• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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  * Copyright (C) 2017 Nicira, Inc.
10  * Copyright (C) 2019 Isovalent, Inc.
11  */
12 
13 #ifndef _GNU_SOURCE
14 #define _GNU_SOURCE
15 #endif
16 #include <stdlib.h>
17 #include <stdio.h>
18 #include <stdarg.h>
19 #include <libgen.h>
20 #include <inttypes.h>
21 #include <string.h>
22 #include <unistd.h>
23 #include <endian.h>
24 #include <fcntl.h>
25 #include <errno.h>
26 #include <asm/unistd.h>
27 #include <linux/err.h>
28 #include <linux/kernel.h>
29 #include <linux/bpf.h>
30 #include <linux/btf.h>
31 #include <linux/filter.h>
32 #include <linux/list.h>
33 #include <linux/limits.h>
34 #include <linux/perf_event.h>
35 #include <linux/ring_buffer.h>
36 #include <sys/epoll.h>
37 #include <sys/ioctl.h>
38 #include <sys/mman.h>
39 #include <sys/stat.h>
40 #include <sys/types.h>
41 #include <sys/vfs.h>
42 #include <sys/utsname.h>
43 #include <tools/libc_compat.h>
44 #include <libelf.h>
45 #include <gelf.h>
46 
47 #include "libbpf.h"
48 #include "bpf.h"
49 #include "btf.h"
50 #include "str_error.h"
51 #include "libbpf_internal.h"
52 #include "hashmap.h"
53 
54 #ifndef EM_BPF
55 #define EM_BPF 247
56 #endif
57 
58 #ifndef BPF_FS_MAGIC
59 #define BPF_FS_MAGIC		0xcafe4a11
60 #endif
61 
62 /* vsprintf() in __base_pr() uses nonliteral format string. It may break
63  * compilation if user enables corresponding warning. Disable it explicitly.
64  */
65 #pragma GCC diagnostic ignored "-Wformat-nonliteral"
66 
67 #define __printf(a, b)	__attribute__((format(printf, a, b)))
68 
__base_pr(enum libbpf_print_level level,const char * format,va_list args)69 static int __base_pr(enum libbpf_print_level level, const char *format,
70 		     va_list args)
71 {
72 	if (level == LIBBPF_DEBUG)
73 		return 0;
74 
75 	return vfprintf(stderr, format, args);
76 }
77 
78 static libbpf_print_fn_t __libbpf_pr = __base_pr;
79 
libbpf_set_print(libbpf_print_fn_t fn)80 libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
81 {
82 	libbpf_print_fn_t old_print_fn = __libbpf_pr;
83 
84 	__libbpf_pr = fn;
85 	return old_print_fn;
86 }
87 
88 __printf(2, 3)
libbpf_print(enum libbpf_print_level level,const char * format,...)89 void libbpf_print(enum libbpf_print_level level, const char *format, ...)
90 {
91 	va_list args;
92 
93 	if (!__libbpf_pr)
94 		return;
95 
96 	va_start(args, format);
97 	__libbpf_pr(level, format, args);
98 	va_end(args);
99 }
100 
101 #define STRERR_BUFSIZE  128
102 
103 #define CHECK_ERR(action, err, out) do {	\
104 	err = action;			\
105 	if (err)			\
106 		goto out;		\
107 } while(0)
108 
109 
110 /* Copied from tools/perf/util/util.h */
111 #ifndef zfree
112 # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
113 #endif
114 
115 #ifndef zclose
116 # define zclose(fd) ({			\
117 	int ___err = 0;			\
118 	if ((fd) >= 0)			\
119 		___err = close((fd));	\
120 	fd = -1;			\
121 	___err; })
122 #endif
123 
124 #ifdef HAVE_LIBELF_MMAP_SUPPORT
125 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
126 #else
127 # define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
128 #endif
129 
ptr_to_u64(const void * ptr)130 static inline __u64 ptr_to_u64(const void *ptr)
131 {
132 	return (__u64) (unsigned long) ptr;
133 }
134 
135 struct bpf_capabilities {
136 	/* v4.14: kernel support for program & map names. */
137 	__u32 name:1;
138 	/* v5.2: kernel support for global data sections. */
139 	__u32 global_data:1;
140 	/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
141 	__u32 btf_func:1;
142 	/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
143 	__u32 btf_datasec:1;
144 };
145 
146 /*
147  * bpf_prog should be a better name but it has been used in
148  * linux/filter.h.
149  */
150 struct bpf_program {
151 	/* Index in elf obj file, for relocation use. */
152 	int idx;
153 	char *name;
154 	int prog_ifindex;
155 	char *section_name;
156 	/* section_name with / replaced by _; makes recursive pinning
157 	 * in bpf_object__pin_programs easier
158 	 */
159 	char *pin_name;
160 	struct bpf_insn *insns;
161 	size_t insns_cnt, main_prog_cnt;
162 	enum bpf_prog_type type;
163 
164 	struct reloc_desc {
165 		enum {
166 			RELO_LD64,
167 			RELO_CALL,
168 			RELO_DATA,
169 		} type;
170 		int insn_idx;
171 		union {
172 			int map_idx;
173 			int text_off;
174 		};
175 	} *reloc_desc;
176 	int nr_reloc;
177 	int log_level;
178 
179 	struct {
180 		int nr;
181 		int *fds;
182 	} instances;
183 	bpf_program_prep_t preprocessor;
184 
185 	struct bpf_object *obj;
186 	void *priv;
187 	bpf_program_clear_priv_t clear_priv;
188 
189 	enum bpf_attach_type expected_attach_type;
190 	void *func_info;
191 	__u32 func_info_rec_size;
192 	__u32 func_info_cnt;
193 
194 	struct bpf_capabilities *caps;
195 
196 	void *line_info;
197 	__u32 line_info_rec_size;
198 	__u32 line_info_cnt;
199 	__u32 prog_flags;
200 };
201 
202 enum libbpf_map_type {
203 	LIBBPF_MAP_UNSPEC,
204 	LIBBPF_MAP_DATA,
205 	LIBBPF_MAP_BSS,
206 	LIBBPF_MAP_RODATA,
207 };
208 
209 static const char * const libbpf_type_to_btf_name[] = {
210 	[LIBBPF_MAP_DATA]	= ".data",
211 	[LIBBPF_MAP_BSS]	= ".bss",
212 	[LIBBPF_MAP_RODATA]	= ".rodata",
213 };
214 
215 struct bpf_map {
216 	int fd;
217 	char *name;
218 	int sec_idx;
219 	size_t sec_offset;
220 	int map_ifindex;
221 	int inner_map_fd;
222 	struct bpf_map_def def;
223 	__u32 btf_key_type_id;
224 	__u32 btf_value_type_id;
225 	void *priv;
226 	bpf_map_clear_priv_t clear_priv;
227 	enum libbpf_map_type libbpf_type;
228 };
229 
230 struct bpf_secdata {
231 	void *rodata;
232 	void *data;
233 };
234 
235 static LIST_HEAD(bpf_objects_list);
236 
237 struct bpf_object {
238 	char name[BPF_OBJ_NAME_LEN];
239 	char license[64];
240 	__u32 kern_version;
241 
242 	struct bpf_program *programs;
243 	size_t nr_programs;
244 	struct bpf_map *maps;
245 	size_t nr_maps;
246 	size_t maps_cap;
247 	struct bpf_secdata sections;
248 
249 	bool loaded;
250 	bool has_pseudo_calls;
251 
252 	/*
253 	 * Information when doing elf related work. Only valid if fd
254 	 * is valid.
255 	 */
256 	struct {
257 		int fd;
258 		void *obj_buf;
259 		size_t obj_buf_sz;
260 		Elf *elf;
261 		GElf_Ehdr ehdr;
262 		Elf_Data *symbols;
263 		Elf_Data *data;
264 		Elf_Data *rodata;
265 		Elf_Data *bss;
266 		size_t strtabidx;
267 		struct {
268 			GElf_Shdr shdr;
269 			Elf_Data *data;
270 		} *reloc;
271 		int nr_reloc;
272 		int maps_shndx;
273 		int btf_maps_shndx;
274 		int text_shndx;
275 		int data_shndx;
276 		int rodata_shndx;
277 		int bss_shndx;
278 	} efile;
279 	/*
280 	 * All loaded bpf_object is linked in a list, which is
281 	 * hidden to caller. bpf_objects__<func> handlers deal with
282 	 * all objects.
283 	 */
284 	struct list_head list;
285 
286 	struct btf *btf;
287 	struct btf_ext *btf_ext;
288 
289 	void *priv;
290 	bpf_object_clear_priv_t clear_priv;
291 
292 	struct bpf_capabilities caps;
293 
294 	char path[];
295 };
296 #define obj_elf_valid(o)	((o)->efile.elf)
297 
bpf_program__unload(struct bpf_program * prog)298 void bpf_program__unload(struct bpf_program *prog)
299 {
300 	int i;
301 
302 	if (!prog)
303 		return;
304 
305 	/*
306 	 * If the object is opened but the program was never loaded,
307 	 * it is possible that prog->instances.nr == -1.
308 	 */
309 	if (prog->instances.nr > 0) {
310 		for (i = 0; i < prog->instances.nr; i++)
311 			zclose(prog->instances.fds[i]);
312 	} else if (prog->instances.nr != -1) {
313 		pr_warning("Internal error: instances.nr is %d\n",
314 			   prog->instances.nr);
315 	}
316 
317 	prog->instances.nr = -1;
318 	zfree(&prog->instances.fds);
319 
320 	zfree(&prog->func_info);
321 	zfree(&prog->line_info);
322 }
323 
bpf_program__exit(struct bpf_program * prog)324 static void bpf_program__exit(struct bpf_program *prog)
325 {
326 	if (!prog)
327 		return;
328 
329 	if (prog->clear_priv)
330 		prog->clear_priv(prog, prog->priv);
331 
332 	prog->priv = NULL;
333 	prog->clear_priv = NULL;
334 
335 	bpf_program__unload(prog);
336 	zfree(&prog->name);
337 	zfree(&prog->section_name);
338 	zfree(&prog->pin_name);
339 	zfree(&prog->insns);
340 	zfree(&prog->reloc_desc);
341 
342 	prog->nr_reloc = 0;
343 	prog->insns_cnt = 0;
344 	prog->idx = -1;
345 }
346 
__bpf_program__pin_name(struct bpf_program * prog)347 static char *__bpf_program__pin_name(struct bpf_program *prog)
348 {
349 	char *name, *p;
350 
351 	name = p = strdup(prog->section_name);
352 	while ((p = strchr(p, '/')))
353 		*p = '_';
354 
355 	return name;
356 }
357 
358 static int
bpf_program__init(void * data,size_t size,char * section_name,int idx,struct bpf_program * prog)359 bpf_program__init(void *data, size_t size, char *section_name, int idx,
360 		  struct bpf_program *prog)
361 {
362 	const size_t bpf_insn_sz = sizeof(struct bpf_insn);
363 
364 	if (size == 0 || size % bpf_insn_sz) {
365 		pr_warning("corrupted section '%s', size: %zu\n",
366 			   section_name, size);
367 		return -EINVAL;
368 	}
369 
370 	memset(prog, 0, sizeof(*prog));
371 
372 	prog->section_name = strdup(section_name);
373 	if (!prog->section_name) {
374 		pr_warning("failed to alloc name for prog under section(%d) %s\n",
375 			   idx, section_name);
376 		goto errout;
377 	}
378 
379 	prog->pin_name = __bpf_program__pin_name(prog);
380 	if (!prog->pin_name) {
381 		pr_warning("failed to alloc pin name for prog under section(%d) %s\n",
382 			   idx, section_name);
383 		goto errout;
384 	}
385 
386 	prog->insns = malloc(size);
387 	if (!prog->insns) {
388 		pr_warning("failed to alloc insns for prog under section %s\n",
389 			   section_name);
390 		goto errout;
391 	}
392 	prog->insns_cnt = size / bpf_insn_sz;
393 	memcpy(prog->insns, data, size);
394 	prog->idx = idx;
395 	prog->instances.fds = NULL;
396 	prog->instances.nr = -1;
397 	prog->type = BPF_PROG_TYPE_UNSPEC;
398 
399 	return 0;
400 errout:
401 	bpf_program__exit(prog);
402 	return -ENOMEM;
403 }
404 
405 static int
bpf_object__add_program(struct bpf_object * obj,void * data,size_t size,char * section_name,int idx)406 bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
407 			char *section_name, int idx)
408 {
409 	struct bpf_program prog, *progs;
410 	int nr_progs, err;
411 
412 	err = bpf_program__init(data, size, section_name, idx, &prog);
413 	if (err)
414 		return err;
415 
416 	prog.caps = &obj->caps;
417 	progs = obj->programs;
418 	nr_progs = obj->nr_programs;
419 
420 	progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
421 	if (!progs) {
422 		/*
423 		 * In this case the original obj->programs
424 		 * is still valid, so don't need special treat for
425 		 * bpf_close_object().
426 		 */
427 		pr_warning("failed to alloc a new program under section '%s'\n",
428 			   section_name);
429 		bpf_program__exit(&prog);
430 		return -ENOMEM;
431 	}
432 
433 	pr_debug("found program %s\n", prog.section_name);
434 	obj->programs = progs;
435 	obj->nr_programs = nr_progs + 1;
436 	prog.obj = obj;
437 	progs[nr_progs] = prog;
438 	return 0;
439 }
440 
441 static int
bpf_object__init_prog_names(struct bpf_object * obj)442 bpf_object__init_prog_names(struct bpf_object *obj)
443 {
444 	Elf_Data *symbols = obj->efile.symbols;
445 	struct bpf_program *prog;
446 	size_t pi, si;
447 
448 	for (pi = 0; pi < obj->nr_programs; pi++) {
449 		const char *name = NULL;
450 
451 		prog = &obj->programs[pi];
452 
453 		for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
454 		     si++) {
455 			GElf_Sym sym;
456 
457 			if (!gelf_getsym(symbols, si, &sym))
458 				continue;
459 			if (sym.st_shndx != prog->idx)
460 				continue;
461 			if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
462 				continue;
463 
464 			name = elf_strptr(obj->efile.elf,
465 					  obj->efile.strtabidx,
466 					  sym.st_name);
467 			if (!name) {
468 				pr_warning("failed to get sym name string for prog %s\n",
469 					   prog->section_name);
470 				return -LIBBPF_ERRNO__LIBELF;
471 			}
472 		}
473 
474 		if (!name && prog->idx == obj->efile.text_shndx)
475 			name = ".text";
476 
477 		if (!name) {
478 			pr_warning("failed to find sym for prog %s\n",
479 				   prog->section_name);
480 			return -EINVAL;
481 		}
482 
483 		prog->name = strdup(name);
484 		if (!prog->name) {
485 			pr_warning("failed to allocate memory for prog sym %s\n",
486 				   name);
487 			return -ENOMEM;
488 		}
489 	}
490 
491 	return 0;
492 }
493 
bpf_object__new(const char * path,void * obj_buf,size_t obj_buf_sz)494 static struct bpf_object *bpf_object__new(const char *path,
495 					  void *obj_buf,
496 					  size_t obj_buf_sz)
497 {
498 	struct bpf_object *obj;
499 	char *end;
500 
501 	obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
502 	if (!obj) {
503 		pr_warning("alloc memory failed for %s\n", path);
504 		return ERR_PTR(-ENOMEM);
505 	}
506 
507 	strcpy(obj->path, path);
508 	/* Using basename() GNU version which doesn't modify arg. */
509 	strncpy(obj->name, basename((void *)path), sizeof(obj->name) - 1);
510 	end = strchr(obj->name, '.');
511 	if (end)
512 		*end = 0;
513 
514 	obj->efile.fd = -1;
515 	/*
516 	 * Caller of this function should also call
517 	 * bpf_object__elf_finish() after data collection to return
518 	 * obj_buf to user. If not, we should duplicate the buffer to
519 	 * avoid user freeing them before elf finish.
520 	 */
521 	obj->efile.obj_buf = obj_buf;
522 	obj->efile.obj_buf_sz = obj_buf_sz;
523 	obj->efile.maps_shndx = -1;
524 	obj->efile.btf_maps_shndx = -1;
525 	obj->efile.data_shndx = -1;
526 	obj->efile.rodata_shndx = -1;
527 	obj->efile.bss_shndx = -1;
528 
529 	obj->loaded = false;
530 
531 	INIT_LIST_HEAD(&obj->list);
532 	list_add(&obj->list, &bpf_objects_list);
533 	return obj;
534 }
535 
bpf_object__elf_finish(struct bpf_object * obj)536 static void bpf_object__elf_finish(struct bpf_object *obj)
537 {
538 	if (!obj_elf_valid(obj))
539 		return;
540 
541 	if (obj->efile.elf) {
542 		elf_end(obj->efile.elf);
543 		obj->efile.elf = NULL;
544 	}
545 	obj->efile.symbols = NULL;
546 	obj->efile.data = NULL;
547 	obj->efile.rodata = NULL;
548 	obj->efile.bss = NULL;
549 
550 	zfree(&obj->efile.reloc);
551 	obj->efile.nr_reloc = 0;
552 	zclose(obj->efile.fd);
553 	obj->efile.obj_buf = NULL;
554 	obj->efile.obj_buf_sz = 0;
555 }
556 
bpf_object__elf_init(struct bpf_object * obj)557 static int bpf_object__elf_init(struct bpf_object *obj)
558 {
559 	int err = 0;
560 	GElf_Ehdr *ep;
561 
562 	if (obj_elf_valid(obj)) {
563 		pr_warning("elf init: internal error\n");
564 		return -LIBBPF_ERRNO__LIBELF;
565 	}
566 
567 	if (obj->efile.obj_buf_sz > 0) {
568 		/*
569 		 * obj_buf should have been validated by
570 		 * bpf_object__open_buffer().
571 		 */
572 		obj->efile.elf = elf_memory(obj->efile.obj_buf,
573 					    obj->efile.obj_buf_sz);
574 	} else {
575 		obj->efile.fd = open(obj->path, O_RDONLY);
576 		if (obj->efile.fd < 0) {
577 			char errmsg[STRERR_BUFSIZE], *cp;
578 
579 			err = -errno;
580 			cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
581 			pr_warning("failed to open %s: %s\n", obj->path, cp);
582 			return err;
583 		}
584 
585 		obj->efile.elf = elf_begin(obj->efile.fd,
586 					   LIBBPF_ELF_C_READ_MMAP, NULL);
587 	}
588 
589 	if (!obj->efile.elf) {
590 		pr_warning("failed to open %s as ELF file\n", obj->path);
591 		err = -LIBBPF_ERRNO__LIBELF;
592 		goto errout;
593 	}
594 
595 	if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
596 		pr_warning("failed to get EHDR from %s\n", obj->path);
597 		err = -LIBBPF_ERRNO__FORMAT;
598 		goto errout;
599 	}
600 	ep = &obj->efile.ehdr;
601 
602 	/* Old LLVM set e_machine to EM_NONE */
603 	if (ep->e_type != ET_REL ||
604 	    (ep->e_machine && ep->e_machine != EM_BPF)) {
605 		pr_warning("%s is not an eBPF object file\n", obj->path);
606 		err = -LIBBPF_ERRNO__FORMAT;
607 		goto errout;
608 	}
609 
610 	return 0;
611 errout:
612 	bpf_object__elf_finish(obj);
613 	return err;
614 }
615 
bpf_object__check_endianness(struct bpf_object * obj)616 static int bpf_object__check_endianness(struct bpf_object *obj)
617 {
618 #if __BYTE_ORDER == __LITTLE_ENDIAN
619 	if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
620 		return 0;
621 #elif __BYTE_ORDER == __BIG_ENDIAN
622 	if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
623 		return 0;
624 #else
625 # error "Unrecognized __BYTE_ORDER__"
626 #endif
627 	pr_warning("endianness mismatch.\n");
628 	return -LIBBPF_ERRNO__ENDIAN;
629 }
630 
631 static int
bpf_object__init_license(struct bpf_object * obj,void * data,size_t size)632 bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
633 {
634 	memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
635 	pr_debug("license of %s is %s\n", obj->path, obj->license);
636 	return 0;
637 }
638 
639 static int
bpf_object__init_kversion(struct bpf_object * obj,void * data,size_t size)640 bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
641 {
642 	__u32 kver;
643 
644 	if (size != sizeof(kver)) {
645 		pr_warning("invalid kver section in %s\n", obj->path);
646 		return -LIBBPF_ERRNO__FORMAT;
647 	}
648 	memcpy(&kver, data, sizeof(kver));
649 	obj->kern_version = kver;
650 	pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
651 	return 0;
652 }
653 
compare_bpf_map(const void * _a,const void * _b)654 static int compare_bpf_map(const void *_a, const void *_b)
655 {
656 	const struct bpf_map *a = _a;
657 	const struct bpf_map *b = _b;
658 
659 	if (a->sec_idx != b->sec_idx)
660 		return a->sec_idx - b->sec_idx;
661 	return a->sec_offset - b->sec_offset;
662 }
663 
bpf_map_type__is_map_in_map(enum bpf_map_type type)664 static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
665 {
666 	if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
667 	    type == BPF_MAP_TYPE_HASH_OF_MAPS)
668 		return true;
669 	return false;
670 }
671 
bpf_object_search_section_size(const struct bpf_object * obj,const char * name,size_t * d_size)672 static int bpf_object_search_section_size(const struct bpf_object *obj,
673 					  const char *name, size_t *d_size)
674 {
675 	const GElf_Ehdr *ep = &obj->efile.ehdr;
676 	Elf *elf = obj->efile.elf;
677 	Elf_Scn *scn = NULL;
678 	int idx = 0;
679 
680 	while ((scn = elf_nextscn(elf, scn)) != NULL) {
681 		const char *sec_name;
682 		Elf_Data *data;
683 		GElf_Shdr sh;
684 
685 		idx++;
686 		if (gelf_getshdr(scn, &sh) != &sh) {
687 			pr_warning("failed to get section(%d) header from %s\n",
688 				   idx, obj->path);
689 			return -EIO;
690 		}
691 
692 		sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
693 		if (!sec_name) {
694 			pr_warning("failed to get section(%d) name from %s\n",
695 				   idx, obj->path);
696 			return -EIO;
697 		}
698 
699 		if (strcmp(name, sec_name))
700 			continue;
701 
702 		data = elf_getdata(scn, 0);
703 		if (!data) {
704 			pr_warning("failed to get section(%d) data from %s(%s)\n",
705 				   idx, name, obj->path);
706 			return -EIO;
707 		}
708 
709 		*d_size = data->d_size;
710 		return 0;
711 	}
712 
713 	return -ENOENT;
714 }
715 
bpf_object__section_size(const struct bpf_object * obj,const char * name,__u32 * size)716 int bpf_object__section_size(const struct bpf_object *obj, const char *name,
717 			     __u32 *size)
718 {
719 	int ret = -ENOENT;
720 	size_t d_size;
721 
722 	*size = 0;
723 	if (!name) {
724 		return -EINVAL;
725 	} else if (!strcmp(name, ".data")) {
726 		if (obj->efile.data)
727 			*size = obj->efile.data->d_size;
728 	} else if (!strcmp(name, ".bss")) {
729 		if (obj->efile.bss)
730 			*size = obj->efile.bss->d_size;
731 	} else if (!strcmp(name, ".rodata")) {
732 		if (obj->efile.rodata)
733 			*size = obj->efile.rodata->d_size;
734 	} else {
735 		ret = bpf_object_search_section_size(obj, name, &d_size);
736 		if (!ret)
737 			*size = d_size;
738 	}
739 
740 	return *size ? 0 : ret;
741 }
742 
bpf_object__variable_offset(const struct bpf_object * obj,const char * name,__u32 * off)743 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
744 				__u32 *off)
745 {
746 	Elf_Data *symbols = obj->efile.symbols;
747 	const char *sname;
748 	size_t si;
749 
750 	if (!name || !off)
751 		return -EINVAL;
752 
753 	for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
754 		GElf_Sym sym;
755 
756 		if (!gelf_getsym(symbols, si, &sym))
757 			continue;
758 		if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
759 		    GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
760 			continue;
761 
762 		sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
763 				   sym.st_name);
764 		if (!sname) {
765 			pr_warning("failed to get sym name string for var %s\n",
766 				   name);
767 			return -EIO;
768 		}
769 		if (strcmp(name, sname) == 0) {
770 			*off = sym.st_value;
771 			return 0;
772 		}
773 	}
774 
775 	return -ENOENT;
776 }
777 
bpf_object__add_map(struct bpf_object * obj)778 static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
779 {
780 	struct bpf_map *new_maps;
781 	size_t new_cap;
782 	int i;
783 
784 	if (obj->nr_maps < obj->maps_cap)
785 		return &obj->maps[obj->nr_maps++];
786 
787 	new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
788 	new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
789 	if (!new_maps) {
790 		pr_warning("alloc maps for object failed\n");
791 		return ERR_PTR(-ENOMEM);
792 	}
793 
794 	obj->maps_cap = new_cap;
795 	obj->maps = new_maps;
796 
797 	/* zero out new maps */
798 	memset(obj->maps + obj->nr_maps, 0,
799 	       (obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
800 	/*
801 	 * fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
802 	 * when failure (zclose won't close negative fd)).
803 	 */
804 	for (i = obj->nr_maps; i < obj->maps_cap; i++) {
805 		obj->maps[i].fd = -1;
806 		obj->maps[i].inner_map_fd = -1;
807 	}
808 
809 	return &obj->maps[obj->nr_maps++];
810 }
811 
812 static int
bpf_object__init_internal_map(struct bpf_object * obj,enum libbpf_map_type type,int sec_idx,Elf_Data * data,void ** data_buff)813 bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
814 			      int sec_idx, Elf_Data *data, void **data_buff)
815 {
816 	char map_name[BPF_OBJ_NAME_LEN];
817 	struct bpf_map_def *def;
818 	struct bpf_map *map;
819 
820 	map = bpf_object__add_map(obj);
821 	if (IS_ERR(map))
822 		return PTR_ERR(map);
823 
824 	map->libbpf_type = type;
825 	map->sec_idx = sec_idx;
826 	map->sec_offset = 0;
827 	snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
828 		 libbpf_type_to_btf_name[type]);
829 	map->name = strdup(map_name);
830 	if (!map->name) {
831 		pr_warning("failed to alloc map name\n");
832 		return -ENOMEM;
833 	}
834 	pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n",
835 		 map_name, map->sec_idx, map->sec_offset);
836 
837 	def = &map->def;
838 	def->type = BPF_MAP_TYPE_ARRAY;
839 	def->key_size = sizeof(int);
840 	def->value_size = data->d_size;
841 	def->max_entries = 1;
842 	def->map_flags = type == LIBBPF_MAP_RODATA ? BPF_F_RDONLY_PROG : 0;
843 	if (data_buff) {
844 		*data_buff = malloc(data->d_size);
845 		if (!*data_buff) {
846 			zfree(&map->name);
847 			pr_warning("failed to alloc map content buffer\n");
848 			return -ENOMEM;
849 		}
850 		memcpy(*data_buff, data->d_buf, data->d_size);
851 	}
852 
853 	pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
854 	return 0;
855 }
856 
bpf_object__init_global_data_maps(struct bpf_object * obj)857 static int bpf_object__init_global_data_maps(struct bpf_object *obj)
858 {
859 	int err;
860 
861 	if (!obj->caps.global_data)
862 		return 0;
863 	/*
864 	 * Populate obj->maps with libbpf internal maps.
865 	 */
866 	if (obj->efile.data_shndx >= 0) {
867 		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
868 						    obj->efile.data_shndx,
869 						    obj->efile.data,
870 						    &obj->sections.data);
871 		if (err)
872 			return err;
873 	}
874 	if (obj->efile.rodata_shndx >= 0) {
875 		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
876 						    obj->efile.rodata_shndx,
877 						    obj->efile.rodata,
878 						    &obj->sections.rodata);
879 		if (err)
880 			return err;
881 	}
882 	if (obj->efile.bss_shndx >= 0) {
883 		err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
884 						    obj->efile.bss_shndx,
885 						    obj->efile.bss, NULL);
886 		if (err)
887 			return err;
888 	}
889 	return 0;
890 }
891 
bpf_object__init_user_maps(struct bpf_object * obj,bool strict)892 static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
893 {
894 	Elf_Data *symbols = obj->efile.symbols;
895 	int i, map_def_sz = 0, nr_maps = 0, nr_syms;
896 	Elf_Data *data = NULL;
897 	Elf_Scn *scn;
898 
899 	if (obj->efile.maps_shndx < 0)
900 		return 0;
901 
902 	if (!symbols)
903 		return -EINVAL;
904 
905 	scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
906 	if (scn)
907 		data = elf_getdata(scn, NULL);
908 	if (!scn || !data) {
909 		pr_warning("failed to get Elf_Data from map section %d\n",
910 			   obj->efile.maps_shndx);
911 		return -EINVAL;
912 	}
913 
914 	/*
915 	 * Count number of maps. Each map has a name.
916 	 * Array of maps is not supported: only the first element is
917 	 * considered.
918 	 *
919 	 * TODO: Detect array of map and report error.
920 	 */
921 	nr_syms = symbols->d_size / sizeof(GElf_Sym);
922 	for (i = 0; i < nr_syms; i++) {
923 		GElf_Sym sym;
924 
925 		if (!gelf_getsym(symbols, i, &sym))
926 			continue;
927 		if (sym.st_shndx != obj->efile.maps_shndx)
928 			continue;
929 		nr_maps++;
930 	}
931 	/* Assume equally sized map definitions */
932 	pr_debug("maps in %s: %d maps in %zd bytes\n",
933 		 obj->path, nr_maps, data->d_size);
934 
935 	map_def_sz = data->d_size / nr_maps;
936 	if (!data->d_size || (data->d_size % nr_maps) != 0) {
937 		pr_warning("unable to determine map definition size "
938 			   "section %s, %d maps in %zd bytes\n",
939 			   obj->path, nr_maps, data->d_size);
940 		return -EINVAL;
941 	}
942 
943 	/* Fill obj->maps using data in "maps" section.  */
944 	for (i = 0; i < nr_syms; i++) {
945 		GElf_Sym sym;
946 		const char *map_name;
947 		struct bpf_map_def *def;
948 		struct bpf_map *map;
949 
950 		if (!gelf_getsym(symbols, i, &sym))
951 			continue;
952 		if (sym.st_shndx != obj->efile.maps_shndx)
953 			continue;
954 
955 		map = bpf_object__add_map(obj);
956 		if (IS_ERR(map))
957 			return PTR_ERR(map);
958 
959 		map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
960 				      sym.st_name);
961 		if (!map_name) {
962 			pr_warning("failed to get map #%d name sym string for obj %s\n",
963 				   i, obj->path);
964 			return -LIBBPF_ERRNO__FORMAT;
965 		}
966 
967 		map->libbpf_type = LIBBPF_MAP_UNSPEC;
968 		map->sec_idx = sym.st_shndx;
969 		map->sec_offset = sym.st_value;
970 		pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
971 			 map_name, map->sec_idx, map->sec_offset);
972 		if (sym.st_value + map_def_sz > data->d_size) {
973 			pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
974 				   obj->path, map_name);
975 			return -EINVAL;
976 		}
977 
978 		map->name = strdup(map_name);
979 		if (!map->name) {
980 			pr_warning("failed to alloc map name\n");
981 			return -ENOMEM;
982 		}
983 		pr_debug("map %d is \"%s\"\n", i, map->name);
984 		def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
985 		/*
986 		 * If the definition of the map in the object file fits in
987 		 * bpf_map_def, copy it.  Any extra fields in our version
988 		 * of bpf_map_def will default to zero as a result of the
989 		 * calloc above.
990 		 */
991 		if (map_def_sz <= sizeof(struct bpf_map_def)) {
992 			memcpy(&map->def, def, map_def_sz);
993 		} else {
994 			/*
995 			 * Here the map structure being read is bigger than what
996 			 * we expect, truncate if the excess bits are all zero.
997 			 * If they are not zero, reject this map as
998 			 * incompatible.
999 			 */
1000 			char *b;
1001 			for (b = ((char *)def) + sizeof(struct bpf_map_def);
1002 			     b < ((char *)def) + map_def_sz; b++) {
1003 				if (*b != 0) {
1004 					pr_warning("maps section in %s: \"%s\" "
1005 						   "has unrecognized, non-zero "
1006 						   "options\n",
1007 						   obj->path, map_name);
1008 					if (strict)
1009 						return -EINVAL;
1010 				}
1011 			}
1012 			memcpy(&map->def, def, sizeof(struct bpf_map_def));
1013 		}
1014 	}
1015 	return 0;
1016 }
1017 
1018 static const struct btf_type *
skip_mods_and_typedefs(const struct btf * btf,__u32 id,__u32 * res_id)1019 skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
1020 {
1021 	const struct btf_type *t = btf__type_by_id(btf, id);
1022 
1023 	if (res_id)
1024 		*res_id = id;
1025 
1026 	while (btf_is_mod(t) || btf_is_typedef(t)) {
1027 		if (res_id)
1028 			*res_id = t->type;
1029 		t = btf__type_by_id(btf, t->type);
1030 	}
1031 
1032 	return t;
1033 }
1034 
1035 /*
1036  * Fetch integer attribute of BTF map definition. Such attributes are
1037  * represented using a pointer to an array, in which dimensionality of array
1038  * encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
1039  * encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
1040  * type definition, while using only sizeof(void *) space in ELF data section.
1041  */
get_map_field_int(const char * map_name,const struct btf * btf,const struct btf_type * def,const struct btf_member * m,__u32 * res)1042 static bool get_map_field_int(const char *map_name, const struct btf *btf,
1043 			      const struct btf_type *def,
1044 			      const struct btf_member *m, __u32 *res) {
1045 	const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
1046 	const char *name = btf__name_by_offset(btf, m->name_off);
1047 	const struct btf_array *arr_info;
1048 	const struct btf_type *arr_t;
1049 
1050 	if (!btf_is_ptr(t)) {
1051 		pr_warning("map '%s': attr '%s': expected PTR, got %u.\n",
1052 			   map_name, name, btf_kind(t));
1053 		return false;
1054 	}
1055 
1056 	arr_t = btf__type_by_id(btf, t->type);
1057 	if (!arr_t) {
1058 		pr_warning("map '%s': attr '%s': type [%u] not found.\n",
1059 			   map_name, name, t->type);
1060 		return false;
1061 	}
1062 	if (!btf_is_array(arr_t)) {
1063 		pr_warning("map '%s': attr '%s': expected ARRAY, got %u.\n",
1064 			   map_name, name, btf_kind(arr_t));
1065 		return false;
1066 	}
1067 	arr_info = btf_array(arr_t);
1068 	*res = arr_info->nelems;
1069 	return true;
1070 }
1071 
bpf_object__init_user_btf_map(struct bpf_object * obj,const struct btf_type * sec,int var_idx,int sec_idx,const Elf_Data * data,bool strict)1072 static int bpf_object__init_user_btf_map(struct bpf_object *obj,
1073 					 const struct btf_type *sec,
1074 					 int var_idx, int sec_idx,
1075 					 const Elf_Data *data, bool strict)
1076 {
1077 	const struct btf_type *var, *def, *t;
1078 	const struct btf_var_secinfo *vi;
1079 	const struct btf_var *var_extra;
1080 	const struct btf_member *m;
1081 	const char *map_name;
1082 	struct bpf_map *map;
1083 	int vlen, i;
1084 
1085 	vi = btf_var_secinfos(sec) + var_idx;
1086 	var = btf__type_by_id(obj->btf, vi->type);
1087 	var_extra = btf_var(var);
1088 	map_name = btf__name_by_offset(obj->btf, var->name_off);
1089 	vlen = btf_vlen(var);
1090 
1091 	if (map_name == NULL || map_name[0] == '\0') {
1092 		pr_warning("map #%d: empty name.\n", var_idx);
1093 		return -EINVAL;
1094 	}
1095 	if ((__u64)vi->offset + vi->size > data->d_size) {
1096 		pr_warning("map '%s' BTF data is corrupted.\n", map_name);
1097 		return -EINVAL;
1098 	}
1099 	if (!btf_is_var(var)) {
1100 		pr_warning("map '%s': unexpected var kind %u.\n",
1101 			   map_name, btf_kind(var));
1102 		return -EINVAL;
1103 	}
1104 	if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
1105 	    var_extra->linkage != BTF_VAR_STATIC) {
1106 		pr_warning("map '%s': unsupported var linkage %u.\n",
1107 			   map_name, var_extra->linkage);
1108 		return -EOPNOTSUPP;
1109 	}
1110 
1111 	def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
1112 	if (!btf_is_struct(def)) {
1113 		pr_warning("map '%s': unexpected def kind %u.\n",
1114 			   map_name, btf_kind(var));
1115 		return -EINVAL;
1116 	}
1117 	if (def->size > vi->size) {
1118 		pr_warning("map '%s': invalid def size.\n", map_name);
1119 		return -EINVAL;
1120 	}
1121 
1122 	map = bpf_object__add_map(obj);
1123 	if (IS_ERR(map))
1124 		return PTR_ERR(map);
1125 	map->name = strdup(map_name);
1126 	if (!map->name) {
1127 		pr_warning("map '%s': failed to alloc map name.\n", map_name);
1128 		return -ENOMEM;
1129 	}
1130 	map->libbpf_type = LIBBPF_MAP_UNSPEC;
1131 	map->def.type = BPF_MAP_TYPE_UNSPEC;
1132 	map->sec_idx = sec_idx;
1133 	map->sec_offset = vi->offset;
1134 	pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
1135 		 map_name, map->sec_idx, map->sec_offset);
1136 
1137 	vlen = btf_vlen(def);
1138 	m = btf_members(def);
1139 	for (i = 0; i < vlen; i++, m++) {
1140 		const char *name = btf__name_by_offset(obj->btf, m->name_off);
1141 
1142 		if (!name) {
1143 			pr_warning("map '%s': invalid field #%d.\n",
1144 				   map_name, i);
1145 			return -EINVAL;
1146 		}
1147 		if (strcmp(name, "type") == 0) {
1148 			if (!get_map_field_int(map_name, obj->btf, def, m,
1149 					       &map->def.type))
1150 				return -EINVAL;
1151 			pr_debug("map '%s': found type = %u.\n",
1152 				 map_name, map->def.type);
1153 		} else if (strcmp(name, "max_entries") == 0) {
1154 			if (!get_map_field_int(map_name, obj->btf, def, m,
1155 					       &map->def.max_entries))
1156 				return -EINVAL;
1157 			pr_debug("map '%s': found max_entries = %u.\n",
1158 				 map_name, map->def.max_entries);
1159 		} else if (strcmp(name, "map_flags") == 0) {
1160 			if (!get_map_field_int(map_name, obj->btf, def, m,
1161 					       &map->def.map_flags))
1162 				return -EINVAL;
1163 			pr_debug("map '%s': found map_flags = %u.\n",
1164 				 map_name, map->def.map_flags);
1165 		} else if (strcmp(name, "key_size") == 0) {
1166 			__u32 sz;
1167 
1168 			if (!get_map_field_int(map_name, obj->btf, def, m,
1169 					       &sz))
1170 				return -EINVAL;
1171 			pr_debug("map '%s': found key_size = %u.\n",
1172 				 map_name, sz);
1173 			if (map->def.key_size && map->def.key_size != sz) {
1174 				pr_warning("map '%s': conflicting key size %u != %u.\n",
1175 					   map_name, map->def.key_size, sz);
1176 				return -EINVAL;
1177 			}
1178 			map->def.key_size = sz;
1179 		} else if (strcmp(name, "key") == 0) {
1180 			__s64 sz;
1181 
1182 			t = btf__type_by_id(obj->btf, m->type);
1183 			if (!t) {
1184 				pr_warning("map '%s': key type [%d] not found.\n",
1185 					   map_name, m->type);
1186 				return -EINVAL;
1187 			}
1188 			if (!btf_is_ptr(t)) {
1189 				pr_warning("map '%s': key spec is not PTR: %u.\n",
1190 					   map_name, btf_kind(t));
1191 				return -EINVAL;
1192 			}
1193 			sz = btf__resolve_size(obj->btf, t->type);
1194 			if (sz < 0) {
1195 				pr_warning("map '%s': can't determine key size for type [%u]: %lld.\n",
1196 					   map_name, t->type, sz);
1197 				return sz;
1198 			}
1199 			pr_debug("map '%s': found key [%u], sz = %lld.\n",
1200 				 map_name, t->type, sz);
1201 			if (map->def.key_size && map->def.key_size != sz) {
1202 				pr_warning("map '%s': conflicting key size %u != %lld.\n",
1203 					   map_name, map->def.key_size, sz);
1204 				return -EINVAL;
1205 			}
1206 			map->def.key_size = sz;
1207 			map->btf_key_type_id = t->type;
1208 		} else if (strcmp(name, "value_size") == 0) {
1209 			__u32 sz;
1210 
1211 			if (!get_map_field_int(map_name, obj->btf, def, m,
1212 					       &sz))
1213 				return -EINVAL;
1214 			pr_debug("map '%s': found value_size = %u.\n",
1215 				 map_name, sz);
1216 			if (map->def.value_size && map->def.value_size != sz) {
1217 				pr_warning("map '%s': conflicting value size %u != %u.\n",
1218 					   map_name, map->def.value_size, sz);
1219 				return -EINVAL;
1220 			}
1221 			map->def.value_size = sz;
1222 		} else if (strcmp(name, "value") == 0) {
1223 			__s64 sz;
1224 
1225 			t = btf__type_by_id(obj->btf, m->type);
1226 			if (!t) {
1227 				pr_warning("map '%s': value type [%d] not found.\n",
1228 					   map_name, m->type);
1229 				return -EINVAL;
1230 			}
1231 			if (!btf_is_ptr(t)) {
1232 				pr_warning("map '%s': value spec is not PTR: %u.\n",
1233 					   map_name, btf_kind(t));
1234 				return -EINVAL;
1235 			}
1236 			sz = btf__resolve_size(obj->btf, t->type);
1237 			if (sz < 0) {
1238 				pr_warning("map '%s': can't determine value size for type [%u]: %lld.\n",
1239 					   map_name, t->type, sz);
1240 				return sz;
1241 			}
1242 			pr_debug("map '%s': found value [%u], sz = %lld.\n",
1243 				 map_name, t->type, sz);
1244 			if (map->def.value_size && map->def.value_size != sz) {
1245 				pr_warning("map '%s': conflicting value size %u != %lld.\n",
1246 					   map_name, map->def.value_size, sz);
1247 				return -EINVAL;
1248 			}
1249 			map->def.value_size = sz;
1250 			map->btf_value_type_id = t->type;
1251 		} else {
1252 			if (strict) {
1253 				pr_warning("map '%s': unknown field '%s'.\n",
1254 					   map_name, name);
1255 				return -ENOTSUP;
1256 			}
1257 			pr_debug("map '%s': ignoring unknown field '%s'.\n",
1258 				 map_name, name);
1259 		}
1260 	}
1261 
1262 	if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
1263 		pr_warning("map '%s': map type isn't specified.\n", map_name);
1264 		return -EINVAL;
1265 	}
1266 
1267 	return 0;
1268 }
1269 
bpf_object__init_user_btf_maps(struct bpf_object * obj,bool strict)1270 static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
1271 {
1272 	const struct btf_type *sec = NULL;
1273 	int nr_types, i, vlen, err;
1274 	const struct btf_type *t;
1275 	const char *name;
1276 	Elf_Data *data;
1277 	Elf_Scn *scn;
1278 
1279 	if (obj->efile.btf_maps_shndx < 0)
1280 		return 0;
1281 
1282 	scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
1283 	if (scn)
1284 		data = elf_getdata(scn, NULL);
1285 	if (!scn || !data) {
1286 		pr_warning("failed to get Elf_Data from map section %d (%s)\n",
1287 			   obj->efile.maps_shndx, MAPS_ELF_SEC);
1288 		return -EINVAL;
1289 	}
1290 
1291 	nr_types = btf__get_nr_types(obj->btf);
1292 	for (i = 1; i <= nr_types; i++) {
1293 		t = btf__type_by_id(obj->btf, i);
1294 		if (!btf_is_datasec(t))
1295 			continue;
1296 		name = btf__name_by_offset(obj->btf, t->name_off);
1297 		if (strcmp(name, MAPS_ELF_SEC) == 0) {
1298 			sec = t;
1299 			break;
1300 		}
1301 	}
1302 
1303 	if (!sec) {
1304 		pr_warning("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
1305 		return -ENOENT;
1306 	}
1307 
1308 	vlen = btf_vlen(sec);
1309 	for (i = 0; i < vlen; i++) {
1310 		err = bpf_object__init_user_btf_map(obj, sec, i,
1311 						    obj->efile.btf_maps_shndx,
1312 						    data, strict);
1313 		if (err)
1314 			return err;
1315 	}
1316 
1317 	return 0;
1318 }
1319 
bpf_object__init_maps(struct bpf_object * obj,int flags)1320 static int bpf_object__init_maps(struct bpf_object *obj, int flags)
1321 {
1322 	bool strict = !(flags & MAPS_RELAX_COMPAT);
1323 	int err;
1324 
1325 	err = bpf_object__init_user_maps(obj, strict);
1326 	if (err)
1327 		return err;
1328 
1329 	err = bpf_object__init_user_btf_maps(obj, strict);
1330 	if (err)
1331 		return err;
1332 
1333 	err = bpf_object__init_global_data_maps(obj);
1334 	if (err)
1335 		return err;
1336 
1337 	if (obj->nr_maps) {
1338 		qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
1339 		      compare_bpf_map);
1340 	}
1341 	return 0;
1342 }
1343 
section_have_execinstr(struct bpf_object * obj,int idx)1344 static bool section_have_execinstr(struct bpf_object *obj, int idx)
1345 {
1346 	Elf_Scn *scn;
1347 	GElf_Shdr sh;
1348 
1349 	scn = elf_getscn(obj->efile.elf, idx);
1350 	if (!scn)
1351 		return false;
1352 
1353 	if (gelf_getshdr(scn, &sh) != &sh)
1354 		return false;
1355 
1356 	if (sh.sh_flags & SHF_EXECINSTR)
1357 		return true;
1358 
1359 	return false;
1360 }
1361 
bpf_object__sanitize_btf(struct bpf_object * obj)1362 static void bpf_object__sanitize_btf(struct bpf_object *obj)
1363 {
1364 	bool has_datasec = obj->caps.btf_datasec;
1365 	bool has_func = obj->caps.btf_func;
1366 	struct btf *btf = obj->btf;
1367 	struct btf_type *t;
1368 	int i, j, vlen;
1369 
1370 	if (!obj->btf || (has_func && has_datasec))
1371 		return;
1372 
1373 	for (i = 1; i <= btf__get_nr_types(btf); i++) {
1374 		t = (struct btf_type *)btf__type_by_id(btf, i);
1375 
1376 		if (!has_datasec && btf_is_var(t)) {
1377 			/* replace VAR with INT */
1378 			t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
1379 			/*
1380 			 * using size = 1 is the safest choice, 4 will be too
1381 			 * big and cause kernel BTF validation failure if
1382 			 * original variable took less than 4 bytes
1383 			 */
1384 			t->size = 1;
1385 			*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
1386 		} else if (!has_datasec && btf_is_datasec(t)) {
1387 			/* replace DATASEC with STRUCT */
1388 			const struct btf_var_secinfo *v = btf_var_secinfos(t);
1389 			struct btf_member *m = btf_members(t);
1390 			struct btf_type *vt;
1391 			char *name;
1392 
1393 			name = (char *)btf__name_by_offset(btf, t->name_off);
1394 			while (*name) {
1395 				if (*name == '.')
1396 					*name = '_';
1397 				name++;
1398 			}
1399 
1400 			vlen = btf_vlen(t);
1401 			t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
1402 			for (j = 0; j < vlen; j++, v++, m++) {
1403 				/* order of field assignments is important */
1404 				m->offset = v->offset * 8;
1405 				m->type = v->type;
1406 				/* preserve variable name as member name */
1407 				vt = (void *)btf__type_by_id(btf, v->type);
1408 				m->name_off = vt->name_off;
1409 			}
1410 		} else if (!has_func && btf_is_func_proto(t)) {
1411 			/* replace FUNC_PROTO with ENUM */
1412 			vlen = btf_vlen(t);
1413 			t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
1414 			t->size = sizeof(__u32); /* kernel enforced */
1415 		} else if (!has_func && btf_is_func(t)) {
1416 			/* replace FUNC with TYPEDEF */
1417 			t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
1418 		}
1419 	}
1420 }
1421 
bpf_object__sanitize_btf_ext(struct bpf_object * obj)1422 static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
1423 {
1424 	if (!obj->btf_ext)
1425 		return;
1426 
1427 	if (!obj->caps.btf_func) {
1428 		btf_ext__free(obj->btf_ext);
1429 		obj->btf_ext = NULL;
1430 	}
1431 }
1432 
bpf_object__is_btf_mandatory(const struct bpf_object * obj)1433 static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
1434 {
1435 	return obj->efile.btf_maps_shndx >= 0;
1436 }
1437 
bpf_object__init_btf(struct bpf_object * obj,Elf_Data * btf_data,Elf_Data * btf_ext_data)1438 static int bpf_object__init_btf(struct bpf_object *obj,
1439 				Elf_Data *btf_data,
1440 				Elf_Data *btf_ext_data)
1441 {
1442 	bool btf_required = bpf_object__is_btf_mandatory(obj);
1443 	int err = 0;
1444 
1445 	if (btf_data) {
1446 		obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
1447 		if (IS_ERR(obj->btf)) {
1448 			pr_warning("Error loading ELF section %s: %d.\n",
1449 				   BTF_ELF_SEC, err);
1450 			goto out;
1451 		}
1452 		err = btf__finalize_data(obj, obj->btf);
1453 		if (err) {
1454 			pr_warning("Error finalizing %s: %d.\n",
1455 				   BTF_ELF_SEC, err);
1456 			goto out;
1457 		}
1458 	}
1459 	if (btf_ext_data) {
1460 		if (!obj->btf) {
1461 			pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
1462 				 BTF_EXT_ELF_SEC, BTF_ELF_SEC);
1463 			goto out;
1464 		}
1465 		obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
1466 					    btf_ext_data->d_size);
1467 		if (IS_ERR(obj->btf_ext)) {
1468 			pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
1469 				   BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
1470 			obj->btf_ext = NULL;
1471 			goto out;
1472 		}
1473 	}
1474 out:
1475 	if (err || IS_ERR(obj->btf)) {
1476 		if (btf_required)
1477 			err = err ? : PTR_ERR(obj->btf);
1478 		else
1479 			err = 0;
1480 		if (!IS_ERR_OR_NULL(obj->btf))
1481 			btf__free(obj->btf);
1482 		obj->btf = NULL;
1483 	}
1484 	if (btf_required && !obj->btf) {
1485 		pr_warning("BTF is required, but is missing or corrupted.\n");
1486 		return err == 0 ? -ENOENT : err;
1487 	}
1488 	return 0;
1489 }
1490 
bpf_object__sanitize_and_load_btf(struct bpf_object * obj)1491 static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
1492 {
1493 	int err = 0;
1494 
1495 	if (!obj->btf)
1496 		return 0;
1497 
1498 	bpf_object__sanitize_btf(obj);
1499 	bpf_object__sanitize_btf_ext(obj);
1500 
1501 	err = btf__load(obj->btf);
1502 	if (err) {
1503 		pr_warning("Error loading %s into kernel: %d.\n",
1504 			   BTF_ELF_SEC, err);
1505 		btf__free(obj->btf);
1506 		obj->btf = NULL;
1507 		/* btf_ext can't exist without btf, so free it as well */
1508 		if (obj->btf_ext) {
1509 			btf_ext__free(obj->btf_ext);
1510 			obj->btf_ext = NULL;
1511 		}
1512 
1513 		if (bpf_object__is_btf_mandatory(obj))
1514 			return err;
1515 	}
1516 	return 0;
1517 }
1518 
bpf_object__elf_collect(struct bpf_object * obj,int flags)1519 static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
1520 {
1521 	Elf *elf = obj->efile.elf;
1522 	GElf_Ehdr *ep = &obj->efile.ehdr;
1523 	Elf_Data *btf_ext_data = NULL;
1524 	Elf_Data *btf_data = NULL;
1525 	Elf_Scn *scn = NULL;
1526 	int idx = 0, err = 0;
1527 
1528 	/* Elf is corrupted/truncated, avoid calling elf_strptr. */
1529 	if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
1530 		pr_warning("failed to get e_shstrndx from %s\n", obj->path);
1531 		return -LIBBPF_ERRNO__FORMAT;
1532 	}
1533 
1534 	while ((scn = elf_nextscn(elf, scn)) != NULL) {
1535 		char *name;
1536 		GElf_Shdr sh;
1537 		Elf_Data *data;
1538 
1539 		idx++;
1540 		if (gelf_getshdr(scn, &sh) != &sh) {
1541 			pr_warning("failed to get section(%d) header from %s\n",
1542 				   idx, obj->path);
1543 			return -LIBBPF_ERRNO__FORMAT;
1544 		}
1545 
1546 		name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
1547 		if (!name) {
1548 			pr_warning("failed to get section(%d) name from %s\n",
1549 				   idx, obj->path);
1550 			return -LIBBPF_ERRNO__FORMAT;
1551 		}
1552 
1553 		data = elf_getdata(scn, 0);
1554 		if (!data) {
1555 			pr_warning("failed to get section(%d) data from %s(%s)\n",
1556 				   idx, name, obj->path);
1557 			return -LIBBPF_ERRNO__FORMAT;
1558 		}
1559 		pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
1560 			 idx, name, (unsigned long)data->d_size,
1561 			 (int)sh.sh_link, (unsigned long)sh.sh_flags,
1562 			 (int)sh.sh_type);
1563 
1564 		if (strcmp(name, "license") == 0) {
1565 			err = bpf_object__init_license(obj,
1566 						       data->d_buf,
1567 						       data->d_size);
1568 			if (err)
1569 				return err;
1570 		} else if (strcmp(name, "version") == 0) {
1571 			err = bpf_object__init_kversion(obj,
1572 							data->d_buf,
1573 							data->d_size);
1574 			if (err)
1575 				return err;
1576 		} else if (strcmp(name, "maps") == 0) {
1577 			obj->efile.maps_shndx = idx;
1578 		} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
1579 			obj->efile.btf_maps_shndx = idx;
1580 		} else if (strcmp(name, BTF_ELF_SEC) == 0) {
1581 			btf_data = data;
1582 		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
1583 			btf_ext_data = data;
1584 		} else if (sh.sh_type == SHT_SYMTAB) {
1585 			if (obj->efile.symbols) {
1586 				pr_warning("bpf: multiple SYMTAB in %s\n",
1587 					   obj->path);
1588 				return -LIBBPF_ERRNO__FORMAT;
1589 			}
1590 			obj->efile.symbols = data;
1591 			obj->efile.strtabidx = sh.sh_link;
1592 		} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
1593 			if (sh.sh_flags & SHF_EXECINSTR) {
1594 				if (strcmp(name, ".text") == 0)
1595 					obj->efile.text_shndx = idx;
1596 				err = bpf_object__add_program(obj, data->d_buf,
1597 							      data->d_size, name, idx);
1598 				if (err) {
1599 					char errmsg[STRERR_BUFSIZE];
1600 					char *cp = libbpf_strerror_r(-err, errmsg,
1601 								     sizeof(errmsg));
1602 
1603 					pr_warning("failed to alloc program %s (%s): %s",
1604 						   name, obj->path, cp);
1605 					return err;
1606 				}
1607 			} else if (strcmp(name, ".data") == 0) {
1608 				obj->efile.data = data;
1609 				obj->efile.data_shndx = idx;
1610 			} else if (strcmp(name, ".rodata") == 0) {
1611 				obj->efile.rodata = data;
1612 				obj->efile.rodata_shndx = idx;
1613 			} else {
1614 				pr_debug("skip section(%d) %s\n", idx, name);
1615 			}
1616 		} else if (sh.sh_type == SHT_REL) {
1617 			int nr_reloc = obj->efile.nr_reloc;
1618 			void *reloc = obj->efile.reloc;
1619 			int sec = sh.sh_info; /* points to other section */
1620 
1621 			/* Only do relo for section with exec instructions */
1622 			if (!section_have_execinstr(obj, sec)) {
1623 				pr_debug("skip relo %s(%d) for section(%d)\n",
1624 					 name, idx, sec);
1625 				continue;
1626 			}
1627 
1628 			reloc = reallocarray(reloc, nr_reloc + 1,
1629 					     sizeof(*obj->efile.reloc));
1630 			if (!reloc) {
1631 				pr_warning("realloc failed\n");
1632 				return -ENOMEM;
1633 			}
1634 
1635 			obj->efile.reloc = reloc;
1636 			obj->efile.nr_reloc++;
1637 
1638 			obj->efile.reloc[nr_reloc].shdr = sh;
1639 			obj->efile.reloc[nr_reloc].data = data;
1640 		} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
1641 			obj->efile.bss = data;
1642 			obj->efile.bss_shndx = idx;
1643 		} else {
1644 			pr_debug("skip section(%d) %s\n", idx, name);
1645 		}
1646 	}
1647 
1648 	if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
1649 		pr_warning("Corrupted ELF file: index of strtab invalid\n");
1650 		return -LIBBPF_ERRNO__FORMAT;
1651 	}
1652 	err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
1653 	if (!err)
1654 		err = bpf_object__init_maps(obj, flags);
1655 	if (!err)
1656 		err = bpf_object__sanitize_and_load_btf(obj);
1657 	if (!err)
1658 		err = bpf_object__init_prog_names(obj);
1659 	return err;
1660 }
1661 
1662 static struct bpf_program *
bpf_object__find_prog_by_idx(struct bpf_object * obj,int idx)1663 bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
1664 {
1665 	struct bpf_program *prog;
1666 	size_t i;
1667 
1668 	for (i = 0; i < obj->nr_programs; i++) {
1669 		prog = &obj->programs[i];
1670 		if (prog->idx == idx)
1671 			return prog;
1672 	}
1673 	return NULL;
1674 }
1675 
1676 struct bpf_program *
bpf_object__find_program_by_title(const struct bpf_object * obj,const char * title)1677 bpf_object__find_program_by_title(const struct bpf_object *obj,
1678 				  const char *title)
1679 {
1680 	struct bpf_program *pos;
1681 
1682 	bpf_object__for_each_program(pos, obj) {
1683 		if (pos->section_name && !strcmp(pos->section_name, title))
1684 			return pos;
1685 	}
1686 	return NULL;
1687 }
1688 
bpf_object__shndx_is_data(const struct bpf_object * obj,int shndx)1689 static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
1690 				      int shndx)
1691 {
1692 	return shndx == obj->efile.data_shndx ||
1693 	       shndx == obj->efile.bss_shndx ||
1694 	       shndx == obj->efile.rodata_shndx;
1695 }
1696 
bpf_object__shndx_is_maps(const struct bpf_object * obj,int shndx)1697 static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
1698 				      int shndx)
1699 {
1700 	return shndx == obj->efile.maps_shndx ||
1701 	       shndx == obj->efile.btf_maps_shndx;
1702 }
1703 
bpf_object__relo_in_known_section(const struct bpf_object * obj,int shndx)1704 static bool bpf_object__relo_in_known_section(const struct bpf_object *obj,
1705 					      int shndx)
1706 {
1707 	return shndx == obj->efile.text_shndx ||
1708 	       bpf_object__shndx_is_maps(obj, shndx) ||
1709 	       bpf_object__shndx_is_data(obj, shndx);
1710 }
1711 
1712 static enum libbpf_map_type
bpf_object__section_to_libbpf_map_type(const struct bpf_object * obj,int shndx)1713 bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
1714 {
1715 	if (shndx == obj->efile.data_shndx)
1716 		return LIBBPF_MAP_DATA;
1717 	else if (shndx == obj->efile.bss_shndx)
1718 		return LIBBPF_MAP_BSS;
1719 	else if (shndx == obj->efile.rodata_shndx)
1720 		return LIBBPF_MAP_RODATA;
1721 	else
1722 		return LIBBPF_MAP_UNSPEC;
1723 }
1724 
1725 static int
bpf_program__collect_reloc(struct bpf_program * prog,GElf_Shdr * shdr,Elf_Data * data,struct bpf_object * obj)1726 bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
1727 			   Elf_Data *data, struct bpf_object *obj)
1728 {
1729 	Elf_Data *symbols = obj->efile.symbols;
1730 	struct bpf_map *maps = obj->maps;
1731 	size_t nr_maps = obj->nr_maps;
1732 	int i, nrels;
1733 
1734 	pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
1735 	nrels = shdr->sh_size / shdr->sh_entsize;
1736 
1737 	prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
1738 	if (!prog->reloc_desc) {
1739 		pr_warning("failed to alloc memory in relocation\n");
1740 		return -ENOMEM;
1741 	}
1742 	prog->nr_reloc = nrels;
1743 
1744 	for (i = 0; i < nrels; i++) {
1745 		struct bpf_insn *insns = prog->insns;
1746 		enum libbpf_map_type type;
1747 		unsigned int insn_idx;
1748 		unsigned int shdr_idx;
1749 		const char *name;
1750 		size_t map_idx;
1751 		GElf_Sym sym;
1752 		GElf_Rel rel;
1753 
1754 		if (!gelf_getrel(data, i, &rel)) {
1755 			pr_warning("relocation: failed to get %d reloc\n", i);
1756 			return -LIBBPF_ERRNO__FORMAT;
1757 		}
1758 
1759 		if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
1760 			pr_warning("relocation: symbol %"PRIx64" not found\n",
1761 				   GELF_R_SYM(rel.r_info));
1762 			return -LIBBPF_ERRNO__FORMAT;
1763 		}
1764 
1765 		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
1766 				  sym.st_name) ? : "<?>";
1767 
1768 		pr_debug("relo for %lld value %lld name %d (\'%s\')\n",
1769 			 (long long) (rel.r_info >> 32),
1770 			 (long long) sym.st_value, sym.st_name, name);
1771 
1772 		shdr_idx = sym.st_shndx;
1773 		insn_idx = rel.r_offset / sizeof(struct bpf_insn);
1774 		pr_debug("relocation: insn_idx=%u, shdr_idx=%u\n",
1775 			 insn_idx, shdr_idx);
1776 
1777 		if (shdr_idx >= SHN_LORESERVE) {
1778 			pr_warning("relocation: not yet supported relo for non-static global \'%s\' variable in special section (0x%x) found in insns[%d].code 0x%x\n",
1779 				   name, shdr_idx, insn_idx,
1780 				   insns[insn_idx].code);
1781 			return -LIBBPF_ERRNO__RELOC;
1782 		}
1783 		if (!bpf_object__relo_in_known_section(obj, shdr_idx)) {
1784 			pr_warning("Program '%s' contains unrecognized relo data pointing to section %u\n",
1785 				   prog->section_name, shdr_idx);
1786 			return -LIBBPF_ERRNO__RELOC;
1787 		}
1788 
1789 		if (insns[insn_idx].code == (BPF_JMP | BPF_CALL)) {
1790 			if (insns[insn_idx].src_reg != BPF_PSEUDO_CALL) {
1791 				pr_warning("incorrect bpf_call opcode\n");
1792 				return -LIBBPF_ERRNO__RELOC;
1793 			}
1794 			prog->reloc_desc[i].type = RELO_CALL;
1795 			prog->reloc_desc[i].insn_idx = insn_idx;
1796 			prog->reloc_desc[i].text_off = sym.st_value;
1797 			obj->has_pseudo_calls = true;
1798 			continue;
1799 		}
1800 
1801 		if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
1802 			pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
1803 				   insn_idx, insns[insn_idx].code);
1804 			return -LIBBPF_ERRNO__RELOC;
1805 		}
1806 
1807 		if (bpf_object__shndx_is_maps(obj, shdr_idx) ||
1808 		    bpf_object__shndx_is_data(obj, shdr_idx)) {
1809 			type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
1810 			if (type != LIBBPF_MAP_UNSPEC) {
1811 				if (GELF_ST_BIND(sym.st_info) == STB_GLOBAL) {
1812 					pr_warning("bpf: relocation: not yet supported relo for non-static global \'%s\' variable found in insns[%d].code 0x%x\n",
1813 						   name, insn_idx, insns[insn_idx].code);
1814 					return -LIBBPF_ERRNO__RELOC;
1815 				}
1816 				if (!obj->caps.global_data) {
1817 					pr_warning("bpf: relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
1818 						   name, insn_idx);
1819 					return -LIBBPF_ERRNO__RELOC;
1820 				}
1821 			}
1822 
1823 			for (map_idx = 0; map_idx < nr_maps; map_idx++) {
1824 				if (maps[map_idx].libbpf_type != type)
1825 					continue;
1826 				if (type != LIBBPF_MAP_UNSPEC ||
1827 				    (maps[map_idx].sec_idx == sym.st_shndx &&
1828 				     maps[map_idx].sec_offset == sym.st_value)) {
1829 					pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n",
1830 						 map_idx, maps[map_idx].name,
1831 						 maps[map_idx].sec_idx,
1832 						 maps[map_idx].sec_offset,
1833 						 insn_idx);
1834 					break;
1835 				}
1836 			}
1837 
1838 			if (map_idx >= nr_maps) {
1839 				pr_warning("bpf relocation: map_idx %d larger than %d\n",
1840 					   (int)map_idx, (int)nr_maps - 1);
1841 				return -LIBBPF_ERRNO__RELOC;
1842 			}
1843 
1844 			prog->reloc_desc[i].type = type != LIBBPF_MAP_UNSPEC ?
1845 						   RELO_DATA : RELO_LD64;
1846 			prog->reloc_desc[i].insn_idx = insn_idx;
1847 			prog->reloc_desc[i].map_idx = map_idx;
1848 		}
1849 	}
1850 	return 0;
1851 }
1852 
bpf_map_find_btf_info(struct bpf_object * obj,struct bpf_map * map)1853 static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
1854 {
1855 	struct bpf_map_def *def = &map->def;
1856 	__u32 key_type_id = 0, value_type_id = 0;
1857 	int ret;
1858 
1859 	/* if it's BTF-defined map, we don't need to search for type IDs */
1860 	if (map->sec_idx == obj->efile.btf_maps_shndx)
1861 		return 0;
1862 
1863 	if (!bpf_map__is_internal(map)) {
1864 		ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
1865 					   def->value_size, &key_type_id,
1866 					   &value_type_id);
1867 	} else {
1868 		/*
1869 		 * LLVM annotates global data differently in BTF, that is,
1870 		 * only as '.data', '.bss' or '.rodata'.
1871 		 */
1872 		ret = btf__find_by_name(obj->btf,
1873 				libbpf_type_to_btf_name[map->libbpf_type]);
1874 	}
1875 	if (ret < 0)
1876 		return ret;
1877 
1878 	map->btf_key_type_id = key_type_id;
1879 	map->btf_value_type_id = bpf_map__is_internal(map) ?
1880 				 ret : value_type_id;
1881 	return 0;
1882 }
1883 
bpf_map__reuse_fd(struct bpf_map * map,int fd)1884 int bpf_map__reuse_fd(struct bpf_map *map, int fd)
1885 {
1886 	struct bpf_map_info info = {};
1887 	__u32 len = sizeof(info);
1888 	int new_fd, err;
1889 	char *new_name;
1890 
1891 	err = bpf_obj_get_info_by_fd(fd, &info, &len);
1892 	if (err)
1893 		return err;
1894 
1895 	new_name = strdup(info.name);
1896 	if (!new_name)
1897 		return -errno;
1898 
1899 	new_fd = open("/", O_RDONLY | O_CLOEXEC);
1900 	if (new_fd < 0) {
1901 		err = -errno;
1902 		goto err_free_new_name;
1903 	}
1904 
1905 	new_fd = dup3(fd, new_fd, O_CLOEXEC);
1906 	if (new_fd < 0) {
1907 		err = -errno;
1908 		goto err_close_new_fd;
1909 	}
1910 
1911 	err = zclose(map->fd);
1912 	if (err) {
1913 		err = -errno;
1914 		goto err_close_new_fd;
1915 	}
1916 	free(map->name);
1917 
1918 	map->fd = new_fd;
1919 	map->name = new_name;
1920 	map->def.type = info.type;
1921 	map->def.key_size = info.key_size;
1922 	map->def.value_size = info.value_size;
1923 	map->def.max_entries = info.max_entries;
1924 	map->def.map_flags = info.map_flags;
1925 	map->btf_key_type_id = info.btf_key_type_id;
1926 	map->btf_value_type_id = info.btf_value_type_id;
1927 
1928 	return 0;
1929 
1930 err_close_new_fd:
1931 	close(new_fd);
1932 err_free_new_name:
1933 	free(new_name);
1934 	return err;
1935 }
1936 
bpf_map__resize(struct bpf_map * map,__u32 max_entries)1937 int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
1938 {
1939 	if (!map || !max_entries)
1940 		return -EINVAL;
1941 
1942 	/* If map already created, its attributes can't be changed. */
1943 	if (map->fd >= 0)
1944 		return -EBUSY;
1945 
1946 	map->def.max_entries = max_entries;
1947 
1948 	return 0;
1949 }
1950 
1951 static int
bpf_object__probe_name(struct bpf_object * obj)1952 bpf_object__probe_name(struct bpf_object *obj)
1953 {
1954 	struct bpf_load_program_attr attr;
1955 	char *cp, errmsg[STRERR_BUFSIZE];
1956 	struct bpf_insn insns[] = {
1957 		BPF_MOV64_IMM(BPF_REG_0, 0),
1958 		BPF_EXIT_INSN(),
1959 	};
1960 	int ret;
1961 
1962 	/* make sure basic loading works */
1963 
1964 	memset(&attr, 0, sizeof(attr));
1965 	attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
1966 	attr.insns = insns;
1967 	attr.insns_cnt = ARRAY_SIZE(insns);
1968 	attr.license = "GPL";
1969 
1970 	ret = bpf_load_program_xattr(&attr, NULL, 0);
1971 	if (ret < 0) {
1972 		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
1973 		pr_warning("Error in %s():%s(%d). Couldn't load basic 'r0 = 0' BPF program.\n",
1974 			   __func__, cp, errno);
1975 		return -errno;
1976 	}
1977 	close(ret);
1978 
1979 	/* now try the same program, but with the name */
1980 
1981 	attr.name = "test";
1982 	ret = bpf_load_program_xattr(&attr, NULL, 0);
1983 	if (ret >= 0) {
1984 		obj->caps.name = 1;
1985 		close(ret);
1986 	}
1987 
1988 	return 0;
1989 }
1990 
1991 static int
bpf_object__probe_global_data(struct bpf_object * obj)1992 bpf_object__probe_global_data(struct bpf_object *obj)
1993 {
1994 	struct bpf_load_program_attr prg_attr;
1995 	struct bpf_create_map_attr map_attr;
1996 	char *cp, errmsg[STRERR_BUFSIZE];
1997 	struct bpf_insn insns[] = {
1998 		BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
1999 		BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
2000 		BPF_MOV64_IMM(BPF_REG_0, 0),
2001 		BPF_EXIT_INSN(),
2002 	};
2003 	int ret, map;
2004 
2005 	memset(&map_attr, 0, sizeof(map_attr));
2006 	map_attr.map_type = BPF_MAP_TYPE_ARRAY;
2007 	map_attr.key_size = sizeof(int);
2008 	map_attr.value_size = 32;
2009 	map_attr.max_entries = 1;
2010 
2011 	map = bpf_create_map_xattr(&map_attr);
2012 	if (map < 0) {
2013 		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
2014 		pr_warning("Error in %s():%s(%d). Couldn't create simple array map.\n",
2015 			   __func__, cp, errno);
2016 		return -errno;
2017 	}
2018 
2019 	insns[0].imm = map;
2020 
2021 	memset(&prg_attr, 0, sizeof(prg_attr));
2022 	prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
2023 	prg_attr.insns = insns;
2024 	prg_attr.insns_cnt = ARRAY_SIZE(insns);
2025 	prg_attr.license = "GPL";
2026 
2027 	ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
2028 	if (ret >= 0) {
2029 		obj->caps.global_data = 1;
2030 		close(ret);
2031 	}
2032 
2033 	close(map);
2034 	return 0;
2035 }
2036 
bpf_object__probe_btf_func(struct bpf_object * obj)2037 static int bpf_object__probe_btf_func(struct bpf_object *obj)
2038 {
2039 	const char strs[] = "\0int\0x\0a";
2040 	/* void x(int a) {} */
2041 	__u32 types[] = {
2042 		/* int */
2043 		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
2044 		/* FUNC_PROTO */                                /* [2] */
2045 		BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
2046 		BTF_PARAM_ENC(7, 1),
2047 		/* FUNC x */                                    /* [3] */
2048 		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
2049 	};
2050 	int btf_fd;
2051 
2052 	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
2053 				      strs, sizeof(strs));
2054 	if (btf_fd >= 0) {
2055 		obj->caps.btf_func = 1;
2056 		close(btf_fd);
2057 		return 1;
2058 	}
2059 
2060 	return 0;
2061 }
2062 
bpf_object__probe_btf_datasec(struct bpf_object * obj)2063 static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
2064 {
2065 	const char strs[] = "\0x\0.data";
2066 	/* static int a; */
2067 	__u32 types[] = {
2068 		/* int */
2069 		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
2070 		/* VAR x */                                     /* [2] */
2071 		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
2072 		BTF_VAR_STATIC,
2073 		/* DATASEC val */                               /* [3] */
2074 		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
2075 		BTF_VAR_SECINFO_ENC(2, 0, 4),
2076 	};
2077 	int btf_fd;
2078 
2079 	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
2080 				      strs, sizeof(strs));
2081 	if (btf_fd >= 0) {
2082 		obj->caps.btf_datasec = 1;
2083 		close(btf_fd);
2084 		return 1;
2085 	}
2086 
2087 	return 0;
2088 }
2089 
2090 static int
bpf_object__probe_caps(struct bpf_object * obj)2091 bpf_object__probe_caps(struct bpf_object *obj)
2092 {
2093 	int (*probe_fn[])(struct bpf_object *obj) = {
2094 		bpf_object__probe_name,
2095 		bpf_object__probe_global_data,
2096 		bpf_object__probe_btf_func,
2097 		bpf_object__probe_btf_datasec,
2098 	};
2099 	int i, ret;
2100 
2101 	for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
2102 		ret = probe_fn[i](obj);
2103 		if (ret < 0)
2104 			pr_debug("Probe #%d failed with %d.\n", i, ret);
2105 	}
2106 
2107 	return 0;
2108 }
2109 
2110 static int
bpf_object__populate_internal_map(struct bpf_object * obj,struct bpf_map * map)2111 bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
2112 {
2113 	char *cp, errmsg[STRERR_BUFSIZE];
2114 	int err, zero = 0;
2115 	__u8 *data;
2116 
2117 	/* Nothing to do here since kernel already zero-initializes .bss map. */
2118 	if (map->libbpf_type == LIBBPF_MAP_BSS)
2119 		return 0;
2120 
2121 	data = map->libbpf_type == LIBBPF_MAP_DATA ?
2122 	       obj->sections.data : obj->sections.rodata;
2123 
2124 	err = bpf_map_update_elem(map->fd, &zero, data, 0);
2125 	/* Freeze .rodata map as read-only from syscall side. */
2126 	if (!err && map->libbpf_type == LIBBPF_MAP_RODATA) {
2127 		err = bpf_map_freeze(map->fd);
2128 		if (err) {
2129 			cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
2130 			pr_warning("Error freezing map(%s) as read-only: %s\n",
2131 				   map->name, cp);
2132 			err = 0;
2133 		}
2134 	}
2135 	return err;
2136 }
2137 
2138 static int
bpf_object__create_maps(struct bpf_object * obj)2139 bpf_object__create_maps(struct bpf_object *obj)
2140 {
2141 	struct bpf_create_map_attr create_attr = {};
2142 	int nr_cpus = 0;
2143 	unsigned int i;
2144 	int err;
2145 
2146 	for (i = 0; i < obj->nr_maps; i++) {
2147 		struct bpf_map *map = &obj->maps[i];
2148 		struct bpf_map_def *def = &map->def;
2149 		char *cp, errmsg[STRERR_BUFSIZE];
2150 		int *pfd = &map->fd;
2151 
2152 		if (map->fd >= 0) {
2153 			pr_debug("skip map create (preset) %s: fd=%d\n",
2154 				 map->name, map->fd);
2155 			continue;
2156 		}
2157 
2158 		if (obj->caps.name)
2159 			create_attr.name = map->name;
2160 		create_attr.map_ifindex = map->map_ifindex;
2161 		create_attr.map_type = def->type;
2162 		create_attr.map_flags = def->map_flags;
2163 		create_attr.key_size = def->key_size;
2164 		create_attr.value_size = def->value_size;
2165 		if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
2166 		    !def->max_entries) {
2167 			if (!nr_cpus)
2168 				nr_cpus = libbpf_num_possible_cpus();
2169 			if (nr_cpus < 0) {
2170 				pr_warning("failed to determine number of system CPUs: %d\n",
2171 					   nr_cpus);
2172 				err = nr_cpus;
2173 				goto err_out;
2174 			}
2175 			pr_debug("map '%s': setting size to %d\n",
2176 				 map->name, nr_cpus);
2177 			create_attr.max_entries = nr_cpus;
2178 		} else {
2179 			create_attr.max_entries = def->max_entries;
2180 		}
2181 		create_attr.btf_fd = 0;
2182 		create_attr.btf_key_type_id = 0;
2183 		create_attr.btf_value_type_id = 0;
2184 		if (bpf_map_type__is_map_in_map(def->type) &&
2185 		    map->inner_map_fd >= 0)
2186 			create_attr.inner_map_fd = map->inner_map_fd;
2187 
2188 		if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
2189 			create_attr.btf_fd = btf__fd(obj->btf);
2190 			create_attr.btf_key_type_id = map->btf_key_type_id;
2191 			create_attr.btf_value_type_id = map->btf_value_type_id;
2192 		}
2193 
2194 		*pfd = bpf_create_map_xattr(&create_attr);
2195 		if (*pfd < 0 && (create_attr.btf_key_type_id ||
2196 				 create_attr.btf_value_type_id)) {
2197 			err = -errno;
2198 			cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
2199 			pr_warning("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
2200 				   map->name, cp, err);
2201 			create_attr.btf_fd = 0;
2202 			create_attr.btf_key_type_id = 0;
2203 			create_attr.btf_value_type_id = 0;
2204 			map->btf_key_type_id = 0;
2205 			map->btf_value_type_id = 0;
2206 			*pfd = bpf_create_map_xattr(&create_attr);
2207 		}
2208 
2209 		if (*pfd < 0) {
2210 			size_t j;
2211 
2212 			err = -errno;
2213 err_out:
2214 			cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
2215 			pr_warning("failed to create map (name: '%s'): %s(%d)\n",
2216 				   map->name, cp, err);
2217 			for (j = 0; j < i; j++)
2218 				zclose(obj->maps[j].fd);
2219 			return err;
2220 		}
2221 
2222 		if (bpf_map__is_internal(map)) {
2223 			err = bpf_object__populate_internal_map(obj, map);
2224 			if (err < 0) {
2225 				zclose(*pfd);
2226 				goto err_out;
2227 			}
2228 		}
2229 
2230 		pr_debug("created map %s: fd=%d\n", map->name, *pfd);
2231 	}
2232 
2233 	return 0;
2234 }
2235 
2236 static int
check_btf_ext_reloc_err(struct bpf_program * prog,int err,void * btf_prog_info,const char * info_name)2237 check_btf_ext_reloc_err(struct bpf_program *prog, int err,
2238 			void *btf_prog_info, const char *info_name)
2239 {
2240 	if (err != -ENOENT) {
2241 		pr_warning("Error in loading %s for sec %s.\n",
2242 			   info_name, prog->section_name);
2243 		return err;
2244 	}
2245 
2246 	/* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */
2247 
2248 	if (btf_prog_info) {
2249 		/*
2250 		 * Some info has already been found but has problem
2251 		 * in the last btf_ext reloc. Must have to error out.
2252 		 */
2253 		pr_warning("Error in relocating %s for sec %s.\n",
2254 			   info_name, prog->section_name);
2255 		return err;
2256 	}
2257 
2258 	/* Have problem loading the very first info. Ignore the rest. */
2259 	pr_warning("Cannot find %s for main program sec %s. Ignore all %s.\n",
2260 		   info_name, prog->section_name, info_name);
2261 	return 0;
2262 }
2263 
2264 static int
bpf_program_reloc_btf_ext(struct bpf_program * prog,struct bpf_object * obj,const char * section_name,__u32 insn_offset)2265 bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj,
2266 			  const char *section_name,  __u32 insn_offset)
2267 {
2268 	int err;
2269 
2270 	if (!insn_offset || prog->func_info) {
2271 		/*
2272 		 * !insn_offset => main program
2273 		 *
2274 		 * For sub prog, the main program's func_info has to
2275 		 * be loaded first (i.e. prog->func_info != NULL)
2276 		 */
2277 		err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext,
2278 					       section_name, insn_offset,
2279 					       &prog->func_info,
2280 					       &prog->func_info_cnt);
2281 		if (err)
2282 			return check_btf_ext_reloc_err(prog, err,
2283 						       prog->func_info,
2284 						       "bpf_func_info");
2285 
2286 		prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext);
2287 	}
2288 
2289 	if (!insn_offset || prog->line_info) {
2290 		err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext,
2291 					       section_name, insn_offset,
2292 					       &prog->line_info,
2293 					       &prog->line_info_cnt);
2294 		if (err)
2295 			return check_btf_ext_reloc_err(prog, err,
2296 						       prog->line_info,
2297 						       "bpf_line_info");
2298 
2299 		prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext);
2300 	}
2301 
2302 	return 0;
2303 }
2304 
2305 #define BPF_CORE_SPEC_MAX_LEN 64
2306 
2307 /* represents BPF CO-RE field or array element accessor */
2308 struct bpf_core_accessor {
2309 	__u32 type_id;		/* struct/union type or array element type */
2310 	__u32 idx;		/* field index or array index */
2311 	const char *name;	/* field name or NULL for array accessor */
2312 };
2313 
2314 struct bpf_core_spec {
2315 	const struct btf *btf;
2316 	/* high-level spec: named fields and array indices only */
2317 	struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
2318 	/* high-level spec length */
2319 	int len;
2320 	/* raw, low-level spec: 1-to-1 with accessor spec string */
2321 	int raw_spec[BPF_CORE_SPEC_MAX_LEN];
2322 	/* raw spec length */
2323 	int raw_len;
2324 	/* field byte offset represented by spec */
2325 	__u32 offset;
2326 };
2327 
str_is_empty(const char * s)2328 static bool str_is_empty(const char *s)
2329 {
2330 	return !s || !s[0];
2331 }
2332 
2333 /*
2334  * Turn bpf_offset_reloc into a low- and high-level spec representation,
2335  * validating correctness along the way, as well as calculating resulting
2336  * field offset (in bytes), specified by accessor string. Low-level spec
2337  * captures every single level of nestedness, including traversing anonymous
2338  * struct/union members. High-level one only captures semantically meaningful
2339  * "turning points": named fields and array indicies.
2340  * E.g., for this case:
2341  *
2342  *   struct sample {
2343  *       int __unimportant;
2344  *       struct {
2345  *           int __1;
2346  *           int __2;
2347  *           int a[7];
2348  *       };
2349  *   };
2350  *
2351  *   struct sample *s = ...;
2352  *
2353  *   int x = &s->a[3]; // access string = '0:1:2:3'
2354  *
2355  * Low-level spec has 1:1 mapping with each element of access string (it's
2356  * just a parsed access string representation): [0, 1, 2, 3].
2357  *
2358  * High-level spec will capture only 3 points:
2359  *   - intial zero-index access by pointer (&s->... is the same as &s[0]...);
2360  *   - field 'a' access (corresponds to '2' in low-level spec);
2361  *   - array element #3 access (corresponds to '3' in low-level spec).
2362  *
2363  */
bpf_core_spec_parse(const struct btf * btf,__u32 type_id,const char * spec_str,struct bpf_core_spec * spec)2364 static int bpf_core_spec_parse(const struct btf *btf,
2365 			       __u32 type_id,
2366 			       const char *spec_str,
2367 			       struct bpf_core_spec *spec)
2368 {
2369 	int access_idx, parsed_len, i;
2370 	const struct btf_type *t;
2371 	const char *name;
2372 	__u32 id;
2373 	__s64 sz;
2374 
2375 	if (str_is_empty(spec_str) || *spec_str == ':')
2376 		return -EINVAL;
2377 
2378 	memset(spec, 0, sizeof(*spec));
2379 	spec->btf = btf;
2380 
2381 	/* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
2382 	while (*spec_str) {
2383 		if (*spec_str == ':')
2384 			++spec_str;
2385 		if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
2386 			return -EINVAL;
2387 		if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
2388 			return -E2BIG;
2389 		spec_str += parsed_len;
2390 		spec->raw_spec[spec->raw_len++] = access_idx;
2391 	}
2392 
2393 	if (spec->raw_len == 0)
2394 		return -EINVAL;
2395 
2396 	/* first spec value is always reloc type array index */
2397 	t = skip_mods_and_typedefs(btf, type_id, &id);
2398 	if (!t)
2399 		return -EINVAL;
2400 
2401 	access_idx = spec->raw_spec[0];
2402 	spec->spec[0].type_id = id;
2403 	spec->spec[0].idx = access_idx;
2404 	spec->len++;
2405 
2406 	sz = btf__resolve_size(btf, id);
2407 	if (sz < 0)
2408 		return sz;
2409 	spec->offset = access_idx * sz;
2410 
2411 	for (i = 1; i < spec->raw_len; i++) {
2412 		t = skip_mods_and_typedefs(btf, id, &id);
2413 		if (!t)
2414 			return -EINVAL;
2415 
2416 		access_idx = spec->raw_spec[i];
2417 
2418 		if (btf_is_composite(t)) {
2419 			const struct btf_member *m;
2420 			__u32 offset;
2421 
2422 			if (access_idx >= btf_vlen(t))
2423 				return -EINVAL;
2424 			if (btf_member_bitfield_size(t, access_idx))
2425 				return -EINVAL;
2426 
2427 			offset = btf_member_bit_offset(t, access_idx);
2428 			if (offset % 8)
2429 				return -EINVAL;
2430 			spec->offset += offset / 8;
2431 
2432 			m = btf_members(t) + access_idx;
2433 			if (m->name_off) {
2434 				name = btf__name_by_offset(btf, m->name_off);
2435 				if (str_is_empty(name))
2436 					return -EINVAL;
2437 
2438 				spec->spec[spec->len].type_id = id;
2439 				spec->spec[spec->len].idx = access_idx;
2440 				spec->spec[spec->len].name = name;
2441 				spec->len++;
2442 			}
2443 
2444 			id = m->type;
2445 		} else if (btf_is_array(t)) {
2446 			const struct btf_array *a = btf_array(t);
2447 
2448 			t = skip_mods_and_typedefs(btf, a->type, &id);
2449 			if (!t || access_idx >= a->nelems)
2450 				return -EINVAL;
2451 
2452 			spec->spec[spec->len].type_id = id;
2453 			spec->spec[spec->len].idx = access_idx;
2454 			spec->len++;
2455 
2456 			sz = btf__resolve_size(btf, id);
2457 			if (sz < 0)
2458 				return sz;
2459 			spec->offset += access_idx * sz;
2460 		} else {
2461 			pr_warning("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n",
2462 				   type_id, spec_str, i, id, btf_kind(t));
2463 			return -EINVAL;
2464 		}
2465 	}
2466 
2467 	return 0;
2468 }
2469 
bpf_core_is_flavor_sep(const char * s)2470 static bool bpf_core_is_flavor_sep(const char *s)
2471 {
2472 	/* check X___Y name pattern, where X and Y are not underscores */
2473 	return s[0] != '_' &&				      /* X */
2474 	       s[1] == '_' && s[2] == '_' && s[3] == '_' &&   /* ___ */
2475 	       s[4] != '_';				      /* Y */
2476 }
2477 
2478 /* Given 'some_struct_name___with_flavor' return the length of a name prefix
2479  * before last triple underscore. Struct name part after last triple
2480  * underscore is ignored by BPF CO-RE relocation during relocation matching.
2481  */
bpf_core_essential_name_len(const char * name)2482 static size_t bpf_core_essential_name_len(const char *name)
2483 {
2484 	size_t n = strlen(name);
2485 	int i;
2486 
2487 	for (i = n - 5; i >= 0; i--) {
2488 		if (bpf_core_is_flavor_sep(name + i))
2489 			return i + 1;
2490 	}
2491 	return n;
2492 }
2493 
2494 /* dynamically sized list of type IDs */
2495 struct ids_vec {
2496 	__u32 *data;
2497 	int len;
2498 };
2499 
bpf_core_free_cands(struct ids_vec * cand_ids)2500 static void bpf_core_free_cands(struct ids_vec *cand_ids)
2501 {
2502 	free(cand_ids->data);
2503 	free(cand_ids);
2504 }
2505 
bpf_core_find_cands(const struct btf * local_btf,__u32 local_type_id,const struct btf * targ_btf)2506 static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
2507 					   __u32 local_type_id,
2508 					   const struct btf *targ_btf)
2509 {
2510 	size_t local_essent_len, targ_essent_len;
2511 	const char *local_name, *targ_name;
2512 	const struct btf_type *t;
2513 	struct ids_vec *cand_ids;
2514 	__u32 *new_ids;
2515 	int i, err, n;
2516 
2517 	t = btf__type_by_id(local_btf, local_type_id);
2518 	if (!t)
2519 		return ERR_PTR(-EINVAL);
2520 
2521 	local_name = btf__name_by_offset(local_btf, t->name_off);
2522 	if (str_is_empty(local_name))
2523 		return ERR_PTR(-EINVAL);
2524 	local_essent_len = bpf_core_essential_name_len(local_name);
2525 
2526 	cand_ids = calloc(1, sizeof(*cand_ids));
2527 	if (!cand_ids)
2528 		return ERR_PTR(-ENOMEM);
2529 
2530 	n = btf__get_nr_types(targ_btf);
2531 	for (i = 1; i <= n; i++) {
2532 		t = btf__type_by_id(targ_btf, i);
2533 		targ_name = btf__name_by_offset(targ_btf, t->name_off);
2534 		if (str_is_empty(targ_name))
2535 			continue;
2536 
2537 		targ_essent_len = bpf_core_essential_name_len(targ_name);
2538 		if (targ_essent_len != local_essent_len)
2539 			continue;
2540 
2541 		if (strncmp(local_name, targ_name, local_essent_len) == 0) {
2542 			pr_debug("[%d] %s: found candidate [%d] %s\n",
2543 				 local_type_id, local_name, i, targ_name);
2544 			new_ids = realloc(cand_ids->data, cand_ids->len + 1);
2545 			if (!new_ids) {
2546 				err = -ENOMEM;
2547 				goto err_out;
2548 			}
2549 			cand_ids->data = new_ids;
2550 			cand_ids->data[cand_ids->len++] = i;
2551 		}
2552 	}
2553 	return cand_ids;
2554 err_out:
2555 	bpf_core_free_cands(cand_ids);
2556 	return ERR_PTR(err);
2557 }
2558 
2559 /* Check two types for compatibility, skipping const/volatile/restrict and
2560  * typedefs, to ensure we are relocating offset to the compatible entities:
2561  *   - any two STRUCTs/UNIONs are compatible and can be mixed;
2562  *   - any two FWDs are compatible;
2563  *   - any two PTRs are always compatible;
2564  *   - for ENUMs, check sizes, names are ignored;
2565  *   - for INT, size and bitness should match, signedness is ignored;
2566  *   - for ARRAY, dimensionality is ignored, element types are checked for
2567  *     compatibility recursively;
2568  *   - everything else shouldn't be ever a target of relocation.
2569  * These rules are not set in stone and probably will be adjusted as we get
2570  * more experience with using BPF CO-RE relocations.
2571  */
bpf_core_fields_are_compat(const struct btf * local_btf,__u32 local_id,const struct btf * targ_btf,__u32 targ_id)2572 static int bpf_core_fields_are_compat(const struct btf *local_btf,
2573 				      __u32 local_id,
2574 				      const struct btf *targ_btf,
2575 				      __u32 targ_id)
2576 {
2577 	const struct btf_type *local_type, *targ_type;
2578 
2579 recur:
2580 	local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
2581 	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
2582 	if (!local_type || !targ_type)
2583 		return -EINVAL;
2584 
2585 	if (btf_is_composite(local_type) && btf_is_composite(targ_type))
2586 		return 1;
2587 	if (btf_kind(local_type) != btf_kind(targ_type))
2588 		return 0;
2589 
2590 	switch (btf_kind(local_type)) {
2591 	case BTF_KIND_FWD:
2592 	case BTF_KIND_PTR:
2593 		return 1;
2594 	case BTF_KIND_ENUM:
2595 		return local_type->size == targ_type->size;
2596 	case BTF_KIND_INT:
2597 		return btf_int_offset(local_type) == 0 &&
2598 		       btf_int_offset(targ_type) == 0 &&
2599 		       local_type->size == targ_type->size &&
2600 		       btf_int_bits(local_type) == btf_int_bits(targ_type);
2601 	case BTF_KIND_ARRAY:
2602 		local_id = btf_array(local_type)->type;
2603 		targ_id = btf_array(targ_type)->type;
2604 		goto recur;
2605 	default:
2606 		pr_warning("unexpected kind %d relocated, local [%d], target [%d]\n",
2607 			   btf_kind(local_type), local_id, targ_id);
2608 		return 0;
2609 	}
2610 }
2611 
2612 /*
2613  * Given single high-level named field accessor in local type, find
2614  * corresponding high-level accessor for a target type. Along the way,
2615  * maintain low-level spec for target as well. Also keep updating target
2616  * offset.
2617  *
2618  * Searching is performed through recursive exhaustive enumeration of all
2619  * fields of a struct/union. If there are any anonymous (embedded)
2620  * structs/unions, they are recursively searched as well. If field with
2621  * desired name is found, check compatibility between local and target types,
2622  * before returning result.
2623  *
2624  * 1 is returned, if field is found.
2625  * 0 is returned if no compatible field is found.
2626  * <0 is returned on error.
2627  */
bpf_core_match_member(const struct btf * local_btf,const struct bpf_core_accessor * local_acc,const struct btf * targ_btf,__u32 targ_id,struct bpf_core_spec * spec,__u32 * next_targ_id)2628 static int bpf_core_match_member(const struct btf *local_btf,
2629 				 const struct bpf_core_accessor *local_acc,
2630 				 const struct btf *targ_btf,
2631 				 __u32 targ_id,
2632 				 struct bpf_core_spec *spec,
2633 				 __u32 *next_targ_id)
2634 {
2635 	const struct btf_type *local_type, *targ_type;
2636 	const struct btf_member *local_member, *m;
2637 	const char *local_name, *targ_name;
2638 	__u32 local_id;
2639 	int i, n, found;
2640 
2641 	targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
2642 	if (!targ_type)
2643 		return -EINVAL;
2644 	if (!btf_is_composite(targ_type))
2645 		return 0;
2646 
2647 	local_id = local_acc->type_id;
2648 	local_type = btf__type_by_id(local_btf, local_id);
2649 	local_member = btf_members(local_type) + local_acc->idx;
2650 	local_name = btf__name_by_offset(local_btf, local_member->name_off);
2651 
2652 	n = btf_vlen(targ_type);
2653 	m = btf_members(targ_type);
2654 	for (i = 0; i < n; i++, m++) {
2655 		__u32 offset;
2656 
2657 		/* bitfield relocations not supported */
2658 		if (btf_member_bitfield_size(targ_type, i))
2659 			continue;
2660 		offset = btf_member_bit_offset(targ_type, i);
2661 		if (offset % 8)
2662 			continue;
2663 
2664 		/* too deep struct/union/array nesting */
2665 		if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
2666 			return -E2BIG;
2667 
2668 		/* speculate this member will be the good one */
2669 		spec->offset += offset / 8;
2670 		spec->raw_spec[spec->raw_len++] = i;
2671 
2672 		targ_name = btf__name_by_offset(targ_btf, m->name_off);
2673 		if (str_is_empty(targ_name)) {
2674 			/* embedded struct/union, we need to go deeper */
2675 			found = bpf_core_match_member(local_btf, local_acc,
2676 						      targ_btf, m->type,
2677 						      spec, next_targ_id);
2678 			if (found) /* either found or error */
2679 				return found;
2680 		} else if (strcmp(local_name, targ_name) == 0) {
2681 			/* matching named field */
2682 			struct bpf_core_accessor *targ_acc;
2683 
2684 			targ_acc = &spec->spec[spec->len++];
2685 			targ_acc->type_id = targ_id;
2686 			targ_acc->idx = i;
2687 			targ_acc->name = targ_name;
2688 
2689 			*next_targ_id = m->type;
2690 			found = bpf_core_fields_are_compat(local_btf,
2691 							   local_member->type,
2692 							   targ_btf, m->type);
2693 			if (!found)
2694 				spec->len--; /* pop accessor */
2695 			return found;
2696 		}
2697 		/* member turned out not to be what we looked for */
2698 		spec->offset -= offset / 8;
2699 		spec->raw_len--;
2700 	}
2701 
2702 	return 0;
2703 }
2704 
2705 /*
2706  * Try to match local spec to a target type and, if successful, produce full
2707  * target spec (high-level, low-level + offset).
2708  */
bpf_core_spec_match(struct bpf_core_spec * local_spec,const struct btf * targ_btf,__u32 targ_id,struct bpf_core_spec * targ_spec)2709 static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
2710 			       const struct btf *targ_btf, __u32 targ_id,
2711 			       struct bpf_core_spec *targ_spec)
2712 {
2713 	const struct btf_type *targ_type;
2714 	const struct bpf_core_accessor *local_acc;
2715 	struct bpf_core_accessor *targ_acc;
2716 	int i, sz, matched;
2717 
2718 	memset(targ_spec, 0, sizeof(*targ_spec));
2719 	targ_spec->btf = targ_btf;
2720 
2721 	local_acc = &local_spec->spec[0];
2722 	targ_acc = &targ_spec->spec[0];
2723 
2724 	for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
2725 		targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
2726 						   &targ_id);
2727 		if (!targ_type)
2728 			return -EINVAL;
2729 
2730 		if (local_acc->name) {
2731 			matched = bpf_core_match_member(local_spec->btf,
2732 							local_acc,
2733 							targ_btf, targ_id,
2734 							targ_spec, &targ_id);
2735 			if (matched <= 0)
2736 				return matched;
2737 		} else {
2738 			/* for i=0, targ_id is already treated as array element
2739 			 * type (because it's the original struct), for others
2740 			 * we should find array element type first
2741 			 */
2742 			if (i > 0) {
2743 				const struct btf_array *a;
2744 
2745 				if (!btf_is_array(targ_type))
2746 					return 0;
2747 
2748 				a = btf_array(targ_type);
2749 				if (local_acc->idx >= a->nelems)
2750 					return 0;
2751 				if (!skip_mods_and_typedefs(targ_btf, a->type,
2752 							    &targ_id))
2753 					return -EINVAL;
2754 			}
2755 
2756 			/* too deep struct/union/array nesting */
2757 			if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
2758 				return -E2BIG;
2759 
2760 			targ_acc->type_id = targ_id;
2761 			targ_acc->idx = local_acc->idx;
2762 			targ_acc->name = NULL;
2763 			targ_spec->len++;
2764 			targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
2765 			targ_spec->raw_len++;
2766 
2767 			sz = btf__resolve_size(targ_btf, targ_id);
2768 			if (sz < 0)
2769 				return sz;
2770 			targ_spec->offset += local_acc->idx * sz;
2771 		}
2772 	}
2773 
2774 	return 1;
2775 }
2776 
2777 /*
2778  * Patch relocatable BPF instruction.
2779  * Expected insn->imm value is provided for validation, as well as the new
2780  * relocated value.
2781  *
2782  * Currently three kinds of BPF instructions are supported:
2783  * 1. rX = <imm> (assignment with immediate operand);
2784  * 2. rX += <imm> (arithmetic operations with immediate operand);
2785  * 3. *(rX) = <imm> (indirect memory assignment with immediate operand).
2786  *
2787  * If actual insn->imm value is wrong, bail out.
2788  */
bpf_core_reloc_insn(struct bpf_program * prog,int insn_off,__u32 orig_off,__u32 new_off)2789 static int bpf_core_reloc_insn(struct bpf_program *prog, int insn_off,
2790 			       __u32 orig_off, __u32 new_off)
2791 {
2792 	struct bpf_insn *insn;
2793 	int insn_idx;
2794 	__u8 class;
2795 
2796 	if (insn_off % sizeof(struct bpf_insn))
2797 		return -EINVAL;
2798 	insn_idx = insn_off / sizeof(struct bpf_insn);
2799 
2800 	insn = &prog->insns[insn_idx];
2801 	class = BPF_CLASS(insn->code);
2802 
2803 	if (class == BPF_ALU || class == BPF_ALU64) {
2804 		if (BPF_SRC(insn->code) != BPF_K)
2805 			return -EINVAL;
2806 		if (insn->imm != orig_off)
2807 			return -EINVAL;
2808 		insn->imm = new_off;
2809 		pr_debug("prog '%s': patched insn #%d (ALU/ALU64) imm %d -> %d\n",
2810 			 bpf_program__title(prog, false),
2811 			 insn_idx, orig_off, new_off);
2812 	} else {
2813 		pr_warning("prog '%s': trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
2814 			   bpf_program__title(prog, false),
2815 			   insn_idx, insn->code, insn->src_reg, insn->dst_reg,
2816 			   insn->off, insn->imm);
2817 		return -EINVAL;
2818 	}
2819 	return 0;
2820 }
2821 
btf_load_raw(const char * path)2822 static struct btf *btf_load_raw(const char *path)
2823 {
2824 	struct btf *btf;
2825 	size_t read_cnt;
2826 	struct stat st;
2827 	void *data;
2828 	FILE *f;
2829 
2830 	if (stat(path, &st))
2831 		return ERR_PTR(-errno);
2832 
2833 	data = malloc(st.st_size);
2834 	if (!data)
2835 		return ERR_PTR(-ENOMEM);
2836 
2837 	f = fopen(path, "rb");
2838 	if (!f) {
2839 		btf = ERR_PTR(-errno);
2840 		goto cleanup;
2841 	}
2842 
2843 	read_cnt = fread(data, 1, st.st_size, f);
2844 	fclose(f);
2845 	if (read_cnt < st.st_size) {
2846 		btf = ERR_PTR(-EBADF);
2847 		goto cleanup;
2848 	}
2849 
2850 	btf = btf__new(data, read_cnt);
2851 
2852 cleanup:
2853 	free(data);
2854 	return btf;
2855 }
2856 
2857 /*
2858  * Probe few well-known locations for vmlinux kernel image and try to load BTF
2859  * data out of it to use for target BTF.
2860  */
bpf_core_find_kernel_btf(void)2861 static struct btf *bpf_core_find_kernel_btf(void)
2862 {
2863 	struct {
2864 		const char *path_fmt;
2865 		bool raw_btf;
2866 	} locations[] = {
2867 		/* try canonical vmlinux BTF through sysfs first */
2868 		{ "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
2869 		/* fall back to trying to find vmlinux ELF on disk otherwise */
2870 		{ "/boot/vmlinux-%1$s" },
2871 		{ "/lib/modules/%1$s/vmlinux-%1$s" },
2872 		{ "/lib/modules/%1$s/build/vmlinux" },
2873 		{ "/usr/lib/modules/%1$s/kernel/vmlinux" },
2874 		{ "/usr/lib/debug/boot/vmlinux-%1$s" },
2875 		{ "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
2876 		{ "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
2877 	};
2878 	char path[PATH_MAX + 1];
2879 	struct utsname buf;
2880 	struct btf *btf;
2881 	int i;
2882 
2883 	uname(&buf);
2884 
2885 	for (i = 0; i < ARRAY_SIZE(locations); i++) {
2886 		snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
2887 
2888 		if (access(path, R_OK))
2889 			continue;
2890 
2891 		if (locations[i].raw_btf)
2892 			btf = btf_load_raw(path);
2893 		else
2894 			btf = btf__parse_elf(path, NULL);
2895 
2896 		pr_debug("loading kernel BTF '%s': %ld\n",
2897 			 path, IS_ERR(btf) ? PTR_ERR(btf) : 0);
2898 		if (IS_ERR(btf))
2899 			continue;
2900 
2901 		return btf;
2902 	}
2903 
2904 	pr_warning("failed to find valid kernel BTF\n");
2905 	return ERR_PTR(-ESRCH);
2906 }
2907 
2908 /* Output spec definition in the format:
2909  * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
2910  * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
2911  */
bpf_core_dump_spec(int level,const struct bpf_core_spec * spec)2912 static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
2913 {
2914 	const struct btf_type *t;
2915 	const char *s;
2916 	__u32 type_id;
2917 	int i;
2918 
2919 	type_id = spec->spec[0].type_id;
2920 	t = btf__type_by_id(spec->btf, type_id);
2921 	s = btf__name_by_offset(spec->btf, t->name_off);
2922 	libbpf_print(level, "[%u] %s + ", type_id, s);
2923 
2924 	for (i = 0; i < spec->raw_len; i++)
2925 		libbpf_print(level, "%d%s", spec->raw_spec[i],
2926 			     i == spec->raw_len - 1 ? " => " : ":");
2927 
2928 	libbpf_print(level, "%u @ &x", spec->offset);
2929 
2930 	for (i = 0; i < spec->len; i++) {
2931 		if (spec->spec[i].name)
2932 			libbpf_print(level, ".%s", spec->spec[i].name);
2933 		else
2934 			libbpf_print(level, "[%u]", spec->spec[i].idx);
2935 	}
2936 
2937 }
2938 
bpf_core_hash_fn(const void * key,void * ctx)2939 static size_t bpf_core_hash_fn(const void *key, void *ctx)
2940 {
2941 	return (size_t)key;
2942 }
2943 
bpf_core_equal_fn(const void * k1,const void * k2,void * ctx)2944 static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
2945 {
2946 	return k1 == k2;
2947 }
2948 
u32_as_hash_key(__u32 x)2949 static void *u32_as_hash_key(__u32 x)
2950 {
2951 	return (void *)(uintptr_t)x;
2952 }
2953 
2954 /*
2955  * CO-RE relocate single instruction.
2956  *
2957  * The outline and important points of the algorithm:
2958  * 1. For given local type, find corresponding candidate target types.
2959  *    Candidate type is a type with the same "essential" name, ignoring
2960  *    everything after last triple underscore (___). E.g., `sample`,
2961  *    `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
2962  *    for each other. Names with triple underscore are referred to as
2963  *    "flavors" and are useful, among other things, to allow to
2964  *    specify/support incompatible variations of the same kernel struct, which
2965  *    might differ between different kernel versions and/or build
2966  *    configurations.
2967  *
2968  *    N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
2969  *    converter, when deduplicated BTF of a kernel still contains more than
2970  *    one different types with the same name. In that case, ___2, ___3, etc
2971  *    are appended starting from second name conflict. But start flavors are
2972  *    also useful to be defined "locally", in BPF program, to extract same
2973  *    data from incompatible changes between different kernel
2974  *    versions/configurations. For instance, to handle field renames between
2975  *    kernel versions, one can use two flavors of the struct name with the
2976  *    same common name and use conditional relocations to extract that field,
2977  *    depending on target kernel version.
2978  * 2. For each candidate type, try to match local specification to this
2979  *    candidate target type. Matching involves finding corresponding
2980  *    high-level spec accessors, meaning that all named fields should match,
2981  *    as well as all array accesses should be within the actual bounds. Also,
2982  *    types should be compatible (see bpf_core_fields_are_compat for details).
2983  * 3. It is supported and expected that there might be multiple flavors
2984  *    matching the spec. As long as all the specs resolve to the same set of
2985  *    offsets across all candidates, there is not error. If there is any
2986  *    ambiguity, CO-RE relocation will fail. This is necessary to accomodate
2987  *    imprefection of BTF deduplication, which can cause slight duplication of
2988  *    the same BTF type, if some directly or indirectly referenced (by
2989  *    pointer) type gets resolved to different actual types in different
2990  *    object files. If such situation occurs, deduplicated BTF will end up
2991  *    with two (or more) structurally identical types, which differ only in
2992  *    types they refer to through pointer. This should be OK in most cases and
2993  *    is not an error.
2994  * 4. Candidate types search is performed by linearly scanning through all
2995  *    types in target BTF. It is anticipated that this is overall more
2996  *    efficient memory-wise and not significantly worse (if not better)
2997  *    CPU-wise compared to prebuilding a map from all local type names to
2998  *    a list of candidate type names. It's also sped up by caching resolved
2999  *    list of matching candidates per each local "root" type ID, that has at
3000  *    least one bpf_offset_reloc associated with it. This list is shared
3001  *    between multiple relocations for the same type ID and is updated as some
3002  *    of the candidates are pruned due to structural incompatibility.
3003  */
bpf_core_reloc_offset(struct bpf_program * prog,const struct bpf_offset_reloc * relo,int relo_idx,const struct btf * local_btf,const struct btf * targ_btf,struct hashmap * cand_cache)3004 static int bpf_core_reloc_offset(struct bpf_program *prog,
3005 				 const struct bpf_offset_reloc *relo,
3006 				 int relo_idx,
3007 				 const struct btf *local_btf,
3008 				 const struct btf *targ_btf,
3009 				 struct hashmap *cand_cache)
3010 {
3011 	const char *prog_name = bpf_program__title(prog, false);
3012 	struct bpf_core_spec local_spec, cand_spec, targ_spec;
3013 	const void *type_key = u32_as_hash_key(relo->type_id);
3014 	const struct btf_type *local_type, *cand_type;
3015 	const char *local_name, *cand_name;
3016 	struct ids_vec *cand_ids;
3017 	__u32 local_id, cand_id;
3018 	const char *spec_str;
3019 	int i, j, err;
3020 
3021 	local_id = relo->type_id;
3022 	local_type = btf__type_by_id(local_btf, local_id);
3023 	if (!local_type)
3024 		return -EINVAL;
3025 
3026 	local_name = btf__name_by_offset(local_btf, local_type->name_off);
3027 	if (str_is_empty(local_name))
3028 		return -EINVAL;
3029 
3030 	spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
3031 	if (str_is_empty(spec_str))
3032 		return -EINVAL;
3033 
3034 	err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec);
3035 	if (err) {
3036 		pr_warning("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n",
3037 			   prog_name, relo_idx, local_id, local_name, spec_str,
3038 			   err);
3039 		return -EINVAL;
3040 	}
3041 
3042 	pr_debug("prog '%s': relo #%d: spec is ", prog_name, relo_idx);
3043 	bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
3044 	libbpf_print(LIBBPF_DEBUG, "\n");
3045 
3046 	if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
3047 		cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
3048 		if (IS_ERR(cand_ids)) {
3049 			pr_warning("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld",
3050 				   prog_name, relo_idx, local_id, local_name,
3051 				   PTR_ERR(cand_ids));
3052 			return PTR_ERR(cand_ids);
3053 		}
3054 		err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
3055 		if (err) {
3056 			bpf_core_free_cands(cand_ids);
3057 			return err;
3058 		}
3059 	}
3060 
3061 	for (i = 0, j = 0; i < cand_ids->len; i++) {
3062 		cand_id = cand_ids->data[i];
3063 		cand_type = btf__type_by_id(targ_btf, cand_id);
3064 		cand_name = btf__name_by_offset(targ_btf, cand_type->name_off);
3065 
3066 		err = bpf_core_spec_match(&local_spec, targ_btf,
3067 					  cand_id, &cand_spec);
3068 		pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ",
3069 			 prog_name, relo_idx, i, cand_name);
3070 		bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
3071 		libbpf_print(LIBBPF_DEBUG, ": %d\n", err);
3072 		if (err < 0) {
3073 			pr_warning("prog '%s': relo #%d: matching error: %d\n",
3074 				   prog_name, relo_idx, err);
3075 			return err;
3076 		}
3077 		if (err == 0)
3078 			continue;
3079 
3080 		if (j == 0) {
3081 			targ_spec = cand_spec;
3082 		} else if (cand_spec.offset != targ_spec.offset) {
3083 			/* if there are many candidates, they should all
3084 			 * resolve to the same offset
3085 			 */
3086 			pr_warning("prog '%s': relo #%d: offset ambiguity: %u != %u\n",
3087 				   prog_name, relo_idx, cand_spec.offset,
3088 				   targ_spec.offset);
3089 			return -EINVAL;
3090 		}
3091 
3092 		cand_ids->data[j++] = cand_spec.spec[0].type_id;
3093 	}
3094 
3095 	cand_ids->len = j;
3096 	if (cand_ids->len == 0) {
3097 		pr_warning("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
3098 			   prog_name, relo_idx, local_id, local_name, spec_str);
3099 		return -ESRCH;
3100 	}
3101 
3102 	err = bpf_core_reloc_insn(prog, relo->insn_off,
3103 				  local_spec.offset, targ_spec.offset);
3104 	if (err) {
3105 		pr_warning("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
3106 			   prog_name, relo_idx, relo->insn_off, err);
3107 		return -EINVAL;
3108 	}
3109 
3110 	return 0;
3111 }
3112 
3113 static int
bpf_core_reloc_offsets(struct bpf_object * obj,const char * targ_btf_path)3114 bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
3115 {
3116 	const struct btf_ext_info_sec *sec;
3117 	const struct bpf_offset_reloc *rec;
3118 	const struct btf_ext_info *seg;
3119 	struct hashmap_entry *entry;
3120 	struct hashmap *cand_cache = NULL;
3121 	struct bpf_program *prog;
3122 	struct btf *targ_btf;
3123 	const char *sec_name;
3124 	int i, err = 0;
3125 
3126 	if (targ_btf_path)
3127 		targ_btf = btf__parse_elf(targ_btf_path, NULL);
3128 	else
3129 		targ_btf = bpf_core_find_kernel_btf();
3130 	if (IS_ERR(targ_btf)) {
3131 		pr_warning("failed to get target BTF: %ld\n",
3132 			   PTR_ERR(targ_btf));
3133 		return PTR_ERR(targ_btf);
3134 	}
3135 
3136 	cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
3137 	if (IS_ERR(cand_cache)) {
3138 		err = PTR_ERR(cand_cache);
3139 		goto out;
3140 	}
3141 
3142 	seg = &obj->btf_ext->offset_reloc_info;
3143 	for_each_btf_ext_sec(seg, sec) {
3144 		sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
3145 		if (str_is_empty(sec_name)) {
3146 			err = -EINVAL;
3147 			goto out;
3148 		}
3149 		prog = bpf_object__find_program_by_title(obj, sec_name);
3150 		if (!prog) {
3151 			pr_warning("failed to find program '%s' for CO-RE offset relocation\n",
3152 				   sec_name);
3153 			err = -EINVAL;
3154 			goto out;
3155 		}
3156 
3157 		pr_debug("prog '%s': performing %d CO-RE offset relocs\n",
3158 			 sec_name, sec->num_info);
3159 
3160 		for_each_btf_ext_rec(seg, sec, i, rec) {
3161 			err = bpf_core_reloc_offset(prog, rec, i, obj->btf,
3162 						    targ_btf, cand_cache);
3163 			if (err) {
3164 				pr_warning("prog '%s': relo #%d: failed to relocate: %d\n",
3165 					   sec_name, i, err);
3166 				goto out;
3167 			}
3168 		}
3169 	}
3170 
3171 out:
3172 	btf__free(targ_btf);
3173 	if (!IS_ERR_OR_NULL(cand_cache)) {
3174 		hashmap__for_each_entry(cand_cache, entry, i) {
3175 			bpf_core_free_cands(entry->value);
3176 		}
3177 		hashmap__free(cand_cache);
3178 	}
3179 	return err;
3180 }
3181 
3182 static int
bpf_object__relocate_core(struct bpf_object * obj,const char * targ_btf_path)3183 bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
3184 {
3185 	int err = 0;
3186 
3187 	if (obj->btf_ext->offset_reloc_info.len)
3188 		err = bpf_core_reloc_offsets(obj, targ_btf_path);
3189 
3190 	return err;
3191 }
3192 
3193 static int
bpf_program__reloc_text(struct bpf_program * prog,struct bpf_object * obj,struct reloc_desc * relo)3194 bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
3195 			struct reloc_desc *relo)
3196 {
3197 	struct bpf_insn *insn, *new_insn;
3198 	struct bpf_program *text;
3199 	size_t new_cnt;
3200 	int err;
3201 
3202 	if (relo->type != RELO_CALL)
3203 		return -LIBBPF_ERRNO__RELOC;
3204 
3205 	if (prog->idx == obj->efile.text_shndx) {
3206 		pr_warning("relo in .text insn %d into off %d\n",
3207 			   relo->insn_idx, relo->text_off);
3208 		return -LIBBPF_ERRNO__RELOC;
3209 	}
3210 
3211 	if (prog->main_prog_cnt == 0) {
3212 		text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
3213 		if (!text) {
3214 			pr_warning("no .text section found yet relo into text exist\n");
3215 			return -LIBBPF_ERRNO__RELOC;
3216 		}
3217 		new_cnt = prog->insns_cnt + text->insns_cnt;
3218 		new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
3219 		if (!new_insn) {
3220 			pr_warning("oom in prog realloc\n");
3221 			return -ENOMEM;
3222 		}
3223 		prog->insns = new_insn;
3224 
3225 		if (obj->btf_ext) {
3226 			err = bpf_program_reloc_btf_ext(prog, obj,
3227 							text->section_name,
3228 							prog->insns_cnt);
3229 			if (err)
3230 				return err;
3231 		}
3232 
3233 		memcpy(new_insn + prog->insns_cnt, text->insns,
3234 		       text->insns_cnt * sizeof(*insn));
3235 		prog->main_prog_cnt = prog->insns_cnt;
3236 		prog->insns_cnt = new_cnt;
3237 		pr_debug("added %zd insn from %s to prog %s\n",
3238 			 text->insns_cnt, text->section_name,
3239 			 prog->section_name);
3240 	}
3241 	insn = &prog->insns[relo->insn_idx];
3242 	insn->imm += prog->main_prog_cnt - relo->insn_idx;
3243 	return 0;
3244 }
3245 
3246 static int
bpf_program__relocate(struct bpf_program * prog,struct bpf_object * obj)3247 bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
3248 {
3249 	int i, err;
3250 
3251 	if (!prog)
3252 		return 0;
3253 
3254 	if (obj->btf_ext) {
3255 		err = bpf_program_reloc_btf_ext(prog, obj,
3256 						prog->section_name, 0);
3257 		if (err)
3258 			return err;
3259 	}
3260 
3261 	if (!prog->reloc_desc)
3262 		return 0;
3263 
3264 	for (i = 0; i < prog->nr_reloc; i++) {
3265 		if (prog->reloc_desc[i].type == RELO_LD64 ||
3266 		    prog->reloc_desc[i].type == RELO_DATA) {
3267 			bool relo_data = prog->reloc_desc[i].type == RELO_DATA;
3268 			struct bpf_insn *insns = prog->insns;
3269 			int insn_idx, map_idx;
3270 
3271 			insn_idx = prog->reloc_desc[i].insn_idx;
3272 			map_idx = prog->reloc_desc[i].map_idx;
3273 
3274 			if (insn_idx + 1 >= (int)prog->insns_cnt) {
3275 				pr_warning("relocation out of range: '%s'\n",
3276 					   prog->section_name);
3277 				return -LIBBPF_ERRNO__RELOC;
3278 			}
3279 
3280 			if (!relo_data) {
3281 				insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
3282 			} else {
3283 				insns[insn_idx].src_reg = BPF_PSEUDO_MAP_VALUE;
3284 				insns[insn_idx + 1].imm = insns[insn_idx].imm;
3285 			}
3286 			insns[insn_idx].imm = obj->maps[map_idx].fd;
3287 		} else if (prog->reloc_desc[i].type == RELO_CALL) {
3288 			err = bpf_program__reloc_text(prog, obj,
3289 						      &prog->reloc_desc[i]);
3290 			if (err)
3291 				return err;
3292 		}
3293 	}
3294 
3295 	zfree(&prog->reloc_desc);
3296 	prog->nr_reloc = 0;
3297 	return 0;
3298 }
3299 
3300 static int
bpf_object__relocate(struct bpf_object * obj,const char * targ_btf_path)3301 bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
3302 {
3303 	struct bpf_program *prog;
3304 	size_t i;
3305 	int err;
3306 
3307 	if (obj->btf_ext) {
3308 		err = bpf_object__relocate_core(obj, targ_btf_path);
3309 		if (err) {
3310 			pr_warning("failed to perform CO-RE relocations: %d\n",
3311 				   err);
3312 			return err;
3313 		}
3314 	}
3315 	for (i = 0; i < obj->nr_programs; i++) {
3316 		prog = &obj->programs[i];
3317 
3318 		err = bpf_program__relocate(prog, obj);
3319 		if (err) {
3320 			pr_warning("failed to relocate '%s'\n",
3321 				   prog->section_name);
3322 			return err;
3323 		}
3324 	}
3325 	return 0;
3326 }
3327 
bpf_object__collect_reloc(struct bpf_object * obj)3328 static int bpf_object__collect_reloc(struct bpf_object *obj)
3329 {
3330 	int i, err;
3331 
3332 	if (!obj_elf_valid(obj)) {
3333 		pr_warning("Internal error: elf object is closed\n");
3334 		return -LIBBPF_ERRNO__INTERNAL;
3335 	}
3336 
3337 	for (i = 0; i < obj->efile.nr_reloc; i++) {
3338 		GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
3339 		Elf_Data *data = obj->efile.reloc[i].data;
3340 		int idx = shdr->sh_info;
3341 		struct bpf_program *prog;
3342 
3343 		if (shdr->sh_type != SHT_REL) {
3344 			pr_warning("internal error at %d\n", __LINE__);
3345 			return -LIBBPF_ERRNO__INTERNAL;
3346 		}
3347 
3348 		prog = bpf_object__find_prog_by_idx(obj, idx);
3349 		if (!prog) {
3350 			pr_warning("relocation failed: no section(%d)\n", idx);
3351 			return -LIBBPF_ERRNO__RELOC;
3352 		}
3353 
3354 		err = bpf_program__collect_reloc(prog, shdr, data, obj);
3355 		if (err)
3356 			return err;
3357 	}
3358 	return 0;
3359 }
3360 
3361 static int
load_program(struct bpf_program * prog,struct bpf_insn * insns,int insns_cnt,char * license,__u32 kern_version,int * pfd)3362 load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
3363 	     char *license, __u32 kern_version, int *pfd)
3364 {
3365 	struct bpf_load_program_attr load_attr;
3366 	char *cp, errmsg[STRERR_BUFSIZE];
3367 	int log_buf_size = BPF_LOG_BUF_SIZE;
3368 	char *log_buf;
3369 	int btf_fd, ret;
3370 
3371 	if (!insns || !insns_cnt)
3372 		return -EINVAL;
3373 
3374 	memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
3375 	load_attr.prog_type = prog->type;
3376 	load_attr.expected_attach_type = prog->expected_attach_type;
3377 	if (prog->caps->name)
3378 		load_attr.name = prog->name;
3379 	load_attr.insns = insns;
3380 	load_attr.insns_cnt = insns_cnt;
3381 	load_attr.license = license;
3382 	load_attr.kern_version = kern_version;
3383 	load_attr.prog_ifindex = prog->prog_ifindex;
3384 	/* if .BTF.ext was loaded, kernel supports associated BTF for prog */
3385 	if (prog->obj->btf_ext)
3386 		btf_fd = bpf_object__btf_fd(prog->obj);
3387 	else
3388 		btf_fd = -1;
3389 	load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
3390 	load_attr.func_info = prog->func_info;
3391 	load_attr.func_info_rec_size = prog->func_info_rec_size;
3392 	load_attr.func_info_cnt = prog->func_info_cnt;
3393 	load_attr.line_info = prog->line_info;
3394 	load_attr.line_info_rec_size = prog->line_info_rec_size;
3395 	load_attr.line_info_cnt = prog->line_info_cnt;
3396 	load_attr.log_level = prog->log_level;
3397 	load_attr.prog_flags = prog->prog_flags;
3398 
3399 retry_load:
3400 	log_buf = malloc(log_buf_size);
3401 	if (!log_buf)
3402 		pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
3403 
3404 	ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
3405 
3406 	if (ret >= 0) {
3407 		if (load_attr.log_level)
3408 			pr_debug("verifier log:\n%s", log_buf);
3409 		*pfd = ret;
3410 		ret = 0;
3411 		goto out;
3412 	}
3413 
3414 	if (errno == ENOSPC) {
3415 		log_buf_size <<= 1;
3416 		free(log_buf);
3417 		goto retry_load;
3418 	}
3419 	ret = -LIBBPF_ERRNO__LOAD;
3420 	cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3421 	pr_warning("load bpf program failed: %s\n", cp);
3422 
3423 	if (log_buf && log_buf[0] != '\0') {
3424 		ret = -LIBBPF_ERRNO__VERIFY;
3425 		pr_warning("-- BEGIN DUMP LOG ---\n");
3426 		pr_warning("\n%s\n", log_buf);
3427 		pr_warning("-- END LOG --\n");
3428 	} else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
3429 		pr_warning("Program too large (%zu insns), at most %d insns\n",
3430 			   load_attr.insns_cnt, BPF_MAXINSNS);
3431 		ret = -LIBBPF_ERRNO__PROG2BIG;
3432 	} else {
3433 		/* Wrong program type? */
3434 		if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
3435 			int fd;
3436 
3437 			load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
3438 			load_attr.expected_attach_type = 0;
3439 			fd = bpf_load_program_xattr(&load_attr, NULL, 0);
3440 			if (fd >= 0) {
3441 				close(fd);
3442 				ret = -LIBBPF_ERRNO__PROGTYPE;
3443 				goto out;
3444 			}
3445 		}
3446 
3447 		if (log_buf)
3448 			ret = -LIBBPF_ERRNO__KVER;
3449 	}
3450 
3451 out:
3452 	free(log_buf);
3453 	return ret;
3454 }
3455 
3456 int
bpf_program__load(struct bpf_program * prog,char * license,__u32 kern_version)3457 bpf_program__load(struct bpf_program *prog,
3458 		  char *license, __u32 kern_version)
3459 {
3460 	int err = 0, fd, i;
3461 
3462 	if (prog->instances.nr < 0 || !prog->instances.fds) {
3463 		if (prog->preprocessor) {
3464 			pr_warning("Internal error: can't load program '%s'\n",
3465 				   prog->section_name);
3466 			return -LIBBPF_ERRNO__INTERNAL;
3467 		}
3468 
3469 		prog->instances.fds = malloc(sizeof(int));
3470 		if (!prog->instances.fds) {
3471 			pr_warning("Not enough memory for BPF fds\n");
3472 			return -ENOMEM;
3473 		}
3474 		prog->instances.nr = 1;
3475 		prog->instances.fds[0] = -1;
3476 	}
3477 
3478 	if (!prog->preprocessor) {
3479 		if (prog->instances.nr != 1) {
3480 			pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
3481 				   prog->section_name, prog->instances.nr);
3482 		}
3483 		err = load_program(prog, prog->insns, prog->insns_cnt,
3484 				   license, kern_version, &fd);
3485 		if (!err)
3486 			prog->instances.fds[0] = fd;
3487 		goto out;
3488 	}
3489 
3490 	for (i = 0; i < prog->instances.nr; i++) {
3491 		struct bpf_prog_prep_result result;
3492 		bpf_program_prep_t preprocessor = prog->preprocessor;
3493 
3494 		memset(&result, 0, sizeof(result));
3495 		err = preprocessor(prog, i, prog->insns,
3496 				   prog->insns_cnt, &result);
3497 		if (err) {
3498 			pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
3499 				   i, prog->section_name);
3500 			goto out;
3501 		}
3502 
3503 		if (!result.new_insn_ptr || !result.new_insn_cnt) {
3504 			pr_debug("Skip loading the %dth instance of program '%s'\n",
3505 				 i, prog->section_name);
3506 			prog->instances.fds[i] = -1;
3507 			if (result.pfd)
3508 				*result.pfd = -1;
3509 			continue;
3510 		}
3511 
3512 		err = load_program(prog, result.new_insn_ptr,
3513 				   result.new_insn_cnt,
3514 				   license, kern_version, &fd);
3515 
3516 		if (err) {
3517 			pr_warning("Loading the %dth instance of program '%s' failed\n",
3518 					i, prog->section_name);
3519 			goto out;
3520 		}
3521 
3522 		if (result.pfd)
3523 			*result.pfd = fd;
3524 		prog->instances.fds[i] = fd;
3525 	}
3526 out:
3527 	if (err)
3528 		pr_warning("failed to load program '%s'\n",
3529 			   prog->section_name);
3530 	zfree(&prog->insns);
3531 	prog->insns_cnt = 0;
3532 	return err;
3533 }
3534 
bpf_program__is_function_storage(const struct bpf_program * prog,const struct bpf_object * obj)3535 static bool bpf_program__is_function_storage(const struct bpf_program *prog,
3536 					     const struct bpf_object *obj)
3537 {
3538 	return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
3539 }
3540 
3541 static int
bpf_object__load_progs(struct bpf_object * obj,int log_level)3542 bpf_object__load_progs(struct bpf_object *obj, int log_level)
3543 {
3544 	size_t i;
3545 	int err;
3546 
3547 	for (i = 0; i < obj->nr_programs; i++) {
3548 		if (bpf_program__is_function_storage(&obj->programs[i], obj))
3549 			continue;
3550 		obj->programs[i].log_level |= log_level;
3551 		err = bpf_program__load(&obj->programs[i],
3552 					obj->license,
3553 					obj->kern_version);
3554 		if (err)
3555 			return err;
3556 	}
3557 	return 0;
3558 }
3559 
bpf_prog_type__needs_kver(enum bpf_prog_type type)3560 static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
3561 {
3562 	switch (type) {
3563 	case BPF_PROG_TYPE_SOCKET_FILTER:
3564 	case BPF_PROG_TYPE_SCHED_CLS:
3565 	case BPF_PROG_TYPE_SCHED_ACT:
3566 	case BPF_PROG_TYPE_XDP:
3567 	case BPF_PROG_TYPE_CGROUP_SKB:
3568 	case BPF_PROG_TYPE_CGROUP_SOCK:
3569 	case BPF_PROG_TYPE_LWT_IN:
3570 	case BPF_PROG_TYPE_LWT_OUT:
3571 	case BPF_PROG_TYPE_LWT_XMIT:
3572 	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
3573 	case BPF_PROG_TYPE_SOCK_OPS:
3574 	case BPF_PROG_TYPE_SK_SKB:
3575 	case BPF_PROG_TYPE_CGROUP_DEVICE:
3576 	case BPF_PROG_TYPE_SK_MSG:
3577 	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
3578 	case BPF_PROG_TYPE_LIRC_MODE2:
3579 	case BPF_PROG_TYPE_SK_REUSEPORT:
3580 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
3581 	case BPF_PROG_TYPE_UNSPEC:
3582 	case BPF_PROG_TYPE_TRACEPOINT:
3583 	case BPF_PROG_TYPE_RAW_TRACEPOINT:
3584 	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
3585 	case BPF_PROG_TYPE_PERF_EVENT:
3586 	case BPF_PROG_TYPE_CGROUP_SYSCTL:
3587 	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
3588 		return false;
3589 	case BPF_PROG_TYPE_KPROBE:
3590 	default:
3591 		return true;
3592 	}
3593 }
3594 
bpf_object__validate(struct bpf_object * obj,bool needs_kver)3595 static int bpf_object__validate(struct bpf_object *obj, bool needs_kver)
3596 {
3597 	if (needs_kver && obj->kern_version == 0) {
3598 		pr_warning("%s doesn't provide kernel version\n",
3599 			   obj->path);
3600 		return -LIBBPF_ERRNO__KVERSION;
3601 	}
3602 	return 0;
3603 }
3604 
3605 static struct bpf_object *
__bpf_object__open(const char * path,void * obj_buf,size_t obj_buf_sz,bool needs_kver,int flags)3606 __bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
3607 		   bool needs_kver, int flags)
3608 {
3609 	struct bpf_object *obj;
3610 	int err;
3611 
3612 	if (elf_version(EV_CURRENT) == EV_NONE) {
3613 		pr_warning("failed to init libelf for %s\n", path);
3614 		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
3615 	}
3616 
3617 	obj = bpf_object__new(path, obj_buf, obj_buf_sz);
3618 	if (IS_ERR(obj))
3619 		return obj;
3620 
3621 	CHECK_ERR(bpf_object__elf_init(obj), err, out);
3622 	CHECK_ERR(bpf_object__check_endianness(obj), err, out);
3623 	CHECK_ERR(bpf_object__probe_caps(obj), err, out);
3624 	CHECK_ERR(bpf_object__elf_collect(obj, flags), err, out);
3625 	CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
3626 	CHECK_ERR(bpf_object__validate(obj, needs_kver), err, out);
3627 
3628 	bpf_object__elf_finish(obj);
3629 	return obj;
3630 out:
3631 	bpf_object__close(obj);
3632 	return ERR_PTR(err);
3633 }
3634 
__bpf_object__open_xattr(struct bpf_object_open_attr * attr,int flags)3635 struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
3636 					    int flags)
3637 {
3638 	/* param validation */
3639 	if (!attr->file)
3640 		return NULL;
3641 
3642 	pr_debug("loading %s\n", attr->file);
3643 
3644 	return __bpf_object__open(attr->file, NULL, 0,
3645 				  bpf_prog_type__needs_kver(attr->prog_type),
3646 				  flags);
3647 }
3648 
bpf_object__open_xattr(struct bpf_object_open_attr * attr)3649 struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
3650 {
3651 	return __bpf_object__open_xattr(attr, 0);
3652 }
3653 
bpf_object__open(const char * path)3654 struct bpf_object *bpf_object__open(const char *path)
3655 {
3656 	struct bpf_object_open_attr attr = {
3657 		.file		= path,
3658 		.prog_type	= BPF_PROG_TYPE_UNSPEC,
3659 	};
3660 
3661 	return bpf_object__open_xattr(&attr);
3662 }
3663 
bpf_object__open_buffer(void * obj_buf,size_t obj_buf_sz,const char * name)3664 struct bpf_object *bpf_object__open_buffer(void *obj_buf,
3665 					   size_t obj_buf_sz,
3666 					   const char *name)
3667 {
3668 	char tmp_name[64];
3669 
3670 	/* param validation */
3671 	if (!obj_buf || obj_buf_sz <= 0)
3672 		return NULL;
3673 
3674 	if (!name) {
3675 		snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
3676 			 (unsigned long)obj_buf,
3677 			 (unsigned long)obj_buf_sz);
3678 		name = tmp_name;
3679 	}
3680 	pr_debug("loading object '%s' from buffer\n", name);
3681 
3682 	return __bpf_object__open(name, obj_buf, obj_buf_sz, true, true);
3683 }
3684 
bpf_object__unload(struct bpf_object * obj)3685 int bpf_object__unload(struct bpf_object *obj)
3686 {
3687 	size_t i;
3688 
3689 	if (!obj)
3690 		return -EINVAL;
3691 
3692 	for (i = 0; i < obj->nr_maps; i++)
3693 		zclose(obj->maps[i].fd);
3694 
3695 	for (i = 0; i < obj->nr_programs; i++)
3696 		bpf_program__unload(&obj->programs[i]);
3697 
3698 	return 0;
3699 }
3700 
bpf_object__load_xattr(struct bpf_object_load_attr * attr)3701 int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
3702 {
3703 	struct bpf_object *obj;
3704 	int err;
3705 
3706 	if (!attr)
3707 		return -EINVAL;
3708 	obj = attr->obj;
3709 	if (!obj)
3710 		return -EINVAL;
3711 
3712 	if (obj->loaded) {
3713 		pr_warning("object should not be loaded twice\n");
3714 		return -EINVAL;
3715 	}
3716 
3717 	obj->loaded = true;
3718 
3719 	CHECK_ERR(bpf_object__create_maps(obj), err, out);
3720 	CHECK_ERR(bpf_object__relocate(obj, attr->target_btf_path), err, out);
3721 	CHECK_ERR(bpf_object__load_progs(obj, attr->log_level), err, out);
3722 
3723 	return 0;
3724 out:
3725 	bpf_object__unload(obj);
3726 	pr_warning("failed to load object '%s'\n", obj->path);
3727 	return err;
3728 }
3729 
bpf_object__load(struct bpf_object * obj)3730 int bpf_object__load(struct bpf_object *obj)
3731 {
3732 	struct bpf_object_load_attr attr = {
3733 		.obj = obj,
3734 	};
3735 
3736 	return bpf_object__load_xattr(&attr);
3737 }
3738 
check_path(const char * path)3739 static int check_path(const char *path)
3740 {
3741 	char *cp, errmsg[STRERR_BUFSIZE];
3742 	struct statfs st_fs;
3743 	char *dname, *dir;
3744 	int err = 0;
3745 
3746 	if (path == NULL)
3747 		return -EINVAL;
3748 
3749 	dname = strdup(path);
3750 	if (dname == NULL)
3751 		return -ENOMEM;
3752 
3753 	dir = dirname(dname);
3754 	if (statfs(dir, &st_fs)) {
3755 		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3756 		pr_warning("failed to statfs %s: %s\n", dir, cp);
3757 		err = -errno;
3758 	}
3759 	free(dname);
3760 
3761 	if (!err && st_fs.f_type != BPF_FS_MAGIC) {
3762 		pr_warning("specified path %s is not on BPF FS\n", path);
3763 		err = -EINVAL;
3764 	}
3765 
3766 	return err;
3767 }
3768 
bpf_program__pin_instance(struct bpf_program * prog,const char * path,int instance)3769 int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
3770 			      int instance)
3771 {
3772 	char *cp, errmsg[STRERR_BUFSIZE];
3773 	int err;
3774 
3775 	err = check_path(path);
3776 	if (err)
3777 		return err;
3778 
3779 	if (prog == NULL) {
3780 		pr_warning("invalid program pointer\n");
3781 		return -EINVAL;
3782 	}
3783 
3784 	if (instance < 0 || instance >= prog->instances.nr) {
3785 		pr_warning("invalid prog instance %d of prog %s (max %d)\n",
3786 			   instance, prog->section_name, prog->instances.nr);
3787 		return -EINVAL;
3788 	}
3789 
3790 	if (bpf_obj_pin(prog->instances.fds[instance], path)) {
3791 		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3792 		pr_warning("failed to pin program: %s\n", cp);
3793 		return -errno;
3794 	}
3795 	pr_debug("pinned program '%s'\n", path);
3796 
3797 	return 0;
3798 }
3799 
bpf_program__unpin_instance(struct bpf_program * prog,const char * path,int instance)3800 int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
3801 				int instance)
3802 {
3803 	int err;
3804 
3805 	err = check_path(path);
3806 	if (err)
3807 		return err;
3808 
3809 	if (prog == NULL) {
3810 		pr_warning("invalid program pointer\n");
3811 		return -EINVAL;
3812 	}
3813 
3814 	if (instance < 0 || instance >= prog->instances.nr) {
3815 		pr_warning("invalid prog instance %d of prog %s (max %d)\n",
3816 			   instance, prog->section_name, prog->instances.nr);
3817 		return -EINVAL;
3818 	}
3819 
3820 	err = unlink(path);
3821 	if (err != 0)
3822 		return -errno;
3823 	pr_debug("unpinned program '%s'\n", path);
3824 
3825 	return 0;
3826 }
3827 
make_dir(const char * path)3828 static int make_dir(const char *path)
3829 {
3830 	char *cp, errmsg[STRERR_BUFSIZE];
3831 	int err = 0;
3832 
3833 	if (mkdir(path, 0700) && errno != EEXIST)
3834 		err = -errno;
3835 
3836 	if (err) {
3837 		cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
3838 		pr_warning("failed to mkdir %s: %s\n", path, cp);
3839 	}
3840 	return err;
3841 }
3842 
bpf_program__pin(struct bpf_program * prog,const char * path)3843 int bpf_program__pin(struct bpf_program *prog, const char *path)
3844 {
3845 	int i, err;
3846 
3847 	err = check_path(path);
3848 	if (err)
3849 		return err;
3850 
3851 	if (prog == NULL) {
3852 		pr_warning("invalid program pointer\n");
3853 		return -EINVAL;
3854 	}
3855 
3856 	if (prog->instances.nr <= 0) {
3857 		pr_warning("no instances of prog %s to pin\n",
3858 			   prog->section_name);
3859 		return -EINVAL;
3860 	}
3861 
3862 	if (prog->instances.nr == 1) {
3863 		/* don't create subdirs when pinning single instance */
3864 		return bpf_program__pin_instance(prog, path, 0);
3865 	}
3866 
3867 	err = make_dir(path);
3868 	if (err)
3869 		return err;
3870 
3871 	for (i = 0; i < prog->instances.nr; i++) {
3872 		char buf[PATH_MAX];
3873 		int len;
3874 
3875 		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
3876 		if (len < 0) {
3877 			err = -EINVAL;
3878 			goto err_unpin;
3879 		} else if (len >= PATH_MAX) {
3880 			err = -ENAMETOOLONG;
3881 			goto err_unpin;
3882 		}
3883 
3884 		err = bpf_program__pin_instance(prog, buf, i);
3885 		if (err)
3886 			goto err_unpin;
3887 	}
3888 
3889 	return 0;
3890 
3891 err_unpin:
3892 	for (i = i - 1; i >= 0; i--) {
3893 		char buf[PATH_MAX];
3894 		int len;
3895 
3896 		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
3897 		if (len < 0)
3898 			continue;
3899 		else if (len >= PATH_MAX)
3900 			continue;
3901 
3902 		bpf_program__unpin_instance(prog, buf, i);
3903 	}
3904 
3905 	rmdir(path);
3906 
3907 	return err;
3908 }
3909 
bpf_program__unpin(struct bpf_program * prog,const char * path)3910 int bpf_program__unpin(struct bpf_program *prog, const char *path)
3911 {
3912 	int i, err;
3913 
3914 	err = check_path(path);
3915 	if (err)
3916 		return err;
3917 
3918 	if (prog == NULL) {
3919 		pr_warning("invalid program pointer\n");
3920 		return -EINVAL;
3921 	}
3922 
3923 	if (prog->instances.nr <= 0) {
3924 		pr_warning("no instances of prog %s to pin\n",
3925 			   prog->section_name);
3926 		return -EINVAL;
3927 	}
3928 
3929 	if (prog->instances.nr == 1) {
3930 		/* don't create subdirs when pinning single instance */
3931 		return bpf_program__unpin_instance(prog, path, 0);
3932 	}
3933 
3934 	for (i = 0; i < prog->instances.nr; i++) {
3935 		char buf[PATH_MAX];
3936 		int len;
3937 
3938 		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
3939 		if (len < 0)
3940 			return -EINVAL;
3941 		else if (len >= PATH_MAX)
3942 			return -ENAMETOOLONG;
3943 
3944 		err = bpf_program__unpin_instance(prog, buf, i);
3945 		if (err)
3946 			return err;
3947 	}
3948 
3949 	err = rmdir(path);
3950 	if (err)
3951 		return -errno;
3952 
3953 	return 0;
3954 }
3955 
bpf_map__pin(struct bpf_map * map,const char * path)3956 int bpf_map__pin(struct bpf_map *map, const char *path)
3957 {
3958 	char *cp, errmsg[STRERR_BUFSIZE];
3959 	int err;
3960 
3961 	err = check_path(path);
3962 	if (err)
3963 		return err;
3964 
3965 	if (map == NULL) {
3966 		pr_warning("invalid map pointer\n");
3967 		return -EINVAL;
3968 	}
3969 
3970 	if (bpf_obj_pin(map->fd, path)) {
3971 		cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
3972 		pr_warning("failed to pin map: %s\n", cp);
3973 		return -errno;
3974 	}
3975 
3976 	pr_debug("pinned map '%s'\n", path);
3977 
3978 	return 0;
3979 }
3980 
bpf_map__unpin(struct bpf_map * map,const char * path)3981 int bpf_map__unpin(struct bpf_map *map, const char *path)
3982 {
3983 	int err;
3984 
3985 	err = check_path(path);
3986 	if (err)
3987 		return err;
3988 
3989 	if (map == NULL) {
3990 		pr_warning("invalid map pointer\n");
3991 		return -EINVAL;
3992 	}
3993 
3994 	err = unlink(path);
3995 	if (err != 0)
3996 		return -errno;
3997 	pr_debug("unpinned map '%s'\n", path);
3998 
3999 	return 0;
4000 }
4001 
bpf_object__pin_maps(struct bpf_object * obj,const char * path)4002 int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
4003 {
4004 	struct bpf_map *map;
4005 	int err;
4006 
4007 	if (!obj)
4008 		return -ENOENT;
4009 
4010 	if (!obj->loaded) {
4011 		pr_warning("object not yet loaded; load it first\n");
4012 		return -ENOENT;
4013 	}
4014 
4015 	err = make_dir(path);
4016 	if (err)
4017 		return err;
4018 
4019 	bpf_object__for_each_map(map, obj) {
4020 		char buf[PATH_MAX];
4021 		int len;
4022 
4023 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
4024 			       bpf_map__name(map));
4025 		if (len < 0) {
4026 			err = -EINVAL;
4027 			goto err_unpin_maps;
4028 		} else if (len >= PATH_MAX) {
4029 			err = -ENAMETOOLONG;
4030 			goto err_unpin_maps;
4031 		}
4032 
4033 		err = bpf_map__pin(map, buf);
4034 		if (err)
4035 			goto err_unpin_maps;
4036 	}
4037 
4038 	return 0;
4039 
4040 err_unpin_maps:
4041 	while ((map = bpf_map__prev(map, obj))) {
4042 		char buf[PATH_MAX];
4043 		int len;
4044 
4045 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
4046 			       bpf_map__name(map));
4047 		if (len < 0)
4048 			continue;
4049 		else if (len >= PATH_MAX)
4050 			continue;
4051 
4052 		bpf_map__unpin(map, buf);
4053 	}
4054 
4055 	return err;
4056 }
4057 
bpf_object__unpin_maps(struct bpf_object * obj,const char * path)4058 int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
4059 {
4060 	struct bpf_map *map;
4061 	int err;
4062 
4063 	if (!obj)
4064 		return -ENOENT;
4065 
4066 	bpf_object__for_each_map(map, obj) {
4067 		char buf[PATH_MAX];
4068 		int len;
4069 
4070 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
4071 			       bpf_map__name(map));
4072 		if (len < 0)
4073 			return -EINVAL;
4074 		else if (len >= PATH_MAX)
4075 			return -ENAMETOOLONG;
4076 
4077 		err = bpf_map__unpin(map, buf);
4078 		if (err)
4079 			return err;
4080 	}
4081 
4082 	return 0;
4083 }
4084 
bpf_object__pin_programs(struct bpf_object * obj,const char * path)4085 int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
4086 {
4087 	struct bpf_program *prog;
4088 	int err;
4089 
4090 	if (!obj)
4091 		return -ENOENT;
4092 
4093 	if (!obj->loaded) {
4094 		pr_warning("object not yet loaded; load it first\n");
4095 		return -ENOENT;
4096 	}
4097 
4098 	err = make_dir(path);
4099 	if (err)
4100 		return err;
4101 
4102 	bpf_object__for_each_program(prog, obj) {
4103 		char buf[PATH_MAX];
4104 		int len;
4105 
4106 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
4107 			       prog->pin_name);
4108 		if (len < 0) {
4109 			err = -EINVAL;
4110 			goto err_unpin_programs;
4111 		} else if (len >= PATH_MAX) {
4112 			err = -ENAMETOOLONG;
4113 			goto err_unpin_programs;
4114 		}
4115 
4116 		err = bpf_program__pin(prog, buf);
4117 		if (err)
4118 			goto err_unpin_programs;
4119 	}
4120 
4121 	return 0;
4122 
4123 err_unpin_programs:
4124 	while ((prog = bpf_program__prev(prog, obj))) {
4125 		char buf[PATH_MAX];
4126 		int len;
4127 
4128 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
4129 			       prog->pin_name);
4130 		if (len < 0)
4131 			continue;
4132 		else if (len >= PATH_MAX)
4133 			continue;
4134 
4135 		bpf_program__unpin(prog, buf);
4136 	}
4137 
4138 	return err;
4139 }
4140 
bpf_object__unpin_programs(struct bpf_object * obj,const char * path)4141 int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
4142 {
4143 	struct bpf_program *prog;
4144 	int err;
4145 
4146 	if (!obj)
4147 		return -ENOENT;
4148 
4149 	bpf_object__for_each_program(prog, obj) {
4150 		char buf[PATH_MAX];
4151 		int len;
4152 
4153 		len = snprintf(buf, PATH_MAX, "%s/%s", path,
4154 			       prog->pin_name);
4155 		if (len < 0)
4156 			return -EINVAL;
4157 		else if (len >= PATH_MAX)
4158 			return -ENAMETOOLONG;
4159 
4160 		err = bpf_program__unpin(prog, buf);
4161 		if (err)
4162 			return err;
4163 	}
4164 
4165 	return 0;
4166 }
4167 
bpf_object__pin(struct bpf_object * obj,const char * path)4168 int bpf_object__pin(struct bpf_object *obj, const char *path)
4169 {
4170 	int err;
4171 
4172 	err = bpf_object__pin_maps(obj, path);
4173 	if (err)
4174 		return err;
4175 
4176 	err = bpf_object__pin_programs(obj, path);
4177 	if (err) {
4178 		bpf_object__unpin_maps(obj, path);
4179 		return err;
4180 	}
4181 
4182 	return 0;
4183 }
4184 
bpf_object__close(struct bpf_object * obj)4185 void bpf_object__close(struct bpf_object *obj)
4186 {
4187 	size_t i;
4188 
4189 	if (!obj)
4190 		return;
4191 
4192 	if (obj->clear_priv)
4193 		obj->clear_priv(obj, obj->priv);
4194 
4195 	bpf_object__elf_finish(obj);
4196 	bpf_object__unload(obj);
4197 	btf__free(obj->btf);
4198 	btf_ext__free(obj->btf_ext);
4199 
4200 	for (i = 0; i < obj->nr_maps; i++) {
4201 		zfree(&obj->maps[i].name);
4202 		if (obj->maps[i].clear_priv)
4203 			obj->maps[i].clear_priv(&obj->maps[i],
4204 						obj->maps[i].priv);
4205 		obj->maps[i].priv = NULL;
4206 		obj->maps[i].clear_priv = NULL;
4207 	}
4208 
4209 	zfree(&obj->sections.rodata);
4210 	zfree(&obj->sections.data);
4211 	zfree(&obj->maps);
4212 	obj->nr_maps = 0;
4213 
4214 	if (obj->programs && obj->nr_programs) {
4215 		for (i = 0; i < obj->nr_programs; i++)
4216 			bpf_program__exit(&obj->programs[i]);
4217 	}
4218 	zfree(&obj->programs);
4219 
4220 	list_del(&obj->list);
4221 	free(obj);
4222 }
4223 
4224 struct bpf_object *
bpf_object__next(struct bpf_object * prev)4225 bpf_object__next(struct bpf_object *prev)
4226 {
4227 	struct bpf_object *next;
4228 
4229 	if (!prev)
4230 		next = list_first_entry(&bpf_objects_list,
4231 					struct bpf_object,
4232 					list);
4233 	else
4234 		next = list_next_entry(prev, list);
4235 
4236 	/* Empty list is noticed here so don't need checking on entry. */
4237 	if (&next->list == &bpf_objects_list)
4238 		return NULL;
4239 
4240 	return next;
4241 }
4242 
bpf_object__name(const struct bpf_object * obj)4243 const char *bpf_object__name(const struct bpf_object *obj)
4244 {
4245 	return obj ? obj->path : ERR_PTR(-EINVAL);
4246 }
4247 
bpf_object__kversion(const struct bpf_object * obj)4248 unsigned int bpf_object__kversion(const struct bpf_object *obj)
4249 {
4250 	return obj ? obj->kern_version : 0;
4251 }
4252 
bpf_object__btf(const struct bpf_object * obj)4253 struct btf *bpf_object__btf(const struct bpf_object *obj)
4254 {
4255 	return obj ? obj->btf : NULL;
4256 }
4257 
bpf_object__btf_fd(const struct bpf_object * obj)4258 int bpf_object__btf_fd(const struct bpf_object *obj)
4259 {
4260 	return obj->btf ? btf__fd(obj->btf) : -1;
4261 }
4262 
bpf_object__set_priv(struct bpf_object * obj,void * priv,bpf_object_clear_priv_t clear_priv)4263 int bpf_object__set_priv(struct bpf_object *obj, void *priv,
4264 			 bpf_object_clear_priv_t clear_priv)
4265 {
4266 	if (obj->priv && obj->clear_priv)
4267 		obj->clear_priv(obj, obj->priv);
4268 
4269 	obj->priv = priv;
4270 	obj->clear_priv = clear_priv;
4271 	return 0;
4272 }
4273 
bpf_object__priv(const struct bpf_object * obj)4274 void *bpf_object__priv(const struct bpf_object *obj)
4275 {
4276 	return obj ? obj->priv : ERR_PTR(-EINVAL);
4277 }
4278 
4279 static struct bpf_program *
__bpf_program__iter(const struct bpf_program * p,const struct bpf_object * obj,bool forward)4280 __bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
4281 		    bool forward)
4282 {
4283 	size_t nr_programs = obj->nr_programs;
4284 	ssize_t idx;
4285 
4286 	if (!nr_programs)
4287 		return NULL;
4288 
4289 	if (!p)
4290 		/* Iter from the beginning */
4291 		return forward ? &obj->programs[0] :
4292 			&obj->programs[nr_programs - 1];
4293 
4294 	if (p->obj != obj) {
4295 		pr_warning("error: program handler doesn't match object\n");
4296 		return NULL;
4297 	}
4298 
4299 	idx = (p - obj->programs) + (forward ? 1 : -1);
4300 	if (idx >= obj->nr_programs || idx < 0)
4301 		return NULL;
4302 	return &obj->programs[idx];
4303 }
4304 
4305 struct bpf_program *
bpf_program__next(struct bpf_program * prev,const struct bpf_object * obj)4306 bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
4307 {
4308 	struct bpf_program *prog = prev;
4309 
4310 	do {
4311 		prog = __bpf_program__iter(prog, obj, true);
4312 	} while (prog && bpf_program__is_function_storage(prog, obj));
4313 
4314 	return prog;
4315 }
4316 
4317 struct bpf_program *
bpf_program__prev(struct bpf_program * next,const struct bpf_object * obj)4318 bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
4319 {
4320 	struct bpf_program *prog = next;
4321 
4322 	do {
4323 		prog = __bpf_program__iter(prog, obj, false);
4324 	} while (prog && bpf_program__is_function_storage(prog, obj));
4325 
4326 	return prog;
4327 }
4328 
bpf_program__set_priv(struct bpf_program * prog,void * priv,bpf_program_clear_priv_t clear_priv)4329 int bpf_program__set_priv(struct bpf_program *prog, void *priv,
4330 			  bpf_program_clear_priv_t clear_priv)
4331 {
4332 	if (prog->priv && prog->clear_priv)
4333 		prog->clear_priv(prog, prog->priv);
4334 
4335 	prog->priv = priv;
4336 	prog->clear_priv = clear_priv;
4337 	return 0;
4338 }
4339 
bpf_program__priv(const struct bpf_program * prog)4340 void *bpf_program__priv(const struct bpf_program *prog)
4341 {
4342 	return prog ? prog->priv : ERR_PTR(-EINVAL);
4343 }
4344 
bpf_program__set_ifindex(struct bpf_program * prog,__u32 ifindex)4345 void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
4346 {
4347 	prog->prog_ifindex = ifindex;
4348 }
4349 
bpf_program__title(const struct bpf_program * prog,bool needs_copy)4350 const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
4351 {
4352 	const char *title;
4353 
4354 	title = prog->section_name;
4355 	if (needs_copy) {
4356 		title = strdup(title);
4357 		if (!title) {
4358 			pr_warning("failed to strdup program title\n");
4359 			return ERR_PTR(-ENOMEM);
4360 		}
4361 	}
4362 
4363 	return title;
4364 }
4365 
bpf_program__fd(const struct bpf_program * prog)4366 int bpf_program__fd(const struct bpf_program *prog)
4367 {
4368 	return bpf_program__nth_fd(prog, 0);
4369 }
4370 
bpf_program__set_prep(struct bpf_program * prog,int nr_instances,bpf_program_prep_t prep)4371 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
4372 			  bpf_program_prep_t prep)
4373 {
4374 	int *instances_fds;
4375 
4376 	if (nr_instances <= 0 || !prep)
4377 		return -EINVAL;
4378 
4379 	if (prog->instances.nr > 0 || prog->instances.fds) {
4380 		pr_warning("Can't set pre-processor after loading\n");
4381 		return -EINVAL;
4382 	}
4383 
4384 	instances_fds = malloc(sizeof(int) * nr_instances);
4385 	if (!instances_fds) {
4386 		pr_warning("alloc memory failed for fds\n");
4387 		return -ENOMEM;
4388 	}
4389 
4390 	/* fill all fd with -1 */
4391 	memset(instances_fds, -1, sizeof(int) * nr_instances);
4392 
4393 	prog->instances.nr = nr_instances;
4394 	prog->instances.fds = instances_fds;
4395 	prog->preprocessor = prep;
4396 	return 0;
4397 }
4398 
bpf_program__nth_fd(const struct bpf_program * prog,int n)4399 int bpf_program__nth_fd(const struct bpf_program *prog, int n)
4400 {
4401 	int fd;
4402 
4403 	if (!prog)
4404 		return -EINVAL;
4405 
4406 	if (n >= prog->instances.nr || n < 0) {
4407 		pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
4408 			   n, prog->section_name, prog->instances.nr);
4409 		return -EINVAL;
4410 	}
4411 
4412 	fd = prog->instances.fds[n];
4413 	if (fd < 0) {
4414 		pr_warning("%dth instance of program '%s' is invalid\n",
4415 			   n, prog->section_name);
4416 		return -ENOENT;
4417 	}
4418 
4419 	return fd;
4420 }
4421 
bpf_program__set_type(struct bpf_program * prog,enum bpf_prog_type type)4422 void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
4423 {
4424 	prog->type = type;
4425 }
4426 
bpf_program__is_type(const struct bpf_program * prog,enum bpf_prog_type type)4427 static bool bpf_program__is_type(const struct bpf_program *prog,
4428 				 enum bpf_prog_type type)
4429 {
4430 	return prog ? (prog->type == type) : false;
4431 }
4432 
4433 #define BPF_PROG_TYPE_FNS(NAME, TYPE)				\
4434 int bpf_program__set_##NAME(struct bpf_program *prog)		\
4435 {								\
4436 	if (!prog)						\
4437 		return -EINVAL;					\
4438 	bpf_program__set_type(prog, TYPE);			\
4439 	return 0;						\
4440 }								\
4441 								\
4442 bool bpf_program__is_##NAME(const struct bpf_program *prog)	\
4443 {								\
4444 	return bpf_program__is_type(prog, TYPE);		\
4445 }								\
4446 
4447 BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
4448 BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
4449 BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
4450 BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
4451 BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
4452 BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
4453 BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
4454 BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
4455 
bpf_program__set_expected_attach_type(struct bpf_program * prog,enum bpf_attach_type type)4456 void bpf_program__set_expected_attach_type(struct bpf_program *prog,
4457 					   enum bpf_attach_type type)
4458 {
4459 	prog->expected_attach_type = type;
4460 }
4461 
4462 #define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, atype) \
4463 	{ string, sizeof(string) - 1, ptype, eatype, is_attachable, atype }
4464 
4465 /* Programs that can NOT be attached. */
4466 #define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0)
4467 
4468 /* Programs that can be attached. */
4469 #define BPF_APROG_SEC(string, ptype, atype) \
4470 	BPF_PROG_SEC_IMPL(string, ptype, 0, 1, atype)
4471 
4472 /* Programs that must specify expected attach type at load time. */
4473 #define BPF_EAPROG_SEC(string, ptype, eatype) \
4474 	BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, eatype)
4475 
4476 /* Programs that can be attached but attach type can't be identified by section
4477  * name. Kept for backward compatibility.
4478  */
4479 #define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
4480 
4481 static const struct {
4482 	const char *sec;
4483 	size_t len;
4484 	enum bpf_prog_type prog_type;
4485 	enum bpf_attach_type expected_attach_type;
4486 	int is_attachable;
4487 	enum bpf_attach_type attach_type;
4488 } section_names[] = {
4489 	BPF_PROG_SEC("socket",			BPF_PROG_TYPE_SOCKET_FILTER),
4490 	BPF_PROG_SEC("kprobe/",			BPF_PROG_TYPE_KPROBE),
4491 	BPF_PROG_SEC("kretprobe/",		BPF_PROG_TYPE_KPROBE),
4492 	BPF_PROG_SEC("classifier",		BPF_PROG_TYPE_SCHED_CLS),
4493 	BPF_PROG_SEC("action",			BPF_PROG_TYPE_SCHED_ACT),
4494 	BPF_PROG_SEC("tracepoint/",		BPF_PROG_TYPE_TRACEPOINT),
4495 	BPF_PROG_SEC("raw_tracepoint/",		BPF_PROG_TYPE_RAW_TRACEPOINT),
4496 	BPF_PROG_SEC("xdp",			BPF_PROG_TYPE_XDP),
4497 	BPF_PROG_SEC("perf_event",		BPF_PROG_TYPE_PERF_EVENT),
4498 	BPF_PROG_SEC("lwt_in",			BPF_PROG_TYPE_LWT_IN),
4499 	BPF_PROG_SEC("lwt_out",			BPF_PROG_TYPE_LWT_OUT),
4500 	BPF_PROG_SEC("lwt_xmit",		BPF_PROG_TYPE_LWT_XMIT),
4501 	BPF_PROG_SEC("lwt_seg6local",		BPF_PROG_TYPE_LWT_SEG6LOCAL),
4502 	BPF_APROG_SEC("cgroup_skb/ingress",	BPF_PROG_TYPE_CGROUP_SKB,
4503 						BPF_CGROUP_INET_INGRESS),
4504 	BPF_APROG_SEC("cgroup_skb/egress",	BPF_PROG_TYPE_CGROUP_SKB,
4505 						BPF_CGROUP_INET_EGRESS),
4506 	BPF_APROG_COMPAT("cgroup/skb",		BPF_PROG_TYPE_CGROUP_SKB),
4507 	BPF_APROG_SEC("cgroup/sock",		BPF_PROG_TYPE_CGROUP_SOCK,
4508 						BPF_CGROUP_INET_SOCK_CREATE),
4509 	BPF_EAPROG_SEC("cgroup/post_bind4",	BPF_PROG_TYPE_CGROUP_SOCK,
4510 						BPF_CGROUP_INET4_POST_BIND),
4511 	BPF_EAPROG_SEC("cgroup/post_bind6",	BPF_PROG_TYPE_CGROUP_SOCK,
4512 						BPF_CGROUP_INET6_POST_BIND),
4513 	BPF_APROG_SEC("cgroup/dev",		BPF_PROG_TYPE_CGROUP_DEVICE,
4514 						BPF_CGROUP_DEVICE),
4515 	BPF_APROG_SEC("sockops",		BPF_PROG_TYPE_SOCK_OPS,
4516 						BPF_CGROUP_SOCK_OPS),
4517 	BPF_APROG_SEC("sk_skb/stream_parser",	BPF_PROG_TYPE_SK_SKB,
4518 						BPF_SK_SKB_STREAM_PARSER),
4519 	BPF_APROG_SEC("sk_skb/stream_verdict",	BPF_PROG_TYPE_SK_SKB,
4520 						BPF_SK_SKB_STREAM_VERDICT),
4521 	BPF_APROG_COMPAT("sk_skb",		BPF_PROG_TYPE_SK_SKB),
4522 	BPF_APROG_SEC("sk_msg",			BPF_PROG_TYPE_SK_MSG,
4523 						BPF_SK_MSG_VERDICT),
4524 	BPF_APROG_SEC("lirc_mode2",		BPF_PROG_TYPE_LIRC_MODE2,
4525 						BPF_LIRC_MODE2),
4526 	BPF_APROG_SEC("flow_dissector",		BPF_PROG_TYPE_FLOW_DISSECTOR,
4527 						BPF_FLOW_DISSECTOR),
4528 	BPF_EAPROG_SEC("cgroup/bind4",		BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4529 						BPF_CGROUP_INET4_BIND),
4530 	BPF_EAPROG_SEC("cgroup/bind6",		BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4531 						BPF_CGROUP_INET6_BIND),
4532 	BPF_EAPROG_SEC("cgroup/connect4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4533 						BPF_CGROUP_INET4_CONNECT),
4534 	BPF_EAPROG_SEC("cgroup/connect6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4535 						BPF_CGROUP_INET6_CONNECT),
4536 	BPF_EAPROG_SEC("cgroup/sendmsg4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4537 						BPF_CGROUP_UDP4_SENDMSG),
4538 	BPF_EAPROG_SEC("cgroup/sendmsg6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4539 						BPF_CGROUP_UDP6_SENDMSG),
4540 	BPF_EAPROG_SEC("cgroup/recvmsg4",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4541 						BPF_CGROUP_UDP4_RECVMSG),
4542 	BPF_EAPROG_SEC("cgroup/recvmsg6",	BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
4543 						BPF_CGROUP_UDP6_RECVMSG),
4544 	BPF_EAPROG_SEC("cgroup/sysctl",		BPF_PROG_TYPE_CGROUP_SYSCTL,
4545 						BPF_CGROUP_SYSCTL),
4546 	BPF_EAPROG_SEC("cgroup/getsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
4547 						BPF_CGROUP_GETSOCKOPT),
4548 	BPF_EAPROG_SEC("cgroup/setsockopt",	BPF_PROG_TYPE_CGROUP_SOCKOPT,
4549 						BPF_CGROUP_SETSOCKOPT),
4550 };
4551 
4552 #undef BPF_PROG_SEC_IMPL
4553 #undef BPF_PROG_SEC
4554 #undef BPF_APROG_SEC
4555 #undef BPF_EAPROG_SEC
4556 #undef BPF_APROG_COMPAT
4557 
4558 #define MAX_TYPE_NAME_SIZE 32
4559 
libbpf_get_type_names(bool attach_type)4560 static char *libbpf_get_type_names(bool attach_type)
4561 {
4562 	int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE;
4563 	char *buf;
4564 
4565 	buf = malloc(len);
4566 	if (!buf)
4567 		return NULL;
4568 
4569 	buf[0] = '\0';
4570 	/* Forge string buf with all available names */
4571 	for (i = 0; i < ARRAY_SIZE(section_names); i++) {
4572 		if (attach_type && !section_names[i].is_attachable)
4573 			continue;
4574 
4575 		if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) {
4576 			free(buf);
4577 			return NULL;
4578 		}
4579 		strcat(buf, " ");
4580 		strcat(buf, section_names[i].sec);
4581 	}
4582 
4583 	return buf;
4584 }
4585 
libbpf_prog_type_by_name(const char * name,enum bpf_prog_type * prog_type,enum bpf_attach_type * expected_attach_type)4586 int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
4587 			     enum bpf_attach_type *expected_attach_type)
4588 {
4589 	char *type_names;
4590 	int i;
4591 
4592 	if (!name)
4593 		return -EINVAL;
4594 
4595 	for (i = 0; i < ARRAY_SIZE(section_names); i++) {
4596 		if (strncmp(name, section_names[i].sec, section_names[i].len))
4597 			continue;
4598 		*prog_type = section_names[i].prog_type;
4599 		*expected_attach_type = section_names[i].expected_attach_type;
4600 		return 0;
4601 	}
4602 	pr_warning("failed to guess program type based on ELF section name '%s'\n", name);
4603 	type_names = libbpf_get_type_names(false);
4604 	if (type_names != NULL) {
4605 		pr_info("supported section(type) names are:%s\n", type_names);
4606 		free(type_names);
4607 	}
4608 
4609 	return -EINVAL;
4610 }
4611 
libbpf_attach_type_by_name(const char * name,enum bpf_attach_type * attach_type)4612 int libbpf_attach_type_by_name(const char *name,
4613 			       enum bpf_attach_type *attach_type)
4614 {
4615 	char *type_names;
4616 	int i;
4617 
4618 	if (!name)
4619 		return -EINVAL;
4620 
4621 	for (i = 0; i < ARRAY_SIZE(section_names); i++) {
4622 		if (strncmp(name, section_names[i].sec, section_names[i].len))
4623 			continue;
4624 		if (!section_names[i].is_attachable)
4625 			return -EINVAL;
4626 		*attach_type = section_names[i].attach_type;
4627 		return 0;
4628 	}
4629 	pr_warning("failed to guess attach type based on ELF section name '%s'\n", name);
4630 	type_names = libbpf_get_type_names(true);
4631 	if (type_names != NULL) {
4632 		pr_info("attachable section(type) names are:%s\n", type_names);
4633 		free(type_names);
4634 	}
4635 
4636 	return -EINVAL;
4637 }
4638 
4639 static int
bpf_program__identify_section(struct bpf_program * prog,enum bpf_prog_type * prog_type,enum bpf_attach_type * expected_attach_type)4640 bpf_program__identify_section(struct bpf_program *prog,
4641 			      enum bpf_prog_type *prog_type,
4642 			      enum bpf_attach_type *expected_attach_type)
4643 {
4644 	return libbpf_prog_type_by_name(prog->section_name, prog_type,
4645 					expected_attach_type);
4646 }
4647 
bpf_map__fd(const struct bpf_map * map)4648 int bpf_map__fd(const struct bpf_map *map)
4649 {
4650 	return map ? map->fd : -EINVAL;
4651 }
4652 
bpf_map__def(const struct bpf_map * map)4653 const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
4654 {
4655 	return map ? &map->def : ERR_PTR(-EINVAL);
4656 }
4657 
bpf_map__name(const struct bpf_map * map)4658 const char *bpf_map__name(const struct bpf_map *map)
4659 {
4660 	return map ? map->name : NULL;
4661 }
4662 
bpf_map__btf_key_type_id(const struct bpf_map * map)4663 __u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
4664 {
4665 	return map ? map->btf_key_type_id : 0;
4666 }
4667 
bpf_map__btf_value_type_id(const struct bpf_map * map)4668 __u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
4669 {
4670 	return map ? map->btf_value_type_id : 0;
4671 }
4672 
bpf_map__set_priv(struct bpf_map * map,void * priv,bpf_map_clear_priv_t clear_priv)4673 int bpf_map__set_priv(struct bpf_map *map, void *priv,
4674 		     bpf_map_clear_priv_t clear_priv)
4675 {
4676 	if (!map)
4677 		return -EINVAL;
4678 
4679 	if (map->priv) {
4680 		if (map->clear_priv)
4681 			map->clear_priv(map, map->priv);
4682 	}
4683 
4684 	map->priv = priv;
4685 	map->clear_priv = clear_priv;
4686 	return 0;
4687 }
4688 
bpf_map__priv(const struct bpf_map * map)4689 void *bpf_map__priv(const struct bpf_map *map)
4690 {
4691 	return map ? map->priv : ERR_PTR(-EINVAL);
4692 }
4693 
bpf_map__is_offload_neutral(const struct bpf_map * map)4694 bool bpf_map__is_offload_neutral(const struct bpf_map *map)
4695 {
4696 	return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
4697 }
4698 
bpf_map__is_internal(const struct bpf_map * map)4699 bool bpf_map__is_internal(const struct bpf_map *map)
4700 {
4701 	return map->libbpf_type != LIBBPF_MAP_UNSPEC;
4702 }
4703 
bpf_map__set_ifindex(struct bpf_map * map,__u32 ifindex)4704 void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
4705 {
4706 	map->map_ifindex = ifindex;
4707 }
4708 
bpf_map__set_inner_map_fd(struct bpf_map * map,int fd)4709 int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
4710 {
4711 	if (!bpf_map_type__is_map_in_map(map->def.type)) {
4712 		pr_warning("error: unsupported map type\n");
4713 		return -EINVAL;
4714 	}
4715 	if (map->inner_map_fd != -1) {
4716 		pr_warning("error: inner_map_fd already specified\n");
4717 		return -EINVAL;
4718 	}
4719 	map->inner_map_fd = fd;
4720 	return 0;
4721 }
4722 
4723 static struct bpf_map *
__bpf_map__iter(const struct bpf_map * m,const struct bpf_object * obj,int i)4724 __bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
4725 {
4726 	ssize_t idx;
4727 	struct bpf_map *s, *e;
4728 
4729 	if (!obj || !obj->maps)
4730 		return NULL;
4731 
4732 	s = obj->maps;
4733 	e = obj->maps + obj->nr_maps;
4734 
4735 	if ((m < s) || (m >= e)) {
4736 		pr_warning("error in %s: map handler doesn't belong to object\n",
4737 			   __func__);
4738 		return NULL;
4739 	}
4740 
4741 	idx = (m - obj->maps) + i;
4742 	if (idx >= obj->nr_maps || idx < 0)
4743 		return NULL;
4744 	return &obj->maps[idx];
4745 }
4746 
4747 struct bpf_map *
bpf_map__next(const struct bpf_map * prev,const struct bpf_object * obj)4748 bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
4749 {
4750 	if (prev == NULL)
4751 		return obj->maps;
4752 
4753 	return __bpf_map__iter(prev, obj, 1);
4754 }
4755 
4756 struct bpf_map *
bpf_map__prev(const struct bpf_map * next,const struct bpf_object * obj)4757 bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
4758 {
4759 	if (next == NULL) {
4760 		if (!obj->nr_maps)
4761 			return NULL;
4762 		return obj->maps + obj->nr_maps - 1;
4763 	}
4764 
4765 	return __bpf_map__iter(next, obj, -1);
4766 }
4767 
4768 struct bpf_map *
bpf_object__find_map_by_name(const struct bpf_object * obj,const char * name)4769 bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
4770 {
4771 	struct bpf_map *pos;
4772 
4773 	bpf_object__for_each_map(pos, obj) {
4774 		if (pos->name && !strcmp(pos->name, name))
4775 			return pos;
4776 	}
4777 	return NULL;
4778 }
4779 
4780 int
bpf_object__find_map_fd_by_name(const struct bpf_object * obj,const char * name)4781 bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
4782 {
4783 	return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
4784 }
4785 
4786 struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object * obj,size_t offset)4787 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
4788 {
4789 	return ERR_PTR(-ENOTSUP);
4790 }
4791 
libbpf_get_error(const void * ptr)4792 long libbpf_get_error(const void *ptr)
4793 {
4794 	return PTR_ERR_OR_ZERO(ptr);
4795 }
4796 
bpf_prog_load(const char * file,enum bpf_prog_type type,struct bpf_object ** pobj,int * prog_fd)4797 int bpf_prog_load(const char *file, enum bpf_prog_type type,
4798 		  struct bpf_object **pobj, int *prog_fd)
4799 {
4800 	struct bpf_prog_load_attr attr;
4801 
4802 	memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
4803 	attr.file = file;
4804 	attr.prog_type = type;
4805 	attr.expected_attach_type = 0;
4806 
4807 	return bpf_prog_load_xattr(&attr, pobj, prog_fd);
4808 }
4809 
bpf_prog_load_xattr(const struct bpf_prog_load_attr * attr,struct bpf_object ** pobj,int * prog_fd)4810 int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
4811 			struct bpf_object **pobj, int *prog_fd)
4812 {
4813 	struct bpf_object_open_attr open_attr = {};
4814 	struct bpf_program *prog, *first_prog = NULL;
4815 	enum bpf_attach_type expected_attach_type;
4816 	enum bpf_prog_type prog_type;
4817 	struct bpf_object *obj;
4818 	struct bpf_map *map;
4819 	int err;
4820 
4821 	if (!attr)
4822 		return -EINVAL;
4823 	if (!attr->file)
4824 		return -EINVAL;
4825 
4826 	open_attr.file = attr->file;
4827 	open_attr.prog_type = attr->prog_type;
4828 
4829 	obj = bpf_object__open_xattr(&open_attr);
4830 	if (IS_ERR_OR_NULL(obj))
4831 		return -ENOENT;
4832 
4833 	bpf_object__for_each_program(prog, obj) {
4834 		/*
4835 		 * If type is not specified, try to guess it based on
4836 		 * section name.
4837 		 */
4838 		prog_type = attr->prog_type;
4839 		prog->prog_ifindex = attr->ifindex;
4840 		expected_attach_type = attr->expected_attach_type;
4841 		if (prog_type == BPF_PROG_TYPE_UNSPEC) {
4842 			err = bpf_program__identify_section(prog, &prog_type,
4843 							    &expected_attach_type);
4844 			if (err < 0) {
4845 				bpf_object__close(obj);
4846 				return -EINVAL;
4847 			}
4848 		}
4849 
4850 		bpf_program__set_type(prog, prog_type);
4851 		bpf_program__set_expected_attach_type(prog,
4852 						      expected_attach_type);
4853 
4854 		prog->log_level = attr->log_level;
4855 		prog->prog_flags = attr->prog_flags;
4856 		if (!first_prog)
4857 			first_prog = prog;
4858 	}
4859 
4860 	bpf_object__for_each_map(map, obj) {
4861 		if (!bpf_map__is_offload_neutral(map))
4862 			map->map_ifindex = attr->ifindex;
4863 	}
4864 
4865 	if (!first_prog) {
4866 		pr_warning("object file doesn't contain bpf program\n");
4867 		bpf_object__close(obj);
4868 		return -ENOENT;
4869 	}
4870 
4871 	err = bpf_object__load(obj);
4872 	if (err) {
4873 		bpf_object__close(obj);
4874 		return -EINVAL;
4875 	}
4876 
4877 	*pobj = obj;
4878 	*prog_fd = bpf_program__fd(first_prog);
4879 	return 0;
4880 }
4881 
4882 struct bpf_link {
4883 	int (*destroy)(struct bpf_link *link);
4884 };
4885 
bpf_link__destroy(struct bpf_link * link)4886 int bpf_link__destroy(struct bpf_link *link)
4887 {
4888 	int err;
4889 
4890 	if (!link)
4891 		return 0;
4892 
4893 	err = link->destroy(link);
4894 	free(link);
4895 
4896 	return err;
4897 }
4898 
4899 struct bpf_link_fd {
4900 	struct bpf_link link; /* has to be at the top of struct */
4901 	int fd; /* hook FD */
4902 };
4903 
bpf_link__destroy_perf_event(struct bpf_link * link)4904 static int bpf_link__destroy_perf_event(struct bpf_link *link)
4905 {
4906 	struct bpf_link_fd *l = (void *)link;
4907 	int err;
4908 
4909 	err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0);
4910 	if (err)
4911 		err = -errno;
4912 
4913 	close(l->fd);
4914 	return err;
4915 }
4916 
bpf_program__attach_perf_event(struct bpf_program * prog,int pfd)4917 struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
4918 						int pfd)
4919 {
4920 	char errmsg[STRERR_BUFSIZE];
4921 	struct bpf_link_fd *link;
4922 	int prog_fd, err;
4923 
4924 	if (pfd < 0) {
4925 		pr_warning("program '%s': invalid perf event FD %d\n",
4926 			   bpf_program__title(prog, false), pfd);
4927 		return ERR_PTR(-EINVAL);
4928 	}
4929 	prog_fd = bpf_program__fd(prog);
4930 	if (prog_fd < 0) {
4931 		pr_warning("program '%s': can't attach BPF program w/o FD (did you load it?)\n",
4932 			   bpf_program__title(prog, false));
4933 		return ERR_PTR(-EINVAL);
4934 	}
4935 
4936 	link = malloc(sizeof(*link));
4937 	if (!link)
4938 		return ERR_PTR(-ENOMEM);
4939 	link->link.destroy = &bpf_link__destroy_perf_event;
4940 	link->fd = pfd;
4941 
4942 	if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
4943 		err = -errno;
4944 		free(link);
4945 		pr_warning("program '%s': failed to attach to pfd %d: %s\n",
4946 			   bpf_program__title(prog, false), pfd,
4947 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
4948 		return ERR_PTR(err);
4949 	}
4950 	if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
4951 		err = -errno;
4952 		free(link);
4953 		pr_warning("program '%s': failed to enable pfd %d: %s\n",
4954 			   bpf_program__title(prog, false), pfd,
4955 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
4956 		return ERR_PTR(err);
4957 	}
4958 	return (struct bpf_link *)link;
4959 }
4960 
4961 /*
4962  * this function is expected to parse integer in the range of [0, 2^31-1] from
4963  * given file using scanf format string fmt. If actual parsed value is
4964  * negative, the result might be indistinguishable from error
4965  */
parse_uint_from_file(const char * file,const char * fmt)4966 static int parse_uint_from_file(const char *file, const char *fmt)
4967 {
4968 	char buf[STRERR_BUFSIZE];
4969 	int err, ret;
4970 	FILE *f;
4971 
4972 	f = fopen(file, "r");
4973 	if (!f) {
4974 		err = -errno;
4975 		pr_debug("failed to open '%s': %s\n", file,
4976 			 libbpf_strerror_r(err, buf, sizeof(buf)));
4977 		return err;
4978 	}
4979 	err = fscanf(f, fmt, &ret);
4980 	if (err != 1) {
4981 		err = err == EOF ? -EIO : -errno;
4982 		pr_debug("failed to parse '%s': %s\n", file,
4983 			libbpf_strerror_r(err, buf, sizeof(buf)));
4984 		fclose(f);
4985 		return err;
4986 	}
4987 	fclose(f);
4988 	return ret;
4989 }
4990 
determine_kprobe_perf_type(void)4991 static int determine_kprobe_perf_type(void)
4992 {
4993 	const char *file = "/sys/bus/event_source/devices/kprobe/type";
4994 
4995 	return parse_uint_from_file(file, "%d\n");
4996 }
4997 
determine_uprobe_perf_type(void)4998 static int determine_uprobe_perf_type(void)
4999 {
5000 	const char *file = "/sys/bus/event_source/devices/uprobe/type";
5001 
5002 	return parse_uint_from_file(file, "%d\n");
5003 }
5004 
determine_kprobe_retprobe_bit(void)5005 static int determine_kprobe_retprobe_bit(void)
5006 {
5007 	const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
5008 
5009 	return parse_uint_from_file(file, "config:%d\n");
5010 }
5011 
determine_uprobe_retprobe_bit(void)5012 static int determine_uprobe_retprobe_bit(void)
5013 {
5014 	const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
5015 
5016 	return parse_uint_from_file(file, "config:%d\n");
5017 }
5018 
perf_event_open_probe(bool uprobe,bool retprobe,const char * name,uint64_t offset,int pid)5019 static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
5020 				 uint64_t offset, int pid)
5021 {
5022 	struct perf_event_attr attr = {};
5023 	char errmsg[STRERR_BUFSIZE];
5024 	int type, pfd, err;
5025 
5026 	type = uprobe ? determine_uprobe_perf_type()
5027 		      : determine_kprobe_perf_type();
5028 	if (type < 0) {
5029 		pr_warning("failed to determine %s perf type: %s\n",
5030 			   uprobe ? "uprobe" : "kprobe",
5031 			   libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
5032 		return type;
5033 	}
5034 	if (retprobe) {
5035 		int bit = uprobe ? determine_uprobe_retprobe_bit()
5036 				 : determine_kprobe_retprobe_bit();
5037 
5038 		if (bit < 0) {
5039 			pr_warning("failed to determine %s retprobe bit: %s\n",
5040 				   uprobe ? "uprobe" : "kprobe",
5041 				   libbpf_strerror_r(bit, errmsg,
5042 						     sizeof(errmsg)));
5043 			return bit;
5044 		}
5045 		attr.config |= 1 << bit;
5046 	}
5047 	attr.size = sizeof(attr);
5048 	attr.type = type;
5049 	attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
5050 	attr.config2 = offset;		 /* kprobe_addr or probe_offset */
5051 
5052 	/* pid filter is meaningful only for uprobes */
5053 	pfd = syscall(__NR_perf_event_open, &attr,
5054 		      pid < 0 ? -1 : pid /* pid */,
5055 		      pid == -1 ? 0 : -1 /* cpu */,
5056 		      -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
5057 	if (pfd < 0) {
5058 		err = -errno;
5059 		pr_warning("%s perf_event_open() failed: %s\n",
5060 			   uprobe ? "uprobe" : "kprobe",
5061 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5062 		return err;
5063 	}
5064 	return pfd;
5065 }
5066 
bpf_program__attach_kprobe(struct bpf_program * prog,bool retprobe,const char * func_name)5067 struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
5068 					    bool retprobe,
5069 					    const char *func_name)
5070 {
5071 	char errmsg[STRERR_BUFSIZE];
5072 	struct bpf_link *link;
5073 	int pfd, err;
5074 
5075 	pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
5076 				    0 /* offset */, -1 /* pid */);
5077 	if (pfd < 0) {
5078 		pr_warning("program '%s': failed to create %s '%s' perf event: %s\n",
5079 			   bpf_program__title(prog, false),
5080 			   retprobe ? "kretprobe" : "kprobe", func_name,
5081 			   libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5082 		return ERR_PTR(pfd);
5083 	}
5084 	link = bpf_program__attach_perf_event(prog, pfd);
5085 	if (IS_ERR(link)) {
5086 		close(pfd);
5087 		err = PTR_ERR(link);
5088 		pr_warning("program '%s': failed to attach to %s '%s': %s\n",
5089 			   bpf_program__title(prog, false),
5090 			   retprobe ? "kretprobe" : "kprobe", func_name,
5091 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5092 		return link;
5093 	}
5094 	return link;
5095 }
5096 
bpf_program__attach_uprobe(struct bpf_program * prog,bool retprobe,pid_t pid,const char * binary_path,size_t func_offset)5097 struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
5098 					    bool retprobe, pid_t pid,
5099 					    const char *binary_path,
5100 					    size_t func_offset)
5101 {
5102 	char errmsg[STRERR_BUFSIZE];
5103 	struct bpf_link *link;
5104 	int pfd, err;
5105 
5106 	pfd = perf_event_open_probe(true /* uprobe */, retprobe,
5107 				    binary_path, func_offset, pid);
5108 	if (pfd < 0) {
5109 		pr_warning("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
5110 			   bpf_program__title(prog, false),
5111 			   retprobe ? "uretprobe" : "uprobe",
5112 			   binary_path, func_offset,
5113 			   libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5114 		return ERR_PTR(pfd);
5115 	}
5116 	link = bpf_program__attach_perf_event(prog, pfd);
5117 	if (IS_ERR(link)) {
5118 		close(pfd);
5119 		err = PTR_ERR(link);
5120 		pr_warning("program '%s': failed to attach to %s '%s:0x%zx': %s\n",
5121 			   bpf_program__title(prog, false),
5122 			   retprobe ? "uretprobe" : "uprobe",
5123 			   binary_path, func_offset,
5124 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5125 		return link;
5126 	}
5127 	return link;
5128 }
5129 
determine_tracepoint_id(const char * tp_category,const char * tp_name)5130 static int determine_tracepoint_id(const char *tp_category,
5131 				   const char *tp_name)
5132 {
5133 	char file[PATH_MAX];
5134 	int ret;
5135 
5136 	ret = snprintf(file, sizeof(file),
5137 		       "/sys/kernel/debug/tracing/events/%s/%s/id",
5138 		       tp_category, tp_name);
5139 	if (ret < 0)
5140 		return -errno;
5141 	if (ret >= sizeof(file)) {
5142 		pr_debug("tracepoint %s/%s path is too long\n",
5143 			 tp_category, tp_name);
5144 		return -E2BIG;
5145 	}
5146 	return parse_uint_from_file(file, "%d\n");
5147 }
5148 
perf_event_open_tracepoint(const char * tp_category,const char * tp_name)5149 static int perf_event_open_tracepoint(const char *tp_category,
5150 				      const char *tp_name)
5151 {
5152 	struct perf_event_attr attr = {};
5153 	char errmsg[STRERR_BUFSIZE];
5154 	int tp_id, pfd, err;
5155 
5156 	tp_id = determine_tracepoint_id(tp_category, tp_name);
5157 	if (tp_id < 0) {
5158 		pr_warning("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
5159 			   tp_category, tp_name,
5160 			   libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
5161 		return tp_id;
5162 	}
5163 
5164 	attr.type = PERF_TYPE_TRACEPOINT;
5165 	attr.size = sizeof(attr);
5166 	attr.config = tp_id;
5167 
5168 	pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
5169 		      -1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
5170 	if (pfd < 0) {
5171 		err = -errno;
5172 		pr_warning("tracepoint '%s/%s' perf_event_open() failed: %s\n",
5173 			   tp_category, tp_name,
5174 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5175 		return err;
5176 	}
5177 	return pfd;
5178 }
5179 
bpf_program__attach_tracepoint(struct bpf_program * prog,const char * tp_category,const char * tp_name)5180 struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
5181 						const char *tp_category,
5182 						const char *tp_name)
5183 {
5184 	char errmsg[STRERR_BUFSIZE];
5185 	struct bpf_link *link;
5186 	int pfd, err;
5187 
5188 	pfd = perf_event_open_tracepoint(tp_category, tp_name);
5189 	if (pfd < 0) {
5190 		pr_warning("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
5191 			   bpf_program__title(prog, false),
5192 			   tp_category, tp_name,
5193 			   libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5194 		return ERR_PTR(pfd);
5195 	}
5196 	link = bpf_program__attach_perf_event(prog, pfd);
5197 	if (IS_ERR(link)) {
5198 		close(pfd);
5199 		err = PTR_ERR(link);
5200 		pr_warning("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
5201 			   bpf_program__title(prog, false),
5202 			   tp_category, tp_name,
5203 			   libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
5204 		return link;
5205 	}
5206 	return link;
5207 }
5208 
bpf_link__destroy_fd(struct bpf_link * link)5209 static int bpf_link__destroy_fd(struct bpf_link *link)
5210 {
5211 	struct bpf_link_fd *l = (void *)link;
5212 
5213 	return close(l->fd);
5214 }
5215 
bpf_program__attach_raw_tracepoint(struct bpf_program * prog,const char * tp_name)5216 struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
5217 						    const char *tp_name)
5218 {
5219 	char errmsg[STRERR_BUFSIZE];
5220 	struct bpf_link_fd *link;
5221 	int prog_fd, pfd;
5222 
5223 	prog_fd = bpf_program__fd(prog);
5224 	if (prog_fd < 0) {
5225 		pr_warning("program '%s': can't attach before loaded\n",
5226 			   bpf_program__title(prog, false));
5227 		return ERR_PTR(-EINVAL);
5228 	}
5229 
5230 	link = malloc(sizeof(*link));
5231 	if (!link)
5232 		return ERR_PTR(-ENOMEM);
5233 	link->link.destroy = &bpf_link__destroy_fd;
5234 
5235 	pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
5236 	if (pfd < 0) {
5237 		pfd = -errno;
5238 		free(link);
5239 		pr_warning("program '%s': failed to attach to raw tracepoint '%s': %s\n",
5240 			   bpf_program__title(prog, false), tp_name,
5241 			   libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
5242 		return ERR_PTR(pfd);
5243 	}
5244 	link->fd = pfd;
5245 	return (struct bpf_link *)link;
5246 }
5247 
5248 enum bpf_perf_event_ret
bpf_perf_event_read_simple(void * mmap_mem,size_t mmap_size,size_t page_size,void ** copy_mem,size_t * copy_size,bpf_perf_event_print_t fn,void * private_data)5249 bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
5250 			   void **copy_mem, size_t *copy_size,
5251 			   bpf_perf_event_print_t fn, void *private_data)
5252 {
5253 	struct perf_event_mmap_page *header = mmap_mem;
5254 	__u64 data_head = ring_buffer_read_head(header);
5255 	__u64 data_tail = header->data_tail;
5256 	void *base = ((__u8 *)header) + page_size;
5257 	int ret = LIBBPF_PERF_EVENT_CONT;
5258 	struct perf_event_header *ehdr;
5259 	size_t ehdr_size;
5260 
5261 	while (data_head != data_tail) {
5262 		ehdr = base + (data_tail & (mmap_size - 1));
5263 		ehdr_size = ehdr->size;
5264 
5265 		if (((void *)ehdr) + ehdr_size > base + mmap_size) {
5266 			void *copy_start = ehdr;
5267 			size_t len_first = base + mmap_size - copy_start;
5268 			size_t len_secnd = ehdr_size - len_first;
5269 
5270 			if (*copy_size < ehdr_size) {
5271 				free(*copy_mem);
5272 				*copy_mem = malloc(ehdr_size);
5273 				if (!*copy_mem) {
5274 					*copy_size = 0;
5275 					ret = LIBBPF_PERF_EVENT_ERROR;
5276 					break;
5277 				}
5278 				*copy_size = ehdr_size;
5279 			}
5280 
5281 			memcpy(*copy_mem, copy_start, len_first);
5282 			memcpy(*copy_mem + len_first, base, len_secnd);
5283 			ehdr = *copy_mem;
5284 		}
5285 
5286 		ret = fn(ehdr, private_data);
5287 		data_tail += ehdr_size;
5288 		if (ret != LIBBPF_PERF_EVENT_CONT)
5289 			break;
5290 	}
5291 
5292 	ring_buffer_write_tail(header, data_tail);
5293 	return ret;
5294 }
5295 
5296 struct perf_buffer;
5297 
5298 struct perf_buffer_params {
5299 	struct perf_event_attr *attr;
5300 	/* if event_cb is specified, it takes precendence */
5301 	perf_buffer_event_fn event_cb;
5302 	/* sample_cb and lost_cb are higher-level common-case callbacks */
5303 	perf_buffer_sample_fn sample_cb;
5304 	perf_buffer_lost_fn lost_cb;
5305 	void *ctx;
5306 	int cpu_cnt;
5307 	int *cpus;
5308 	int *map_keys;
5309 };
5310 
5311 struct perf_cpu_buf {
5312 	struct perf_buffer *pb;
5313 	void *base; /* mmap()'ed memory */
5314 	void *buf; /* for reconstructing segmented data */
5315 	size_t buf_size;
5316 	int fd;
5317 	int cpu;
5318 	int map_key;
5319 };
5320 
5321 struct perf_buffer {
5322 	perf_buffer_event_fn event_cb;
5323 	perf_buffer_sample_fn sample_cb;
5324 	perf_buffer_lost_fn lost_cb;
5325 	void *ctx; /* passed into callbacks */
5326 
5327 	size_t page_size;
5328 	size_t mmap_size;
5329 	struct perf_cpu_buf **cpu_bufs;
5330 	struct epoll_event *events;
5331 	int cpu_cnt;
5332 	int epoll_fd; /* perf event FD */
5333 	int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
5334 };
5335 
perf_buffer__free_cpu_buf(struct perf_buffer * pb,struct perf_cpu_buf * cpu_buf)5336 static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
5337 				      struct perf_cpu_buf *cpu_buf)
5338 {
5339 	if (!cpu_buf)
5340 		return;
5341 	if (cpu_buf->base &&
5342 	    munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
5343 		pr_warning("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
5344 	if (cpu_buf->fd >= 0) {
5345 		ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
5346 		close(cpu_buf->fd);
5347 	}
5348 	free(cpu_buf->buf);
5349 	free(cpu_buf);
5350 }
5351 
perf_buffer__free(struct perf_buffer * pb)5352 void perf_buffer__free(struct perf_buffer *pb)
5353 {
5354 	int i;
5355 
5356 	if (!pb)
5357 		return;
5358 	if (pb->cpu_bufs) {
5359 		for (i = 0; i < pb->cpu_cnt && pb->cpu_bufs[i]; i++) {
5360 			struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
5361 
5362 			bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
5363 			perf_buffer__free_cpu_buf(pb, cpu_buf);
5364 		}
5365 		free(pb->cpu_bufs);
5366 	}
5367 	if (pb->epoll_fd >= 0)
5368 		close(pb->epoll_fd);
5369 	free(pb->events);
5370 	free(pb);
5371 }
5372 
5373 static struct perf_cpu_buf *
perf_buffer__open_cpu_buf(struct perf_buffer * pb,struct perf_event_attr * attr,int cpu,int map_key)5374 perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
5375 			  int cpu, int map_key)
5376 {
5377 	struct perf_cpu_buf *cpu_buf;
5378 	char msg[STRERR_BUFSIZE];
5379 	int err;
5380 
5381 	cpu_buf = calloc(1, sizeof(*cpu_buf));
5382 	if (!cpu_buf)
5383 		return ERR_PTR(-ENOMEM);
5384 
5385 	cpu_buf->pb = pb;
5386 	cpu_buf->cpu = cpu;
5387 	cpu_buf->map_key = map_key;
5388 
5389 	cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
5390 			      -1, PERF_FLAG_FD_CLOEXEC);
5391 	if (cpu_buf->fd < 0) {
5392 		err = -errno;
5393 		pr_warning("failed to open perf buffer event on cpu #%d: %s\n",
5394 			   cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
5395 		goto error;
5396 	}
5397 
5398 	cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
5399 			     PROT_READ | PROT_WRITE, MAP_SHARED,
5400 			     cpu_buf->fd, 0);
5401 	if (cpu_buf->base == MAP_FAILED) {
5402 		cpu_buf->base = NULL;
5403 		err = -errno;
5404 		pr_warning("failed to mmap perf buffer on cpu #%d: %s\n",
5405 			   cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
5406 		goto error;
5407 	}
5408 
5409 	if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
5410 		err = -errno;
5411 		pr_warning("failed to enable perf buffer event on cpu #%d: %s\n",
5412 			   cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
5413 		goto error;
5414 	}
5415 
5416 	return cpu_buf;
5417 
5418 error:
5419 	perf_buffer__free_cpu_buf(pb, cpu_buf);
5420 	return (struct perf_cpu_buf *)ERR_PTR(err);
5421 }
5422 
5423 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
5424 					      struct perf_buffer_params *p);
5425 
perf_buffer__new(int map_fd,size_t page_cnt,const struct perf_buffer_opts * opts)5426 struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
5427 				     const struct perf_buffer_opts *opts)
5428 {
5429 	struct perf_buffer_params p = {};
5430 	struct perf_event_attr attr = { 0, };
5431 
5432 	attr.config = PERF_COUNT_SW_BPF_OUTPUT,
5433 	attr.type = PERF_TYPE_SOFTWARE;
5434 	attr.sample_type = PERF_SAMPLE_RAW;
5435 	attr.sample_period = 1;
5436 	attr.wakeup_events = 1;
5437 
5438 	p.attr = &attr;
5439 	p.sample_cb = opts ? opts->sample_cb : NULL;
5440 	p.lost_cb = opts ? opts->lost_cb : NULL;
5441 	p.ctx = opts ? opts->ctx : NULL;
5442 
5443 	return __perf_buffer__new(map_fd, page_cnt, &p);
5444 }
5445 
5446 struct perf_buffer *
perf_buffer__new_raw(int map_fd,size_t page_cnt,const struct perf_buffer_raw_opts * opts)5447 perf_buffer__new_raw(int map_fd, size_t page_cnt,
5448 		     const struct perf_buffer_raw_opts *opts)
5449 {
5450 	struct perf_buffer_params p = {};
5451 
5452 	p.attr = opts->attr;
5453 	p.event_cb = opts->event_cb;
5454 	p.ctx = opts->ctx;
5455 	p.cpu_cnt = opts->cpu_cnt;
5456 	p.cpus = opts->cpus;
5457 	p.map_keys = opts->map_keys;
5458 
5459 	return __perf_buffer__new(map_fd, page_cnt, &p);
5460 }
5461 
__perf_buffer__new(int map_fd,size_t page_cnt,struct perf_buffer_params * p)5462 static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
5463 					      struct perf_buffer_params *p)
5464 {
5465 	struct bpf_map_info map = {};
5466 	char msg[STRERR_BUFSIZE];
5467 	struct perf_buffer *pb;
5468 	__u32 map_info_len;
5469 	int err, i;
5470 
5471 	if (page_cnt & (page_cnt - 1)) {
5472 		pr_warning("page count should be power of two, but is %zu\n",
5473 			   page_cnt);
5474 		return ERR_PTR(-EINVAL);
5475 	}
5476 
5477 	map_info_len = sizeof(map);
5478 	err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
5479 	if (err) {
5480 		err = -errno;
5481 		pr_warning("failed to get map info for map FD %d: %s\n",
5482 			   map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
5483 		return ERR_PTR(err);
5484 	}
5485 
5486 	if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
5487 		pr_warning("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
5488 			   map.name);
5489 		return ERR_PTR(-EINVAL);
5490 	}
5491 
5492 	pb = calloc(1, sizeof(*pb));
5493 	if (!pb)
5494 		return ERR_PTR(-ENOMEM);
5495 
5496 	pb->event_cb = p->event_cb;
5497 	pb->sample_cb = p->sample_cb;
5498 	pb->lost_cb = p->lost_cb;
5499 	pb->ctx = p->ctx;
5500 
5501 	pb->page_size = getpagesize();
5502 	pb->mmap_size = pb->page_size * page_cnt;
5503 	pb->map_fd = map_fd;
5504 
5505 	pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
5506 	if (pb->epoll_fd < 0) {
5507 		err = -errno;
5508 		pr_warning("failed to create epoll instance: %s\n",
5509 			   libbpf_strerror_r(err, msg, sizeof(msg)));
5510 		goto error;
5511 	}
5512 
5513 	if (p->cpu_cnt > 0) {
5514 		pb->cpu_cnt = p->cpu_cnt;
5515 	} else {
5516 		pb->cpu_cnt = libbpf_num_possible_cpus();
5517 		if (pb->cpu_cnt < 0) {
5518 			err = pb->cpu_cnt;
5519 			goto error;
5520 		}
5521 		if (map.max_entries < pb->cpu_cnt)
5522 			pb->cpu_cnt = map.max_entries;
5523 	}
5524 
5525 	pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
5526 	if (!pb->events) {
5527 		err = -ENOMEM;
5528 		pr_warning("failed to allocate events: out of memory\n");
5529 		goto error;
5530 	}
5531 	pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
5532 	if (!pb->cpu_bufs) {
5533 		err = -ENOMEM;
5534 		pr_warning("failed to allocate buffers: out of memory\n");
5535 		goto error;
5536 	}
5537 
5538 	for (i = 0; i < pb->cpu_cnt; i++) {
5539 		struct perf_cpu_buf *cpu_buf;
5540 		int cpu, map_key;
5541 
5542 		cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
5543 		map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
5544 
5545 		cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
5546 		if (IS_ERR(cpu_buf)) {
5547 			err = PTR_ERR(cpu_buf);
5548 			goto error;
5549 		}
5550 
5551 		pb->cpu_bufs[i] = cpu_buf;
5552 
5553 		err = bpf_map_update_elem(pb->map_fd, &map_key,
5554 					  &cpu_buf->fd, 0);
5555 		if (err) {
5556 			err = -errno;
5557 			pr_warning("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
5558 				   cpu, map_key, cpu_buf->fd,
5559 				   libbpf_strerror_r(err, msg, sizeof(msg)));
5560 			goto error;
5561 		}
5562 
5563 		pb->events[i].events = EPOLLIN;
5564 		pb->events[i].data.ptr = cpu_buf;
5565 		if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
5566 			      &pb->events[i]) < 0) {
5567 			err = -errno;
5568 			pr_warning("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
5569 				   cpu, cpu_buf->fd,
5570 				   libbpf_strerror_r(err, msg, sizeof(msg)));
5571 			goto error;
5572 		}
5573 	}
5574 
5575 	return pb;
5576 
5577 error:
5578 	if (pb)
5579 		perf_buffer__free(pb);
5580 	return ERR_PTR(err);
5581 }
5582 
5583 struct perf_sample_raw {
5584 	struct perf_event_header header;
5585 	uint32_t size;
5586 	char data[0];
5587 };
5588 
5589 struct perf_sample_lost {
5590 	struct perf_event_header header;
5591 	uint64_t id;
5592 	uint64_t lost;
5593 	uint64_t sample_id;
5594 };
5595 
5596 static enum bpf_perf_event_ret
perf_buffer__process_record(struct perf_event_header * e,void * ctx)5597 perf_buffer__process_record(struct perf_event_header *e, void *ctx)
5598 {
5599 	struct perf_cpu_buf *cpu_buf = ctx;
5600 	struct perf_buffer *pb = cpu_buf->pb;
5601 	void *data = e;
5602 
5603 	/* user wants full control over parsing perf event */
5604 	if (pb->event_cb)
5605 		return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
5606 
5607 	switch (e->type) {
5608 	case PERF_RECORD_SAMPLE: {
5609 		struct perf_sample_raw *s = data;
5610 
5611 		if (pb->sample_cb)
5612 			pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
5613 		break;
5614 	}
5615 	case PERF_RECORD_LOST: {
5616 		struct perf_sample_lost *s = data;
5617 
5618 		if (pb->lost_cb)
5619 			pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
5620 		break;
5621 	}
5622 	default:
5623 		pr_warning("unknown perf sample type %d\n", e->type);
5624 		return LIBBPF_PERF_EVENT_ERROR;
5625 	}
5626 	return LIBBPF_PERF_EVENT_CONT;
5627 }
5628 
perf_buffer__process_records(struct perf_buffer * pb,struct perf_cpu_buf * cpu_buf)5629 static int perf_buffer__process_records(struct perf_buffer *pb,
5630 					struct perf_cpu_buf *cpu_buf)
5631 {
5632 	enum bpf_perf_event_ret ret;
5633 
5634 	ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
5635 					 pb->page_size, &cpu_buf->buf,
5636 					 &cpu_buf->buf_size,
5637 					 perf_buffer__process_record, cpu_buf);
5638 	if (ret != LIBBPF_PERF_EVENT_CONT)
5639 		return ret;
5640 	return 0;
5641 }
5642 
perf_buffer__poll(struct perf_buffer * pb,int timeout_ms)5643 int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
5644 {
5645 	int i, cnt, err;
5646 
5647 	cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
5648 	for (i = 0; i < cnt; i++) {
5649 		struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
5650 
5651 		err = perf_buffer__process_records(pb, cpu_buf);
5652 		if (err) {
5653 			pr_warning("error while processing records: %d\n", err);
5654 			return err;
5655 		}
5656 	}
5657 	return cnt < 0 ? -errno : cnt;
5658 }
5659 
5660 struct bpf_prog_info_array_desc {
5661 	int	array_offset;	/* e.g. offset of jited_prog_insns */
5662 	int	count_offset;	/* e.g. offset of jited_prog_len */
5663 	int	size_offset;	/* > 0: offset of rec size,
5664 				 * < 0: fix size of -size_offset
5665 				 */
5666 };
5667 
5668 static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
5669 	[BPF_PROG_INFO_JITED_INSNS] = {
5670 		offsetof(struct bpf_prog_info, jited_prog_insns),
5671 		offsetof(struct bpf_prog_info, jited_prog_len),
5672 		-1,
5673 	},
5674 	[BPF_PROG_INFO_XLATED_INSNS] = {
5675 		offsetof(struct bpf_prog_info, xlated_prog_insns),
5676 		offsetof(struct bpf_prog_info, xlated_prog_len),
5677 		-1,
5678 	},
5679 	[BPF_PROG_INFO_MAP_IDS] = {
5680 		offsetof(struct bpf_prog_info, map_ids),
5681 		offsetof(struct bpf_prog_info, nr_map_ids),
5682 		-(int)sizeof(__u32),
5683 	},
5684 	[BPF_PROG_INFO_JITED_KSYMS] = {
5685 		offsetof(struct bpf_prog_info, jited_ksyms),
5686 		offsetof(struct bpf_prog_info, nr_jited_ksyms),
5687 		-(int)sizeof(__u64),
5688 	},
5689 	[BPF_PROG_INFO_JITED_FUNC_LENS] = {
5690 		offsetof(struct bpf_prog_info, jited_func_lens),
5691 		offsetof(struct bpf_prog_info, nr_jited_func_lens),
5692 		-(int)sizeof(__u32),
5693 	},
5694 	[BPF_PROG_INFO_FUNC_INFO] = {
5695 		offsetof(struct bpf_prog_info, func_info),
5696 		offsetof(struct bpf_prog_info, nr_func_info),
5697 		offsetof(struct bpf_prog_info, func_info_rec_size),
5698 	},
5699 	[BPF_PROG_INFO_LINE_INFO] = {
5700 		offsetof(struct bpf_prog_info, line_info),
5701 		offsetof(struct bpf_prog_info, nr_line_info),
5702 		offsetof(struct bpf_prog_info, line_info_rec_size),
5703 	},
5704 	[BPF_PROG_INFO_JITED_LINE_INFO] = {
5705 		offsetof(struct bpf_prog_info, jited_line_info),
5706 		offsetof(struct bpf_prog_info, nr_jited_line_info),
5707 		offsetof(struct bpf_prog_info, jited_line_info_rec_size),
5708 	},
5709 	[BPF_PROG_INFO_PROG_TAGS] = {
5710 		offsetof(struct bpf_prog_info, prog_tags),
5711 		offsetof(struct bpf_prog_info, nr_prog_tags),
5712 		-(int)sizeof(__u8) * BPF_TAG_SIZE,
5713 	},
5714 
5715 };
5716 
bpf_prog_info_read_offset_u32(struct bpf_prog_info * info,int offset)5717 static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info, int offset)
5718 {
5719 	__u32 *array = (__u32 *)info;
5720 
5721 	if (offset >= 0)
5722 		return array[offset / sizeof(__u32)];
5723 	return -(int)offset;
5724 }
5725 
bpf_prog_info_read_offset_u64(struct bpf_prog_info * info,int offset)5726 static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info, int offset)
5727 {
5728 	__u64 *array = (__u64 *)info;
5729 
5730 	if (offset >= 0)
5731 		return array[offset / sizeof(__u64)];
5732 	return -(int)offset;
5733 }
5734 
bpf_prog_info_set_offset_u32(struct bpf_prog_info * info,int offset,__u32 val)5735 static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
5736 					 __u32 val)
5737 {
5738 	__u32 *array = (__u32 *)info;
5739 
5740 	if (offset >= 0)
5741 		array[offset / sizeof(__u32)] = val;
5742 }
5743 
bpf_prog_info_set_offset_u64(struct bpf_prog_info * info,int offset,__u64 val)5744 static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
5745 					 __u64 val)
5746 {
5747 	__u64 *array = (__u64 *)info;
5748 
5749 	if (offset >= 0)
5750 		array[offset / sizeof(__u64)] = val;
5751 }
5752 
5753 struct bpf_prog_info_linear *
bpf_program__get_prog_info_linear(int fd,__u64 arrays)5754 bpf_program__get_prog_info_linear(int fd, __u64 arrays)
5755 {
5756 	struct bpf_prog_info_linear *info_linear;
5757 	struct bpf_prog_info info = {};
5758 	__u32 info_len = sizeof(info);
5759 	__u32 data_len = 0;
5760 	int i, err;
5761 	void *ptr;
5762 
5763 	if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
5764 		return ERR_PTR(-EINVAL);
5765 
5766 	/* step 1: get array dimensions */
5767 	err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
5768 	if (err) {
5769 		pr_debug("can't get prog info: %s", strerror(errno));
5770 		return ERR_PTR(-EFAULT);
5771 	}
5772 
5773 	/* step 2: calculate total size of all arrays */
5774 	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5775 		bool include_array = (arrays & (1UL << i)) > 0;
5776 		struct bpf_prog_info_array_desc *desc;
5777 		__u32 count, size;
5778 
5779 		desc = bpf_prog_info_array_desc + i;
5780 
5781 		/* kernel is too old to support this field */
5782 		if (info_len < desc->array_offset + sizeof(__u32) ||
5783 		    info_len < desc->count_offset + sizeof(__u32) ||
5784 		    (desc->size_offset > 0 && info_len < desc->size_offset))
5785 			include_array = false;
5786 
5787 		if (!include_array) {
5788 			arrays &= ~(1UL << i);	/* clear the bit */
5789 			continue;
5790 		}
5791 
5792 		count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
5793 		size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
5794 
5795 		data_len += count * size;
5796 	}
5797 
5798 	/* step 3: allocate continuous memory */
5799 	data_len = roundup(data_len, sizeof(__u64));
5800 	info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
5801 	if (!info_linear)
5802 		return ERR_PTR(-ENOMEM);
5803 
5804 	/* step 4: fill data to info_linear->info */
5805 	info_linear->arrays = arrays;
5806 	memset(&info_linear->info, 0, sizeof(info));
5807 	ptr = info_linear->data;
5808 
5809 	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5810 		struct bpf_prog_info_array_desc *desc;
5811 		__u32 count, size;
5812 
5813 		if ((arrays & (1UL << i)) == 0)
5814 			continue;
5815 
5816 		desc  = bpf_prog_info_array_desc + i;
5817 		count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
5818 		size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
5819 		bpf_prog_info_set_offset_u32(&info_linear->info,
5820 					     desc->count_offset, count);
5821 		bpf_prog_info_set_offset_u32(&info_linear->info,
5822 					     desc->size_offset, size);
5823 		bpf_prog_info_set_offset_u64(&info_linear->info,
5824 					     desc->array_offset,
5825 					     ptr_to_u64(ptr));
5826 		ptr += count * size;
5827 	}
5828 
5829 	/* step 5: call syscall again to get required arrays */
5830 	err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
5831 	if (err) {
5832 		pr_debug("can't get prog info: %s", strerror(errno));
5833 		free(info_linear);
5834 		return ERR_PTR(-EFAULT);
5835 	}
5836 
5837 	/* step 6: verify the data */
5838 	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5839 		struct bpf_prog_info_array_desc *desc;
5840 		__u32 v1, v2;
5841 
5842 		if ((arrays & (1UL << i)) == 0)
5843 			continue;
5844 
5845 		desc = bpf_prog_info_array_desc + i;
5846 		v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
5847 		v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
5848 						   desc->count_offset);
5849 		if (v1 != v2)
5850 			pr_warning("%s: mismatch in element count\n", __func__);
5851 
5852 		v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
5853 		v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
5854 						   desc->size_offset);
5855 		if (v1 != v2)
5856 			pr_warning("%s: mismatch in rec size\n", __func__);
5857 	}
5858 
5859 	/* step 7: update info_len and data_len */
5860 	info_linear->info_len = sizeof(struct bpf_prog_info);
5861 	info_linear->data_len = data_len;
5862 
5863 	return info_linear;
5864 }
5865 
bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear * info_linear)5866 void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
5867 {
5868 	int i;
5869 
5870 	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5871 		struct bpf_prog_info_array_desc *desc;
5872 		__u64 addr, offs;
5873 
5874 		if ((info_linear->arrays & (1UL << i)) == 0)
5875 			continue;
5876 
5877 		desc = bpf_prog_info_array_desc + i;
5878 		addr = bpf_prog_info_read_offset_u64(&info_linear->info,
5879 						     desc->array_offset);
5880 		offs = addr - ptr_to_u64(info_linear->data);
5881 		bpf_prog_info_set_offset_u64(&info_linear->info,
5882 					     desc->array_offset, offs);
5883 	}
5884 }
5885 
bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear * info_linear)5886 void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
5887 {
5888 	int i;
5889 
5890 	for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
5891 		struct bpf_prog_info_array_desc *desc;
5892 		__u64 addr, offs;
5893 
5894 		if ((info_linear->arrays & (1UL << i)) == 0)
5895 			continue;
5896 
5897 		desc = bpf_prog_info_array_desc + i;
5898 		offs = bpf_prog_info_read_offset_u64(&info_linear->info,
5899 						     desc->array_offset);
5900 		addr = offs + ptr_to_u64(info_linear->data);
5901 		bpf_prog_info_set_offset_u64(&info_linear->info,
5902 					     desc->array_offset, addr);
5903 	}
5904 }
5905 
libbpf_num_possible_cpus(void)5906 int libbpf_num_possible_cpus(void)
5907 {
5908 	static const char *fcpu = "/sys/devices/system/cpu/possible";
5909 	int len = 0, n = 0, il = 0, ir = 0;
5910 	unsigned int start = 0, end = 0;
5911 	int tmp_cpus = 0;
5912 	static int cpus;
5913 	char buf[128];
5914 	int error = 0;
5915 	int fd = -1;
5916 
5917 	tmp_cpus = READ_ONCE(cpus);
5918 	if (tmp_cpus > 0)
5919 		return tmp_cpus;
5920 
5921 	fd = open(fcpu, O_RDONLY);
5922 	if (fd < 0) {
5923 		error = errno;
5924 		pr_warning("Failed to open file %s: %s\n",
5925 			   fcpu, strerror(error));
5926 		return -error;
5927 	}
5928 	len = read(fd, buf, sizeof(buf));
5929 	close(fd);
5930 	if (len <= 0) {
5931 		error = len ? errno : EINVAL;
5932 		pr_warning("Failed to read # of possible cpus from %s: %s\n",
5933 			   fcpu, strerror(error));
5934 		return -error;
5935 	}
5936 	if (len == sizeof(buf)) {
5937 		pr_warning("File %s size overflow\n", fcpu);
5938 		return -EOVERFLOW;
5939 	}
5940 	buf[len] = '\0';
5941 
5942 	for (ir = 0, tmp_cpus = 0; ir <= len; ir++) {
5943 		/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
5944 		if (buf[ir] == ',' || buf[ir] == '\0') {
5945 			buf[ir] = '\0';
5946 			n = sscanf(&buf[il], "%u-%u", &start, &end);
5947 			if (n <= 0) {
5948 				pr_warning("Failed to get # CPUs from %s\n",
5949 					   &buf[il]);
5950 				return -EINVAL;
5951 			} else if (n == 1) {
5952 				end = start;
5953 			}
5954 			tmp_cpus += end - start + 1;
5955 			il = ir + 1;
5956 		}
5957 	}
5958 	if (tmp_cpus <= 0) {
5959 		pr_warning("Invalid #CPUs %d from %s\n", tmp_cpus, fcpu);
5960 		return -EINVAL;
5961 	}
5962 
5963 	WRITE_ONCE(cpus, tmp_cpus);
5964 	return tmp_cpus;
5965 }
5966