raw tracepoints (tp_btf);
717  *   - fentry/fexit/fmod_ret;
718  *   - lsm;
719  *   - freplace.
720  * @param prog BPF program to set the attach type for
721  * @param type attach type to set the BPF map to have
722  * @return error code; or 0 if no error occurred.
723  */
724 LIBBPF_API int
725 bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd,
726 			       const char *attach_func_name);
727 
728 /**
729  * @brief **bpf_object__find_map_by_name()** returns BPF map of
730  * the given name, if it exists within the passed BPF object
731  * @param obj BPF object
732  * @param name name of the BPF map
733  * @return BPF map instance, if such map exists within the BPF object;
734  * or NULL otherwise.
735  */
736 LIBBPF_API struct bpf_map *
737 bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name);
738 
739 LIBBPF_API int
740 bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name);
741 
742 LIBBPF_API struct bpf_map *
743 bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *map);
744 
745 #define bpf_object__for_each_map(pos, obj)		\
746 	for ((pos) = bpf_object__next_map((obj), NULL);	\
747 	     (pos) != NULL;				\
748 	     (pos) = bpf_object__next_map((obj), (pos)))
749 #define bpf_map__for_each bpf_object__for_each_map
750 
751 LIBBPF_API struct bpf_map *
752 bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *map);
753 
754 /**
755  * @brief **bpf_map__set_autocreate()** sets whether libbpf has to auto-create
756  * BPF map during BPF object load phase.
757  * @param map the BPF map instance
758  * @param autocreate whether to create BPF map during BPF object load
759  * @return 0 on success; -EBUSY if BPF object was already loaded
760  *
761  * **bpf_map__set_autocreate()** allows to opt-out from libbpf auto-creating
762  * BPF map. By default, libbpf will attempt to create every single BPF map
763  * defined in BPF object file using BPF_MAP_CREATE command of bpf() syscall
764  * and fill in map FD in BPF instructions.
765  *
766  * This API allows to opt-out of this process for specific map instance. This
767  * can be useful if host kernel doesn't support such BPF map type or used
768  * combination of flags and user application wants to avoid creating such
769  * a map in the first place. User is still responsible to make sure that their
770  * BPF-side code that expects to use such missing BPF map is recognized by BPF
771  * verifier as dead code, otherwise BPF verifier will reject such BPF program.
772  */
773 LIBBPF_API int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate);
774 LIBBPF_API bool bpf_map__autocreate(const struct bpf_map *map);
775 
776 /**
777  * @brief **bpf_map__fd()** gets the file descriptor of the passed
778  * BPF map
779  * @param map the BPF map instance
780  * @return the file descriptor; or -EINVAL in case of an error
781  */
782 LIBBPF_API int bpf_map__fd(const struct bpf_map *map);
783 LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
784 /* get map name */
785 LIBBPF_API const char *bpf_map__name(const struct bpf_map *map);
786 /* get/set map type */
787 LIBBPF_API enum bpf_map_type bpf_map__type(const struct bpf_map *map);
788 LIBBPF_API int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type);
789 /* get/set map size (max_entries) */
790 LIBBPF_API __u32 bpf_map__max_entries(const struct bpf_map *map);
791 LIBBPF_API int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries);
792 /* get/set map flags */
793 LIBBPF_API __u32 bpf_map__map_flags(const struct bpf_map *map);
794 LIBBPF_API int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags);
795 /* get/set map NUMA node */
796 LIBBPF_API __u32 bpf_map__numa_node(const struct bpf_map *map);
797 LIBBPF_API int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node);
798 /* get/set map key size */
799 LIBBPF_API __u32 bpf_map__key_size(const struct bpf_map *map);
800 LIBBPF_API int bpf_map__set_key_size(struct bpf_map *map, __u32 size);
801 /* get/set map value size */
802 LIBBPF_API __u32 bpf_map__value_size(const struct bpf_map *map);
803 LIBBPF_API int bpf_map__set_value_size(struct bpf_map *map, __u32 size);
804 /* get map key/value BTF type IDs */
805 LIBBPF_API __u32 bpf_map__btf_key_type_id(const struct bpf_map *map);
806 LIBBPF_API __u32 bpf_map__btf_value_type_id(const struct bpf_map *map);
807 /* get/set map if_index */
808 LIBBPF_API __u32 bpf_map__ifindex(const struct bpf_map *map);
809 LIBBPF_API int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
810 /* get/set map map_extra flags */
811 LIBBPF_API __u64 bpf_map__map_extra(const struct bpf_map *map);
812 LIBBPF_API int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra);
813 
814 LIBBPF_API int bpf_map__set_initial_value(struct bpf_map *map,
815 					  const void *data, size_t size);
816 LIBBPF_API const void *bpf_map__initial_value(struct bpf_map *map, size_t *psize);
817 
818 /**
819  * @brief **bpf_map__is_internal()** tells the caller whether or not the
820  * passed map is a special map created by libbpf automatically for things like
821  * global variables, __ksym externs, Kconfig values, etc
822  * @param map the bpf_map
823  * @return true, if the map is an internal map; false, otherwise
824  */
825 LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
826 LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path);
827 LIBBPF_API const char *bpf_map__pin_path(const struct bpf_map *map);
828 LIBBPF_API bool bpf_map__is_pinned(const struct bpf_map *map);
829 LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
830 LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
831 
832 LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd);
833 LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map);
834 
835 /**
836  * @brief **bpf_map__lookup_elem()** allows to lookup BPF map value
837  * corresponding to provided key.
838  * @param map BPF map to lookup element in
839  * @param key pointer to memory containing bytes of the key used for lookup
840  * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
841  * @param value pointer to memory in which looked up value will be stored
842  * @param value_sz size in byte of value data memory; it has to match BPF map
843  * definition's **value_size**. For per-CPU BPF maps value size has to be
844  * a product of BPF map value size and number of possible CPUs in the system
845  * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for
846  * per-CPU values value size has to be aligned up to closest 8 bytes for
847  * alignment reasons, so expected size is: `round_up(value_size, 8)
848  * * libbpf_num_possible_cpus()`.
849  * @flags extra flags passed to kernel for this operation
850  * @return 0, on success; negative error, otherwise
851  *
852  * **bpf_map__lookup_elem()** is high-level equivalent of
853  * **bpf_map_lookup_elem()** API with added check for key and value size.
854  */
855 LIBBPF_API int bpf_map__lookup_elem(const struct bpf_map *map,
856 				    const void *key, size_t key_sz,
857 				    void *value, size_t value_sz, __u64 flags);
858 
859 /**
860  * @brief **bpf_map__update_elem()** allows to insert or update value in BPF
861  * map that corresponds to provided key.
862  * @param map BPF map to insert to or update element in
863  * @param key pointer to memory containing bytes of the key
864  * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
865  * @param value pointer to memory containing bytes of the value
866  * @param value_sz size in byte of value data memory; it has to match BPF map
867  * definition's **value_size**. For per-CPU BPF maps value size has to be
868  * a product of BPF map value size and number of possible CPUs in the system
869  * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for
870  * per-CPU values value size has to be aligned up to closest 8 bytes for
871  * alignment reasons, so expected size is: `round_up(value_size, 8)
872  * * libbpf_num_possible_cpus()`.
873  * @flags extra flags passed to kernel for this operation
874  * @return 0, on success; negative error, otherwise
875  *
876  * **bpf_map__update_elem()** is high-level equivalent of
877  * **bpf_map_update_elem()** API with added check for key and value size.
878  */
879 LIBBPF_API int bpf_map__update_elem(const struct bpf_map *map,
880 				    const void *key, size_t key_sz,
881 				    const void *value, size_t value_sz, __u64 flags);
882 
883 /**
884  * @brief **bpf_map__delete_elem()** allows to delete element in BPF map that
885  * corresponds to provided key.
886  * @param map BPF map to delete element from
887  * @param key pointer to memory containing bytes of the key
888  * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
889  * @flags extra flags passed to kernel for this operation
890  * @return 0, on success; negative error, otherwise
891  *
892  * **bpf_map__delete_elem()** is high-level equivalent of
893  * **bpf_map_delete_elem()** API with added check for key size.
894  */
895 LIBBPF_API int bpf_map__delete_elem(const struct bpf_map *map,
896 				    const void *key, size_t key_sz, __u64 flags);
897 
898 /**
899  * @brief **bpf_map__lookup_and_delete_elem()** allows to lookup BPF map value
900  * corresponding to provided key and atomically delete it afterwards.
901  * @param map BPF map to lookup element in
902  * @param key pointer to memory containing bytes of the key used for lookup
903  * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
904  * @param value pointer to memory in which looked up value will be stored
905  * @param value_sz size in byte of value data memory; it has to match BPF map
906  * definition's **value_size**. For per-CPU BPF maps value size has to be
907  * a product of BPF map value size and number of possible CPUs in the system
908  * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for
909  * per-CPU values value size has to be aligned up to closest 8 bytes for
910  * alignment reasons, so expected size is: `round_up(value_size, 8)
911  * * libbpf_num_possible_cpus()`.
912  * @flags extra flags passed to kernel for this operation
913  * @return 0, on success; negative error, otherwise
914  *
915  * **bpf_map__lookup_and_delete_elem()** is high-level equivalent of
916  * **bpf_map_lookup_and_delete_elem()** API with added check for key and value size.
917  */
918 LIBBPF_API int bpf_map__lookup_and_delete_elem(const struct bpf_map *map,
919 					       const void *key, size_t key_sz,
920 					       void *value, size_t value_sz, __u64 flags);
921 
922 /**
923  * @brief **bpf_map__get_next_key()** allows to iterate BPF map keys by
924  * fetching next key that follows current key.
925  * @param map BPF map to fetch next key from
926  * @param cur_key pointer to memory containing bytes of current key or NULL to
927  * fetch the first key
928  * @param next_key pointer to memory to write next key into
929  * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size**
930  * @return 0, on success; -ENOENT if **cur_key** is the last key in BPF map;
931  * negative error, otherwise
932  *
933  * **bpf_map__get_next_key()** is high-level equivalent of
934  * **bpf_map_get_next_key()** API with added check for key size.
935  */
936 LIBBPF_API int bpf_map__get_next_key(const struct bpf_map *map,
937 				     const void *cur_key, void *next_key, size_t key_sz);
938 
939 struct bpf_xdp_set_link_opts {
940 	size_t sz;
941 	int old_fd;
942 	size_t :0;
943 };
944 #define bpf_xdp_set_link_opts__last_field old_fd
945 
946 struct bpf_xdp_attach_opts {
947 	size_t sz;
948 	int old_prog_fd;
949 	size_t :0;
950 };
951 #define bpf_xdp_attach_opts__last_field old_prog_fd
952 
953 struct bpf_xdp_query_opts {
954 	size_t sz;
955 	__u32 prog_id;		/* output */
956 	__u32 drv_prog_id;	/* output */
957 	__u32 hw_prog_id;	/* output */
958 	__u32 skb_prog_id;	/* output */
959 	__u8 attach_mode;	/* output */
960 	size_t :0;
961 };
962 #define bpf_xdp_query_opts__last_field attach_mode
963 
964 LIBBPF_API int bpf_xdp_attach(int ifindex, int prog_fd, __u32 flags,
965 			      const struct bpf_xdp_attach_opts *opts);
966 LIBBPF_API int bpf_xdp_detach(int ifindex, __u32 flags,
967 			      const struct bpf_xdp_attach_opts *opts);
968 LIBBPF_API int bpf_xdp_query(int ifindex, int flags, struct bpf_xdp_query_opts *opts);
969 LIBBPF_API int bpf_xdp_query_id(int ifindex, int flags, __u32 *prog_id);
970 
971 /* TC related API */
972 enum bpf_tc_attach_point {
973 	BPF_TC_INGRESS = 1 << 0,
974 	BPF_TC_EGRESS  = 1 << 1,
975 	BPF_TC_CUSTOM  = 1 << 2,
976 };
977 
978 #define BPF_TC_PARENT(a, b) 	\
979 	((((a) << 16) & 0xFFFF0000U) | ((b) & 0x0000FFFFU))
980 
981 enum bpf_tc_flags {
982 	BPF_TC_F_REPLACE = 1 << 0,
983 };
984 
985 struct bpf_tc_hook {
986 	size_t sz;
987 	int ifindex;
988 	enum bpf_tc_attach_point attach_point;
989 	__u32 parent;
990 	size_t :0;
991 };
992 #define bpf_tc_hook__last_field parent
993 
994 struct bpf_tc_opts {
995 	size_t sz;
996 	int prog_fd;
997 	__u32 flags;
998 	__u32 prog_id;
999 	__u32 handle;
1000 	__u32 priority;
1001 	size_t :0;
1002 };
1003 #define bpf_tc_opts__last_field priority
1004 
1005 LIBBPF_API int bpf_tc_hook_create(struct bpf_tc_hook *hook);
1006 LIBBPF_API int bpf_tc_hook_destroy(struct bpf_tc_hook *hook);
1007 LIBBPF_API int bpf_tc_attach(const struct bpf_tc_hook *hook,
1008 			     struct bpf_tc_opts *opts);
1009 LIBBPF_API int bpf_tc_detach(const struct bpf_tc_hook *hook,
1010 			     const struct bpf_tc_opts *opts);
1011 LIBBPF_API int bpf_tc_query(const struct bpf_tc_hook *hook,
1012 			    struct bpf_tc_opts *opts);
1013 
1014 /* Ring buffer APIs */
1015 struct ring_buffer;
1016 struct user_ring_buffer;
1017 
1018 typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size);
1019 
1020 struct ring_buffer_opts {
1021 	size_t sz; /* size of this struct, for forward/backward compatiblity */
1022 };
1023 
1024 #define ring_buffer_opts__last_field sz
1025 
1026 LIBBPF_API struct ring_buffer *
1027 ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx,
1028 		 const struct ring_buffer_opts *opts);
1029 LIBBPF_API void ring_buffer__free(struct ring_buffer *rb);
1030 LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
1031 				ring_buffer_sample_fn sample_cb, void *ctx);
1032 LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
1033 LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
1034 LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
1035 
1036 struct user_ring_buffer_opts {
1037 	size_t sz; /* size of this struct, for forward/backward compatibility */
1038 };
1039 
1040 #define user_ring_buffer_opts__last_field sz
1041 
1042 /* @brief **user_ring_buffer__new()** creates a new instance of a user ring
1043  * buffer.
1044  *
1045  * @param map_fd A file descriptor to a BPF_MAP_TYPE_USER_RINGBUF map.
1046  * @param opts Options for how the ring buffer should be created.
1047  * @return A user ring buffer on success; NULL and errno being set on a
1048  * failure.
1049  */
1050 LIBBPF_API struct user_ring_buffer *
1051 user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts);
1052 
1053 /* @brief **user_ring_buffer__reserve()** reserves a pointer to a sample in the
1054  * user ring buffer.
1055  * @param rb A pointer to a user ring buffer.
1056  * @param size The size of the sample, in bytes.
1057  * @return A pointer to an 8-byte aligned reserved region of the user ring
1058  * buffer; NULL, and errno being set if a sample could not be reserved.
1059  *
1060  * This function is *not* thread safe, and callers must synchronize accessing
1061  * this function if there are multiple producers.  If a size is requested that
1062  * is larger than the size of the entire ring buffer, errno will be set to
1063  * E2BIG and NULL is returned. If the ring buffer could accommodate the size,
1064  * but currently does not have enough space, errno is set to ENOSPC and NULL is
1065  * returned.
1066  *
1067  * After initializing the sample, callers must invoke
1068  * **user_ring_buffer__submit()** to post the sample to the kernel. Otherwise,
1069  * the sample must be freed with **user_ring_buffer__discard()**.
1070  */
1071 LIBBPF_API void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
1072 
1073 /* @brief **user_ring_buffer__reserve_blocking()** reserves a record in the
1074  * ring buffer, possibly blocking for up to @timeout_ms until a sample becomes
1075  * available.
1076  * @param rb The user ring buffer.
1077  * @param size The size of the sample, in bytes.
1078  * @param timeout_ms The amount of time, in milliseconds, for which the caller
1079  * should block when waiting for a sample. -1 causes the caller to block
1080  * indefinitely.
1081  * @return A pointer to an 8-byte aligned reserved region of the user ring
1082  * buffer; NULL, and errno being set if a sample could not be reserved.
1083  *
1084  * This function is *not* thread safe, and callers must synchronize
1085  * accessing this function if there are multiple producers
1086  *
1087  * If **timeout_ms** is -1, the function will block indefinitely until a sample
1088  * becomes available. Otherwise, **timeout_ms** must be non-negative, or errno
1089  * is set to EINVAL, and NULL is returned. If **timeout_ms** is 0, no blocking
1090  * will occur and the function will return immediately after attempting to
1091  * reserve a sample.
1092  *
1093  * If **size** is larger than the size of the entire ring buffer, errno is set
1094  * to E2BIG and NULL is returned. If the ring buffer could accommodate
1095  * **size**, but currently does not have enough space, the caller will block
1096  * until at most **timeout_ms** has elapsed. If insufficient space is available
1097  * at that time, errno is set to ENOSPC, and NULL is returned.
1098  *
1099  * The kernel guarantees that it will wake up this thread to check if
1100  * sufficient space is available in the ring buffer at least once per
1101  * invocation of the **bpf_ringbuf_drain()** helper function, provided that at
1102  * least one sample is consumed, and the BPF program did not invoke the
1103  * function with BPF_RB_NO_WAKEUP. A wakeup may occur sooner than that, but the
1104  * kernel does not guarantee this. If the helper function is invoked with
1105  * BPF_RB_FORCE_WAKEUP, a wakeup event will be sent even if no sample is
1106  * consumed.
1107  *
1108  * When a sample of size **size** is found within **timeout_ms**, a pointer to
1109  * the sample is returned. After initializing the sample, callers must invoke
1110  * **user_ring_buffer__submit()** to post the sample to the ring buffer.
1111  * Otherwise, the sample must be freed with **user_ring_buffer__discard()**.
1112  */
1113 LIBBPF_API void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
1114 						    __u32 size,
1115 						    int timeout_ms);
1116 
1117 /* @brief **user_ring_buffer__submit()** submits a previously reserved sample
1118  * into the ring buffer.
1119  * @param rb The user ring buffer.
1120  * @param sample A reserved sample.
1121  *
1122  * It is not necessary to synchronize amongst multiple producers when invoking
1123  * this function.
1124  */
1125 LIBBPF_API void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
1126 
1127 /* @brief **user_ring_buffer__discard()** discards a previously reserved sample.
1128  * @param rb The user ring buffer.
1129  * @param sample A reserved sample.
1130  *
1131  * It is not necessary to synchronize amongst multiple producers when invoking
1132  * this function.
1133  */
1134 LIBBPF_API void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample);
1135 
1136 /* @brief **user_ring_buffer__free()** frees a ring buffer that was previously
1137  * created with **user_ring_buffer__new()**.
1138  * @param rb The user ring buffer being freed.
1139  */
1140 LIBBPF_API void user_ring_buffer__free(struct user_ring_buffer *rb);
1141 
1142 /* Perf buffer APIs */
1143 struct perf_buffer;
1144 
1145 typedef void (*perf_buffer_sample_fn)(void *ctx, int cpu,
1146 				      void *data, __u32 size);
1147 typedef void (*perf_buffer_lost_fn)(void *ctx, int cpu, __u64 cnt);
1148 
1149 /* common use perf buffer options */
1150 struct perf_buffer_opts {
1151 	size_t sz;
1152 };
1153 #define perf_buffer_opts__last_field sz
1154 
1155 /**
1156  * @brief **perf_buffer__new()** creates BPF perfbuf manager for a specified
1157  * BPF_PERF_EVENT_ARRAY map
1158  * @param map_fd FD of BPF_PERF_EVENT_ARRAY BPF map that will be used by BPF
1159  * code to send data over to user-space
1160  * @param page_cnt number of memory pages allocated for each per-CPU buffer
1161  * @param sample_cb function called on each received data record
1162  * @param lost_cb function called when record loss has occurred
1163  * @param ctx user-provided extra context passed into *sample_cb* and *lost_cb*
1164  * @return a new instance of struct perf_buffer on success, NULL on error with
1165  * *errno* containing an error code
1166  */
1167 LIBBPF_API struct perf_buffer *
1168 perf_buffer__new(int map_fd, size_t page_cnt,
1169 		 perf_buffer_sample_fn sample_cb, perf_buffer_lost_fn lost_cb, void *ctx,
1170 		 const struct perf_buffer_opts *opts);
1171 
1172 enum bpf_perf_event_ret {
1173 	LIBBPF_PERF_EVENT_DONE	= 0,
1174 	LIBBPF_PERF_EVENT_ERROR	= -1,
1175 	LIBBPF_PERF_EVENT_CONT	= -2,
1176 };
1177 
1178 struct perf_event_header;
1179 
1180 typedef enum bpf_perf_event_ret
1181 (*perf_buffer_event_fn)(void *ctx, int cpu, struct perf_event_header *event);
1182 
1183 /* raw perf buffer options, giving most power and control */
1184 struct perf_buffer_raw_opts {
1185 	size_t sz;
1186 	long :0;
1187 	long :0;
1188 	/* if cpu_cnt == 0, open all on all possible CPUs (up to the number of
1189 	 * max_entries of given PERF_EVENT_ARRAY map)
1190 	 */
1191 	int cpu_cnt;
1192 	/* if cpu_cnt > 0, cpus is an array of CPUs to open ring buffers on */
1193 	int *cpus;
1194 	/* if cpu_cnt > 0, map_keys specify map keys to set per-CPU FDs for */
1195 	int *map_keys;
1196 };
1197 #define perf_buffer_raw_opts__last_field map_keys
1198 
1199 struct perf_event_attr;
1200 
1201 LIBBPF_API struct perf_buffer *
1202 perf_buffer__new_raw(int map_fd, size_t page_cnt, struct perf_event_attr *attr,
1203 		     perf_buffer_event_fn event_cb, void *ctx,
1204 		     const struct perf_buffer_raw_opts *opts);
1205 
1206 LIBBPF_API void perf_buffer__free(struct perf_buffer *pb);
1207 LIBBPF_API int perf_buffer__epoll_fd(const struct perf_buffer *pb);
1208 LIBBPF_API int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms);
1209 LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb);
1210 LIBBPF_API int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx);
1211 LIBBPF_API size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb);
1212 LIBBPF_API int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx);
1213 /**
1214  * @brief **perf_buffer__buffer()** returns the per-cpu raw mmap()'ed underlying
1215  * memory region of the ring buffer.
1216  * This ring buffer can be used to implement a custom events consumer.
1217  * The ring buffer starts with the *struct perf_event_mmap_page*, which
1218  * holds the ring buffer managment fields, when accessing the header
1219  * structure it's important to be SMP aware.
1220  * You can refer to *perf_event_read_simple* for a simple example.
1221  * @param pb the perf buffer structure
1222  * @param buf_idx the buffer index to retreive
1223  * @param buf (out) gets the base pointer of the mmap()'ed memory
1224  * @param buf_size (out) gets the size of the mmap()'ed region
1225  * @return 0 on success, negative error code for failure
1226  */
1227 LIBBPF_API int perf_buffer__buffer(struct perf_buffer *pb, int buf_idx, void **buf,
1228 				   size_t *buf_size);
1229 
1230 struct bpf_prog_linfo;
1231 struct bpf_prog_info;
1232 
1233 LIBBPF_API void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo);
1234 LIBBPF_API struct bpf_prog_linfo *
1235 bpf_prog_linfo__new(const struct bpf_prog_info *info);
1236 LIBBPF_API const struct bpf_line_info *
1237 bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo,
1238 				__u64 addr, __u32 func_idx, __u32 nr_skip);
1239 LIBBPF_API const struct bpf_line_info *
1240 bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo,
1241 		      __u32 insn_off, __u32 nr_skip);
1242 
1243 /*
1244  * Probe for supported system features
1245  *
1246  * Note that running many of these probes in a short amount of time can cause
1247  * the kernel to reach the maximal size of lockable memory allowed for the
1248  * user, causing subsequent probes to fail. In this case, the caller may want
1249  * to adjust that limit with setrlimit().
1250  */
1251 
1252 /**
1253  * @brief **libbpf_probe_bpf_prog_type()** detects if host kernel supports
1254  * BPF programs of a given type.
1255  * @param prog_type BPF program type to detect kernel support for
1256  * @param opts reserved for future extensibility, should be NULL
1257  * @return 1, if given program type is supported; 0, if given program type is
1258  * not supported; negative error code if feature detection failed or can't be
1259  * performed
1260  *
1261  * Make sure the process has required set of CAP_* permissions (or runs as
1262  * root) when performing feature checking.
1263  */
1264 LIBBPF_API int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts);
1265 /**
1266  * @brief **libbpf_probe_bpf_map_type()** detects if host kernel supports
1267  * BPF maps of a given type.
1268  * @param map_type BPF map type to detect kernel support for
1269  * @param opts reserved for future extensibility, should be NULL
1270  * @return 1, if given map type is supported; 0, if given map type is
1271  * not supported; negative error code if feature detection failed or can't be
1272  * performed
1273  *
1274  * Make sure the process has required set of CAP_* permissions (or runs as
1275  * root) when performing feature checking.
1276  */
1277 LIBBPF_API int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts);
1278 /**
1279  * @brief **libbpf_probe_bpf_helper()** detects if host kernel supports the
1280  * use of a given BPF helper from specified BPF program type.
1281  * @param prog_type BPF program type used to check the support of BPF helper
1282  * @param helper_id BPF helper ID (enum bpf_func_id) to check support for
1283  * @param opts reserved for future extensibility, should be NULL
1284  * @return 1, if given combination of program type and helper is supported; 0,
1285  * if the combination is not supported; negative error code if feature
1286  * detection for provided input arguments failed or can't be performed
1287  *
1288  * Make sure the process has required set of CAP_* permissions (or runs as
1289  * root) when performing feature checking.
1290  */
1291 LIBBPF_API int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type,
1292 				       enum bpf_func_id helper_id, const void *opts);
1293 
1294 /**
1295  * @brief **libbpf_num_possible_cpus()** is a helper function to get the
1296  * number of possible CPUs that the host kernel supports and expects.
1297  * @return number of possible CPUs; or error code on failure
1298  *
1299  * Example usage:
1300  *
1301  *     int ncpus = libbpf_num_possible_cpus();
1302  *     if (ncpus < 0) {
1303  *          // error handling
1304  *     }
1305  *     long values[ncpus];
1306  *     bpf_map_lookup_elem(per_cpu_map_fd, key, values);
1307  */
1308 LIBBPF_API int libbpf_num_possible_cpus(void);
1309 
1310 struct bpf_map_skeleton {
1311 	const char *name;
1312 	struct bpf_map **map;
1313 	void **mmaped;
1314 };
1315 
1316 struct bpf_prog_skeleton {
1317 	const char *name;
1318 	struct bpf_program **prog;
1319 	struct bpf_link **link;
1320 };
1321 
1322 struct bpf_object_skeleton {
1323 	size_t sz; /* size of this struct, for forward/backward compatibility */
1324 
1325 	const char *name;
1326 	const void *data;
1327 	size_t data_sz;
1328 
1329 	struct bpf_object **obj;
1330 
1331 	int map_cnt;
1332 	int map_skel_sz; /* sizeof(struct bpf_map_skeleton) */
1333 	struct bpf_map_skeleton *maps;
1334 
1335 	int prog_cnt;
1336 	int prog_skel_sz; /* sizeof(struct bpf_prog_skeleton) */
1337 	struct bpf_prog_skeleton *progs;
1338 };
1339 
1340 LIBBPF_API int
1341 bpf_object__open_skeleton(struct bpf_object_skeleton *s,
1342 			  const struct bpf_object_open_opts *opts);
1343 LIBBPF_API int bpf_object__load_skeleton(struct bpf_object_skeleton *s);
1344 LIBBPF_API int bpf_object__attach_skeleton(struct bpf_object_skeleton *s);
1345 LIBBPF_API void bpf_object__detach_skeleton(struct bpf_object_skeleton *s);
1346 LIBBPF_API void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s);
1347 
1348 struct bpf_var_skeleton {
1349 	const char *name;
1350 	struct bpf_map **map;
1351 	void **addr;
1352 };
1353 
1354 struct bpf_object_subskeleton {
1355 	size_t sz; /* size of this struct, for forward/backward compatibility */
1356 
1357 	const struct bpf_object *obj;
1358 
1359 	int map_cnt;
1360 	int map_skel_sz; /* sizeof(struct bpf_map_skeleton) */
1361 	struct bpf_map_skeleton *maps;
1362 
1363 	int prog_cnt;
1364 	int prog_skel_sz; /* sizeof(struct bpf_prog_skeleton) */
1365 	struct bpf_prog_skeleton *progs;
1366 
1367 	int var_cnt;
1368 	int var_skel_sz; /* sizeof(struct bpf_var_skeleton) */
1369 	struct bpf_var_skeleton *vars;
1370 };
1371 
1372 LIBBPF_API int
1373 bpf_object__open_subskeleton(struct bpf_object_subskeleton *s);
1374 LIBBPF_API void
1375 bpf_object__destroy_subskeleton(struct bpf_object_subskeleton *s);
1376 
1377 struct gen_loader_opts {
1378 	size_t sz; /* size of this struct, for forward/backward compatiblity */
1379 	const char *data;
1380 	const char *insns;
1381 	__u32 data_sz;
1382 	__u32 insns_sz;
1383 };
1384 
1385 #define gen_loader_opts__last_field insns_sz
1386 LIBBPF_API int bpf_object__gen_loader(struct bpf_object *obj,
1387 				      struct gen_loader_opts *opts);
1388 
1389 enum libbpf_tristate {
1390 	TRI_NO = 0,
1391 	TRI_YES = 1,
1392 	TRI_MODULE = 2,
1393 };
1394 
1395 struct bpf_linker_opts {
1396 	/* size of this struct, for forward/backward compatiblity */
1397 	size_t sz;
1398 };
1399 #define bpf_linker_opts__last_field sz
1400 
1401 struct bpf_linker_file_opts {
1402 	/* size of this struct, for forward/backward compatiblity */
1403 	size_t sz;
1404 };
1405 #define bpf_linker_file_opts__last_field sz
1406 
1407 struct bpf_linker;
1408 
1409 LIBBPF_API struct bpf_linker *bpf_linker__new(const char *filename, struct bpf_linker_opts *opts);
1410 LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker,
1411 				    const char *filename,
1412 				    const struct bpf_linker_file_opts *opts);
1413 LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker);
1414 LIBBPF_API void bpf_linker__free(struct bpf_linker *linker);
1415 
1416 /*
1417  * Custom handling of BPF program's SEC() definitions
1418  */
1419 
1420 struct bpf_prog_load_opts; /* defined in bpf.h */
1421 
1422 /* Called during bpf_object__open() for each recognized BPF program. Callback
1423  * can use various bpf_program__set_*() setters to adjust whatever properties
1424  * are necessary.
1425  */
1426 typedef int (*libbpf_prog_setup_fn_t)(struct bpf_program *prog, long cookie);
1427 
1428 /* Called right before libbpf performs bpf_prog_load() to load BPF program
1429  * into the kernel. Callback can adjust opts as necessary.
1430  */
1431 typedef int (*libbpf_prog_prepare_load_fn_t)(struct bpf_program *prog,
1432 					     struct bpf_prog_load_opts *opts, long cookie);
1433 
1434 /* Called during skeleton attach or through bpf_program__attach(). If
1435  * auto-attach is not supported, callback should return 0 and set link to
1436  * NULL (it's not considered an error during skeleton attach, but it will be
1437  * an error for bpf_program__attach() calls). On error, error should be
1438  * returned directly and link set to NULL. On success, return 0 and set link
1439  * to a valid struct bpf_link.
1440  */
1441 typedef int (*libbpf_prog_attach_fn_t)(const struct bpf_program *prog, long cookie,
1442 				       struct bpf_link **link);
1443 
1444 struct libbpf_prog_handler_opts {
1445 	/* size of this struct, for forward/backward compatiblity */
1446 	size_t sz;
1447 	/* User-provided value that is passed to prog_setup_fn,
1448 	 * prog_prepare_load_fn, and prog_attach_fn callbacks. Allows user to
1449 	 * register one set of callbacks for multiple SEC() definitions and
1450 	 * still be able to distinguish them, if necessary. For example,
1451 	 * libbpf itself is using this to pass necessary flags (e.g.,
1452 	 * sleepable flag) to a common internal SEC() handler.
1453 	 */
1454 	long cookie;
1455 	/* BPF program initialization callback (see libbpf_prog_setup_fn_t).
1456 	 * Callback is optional, pass NULL if it's not necessary.
1457 	 */
1458 	libbpf_prog_setup_fn_t prog_setup_fn;
1459 	/* BPF program loading callback (see libbpf_prog_prepare_load_fn_t).
1460 	 * Callback is optional, pass NULL if it's not necessary.
1461 	 */
1462 	libbpf_prog_prepare_load_fn_t prog_prepare_load_fn;
1463 	/* BPF program attach callback (see libbpf_prog_attach_fn_t).
1464 	 * Callback is optional, pass NULL if it's not necessary.
1465 	 */
1466 	libbpf_prog_attach_fn_t prog_attach_fn;
1467 };
1468 #define libbpf_prog_handler_opts__last_field prog_attach_fn
1469 
1470 /**
1471  * @brief **libbpf_register_prog_handler()** registers a custom BPF program
1472  * SEC() handler.
1473  * @param sec section prefix for which custom handler is registered
1474  * @param prog_type BPF program type associated with specified section
1475  * @param exp_attach_type Expected BPF attach type associated with specified section
1476  * @param opts optional cookie, callbacks, and other extra options
1477  * @return Non-negative handler ID is returned on success. This handler ID has
1478  * to be passed to *libbpf_unregister_prog_handler()* to unregister such
1479  * custom handler. Negative error code is returned on error.
1480  *
1481  * *sec* defines which SEC() definitions are handled by this custom handler
1482  * registration. *sec* can have few different forms:
1483  *   - if *sec* is just a plain string (e.g., "abc"), it will match only
1484  *   SEC("abc"). If BPF program specifies SEC("abc/whatever") it will result
1485  *   in an error;
1486  *   - if *sec* is of the form "abc/", proper SEC() form is
1487  *   SEC("abc/something"), where acceptable "something" should be checked by
1488  *   *prog_init_fn* callback, if there are additional restrictions;
1489  *   - if *sec* is of the form "abc+", it will successfully match both
1490  *   SEC("abc") and SEC("abc/whatever") forms;
1491  *   - if *sec* is NULL, custom handler is registered for any BPF program that
1492  *   doesn't match any of the registered (custom or libbpf's own) SEC()
1493  *   handlers. There could be only one such generic custom handler registered
1494  *   at any given time.
1495  *
1496  * All custom handlers (except the one with *sec* == NULL) are processed
1497  * before libbpf's own SEC() handlers. It is allowed to "override" libbpf's
1498  * SEC() handlers by registering custom ones for the same section prefix
1499  * (i.e., it's possible to have custom SEC("perf_event/LLC-load-misses")
1500  * handler).
1501  *
1502  * Note, like much of global libbpf APIs (e.g., libbpf_set_print(),
1503  * libbpf_set_strict_mode(), etc)) these APIs are not thread-safe. User needs
1504  * to ensure synchronization if there is a risk of running this API from
1505  * multiple threads simultaneously.
1506  */
1507 LIBBPF_API int libbpf_register_prog_handler(const char *sec,
1508 					    enum bpf_prog_type prog_type,
1509 					    enum bpf_attach_type exp_attach_type,
1510 					    const struct libbpf_prog_handler_opts *opts);
1511 /**
1512  * @brief *libbpf_unregister_prog_handler()* unregisters previously registered
1513  * custom BPF program SEC() handler.
1514  * @param handler_id handler ID returned by *libbpf_register_prog_handler()*
1515  * after successful registration
1516  * @return 0 on success, negative error code if handler isn't found
1517  *
1518  * Note, like much of global libbpf APIs (e.g., libbpf_set_print(),
1519  * libbpf_set_strict_mode(), etc)) these APIs are not thread-safe. User needs
1520  * to ensure synchronization if there is a risk of running this API from
1521  * multiple threads simultaneously.
1522  */
1523 LIBBPF_API int libbpf_unregister_prog_handler(int handler_id);
1524 
1525 #ifdef __cplusplus
1526 } /* extern "C" */
1527 #endif
1528 
1529 #endif /* __LIBBPF_LIBBPF_H */
1530