1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2 
3 /*
4  * resolve_btfids scans Elf object for .BTF_ids section and resolves
5  * its symbols with BTF ID values.
6  *
7  * Each symbol points to 4 bytes data and is expected to have
8  * following name syntax:
9  *
10  * __BTF_ID__<type>__<symbol>[__<id>]
11  *
12  * type is:
13  *
14  *   func    - lookup BTF_KIND_FUNC symbol with <symbol> name
15  *             and store its ID into the data:
16  *
17  *             __BTF_ID__func__vfs_close__1:
18  *             .zero 4
19  *
20  *   struct  - lookup BTF_KIND_STRUCT symbol with <symbol> name
21  *             and store its ID into the data:
22  *
23  *             __BTF_ID__struct__sk_buff__1:
24  *             .zero 4
25  *
26  *   union   - lookup BTF_KIND_UNION symbol with <symbol> name
27  *             and store its ID into the data:
28  *
29  *             __BTF_ID__union__thread_union__1:
30  *             .zero 4
31  *
32  *   typedef - lookup BTF_KIND_TYPEDEF symbol with <symbol> name
33  *             and store its ID into the data:
34  *
35  *             __BTF_ID__typedef__pid_t__1:
36  *             .zero 4
37  *
38  *   set     - store symbol size into first 4 bytes and sort following
39  *             ID list
40  *
41  *             __BTF_ID__set__list:
42  *             .zero 4
43  *             list:
44  *             __BTF_ID__func__vfs_getattr__3:
45  *             .zero 4
46  *             __BTF_ID__func__vfs_fallocate__4:
47  *             .zero 4
48  */
49 
50 #define  _GNU_SOURCE
51 #include <stdio.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <stdlib.h>
55 #include <libelf.h>
56 #include <gelf.h>
57 #include <sys/stat.h>
58 #include <fcntl.h>
59 #include <errno.h>
60 #include <linux/rbtree.h>
61 #include <linux/zalloc.h>
62 #include <linux/err.h>
63 #include <bpf/btf.h>
64 #include <bpf/libbpf.h>
65 #include <parse-options.h>
66 
67 #define BTF_IDS_SECTION	".BTF_ids"
68 #define BTF_ID		"__BTF_ID__"
69 
70 #define BTF_STRUCT	"struct"
71 #define BTF_UNION	"union"
72 #define BTF_TYPEDEF	"typedef"
73 #define BTF_FUNC	"func"
74 #define BTF_SET		"set"
75 
76 #define ADDR_CNT	100
77 
78 struct btf_id {
79 	struct rb_node	 rb_node;
80 	char		*name;
81 	union {
82 		int	 id;
83 		int	 cnt;
84 	};
85 	int		 addr_cnt;
86 	bool		 is_set;
87 	Elf64_Addr	 addr[ADDR_CNT];
88 };
89 
90 struct object {
91 	const char *path;
92 	const char *btf;
93 	const char *base_btf_path;
94 
95 	struct {
96 		int		 fd;
97 		Elf		*elf;
98 		Elf_Data	*symbols;
99 		Elf_Data	*idlist;
100 		int		 symbols_shndx;
101 		int		 idlist_shndx;
102 		size_t		 strtabidx;
103 		unsigned long	 idlist_addr;
104 	} efile;
105 
106 	struct rb_root	sets;
107 	struct rb_root	structs;
108 	struct rb_root	unions;
109 	struct rb_root	typedefs;
110 	struct rb_root	funcs;
111 
112 	int nr_funcs;
113 	int nr_structs;
114 	int nr_unions;
115 	int nr_typedefs;
116 };
117 
118 static int verbose;
119 
eprintf(int level,int var,const char * fmt,...)120 static int eprintf(int level, int var, const char *fmt, ...)
121 {
122 	va_list args;
123 	int ret = 0;
124 
125 	if (var >= level) {
126 		va_start(args, fmt);
127 		ret = vfprintf(stderr, fmt, args);
128 		va_end(args);
129 	}
130 	return ret;
131 }
132 
133 #ifndef pr_fmt
134 #define pr_fmt(fmt) fmt
135 #endif
136 
137 #define pr_debug(fmt, ...) \
138 	eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__)
139 #define pr_debugN(n, fmt, ...) \
140 	eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__)
141 #define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__)
142 #define pr_err(fmt, ...) \
143 	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
144 #define pr_info(fmt, ...) \
145 	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
146 
is_btf_id(const char * name)147 static bool is_btf_id(const char *name)
148 {
149 	return name && !strncmp(name, BTF_ID, sizeof(BTF_ID) - 1);
150 }
151 
btf_id__find(struct rb_root * root,const char * name)152 static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
153 {
154 	struct rb_node *p = root->rb_node;
155 	struct btf_id *id;
156 	int cmp;
157 
158 	while (p) {
159 		id = rb_entry(p, struct btf_id, rb_node);
160 		cmp = strcmp(id->name, name);
161 		if (cmp < 0)
162 			p = p->rb_left;
163 		else if (cmp > 0)
164 			p = p->rb_right;
165 		else
166 			return id;
167 	}
168 	return NULL;
169 }
170 
171 static struct btf_id *
btf_id__add(struct rb_root * root,char * name,bool unique)172 btf_id__add(struct rb_root *root, char *name, bool unique)
173 {
174 	struct rb_node **p = &root->rb_node;
175 	struct rb_node *parent = NULL;
176 	struct btf_id *id;
177 	int cmp;
178 
179 	while (*p != NULL) {
180 		parent = *p;
181 		id = rb_entry(parent, struct btf_id, rb_node);
182 		cmp = strcmp(id->name, name);
183 		if (cmp < 0)
184 			p = &(*p)->rb_left;
185 		else if (cmp > 0)
186 			p = &(*p)->rb_right;
187 		else
188 			return unique ? NULL : id;
189 	}
190 
191 	id = zalloc(sizeof(*id));
192 	if (id) {
193 		pr_debug("adding symbol %s\n", name);
194 		id->name = name;
195 		rb_link_node(&id->rb_node, parent, p);
196 		rb_insert_color(&id->rb_node, root);
197 	}
198 	return id;
199 }
200 
get_id(const char * prefix_end)201 static char *get_id(const char *prefix_end)
202 {
203 	/*
204 	 * __BTF_ID__func__vfs_truncate__0
205 	 * prefix_end =  ^
206 	 * pos        =    ^
207 	 */
208 	int len = strlen(prefix_end);
209 	int pos = sizeof("__") - 1;
210 	char *p, *id;
211 
212 	if (pos >= len)
213 		return NULL;
214 
215 	id = strdup(prefix_end + pos);
216 	if (id) {
217 		/*
218 		 * __BTF_ID__func__vfs_truncate__0
219 		 * id =            ^
220 		 *
221 		 * cut the unique id part
222 		 */
223 		p = strrchr(id, '_');
224 		p--;
225 		if (*p != '_') {
226 			free(id);
227 			return NULL;
228 		}
229 		*p = '\0';
230 	}
231 	return id;
232 }
233 
add_set(struct object * obj,char * name)234 static struct btf_id *add_set(struct object *obj, char *name)
235 {
236 	/*
237 	 * __BTF_ID__set__name
238 	 * name =    ^
239 	 * id   =         ^
240 	 */
241 	char *id = name + sizeof(BTF_SET "__") - 1;
242 	int len = strlen(name);
243 
244 	if (id >= name + len) {
245 		pr_err("FAILED to parse set name: %s\n", name);
246 		return NULL;
247 	}
248 
249 	return btf_id__add(&obj->sets, id, true);
250 }
251 
add_symbol(struct rb_root * root,char * name,size_t size)252 static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
253 {
254 	char *id;
255 
256 	id = get_id(name + size);
257 	if (!id) {
258 		pr_err("FAILED to parse symbol name: %s\n", name);
259 		return NULL;
260 	}
261 
262 	return btf_id__add(root, id, false);
263 }
264 
265 /* Older libelf.h and glibc elf.h might not yet define the ELF compression types. */
266 #ifndef SHF_COMPRESSED
267 #define SHF_COMPRESSED (1 << 11) /* Section with compressed data. */
268 #endif
269 
270 /*
271  * The data of compressed section should be aligned to 4
272  * (for 32bit) or 8 (for 64 bit) bytes. The binutils ld
273  * sets sh_addralign to 1, which makes libelf fail with
274  * misaligned section error during the update:
275  *    FAILED elf_update(WRITE): invalid section alignment
276  *
277  * While waiting for ld fix, we fix the compressed sections
278  * sh_addralign value manualy.
279  */
compressed_section_fix(Elf * elf,Elf_Scn * scn,GElf_Shdr * sh)280 static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh)
281 {
282 	int expected = gelf_getclass(elf) == ELFCLASS32 ? 4 : 8;
283 
284 	if (!(sh->sh_flags & SHF_COMPRESSED))
285 		return 0;
286 
287 	if (sh->sh_addralign == expected)
288 		return 0;
289 
290 	pr_debug2(" - fixing wrong alignment sh_addralign %u, expected %u\n",
291 		  sh->sh_addralign, expected);
292 
293 	sh->sh_addralign = expected;
294 
295 	if (gelf_update_shdr(scn, sh) == 0) {
296 		pr_err("FAILED cannot update section header: %s\n",
297 			elf_errmsg(-1));
298 		return -1;
299 	}
300 	return 0;
301 }
302 
elf_collect(struct object * obj)303 static int elf_collect(struct object *obj)
304 {
305 	Elf_Scn *scn = NULL;
306 	size_t shdrstrndx;
307 	int idx = 0;
308 	Elf *elf;
309 	int fd;
310 
311 	fd = open(obj->path, O_RDWR, 0666);
312 	if (fd == -1) {
313 		pr_err("FAILED cannot open %s: %s\n",
314 			obj->path, strerror(errno));
315 		return -1;
316 	}
317 
318 	elf_version(EV_CURRENT);
319 
320 	elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL);
321 	if (!elf) {
322 		close(fd);
323 		pr_err("FAILED cannot create ELF descriptor: %s\n",
324 			elf_errmsg(-1));
325 		return -1;
326 	}
327 
328 	obj->efile.fd  = fd;
329 	obj->efile.elf = elf;
330 
331 	elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT);
332 
333 	if (elf_getshdrstrndx(elf, &shdrstrndx) != 0) {
334 		pr_err("FAILED cannot get shdr str ndx\n");
335 		return -1;
336 	}
337 
338 	/*
339 	 * Scan all the elf sections and look for save data
340 	 * from .BTF_ids section and symbols.
341 	 */
342 	while ((scn = elf_nextscn(elf, scn)) != NULL) {
343 		Elf_Data *data;
344 		GElf_Shdr sh;
345 		char *name;
346 
347 		idx++;
348 		if (gelf_getshdr(scn, &sh) != &sh) {
349 			pr_err("FAILED get section(%d) header\n", idx);
350 			return -1;
351 		}
352 
353 		name = elf_strptr(elf, shdrstrndx, sh.sh_name);
354 		if (!name) {
355 			pr_err("FAILED get section(%d) name\n", idx);
356 			return -1;
357 		}
358 
359 		data = elf_getdata(scn, 0);
360 		if (!data) {
361 			pr_err("FAILED to get section(%d) data from %s\n",
362 				idx, name);
363 			return -1;
364 		}
365 
366 		pr_debug2("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
367 			  idx, name, (unsigned long) data->d_size,
368 			  (int) sh.sh_link, (unsigned long) sh.sh_flags,
369 			  (int) sh.sh_type);
370 
371 		if (sh.sh_type == SHT_SYMTAB) {
372 			obj->efile.symbols       = data;
373 			obj->efile.symbols_shndx = idx;
374 			obj->efile.strtabidx     = sh.sh_link;
375 		} else if (!strcmp(name, BTF_IDS_SECTION)) {
376 			obj->efile.idlist       = data;
377 			obj->efile.idlist_shndx = idx;
378 			obj->efile.idlist_addr  = sh.sh_addr;
379 		}
380 
381 		if (compressed_section_fix(elf, scn, &sh))
382 			return -1;
383 	}
384 
385 	return 0;
386 }
387 
symbols_collect(struct object * obj)388 static int symbols_collect(struct object *obj)
389 {
390 	Elf_Scn *scn = NULL;
391 	int n, i;
392 	GElf_Shdr sh;
393 	char *name;
394 
395 	scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
396 	if (!scn)
397 		return -1;
398 
399 	if (gelf_getshdr(scn, &sh) != &sh)
400 		return -1;
401 
402 	n = sh.sh_size / sh.sh_entsize;
403 
404 	/*
405 	 * Scan symbols and look for the ones starting with
406 	 * __BTF_ID__* over .BTF_ids section.
407 	 */
408 	for (i = 0; i < n; i++) {
409 		char *prefix;
410 		struct btf_id *id;
411 		GElf_Sym sym;
412 
413 		if (!gelf_getsym(obj->efile.symbols, i, &sym))
414 			return -1;
415 
416 		if (sym.st_shndx != obj->efile.idlist_shndx)
417 			continue;
418 
419 		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
420 				  sym.st_name);
421 
422 		if (!is_btf_id(name))
423 			continue;
424 
425 		/*
426 		 * __BTF_ID__TYPE__vfs_truncate__0
427 		 * prefix =  ^
428 		 */
429 		prefix = name + sizeof(BTF_ID) - 1;
430 
431 		/* struct */
432 		if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) {
433 			obj->nr_structs++;
434 			id = add_symbol(&obj->structs, prefix, sizeof(BTF_STRUCT) - 1);
435 		/* union  */
436 		} else if (!strncmp(prefix, BTF_UNION, sizeof(BTF_UNION) - 1)) {
437 			obj->nr_unions++;
438 			id = add_symbol(&obj->unions, prefix, sizeof(BTF_UNION) - 1);
439 		/* typedef */
440 		} else if (!strncmp(prefix, BTF_TYPEDEF, sizeof(BTF_TYPEDEF) - 1)) {
441 			obj->nr_typedefs++;
442 			id = add_symbol(&obj->typedefs, prefix, sizeof(BTF_TYPEDEF) - 1);
443 		/* func */
444 		} else if (!strncmp(prefix, BTF_FUNC, sizeof(BTF_FUNC) - 1)) {
445 			obj->nr_funcs++;
446 			id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);
447 		/* set */
448 		} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {
449 			id = add_set(obj, prefix);
450 			/*
451 			 * SET objects store list's count, which is encoded
452 			 * in symbol's size, together with 'cnt' field hence
453 			 * that - 1.
454 			 */
455 			if (id) {
456 				id->cnt = sym.st_size / sizeof(int) - 1;
457 				id->is_set = true;
458 			}
459 		} else {
460 			pr_err("FAILED unsupported prefix %s\n", prefix);
461 			return -1;
462 		}
463 
464 		if (!id)
465 			return -ENOMEM;
466 
467 		if (id->addr_cnt >= ADDR_CNT) {
468 			pr_err("FAILED symbol %s crossed the number of allowed lists\n",
469 				id->name);
470 			return -1;
471 		}
472 		id->addr[id->addr_cnt++] = sym.st_value;
473 	}
474 
475 	return 0;
476 }
477 
symbols_resolve(struct object * obj)478 static int symbols_resolve(struct object *obj)
479 {
480 	int nr_typedefs = obj->nr_typedefs;
481 	int nr_structs  = obj->nr_structs;
482 	int nr_unions   = obj->nr_unions;
483 	int nr_funcs    = obj->nr_funcs;
484 	struct btf *base_btf = NULL;
485 	int err, type_id;
486 	struct btf *btf;
487 	__u32 nr_types;
488 
489 	if (obj->base_btf_path) {
490 		base_btf = btf__parse(obj->base_btf_path, NULL);
491 		err = libbpf_get_error(base_btf);
492 		if (err) {
493 			pr_err("FAILED: load base BTF from %s: %s\n",
494 			       obj->base_btf_path, strerror(-err));
495 			return -1;
496 		}
497 	}
498 
499 	btf = btf__parse_split(obj->btf ?: obj->path, base_btf);
500 	err = libbpf_get_error(btf);
501 	if (err) {
502 		pr_err("FAILED: load BTF from %s: %s\n",
503 			obj->btf ?: obj->path, strerror(-err));
504 		goto out;
505 	}
506 
507 	err = -1;
508 	nr_types = btf__type_cnt(btf);
509 
510 	/*
511 	 * Iterate all the BTF types and search for collected symbol IDs.
512 	 */
513 	for (type_id = 1; type_id < nr_types; type_id++) {
514 		const struct btf_type *type;
515 		struct rb_root *root;
516 		struct btf_id *id;
517 		const char *str;
518 		int *nr;
519 
520 		type = btf__type_by_id(btf, type_id);
521 		if (!type) {
522 			pr_err("FAILED: malformed BTF, can't resolve type for ID %d\n",
523 				type_id);
524 			goto out;
525 		}
526 
527 		if (btf_is_func(type) && nr_funcs) {
528 			nr   = &nr_funcs;
529 			root = &obj->funcs;
530 		} else if (btf_is_struct(type) && nr_structs) {
531 			nr   = &nr_structs;
532 			root = &obj->structs;
533 		} else if (btf_is_union(type) && nr_unions) {
534 			nr   = &nr_unions;
535 			root = &obj->unions;
536 		} else if (btf_is_typedef(type) && nr_typedefs) {
537 			nr   = &nr_typedefs;
538 			root = &obj->typedefs;
539 		} else
540 			continue;
541 
542 		str = btf__name_by_offset(btf, type->name_off);
543 		if (!str) {
544 			pr_err("FAILED: malformed BTF, can't resolve name for ID %d\n",
545 				type_id);
546 			goto out;
547 		}
548 
549 		id = btf_id__find(root, str);
550 		if (id) {
551 			if (id->id) {
552 				pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n",
553 					str, id->id, type_id, id->id);
554 			} else {
555 				id->id = type_id;
556 				(*nr)--;
557 			}
558 		}
559 	}
560 
561 	err = 0;
562 out:
563 	btf__free(base_btf);
564 	btf__free(btf);
565 	return err;
566 }
567 
id_patch(struct object * obj,struct btf_id * id)568 static int id_patch(struct object *obj, struct btf_id *id)
569 {
570 	Elf_Data *data = obj->efile.idlist;
571 	int *ptr = data->d_buf;
572 	int i;
573 
574 	if (!id->id && !id->is_set)
575 		pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
576 
577 	for (i = 0; i < id->addr_cnt; i++) {
578 		unsigned long addr = id->addr[i];
579 		unsigned long idx = addr - obj->efile.idlist_addr;
580 
581 		pr_debug("patching addr %5lu: ID %7d [%s]\n",
582 			 idx, id->id, id->name);
583 
584 		if (idx >= data->d_size) {
585 			pr_err("FAILED patching index %lu out of bounds %lu\n",
586 				idx, data->d_size);
587 			return -1;
588 		}
589 
590 		idx = idx / sizeof(int);
591 		ptr[idx] = id->id;
592 	}
593 
594 	return 0;
595 }
596 
__symbols_patch(struct object * obj,struct rb_root * root)597 static int __symbols_patch(struct object *obj, struct rb_root *root)
598 {
599 	struct rb_node *next;
600 	struct btf_id *id;
601 
602 	next = rb_first(root);
603 	while (next) {
604 		id = rb_entry(next, struct btf_id, rb_node);
605 
606 		if (id_patch(obj, id))
607 			return -1;
608 
609 		next = rb_next(next);
610 	}
611 	return 0;
612 }
613 
cmp_id(const void * pa,const void * pb)614 static int cmp_id(const void *pa, const void *pb)
615 {
616 	const int *a = pa, *b = pb;
617 
618 	return *a - *b;
619 }
620 
sets_patch(struct object * obj)621 static int sets_patch(struct object *obj)
622 {
623 	Elf_Data *data = obj->efile.idlist;
624 	int *ptr = data->d_buf;
625 	struct rb_node *next;
626 
627 	next = rb_first(&obj->sets);
628 	while (next) {
629 		unsigned long addr, idx;
630 		struct btf_id *id;
631 		int *base;
632 		int cnt;
633 
634 		id   = rb_entry(next, struct btf_id, rb_node);
635 		addr = id->addr[0];
636 		idx  = addr - obj->efile.idlist_addr;
637 
638 		/* sets are unique */
639 		if (id->addr_cnt != 1) {
640 			pr_err("FAILED malformed data for set '%s'\n",
641 				id->name);
642 			return -1;
643 		}
644 
645 		idx = idx / sizeof(int);
646 		base = &ptr[idx] + 1;
647 		cnt = ptr[idx];
648 
649 		pr_debug("sorting  addr %5lu: cnt %6d [%s]\n",
650 			 (idx + 1) * sizeof(int), cnt, id->name);
651 
652 		qsort(base, cnt, sizeof(int), cmp_id);
653 
654 		next = rb_next(next);
655 	}
656 	return 0;
657 }
658 
symbols_patch(struct object * obj)659 static int symbols_patch(struct object *obj)
660 {
661 	int err;
662 
663 	if (__symbols_patch(obj, &obj->structs)  ||
664 	    __symbols_patch(obj, &obj->unions)   ||
665 	    __symbols_patch(obj, &obj->typedefs) ||
666 	    __symbols_patch(obj, &obj->funcs)    ||
667 	    __symbols_patch(obj, &obj->sets))
668 		return -1;
669 
670 	if (sets_patch(obj))
671 		return -1;
672 
673 	/* Set type to ensure endian translation occurs. */
674 	obj->efile.idlist->d_type = ELF_T_WORD;
675 
676 	elf_flagdata(obj->efile.idlist, ELF_C_SET, ELF_F_DIRTY);
677 
678 	err = elf_update(obj->efile.elf, ELF_C_WRITE);
679 	if (err < 0) {
680 		pr_err("FAILED elf_update(WRITE): %s\n",
681 			elf_errmsg(-1));
682 	}
683 
684 	pr_debug("update %s for %s\n",
685 		 err >= 0 ? "ok" : "failed", obj->path);
686 	return err < 0 ? -1 : 0;
687 }
688 
689 static const char * const resolve_btfids_usage[] = {
690 	"resolve_btfids [<options>] <ELF object>",
691 	NULL
692 };
693 
main(int argc,const char ** argv)694 int main(int argc, const char **argv)
695 {
696 	struct object obj = {
697 		.efile = {
698 			.idlist_shndx  = -1,
699 			.symbols_shndx = -1,
700 		},
701 		.structs  = RB_ROOT,
702 		.unions   = RB_ROOT,
703 		.typedefs = RB_ROOT,
704 		.funcs    = RB_ROOT,
705 		.sets     = RB_ROOT,
706 	};
707 	struct option btfid_options[] = {
708 		OPT_INCR('v', "verbose", &verbose,
709 			 "be more verbose (show errors, etc)"),
710 		OPT_STRING(0, "btf", &obj.btf, "BTF data",
711 			   "BTF data"),
712 		OPT_STRING('b', "btf_base", &obj.base_btf_path, "file",
713 			   "path of file providing base BTF"),
714 		OPT_END()
715 	};
716 	int err = -1;
717 
718 	argc = parse_options(argc, argv, btfid_options, resolve_btfids_usage,
719 			     PARSE_OPT_STOP_AT_NON_OPTION);
720 	if (argc != 1)
721 		usage_with_options(resolve_btfids_usage, btfid_options);
722 
723 	obj.path = argv[0];
724 
725 	if (elf_collect(&obj))
726 		goto out;
727 
728 	/*
729 	 * We did not find .BTF_ids section or symbols section,
730 	 * nothing to do..
731 	 */
732 	if (obj.efile.idlist_shndx == -1 ||
733 	    obj.efile.symbols_shndx == -1) {
734 		pr_debug("Cannot find .BTF_ids or symbols sections, nothing to do\n");
735 		err = 0;
736 		goto out;
737 	}
738 
739 	if (symbols_collect(&obj))
740 		goto out;
741 
742 	if (symbols_resolve(&obj))
743 		goto out;
744 
745 	if (symbols_patch(&obj))
746 		goto out;
747 
748 	err = 0;
749 out:
750 	if (obj.efile.elf) {
751 		elf_end(obj.efile.elf);
752 		close(obj.efile.fd);
753 	}
754 	return err;
755 }
756