3  * elf.c - ELF access library
20 #include "elf.h"
130 struct section *find_section_by_name(const struct elf *elf, const char *name)  in find_section_by_name()  argument
134 	elf_hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name))  in find_section_by_name()
141 static struct section *find_section_by_index(struct elf *elf,  in find_section_by_index()  argument
146 	elf_hash_for_each_possible(elf->section_hash, sec, hash, idx)  in find_section_by_index()
153 static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)  in find_symbol_by_index()  argument
157 	elf_hash_for_each_possible(elf->symbol_hash, sym, hash, idx)  in find_symbol_by_index()
220 struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)  in find_symbol_by_name()  argument
224 	elf_hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name))  in find_symbol_by_name()
231 struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,  in find_reloc_by_dest_range()  argument
243 		elf_hash_for_each_possible(elf->reloc_hash, reloc, hash,  in find_reloc_by_dest_range()
260 struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset)  in find_reloc_by_dest()  argument
262 	return find_reloc_by_dest_range(elf, sec, offset, 1);  in find_reloc_by_dest()
265 static int read_sections(struct elf *elf)  in read_sections()  argument
272 	if (elf_getshdrnum(elf->elf, &sections_nr)) {  in read_sections()
277 	if (elf_getshdrstrndx(elf->elf, &shstrndx)) {  in read_sections()
293 		s = elf_getscn(elf->elf, i);  in read_sections()
306 		sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name);  in read_sections()
327 		list_add_tail(&sec->list, &elf->sections);  in read_sections()
328 		elf_hash_add(elf->section_hash, &sec->hash, sec->idx);  in read_sections()
329 		elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));  in read_sections()
336 	if (elf_nextscn(elf->elf, s)) {  in read_sections()
344 static void elf_add_symbol(struct elf *elf, struct symbol *sym)  in elf_add_symbol()  argument
364 	elf_hash_add(elf->symbol_hash, &sym->hash, sym->idx);  in elf_add_symbol()
365 	elf_hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name));  in elf_add_symbol()
375 static int read_symbols(struct elf *elf)  in read_symbols()  argument
384 	symtab = find_section_by_name(elf, ".symtab");  in read_symbols()
393 	symtab_shndx = find_section_by_name(elf, ".symtab_shndx");  in read_symbols()
415 		sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,  in read_symbols()
428 			sym->sec = find_section_by_index(elf, shndx);  in read_symbols()
439 			sym->sec = find_section_by_index(elf, 0);  in read_symbols()
441 		elf_add_symbol(elf, sym);  in read_symbols()
448 	list_for_each_entry(sec, &elf->sections, list) {  in read_symbols()
474 			pfunc = find_symbol_by_name(elf, pname);  in read_symbols()
508 static struct section *elf_create_reloc_section(struct elf *elf,
512 int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,  in elf_add_reloc()  argument
517 	if (!sec->reloc && !elf_create_reloc_section(elf, sec, SHT_RELA))  in elf_add_reloc()
534 	elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));  in elf_add_reloc()
546 static void elf_dirty_reloc_sym(struct elf *elf, struct symbol *sym)  in elf_dirty_reloc_sym()  argument
550 	list_for_each_entry(sec, &elf->sections, list) {  in elf_dirty_reloc_sym()
573 static int elf_update_symbol(struct elf *elf, struct section *symtab,  in elf_update_symbol()  argument
587 	s = elf_getscn(elf->elf, symtab->idx);  in elf_update_symbol()
594 		t = elf_getscn(elf->elf, symtab_shndx->idx);  in elf_update_symbol()
692 elf_create_section_symbol(struct elf *elf, struct section *sec)  in elf_create_section_symbol()  argument
698 	symtab = find_section_by_name(elf, ".symtab");  in elf_create_section_symbol()
700 		symtab_shndx = find_section_by_name(elf, ".symtab_shndx");  in elf_create_section_symbol()
727 	old = find_symbol_by_index(elf, first_non_local);  in elf_create_section_symbol()
732 		elf_hash_add(elf->symbol_hash, &old->hash, old->idx);  in elf_create_section_symbol()
734 		elf_dirty_reloc_sym(elf, old);  in elf_create_section_symbol()
736 		if (elf_update_symbol(elf, symtab, symtab_shndx, old)) {  in elf_create_section_symbol()
745 	if (elf_update_symbol(elf, symtab, symtab_shndx, sym)) {  in elf_create_section_symbol()
755 	elf_add_symbol(elf, sym);  in elf_create_section_symbol()
760 int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,  in elf_add_reloc_to_insn()  argument
774 		sym = elf_create_section_symbol(elf, insn_sec);  in elf_add_reloc_to_insn()
781 	return elf_add_reloc(elf, sec, offset, type, sym, addend);  in elf_add_reloc_to_insn()
810 static int read_relocs(struct elf *elf)  in read_relocs()  argument
818 	list_for_each_entry(sec, &elf->sections, list) {  in read_relocs()
823 		sec->base = find_section_by_index(elf, sec->sh.sh_info);  in read_relocs()
854 			reloc->sym = find_symbol_by_index(elf, symndx);  in read_relocs()
862 			elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));  in read_relocs()
878 struct elf *elf_open_read(const char *name, int flags)  in elf_open_read()
880 	struct elf *elf;  in elf_open_read()  local
885 	elf = malloc(sizeof(*elf));  in elf_open_read()
886 	if (!elf) {  in elf_open_read()
890 	memset(elf, 0, offsetof(struct elf, sections));  in elf_open_read()
892 	INIT_LIST_HEAD(&elf->sections);  in elf_open_read()
894 	elf_hash_init(elf->symbol_hash);  in elf_open_read()
895 	elf_hash_init(elf->symbol_name_hash);  in elf_open_read()
896 	elf_hash_init(elf->section_hash);  in elf_open_read()
897 	elf_hash_init(elf->section_name_hash);  in elf_open_read()
898 	elf_hash_init(elf->reloc_hash);  in elf_open_read()
900 	elf->fd = open(name, flags);  in elf_open_read()
901 	if (elf->fd == -1) {  in elf_open_read()
914 	elf->elf = elf_begin(elf->fd, cmd, NULL);  in elf_open_read()
915 	if (!elf->elf) {  in elf_open_read()
920 	if (!gelf_getehdr(elf->elf, &elf->ehdr)) {  in elf_open_read()
925 	if (read_sections(elf))  in elf_open_read()
928 	if (read_symbols(elf))  in elf_open_read()
931 	if (read_relocs(elf))  in elf_open_read()
934 	return elf;  in elf_open_read()
937 	elf_close(elf);  in elf_open_read()
941 static int elf_add_string(struct elf *elf, struct section *strtab, char *str)  in elf_add_string()  argument
948 		strtab = find_section_by_name(elf, ".strtab");  in elf_add_string()
954 	s = elf_getscn(elf->elf, strtab->idx);  in elf_add_string()
978 struct section *elf_create_section(struct elf *elf, const char *name,  in elf_create_section()  argument
995 	s = elf_newscn(elf->elf);  in elf_create_section()
1041 	shstrtab = find_section_by_name(elf, ".shstrtab");  in elf_create_section()
1043 		shstrtab = find_section_by_name(elf, ".strtab");  in elf_create_section()
1048 	sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);  in elf_create_section()
1052 	list_add_tail(&sec->list, &elf->sections);  in elf_create_section()
1053 	elf_hash_add(elf->section_hash, &sec->hash, sec->idx);  in elf_create_section()
1054 	elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));  in elf_create_section()
1056 	elf->changed = true;  in elf_create_section()
1061 static struct section *elf_create_rel_reloc_section(struct elf *elf, struct section *base)  in elf_create_rel_reloc_section()  argument
1074 	sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rel), 0);  in elf_create_rel_reloc_section()
1084 	sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;  in elf_create_rel_reloc_section()
1091 static struct section *elf_create_rela_reloc_section(struct elf *elf, struct section *base)  in elf_create_rela_reloc_section()  argument
1104 	sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0);  in elf_create_rela_reloc_section()
1114 	sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;  in elf_create_rela_reloc_section()
1121 static struct section *elf_create_reloc_section(struct elf *elf,  in elf_create_reloc_section()  argument
1126 	case SHT_REL:  return elf_create_rel_reloc_section(elf, base);  in elf_create_reloc_section()
1127 	case SHT_RELA: return elf_create_rela_reloc_section(elf, base);  in elf_create_reloc_section()
1191 static int elf_rebuild_reloc_section(struct elf *elf, struct section *sec)  in elf_rebuild_reloc_section()  argument
1207 int elf_write_insn(struct elf *elf, struct section *sec,  in elf_write_insn()  argument
1221 	elf->changed = true;  in elf_write_insn()
1226 int elf_write_reloc(struct elf *elf, struct reloc *reloc)  in elf_write_reloc()  argument
1249 	elf->changed = true;  in elf_write_reloc()
1254 int elf_write(struct elf *elf)  in elf_write()  argument
1260 	list_for_each_entry(sec, &elf->sections, list) {  in elf_write()
1263 			    elf_rebuild_reloc_section(elf, sec)) {  in elf_write()
1268 			s = elf_getscn(elf->elf, sec->idx);  in elf_write()
1279 			elf->changed = true;  in elf_write()
1284 	elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);  in elf_write()
1287 	if (elf_update(elf->elf, ELF_C_WRITE) < 0) {  in elf_write()
1292 	elf->changed = false;  in elf_write()
1297 void elf_close(struct elf *elf)  in elf_close()  argument
1303 	if (elf->elf)  in elf_close()
1304 		elf_end(elf->elf);  in elf_close()
1306 	if (elf->fd > 0)  in elf_close()
1307 		close(elf->fd);  in elf_close()
1309 	list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) {  in elf_close()
1324 	free(elf);  in elf_close()