main.c

  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;
144static int warnings;
145
146static int eprintf(int level, int var, const char *fmt, ...)
147{
148	va_list args;
149	int ret = 0;
150
151	if (var >= level) {
152		va_start(args, fmt);
153		ret = vfprintf(stderr, fmt, args);
154		va_end(args);
155	}
156	return ret;
157}
158
159#ifndef pr_fmt
160#define pr_fmt(fmt) fmt
161#endif
162
163#define pr_debug(fmt, ...) \
164	eprintf(1, verbose, pr_fmt(fmt), ##__VA_ARGS__)
165#define pr_debugN(n, fmt, ...) \
166	eprintf(n, verbose, pr_fmt(fmt), ##__VA_ARGS__)
167#define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__)
168#define pr_err(fmt, ...) \
169	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
170#define pr_info(fmt, ...) \
171	eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__)
172
173static bool is_btf_id(const char *name)
174{
175	return name && !strncmp(name, BTF_ID_PREFIX, sizeof(BTF_ID_PREFIX) - 1);
176}
177
178static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
179{
180	struct rb_node *p = root->rb_node;
181	struct btf_id *id;
182	int cmp;
183
184	while (p) {
185		id = rb_entry(p, struct btf_id, rb_node);
186		cmp = strcmp(id->name, name);
187		if (cmp < 0)
188			p = p->rb_left;
189		else if (cmp > 0)
190			p = p->rb_right;
191		else
192			return id;
193	}
194	return NULL;
195}
196
197static struct btf_id *
198btf_id__add(struct rb_root *root, char *name, bool unique)
199{
200	struct rb_node **p = &root->rb_node;
201	struct rb_node *parent = NULL;
202	struct btf_id *id;
203	int cmp;
204
205	while (*p != NULL) {
206		parent = *p;
207		id = rb_entry(parent, struct btf_id, rb_node);
208		cmp = strcmp(id->name, name);
209		if (cmp < 0)
210			p = &(*p)->rb_left;
211		else if (cmp > 0)
212			p = &(*p)->rb_right;
213		else
214			return unique ? NULL : id;
215	}
216
217	id = zalloc(sizeof(*id));
218	if (id) {
219		pr_debug("adding symbol %s\n", name);
220		id->name = name;
221		rb_link_node(&id->rb_node, parent, p);
222		rb_insert_color(&id->rb_node, root);
223	}
224	return id;
225}
226
227static char *get_id(const char *prefix_end)
228{
229	/*
230	 * __BTF_ID__func__vfs_truncate__0
231	 * prefix_end =  ^
232	 * pos        =    ^
233	 */
234	int len = strlen(prefix_end);
235	int pos = sizeof("__") - 1;
236	char *p, *id;
237
238	if (pos >= len)
239		return NULL;
240
241	id = strdup(prefix_end + pos);
242	if (id) {
243		/*
244		 * __BTF_ID__func__vfs_truncate__0
245		 * id =            ^
246		 *
247		 * cut the unique id part
248		 */
249		p = strrchr(id, '_');
250		p--;
251		if (*p != '_') {
252			free(id);
253			return NULL;
254		}
255		*p = '\0';
256	}
257	return id;
258}
259
260static struct btf_id *add_set(struct object *obj, char *name, bool is_set8)
261{
262	/*
263	 * __BTF_ID__set__name
264	 * name =    ^
265	 * id   =         ^
266	 */
267	char *id = name + (is_set8 ? sizeof(BTF_SET8 "__") : sizeof(BTF_SET "__")) - 1;
268	int len = strlen(name);
269
270	if (id >= name + len) {
271		pr_err("FAILED to parse set name: %s\n", name);
272		return NULL;
273	}
274
275	return btf_id__add(&obj->sets, id, true);
276}
277
278static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
279{
280	char *id;
281
282	id = get_id(name + size);
283	if (!id) {
284		pr_err("FAILED to parse symbol name: %s\n", name);
285		return NULL;
286	}
287
288	return btf_id__add(root, id, false);
289}
290
291/* Older libelf.h and glibc elf.h might not yet define the ELF compression types. */
292#ifndef SHF_COMPRESSED
293#define SHF_COMPRESSED (1 << 11) /* Section with compressed data. */
294#endif
295
296/*
297 * The data of compressed section should be aligned to 4
298 * (for 32bit) or 8 (for 64 bit) bytes. The binutils ld
299 * sets sh_addralign to 1, which makes libelf fail with
300 * misaligned section error during the update:
301 *    FAILED elf_update(WRITE): invalid section alignment
302 *
303 * While waiting for ld fix, we fix the compressed sections
304 * sh_addralign value manualy.
305 */
306static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh)
307{
308	int expected = gelf_getclass(elf) == ELFCLASS32 ? 4 : 8;
309
310	if (!(sh->sh_flags & SHF_COMPRESSED))
311		return 0;
312
313	if (sh->sh_addralign == expected)
314		return 0;
315
316	pr_debug2(" - fixing wrong alignment sh_addralign %u, expected %u\n",
317		  sh->sh_addralign, expected);
318
319	sh->sh_addralign = expected;
320
321	if (gelf_update_shdr(scn, sh) == 0) {
322		pr_err("FAILED cannot update section header: %s\n",
323			elf_errmsg(-1));
324		return -1;
325	}
326	return 0;
327}
328
329static int elf_collect(struct object *obj)
330{
331	Elf_Scn *scn = NULL;
332	size_t shdrstrndx;
333	GElf_Ehdr ehdr;
334	int idx = 0;
335	Elf *elf;
336	int fd;
337
338	fd = open(obj->path, O_RDWR, 0666);
339	if (fd == -1) {
340		pr_err("FAILED cannot open %s: %s\n",
341			obj->path, strerror(errno));
342		return -1;
343	}
344
345	elf_version(EV_CURRENT);
346
347	elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL);
348	if (!elf) {
349		close(fd);
350		pr_err("FAILED cannot create ELF descriptor: %s\n",
351			elf_errmsg(-1));
352		return -1;
353	}
354
355	obj->efile.fd  = fd;
356	obj->efile.elf = elf;
357
358	elf_flagelf(elf, ELF_C_SET, ELF_F_LAYOUT);
359
360	if (elf_getshdrstrndx(elf, &shdrstrndx) != 0) {
361		pr_err("FAILED cannot get shdr str ndx\n");
362		return -1;
363	}
364
365	if (gelf_getehdr(obj->efile.elf, &ehdr) == NULL) {
366		pr_err("FAILED cannot get ELF header: %s\n",
367			elf_errmsg(-1));
368		return -1;
369	}
370	obj->efile.encoding = ehdr.e_ident[EI_DATA];
371
372	/*
373	 * Scan all the elf sections and look for save data
374	 * from .BTF_ids section and symbols.
375	 */
376	while ((scn = elf_nextscn(elf, scn)) != NULL) {
377		Elf_Data *data;
378		GElf_Shdr sh;
379		char *name;
380
381		idx++;
382		if (gelf_getshdr(scn, &sh) != &sh) {
383			pr_err("FAILED get section(%d) header\n", idx);
384			return -1;
385		}
386
387		name = elf_strptr(elf, shdrstrndx, sh.sh_name);
388		if (!name) {
389			pr_err("FAILED get section(%d) name\n", idx);
390			return -1;
391		}
392
393		data = elf_getdata(scn, 0);
394		if (!data) {
395			pr_err("FAILED to get section(%d) data from %s\n",
396				idx, name);
397			return -1;
398		}
399
400		pr_debug2("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
401			  idx, name, (unsigned long) data->d_size,
402			  (int) sh.sh_link, (unsigned long) sh.sh_flags,
403			  (int) sh.sh_type);
404
405		if (sh.sh_type == SHT_SYMTAB) {
406			obj->efile.symbols       = data;
407			obj->efile.symbols_shndx = idx;
408			obj->efile.strtabidx     = sh.sh_link;
409		} else if (!strcmp(name, BTF_IDS_SECTION)) {
410			obj->efile.idlist       = data;
411			obj->efile.idlist_shndx = idx;
412			obj->efile.idlist_addr  = sh.sh_addr;
413		} else if (!strcmp(name, BTF_BASE_ELF_SEC)) {
414			/* If a .BTF.base section is found, do not resolve
415			 * BTF ids relative to vmlinux; resolve relative
416			 * to the .BTF.base section instead.  btf__parse_split()
417			 * will take care of this once the base BTF it is
418			 * passed is NULL.
419			 */
420			obj->base_btf_path = NULL;
421		}
422
423		if (compressed_section_fix(elf, scn, &sh))
424			return -1;
425	}
426
427	return 0;
428}
429
430static int symbols_collect(struct object *obj)
431{
432	Elf_Scn *scn = NULL;
433	int n, i;
434	GElf_Shdr sh;
435	char *name;
436
437	scn = elf_getscn(obj->efile.elf, obj->efile.symbols_shndx);
438	if (!scn)
439		return -1;
440
441	if (gelf_getshdr(scn, &sh) != &sh)
442		return -1;
443
444	n = sh.sh_size / sh.sh_entsize;
445
446	/*
447	 * Scan symbols and look for the ones starting with
448	 * __BTF_ID__* over .BTF_ids section.
449	 */
450	for (i = 0; i < n; i++) {
451		char *prefix;
452		struct btf_id *id;
453		GElf_Sym sym;
454
455		if (!gelf_getsym(obj->efile.symbols, i, &sym))
456			return -1;
457
458		if (sym.st_shndx != obj->efile.idlist_shndx)
459			continue;
460
461		name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
462				  sym.st_name);
463
464		if (!is_btf_id(name))
465			continue;
466
467		/*
468		 * __BTF_ID__TYPE__vfs_truncate__0
469		 * prefix =  ^
470		 */
471		prefix = name + sizeof(BTF_ID_PREFIX) - 1;
472
473		/* struct */
474		if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) {
475			obj->nr_structs++;
476			id = add_symbol(&obj->structs, prefix, sizeof(BTF_STRUCT) - 1);
477		/* union  */
478		} else if (!strncmp(prefix, BTF_UNION, sizeof(BTF_UNION) - 1)) {
479			obj->nr_unions++;
480			id = add_symbol(&obj->unions, prefix, sizeof(BTF_UNION) - 1);
481		/* typedef */
482		} else if (!strncmp(prefix, BTF_TYPEDEF, sizeof(BTF_TYPEDEF) - 1)) {
483			obj->nr_typedefs++;
484			id = add_symbol(&obj->typedefs, prefix, sizeof(BTF_TYPEDEF) - 1);
485		/* func */
486		} else if (!strncmp(prefix, BTF_FUNC, sizeof(BTF_FUNC) - 1)) {
487			obj->nr_funcs++;
488			id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);
489		/* set8 */
490		} else if (!strncmp(prefix, BTF_SET8, sizeof(BTF_SET8) - 1)) {
491			id = add_set(obj, prefix, true);
492			/*
493			 * SET8 objects store list's count, which is encoded
494			 * in symbol's size, together with 'cnt' field hence
495			 * that - 1.
496			 */
497			if (id) {
498				id->cnt = sym.st_size / sizeof(uint64_t) - 1;
499				id->is_set8 = true;
500			}
501		/* set */
502		} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {
503			id = add_set(obj, prefix, false);
504			/*
505			 * SET objects store list's count, which is encoded
506			 * in symbol's size, together with 'cnt' field hence
507			 * that - 1.
508			 */
509			if (id) {
510				id->cnt = sym.st_size / sizeof(int) - 1;
511				id->is_set = true;
512			}
513		} else {
514			pr_err("FAILED unsupported prefix %s\n", prefix);
515			return -1;
516		}
517
518		if (!id)
519			return -ENOMEM;
520
521		if (id->addr_cnt >= ADDR_CNT) {
522			pr_err("FAILED symbol %s crossed the number of allowed lists\n",
523				id->name);
524			return -1;
525		}
526		id->addr[id->addr_cnt++] = sym.st_value;
527	}
528
529	return 0;
530}
531
532static int symbols_resolve(struct object *obj)
533{
534	int nr_typedefs = obj->nr_typedefs;
535	int nr_structs  = obj->nr_structs;
536	int nr_unions   = obj->nr_unions;
537	int nr_funcs    = obj->nr_funcs;
538	struct btf *base_btf = NULL;
539	int err, type_id;
540	struct btf *btf;
541	__u32 nr_types;
542
543	if (obj->base_btf_path) {
544		base_btf = btf__parse(obj->base_btf_path, NULL);
545		err = libbpf_get_error(base_btf);
546		if (err) {
547			pr_err("FAILED: load base BTF from %s: %s\n",
548			       obj->base_btf_path, strerror(-err));
549			return -1;
550		}
551	}
552
553	btf = btf__parse_split(obj->btf ?: obj->path, base_btf);
554	err = libbpf_get_error(btf);
555	if (err) {
556		pr_err("FAILED: load BTF from %s: %s\n",
557			obj->btf ?: obj->path, strerror(-err));
558		goto out;
559	}
560
561	err = -1;
562	nr_types = btf__type_cnt(btf);
563
564	/*
565	 * Iterate all the BTF types and search for collected symbol IDs.
566	 */
567	for (type_id = 1; type_id < nr_types; type_id++) {
568		const struct btf_type *type;
569		struct rb_root *root;
570		struct btf_id *id;
571		const char *str;
572		int *nr;
573
574		type = btf__type_by_id(btf, type_id);
575		if (!type) {
576			pr_err("FAILED: malformed BTF, can't resolve type for ID %d\n",
577				type_id);
578			goto out;
579		}
580
581		if (btf_is_func(type) && nr_funcs) {
582			nr   = &nr_funcs;
583			root = &obj->funcs;
584		} else if (btf_is_struct(type) && nr_structs) {
585			nr   = &nr_structs;
586			root = &obj->structs;
587		} else if (btf_is_union(type) && nr_unions) {
588			nr   = &nr_unions;
589			root = &obj->unions;
590		} else if (btf_is_typedef(type) && nr_typedefs) {
591			nr   = &nr_typedefs;
592			root = &obj->typedefs;
593		} else
594			continue;
595
596		str = btf__name_by_offset(btf, type->name_off);
597		if (!str) {
598			pr_err("FAILED: malformed BTF, can't resolve name for ID %d\n",
599				type_id);
600			goto out;
601		}
602
603		id = btf_id__find(root, str);
604		if (id) {
605			if (id->id) {
606				pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n",
607					str, id->id, type_id, id->id);
608				warnings++;
609			} else {
610				id->id = type_id;
611				(*nr)--;
612			}
613		}
614	}
615
616	err = 0;
617out:
618	btf__free(base_btf);
619	btf__free(btf);
620	return err;
621}
622
623static int id_patch(struct object *obj, struct btf_id *id)
624{
625	Elf_Data *data = obj->efile.idlist;
626	int *ptr = data->d_buf;
627	int i;
628
629	/* For set, set8, id->id may be 0 */
630	if (!id->id && !id->is_set && !id->is_set8) {
631		pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);
632		warnings++;
633	}
634
635	for (i = 0; i < id->addr_cnt; i++) {
636		unsigned long addr = id->addr[i];
637		unsigned long idx = addr - obj->efile.idlist_addr;
638
639		pr_debug("patching addr %5lu: ID %7d [%s]\n",
640			 idx, id->id, id->name);
641
642		if (idx >= data->d_size) {
643			pr_err("FAILED patching index %lu out of bounds %lu\n",
644				idx, data->d_size);
645			return -1;
646		}
647
648		idx = idx / sizeof(int);
649		ptr[idx] = id->id;
650	}
651
652	return 0;
653}
654
655static int __symbols_patch(struct object *obj, struct rb_root *root)
656{
657	struct rb_node *next;
658	struct btf_id *id;
659
660	next = rb_first(root);
661	while (next) {
662		id = rb_entry(next, struct btf_id, rb_node);
663
664		if (id_patch(obj, id))
665			return -1;
666
667		next = rb_next(next);
668	}
669	return 0;
670}
671
672static int cmp_id(const void *pa, const void *pb)
673{
674	const int *a = pa, *b = pb;
675
676	return *a - *b;
677}
678
679static int sets_patch(struct object *obj)
680{
681	Elf_Data *data = obj->efile.idlist;
682	struct rb_node *next;
683
684	next = rb_first(&obj->sets);
685	while (next) {
686		struct btf_id_set8 *set8 = NULL;
687		struct btf_id_set *set = NULL;
688		unsigned long addr, off;
689		struct btf_id *id;
690
691		id   = rb_entry(next, struct btf_id, rb_node);
692		addr = id->addr[0];
693		off = addr - obj->efile.idlist_addr;
694
695		/* sets are unique */
696		if (id->addr_cnt != 1) {
697			pr_err("FAILED malformed data for set '%s'\n",
698				id->name);
699			return -1;
700		}
701
702		if (id->is_set) {
703			set = data->d_buf + off;
704			qsort(set->ids, set->cnt, sizeof(set->ids[0]), cmp_id);
705		} else {
706			set8 = data->d_buf + off;
707			/*
708			 * Make sure id is at the beginning of the pairs
709			 * struct, otherwise the below qsort would not work.
710			 */
711			BUILD_BUG_ON((u32 *)set8->pairs != &set8->pairs[0].id);
712			qsort(set8->pairs, set8->cnt, sizeof(set8->pairs[0]), cmp_id);
713
714			/*
715			 * When ELF endianness does not match endianness of the
716			 * host, libelf will do the translation when updating
717			 * the ELF. This, however, corrupts SET8 flags which are
718			 * already in the target endianness. So, let's bswap
719			 * them to the host endianness and libelf will then
720			 * correctly translate everything.
721			 */
722			if (obj->efile.encoding != ELFDATANATIVE) {
723				int i;
724
725				set8->flags = bswap_32(set8->flags);
726				for (i = 0; i < set8->cnt; i++) {
727					set8->pairs[i].flags =
728						bswap_32(set8->pairs[i].flags);
729				}
730			}
731		}
732
733		pr_debug("sorting  addr %5lu: cnt %6d [%s]\n",
734			 off, id->is_set ? set->cnt : set8->cnt, id->name);
735
736		next = rb_next(next);
737	}
738	return 0;
739}
740
741static int symbols_patch(struct object *obj)
742{
743	off_t err;
744
745	if (__symbols_patch(obj, &obj->structs)  ||
746	    __symbols_patch(obj, &obj->unions)   ||
747	    __symbols_patch(obj, &obj->typedefs) ||
748	    __symbols_patch(obj, &obj->funcs)    ||
749	    __symbols_patch(obj, &obj->sets))
750		return -1;
751
752	if (sets_patch(obj))
753		return -1;
754
755	/* Set type to ensure endian translation occurs. */
756	obj->efile.idlist->d_type = ELF_T_WORD;
757
758	elf_flagdata(obj->efile.idlist, ELF_C_SET, ELF_F_DIRTY);
759
760	err = elf_update(obj->efile.elf, ELF_C_WRITE);
761	if (err < 0) {
762		pr_err("FAILED elf_update(WRITE): %s\n",
763			elf_errmsg(-1));
764	}
765
766	pr_debug("update %s for %s\n",
767		 err >= 0 ? "ok" : "failed", obj->path);
768	return err < 0 ? -1 : 0;
769}
770
771static const char * const resolve_btfids_usage[] = {
772	"resolve_btfids [<options>] <ELF object>",
773	NULL
774};
775
776int main(int argc, const char **argv)
777{
778	struct object obj = {
779		.efile = {
780			.idlist_shndx  = -1,
781			.symbols_shndx = -1,
782		},
783		.structs  = RB_ROOT,
784		.unions   = RB_ROOT,
785		.typedefs = RB_ROOT,
786		.funcs    = RB_ROOT,
787		.sets     = RB_ROOT,
788	};
789	bool fatal_warnings = false;
790	struct option btfid_options[] = {
791		OPT_INCR('v', "verbose", &verbose,
792			 "be more verbose (show errors, etc)"),
793		OPT_STRING(0, "btf", &obj.btf, "BTF data",
794			   "BTF data"),
795		OPT_STRING('b', "btf_base", &obj.base_btf_path, "file",
796			   "path of file providing base BTF"),
797		OPT_BOOLEAN(0, "fatal_warnings", &fatal_warnings,
798			    "turn warnings into errors"),
799		OPT_END()
800	};
801	int err = -1;
802
803	argc = parse_options(argc, argv, btfid_options, resolve_btfids_usage,
804			     PARSE_OPT_STOP_AT_NON_OPTION);
805	if (argc != 1)
806		usage_with_options(resolve_btfids_usage, btfid_options);
807
808	obj.path = argv[0];
809
810	if (elf_collect(&obj))
811		goto out;
812
813	/*
814	 * We did not find .BTF_ids section or symbols section,
815	 * nothing to do..
816	 */
817	if (obj.efile.idlist_shndx == -1 ||
818	    obj.efile.symbols_shndx == -1) {
819		pr_debug("Cannot find .BTF_ids or symbols sections, nothing to do\n");
820		err = 0;
821		goto out;
822	}
823
824	if (symbols_collect(&obj))
825		goto out;
826
827	if (symbols_resolve(&obj))
828		goto out;
829
830	if (symbols_patch(&obj))
831		goto out;
832
833	if (!(fatal_warnings && warnings))
834		err = 0;
835out:
836	if (obj.efile.elf) {
837		elf_end(obj.efile.elf);
838		close(obj.efile.fd);
839	}
840	return err;
841}