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/btf_ids.h>
74#include <linux/rbtree.h>
75#include <linux/zalloc.h>
76#include <linux/err.h>
77#include <bpf/btf.h>
78#include <bpf/libbpf.h>
79#include <subcmd/parse-options.h>
80
81#define BTF_IDS_SECTION	".BTF_ids"
82#define BTF_ID_PREFIX	"__BTF_ID__"
83
84#define BTF_STRUCT	"struct"
85#define BTF_UNION	"union"
86#define BTF_TYPEDEF	"typedef"
87#define BTF_FUNC	"func"
88#define BTF_SET		"set"
89#define BTF_SET8	"set8"
90
91#define ADDR_CNT	100
92
93#if __BYTE_ORDER == __LITTLE_ENDIAN
94# define ELFDATANATIVE	ELFDATA2LSB
95#elif __BYTE_ORDER == __BIG_ENDIAN
96# define ELFDATANATIVE	ELFDATA2MSB
97#else
98# error "Unknown machine endianness!"
99#endif
100
101struct btf_id {
102	struct rb_node	 rb_node;
103	char		*name;
104	union {
105		int	 id;
106		int	 cnt;
107	};
108	int		 addr_cnt;
109	bool		 is_set;
110	bool		 is_set8;
111	Elf64_Addr	 addr[ADDR_CNT];
112};
113
114struct object {
115	const char *path;
116	const char *btf;
117	const char *base_btf_path;
118
119	struct {
120		int		 fd;
121		Elf		*elf;
122		Elf_Data	*symbols;
123		Elf_Data	*idlist;
124		int		 symbols_shndx;
125		int		 idlist_shndx;
126		size_t		 strtabidx;
127		unsigned long	 idlist_addr;
128		int		 encoding;
129	} efile;
130
131	struct rb_root	sets;
132	struct rb_root	structs;
133	struct rb_root	unions;
134	struct rb_root	typedefs;
135	struct rb_root	funcs;
136
137	int nr_funcs;
138	int nr_structs;
139	int nr_unions;
140	int nr_typedefs;
141};
142
143static int verbose;
144
145static int eprintf(int level, int var, const char *fmt, ...)
146{
147	va_list args;
148	int ret = 0;
149
150	if (var >= level) {
151		va_start(args, fmt);
152		ret = vfprintf(stderr, fmt, args);
153		va_end(args);
154	}
155	return ret;
156}
157
158#ifndef pr_fmt
159#define pr_fmt(fmt) fmt
160#endif
161
162#define pr_debug(fmt, ...) \
163	eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__)
164#define pr_debugN(n, fmt, ...) \
165	eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__)
166#define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__)
167#define pr_err(fmt, ...) \
168	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
169#define pr_info(fmt, ...) \
170	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
171
172static bool is_btf_id(const char *name)
173{
174	return name && !strncmp(name, BTF_ID_PREFIX, sizeof(BTF_ID_PREFIX) - 1);
175}
176
177static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
178{
179	struct rb_node *p = root->rb_node;
180	struct btf_id *id;
181	int cmp;
182
183	while (p) {
184		id = rb_entry(p, struct btf_id, rb_node);
185		cmp = strcmp(id->name, name);
186		if (cmp < 0)
187			p = p->rb_left;
188		else if (cmp > 0)
189			p = p->rb_right;
190		else
191			return id;
192	}
193	return NULL;
194}
195
196static struct btf_id *
197btf_id__add(struct rb_root *root, char *name, bool unique)
198{
199	struct rb_node **p = &root->rb_node;
200	struct rb_node *parent = NULL;
201	struct btf_id *id;
202	int cmp;
203
204	while (*p != NULL) {
205		parent = *p;
206		id = rb_entry(parent, struct btf_id, rb_node);
207		cmp = strcmp(id->name, name);
208		if (cmp < 0)
209			p = &(*p)->rb_left;
210		else if (cmp > 0)
211			p = &(*p)->rb_right;
212		else
213			return unique ? NULL : id;
214	}
215
216	id = zalloc(sizeof(*id));
217	if (id) {
218		pr_debug("adding symbol %s\n", name);
219		id->name = name;
220		rb_link_node(&id->rb_node, parent, p);
221		rb_insert_color(&id->rb_node, root);
222	}
223	return id;
224}
225
226static char *get_id(const char *prefix_end)
227{
228	/*
229	 * __BTF_ID__func__vfs_truncate__0
230	 * prefix_end =  ^
231	 * pos        =    ^
232	 */
233	int len = strlen(prefix_end);
234	int pos = sizeof("__") - 1;
235	char *p, *id;
236
237	if (pos >= len)
238		return NULL;
239
240	id = strdup(prefix_end + pos);
241	if (id) {
242		/*
243		 * __BTF_ID__func__vfs_truncate__0
244		 * id =            ^
245		 *
246		 * cut the unique id part
247		 */
248		p = strrchr(id, '_');
249		p--;
250		if (*p != '_') {
251			free(id);
252			return NULL;
253		}
254		*p = '\0';
255	}
256	return id;
257}
258
259static struct btf_id *add_set(struct object *obj, char *name, bool is_set8)
260{
261	/*
262	 * __BTF_ID__set__name
263	 * name =    ^
264	 * id   =         ^
265	 */
266	char *id = name + (is_set8 ? sizeof(BTF_SET8 "__") : sizeof(BTF_SET "__")) - 1;
267	int len = strlen(name);
268
269	if (id >= name + len) {
270		pr_err("FAILED to parse set name: %s\n", name);
271		return NULL;
272	}
273
274	return btf_id__add(&obj->sets, id, true);
275}
276
277static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
278{
279	char *id;
280
281	id = get_id(name + size);
282	if (!id) {
283		pr_err("FAILED to parse symbol name: %s\n", name);
284		return NULL;
285	}
286
287	return btf_id__add(root, id, false);
288}
289
290/* Older libelf.h and glibc elf.h might not yet define the ELF compression types. */
291#ifndef SHF_COMPRESSED
292#define SHF_COMPRESSED (1 << 11) /* Section with compressed data. */
293#endif
294
295/*
296 * The data of compressed section should be aligned to 4
297 * (for 32bit) or 8 (for 64 bit) bytes. The binutils ld
298 * sets sh_addralign to 1, which makes libelf fail with
299 * misaligned section error during the update:
300 *    FAILED elf_update(WRITE): invalid section alignment
301 *
302 * While waiting for ld fix, we fix the compressed sections
303 * sh_addralign value manualy.
304 */
305static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh)
306{
307	int expected = gelf_getclass(elf) == ELFCLASS32 ? 4 : 8;
308
309	if (!(sh->sh_flags & SHF_COMPRESSED))
310		return 0;
311
312	if (sh->sh_addralign == expected)
313		return 0;
314
315	pr_debug2(" - fixing wrong alignment sh_addralign %u, expected %u\n",
316		  sh->sh_addralign, expected);
317
318	sh->sh_addralign = expected;
319
320	if (gelf_update_shdr(scn, sh) == 0) {
321		pr_err("FAILED cannot update section header: %s\n",
322			elf_errmsg(-1));
323		return -1;
324	}
325	return 0;
326}
327
328static int elf_collect(struct object *obj)
329{
330	Elf_Scn *scn = NULL;
331	size_t shdrstrndx;
332	GElf_Ehdr ehdr;
333	int idx = 0;
334	Elf *elf;
335	int fd;
336
337	fd = open(obj->path, O_RDWR, 0666);
338	if (fd == -1) {
339		pr_err("FAILED cannot open %s: %s\n",
340			obj->path, strerror(errno));
341		return -1;
342	}
343
344	elf_version(EV_CURRENT);
345
346	elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL);
347	if (!elf) {
348		close(fd);
349		pr_err("FAILED cannot create ELF descriptor: %s\n",
350			elf_errmsg(-1));
351		return -1;
352	}
353
354	obj->efile.fd  = fd;
355	obj->efile.elf = elf;
356
357	elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT);
358
359	if (elf_getshdrstrndx(elf, &shdrstrndx) != 0) {
360		pr_err("FAILED cannot get shdr str ndx\n");
361		return -1;
362	}
363
364	if (gelf_getehdr(obj->efile.elf, &ehdr) == NULL) {
365		pr_err("FAILED cannot get ELF header: %s\n",
366			elf_errmsg(-1));
367		return -1;
368	}
369	obj->efile.encoding = ehdr.e_ident[EI_DATA];
370
371	/*
372	 * Scan all the elf sections and look for save data
373	 * from .BTF_ids section and symbols.
374	 */
375	while ((scn = elf_nextscn(elf, scn)) != NULL) {
376		Elf_Data *data;
377		GElf_Shdr sh;
378		char *name;
379
380		idx++;
381		if (gelf_getshdr(scn, &sh) != &sh) {
382			pr_err("FAILED get section(%d) header\n", idx);
383			return -1;
384		}
385
386		name = elf_strptr(elf, shdrstrndx, sh.sh_name);
387		if (!name) {
388			pr_err("FAILED get section(%d) name\n", idx);
389			return -1;
390		}
391
392		data = elf_getdata(scn, 0);
393		if (!data) {
394			pr_err("FAILED to get section(%d) data from %s\n",
395				idx, name);
396			return -1;
397		}
398
399		pr_debug2("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
400			  idx, name, (unsigned long) data->d_size,
401			  (int) sh.sh_link, (unsigned long) sh.sh_flags,
402			  (int) sh.sh_type);
403
404		if (sh.sh_type == SHT_SYMTAB) {
405			obj->efile.symbols       = data;
406			obj->efile.symbols_shndx = idx;
407			obj->efile.strtabidx     = sh.sh_link;
408		} else if (!strcmp(name, BTF_IDS_SECTION)) {
409			obj->efile.idlist       = data;
410			obj->efile.idlist_shndx = idx;
411			obj->efile.idlist_addr  = sh.sh_addr;
412		}
413
414		if (compressed_section_fix(elf, scn, &sh))
415			return -1;
416	}
417
418	return 0;
419}
420
421static int symbols_collect(struct object *obj)
422{
423	Elf_Scn *scn = NULL;
424	int n, i;
425	GElf_Shdr sh;
426	char *name;
427
428	scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
429	if (!scn)
430		return -1;
431
432	if (gelf_getshdr(scn, &sh) != &sh)
433		return -1;
434
435	n = sh.sh_size / sh.sh_entsize;
436
437	/*
438	 * Scan symbols and look for the ones starting with
439	 * __BTF_ID__* over .BTF_ids section.
440	 */
441	for (i = 0; i < n; i++) {
442		char *prefix;
443		struct btf_id *id;
444		GElf_Sym sym;
445
446		if (!gelf_getsym(obj->efile.symbols, i, &sym))
447			return -1;
448
449		if (sym.st_shndx != obj->efile.idlist_shndx)
450			continue;
451
452		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
453				  sym.st_name);
454
455		if (!is_btf_id(name))
456			continue;
457
458		/*
459		 * __BTF_ID__TYPE__vfs_truncate__0
460		 * prefix =  ^
461		 */
462		prefix = name + sizeof(BTF_ID_PREFIX) - 1;
463
464		/* struct */
465		if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) {
466			obj->nr_structs++;
467			id = add_symbol(&obj->structs, prefix, sizeof(BTF_STRUCT) - 1);
468		/* union  */
469		} else if (!strncmp(prefix, BTF_UNION, sizeof(BTF_UNION) - 1)) {
470			obj->nr_unions++;
471			id = add_symbol(&obj->unions, prefix, sizeof(BTF_UNION) - 1);
472		/* typedef */
473		} else if (!strncmp(prefix, BTF_TYPEDEF, sizeof(BTF_TYPEDEF) - 1)) {
474			obj->nr_typedefs++;
475			id = add_symbol(&obj->typedefs, prefix, sizeof(BTF_TYPEDEF) - 1);
476		/* func */
477		} else if (!strncmp(prefix, BTF_FUNC, sizeof(BTF_FUNC) - 1)) {
478			obj->nr_funcs++;
479			id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);
480		/* set8 */
481		} else if (!strncmp(prefix, BTF_SET8, sizeof(BTF_SET8) - 1)) {
482			id = add_set(obj, prefix, true);
483			/*
484			 * SET8 objects store list's count, which is encoded
485			 * in symbol's size, together with 'cnt' field hence
486			 * that - 1.
487			 */
488			if (id) {
489				id->cnt = sym.st_size / sizeof(uint64_t) - 1;
490				id->is_set8 = true;
491			}
492		/* set */
493		} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {
494			id = add_set(obj, prefix, false);
495			/*
496			 * SET objects store list's count, which is encoded
497			 * in symbol's size, together with 'cnt' field hence
498			 * that - 1.
499			 */
500			if (id) {
501				id->cnt = sym.st_size / sizeof(int) - 1;
502				id->is_set = true;
503			}
504		} else {
505			pr_err("FAILED unsupported prefix %s\n", prefix);
506			return -1;
507		}
508
509		if (!id)
510			return -ENOMEM;
511
512		if (id->addr_cnt >= ADDR_CNT) {
513			pr_err("FAILED symbol %s crossed the number of allowed lists\n",
514				id->name);
515			return -1;
516		}
517		id->addr[id->addr_cnt++] = sym.st_value;
518	}
519
520	return 0;
521}
522
523static int symbols_resolve(struct object *obj)
524{
525	int nr_typedefs = obj->nr_typedefs;
526	int nr_structs  = obj->nr_structs;
527	int nr_unions   = obj->nr_unions;
528	int nr_funcs    = obj->nr_funcs;
529	struct btf *base_btf = NULL;
530	int err, type_id;
531	struct btf *btf;
532	__u32 nr_types;
533
534	if (obj->base_btf_path) {
535		base_btf = btf__parse(obj->base_btf_path, NULL);
536		err = libbpf_get_error(base_btf);
537		if (err) {
538			pr_err("FAILED: load base BTF from %s: %s\n",
539			       obj->base_btf_path, strerror(-err));
540			return -1;
541		}
542	}
543
544	btf = btf__parse_split(obj->btf ?: obj->path, base_btf);
545	err = libbpf_get_error(btf);
546	if (err) {
547		pr_err("FAILED: load BTF from %s: %s\n",
548			obj->btf ?: obj->path, strerror(-err));
549		goto out;
550	}
551
552	err = -1;
553	nr_types = btf__type_cnt(btf);
554
555	/*
556	 * Iterate all the BTF types and search for collected symbol IDs.
557	 */
558	for (type_id = 1; type_id < nr_types; type_id++) {
559		const struct btf_type *type;
560		struct rb_root *root;
561		struct btf_id *id;
562		const char *str;
563		int *nr;
564
565		type = btf__type_by_id(btf, type_id);
566		if (!type) {
567			pr_err("FAILED: malformed BTF, can't resolve type for ID %d\n",
568				type_id);
569			goto out;
570		}
571
572		if (btf_is_func(type) && nr_funcs) {
573			nr   = &nr_funcs;
574			root = &obj->funcs;
575		} else if (btf_is_struct(type) && nr_structs) {
576			nr   = &nr_structs;
577			root = &obj->structs;
578		} else if (btf_is_union(type) && nr_unions) {
579			nr   = &nr_unions;
580			root = &obj->unions;
581		} else if (btf_is_typedef(type) && nr_typedefs) {
582			nr   = &nr_typedefs;
583			root = &obj->typedefs;
584		} else
585			continue;
586
587		str = btf__name_by_offset(btf, type->name_off);
588		if (!str) {
589			pr_err("FAILED: malformed BTF, can't resolve name for ID %d\n",
590				type_id);
591			goto out;
592		}
593
594		id = btf_id__find(root, str);
595		if (id) {
596			if (id->id) {
597				pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n",
598					str, id->id, type_id, id->id);
599			} else {
600				id->id = type_id;
601				(*nr)--;
602			}
603		}
604	}
605
606	err = 0;
607out:
608	btf__free(base_btf);
609	btf__free(btf);
610	return err;
611}
612
613static int id_patch(struct object *obj, struct btf_id *id)
614{
615	Elf_Data *data = obj->efile.idlist;
616	int *ptr = data->d_buf;
617	int i;
618
619	/* For set, set8, id->id may be 0 */
620	if (!id->id && !id->is_set && !id->is_set8)
621		pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
622
623	for (i = 0; i < id->addr_cnt; i++) {
624		unsigned long addr = id->addr[i];
625		unsigned long idx = addr - obj->efile.idlist_addr;
626
627		pr_debug("patching addr %5lu: ID %7d [%s]\n",
628			 idx, id->id, id->name);
629
630		if (idx >= data->d_size) {
631			pr_err("FAILED patching index %lu out of bounds %lu\n",
632				idx, data->d_size);
633			return -1;
634		}
635
636		idx = idx / sizeof(int);
637		ptr[idx] = id->id;
638	}
639
640	return 0;
641}
642
643static int __symbols_patch(struct object *obj, struct rb_root *root)
644{
645	struct rb_node *next;
646	struct btf_id *id;
647
648	next = rb_first(root);
649	while (next) {
650		id = rb_entry(next, struct btf_id, rb_node);
651
652		if (id_patch(obj, id))
653			return -1;
654
655		next = rb_next(next);
656	}
657	return 0;
658}
659
660static int cmp_id(const void *pa, const void *pb)
661{
662	const int *a = pa, *b = pb;
663
664	return *a - *b;
665}
666
667static int sets_patch(struct object *obj)
668{
669	Elf_Data *data = obj->efile.idlist;
670	struct rb_node *next;
671
672	next = rb_first(&obj->sets);
673	while (next) {
674		struct btf_id_set8 *set8;
675		struct btf_id_set *set;
676		unsigned long addr, off;
677		struct btf_id *id;
678
679		id   = rb_entry(next, struct btf_id, rb_node);
680		addr = id->addr[0];
681		off = addr - obj->efile.idlist_addr;
682
683		/* sets are unique */
684		if (id->addr_cnt != 1) {
685			pr_err("FAILED malformed data for set '%s'\n",
686				id->name);
687			return -1;
688		}
689
690		if (id->is_set) {
691			set = data->d_buf + off;
692			qsort(set->ids, set->cnt, sizeof(set->ids[0]), cmp_id);
693		} else {
694			set8 = data->d_buf + off;
695			/*
696			 * Make sure id is at the beginning of the pairs
697			 * struct, otherwise the below qsort would not work.
698			 */
699			BUILD_BUG_ON(set8->pairs != &set8->pairs[0].id);
700			qsort(set8->pairs, set8->cnt, sizeof(set8->pairs[0]), cmp_id);
701
702			/*
703			 * When ELF endianness does not match endianness of the
704			 * host, libelf will do the translation when updating
705			 * the ELF. This, however, corrupts SET8 flags which are
706			 * already in the target endianness. So, let's bswap
707			 * them to the host endianness and libelf will then
708			 * correctly translate everything.
709			 */
710			if (obj->efile.encoding != ELFDATANATIVE) {
711				int i;
712
713				set8->flags = bswap_32(set8->flags);
714				for (i = 0; i < set8->cnt; i++) {
715					set8->pairs[i].flags =
716						bswap_32(set8->pairs[i].flags);
717				}
718			}
719		}
720
721		pr_debug("sorting  addr %5lu: cnt %6d [%s]\n",
722			 off, id->is_set ? set->cnt : set8->cnt, id->name);
723
724		next = rb_next(next);
725	}
726	return 0;
727}
728
729static int symbols_patch(struct object *obj)
730{
731	int err;
732
733	if (__symbols_patch(obj, &obj->structs)  ||
734	    __symbols_patch(obj, &obj->unions)   ||
735	    __symbols_patch(obj, &obj->typedefs) ||
736	    __symbols_patch(obj, &obj->funcs)    ||
737	    __symbols_patch(obj, &obj->sets))
738		return -1;
739
740	if (sets_patch(obj))
741		return -1;
742
743	/* Set type to ensure endian translation occurs. */
744	obj->efile.idlist->d_type = ELF_T_WORD;
745
746	elf_flagdata(obj->efile.idlist, ELF_C_SET, ELF_F_DIRTY);
747
748	err = elf_update(obj->efile.elf, ELF_C_WRITE);
749	if (err < 0) {
750		pr_err("FAILED elf_update(WRITE): %s\n",
751			elf_errmsg(-1));
752	}
753
754	pr_debug("update %s for %s\n",
755		 err >= 0 ? "ok" : "failed", obj->path);
756	return err < 0 ? -1 : 0;
757}
758
759static const char * const resolve_btfids_usage[] = {
760	"resolve_btfids [<options>] <ELF object>",
761	NULL
762};
763
764int main(int argc, const char **argv)
765{
766	struct object obj = {
767		.efile = {
768			.idlist_shndx  = -1,
769			.symbols_shndx = -1,
770		},
771		.structs  = RB_ROOT,
772		.unions   = RB_ROOT,
773		.typedefs = RB_ROOT,
774		.funcs    = RB_ROOT,
775		.sets     = RB_ROOT,
776	};
777	struct option btfid_options[] = {
778		OPT_INCR('v', "verbose", &verbose,
779			 "be more verbose (show errors, etc)"),
780		OPT_STRING(0, "btf", &obj.btf, "BTF data",
781			   "BTF data"),
782		OPT_STRING('b', "btf_base", &obj.base_btf_path, "file",
783			   "path of file providing base BTF"),
784		OPT_END()
785	};
786	int err = -1;
787
788	argc = parse_options(argc, argv, btfid_options, resolve_btfids_usage,
789			     PARSE_OPT_STOP_AT_NON_OPTION);
790	if (argc != 1)
791		usage_with_options(resolve_btfids_usage, btfid_options);
792
793	obj.path = argv[0];
794
795	if (elf_collect(&obj))
796		goto out;
797
798	/*
799	 * We did not find .BTF_ids section or symbols section,
800	 * nothing to do..
801	 */
802	if (obj.efile.idlist_shndx == -1 ||
803	    obj.efile.symbols_shndx == -1) {
804		pr_debug("Cannot find .BTF_ids or symbols sections, nothing to do\n");
805		err = 0;
806		goto out;
807	}
808
809	if (symbols_collect(&obj))
810		goto out;
811
812	if (symbols_resolve(&obj))
813		goto out;
814
815	if (symbols_patch(&obj))
816		goto out;
817
818	err = 0;
819out:
820	if (obj.efile.elf) {
821		elf_end(obj.efile.elf);
822		close(obj.efile.fd);
823	}
824	return err;
825}
826