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> 29442f04c3SJosh Poimboeuf 30442f04c3SJosh Poimboeuf #include "elf.h" 31442f04c3SJosh Poimboeuf #include "warn.h" 32442f04c3SJosh Poimboeuf 33442f04c3SJosh Poimboeuf struct section *find_section_by_name(struct elf *elf, const char *name) 34442f04c3SJosh Poimboeuf { 35442f04c3SJosh Poimboeuf struct section *sec; 36442f04c3SJosh Poimboeuf 37442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) 38442f04c3SJosh Poimboeuf if (!strcmp(sec->name, name)) 39442f04c3SJosh Poimboeuf return sec; 40442f04c3SJosh Poimboeuf 41442f04c3SJosh Poimboeuf return NULL; 42442f04c3SJosh Poimboeuf } 43442f04c3SJosh Poimboeuf 44442f04c3SJosh Poimboeuf static struct section *find_section_by_index(struct elf *elf, 45442f04c3SJosh Poimboeuf unsigned int idx) 46442f04c3SJosh Poimboeuf { 47442f04c3SJosh Poimboeuf struct section *sec; 48442f04c3SJosh Poimboeuf 49442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) 50442f04c3SJosh Poimboeuf if (sec->idx == idx) 51442f04c3SJosh Poimboeuf return sec; 52442f04c3SJosh Poimboeuf 53442f04c3SJosh Poimboeuf return NULL; 54442f04c3SJosh Poimboeuf } 55442f04c3SJosh Poimboeuf 56442f04c3SJosh Poimboeuf static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx) 57442f04c3SJosh Poimboeuf { 58442f04c3SJosh Poimboeuf struct section *sec; 59442f04c3SJosh Poimboeuf struct symbol *sym; 60442f04c3SJosh Poimboeuf 61442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) 62042ba73fSJosh Poimboeuf hash_for_each_possible(sec->symbol_hash, sym, hash, idx) 63442f04c3SJosh Poimboeuf if (sym->idx == idx) 64442f04c3SJosh Poimboeuf return sym; 65442f04c3SJosh Poimboeuf 66442f04c3SJosh Poimboeuf return NULL; 67442f04c3SJosh Poimboeuf } 68442f04c3SJosh Poimboeuf 69442f04c3SJosh Poimboeuf struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset) 70442f04c3SJosh Poimboeuf { 71442f04c3SJosh Poimboeuf struct symbol *sym; 72442f04c3SJosh Poimboeuf 73a196e171SJosh Poimboeuf list_for_each_entry(sym, &sec->symbol_list, list) 74442f04c3SJosh Poimboeuf if (sym->type != STT_SECTION && 75442f04c3SJosh Poimboeuf sym->offset == offset) 76442f04c3SJosh Poimboeuf return sym; 77442f04c3SJosh Poimboeuf 78442f04c3SJosh Poimboeuf return NULL; 79442f04c3SJosh Poimboeuf } 80442f04c3SJosh Poimboeuf 815c51f4aeSJosh Poimboeuf struct symbol *find_symbol_containing(struct section *sec, unsigned long offset) 825c51f4aeSJosh Poimboeuf { 835c51f4aeSJosh Poimboeuf struct symbol *sym; 845c51f4aeSJosh Poimboeuf 855c51f4aeSJosh Poimboeuf list_for_each_entry(sym, &sec->symbol_list, list) 865c51f4aeSJosh Poimboeuf if (sym->type != STT_SECTION && 875c51f4aeSJosh Poimboeuf offset >= sym->offset && offset < sym->offset + sym->len) 885c51f4aeSJosh Poimboeuf return sym; 895c51f4aeSJosh Poimboeuf 905c51f4aeSJosh Poimboeuf return NULL; 915c51f4aeSJosh Poimboeuf } 925c51f4aeSJosh Poimboeuf 93442f04c3SJosh Poimboeuf struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset, 94442f04c3SJosh Poimboeuf unsigned int len) 95442f04c3SJosh Poimboeuf { 96442f04c3SJosh Poimboeuf struct rela *rela; 97042ba73fSJosh Poimboeuf unsigned long o; 98442f04c3SJosh Poimboeuf 99442f04c3SJosh Poimboeuf if (!sec->rela) 100442f04c3SJosh Poimboeuf return NULL; 101442f04c3SJosh Poimboeuf 102042ba73fSJosh Poimboeuf for (o = offset; o < offset + len; o++) 103042ba73fSJosh Poimboeuf hash_for_each_possible(sec->rela->rela_hash, rela, hash, o) 104042ba73fSJosh Poimboeuf if (rela->offset == o) 105442f04c3SJosh Poimboeuf return rela; 106442f04c3SJosh Poimboeuf 107442f04c3SJosh Poimboeuf return NULL; 108442f04c3SJosh Poimboeuf } 109442f04c3SJosh Poimboeuf 110442f04c3SJosh Poimboeuf struct rela *find_rela_by_dest(struct section *sec, unsigned long offset) 111442f04c3SJosh Poimboeuf { 112442f04c3SJosh Poimboeuf return find_rela_by_dest_range(sec, offset, 1); 113442f04c3SJosh Poimboeuf } 114442f04c3SJosh Poimboeuf 115442f04c3SJosh Poimboeuf struct symbol *find_containing_func(struct section *sec, unsigned long offset) 116442f04c3SJosh Poimboeuf { 117442f04c3SJosh Poimboeuf struct symbol *func; 118442f04c3SJosh Poimboeuf 119a196e171SJosh Poimboeuf list_for_each_entry(func, &sec->symbol_list, list) 120442f04c3SJosh Poimboeuf if (func->type == STT_FUNC && offset >= func->offset && 121442f04c3SJosh Poimboeuf offset < func->offset + func->len) 122442f04c3SJosh Poimboeuf return func; 123442f04c3SJosh Poimboeuf 124442f04c3SJosh Poimboeuf return NULL; 125442f04c3SJosh Poimboeuf } 126442f04c3SJosh Poimboeuf 127442f04c3SJosh Poimboeuf static int read_sections(struct elf *elf) 128442f04c3SJosh Poimboeuf { 129442f04c3SJosh Poimboeuf Elf_Scn *s = NULL; 130442f04c3SJosh Poimboeuf struct section *sec; 131442f04c3SJosh Poimboeuf size_t shstrndx, sections_nr; 132442f04c3SJosh Poimboeuf int i; 133442f04c3SJosh Poimboeuf 134442f04c3SJosh Poimboeuf if (elf_getshdrnum(elf->elf, §ions_nr)) { 135baa41469SJosh Poimboeuf WARN_ELF("elf_getshdrnum"); 136442f04c3SJosh Poimboeuf return -1; 137442f04c3SJosh Poimboeuf } 138442f04c3SJosh Poimboeuf 139442f04c3SJosh Poimboeuf if (elf_getshdrstrndx(elf->elf, &shstrndx)) { 140baa41469SJosh Poimboeuf WARN_ELF("elf_getshdrstrndx"); 141442f04c3SJosh Poimboeuf return -1; 142442f04c3SJosh Poimboeuf } 143442f04c3SJosh Poimboeuf 144442f04c3SJosh Poimboeuf for (i = 0; i < sections_nr; i++) { 145442f04c3SJosh Poimboeuf sec = malloc(sizeof(*sec)); 146442f04c3SJosh Poimboeuf if (!sec) { 147442f04c3SJosh Poimboeuf perror("malloc"); 148442f04c3SJosh Poimboeuf return -1; 149442f04c3SJosh Poimboeuf } 150442f04c3SJosh Poimboeuf memset(sec, 0, sizeof(*sec)); 151442f04c3SJosh Poimboeuf 152a196e171SJosh Poimboeuf INIT_LIST_HEAD(&sec->symbol_list); 153a196e171SJosh Poimboeuf INIT_LIST_HEAD(&sec->rela_list); 154042ba73fSJosh Poimboeuf hash_init(sec->rela_hash); 155042ba73fSJosh Poimboeuf hash_init(sec->symbol_hash); 156442f04c3SJosh Poimboeuf 157442f04c3SJosh Poimboeuf list_add_tail(&sec->list, &elf->sections); 158442f04c3SJosh Poimboeuf 159442f04c3SJosh Poimboeuf s = elf_getscn(elf->elf, i); 160442f04c3SJosh Poimboeuf if (!s) { 161baa41469SJosh Poimboeuf WARN_ELF("elf_getscn"); 162442f04c3SJosh Poimboeuf return -1; 163442f04c3SJosh Poimboeuf } 164442f04c3SJosh Poimboeuf 165442f04c3SJosh Poimboeuf sec->idx = elf_ndxscn(s); 166442f04c3SJosh Poimboeuf 167442f04c3SJosh Poimboeuf if (!gelf_getshdr(s, &sec->sh)) { 168baa41469SJosh Poimboeuf WARN_ELF("gelf_getshdr"); 169442f04c3SJosh Poimboeuf return -1; 170442f04c3SJosh Poimboeuf } 171442f04c3SJosh Poimboeuf 172442f04c3SJosh Poimboeuf sec->name = elf_strptr(elf->elf, shstrndx, sec->sh.sh_name); 173442f04c3SJosh Poimboeuf if (!sec->name) { 174baa41469SJosh Poimboeuf WARN_ELF("elf_strptr"); 175442f04c3SJosh Poimboeuf return -1; 176442f04c3SJosh Poimboeuf } 177442f04c3SJosh Poimboeuf 178baa41469SJosh Poimboeuf sec->data = elf_getdata(s, NULL); 179baa41469SJosh Poimboeuf if (!sec->data) { 180baa41469SJosh Poimboeuf WARN_ELF("elf_getdata"); 181442f04c3SJosh Poimboeuf return -1; 182442f04c3SJosh Poimboeuf } 183442f04c3SJosh Poimboeuf 184baa41469SJosh Poimboeuf if (sec->data->d_off != 0 || 185baa41469SJosh Poimboeuf sec->data->d_size != sec->sh.sh_size) { 186442f04c3SJosh Poimboeuf WARN("unexpected data attributes for %s", sec->name); 187442f04c3SJosh Poimboeuf return -1; 188442f04c3SJosh Poimboeuf } 189442f04c3SJosh Poimboeuf 190baa41469SJosh Poimboeuf sec->len = sec->data->d_size; 191442f04c3SJosh Poimboeuf } 192442f04c3SJosh Poimboeuf 193442f04c3SJosh Poimboeuf /* sanity check, one more call to elf_nextscn() should return NULL */ 194442f04c3SJosh Poimboeuf if (elf_nextscn(elf->elf, s)) { 195442f04c3SJosh Poimboeuf WARN("section entry mismatch"); 196442f04c3SJosh Poimboeuf return -1; 197442f04c3SJosh Poimboeuf } 198442f04c3SJosh Poimboeuf 199442f04c3SJosh Poimboeuf return 0; 200442f04c3SJosh Poimboeuf } 201442f04c3SJosh Poimboeuf 202442f04c3SJosh Poimboeuf static int read_symbols(struct elf *elf) 203442f04c3SJosh Poimboeuf { 204442f04c3SJosh Poimboeuf struct section *symtab; 205442f04c3SJosh Poimboeuf struct symbol *sym; 206442f04c3SJosh Poimboeuf struct list_head *entry, *tmp; 207442f04c3SJosh Poimboeuf int symbols_nr, i; 208442f04c3SJosh Poimboeuf 209442f04c3SJosh Poimboeuf symtab = find_section_by_name(elf, ".symtab"); 210442f04c3SJosh Poimboeuf if (!symtab) { 211442f04c3SJosh Poimboeuf WARN("missing symbol table"); 212442f04c3SJosh Poimboeuf return -1; 213442f04c3SJosh Poimboeuf } 214442f04c3SJosh Poimboeuf 215442f04c3SJosh Poimboeuf symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize; 216442f04c3SJosh Poimboeuf 217442f04c3SJosh Poimboeuf for (i = 0; i < symbols_nr; i++) { 218442f04c3SJosh Poimboeuf sym = malloc(sizeof(*sym)); 219442f04c3SJosh Poimboeuf if (!sym) { 220442f04c3SJosh Poimboeuf perror("malloc"); 221442f04c3SJosh Poimboeuf return -1; 222442f04c3SJosh Poimboeuf } 223442f04c3SJosh Poimboeuf memset(sym, 0, sizeof(*sym)); 224442f04c3SJosh Poimboeuf 225442f04c3SJosh Poimboeuf sym->idx = i; 226442f04c3SJosh Poimboeuf 227baa41469SJosh Poimboeuf if (!gelf_getsym(symtab->data, i, &sym->sym)) { 228baa41469SJosh Poimboeuf WARN_ELF("gelf_getsym"); 229442f04c3SJosh Poimboeuf goto err; 230442f04c3SJosh Poimboeuf } 231442f04c3SJosh Poimboeuf 232442f04c3SJosh Poimboeuf sym->name = elf_strptr(elf->elf, symtab->sh.sh_link, 233442f04c3SJosh Poimboeuf sym->sym.st_name); 234442f04c3SJosh Poimboeuf if (!sym->name) { 235baa41469SJosh Poimboeuf WARN_ELF("elf_strptr"); 236442f04c3SJosh Poimboeuf goto err; 237442f04c3SJosh Poimboeuf } 238442f04c3SJosh Poimboeuf 239442f04c3SJosh Poimboeuf sym->type = GELF_ST_TYPE(sym->sym.st_info); 240442f04c3SJosh Poimboeuf sym->bind = GELF_ST_BIND(sym->sym.st_info); 241442f04c3SJosh Poimboeuf 242442f04c3SJosh Poimboeuf if (sym->sym.st_shndx > SHN_UNDEF && 243442f04c3SJosh Poimboeuf sym->sym.st_shndx < SHN_LORESERVE) { 244442f04c3SJosh Poimboeuf sym->sec = find_section_by_index(elf, 245442f04c3SJosh Poimboeuf sym->sym.st_shndx); 246442f04c3SJosh Poimboeuf if (!sym->sec) { 247442f04c3SJosh Poimboeuf WARN("couldn't find section for symbol %s", 248442f04c3SJosh Poimboeuf sym->name); 249442f04c3SJosh Poimboeuf goto err; 250442f04c3SJosh Poimboeuf } 251442f04c3SJosh Poimboeuf if (sym->type == STT_SECTION) { 252442f04c3SJosh Poimboeuf sym->name = sym->sec->name; 253442f04c3SJosh Poimboeuf sym->sec->sym = sym; 254442f04c3SJosh Poimboeuf } 255442f04c3SJosh Poimboeuf } else 256442f04c3SJosh Poimboeuf sym->sec = find_section_by_index(elf, 0); 257442f04c3SJosh Poimboeuf 258442f04c3SJosh Poimboeuf sym->offset = sym->sym.st_value; 259442f04c3SJosh Poimboeuf sym->len = sym->sym.st_size; 260442f04c3SJosh Poimboeuf 261442f04c3SJosh Poimboeuf /* sorted insert into a per-section list */ 262a196e171SJosh Poimboeuf entry = &sym->sec->symbol_list; 263a196e171SJosh Poimboeuf list_for_each_prev(tmp, &sym->sec->symbol_list) { 264442f04c3SJosh Poimboeuf struct symbol *s; 265442f04c3SJosh Poimboeuf 266442f04c3SJosh Poimboeuf s = list_entry(tmp, struct symbol, list); 267442f04c3SJosh Poimboeuf 268442f04c3SJosh Poimboeuf if (sym->offset > s->offset) { 269442f04c3SJosh Poimboeuf entry = tmp; 270442f04c3SJosh Poimboeuf break; 271442f04c3SJosh Poimboeuf } 272442f04c3SJosh Poimboeuf 273442f04c3SJosh Poimboeuf if (sym->offset == s->offset && sym->len >= s->len) { 274442f04c3SJosh Poimboeuf entry = tmp; 275442f04c3SJosh Poimboeuf break; 276442f04c3SJosh Poimboeuf } 277442f04c3SJosh Poimboeuf } 278442f04c3SJosh Poimboeuf list_add(&sym->list, entry); 279042ba73fSJosh Poimboeuf hash_add(sym->sec->symbol_hash, &sym->hash, sym->idx); 280442f04c3SJosh Poimboeuf } 281442f04c3SJosh Poimboeuf 282442f04c3SJosh Poimboeuf return 0; 283442f04c3SJosh Poimboeuf 284442f04c3SJosh Poimboeuf err: 285442f04c3SJosh Poimboeuf free(sym); 286442f04c3SJosh Poimboeuf return -1; 287442f04c3SJosh Poimboeuf } 288442f04c3SJosh Poimboeuf 289442f04c3SJosh Poimboeuf static int read_relas(struct elf *elf) 290442f04c3SJosh Poimboeuf { 291442f04c3SJosh Poimboeuf struct section *sec; 292442f04c3SJosh Poimboeuf struct rela *rela; 293442f04c3SJosh Poimboeuf int i; 294442f04c3SJosh Poimboeuf unsigned int symndx; 295442f04c3SJosh Poimboeuf 296442f04c3SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) { 297442f04c3SJosh Poimboeuf if (sec->sh.sh_type != SHT_RELA) 298442f04c3SJosh Poimboeuf continue; 299442f04c3SJosh Poimboeuf 300442f04c3SJosh Poimboeuf sec->base = find_section_by_name(elf, sec->name + 5); 301442f04c3SJosh Poimboeuf if (!sec->base) { 302442f04c3SJosh Poimboeuf WARN("can't find base section for rela section %s", 303442f04c3SJosh Poimboeuf sec->name); 304442f04c3SJosh Poimboeuf return -1; 305442f04c3SJosh Poimboeuf } 306442f04c3SJosh Poimboeuf 307442f04c3SJosh Poimboeuf sec->base->rela = sec; 308442f04c3SJosh Poimboeuf 309442f04c3SJosh Poimboeuf for (i = 0; i < sec->sh.sh_size / sec->sh.sh_entsize; i++) { 310442f04c3SJosh Poimboeuf rela = malloc(sizeof(*rela)); 311442f04c3SJosh Poimboeuf if (!rela) { 312442f04c3SJosh Poimboeuf perror("malloc"); 313442f04c3SJosh Poimboeuf return -1; 314442f04c3SJosh Poimboeuf } 315442f04c3SJosh Poimboeuf memset(rela, 0, sizeof(*rela)); 316442f04c3SJosh Poimboeuf 317baa41469SJosh Poimboeuf if (!gelf_getrela(sec->data, i, &rela->rela)) { 318baa41469SJosh Poimboeuf WARN_ELF("gelf_getrela"); 319442f04c3SJosh Poimboeuf return -1; 320442f04c3SJosh Poimboeuf } 321442f04c3SJosh Poimboeuf 322442f04c3SJosh Poimboeuf rela->type = GELF_R_TYPE(rela->rela.r_info); 323442f04c3SJosh Poimboeuf rela->addend = rela->rela.r_addend; 324442f04c3SJosh Poimboeuf rela->offset = rela->rela.r_offset; 325442f04c3SJosh Poimboeuf symndx = GELF_R_SYM(rela->rela.r_info); 326442f04c3SJosh Poimboeuf rela->sym = find_symbol_by_index(elf, symndx); 327442f04c3SJosh Poimboeuf if (!rela->sym) { 328442f04c3SJosh Poimboeuf WARN("can't find rela entry symbol %d for %s", 329442f04c3SJosh Poimboeuf symndx, sec->name); 330442f04c3SJosh Poimboeuf return -1; 331442f04c3SJosh Poimboeuf } 332042ba73fSJosh Poimboeuf 333042ba73fSJosh Poimboeuf list_add_tail(&rela->list, &sec->rela_list); 334042ba73fSJosh Poimboeuf hash_add(sec->rela_hash, &rela->hash, rela->offset); 335042ba73fSJosh Poimboeuf 336442f04c3SJosh Poimboeuf } 337442f04c3SJosh Poimboeuf } 338442f04c3SJosh Poimboeuf 339442f04c3SJosh Poimboeuf return 0; 340442f04c3SJosh Poimboeuf } 341442f04c3SJosh Poimboeuf 342627fce14SJosh Poimboeuf struct elf *elf_open(const char *name, int flags) 343442f04c3SJosh Poimboeuf { 344442f04c3SJosh Poimboeuf struct elf *elf; 345627fce14SJosh Poimboeuf Elf_Cmd cmd; 346442f04c3SJosh Poimboeuf 347442f04c3SJosh Poimboeuf elf_version(EV_CURRENT); 348442f04c3SJosh Poimboeuf 349442f04c3SJosh Poimboeuf elf = malloc(sizeof(*elf)); 350442f04c3SJosh Poimboeuf if (!elf) { 351442f04c3SJosh Poimboeuf perror("malloc"); 352442f04c3SJosh Poimboeuf return NULL; 353442f04c3SJosh Poimboeuf } 354442f04c3SJosh Poimboeuf memset(elf, 0, sizeof(*elf)); 355442f04c3SJosh Poimboeuf 356442f04c3SJosh Poimboeuf INIT_LIST_HEAD(&elf->sections); 357442f04c3SJosh Poimboeuf 358627fce14SJosh Poimboeuf elf->fd = open(name, flags); 359442f04c3SJosh Poimboeuf if (elf->fd == -1) { 360442f04c3SJosh Poimboeuf perror("open"); 361442f04c3SJosh Poimboeuf goto err; 362442f04c3SJosh Poimboeuf } 363442f04c3SJosh Poimboeuf 364627fce14SJosh Poimboeuf if ((flags & O_ACCMODE) == O_RDONLY) 365627fce14SJosh Poimboeuf cmd = ELF_C_READ_MMAP; 366627fce14SJosh Poimboeuf else if ((flags & O_ACCMODE) == O_RDWR) 367627fce14SJosh Poimboeuf cmd = ELF_C_RDWR; 368627fce14SJosh Poimboeuf else /* O_WRONLY */ 369627fce14SJosh Poimboeuf cmd = ELF_C_WRITE; 370627fce14SJosh Poimboeuf 371627fce14SJosh Poimboeuf elf->elf = elf_begin(elf->fd, cmd, NULL); 372442f04c3SJosh Poimboeuf if (!elf->elf) { 373baa41469SJosh Poimboeuf WARN_ELF("elf_begin"); 374442f04c3SJosh Poimboeuf goto err; 375442f04c3SJosh Poimboeuf } 376442f04c3SJosh Poimboeuf 377442f04c3SJosh Poimboeuf if (!gelf_getehdr(elf->elf, &elf->ehdr)) { 378baa41469SJosh Poimboeuf WARN_ELF("gelf_getehdr"); 379442f04c3SJosh Poimboeuf goto err; 380442f04c3SJosh Poimboeuf } 381442f04c3SJosh Poimboeuf 382442f04c3SJosh Poimboeuf if (read_sections(elf)) 383442f04c3SJosh Poimboeuf goto err; 384442f04c3SJosh Poimboeuf 385442f04c3SJosh Poimboeuf if (read_symbols(elf)) 386442f04c3SJosh Poimboeuf goto err; 387442f04c3SJosh Poimboeuf 388442f04c3SJosh Poimboeuf if (read_relas(elf)) 389442f04c3SJosh Poimboeuf goto err; 390442f04c3SJosh Poimboeuf 391442f04c3SJosh Poimboeuf return elf; 392442f04c3SJosh Poimboeuf 393442f04c3SJosh Poimboeuf err: 394442f04c3SJosh Poimboeuf elf_close(elf); 395442f04c3SJosh Poimboeuf return NULL; 396442f04c3SJosh Poimboeuf } 397442f04c3SJosh Poimboeuf 398627fce14SJosh Poimboeuf struct section *elf_create_section(struct elf *elf, const char *name, 399627fce14SJosh Poimboeuf size_t entsize, int nr) 400627fce14SJosh Poimboeuf { 401627fce14SJosh Poimboeuf struct section *sec, *shstrtab; 402627fce14SJosh Poimboeuf size_t size = entsize * nr; 403627fce14SJosh Poimboeuf struct Elf_Scn *s; 404627fce14SJosh Poimboeuf Elf_Data *data; 405627fce14SJosh Poimboeuf 406627fce14SJosh Poimboeuf sec = malloc(sizeof(*sec)); 407627fce14SJosh Poimboeuf if (!sec) { 408627fce14SJosh Poimboeuf perror("malloc"); 409627fce14SJosh Poimboeuf return NULL; 410627fce14SJosh Poimboeuf } 411627fce14SJosh Poimboeuf memset(sec, 0, sizeof(*sec)); 412627fce14SJosh Poimboeuf 413627fce14SJosh Poimboeuf INIT_LIST_HEAD(&sec->symbol_list); 414627fce14SJosh Poimboeuf INIT_LIST_HEAD(&sec->rela_list); 415627fce14SJosh Poimboeuf hash_init(sec->rela_hash); 416627fce14SJosh Poimboeuf hash_init(sec->symbol_hash); 417627fce14SJosh Poimboeuf 418627fce14SJosh Poimboeuf list_add_tail(&sec->list, &elf->sections); 419627fce14SJosh Poimboeuf 420627fce14SJosh Poimboeuf s = elf_newscn(elf->elf); 421627fce14SJosh Poimboeuf if (!s) { 422627fce14SJosh Poimboeuf WARN_ELF("elf_newscn"); 423627fce14SJosh Poimboeuf return NULL; 424627fce14SJosh Poimboeuf } 425627fce14SJosh Poimboeuf 426627fce14SJosh Poimboeuf sec->name = strdup(name); 427627fce14SJosh Poimboeuf if (!sec->name) { 428627fce14SJosh Poimboeuf perror("strdup"); 429627fce14SJosh Poimboeuf return NULL; 430627fce14SJosh Poimboeuf } 431627fce14SJosh Poimboeuf 432627fce14SJosh Poimboeuf sec->idx = elf_ndxscn(s); 433627fce14SJosh Poimboeuf sec->len = size; 434627fce14SJosh Poimboeuf sec->changed = true; 435627fce14SJosh Poimboeuf 436627fce14SJosh Poimboeuf sec->data = elf_newdata(s); 437627fce14SJosh Poimboeuf if (!sec->data) { 438627fce14SJosh Poimboeuf WARN_ELF("elf_newdata"); 439627fce14SJosh Poimboeuf return NULL; 440627fce14SJosh Poimboeuf } 441627fce14SJosh Poimboeuf 442627fce14SJosh Poimboeuf sec->data->d_size = size; 443627fce14SJosh Poimboeuf sec->data->d_align = 1; 444627fce14SJosh Poimboeuf 445627fce14SJosh Poimboeuf if (size) { 446627fce14SJosh Poimboeuf sec->data->d_buf = malloc(size); 447627fce14SJosh Poimboeuf if (!sec->data->d_buf) { 448627fce14SJosh Poimboeuf perror("malloc"); 449627fce14SJosh Poimboeuf return NULL; 450627fce14SJosh Poimboeuf } 451627fce14SJosh Poimboeuf memset(sec->data->d_buf, 0, size); 452627fce14SJosh Poimboeuf } 453627fce14SJosh Poimboeuf 454627fce14SJosh Poimboeuf if (!gelf_getshdr(s, &sec->sh)) { 455627fce14SJosh Poimboeuf WARN_ELF("gelf_getshdr"); 456627fce14SJosh Poimboeuf return NULL; 457627fce14SJosh Poimboeuf } 458627fce14SJosh Poimboeuf 459627fce14SJosh Poimboeuf sec->sh.sh_size = size; 460627fce14SJosh Poimboeuf sec->sh.sh_entsize = entsize; 461627fce14SJosh Poimboeuf sec->sh.sh_type = SHT_PROGBITS; 462627fce14SJosh Poimboeuf sec->sh.sh_addralign = 1; 463627fce14SJosh Poimboeuf sec->sh.sh_flags = SHF_ALLOC; 464627fce14SJosh Poimboeuf 465627fce14SJosh Poimboeuf 466627fce14SJosh Poimboeuf /* Add section name to .shstrtab */ 467627fce14SJosh Poimboeuf shstrtab = find_section_by_name(elf, ".shstrtab"); 468627fce14SJosh Poimboeuf if (!shstrtab) { 469627fce14SJosh Poimboeuf WARN("can't find .shstrtab section"); 470627fce14SJosh Poimboeuf return NULL; 471627fce14SJosh Poimboeuf } 472627fce14SJosh Poimboeuf 473627fce14SJosh Poimboeuf s = elf_getscn(elf->elf, shstrtab->idx); 474627fce14SJosh Poimboeuf if (!s) { 475627fce14SJosh Poimboeuf WARN_ELF("elf_getscn"); 476627fce14SJosh Poimboeuf return NULL; 477627fce14SJosh Poimboeuf } 478627fce14SJosh Poimboeuf 479627fce14SJosh Poimboeuf data = elf_newdata(s); 480627fce14SJosh Poimboeuf if (!data) { 481627fce14SJosh Poimboeuf WARN_ELF("elf_newdata"); 482627fce14SJosh Poimboeuf return NULL; 483627fce14SJosh Poimboeuf } 484627fce14SJosh Poimboeuf 485627fce14SJosh Poimboeuf data->d_buf = sec->name; 486627fce14SJosh Poimboeuf data->d_size = strlen(name) + 1; 487627fce14SJosh Poimboeuf data->d_align = 1; 488627fce14SJosh Poimboeuf 489627fce14SJosh Poimboeuf sec->sh.sh_name = shstrtab->len; 490627fce14SJosh Poimboeuf 491627fce14SJosh Poimboeuf shstrtab->len += strlen(name) + 1; 492627fce14SJosh Poimboeuf shstrtab->changed = true; 493627fce14SJosh Poimboeuf 494627fce14SJosh Poimboeuf return sec; 495627fce14SJosh Poimboeuf } 496627fce14SJosh Poimboeuf 497627fce14SJosh Poimboeuf struct section *elf_create_rela_section(struct elf *elf, struct section *base) 498627fce14SJosh Poimboeuf { 499627fce14SJosh Poimboeuf char *relaname; 500627fce14SJosh Poimboeuf struct section *sec; 501627fce14SJosh Poimboeuf 502627fce14SJosh Poimboeuf relaname = malloc(strlen(base->name) + strlen(".rela") + 1); 503627fce14SJosh Poimboeuf if (!relaname) { 504627fce14SJosh Poimboeuf perror("malloc"); 505627fce14SJosh Poimboeuf return NULL; 506627fce14SJosh Poimboeuf } 507627fce14SJosh Poimboeuf strcpy(relaname, ".rela"); 508627fce14SJosh Poimboeuf strcat(relaname, base->name); 509627fce14SJosh Poimboeuf 510627fce14SJosh Poimboeuf sec = elf_create_section(elf, relaname, sizeof(GElf_Rela), 0); 5110998b7a0SMartin Kepplinger free(relaname); 512627fce14SJosh Poimboeuf if (!sec) 513627fce14SJosh Poimboeuf return NULL; 514627fce14SJosh Poimboeuf 515627fce14SJosh Poimboeuf base->rela = sec; 516627fce14SJosh Poimboeuf sec->base = base; 517627fce14SJosh Poimboeuf 518627fce14SJosh Poimboeuf sec->sh.sh_type = SHT_RELA; 519627fce14SJosh Poimboeuf sec->sh.sh_addralign = 8; 520627fce14SJosh Poimboeuf sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx; 521627fce14SJosh Poimboeuf sec->sh.sh_info = base->idx; 522627fce14SJosh Poimboeuf sec->sh.sh_flags = SHF_INFO_LINK; 523627fce14SJosh Poimboeuf 524627fce14SJosh Poimboeuf return sec; 525627fce14SJosh Poimboeuf } 526627fce14SJosh Poimboeuf 527627fce14SJosh Poimboeuf int elf_rebuild_rela_section(struct section *sec) 528627fce14SJosh Poimboeuf { 529627fce14SJosh Poimboeuf struct rela *rela; 530627fce14SJosh Poimboeuf int nr, idx = 0, size; 531627fce14SJosh Poimboeuf GElf_Rela *relas; 532627fce14SJosh Poimboeuf 533627fce14SJosh Poimboeuf nr = 0; 534627fce14SJosh Poimboeuf list_for_each_entry(rela, &sec->rela_list, list) 535627fce14SJosh Poimboeuf nr++; 536627fce14SJosh Poimboeuf 537627fce14SJosh Poimboeuf size = nr * sizeof(*relas); 538627fce14SJosh Poimboeuf relas = malloc(size); 539627fce14SJosh Poimboeuf if (!relas) { 540627fce14SJosh Poimboeuf perror("malloc"); 541627fce14SJosh Poimboeuf return -1; 542627fce14SJosh Poimboeuf } 543627fce14SJosh Poimboeuf 544627fce14SJosh Poimboeuf sec->data->d_buf = relas; 545627fce14SJosh Poimboeuf sec->data->d_size = size; 546627fce14SJosh Poimboeuf 547627fce14SJosh Poimboeuf sec->sh.sh_size = size; 548627fce14SJosh Poimboeuf 549627fce14SJosh Poimboeuf idx = 0; 550627fce14SJosh Poimboeuf list_for_each_entry(rela, &sec->rela_list, list) { 551627fce14SJosh Poimboeuf relas[idx].r_offset = rela->offset; 552627fce14SJosh Poimboeuf relas[idx].r_addend = rela->addend; 553627fce14SJosh Poimboeuf relas[idx].r_info = GELF_R_INFO(rela->sym->idx, rela->type); 554627fce14SJosh Poimboeuf idx++; 555627fce14SJosh Poimboeuf } 556627fce14SJosh Poimboeuf 557627fce14SJosh Poimboeuf return 0; 558627fce14SJosh Poimboeuf } 559627fce14SJosh Poimboeuf 560627fce14SJosh Poimboeuf int elf_write(struct elf *elf) 561627fce14SJosh Poimboeuf { 562627fce14SJosh Poimboeuf struct section *sec; 563627fce14SJosh Poimboeuf Elf_Scn *s; 564627fce14SJosh Poimboeuf 565627fce14SJosh Poimboeuf list_for_each_entry(sec, &elf->sections, list) { 566627fce14SJosh Poimboeuf if (sec->changed) { 567627fce14SJosh Poimboeuf s = elf_getscn(elf->elf, sec->idx); 568627fce14SJosh Poimboeuf if (!s) { 569627fce14SJosh Poimboeuf WARN_ELF("elf_getscn"); 570627fce14SJosh Poimboeuf return -1; 571627fce14SJosh Poimboeuf } 572627fce14SJosh Poimboeuf if (!gelf_update_shdr (s, &sec->sh)) { 573627fce14SJosh Poimboeuf WARN_ELF("gelf_update_shdr"); 574627fce14SJosh Poimboeuf return -1; 575627fce14SJosh Poimboeuf } 576627fce14SJosh Poimboeuf } 577627fce14SJosh Poimboeuf } 578627fce14SJosh Poimboeuf 579627fce14SJosh Poimboeuf if (elf_update(elf->elf, ELF_C_WRITE) < 0) { 580627fce14SJosh Poimboeuf WARN_ELF("elf_update"); 581627fce14SJosh Poimboeuf return -1; 582627fce14SJosh Poimboeuf } 583627fce14SJosh Poimboeuf 584627fce14SJosh Poimboeuf return 0; 585627fce14SJosh Poimboeuf } 586627fce14SJosh Poimboeuf 587442f04c3SJosh Poimboeuf void elf_close(struct elf *elf) 588442f04c3SJosh Poimboeuf { 589442f04c3SJosh Poimboeuf struct section *sec, *tmpsec; 590442f04c3SJosh Poimboeuf struct symbol *sym, *tmpsym; 591442f04c3SJosh Poimboeuf struct rela *rela, *tmprela; 592442f04c3SJosh Poimboeuf 593baa41469SJosh Poimboeuf if (elf->elf) 594baa41469SJosh Poimboeuf elf_end(elf->elf); 595baa41469SJosh Poimboeuf 596baa41469SJosh Poimboeuf if (elf->fd > 0) 597baa41469SJosh Poimboeuf close(elf->fd); 598baa41469SJosh Poimboeuf 599442f04c3SJosh Poimboeuf list_for_each_entry_safe(sec, tmpsec, &elf->sections, list) { 600a196e171SJosh Poimboeuf list_for_each_entry_safe(sym, tmpsym, &sec->symbol_list, list) { 601442f04c3SJosh Poimboeuf list_del(&sym->list); 602042ba73fSJosh Poimboeuf hash_del(&sym->hash); 603442f04c3SJosh Poimboeuf free(sym); 604442f04c3SJosh Poimboeuf } 605a196e171SJosh Poimboeuf list_for_each_entry_safe(rela, tmprela, &sec->rela_list, list) { 606442f04c3SJosh Poimboeuf list_del(&rela->list); 607042ba73fSJosh Poimboeuf hash_del(&rela->hash); 608442f04c3SJosh Poimboeuf free(rela); 609442f04c3SJosh Poimboeuf } 610442f04c3SJosh Poimboeuf list_del(&sec->list); 611442f04c3SJosh Poimboeuf free(sec); 612442f04c3SJosh Poimboeuf } 613baa41469SJosh Poimboeuf 614442f04c3SJosh Poimboeuf free(elf); 615442f04c3SJosh Poimboeuf } 616