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