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  *   set8    - store symbol size into first 4 bytes and sort following
50  *             ID list
51  *
52  *             __BTF_ID__set8__list:
53  *             .zero 8
54  *             list:
55  *             __BTF_ID__func__vfs_getattr__3:
56  *             .zero 4
57  *	       .word (1 << 0) | (1 << 2)
58  *             __BTF_ID__func__vfs_fallocate__5:
59  *             .zero 4
60  *	       .word (1 << 3) | (1 << 1) | (1 << 2)
61  */
62 
63 #define  _GNU_SOURCE
64 #include <stdio.h>
65 #include <string.h>
66 #include <unistd.h>
67 #include <stdlib.h>
68 #include <libelf.h>
69 #include <gelf.h>
70 #include <sys/stat.h>
71 #include <fcntl.h>
72 #include <errno.h>
73 #include <linux/rbtree.h>
74 #include <linux/zalloc.h>
75 #include <linux/err.h>
76 #include <bpf/btf.h>
77 #include <bpf/libbpf.h>
78 #include <subcmd/parse-options.h>
79 
80 #define BTF_IDS_SECTION	".BTF_ids"
81 #define BTF_ID		"__BTF_ID__"
82 
83 #define BTF_STRUCT	"struct"
84 #define BTF_UNION	"union"
85 #define BTF_TYPEDEF	"typedef"
86 #define BTF_FUNC	"func"
87 #define BTF_SET		"set"
88 #define BTF_SET8	"set8"
89 
90 #define ADDR_CNT	100
91 
92 struct btf_id {
93 	struct rb_node	 rb_node;
94 	char		*name;
95 	union {
96 		int	 id;
97 		int	 cnt;
98 	};
99 	int		 addr_cnt;
100 	bool		 is_set;
101 	bool		 is_set8;
102 	Elf64_Addr	 addr[ADDR_CNT];
103 };
104 
105 struct object {
106 	const char *path;
107 	const char *btf;
108 	const char *base_btf_path;
109 
110 	struct {
111 		int		 fd;
112 		Elf		*elf;
113 		Elf_Data	*symbols;
114 		Elf_Data	*idlist;
115 		int		 symbols_shndx;
116 		int		 idlist_shndx;
117 		size_t		 strtabidx;
118 		unsigned long	 idlist_addr;
119 	} efile;
120 
121 	struct rb_root	sets;
122 	struct rb_root	structs;
123 	struct rb_root	unions;
124 	struct rb_root	typedefs;
125 	struct rb_root	funcs;
126 
127 	int nr_funcs;
128 	int nr_structs;
129 	int nr_unions;
130 	int nr_typedefs;
131 };
132 
133 static int verbose;
134 
eprintf(int level,int var,const char * fmt,...)135 static int eprintf(int level, int var, const char *fmt, ...)
136 {
137 	va_list args;
138 	int ret = 0;
139 
140 	if (var >= level) {
141 		va_start(args, fmt);
142 		ret = vfprintf(stderr, fmt, args);
143 		va_end(args);
144 	}
145 	return ret;
146 }
147 
148 #ifndef pr_fmt
149 #define pr_fmt(fmt) fmt
150 #endif
151 
152 #define pr_debug(fmt, ...) \
153 	eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__)
154 #define pr_debugN(n, fmt, ...) \
155 	eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__)
156 #define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__)
157 #define pr_err(fmt, ...) \
158 	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
159 #define pr_info(fmt, ...) \
160 	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
161 
is_btf_id(const char * name)162 static bool is_btf_id(const char *name)
163 {
164 	return name && !strncmp(name, BTF_ID, sizeof(BTF_ID) - 1);
165 }
166 
btf_id__find(struct rb_root * root,const char * name)167 static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
168 {
169 	struct rb_node *p = root->rb_node;
170 	struct btf_id *id;
171 	int cmp;
172 
173 	while (p) {
174 		id = rb_entry(p, struct btf_id, rb_node);
175 		cmp = strcmp(id->name, name);
176 		if (cmp < 0)
177 			p = p->rb_left;
178 		else if (cmp > 0)
179 			p = p->rb_right;
180 		else
181 			return id;
182 	}
183 	return NULL;
184 }
185 
186 static struct btf_id *
btf_id__add(struct rb_root * root,char * name,bool unique)187 btf_id__add(struct rb_root *root, char *name, bool unique)
188 {
189 	struct rb_node **p = &root->rb_node;
190 	struct rb_node *parent = NULL;
191 	struct btf_id *id;
192 	int cmp;
193 
194 	while (*p != NULL) {
195 		parent = *p;
196 		id = rb_entry(parent, struct btf_id, rb_node);
197 		cmp = strcmp(id->name, name);
198 		if (cmp < 0)
199 			p = &(*p)->rb_left;
200 		else if (cmp > 0)
201 			p = &(*p)->rb_right;
202 		else
203 			return unique ? NULL : id;
204 	}
205 
206 	id = zalloc(sizeof(*id));
207 	if (id) {
208 		pr_debug("adding symbol %s\n", name);
209 		id->name = name;
210 		rb_link_node(&id->rb_node, parent, p);
211 		rb_insert_color(&id->rb_node, root);
212 	}
213 	return id;
214 }
215 
get_id(const char * prefix_end)216 static char *get_id(const char *prefix_end)
217 {
218 	/*
219 	 * __BTF_ID__func__vfs_truncate__0
220 	 * prefix_end =  ^
221 	 * pos        =    ^
222 	 */
223 	int len = strlen(prefix_end);
224 	int pos = sizeof("__") - 1;
225 	char *p, *id;
226 
227 	if (pos >= len)
228 		return NULL;
229 
230 	id = strdup(prefix_end + pos);
231 	if (id) {
232 		/*
233 		 * __BTF_ID__func__vfs_truncate__0
234 		 * id =            ^
235 		 *
236 		 * cut the unique id part
237 		 */
238 		p = strrchr(id, '_');
239 		p--;
240 		if (*p != '_') {
241 			free(id);
242 			return NULL;
243 		}
244 		*p = '\0';
245 	}
246 	return id;
247 }
248 
add_set(struct object * obj,char * name,bool is_set8)249 static struct btf_id *add_set(struct object *obj, char *name, bool is_set8)
250 {
251 	/*
252 	 * __BTF_ID__set__name
253 	 * name =    ^
254 	 * id   =         ^
255 	 */
256 	char *id = name + (is_set8 ? sizeof(BTF_SET8 "__") : sizeof(BTF_SET "__")) - 1;
257 	int len = strlen(name);
258 
259 	if (id >= name + len) {
260 		pr_err("FAILED to parse set name: %s\n", name);
261 		return NULL;
262 	}
263 
264 	return btf_id__add(&obj->sets, id, true);
265 }
266 
add_symbol(struct rb_root * root,char * name,size_t size)267 static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
268 {
269 	char *id;
270 
271 	id = get_id(name + size);
272 	if (!id) {
273 		pr_err("FAILED to parse symbol name: %s\n", name);
274 		return NULL;
275 	}
276 
277 	return btf_id__add(root, id, false);
278 }
279 
280 /* Older libelf.h and glibc elf.h might not yet define the ELF compression types. */
281 #ifndef SHF_COMPRESSED
282 #define SHF_COMPRESSED (1 << 11) /* Section with compressed data. */
283 #endif
284 
285 /*
286  * The data of compressed section should be aligned to 4
287  * (for 32bit) or 8 (for 64 bit) bytes. The binutils ld
288  * sets sh_addralign to 1, which makes libelf fail with
289  * misaligned section error during the update:
290  *    FAILED elf_update(WRITE): invalid section alignment
291  *
292  * While waiting for ld fix, we fix the compressed sections
293  * sh_addralign value manualy.
294  */
compressed_section_fix(Elf * elf,Elf_Scn * scn,GElf_Shdr * sh)295 static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh)
296 {
297 	int expected = gelf_getclass(elf) == ELFCLASS32 ? 4 : 8;
298 
299 	if (!(sh->sh_flags & SHF_COMPRESSED))
300 		return 0;
301 
302 	if (sh->sh_addralign == expected)
303 		return 0;
304 
305 	pr_debug2(" - fixing wrong alignment sh_addralign %u, expected %u\n",
306 		  sh->sh_addralign, expected);
307 
308 	sh->sh_addralign = expected;
309 
310 	if (gelf_update_shdr(scn, sh) == 0) {
311 		pr_err("FAILED cannot update section header: %s\n",
312 			elf_errmsg(-1));
313 		return -1;
314 	}
315 	return 0;
316 }
317 
elf_collect(struct object * obj)318 static int elf_collect(struct object *obj)
319 {
320 	Elf_Scn *scn = NULL;
321 	size_t shdrstrndx;
322 	int idx = 0;
323 	Elf *elf;
324 	int fd;
325 
326 	fd = open(obj->path, O_RDWR, 0666);
327 	if (fd == -1) {
328 		pr_err("FAILED cannot open %s: %s\n",
329 			obj->path, strerror(errno));
330 		return -1;
331 	}
332 
333 	elf_version(EV_CURRENT);
334 
335 	elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL);
336 	if (!elf) {
337 		close(fd);
338 		pr_err("FAILED cannot create ELF descriptor: %s\n",
339 			elf_errmsg(-1));
340 		return -1;
341 	}
342 
343 	obj->efile.fd  = fd;
344 	obj->efile.elf = elf;
345 
346 	elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT);
347 
348 	if (elf_getshdrstrndx(elf, &shdrstrndx) != 0) {
349 		pr_err("FAILED cannot get shdr str ndx\n");
350 		return -1;
351 	}
352 
353 	/*
354 	 * Scan all the elf sections and look for save data
355 	 * from .BTF_ids section and symbols.
356 	 */
357 	while ((scn = elf_nextscn(elf, scn)) != NULL) {
358 		Elf_Data *data;
359 		GElf_Shdr sh;
360 		char *name;
361 
362 		idx++;
363 		if (gelf_getshdr(scn, &sh) != &sh) {
364 			pr_err("FAILED get section(%d) header\n", idx);
365 			return -1;
366 		}
367 
368 		name = elf_strptr(elf, shdrstrndx, sh.sh_name);
369 		if (!name) {
370 			pr_err("FAILED get section(%d) name\n", idx);
371 			return -1;
372 		}
373 
374 		data = elf_getdata(scn, 0);
375 		if (!data) {
376 			pr_err("FAILED to get section(%d) data from %s\n",
377 				idx, name);
378 			return -1;
379 		}
380 
381 		pr_debug2("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
382 			  idx, name, (unsigned long) data->d_size,
383 			  (int) sh.sh_link, (unsigned long) sh.sh_flags,
384 			  (int) sh.sh_type);
385 
386 		if (sh.sh_type == SHT_SYMTAB) {
387 			obj->efile.symbols       = data;
388 			obj->efile.symbols_shndx = idx;
389 			obj->efile.strtabidx     = sh.sh_link;
390 		} else if (!strcmp(name, BTF_IDS_SECTION)) {
391 			obj->efile.idlist       = data;
392 			obj->efile.idlist_shndx = idx;
393 			obj->efile.idlist_addr  = sh.sh_addr;
394 		}
395 
396 		if (compressed_section_fix(elf, scn, &sh))
397 			return -1;
398 	}
399 
400 	return 0;
401 }
402 
symbols_collect(struct object * obj)403 static int symbols_collect(struct object *obj)
404 {
405 	Elf_Scn *scn = NULL;
406 	int n, i;
407 	GElf_Shdr sh;
408 	char *name;
409 
410 	scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
411 	if (!scn)
412 		return -1;
413 
414 	if (gelf_getshdr(scn, &sh) != &sh)
415 		return -1;
416 
417 	n = sh.sh_size / sh.sh_entsize;
418 
419 	/*
420 	 * Scan symbols and look for the ones starting with
421 	 * __BTF_ID__* over .BTF_ids section.
422 	 */
423 	for (i = 0; i < n; i++) {
424 		char *prefix;
425 		struct btf_id *id;
426 		GElf_Sym sym;
427 
428 		if (!gelf_getsym(obj->efile.symbols, i, &sym))
429 			return -1;
430 
431 		if (sym.st_shndx != obj->efile.idlist_shndx)
432 			continue;
433 
434 		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
435 				  sym.st_name);
436 
437 		if (!is_btf_id(name))
438 			continue;
439 
440 		/*
441 		 * __BTF_ID__TYPE__vfs_truncate__0
442 		 * prefix =  ^
443 		 */
444 		prefix = name + sizeof(BTF_ID) - 1;
445 
446 		/* struct */
447 		if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) {
448 			obj->nr_structs++;
449 			id = add_symbol(&obj->structs, prefix, sizeof(BTF_STRUCT) - 1);
450 		/* union  */
451 		} else if (!strncmp(prefix, BTF_UNION, sizeof(BTF_UNION) - 1)) {
452 			obj->nr_unions++;
453 			id = add_symbol(&obj->unions, prefix, sizeof(BTF_UNION) - 1);
454 		/* typedef */
455 		} else if (!strncmp(prefix, BTF_TYPEDEF, sizeof(BTF_TYPEDEF) - 1)) {
456 			obj->nr_typedefs++;
457 			id = add_symbol(&obj->typedefs, prefix, sizeof(BTF_TYPEDEF) - 1);
458 		/* func */
459 		} else if (!strncmp(prefix, BTF_FUNC, sizeof(BTF_FUNC) - 1)) {
460 			obj->nr_funcs++;
461 			id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);
462 		/* set8 */
463 		} else if (!strncmp(prefix, BTF_SET8, sizeof(BTF_SET8) - 1)) {
464 			id = add_set(obj, prefix, true);
465 			/*
466 			 * SET8 objects store list's count, which is encoded
467 			 * in symbol's size, together with 'cnt' field hence
468 			 * that - 1.
469 			 */
470 			if (id) {
471 				id->cnt = sym.st_size / sizeof(uint64_t) - 1;
472 				id->is_set8 = true;
473 			}
474 		/* set */
475 		} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {
476 			id = add_set(obj, prefix, false);
477 			/*
478 			 * SET objects store list's count, which is encoded
479 			 * in symbol's size, together with 'cnt' field hence
480 			 * that - 1.
481 			 */
482 			if (id) {
483 				id->cnt = sym.st_size / sizeof(int) - 1;
484 				id->is_set = true;
485 			}
486 		} else {
487 			pr_err("FAILED unsupported prefix %s\n", prefix);
488 			return -1;
489 		}
490 
491 		if (!id)
492 			return -ENOMEM;
493 
494 		if (id->addr_cnt >= ADDR_CNT) {
495 			pr_err("FAILED symbol %s crossed the number of allowed lists\n",
496 				id->name);
497 			return -1;
498 		}
499 		id->addr[id->addr_cnt++] = sym.st_value;
500 	}
501 
502 	return 0;
503 }
504 
symbols_resolve(struct object * obj)505 static int symbols_resolve(struct object *obj)
506 {
507 	int nr_typedefs = obj->nr_typedefs;
508 	int nr_structs  = obj->nr_structs;
509 	int nr_unions   = obj->nr_unions;
510 	int nr_funcs    = obj->nr_funcs;
511 	struct btf *base_btf = NULL;
512 	int err, type_id;
513 	struct btf *btf;
514 	__u32 nr_types;
515 
516 	if (obj->base_btf_path) {
517 		base_btf = btf__parse(obj->base_btf_path, NULL);
518 		err = libbpf_get_error(base_btf);
519 		if (err) {
520 			pr_err("FAILED: load base BTF from %s: %s\n",
521 			       obj->base_btf_path, strerror(-err));
522 			return -1;
523 		}
524 	}
525 
526 	btf = btf__parse_split(obj->btf ?: obj->path, base_btf);
527 	err = libbpf_get_error(btf);
528 	if (err) {
529 		pr_err("FAILED: load BTF from %s: %s\n",
530 			obj->btf ?: obj->path, strerror(-err));
531 		goto out;
532 	}
533 
534 	err = -1;
535 	nr_types = btf__type_cnt(btf);
536 
537 	/*
538 	 * Iterate all the BTF types and search for collected symbol IDs.
539 	 */
540 	for (type_id = 1; type_id < nr_types; type_id++) {
541 		const struct btf_type *type;
542 		struct rb_root *root;
543 		struct btf_id *id;
544 		const char *str;
545 		int *nr;
546 
547 		type = btf__type_by_id(btf, type_id);
548 		if (!type) {
549 			pr_err("FAILED: malformed BTF, can't resolve type for ID %d\n",
550 				type_id);
551 			goto out;
552 		}
553 
554 		if (btf_is_func(type) && nr_funcs) {
555 			nr   = &nr_funcs;
556 			root = &obj->funcs;
557 		} else if (btf_is_struct(type) && nr_structs) {
558 			nr   = &nr_structs;
559 			root = &obj->structs;
560 		} else if (btf_is_union(type) && nr_unions) {
561 			nr   = &nr_unions;
562 			root = &obj->unions;
563 		} else if (btf_is_typedef(type) && nr_typedefs) {
564 			nr   = &nr_typedefs;
565 			root = &obj->typedefs;
566 		} else
567 			continue;
568 
569 		str = btf__name_by_offset(btf, type->name_off);
570 		if (!str) {
571 			pr_err("FAILED: malformed BTF, can't resolve name for ID %d\n",
572 				type_id);
573 			goto out;
574 		}
575 
576 		id = btf_id__find(root, str);
577 		if (id) {
578 			if (id->id) {
579 				pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n",
580 					str, id->id, type_id, id->id);
581 			} else {
582 				id->id = type_id;
583 				(*nr)--;
584 			}
585 		}
586 	}
587 
588 	err = 0;
589 out:
590 	btf__free(base_btf);
591 	btf__free(btf);
592 	return err;
593 }
594 
id_patch(struct object * obj,struct btf_id * id)595 static int id_patch(struct object *obj, struct btf_id *id)
596 {
597 	Elf_Data *data = obj->efile.idlist;
598 	int *ptr = data->d_buf;
599 	int i;
600 
601 	/* For set, set8, id->id may be 0 */
602 	if (!id->id && !id->is_set && !id->is_set8)
603 		pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
604 
605 	for (i = 0; i < id->addr_cnt; i++) {
606 		unsigned long addr = id->addr[i];
607 		unsigned long idx = addr - obj->efile.idlist_addr;
608 
609 		pr_debug("patching addr %5lu: ID %7d [%s]\n",
610 			 idx, id->id, id->name);
611 
612 		if (idx >= data->d_size) {
613 			pr_err("FAILED patching index %lu out of bounds %lu\n",
614 				idx, data->d_size);
615 			return -1;
616 		}
617 
618 		idx = idx / sizeof(int);
619 		ptr[idx] = id->id;
620 	}
621 
622 	return 0;
623 }
624 
__symbols_patch(struct object * obj,struct rb_root * root)625 static int __symbols_patch(struct object *obj, struct rb_root *root)
626 {
627 	struct rb_node *next;
628 	struct btf_id *id;
629 
630 	next = rb_first(root);
631 	while (next) {
632 		id = rb_entry(next, struct btf_id, rb_node);
633 
634 		if (id_patch(obj, id))
635 			return -1;
636 
637 		next = rb_next(next);
638 	}
639 	return 0;
640 }
641 
cmp_id(const void * pa,const void * pb)642 static int cmp_id(const void *pa, const void *pb)
643 {
644 	const int *a = pa, *b = pb;
645 
646 	return *a - *b;
647 }
648 
sets_patch(struct object * obj)649 static int sets_patch(struct object *obj)
650 {
651 	Elf_Data *data = obj->efile.idlist;
652 	int *ptr = data->d_buf;
653 	struct rb_node *next;
654 
655 	next = rb_first(&obj->sets);
656 	while (next) {
657 		unsigned long addr, idx;
658 		struct btf_id *id;
659 		int *base;
660 		int cnt;
661 
662 		id   = rb_entry(next, struct btf_id, rb_node);
663 		addr = id->addr[0];
664 		idx  = addr - obj->efile.idlist_addr;
665 
666 		/* sets are unique */
667 		if (id->addr_cnt != 1) {
668 			pr_err("FAILED malformed data for set '%s'\n",
669 				id->name);
670 			return -1;
671 		}
672 
673 		idx = idx / sizeof(int);
674 		base = &ptr[idx] + (id->is_set8 ? 2 : 1);
675 		cnt = ptr[idx];
676 
677 		pr_debug("sorting  addr %5lu: cnt %6d [%s]\n",
678 			 (idx + 1) * sizeof(int), cnt, id->name);
679 
680 		qsort(base, cnt, id->is_set8 ? sizeof(uint64_t) : sizeof(int), cmp_id);
681 
682 		next = rb_next(next);
683 	}
684 	return 0;
685 }
686 
symbols_patch(struct object * obj)687 static int symbols_patch(struct object *obj)
688 {
689 	int err;
690 
691 	if (__symbols_patch(obj, &obj->structs)  ||
692 	    __symbols_patch(obj, &obj->unions)   ||
693 	    __symbols_patch(obj, &obj->typedefs) ||
694 	    __symbols_patch(obj, &obj->funcs)    ||
695 	    __symbols_patch(obj, &obj->sets))
696 		return -1;
697 
698 	if (sets_patch(obj))
699 		return -1;
700 
701 	/* Set type to ensure endian translation occurs. */
702 	obj->efile.idlist->d_type = ELF_T_WORD;
703 
704 	elf_flagdata(obj->efile.idlist, ELF_C_SET, ELF_F_DIRTY);
705 
706 	err = elf_update(obj->efile.elf, ELF_C_WRITE);
707 	if (err < 0) {
708 		pr_err("FAILED elf_update(WRITE): %s\n",
709 			elf_errmsg(-1));
710 	}
711 
712 	pr_debug("update %s for %s\n",
713 		 err >= 0 ? "ok" : "failed", obj->path);
714 	return err < 0 ? -1 : 0;
715 }
716 
717 static const char * const resolve_btfids_usage[] = {
718 	"resolve_btfids [<options>] <ELF object>",
719 	NULL
720 };
721 
main(int argc,const char ** argv)722 int main(int argc, const char **argv)
723 {
724 	struct object obj = {
725 		.efile = {
726 			.idlist_shndx  = -1,
727 			.symbols_shndx = -1,
728 		},
729 		.structs  = RB_ROOT,
730 		.unions   = RB_ROOT,
731 		.typedefs = RB_ROOT,
732 		.funcs    = RB_ROOT,
733 		.sets     = RB_ROOT,
734 	};
735 	struct option btfid_options[] = {
736 		OPT_INCR('v', "verbose", &verbose,
737 			 "be more verbose (show errors, etc)"),
738 		OPT_STRING(0, "btf", &obj.btf, "BTF data",
739 			   "BTF data"),
740 		OPT_STRING('b', "btf_base", &obj.base_btf_path, "file",
741 			   "path of file providing base BTF"),
742 		OPT_END()
743 	};
744 	int err = -1;
745 
746 	argc = parse_options(argc, argv, btfid_options, resolve_btfids_usage,
747 			     PARSE_OPT_STOP_AT_NON_OPTION);
748 	if (argc != 1)
749 		usage_with_options(resolve_btfids_usage, btfid_options);
750 
751 	obj.path = argv[0];
752 
753 	if (elf_collect(&obj))
754 		goto out;
755 
756 	/*
757 	 * We did not find .BTF_ids section or symbols section,
758 	 * nothing to do..
759 	 */
760 	if (obj.efile.idlist_shndx == -1 ||
761 	    obj.efile.symbols_shndx == -1) {
762 		pr_debug("Cannot find .BTF_ids or symbols sections, nothing to do\n");
763 		err = 0;
764 		goto out;
765 	}
766 
767 	if (symbols_collect(&obj))
768 		goto out;
769 
770 	if (symbols_resolve(&obj))
771 		goto out;
772 
773 	if (symbols_patch(&obj))
774 		goto out;
775 
776 	err = 0;
777 out:
778 	if (obj.efile.elf) {
779 		elf_end(obj.efile.elf);
780 		close(obj.efile.fd);
781 	}
782 	return err;
783 }
784