1 // SPDX-License-Identifier: GPL-2.0 2 #include "symbol.h" 3 #include "util.h" 4 5 #include <errno.h> 6 #include <stdio.h> 7 #include <fcntl.h> 8 #include <string.h> 9 #include <byteswap.h> 10 #include <sys/stat.h> 11 12 13 static bool check_need_swap(int file_endian) 14 { 15 const int data = 1; 16 u8 *check = (u8 *)&data; 17 int host_endian; 18 19 if (check[0] == 1) 20 host_endian = ELFDATA2LSB; 21 else 22 host_endian = ELFDATA2MSB; 23 24 return host_endian != file_endian; 25 } 26 27 #define NOTE_ALIGN(sz) (((sz) + 3) & ~3) 28 29 #define NT_GNU_BUILD_ID 3 30 31 static int read_build_id(void *note_data, size_t note_len, void *bf, 32 size_t size, bool need_swap) 33 { 34 struct { 35 u32 n_namesz; 36 u32 n_descsz; 37 u32 n_type; 38 } *nhdr; 39 void *ptr; 40 41 ptr = note_data; 42 while (ptr < (note_data + note_len)) { 43 const char *name; 44 size_t namesz, descsz; 45 46 nhdr = ptr; 47 if (need_swap) { 48 nhdr->n_namesz = bswap_32(nhdr->n_namesz); 49 nhdr->n_descsz = bswap_32(nhdr->n_descsz); 50 nhdr->n_type = bswap_32(nhdr->n_type); 51 } 52 53 namesz = NOTE_ALIGN(nhdr->n_namesz); 54 descsz = NOTE_ALIGN(nhdr->n_descsz); 55 56 ptr += sizeof(*nhdr); 57 name = ptr; 58 ptr += namesz; 59 if (nhdr->n_type == NT_GNU_BUILD_ID && 60 nhdr->n_namesz == sizeof("GNU")) { 61 if (memcmp(name, "GNU", sizeof("GNU")) == 0) { 62 size_t sz = min(size, descsz); 63 memcpy(bf, ptr, sz); 64 memset(bf + sz, 0, size - sz); 65 return 0; 66 } 67 } 68 ptr += descsz; 69 } 70 71 return -1; 72 } 73 74 int filename__read_debuglink(const char *filename __maybe_unused, 75 char *debuglink __maybe_unused, 76 size_t size __maybe_unused) 77 { 78 return -1; 79 } 80 81 /* 82 * Just try PT_NOTE header otherwise fails 83 */ 84 int filename__read_build_id(const char *filename, void *bf, size_t size) 85 { 86 FILE *fp; 87 int ret = -1; 88 bool need_swap = false; 89 u8 e_ident[EI_NIDENT]; 90 size_t buf_size; 91 void *buf; 92 int i; 93 94 fp = fopen(filename, "r"); 95 if (fp == NULL) 96 return -1; 97 98 if (fread(e_ident, sizeof(e_ident), 1, fp) != 1) 99 goto out; 100 101 if (memcmp(e_ident, ELFMAG, SELFMAG) || 102 e_ident[EI_VERSION] != EV_CURRENT) 103 goto out; 104 105 need_swap = check_need_swap(e_ident[EI_DATA]); 106 107 /* for simplicity */ 108 fseek(fp, 0, SEEK_SET); 109 110 if (e_ident[EI_CLASS] == ELFCLASS32) { 111 Elf32_Ehdr ehdr; 112 Elf32_Phdr *phdr; 113 114 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) 115 goto out; 116 117 if (need_swap) { 118 ehdr.e_phoff = bswap_32(ehdr.e_phoff); 119 ehdr.e_phentsize = bswap_16(ehdr.e_phentsize); 120 ehdr.e_phnum = bswap_16(ehdr.e_phnum); 121 } 122 123 buf_size = ehdr.e_phentsize * ehdr.e_phnum; 124 buf = malloc(buf_size); 125 if (buf == NULL) 126 goto out; 127 128 fseek(fp, ehdr.e_phoff, SEEK_SET); 129 if (fread(buf, buf_size, 1, fp) != 1) 130 goto out_free; 131 132 for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { 133 void *tmp; 134 long offset; 135 136 if (need_swap) { 137 phdr->p_type = bswap_32(phdr->p_type); 138 phdr->p_offset = bswap_32(phdr->p_offset); 139 phdr->p_filesz = bswap_32(phdr->p_filesz); 140 } 141 142 if (phdr->p_type != PT_NOTE) 143 continue; 144 145 buf_size = phdr->p_filesz; 146 offset = phdr->p_offset; 147 tmp = realloc(buf, buf_size); 148 if (tmp == NULL) 149 goto out_free; 150 151 buf = tmp; 152 fseek(fp, offset, SEEK_SET); 153 if (fread(buf, buf_size, 1, fp) != 1) 154 goto out_free; 155 156 ret = read_build_id(buf, buf_size, bf, size, need_swap); 157 if (ret == 0) 158 ret = size; 159 break; 160 } 161 } else { 162 Elf64_Ehdr ehdr; 163 Elf64_Phdr *phdr; 164 165 if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) 166 goto out; 167 168 if (need_swap) { 169 ehdr.e_phoff = bswap_64(ehdr.e_phoff); 170 ehdr.e_phentsize = bswap_16(ehdr.e_phentsize); 171 ehdr.e_phnum = bswap_16(ehdr.e_phnum); 172 } 173 174 buf_size = ehdr.e_phentsize * ehdr.e_phnum; 175 buf = malloc(buf_size); 176 if (buf == NULL) 177 goto out; 178 179 fseek(fp, ehdr.e_phoff, SEEK_SET); 180 if (fread(buf, buf_size, 1, fp) != 1) 181 goto out_free; 182 183 for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { 184 void *tmp; 185 long offset; 186 187 if (need_swap) { 188 phdr->p_type = bswap_32(phdr->p_type); 189 phdr->p_offset = bswap_64(phdr->p_offset); 190 phdr->p_filesz = bswap_64(phdr->p_filesz); 191 } 192 193 if (phdr->p_type != PT_NOTE) 194 continue; 195 196 buf_size = phdr->p_filesz; 197 offset = phdr->p_offset; 198 tmp = realloc(buf, buf_size); 199 if (tmp == NULL) 200 goto out_free; 201 202 buf = tmp; 203 fseek(fp, offset, SEEK_SET); 204 if (fread(buf, buf_size, 1, fp) != 1) 205 goto out_free; 206 207 ret = read_build_id(buf, buf_size, bf, size, need_swap); 208 if (ret == 0) 209 ret = size; 210 break; 211 } 212 } 213 out_free: 214 free(buf); 215 out: 216 fclose(fp); 217 return ret; 218 } 219 220 int sysfs__read_build_id(const char *filename, void *build_id, size_t size) 221 { 222 int fd; 223 int ret = -1; 224 struct stat stbuf; 225 size_t buf_size; 226 void *buf; 227 228 fd = open(filename, O_RDONLY); 229 if (fd < 0) 230 return -1; 231 232 if (fstat(fd, &stbuf) < 0) 233 goto out; 234 235 buf_size = stbuf.st_size; 236 buf = malloc(buf_size); 237 if (buf == NULL) 238 goto out; 239 240 if (read(fd, buf, buf_size) != (ssize_t) buf_size) 241 goto out_free; 242 243 ret = read_build_id(buf, buf_size, build_id, size, false); 244 out_free: 245 free(buf); 246 out: 247 close(fd); 248 return ret; 249 } 250 251 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, 252 enum dso_binary_type type) 253 { 254 int fd = open(name, O_RDONLY); 255 if (fd < 0) 256 goto out_errno; 257 258 ss->name = strdup(name); 259 if (!ss->name) 260 goto out_close; 261 262 ss->fd = fd; 263 ss->type = type; 264 265 return 0; 266 out_close: 267 close(fd); 268 out_errno: 269 dso->load_errno = errno; 270 return -1; 271 } 272 273 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused) 274 { 275 /* Assume all sym sources could be a runtime image. */ 276 return true; 277 } 278 279 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused) 280 { 281 return false; 282 } 283 284 void symsrc__destroy(struct symsrc *ss) 285 { 286 zfree(&ss->name); 287 close(ss->fd); 288 } 289 290 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused, 291 struct symsrc *ss __maybe_unused) 292 { 293 return 0; 294 } 295 296 static int fd__is_64_bit(int fd) 297 { 298 u8 e_ident[EI_NIDENT]; 299 300 if (lseek(fd, 0, SEEK_SET)) 301 return -1; 302 303 if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident)) 304 return -1; 305 306 if (memcmp(e_ident, ELFMAG, SELFMAG) || 307 e_ident[EI_VERSION] != EV_CURRENT) 308 return -1; 309 310 return e_ident[EI_CLASS] == ELFCLASS64; 311 } 312 313 enum dso_type dso__type_fd(int fd) 314 { 315 Elf64_Ehdr ehdr; 316 int ret; 317 318 ret = fd__is_64_bit(fd); 319 if (ret < 0) 320 return DSO__TYPE_UNKNOWN; 321 322 if (ret) 323 return DSO__TYPE_64BIT; 324 325 if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) 326 return DSO__TYPE_UNKNOWN; 327 328 if (ehdr.e_machine == EM_X86_64) 329 return DSO__TYPE_X32BIT; 330 331 return DSO__TYPE_32BIT; 332 } 333 334 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused, 335 struct symsrc *ss, 336 struct symsrc *runtime_ss __maybe_unused, 337 int kmodule __maybe_unused) 338 { 339 unsigned char build_id[BUILD_ID_SIZE]; 340 int ret; 341 342 ret = fd__is_64_bit(ss->fd); 343 if (ret >= 0) 344 dso->is_64_bit = ret; 345 346 if (filename__read_build_id(ss->name, build_id, BUILD_ID_SIZE) > 0) { 347 dso__set_build_id(dso, build_id); 348 } 349 return 0; 350 } 351 352 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused, 353 mapfn_t mapfn __maybe_unused, void *data __maybe_unused, 354 bool *is_64_bit __maybe_unused) 355 { 356 return -1; 357 } 358 359 int kcore_extract__create(struct kcore_extract *kce __maybe_unused) 360 { 361 return -1; 362 } 363 364 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused) 365 { 366 } 367 368 int kcore_copy(const char *from_dir __maybe_unused, 369 const char *to_dir __maybe_unused) 370 { 371 return -1; 372 } 373 374 void symbol__elf_init(void) 375 { 376 } 377 378 char *dso__demangle_sym(struct dso *dso __maybe_unused, 379 int kmodule __maybe_unused, 380 const char *elf_name __maybe_unused) 381 { 382 return NULL; 383 } 384