tools/objtool/elf.c

3  * elf.c - ELF access library
22 #include <objtool/elf.h>
30 #define __elf_table(name)	(elf->name##_hash)
31 #define __elf_bits(name)	(elf->name##_bits)
130 struct section *find_section_by_name(const struct elf *elf, const char *name)
142 static struct section *find_section_by_index(struct elf *elf,
155 static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
254 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
266 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
296 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset)
298 	return find_reloc_by_dest_range(elf, sec, offset, 1);
306 static int read_sections(struct elf *elf)
313 	if (elf_getshdrnum(elf->elf, &sections_nr)) {
318 	if (elf_getshdrstrndx(elf->elf, &shstrndx)) {
327 	elf->section_data = calloc(sections_nr, sizeof(*sec));
328 	if (!elf->section_data) {
333 		sec = &elf->section_data[i];
337 		s = elf_getscn(elf->elf, i);
350 		sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);
370 		list_add_tail(&sec->list, &elf->sections);
375 			elf->num_relocs += sec_num_entries(sec);
380 		printf("section_bits: %d\n", elf->section_bits);
384 	if (elf_nextscn(elf->elf, s)) {
392 static void elf_add_symbol(struct elf *elf, struct symbol *sym)
405 		elf->num_files++;
433 static int read_symbols(struct elf *elf)
442 	symtab = find_section_by_name(elf, ".symtab");
444 		symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
463 	elf->symbol_data = calloc(symbols_nr, sizeof(*sym));
464 	if (!elf->symbol_data) {
469 		sym = &elf->symbol_data[i];
479 		sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
492 			sym->sec = find_section_by_index(elf, shndx);
503 			sym->sec = find_section_by_index(elf, 0);
505 		elf_add_symbol(elf, sym);
510 		printf("symbol_bits: %d\n", elf->symbol_bits);
514 	list_for_each_entry(sec, &elf->sections, list) {
539 			pfunc = find_symbol_by_name(elf, pname);
577 static int elf_update_sym_relocs(struct elf *elf, struct symbol *sym)
582 		set_reloc_sym(elf, reloc, reloc->sym->idx);
595 static int elf_update_symbol(struct elf *elf, struct section *symtab,
609 	s = elf_getscn(elf->elf, symtab->idx);
616 		t = elf_getscn(elf->elf, symtab_shndx->idx);
661 			mark_sec_changed(elf, symtab, true);
676 				mark_sec_changed(elf, symtab_shndx, true);
726 __elf_create_symbol(struct elf *elf, struct symbol *sym)
732 	symtab = find_section_by_name(elf, ".symtab");
734 		symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
750 	old = find_symbol_by_index(elf, first_non_local);
757 		if (elf_update_symbol(elf, symtab, symtab_shndx, old)) {
762 		if (elf_update_sym_relocs(elf, old))
775 	if (elf_update_symbol(elf, symtab, symtab_shndx, sym)) {
781 	mark_sec_changed(elf, symtab, true);
785 		mark_sec_changed(elf, symtab_shndx, true);
792 elf_create_section_symbol(struct elf *elf, struct section *sec)
810 	sym = __elf_create_symbol(elf, sym);
812 		elf_add_symbol(elf, sym);
817 static int elf_add_string(struct elf *elf, struct section *strtab, char *str);
820 elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size)
836 	sym->sym.st_name = elf_add_string(elf, NULL, name);
841 	sym = __elf_create_symbol(elf, sym);
843 		elf_add_symbol(elf, sym);
848 static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
872 	set_reloc_offset(elf, reloc, offset);
873 	set_reloc_sym(elf, reloc, sym->idx);
874 	set_reloc_type(elf, reloc, type);
875 	set_reloc_addend(elf, reloc, addend);
884 struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
906 		sym = elf_create_section_symbol(elf, insn_sec);
913 	return elf_init_reloc(elf, sec->rsec, reloc_idx, offset, sym, addend,
914 			      elf_text_rela_type(elf));
917 struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
929 	return elf_init_reloc(elf, sec->rsec, reloc_idx, offset, sym, addend,
930 			      elf_data_rela_type(elf));
933 static int read_relocs(struct elf *elf)
942 	if (!elf_alloc_hash(reloc, elf->num_relocs))
945 	list_for_each_entry(rsec, &elf->sections, list) {
949 		rsec->base = find_section_by_index(elf, rsec->sh.sh_info);
969 			reloc->sym = sym = find_symbol_by_index(elf, symndx);
987 		printf("num_relocs: %lu\n", elf->num_relocs);
988 		printf("reloc_bits: %d\n", elf->reloc_bits);
994 struct elf *elf_open_read(const char *name, int flags)
996 	struct elf *elf;
1001 	elf = malloc(sizeof(*elf));
1002 	if (!elf) {
1006 	memset(elf, 0, sizeof(*elf));
1008 	INIT_LIST_HEAD(&elf->sections);
1010 	elf->fd = open(name, flags);
1011 	if (elf->fd == -1) {
1024 	elf->elf = elf_begin(elf->fd, cmd, NULL);
1025 	if (!elf->elf) {
1030 	if (!gelf_getehdr(elf->elf, &elf->ehdr)) {
1035 	if (read_sections(elf))
1038 	if (read_symbols(elf))
1041 	if (read_relocs(elf))
1044 	return elf;
1047 	elf_close(elf);
1051 static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
1058 		strtab = find_section_by_name(elf, ".strtab");
1064 	s = elf_getscn(elf->elf, strtab->idx);
1083 	mark_sec_changed(elf, strtab, true);
1088 struct section *elf_create_section(struct elf *elf, const char *name,
1104 	s = elf_newscn(elf->elf);
1148 	shstrtab = find_section_by_name(elf, ".shstrtab");
1150 		shstrtab = find_section_by_name(elf, ".strtab");
1155 	sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);
1159 	list_add_tail(&sec->list, &elf->sections);
1163 	mark_sec_changed(elf, sec, true);
1168 static struct section *elf_create_rela_section(struct elf *elf,
1183 	rsec = elf_create_section(elf, rsec_name, elf_rela_size(elf), reloc_nr);
1190 	rsec->sh.sh_addralign = elf_addr_size(elf);
1191 	rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
1207 struct section *elf_create_section_pair(struct elf *elf, const char *name,
1213 	sec = elf_create_section(elf, name, entsize, nr);
1217 	if (!elf_create_rela_section(elf, sec, reloc_nr))
1223 int elf_write_insn(struct elf *elf, struct section *sec,
1236 	mark_sec_changed(elf, sec, true);
1250 static int elf_truncate_section(struct elf *elf, struct section *sec)
1257 	s = elf_getscn(elf->elf, sec->idx);
1295 int elf_write(struct elf *elf)
1304 	list_for_each_entry(sec, &elf->sections, list) {
1306 			elf_truncate_section(elf, sec);
1309 			s = elf_getscn(elf->elf, sec->idx);
1321 			mark_sec_changed(elf, sec, false);
1326 	elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
1329 	if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
1334 	elf->changed = false;
1339 void elf_close(struct elf *elf)
1341 	if (elf->elf)
1342 		elf_end(elf->elf);
1344 	if (elf->fd > 0)
1345 		close(elf->fd);