1442f04c3SJosh Poimboeuf /* 2442f04c3SJosh Poimboeuf * elf.c - ELF access library 3442f04c3SJosh Poimboeuf * 4442f04c3SJosh Poimboeuf * Adapted from kpatch (https://github.com/dynup/kpatch): 5442f04c3SJosh Poimboeuf * Copyright (C) 2013-2015 Josh Poimboeuf <jpoimboe@redhat.com> 6442f04c3SJosh Poimboeuf * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com> 7442f04c3SJosh Poimboeuf * 8442f04c3SJosh Poimboeuf * This program is free software; you can redistribute it and/or 9442f04c3SJosh Poimboeuf * modify it under the terms of the GNU General Public License 10442f04c3SJosh Poimboeuf * as published by the Free Software Foundation; either version 2 11442f04c3SJosh Poimboeuf * of the License, or (at your option) any later version. 12442f04c3SJosh Poimboeuf * 13442f04c3SJosh Poimboeuf * This program is distributed in the hope that it will be useful, 14442f04c3SJosh Poimboeuf * but WITHOUT ANY WARRANTY; without even the implied warranty of 15442f04c3SJosh Poimboeuf * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16442f04c3SJosh Poimboeuf * GNU General Public License for more details. 17442f04c3SJosh Poimboeuf * 18442f04c3SJosh Poimboeuf * You should have received a copy of the GNU General Public License 19442f04c3SJosh Poimboeuf * along with this program; if not, see <http://www.gnu.org/licenses/>. 20442f04c3SJosh Poimboeuf */ 21442f04c3SJosh Poimboeuf 22442f04c3SJosh Poimboeuf #include <sys/types.h> 23442f04c3SJosh Poimboeuf #include <sys/stat.h> 24442f04c3SJosh Poimboeuf #include <fcntl.h> 25442f04c3SJosh Poimboeuf #include <stdio.h> 26442f04c3SJosh Poimboeuf #include <stdlib.h> 27442f04c3SJosh Poimboeuf #include <string.h> 28442f04c3SJosh Poimboeuf #include <unistd.h> 29385d11b1SJosh Poimboeuf #include <errno.h> 30442f04c3SJosh Poimboeuf 31442f04c3SJosh Poimboeuf #include "elf.h" 32442f04c3SJosh Poimboeuf #include "warn.h" 33442f04c3SJosh Poimboeuf 34442f04c3SJosh Poimboeuf struct section *find_section_by_name(struct elf *elf, const char *name) 35442f04c3SJosh Poimboeuf { 36442f04c3SJosh Poimboeuf struct section *sec; 37442f04c3SJosh Poimboeuf 38442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) 39442f04c3SJosh Poimboeuf if (!strcmp(sec->name, name)) 40442f04c3SJosh Poimboeuf return sec; 41442f04c3SJosh Poimboeuf 42442f04c3SJosh Poimboeuf return NULL; 43442f04c3SJosh Poimboeuf } 44442f04c3SJosh Poimboeuf 45442f04c3SJosh Poimboeuf static struct section *find_section_by_index(struct elf *elf, 46442f04c3SJosh Poimboeuf unsigned int idx) 47442f04c3SJosh Poimboeuf { 48442f04c3SJosh Poimboeuf struct section *sec; 49442f04c3SJosh Poimboeuf 50442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) 51442f04c3SJosh Poimboeuf if (sec->idx == idx) 52442f04c3SJosh Poimboeuf return sec; 53442f04c3SJosh Poimboeuf 54442f04c3SJosh Poimboeuf return NULL; 55442f04c3SJosh Poimboeuf } 56442f04c3SJosh Poimboeuf 57442f04c3SJosh Poimboeuf static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx) 58442f04c3SJosh Poimboeuf { 59442f04c3SJosh Poimboeuf struct section *sec; 60442f04c3SJosh Poimboeuf struct symbol *sym; 61442f04c3SJosh Poimboeuf 62442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) 63042ba73fSJosh Poimboeuf hash_for_each_possible(sec->symbol_hash, sym, hash, idx) 64442f04c3SJosh Poimboeuf if (sym->idx == idx) 65442f04c3SJosh Poimboeuf return sym; 66442f04c3SJosh Poimboeuf 67442f04c3SJosh Poimboeuf return NULL; 68442f04c3SJosh Poimboeuf } 69442f04c3SJosh Poimboeuf 70442f04c3SJosh Poimboeuf struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset) 71442f04c3SJosh Poimboeuf { 72442f04c3SJosh Poimboeuf struct symbol *sym; 73442f04c3SJosh Poimboeuf 74a196e171SJosh Poimboeuf list_for_each_entry(sym, &sec->symbol_list, list) 75442f04c3SJosh Poimboeuf if (sym->type != STT_SECTION && 76442f04c3SJosh Poimboeuf sym->offset == offset) 77442f04c3SJosh Poimboeuf return sym; 78442f04c3SJosh Poimboeuf 79442f04c3SJosh Poimboeuf return NULL; 80442f04c3SJosh Poimboeuf } 81442f04c3SJosh Poimboeuf 825c51f4aeSJosh Poimboeuf struct symbol *find_symbol_containing(struct section *sec, unsigned long offset) 835c51f4aeSJosh Poimboeuf { 845c51f4aeSJosh Poimboeuf struct symbol *sym; 855c51f4aeSJosh Poimboeuf 865c51f4aeSJosh Poimboeuf list_for_each_entry(sym, &sec->symbol_list, list) 875c51f4aeSJosh Poimboeuf if (sym->type != STT_SECTION && 885c51f4aeSJosh Poimboeuf offset >= sym->offset && offset < sym->offset + sym->len) 895c51f4aeSJosh Poimboeuf return sym; 905c51f4aeSJosh Poimboeuf 915c51f4aeSJosh Poimboeuf return NULL; 925c51f4aeSJosh Poimboeuf } 935c51f4aeSJosh Poimboeuf 94442f04c3SJosh Poimboeuf struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset, 95442f04c3SJosh Poimboeuf unsigned int len) 96442f04c3SJosh Poimboeuf { 97442f04c3SJosh Poimboeuf struct rela *rela; 98042ba73fSJosh Poimboeuf unsigned long o; 99442f04c3SJosh Poimboeuf 100442f04c3SJosh Poimboeuf if (!sec->rela) 101442f04c3SJosh Poimboeuf return NULL; 102442f04c3SJosh Poimboeuf 103042ba73fSJosh Poimboeuf for (o = offset; o < offset + len; o++) 104042ba73fSJosh Poimboeuf hash_for_each_possible(sec->rela->rela_hash, rela, hash, o) 105042ba73fSJosh Poimboeuf if (rela->offset == o) 106442f04c3SJosh Poimboeuf return rela; 107442f04c3SJosh Poimboeuf 108442f04c3SJosh Poimboeuf return NULL; 109442f04c3SJosh Poimboeuf } 110442f04c3SJosh Poimboeuf 111442f04c3SJosh Poimboeuf struct rela *find_rela_by_dest(struct section *sec, unsigned long offset) 112442f04c3SJosh Poimboeuf { 113442f04c3SJosh Poimboeuf return find_rela_by_dest_range(sec, offset, 1); 114442f04c3SJosh Poimboeuf } 115442f04c3SJosh Poimboeuf 116442f04c3SJosh Poimboeuf struct symbol *find_containing_func(struct section *sec, unsigned long offset) 117442f04c3SJosh Poimboeuf { 118442f04c3SJosh Poimboeuf struct symbol *func; 119442f04c3SJosh Poimboeuf 120a196e171SJosh Poimboeuf list_for_each_entry(func, &sec->symbol_list, list) 121442f04c3SJosh Poimboeuf if (func->type == STT_FUNC && offset >= func->offset && 122442f04c3SJosh Poimboeuf offset < func->offset + func->len) 123442f04c3SJosh Poimboeuf return func; 124442f04c3SJosh Poimboeuf 125442f04c3SJosh Poimboeuf return NULL; 126442f04c3SJosh Poimboeuf } 127442f04c3SJosh Poimboeuf 128442f04c3SJosh Poimboeuf static int read_sections(struct elf *elf) 129442f04c3SJosh Poimboeuf { 130442f04c3SJosh Poimboeuf Elf_Scn *s = NULL; 131442f04c3SJosh Poimboeuf struct section *sec; 132442f04c3SJosh Poimboeuf size_t shstrndx, sections_nr; 133442f04c3SJosh Poimboeuf int i; 134442f04c3SJosh Poimboeuf 135442f04c3SJosh Poimboeuf if (elf_getshdrnum(elf->elf, §ions_nr)) { 136baa41469SJosh Poimboeuf WARN_ELF("elf_getshdrnum"); 137442f04c3SJosh Poimboeuf return -1; 138442f04c3SJosh Poimboeuf } 139442f04c3SJosh Poimboeuf 140442f04c3SJosh Poimboeuf if (elf_getshdrstrndx(elf->elf, &shstrndx)) { 141baa41469SJosh Poimboeuf WARN_ELF("elf_getshdrstrndx"); 142442f04c3SJosh Poimboeuf return -1; 143442f04c3SJosh Poimboeuf } 144442f04c3SJosh Poimboeuf 145442f04c3SJosh Poimboeuf for (i = 0; i < sections_nr; i++) { 146442f04c3SJosh Poimboeuf sec = malloc(sizeof(*sec)); 147442f04c3SJosh Poimboeuf if (!sec) { 148442f04c3SJosh Poimboeuf perror("malloc"); 149442f04c3SJosh Poimboeuf return -1; 150442f04c3SJosh Poimboeuf } 151442f04c3SJosh Poimboeuf memset(sec, 0, sizeof(*sec)); 152442f04c3SJosh Poimboeuf 153a196e171SJosh Poimboeuf INIT_LIST_HEAD(&sec->symbol_list); 154a196e171SJosh Poimboeuf INIT_LIST_HEAD(&sec->rela_list); 155042ba73fSJosh Poimboeuf hash_init(sec->rela_hash); 156042ba73fSJosh Poimboeuf hash_init(sec->symbol_hash); 157442f04c3SJosh Poimboeuf 158442f04c3SJosh Poimboeuf list_add_tail(&sec->list, &elf->sections); 159442f04c3SJosh Poimboeuf 160442f04c3SJosh Poimboeuf s = elf_getscn(elf->elf, i); 161442f04c3SJosh Poimboeuf if (!s) { 162baa41469SJosh Poimboeuf WARN_ELF("elf_getscn"); 163442f04c3SJosh Poimboeuf return -1; 164442f04c3SJosh Poimboeuf } 165442f04c3SJosh Poimboeuf 166442f04c3SJosh Poimboeuf sec->idx = elf_ndxscn(s); 167442f04c3SJosh Poimboeuf 168442f04c3SJosh Poimboeuf if (!gelf_getshdr(s, &sec->sh)) { 169baa41469SJosh Poimboeuf WARN_ELF("gelf_getshdr"); 170442f04c3SJosh Poimboeuf return -1; 171442f04c3SJosh Poimboeuf } 172442f04c3SJosh Poimboeuf 173442f04c3SJosh Poimboeuf sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name); 174442f04c3SJosh Poimboeuf if (!sec->name) { 175baa41469SJosh Poimboeuf WARN_ELF("elf_strptr"); 176442f04c3SJosh Poimboeuf return -1; 177442f04c3SJosh Poimboeuf } 178442f04c3SJosh Poimboeuf 179df968c93SPetr Vandrovec if (sec->sh.sh_size != 0) { 180baa41469SJosh Poimboeuf sec->data = elf_getdata(s, NULL); 181baa41469SJosh Poimboeuf if (!sec->data) { 182baa41469SJosh Poimboeuf WARN_ELF("elf_getdata"); 183442f04c3SJosh Poimboeuf return -1; 184442f04c3SJosh Poimboeuf } 185baa41469SJosh Poimboeuf if (sec->data->d_off != 0 || 186baa41469SJosh Poimboeuf sec->data->d_size != sec->sh.sh_size) { 187df968c93SPetr Vandrovec WARN("unexpected data attributes for %s", 188df968c93SPetr Vandrovec sec->name); 189442f04c3SJosh Poimboeuf return -1; 190442f04c3SJosh Poimboeuf } 191df968c93SPetr Vandrovec } 192df968c93SPetr Vandrovec sec->len = sec->sh.sh_size; 193442f04c3SJosh Poimboeuf } 194442f04c3SJosh Poimboeuf 195442f04c3SJosh Poimboeuf /* sanity check, one more call to elf_nextscn() should return NULL */ 196442f04c3SJosh Poimboeuf if (elf_nextscn(elf->elf, s)) { 197442f04c3SJosh Poimboeuf WARN("section entry mismatch"); 198442f04c3SJosh Poimboeuf return -1; 199442f04c3SJosh Poimboeuf } 200442f04c3SJosh Poimboeuf 201442f04c3SJosh Poimboeuf return 0; 202442f04c3SJosh Poimboeuf } 203442f04c3SJosh Poimboeuf 204442f04c3SJosh Poimboeuf static int read_symbols(struct elf *elf) 205442f04c3SJosh Poimboeuf { 206442f04c3SJosh Poimboeuf struct section *symtab; 207442f04c3SJosh Poimboeuf struct symbol *sym; 208442f04c3SJosh Poimboeuf struct list_head *entry, *tmp; 209442f04c3SJosh Poimboeuf int symbols_nr, i; 210442f04c3SJosh Poimboeuf 211442f04c3SJosh Poimboeuf symtab = find_section_by_name(elf, ".symtab"); 212442f04c3SJosh Poimboeuf if (!symtab) { 213442f04c3SJosh Poimboeuf WARN("missing symbol table"); 214442f04c3SJosh Poimboeuf return -1; 215442f04c3SJosh Poimboeuf } 216442f04c3SJosh Poimboeuf 217442f04c3SJosh Poimboeuf symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize; 218442f04c3SJosh Poimboeuf 219442f04c3SJosh Poimboeuf for (i = 0; i < symbols_nr; i++) { 220442f04c3SJosh Poimboeuf sym = malloc(sizeof(*sym)); 221442f04c3SJosh Poimboeuf if (!sym) { 222442f04c3SJosh Poimboeuf perror("malloc"); 223442f04c3SJosh Poimboeuf return -1; 224442f04c3SJosh Poimboeuf } 225442f04c3SJosh Poimboeuf memset(sym, 0, sizeof(*sym)); 226442f04c3SJosh Poimboeuf 227442f04c3SJosh Poimboeuf sym->idx = i; 228442f04c3SJosh Poimboeuf 229baa41469SJosh Poimboeuf if (!gelf_getsym(symtab->data, i, &sym->sym)) { 230baa41469SJosh Poimboeuf WARN_ELF("gelf_getsym"); 231442f04c3SJosh Poimboeuf goto err; 232442f04c3SJosh Poimboeuf } 233442f04c3SJosh Poimboeuf 234442f04c3SJosh Poimboeuf sym->name = elf_strptr(elf->elf, symtab->sh.sh_link, 235442f04c3SJosh Poimboeuf sym->sym.st_name); 236442f04c3SJosh Poimboeuf if (!sym->name) { 237baa41469SJosh Poimboeuf WARN_ELF("elf_strptr"); 238442f04c3SJosh Poimboeuf goto err; 239442f04c3SJosh Poimboeuf } 240442f04c3SJosh Poimboeuf 241442f04c3SJosh Poimboeuf sym->type = GELF_ST_TYPE(sym->sym.st_info); 242442f04c3SJosh Poimboeuf sym->bind = GELF_ST_BIND(sym->sym.st_info); 243442f04c3SJosh Poimboeuf 244442f04c3SJosh Poimboeuf if (sym->sym.st_shndx > SHN_UNDEF && 245442f04c3SJosh Poimboeuf sym->sym.st_shndx < SHN_LORESERVE) { 246442f04c3SJosh Poimboeuf sym->sec = find_section_by_index(elf, 247442f04c3SJosh Poimboeuf sym->sym.st_shndx); 248442f04c3SJosh Poimboeuf if (!sym->sec) { 249442f04c3SJosh Poimboeuf WARN("couldn't find section for symbol %s", 250442f04c3SJosh Poimboeuf sym->name); 251442f04c3SJosh Poimboeuf goto err; 252442f04c3SJosh Poimboeuf } 253442f04c3SJosh Poimboeuf if (sym->type == STT_SECTION) { 254442f04c3SJosh Poimboeuf sym->name = sym->sec->name; 255442f04c3SJosh Poimboeuf sym->sec->sym = sym; 256442f04c3SJosh Poimboeuf } 257442f04c3SJosh Poimboeuf } else 258442f04c3SJosh Poimboeuf sym->sec = find_section_by_index(elf, 0); 259442f04c3SJosh Poimboeuf 260442f04c3SJosh Poimboeuf sym->offset = sym->sym.st_value; 261442f04c3SJosh Poimboeuf sym->len = sym->sym.st_size; 262442f04c3SJosh Poimboeuf 263442f04c3SJosh Poimboeuf /* sorted insert into a per-section list */ 264a196e171SJosh Poimboeuf entry = &sym->sec->symbol_list; 265a196e171SJosh Poimboeuf list_for_each_prev(tmp, &sym->sec->symbol_list) { 266442f04c3SJosh Poimboeuf struct symbol *s; 267442f04c3SJosh Poimboeuf 268442f04c3SJosh Poimboeuf s = list_entry(tmp, struct symbol, list); 269442f04c3SJosh Poimboeuf 270442f04c3SJosh Poimboeuf if (sym->offset > s->offset) { 271442f04c3SJosh Poimboeuf entry = tmp; 272442f04c3SJosh Poimboeuf break; 273442f04c3SJosh Poimboeuf } 274442f04c3SJosh Poimboeuf 275442f04c3SJosh Poimboeuf if (sym->offset == s->offset && sym->len >= s->len) { 276442f04c3SJosh Poimboeuf entry = tmp; 277442f04c3SJosh Poimboeuf break; 278442f04c3SJosh Poimboeuf } 279442f04c3SJosh Poimboeuf } 280442f04c3SJosh Poimboeuf list_add(&sym->list, entry); 281042ba73fSJosh Poimboeuf hash_add(sym->sec->symbol_hash, &sym->hash, sym->idx); 282442f04c3SJosh Poimboeuf } 283442f04c3SJosh Poimboeuf 284442f04c3SJosh Poimboeuf return 0; 285442f04c3SJosh Poimboeuf 286442f04c3SJosh Poimboeuf err: 287442f04c3SJosh Poimboeuf free(sym); 288442f04c3SJosh Poimboeuf return -1; 289442f04c3SJosh Poimboeuf } 290442f04c3SJosh Poimboeuf 291442f04c3SJosh Poimboeuf static int read_relas(struct elf *elf) 292442f04c3SJosh Poimboeuf { 293442f04c3SJosh Poimboeuf struct section *sec; 294442f04c3SJosh Poimboeuf struct rela *rela; 295442f04c3SJosh Poimboeuf int i; 296442f04c3SJosh Poimboeuf unsigned int symndx; 297442f04c3SJosh Poimboeuf 298442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) { 299442f04c3SJosh Poimboeuf if (sec->sh.sh_type != SHT_RELA) 300442f04c3SJosh Poimboeuf continue; 301442f04c3SJosh Poimboeuf 302442f04c3SJosh Poimboeuf sec->base = find_section_by_name(elf, sec->name + 5); 303442f04c3SJosh Poimboeuf if (!sec->base) { 304442f04c3SJosh Poimboeuf WARN("can't find base section for rela section %s", 305442f04c3SJosh Poimboeuf sec->name); 306442f04c3SJosh Poimboeuf return -1; 307442f04c3SJosh Poimboeuf } 308442f04c3SJosh Poimboeuf 309442f04c3SJosh Poimboeuf sec->base->rela = sec; 310442f04c3SJosh Poimboeuf 311442f04c3SJosh Poimboeuf for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) { 312442f04c3SJosh Poimboeuf rela = malloc(sizeof(*rela)); 313442f04c3SJosh Poimboeuf if (!rela) { 314442f04c3SJosh Poimboeuf perror("malloc"); 315442f04c3SJosh Poimboeuf return -1; 316442f04c3SJosh Poimboeuf } 317442f04c3SJosh Poimboeuf memset(rela, 0, sizeof(*rela)); 318442f04c3SJosh Poimboeuf 319baa41469SJosh Poimboeuf if (!gelf_getrela(sec->data, i, &rela->rela)) { 320baa41469SJosh Poimboeuf WARN_ELF("gelf_getrela"); 321442f04c3SJosh Poimboeuf return -1; 322442f04c3SJosh Poimboeuf } 323442f04c3SJosh Poimboeuf 324442f04c3SJosh Poimboeuf rela->type = GELF_R_TYPE(rela->rela.r_info); 325442f04c3SJosh Poimboeuf rela->addend = rela->rela.r_addend; 326442f04c3SJosh Poimboeuf rela->offset = rela->rela.r_offset; 327442f04c3SJosh Poimboeuf symndx = GELF_R_SYM(rela->rela.r_info); 328442f04c3SJosh Poimboeuf rela->sym = find_symbol_by_index(elf, symndx); 329442f04c3SJosh Poimboeuf if (!rela->sym) { 330442f04c3SJosh Poimboeuf WARN("can't find rela entry symbol %d for %s", 331442f04c3SJosh Poimboeuf symndx, sec->name); 332442f04c3SJosh Poimboeuf return -1; 333442f04c3SJosh Poimboeuf } 334042ba73fSJosh Poimboeuf 335042ba73fSJosh Poimboeuf list_add_tail(&rela->list, &sec->rela_list); 336042ba73fSJosh Poimboeuf hash_add(sec->rela_hash, &rela->hash, rela->offset); 337042ba73fSJosh Poimboeuf 338442f04c3SJosh Poimboeuf } 339442f04c3SJosh Poimboeuf } 340442f04c3SJosh Poimboeuf 341442f04c3SJosh Poimboeuf return 0; 342442f04c3SJosh Poimboeuf } 343442f04c3SJosh Poimboeuf 344627fce14SJosh Poimboeuf struct elf *elf_open(const char *name, int flags) 345442f04c3SJosh Poimboeuf { 346442f04c3SJosh Poimboeuf struct elf *elf; 347627fce14SJosh Poimboeuf Elf_Cmd cmd; 348442f04c3SJosh Poimboeuf 349442f04c3SJosh Poimboeuf elf_version(EV_CURRENT); 350442f04c3SJosh Poimboeuf 351442f04c3SJosh Poimboeuf elf = malloc(sizeof(*elf)); 352442f04c3SJosh Poimboeuf if (!elf) { 353442f04c3SJosh Poimboeuf perror("malloc"); 354442f04c3SJosh Poimboeuf return NULL; 355442f04c3SJosh Poimboeuf } 356442f04c3SJosh Poimboeuf memset(elf, 0, sizeof(*elf)); 357442f04c3SJosh Poimboeuf 358442f04c3SJosh Poimboeuf INIT_LIST_HEAD(&elf->sections); 359442f04c3SJosh Poimboeuf 360627fce14SJosh Poimboeuf elf->fd = open(name, flags); 361442f04c3SJosh Poimboeuf if (elf->fd == -1) { 362385d11b1SJosh Poimboeuf fprintf(stderr, "objtool: Can't open '%s': %s\n", 363385d11b1SJosh Poimboeuf name, strerror(errno)); 364442f04c3SJosh Poimboeuf goto err; 365442f04c3SJosh Poimboeuf } 366442f04c3SJosh Poimboeuf 367627fce14SJosh Poimboeuf if ((flags & O_ACCMODE) == O_RDONLY) 368627fce14SJosh Poimboeuf cmd = ELF_C_READ_MMAP; 369627fce14SJosh Poimboeuf else if ((flags & O_ACCMODE) == O_RDWR) 370627fce14SJosh Poimboeuf cmd = ELF_C_RDWR; 371627fce14SJosh Poimboeuf else /* O_WRONLY */ 372627fce14SJosh Poimboeuf cmd = ELF_C_WRITE; 373627fce14SJosh Poimboeuf 374627fce14SJosh Poimboeuf elf->elf = elf_begin(elf->fd, cmd, NULL); 375442f04c3SJosh Poimboeuf if (!elf->elf) { 376baa41469SJosh Poimboeuf WARN_ELF("elf_begin"); 377442f04c3SJosh Poimboeuf goto err; 378442f04c3SJosh Poimboeuf } 379442f04c3SJosh Poimboeuf 380442f04c3SJosh Poimboeuf if (!gelf_getehdr(elf->elf, &elf->ehdr)) { 381baa41469SJosh Poimboeuf WARN_ELF("gelf_getehdr"); 382442f04c3SJosh Poimboeuf goto err; 383442f04c3SJosh Poimboeuf } 384442f04c3SJosh Poimboeuf 385442f04c3SJosh Poimboeuf if (read_sections(elf)) 386442f04c3SJosh Poimboeuf goto err; 387442f04c3SJosh Poimboeuf 388442f04c3SJosh Poimboeuf if (read_symbols(elf)) 389442f04c3SJosh Poimboeuf goto err; 390442f04c3SJosh Poimboeuf 391442f04c3SJosh Poimboeuf if (read_relas(elf)) 392442f04c3SJosh Poimboeuf goto err; 393442f04c3SJosh Poimboeuf 394442f04c3SJosh Poimboeuf return elf; 395442f04c3SJosh Poimboeuf 396442f04c3SJosh Poimboeuf err: 397442f04c3SJosh Poimboeuf elf_close(elf); 398442f04c3SJosh Poimboeuf return NULL; 399442f04c3SJosh Poimboeuf } 400442f04c3SJosh Poimboeuf 401627fce14SJosh Poimboeuf struct section *elf_create_section(struct elf *elf, const char *name, 402627fce14SJosh Poimboeuf size_t entsize, int nr) 403627fce14SJosh Poimboeuf { 404627fce14SJosh Poimboeuf struct section *sec, *shstrtab; 405627fce14SJosh Poimboeuf size_t size = entsize * nr; 406627fce14SJosh Poimboeuf struct Elf_Scn *s; 407627fce14SJosh Poimboeuf Elf_Data *data; 408627fce14SJosh Poimboeuf 409627fce14SJosh Poimboeuf sec = malloc(sizeof(*sec)); 410627fce14SJosh Poimboeuf if (!sec) { 411627fce14SJosh Poimboeuf perror("malloc"); 412627fce14SJosh Poimboeuf return NULL; 413627fce14SJosh Poimboeuf } 414627fce14SJosh Poimboeuf memset(sec, 0, sizeof(*sec)); 415627fce14SJosh Poimboeuf 416627fce14SJosh Poimboeuf INIT_LIST_HEAD(&sec->symbol_list); 417627fce14SJosh Poimboeuf INIT_LIST_HEAD(&sec->rela_list); 418627fce14SJosh Poimboeuf hash_init(sec->rela_hash); 419627fce14SJosh Poimboeuf hash_init(sec->symbol_hash); 420627fce14SJosh Poimboeuf 421627fce14SJosh Poimboeuf list_add_tail(&sec->list, &elf->sections); 422627fce14SJosh Poimboeuf 423627fce14SJosh Poimboeuf s = elf_newscn(elf->elf); 424627fce14SJosh Poimboeuf if (!s) { 425627fce14SJosh Poimboeuf WARN_ELF("elf_newscn"); 426627fce14SJosh Poimboeuf return NULL; 427627fce14SJosh Poimboeuf } 428627fce14SJosh Poimboeuf 429627fce14SJosh Poimboeuf sec->name = strdup(name); 430627fce14SJosh Poimboeuf if (!sec->name) { 431627fce14SJosh Poimboeuf perror("strdup"); 432627fce14SJosh Poimboeuf return NULL; 433627fce14SJosh Poimboeuf } 434627fce14SJosh Poimboeuf 435627fce14SJosh Poimboeuf sec->idx = elf_ndxscn(s); 436627fce14SJosh Poimboeuf sec->len = size; 437627fce14SJosh Poimboeuf sec->changed = true; 438627fce14SJosh Poimboeuf 439627fce14SJosh Poimboeuf sec->data = elf_newdata(s); 440627fce14SJosh Poimboeuf if (!sec->data) { 441627fce14SJosh Poimboeuf WARN_ELF("elf_newdata"); 442627fce14SJosh Poimboeuf return NULL; 443627fce14SJosh Poimboeuf } 444627fce14SJosh Poimboeuf 445627fce14SJosh Poimboeuf sec->data->d_size = size; 446627fce14SJosh Poimboeuf sec->data->d_align = 1; 447627fce14SJosh Poimboeuf 448627fce14SJosh Poimboeuf if (size) { 449627fce14SJosh Poimboeuf sec->data->d_buf = malloc(size); 450627fce14SJosh Poimboeuf if (!sec->data->d_buf) { 451627fce14SJosh Poimboeuf perror("malloc"); 452627fce14SJosh Poimboeuf return NULL; 453627fce14SJosh Poimboeuf } 454627fce14SJosh Poimboeuf memset(sec->data->d_buf, 0, size); 455627fce14SJosh Poimboeuf } 456627fce14SJosh Poimboeuf 457627fce14SJosh Poimboeuf if (!gelf_getshdr(s, &sec->sh)) { 458627fce14SJosh Poimboeuf WARN_ELF("gelf_getshdr"); 459627fce14SJosh Poimboeuf return NULL; 460627fce14SJosh Poimboeuf } 461627fce14SJosh Poimboeuf 462627fce14SJosh Poimboeuf sec->sh.sh_size = size; 463627fce14SJosh Poimboeuf sec->sh.sh_entsize = entsize; 464627fce14SJosh Poimboeuf sec->sh.sh_type = SHT_PROGBITS; 465627fce14SJosh Poimboeuf sec->sh.sh_addralign = 1; 466627fce14SJosh Poimboeuf sec->sh.sh_flags = SHF_ALLOC; 467627fce14SJosh Poimboeuf 468627fce14SJosh Poimboeuf 469627fce14SJosh Poimboeuf /* Add section name to .shstrtab */ 470627fce14SJosh Poimboeuf shstrtab = find_section_by_name(elf, ".shstrtab"); 471627fce14SJosh Poimboeuf if (!shstrtab) { 472627fce14SJosh Poimboeuf WARN("can't find .shstrtab section"); 473627fce14SJosh Poimboeuf return NULL; 474627fce14SJosh Poimboeuf } 475627fce14SJosh Poimboeuf 476627fce14SJosh Poimboeuf s = elf_getscn(elf->elf, shstrtab->idx); 477627fce14SJosh Poimboeuf if (!s) { 478627fce14SJosh Poimboeuf WARN_ELF("elf_getscn"); 479627fce14SJosh Poimboeuf return NULL; 480627fce14SJosh Poimboeuf } 481627fce14SJosh Poimboeuf 482627fce14SJosh Poimboeuf data = elf_newdata(s); 483627fce14SJosh Poimboeuf if (!data) { 484627fce14SJosh Poimboeuf WARN_ELF("elf_newdata"); 485627fce14SJosh Poimboeuf return NULL; 486627fce14SJosh Poimboeuf } 487627fce14SJosh Poimboeuf 488627fce14SJosh Poimboeuf data->d_buf = sec->name; 489627fce14SJosh Poimboeuf data->d_size = strlen(name) + 1; 490627fce14SJosh Poimboeuf data->d_align = 1; 491627fce14SJosh Poimboeuf 492627fce14SJosh Poimboeuf sec->sh.sh_name = shstrtab->len; 493627fce14SJosh Poimboeuf 494627fce14SJosh Poimboeuf shstrtab->len += strlen(name) + 1; 495627fce14SJosh Poimboeuf shstrtab->changed = true; 496627fce14SJosh Poimboeuf 497627fce14SJosh Poimboeuf return sec; 498627fce14SJosh Poimboeuf } 499627fce14SJosh Poimboeuf 500627fce14SJosh Poimboeuf struct section *elf_create_rela_section(struct elf *elf, struct section *base) 501627fce14SJosh Poimboeuf { 502627fce14SJosh Poimboeuf char *relaname; 503627fce14SJosh Poimboeuf struct section *sec; 504627fce14SJosh Poimboeuf 505627fce14SJosh Poimboeuf relaname = malloc(strlen(base->name) + strlen(".rela") + 1); 506627fce14SJosh Poimboeuf if (!relaname) { 507627fce14SJosh Poimboeuf perror("malloc"); 508627fce14SJosh Poimboeuf return NULL; 509627fce14SJosh Poimboeuf } 510627fce14SJosh Poimboeuf strcpy(relaname, ".rela"); 511627fce14SJosh Poimboeuf strcat(relaname, base->name); 512627fce14SJosh Poimboeuf 513627fce14SJosh Poimboeuf sec = elf_create_section(elf, relaname, sizeof(GElf_Rela), 0); 5140998b7a0SMartin Kepplinger free(relaname); 515627fce14SJosh Poimboeuf if (!sec) 516627fce14SJosh Poimboeuf return NULL; 517627fce14SJosh Poimboeuf 518627fce14SJosh Poimboeuf base->rela = sec; 519627fce14SJosh Poimboeuf sec->base = base; 520627fce14SJosh Poimboeuf 521627fce14SJosh Poimboeuf sec->sh.sh_type = SHT_RELA; 522627fce14SJosh Poimboeuf sec->sh.sh_addralign = 8; 523627fce14SJosh Poimboeuf sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx; 524627fce14SJosh Poimboeuf sec->sh.sh_info = base->idx; 525627fce14SJosh Poimboeuf sec->sh.sh_flags = SHF_INFO_LINK; 526627fce14SJosh Poimboeuf 527627fce14SJosh Poimboeuf return sec; 528627fce14SJosh Poimboeuf } 529627fce14SJosh Poimboeuf 530627fce14SJosh Poimboeuf int elf_rebuild_rela_section(struct section *sec) 531627fce14SJosh Poimboeuf { 532627fce14SJosh Poimboeuf struct rela *rela; 533627fce14SJosh Poimboeuf int nr, idx = 0, size; 534627fce14SJosh Poimboeuf GElf_Rela *relas; 535627fce14SJosh Poimboeuf 536627fce14SJosh Poimboeuf nr = 0; 537627fce14SJosh Poimboeuf list_for_each_entry(rela, &sec->rela_list, list) 538627fce14SJosh Poimboeuf nr++; 539627fce14SJosh Poimboeuf 540627fce14SJosh Poimboeuf size = nr * sizeof(*relas); 541627fce14SJosh Poimboeuf relas = malloc(size); 542627fce14SJosh Poimboeuf if (!relas) { 543627fce14SJosh Poimboeuf perror("malloc"); 544627fce14SJosh Poimboeuf return -1; 545627fce14SJosh Poimboeuf } 546627fce14SJosh Poimboeuf 547627fce14SJosh Poimboeuf sec->data->d_buf = relas; 548627fce14SJosh Poimboeuf sec->data->d_size = size; 549627fce14SJosh Poimboeuf 550627fce14SJosh Poimboeuf sec->sh.sh_size = size; 551627fce14SJosh Poimboeuf 552627fce14SJosh Poimboeuf idx = 0; 553627fce14SJosh Poimboeuf list_for_each_entry(rela, &sec->rela_list, list) { 554627fce14SJosh Poimboeuf relas[idx].r_offset = rela->offset; 555627fce14SJosh Poimboeuf relas[idx].r_addend = rela->addend; 556627fce14SJosh Poimboeuf relas[idx].r_info = GELF_R_INFO(rela->sym->idx, rela->type); 557627fce14SJosh Poimboeuf idx++; 558627fce14SJosh Poimboeuf } 559627fce14SJosh Poimboeuf 560627fce14SJosh Poimboeuf return 0; 561627fce14SJosh Poimboeuf } 562627fce14SJosh Poimboeuf 563627fce14SJosh Poimboeuf int elf_write(struct elf *elf) 564627fce14SJosh Poimboeuf { 565627fce14SJosh Poimboeuf struct section *sec; 566627fce14SJosh Poimboeuf Elf_Scn *s; 567627fce14SJosh Poimboeuf 56897dab2aeSJosh Poimboeuf /* Update section headers for changed sections: */ 569627fce14SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) { 570627fce14SJosh Poimboeuf if (sec->changed) { 571627fce14SJosh Poimboeuf s = elf_getscn(elf->elf, sec->idx); 572627fce14SJosh Poimboeuf if (!s) { 573627fce14SJosh Poimboeuf WARN_ELF("elf_getscn"); 574627fce14SJosh Poimboeuf return -1; 575627fce14SJosh Poimboeuf } 576627fce14SJosh Poimboeuf if (!gelf_update_shdr(s, &sec->sh)) { 577627fce14SJosh Poimboeuf WARN_ELF("gelf_update_shdr"); 578627fce14SJosh Poimboeuf return -1; 579627fce14SJosh Poimboeuf } 580627fce14SJosh Poimboeuf } 581627fce14SJosh Poimboeuf } 582627fce14SJosh Poimboeuf 58397dab2aeSJosh Poimboeuf /* Make sure the new section header entries get updated properly. */ 58497dab2aeSJosh Poimboeuf elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY); 58597dab2aeSJosh Poimboeuf 58697dab2aeSJosh Poimboeuf /* Write all changes to the file. */ 587627fce14SJosh Poimboeuf if (elf_update(elf->elf, ELF_C_WRITE) < 0) { 588627fce14SJosh Poimboeuf WARN_ELF("elf_update"); 589627fce14SJosh Poimboeuf return -1; 590627fce14SJosh Poimboeuf } 591627fce14SJosh Poimboeuf 592627fce14SJosh Poimboeuf return 0; 593627fce14SJosh Poimboeuf } 594627fce14SJosh Poimboeuf 595442f04c3SJosh Poimboeuf void elf_close(struct elf *elf) 596442f04c3SJosh Poimboeuf { 597442f04c3SJosh Poimboeuf struct section *sec, *tmpsec; 598442f04c3SJosh Poimboeuf struct symbol *sym, *tmpsym; 599442f04c3SJosh Poimboeuf struct rela *rela, *tmprela; 600442f04c3SJosh Poimboeuf 601baa41469SJosh Poimboeuf if (elf->elf) 602baa41469SJosh Poimboeuf elf_end(elf->elf); 603baa41469SJosh Poimboeuf 604baa41469SJosh Poimboeuf if (elf->fd > 0) 605baa41469SJosh Poimboeuf close(elf->fd); 606baa41469SJosh Poimboeuf 607442f04c3SJosh Poimboeuf list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) { 608a196e171SJosh Poimboeuf list_for_each_entry_safe(sym, tmpsym, &sec->symbol_list, list) { 609442f04c3SJosh Poimboeuf list_del(&sym->list); 610042ba73fSJosh Poimboeuf hash_del(&sym->hash); 611442f04c3SJosh Poimboeuf free(sym); 612442f04c3SJosh Poimboeuf } 613a196e171SJosh Poimboeuf list_for_each_entry_safe(rela, tmprela, &sec->rela_list, list) { 614442f04c3SJosh Poimboeuf list_del(&rela->list); 615042ba73fSJosh Poimboeuf hash_del(&rela->hash); 616442f04c3SJosh Poimboeuf free(rela); 617442f04c3SJosh Poimboeuf } 618442f04c3SJosh Poimboeuf list_del(&sec->list); 619442f04c3SJosh Poimboeuf free(sec); 620442f04c3SJosh Poimboeuf } 621baa41469SJosh Poimboeuf 622442f04c3SJosh Poimboeuf free(elf); 623442f04c3SJosh Poimboeuf } 624