xref: /openbmc/linux/tools/objtool/elf.c (revision f20c7d91)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * elf.c - ELF access library
4  *
5  * Adapted from kpatch (https://github.com/dynup/kpatch):
6  * Copyright (C) 2013-2015 Josh Poimboeuf <jpoimboe@redhat.com>
7  * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
8  */
9 
10 #include <sys/types.h>
11 #include <sys/stat.h>
12 #include <fcntl.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include <unistd.h>
17 #include <errno.h>
18 #include "builtin.h"
19 
20 #include "elf.h"
21 #include "warn.h"
22 
23 #define MAX_NAME_LEN 128
24 
25 static inline u32 str_hash(const char *str)
26 {
27 	return jhash(str, strlen(str), 0);
28 }
29 
30 static inline int elf_hash_bits(void)
31 {
32 	return vmlinux ? ELF_HASH_BITS : 16;
33 }
34 
35 #define elf_hash_add(hashtable, node, key) \
36 	hlist_add_head(node, &hashtable[hash_min(key, elf_hash_bits())])
37 
38 static void elf_hash_init(struct hlist_head *table)
39 {
40 	__hash_init(table, 1U << elf_hash_bits());
41 }
42 
43 #define elf_hash_for_each_possible(name, obj, member, key)			\
44 	hlist_for_each_entry(obj, &name[hash_min(key, elf_hash_bits())], member)
45 
46 static void rb_add(struct rb_root *tree, struct rb_node *node,
47 		   int (*cmp)(struct rb_node *, const struct rb_node *))
48 {
49 	struct rb_node **link = &tree->rb_node;
50 	struct rb_node *parent = NULL;
51 
52 	while (*link) {
53 		parent = *link;
54 		if (cmp(node, parent) < 0)
55 			link = &parent->rb_left;
56 		else
57 			link = &parent->rb_right;
58 	}
59 
60 	rb_link_node(node, parent, link);
61 	rb_insert_color(node, tree);
62 }
63 
64 static struct rb_node *rb_find_first(const struct rb_root *tree, const void *key,
65 			       int (*cmp)(const void *key, const struct rb_node *))
66 {
67 	struct rb_node *node = tree->rb_node;
68 	struct rb_node *match = NULL;
69 
70 	while (node) {
71 		int c = cmp(key, node);
72 		if (c <= 0) {
73 			if (!c)
74 				match = node;
75 			node = node->rb_left;
76 		} else if (c > 0) {
77 			node = node->rb_right;
78 		}
79 	}
80 
81 	return match;
82 }
83 
84 static struct rb_node *rb_next_match(struct rb_node *node, const void *key,
85 				    int (*cmp)(const void *key, const struct rb_node *))
86 {
87 	node = rb_next(node);
88 	if (node && cmp(key, node))
89 		node = NULL;
90 	return node;
91 }
92 
93 #define rb_for_each(tree, node, key, cmp) \
94 	for ((node) = rb_find_first((tree), (key), (cmp)); \
95 	     (node); (node) = rb_next_match((node), (key), (cmp)))
96 
97 static int symbol_to_offset(struct rb_node *a, const struct rb_node *b)
98 {
99 	struct symbol *sa = rb_entry(a, struct symbol, node);
100 	struct symbol *sb = rb_entry(b, struct symbol, node);
101 
102 	if (sa->offset < sb->offset)
103 		return -1;
104 	if (sa->offset > sb->offset)
105 		return 1;
106 
107 	if (sa->len < sb->len)
108 		return -1;
109 	if (sa->len > sb->len)
110 		return 1;
111 
112 	sa->alias = sb;
113 
114 	return 0;
115 }
116 
117 static int symbol_by_offset(const void *key, const struct rb_node *node)
118 {
119 	const struct symbol *s = rb_entry(node, struct symbol, node);
120 	const unsigned long *o = key;
121 
122 	if (*o < s->offset)
123 		return -1;
124 	if (*o >= s->offset + s->len)
125 		return 1;
126 
127 	return 0;
128 }
129 
130 struct section *find_section_by_name(const struct elf *elf, const char *name)
131 {
132 	struct section *sec;
133 
134 	elf_hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name))
135 		if (!strcmp(sec->name, name))
136 			return sec;
137 
138 	return NULL;
139 }
140 
141 static struct section *find_section_by_index(struct elf *elf,
142 					     unsigned int idx)
143 {
144 	struct section *sec;
145 
146 	elf_hash_for_each_possible(elf->section_hash, sec, hash, idx)
147 		if (sec->idx == idx)
148 			return sec;
149 
150 	return NULL;
151 }
152 
153 static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
154 {
155 	struct symbol *sym;
156 
157 	elf_hash_for_each_possible(elf->symbol_hash, sym, hash, idx)
158 		if (sym->idx == idx)
159 			return sym;
160 
161 	return NULL;
162 }
163 
164 struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
165 {
166 	struct rb_node *node;
167 
168 	rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
169 		struct symbol *s = rb_entry(node, struct symbol, node);
170 
171 		if (s->offset == offset && s->type != STT_SECTION)
172 			return s;
173 	}
174 
175 	return NULL;
176 }
177 
178 struct symbol *find_func_by_offset(struct section *sec, unsigned long offset)
179 {
180 	struct rb_node *node;
181 
182 	rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
183 		struct symbol *s = rb_entry(node, struct symbol, node);
184 
185 		if (s->offset == offset && s->type == STT_FUNC)
186 			return s;
187 	}
188 
189 	return NULL;
190 }
191 
192 struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset)
193 {
194 	struct rb_node *node;
195 
196 	rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
197 		struct symbol *s = rb_entry(node, struct symbol, node);
198 
199 		if (s->type != STT_SECTION)
200 			return s;
201 	}
202 
203 	return NULL;
204 }
205 
206 struct symbol *find_func_containing(struct section *sec, unsigned long offset)
207 {
208 	struct rb_node *node;
209 
210 	rb_for_each(&sec->symbol_tree, node, &offset, symbol_by_offset) {
211 		struct symbol *s = rb_entry(node, struct symbol, node);
212 
213 		if (s->type == STT_FUNC)
214 			return s;
215 	}
216 
217 	return NULL;
218 }
219 
220 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
221 {
222 	struct symbol *sym;
223 
224 	elf_hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name))
225 		if (!strcmp(sym->name, name))
226 			return sym;
227 
228 	return NULL;
229 }
230 
231 struct rela *find_rela_by_dest_range(const struct elf *elf, struct section *sec,
232 				     unsigned long offset, unsigned int len)
233 {
234 	struct rela *rela, *r = NULL;
235 	unsigned long o;
236 
237 	if (!sec->rela)
238 		return NULL;
239 
240 	sec = sec->rela;
241 
242 	for_offset_range(o, offset, offset + len) {
243 		elf_hash_for_each_possible(elf->rela_hash, rela, hash,
244 				       sec_offset_hash(sec, o)) {
245 			if (rela->sec != sec)
246 				continue;
247 
248 			if (rela->offset >= offset && rela->offset < offset + len) {
249 				if (!r || rela->offset < r->offset)
250 					r = rela;
251 			}
252 		}
253 		if (r)
254 			return r;
255 	}
256 
257 	return NULL;
258 }
259 
260 struct rela *find_rela_by_dest(const struct elf *elf, struct section *sec, unsigned long offset)
261 {
262 	return find_rela_by_dest_range(elf, sec, offset, 1);
263 }
264 
265 static int read_sections(struct elf *elf)
266 {
267 	Elf_Scn *s = NULL;
268 	struct section *sec;
269 	size_t shstrndx, sections_nr;
270 	int i;
271 
272 	if (elf_getshdrnum(elf->elf, &sections_nr)) {
273 		WARN_ELF("elf_getshdrnum");
274 		return -1;
275 	}
276 
277 	if (elf_getshdrstrndx(elf->elf, &shstrndx)) {
278 		WARN_ELF("elf_getshdrstrndx");
279 		return -1;
280 	}
281 
282 	for (i = 0; i < sections_nr; i++) {
283 		sec = malloc(sizeof(*sec));
284 		if (!sec) {
285 			perror("malloc");
286 			return -1;
287 		}
288 		memset(sec, 0, sizeof(*sec));
289 
290 		INIT_LIST_HEAD(&sec->symbol_list);
291 		INIT_LIST_HEAD(&sec->rela_list);
292 
293 		s = elf_getscn(elf->elf, i);
294 		if (!s) {
295 			WARN_ELF("elf_getscn");
296 			return -1;
297 		}
298 
299 		sec->idx = elf_ndxscn(s);
300 
301 		if (!gelf_getshdr(s, &sec->sh)) {
302 			WARN_ELF("gelf_getshdr");
303 			return -1;
304 		}
305 
306 		sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);
307 		if (!sec->name) {
308 			WARN_ELF("elf_strptr");
309 			return -1;
310 		}
311 
312 		if (sec->sh.sh_size != 0) {
313 			sec->data = elf_getdata(s, NULL);
314 			if (!sec->data) {
315 				WARN_ELF("elf_getdata");
316 				return -1;
317 			}
318 			if (sec->data->d_off != 0 ||
319 			    sec->data->d_size != sec->sh.sh_size) {
320 				WARN("unexpected data attributes for %s",
321 				     sec->name);
322 				return -1;
323 			}
324 		}
325 		sec->len = sec->sh.sh_size;
326 
327 		list_add_tail(&sec->list, &elf->sections);
328 		elf_hash_add(elf->section_hash, &sec->hash, sec->idx);
329 		elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));
330 	}
331 
332 	if (stats)
333 		printf("nr_sections: %lu\n", (unsigned long)sections_nr);
334 
335 	/* sanity check, one more call to elf_nextscn() should return NULL */
336 	if (elf_nextscn(elf->elf, s)) {
337 		WARN("section entry mismatch");
338 		return -1;
339 	}
340 
341 	return 0;
342 }
343 
344 static int read_symbols(struct elf *elf)
345 {
346 	struct section *symtab, *symtab_shndx, *sec;
347 	struct symbol *sym, *pfunc;
348 	struct list_head *entry;
349 	struct rb_node *pnode;
350 	int symbols_nr, i;
351 	char *coldstr;
352 	Elf_Data *shndx_data = NULL;
353 	Elf32_Word shndx;
354 
355 	symtab = find_section_by_name(elf, ".symtab");
356 	if (!symtab) {
357 		WARN("missing symbol table");
358 		return -1;
359 	}
360 
361 	symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
362 	if (symtab_shndx)
363 		shndx_data = symtab_shndx->data;
364 
365 	symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;
366 
367 	for (i = 0; i < symbols_nr; i++) {
368 		sym = malloc(sizeof(*sym));
369 		if (!sym) {
370 			perror("malloc");
371 			return -1;
372 		}
373 		memset(sym, 0, sizeof(*sym));
374 		sym->alias = sym;
375 
376 		sym->idx = i;
377 
378 		if (!gelf_getsymshndx(symtab->data, shndx_data, i, &sym->sym,
379 				      &shndx)) {
380 			WARN_ELF("gelf_getsymshndx");
381 			goto err;
382 		}
383 
384 		sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
385 				       sym->sym.st_name);
386 		if (!sym->name) {
387 			WARN_ELF("elf_strptr");
388 			goto err;
389 		}
390 
391 		sym->type = GELF_ST_TYPE(sym->sym.st_info);
392 		sym->bind = GELF_ST_BIND(sym->sym.st_info);
393 
394 		if ((sym->sym.st_shndx > SHN_UNDEF &&
395 		     sym->sym.st_shndx < SHN_LORESERVE) ||
396 		    (shndx_data && sym->sym.st_shndx == SHN_XINDEX)) {
397 			if (sym->sym.st_shndx != SHN_XINDEX)
398 				shndx = sym->sym.st_shndx;
399 
400 			sym->sec = find_section_by_index(elf, shndx);
401 			if (!sym->sec) {
402 				WARN("couldn't find section for symbol %s",
403 				     sym->name);
404 				goto err;
405 			}
406 			if (sym->type == STT_SECTION) {
407 				sym->name = sym->sec->name;
408 				sym->sec->sym = sym;
409 			}
410 		} else
411 			sym->sec = find_section_by_index(elf, 0);
412 
413 		sym->offset = sym->sym.st_value;
414 		sym->len = sym->sym.st_size;
415 
416 		rb_add(&sym->sec->symbol_tree, &sym->node, symbol_to_offset);
417 		pnode = rb_prev(&sym->node);
418 		if (pnode)
419 			entry = &rb_entry(pnode, struct symbol, node)->list;
420 		else
421 			entry = &sym->sec->symbol_list;
422 		list_add(&sym->list, entry);
423 		elf_hash_add(elf->symbol_hash, &sym->hash, sym->idx);
424 		elf_hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name));
425 	}
426 
427 	if (stats)
428 		printf("nr_symbols: %lu\n", (unsigned long)symbols_nr);
429 
430 	/* Create parent/child links for any cold subfunctions */
431 	list_for_each_entry(sec, &elf->sections, list) {
432 		list_for_each_entry(sym, &sec->symbol_list, list) {
433 			char pname[MAX_NAME_LEN + 1];
434 			size_t pnamelen;
435 			if (sym->type != STT_FUNC)
436 				continue;
437 			sym->pfunc = sym->cfunc = sym;
438 			coldstr = strstr(sym->name, ".cold");
439 			if (!coldstr)
440 				continue;
441 
442 			pnamelen = coldstr - sym->name;
443 			if (pnamelen > MAX_NAME_LEN) {
444 				WARN("%s(): parent function name exceeds maximum length of %d characters",
445 				     sym->name, MAX_NAME_LEN);
446 				return -1;
447 			}
448 
449 			strncpy(pname, sym->name, pnamelen);
450 			pname[pnamelen] = '\0';
451 			pfunc = find_symbol_by_name(elf, pname);
452 
453 			if (!pfunc) {
454 				WARN("%s(): can't find parent function",
455 				     sym->name);
456 				return -1;
457 			}
458 
459 			sym->pfunc = pfunc;
460 			pfunc->cfunc = sym;
461 
462 			/*
463 			 * Unfortunately, -fnoreorder-functions puts the child
464 			 * inside the parent.  Remove the overlap so we can
465 			 * have sane assumptions.
466 			 *
467 			 * Note that pfunc->len now no longer matches
468 			 * pfunc->sym.st_size.
469 			 */
470 			if (sym->sec == pfunc->sec &&
471 			    sym->offset >= pfunc->offset &&
472 			    sym->offset + sym->len == pfunc->offset + pfunc->len) {
473 				pfunc->len -= sym->len;
474 			}
475 		}
476 	}
477 
478 	return 0;
479 
480 err:
481 	free(sym);
482 	return -1;
483 }
484 
485 void elf_add_rela(struct elf *elf, struct rela *rela)
486 {
487 	struct section *sec = rela->sec;
488 
489 	list_add_tail(&rela->list, &sec->rela_list);
490 	elf_hash_add(elf->rela_hash, &rela->hash, rela_hash(rela));
491 }
492 
493 static int read_relas(struct elf *elf)
494 {
495 	struct section *sec;
496 	struct rela *rela;
497 	int i;
498 	unsigned int symndx;
499 	unsigned long nr_rela, max_rela = 0, tot_rela = 0;
500 
501 	list_for_each_entry(sec, &elf->sections, list) {
502 		if (sec->sh.sh_type != SHT_RELA)
503 			continue;
504 
505 		sec->base = find_section_by_name(elf, sec->name + 5);
506 		if (!sec->base) {
507 			WARN("can't find base section for rela section %s",
508 			     sec->name);
509 			return -1;
510 		}
511 
512 		sec->base->rela = sec;
513 
514 		nr_rela = 0;
515 		for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) {
516 			rela = malloc(sizeof(*rela));
517 			if (!rela) {
518 				perror("malloc");
519 				return -1;
520 			}
521 			memset(rela, 0, sizeof(*rela));
522 
523 			if (!gelf_getrela(sec->data, i, &rela->rela)) {
524 				WARN_ELF("gelf_getrela");
525 				return -1;
526 			}
527 
528 			rela->type = GELF_R_TYPE(rela->rela.r_info);
529 			rela->addend = rela->rela.r_addend;
530 			rela->offset = rela->rela.r_offset;
531 			symndx = GELF_R_SYM(rela->rela.r_info);
532 			rela->sym = find_symbol_by_index(elf, symndx);
533 			rela->sec = sec;
534 			if (!rela->sym) {
535 				WARN("can't find rela entry symbol %d for %s",
536 				     symndx, sec->name);
537 				return -1;
538 			}
539 
540 			elf_add_rela(elf, rela);
541 			nr_rela++;
542 		}
543 		max_rela = max(max_rela, nr_rela);
544 		tot_rela += nr_rela;
545 	}
546 
547 	if (stats) {
548 		printf("max_rela: %lu\n", max_rela);
549 		printf("tot_rela: %lu\n", tot_rela);
550 	}
551 
552 	return 0;
553 }
554 
555 struct elf *elf_open_read(const char *name, int flags)
556 {
557 	struct elf *elf;
558 	Elf_Cmd cmd;
559 
560 	elf_version(EV_CURRENT);
561 
562 	elf = malloc(sizeof(*elf));
563 	if (!elf) {
564 		perror("malloc");
565 		return NULL;
566 	}
567 	memset(elf, 0, offsetof(struct elf, sections));
568 
569 	INIT_LIST_HEAD(&elf->sections);
570 
571 	elf_hash_init(elf->symbol_hash);
572 	elf_hash_init(elf->symbol_name_hash);
573 	elf_hash_init(elf->section_hash);
574 	elf_hash_init(elf->section_name_hash);
575 	elf_hash_init(elf->rela_hash);
576 
577 	elf->fd = open(name, flags);
578 	if (elf->fd == -1) {
579 		fprintf(stderr, "objtool: Can't open '%s': %s\n",
580 			name, strerror(errno));
581 		goto err;
582 	}
583 
584 	if ((flags & O_ACCMODE) == O_RDONLY)
585 		cmd = ELF_C_READ_MMAP;
586 	else if ((flags & O_ACCMODE) == O_RDWR)
587 		cmd = ELF_C_RDWR;
588 	else /* O_WRONLY */
589 		cmd = ELF_C_WRITE;
590 
591 	elf->elf = elf_begin(elf->fd, cmd, NULL);
592 	if (!elf->elf) {
593 		WARN_ELF("elf_begin");
594 		goto err;
595 	}
596 
597 	if (!gelf_getehdr(elf->elf, &elf->ehdr)) {
598 		WARN_ELF("gelf_getehdr");
599 		goto err;
600 	}
601 
602 	if (read_sections(elf))
603 		goto err;
604 
605 	if (read_symbols(elf))
606 		goto err;
607 
608 	if (read_relas(elf))
609 		goto err;
610 
611 	return elf;
612 
613 err:
614 	elf_close(elf);
615 	return NULL;
616 }
617 
618 struct section *elf_create_section(struct elf *elf, const char *name,
619 				   size_t entsize, int nr)
620 {
621 	struct section *sec, *shstrtab;
622 	size_t size = entsize * nr;
623 	Elf_Scn *s;
624 	Elf_Data *data;
625 
626 	sec = malloc(sizeof(*sec));
627 	if (!sec) {
628 		perror("malloc");
629 		return NULL;
630 	}
631 	memset(sec, 0, sizeof(*sec));
632 
633 	INIT_LIST_HEAD(&sec->symbol_list);
634 	INIT_LIST_HEAD(&sec->rela_list);
635 
636 	s = elf_newscn(elf->elf);
637 	if (!s) {
638 		WARN_ELF("elf_newscn");
639 		return NULL;
640 	}
641 
642 	sec->name = strdup(name);
643 	if (!sec->name) {
644 		perror("strdup");
645 		return NULL;
646 	}
647 
648 	sec->idx = elf_ndxscn(s);
649 	sec->len = size;
650 	sec->changed = true;
651 
652 	sec->data = elf_newdata(s);
653 	if (!sec->data) {
654 		WARN_ELF("elf_newdata");
655 		return NULL;
656 	}
657 
658 	sec->data->d_size = size;
659 	sec->data->d_align = 1;
660 
661 	if (size) {
662 		sec->data->d_buf = malloc(size);
663 		if (!sec->data->d_buf) {
664 			perror("malloc");
665 			return NULL;
666 		}
667 		memset(sec->data->d_buf, 0, size);
668 	}
669 
670 	if (!gelf_getshdr(s, &sec->sh)) {
671 		WARN_ELF("gelf_getshdr");
672 		return NULL;
673 	}
674 
675 	sec->sh.sh_size = size;
676 	sec->sh.sh_entsize = entsize;
677 	sec->sh.sh_type = SHT_PROGBITS;
678 	sec->sh.sh_addralign = 1;
679 	sec->sh.sh_flags = SHF_ALLOC;
680 
681 
682 	/* Add section name to .shstrtab (or .strtab for Clang) */
683 	shstrtab = find_section_by_name(elf, ".shstrtab");
684 	if (!shstrtab)
685 		shstrtab = find_section_by_name(elf, ".strtab");
686 	if (!shstrtab) {
687 		WARN("can't find .shstrtab or .strtab section");
688 		return NULL;
689 	}
690 
691 	s = elf_getscn(elf->elf, shstrtab->idx);
692 	if (!s) {
693 		WARN_ELF("elf_getscn");
694 		return NULL;
695 	}
696 
697 	data = elf_newdata(s);
698 	if (!data) {
699 		WARN_ELF("elf_newdata");
700 		return NULL;
701 	}
702 
703 	data->d_buf = sec->name;
704 	data->d_size = strlen(name) + 1;
705 	data->d_align = 1;
706 
707 	sec->sh.sh_name = shstrtab->len;
708 
709 	shstrtab->len += strlen(name) + 1;
710 	shstrtab->changed = true;
711 
712 	list_add_tail(&sec->list, &elf->sections);
713 	elf_hash_add(elf->section_hash, &sec->hash, sec->idx);
714 	elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));
715 
716 	return sec;
717 }
718 
719 struct section *elf_create_rela_section(struct elf *elf, struct section *base)
720 {
721 	char *relaname;
722 	struct section *sec;
723 
724 	relaname = malloc(strlen(base->name) + strlen(".rela") + 1);
725 	if (!relaname) {
726 		perror("malloc");
727 		return NULL;
728 	}
729 	strcpy(relaname, ".rela");
730 	strcat(relaname, base->name);
731 
732 	sec = elf_create_section(elf, relaname, sizeof(GElf_Rela), 0);
733 	free(relaname);
734 	if (!sec)
735 		return NULL;
736 
737 	base->rela = sec;
738 	sec->base = base;
739 
740 	sec->sh.sh_type = SHT_RELA;
741 	sec->sh.sh_addralign = 8;
742 	sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
743 	sec->sh.sh_info = base->idx;
744 	sec->sh.sh_flags = SHF_INFO_LINK;
745 
746 	return sec;
747 }
748 
749 int elf_rebuild_rela_section(struct section *sec)
750 {
751 	struct rela *rela;
752 	int nr, idx = 0, size;
753 	GElf_Rela *relas;
754 
755 	nr = 0;
756 	list_for_each_entry(rela, &sec->rela_list, list)
757 		nr++;
758 
759 	size = nr * sizeof(*relas);
760 	relas = malloc(size);
761 	if (!relas) {
762 		perror("malloc");
763 		return -1;
764 	}
765 
766 	sec->data->d_buf = relas;
767 	sec->data->d_size = size;
768 
769 	sec->sh.sh_size = size;
770 
771 	idx = 0;
772 	list_for_each_entry(rela, &sec->rela_list, list) {
773 		relas[idx].r_offset = rela->offset;
774 		relas[idx].r_addend = rela->addend;
775 		relas[idx].r_info = GELF_R_INFO(rela->sym->idx, rela->type);
776 		idx++;
777 	}
778 
779 	return 0;
780 }
781 
782 int elf_write(const struct elf *elf)
783 {
784 	struct section *sec;
785 	Elf_Scn *s;
786 
787 	/* Update section headers for changed sections: */
788 	list_for_each_entry(sec, &elf->sections, list) {
789 		if (sec->changed) {
790 			s = elf_getscn(elf->elf, sec->idx);
791 			if (!s) {
792 				WARN_ELF("elf_getscn");
793 				return -1;
794 			}
795 			if (!gelf_update_shdr(s, &sec->sh)) {
796 				WARN_ELF("gelf_update_shdr");
797 				return -1;
798 			}
799 		}
800 	}
801 
802 	/* Make sure the new section header entries get updated properly. */
803 	elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
804 
805 	/* Write all changes to the file. */
806 	if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
807 		WARN_ELF("elf_update");
808 		return -1;
809 	}
810 
811 	return 0;
812 }
813 
814 void elf_close(struct elf *elf)
815 {
816 	struct section *sec, *tmpsec;
817 	struct symbol *sym, *tmpsym;
818 	struct rela *rela, *tmprela;
819 
820 	if (elf->elf)
821 		elf_end(elf->elf);
822 
823 	if (elf->fd > 0)
824 		close(elf->fd);
825 
826 	list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) {
827 		list_for_each_entry_safe(sym, tmpsym, &sec->symbol_list, list) {
828 			list_del(&sym->list);
829 			hash_del(&sym->hash);
830 			free(sym);
831 		}
832 		list_for_each_entry_safe(rela, tmprela, &sec->rela_list, list) {
833 			list_del(&rela->list);
834 			hash_del(&rela->hash);
835 			free(rela);
836 		}
837 		list_del(&sec->list);
838 		free(sec);
839 	}
840 
841 	free(elf);
842 }
843