1 #include "dso.h" 2 #include "symbol.h" 3 #include "symsrc.h" 4 5 #include <errno.h> 6 #include <unistd.h> 7 #include <fcntl.h> 8 #include <string.h> 9 #include <stdlib.h> 10 #include <byteswap.h> 11 #include <sys/stat.h> 12 #include <linux/zalloc.h> 13 #include <internal/lib.h> 14 15 static bool check_need_swap(int file_endian) 16 { 17 const int data = 1; 18 u8 *check = (u8 *)&data; 19 int host_endian; 20 21 if (check[0] == 1) 22 host_endian = ELFDATA2LSB; 23 else 24 host_endian = ELFDATA2MSB; 25 26 return host_endian != file_endian; 27 } 28 29 #define NOTE_ALIGN(sz) (((sz) + 3) & ~3) 30 31 #define NT_GNU_BUILD_ID 3 32 33 static int read_build_id(void *note_data, size_t note_len, struct build_id *bid, 34 bool need_swap) 35 { 36 size_t size = sizeof(bid->data); 37 struct { 38 u32 n_namesz; 39 u32 n_descsz; 40 u32 n_type; 41 } *nhdr; 42 void *ptr; 43 44 ptr = note_data; 45 while ((ptr + sizeof(*nhdr)) < (note_data + note_len)) { 46 const char *name; 47 size_t namesz, descsz; 48 49 nhdr = ptr; 50 if (need_swap) { 51 nhdr->n_namesz = bswap_32(nhdr->n_namesz); 52 nhdr->n_descsz = bswap_32(nhdr->n_descsz); 53 nhdr->n_type = bswap_32(nhdr->n_type); 54 } 55 56 namesz = NOTE_ALIGN(nhdr->n_namesz); 57 descsz = NOTE_ALIGN(nhdr->n_descsz); 58 59 ptr += sizeof(*nhdr); 60 name = ptr; 61 ptr += namesz; 62 if (nhdr->n_type == NT_GNU_BUILD_ID && 63 nhdr->n_namesz == sizeof("GNU")) { 64 if (memcmp(name, "GNU", sizeof("GNU")) == 0) { 65 size_t sz = min(size, descsz); 66 memcpy(bid->data, ptr, sz); 67 memset(bid->data + sz, 0, size - sz); 68 bid->size = sz; 69 return 0; 70 } 71 } 72 ptr += descsz; 73 } 74 75 return -1; 76 } 77 78 int filename__read_debuglink(const char *filename __maybe_unused, 79 char *debuglink __maybe_unused, 80 size_t size __maybe_unused) 81 { 82 return -1; 83 } 84 85 /* 86 * Just try PT_NOTE header otherwise fails 87 */ 88 int filename__read_build_id(const char *filename, struct build_id *bid) 89 { 90 int fd, ret = -1; 91 bool need_swap = false, elf32; 92 union { 93 struct { 94 Elf32_Ehdr ehdr32; 95 Elf32_Phdr *phdr32; 96 }; 97 struct { 98 Elf64_Ehdr ehdr64; 99 Elf64_Phdr *phdr64; 100 }; 101 } hdrs; 102 void *phdr, *buf = NULL; 103 ssize_t phdr_size, ehdr_size, buf_size = 0; 104 105 if (!filename) 106 return -EFAULT; 107 108 errno = 0; 109 if (!is_regular_file(filename)) 110 return errno == 0 ? -EWOULDBLOCK : -errno; 111 112 fd = open(filename, O_RDONLY); 113 if (fd < 0) 114 return -1; 115 116 if (read(fd, hdrs.ehdr32.e_ident, EI_NIDENT) != EI_NIDENT) 117 goto out; 118 119 if (memcmp(hdrs.ehdr32.e_ident, ELFMAG, SELFMAG) || 120 hdrs.ehdr32.e_ident[EI_VERSION] != EV_CURRENT) 121 goto out; 122 123 need_swap = check_need_swap(hdrs.ehdr32.e_ident[EI_DATA]); 124 elf32 = hdrs.ehdr32.e_ident[EI_CLASS] == ELFCLASS32; 125 ehdr_size = (elf32 ? sizeof(hdrs.ehdr32) : sizeof(hdrs.ehdr64)) - EI_NIDENT; 126 127 if (read(fd, 128 (elf32 ? (void *)&hdrs.ehdr32 : (void *)&hdrs.ehdr64) + EI_NIDENT, 129 ehdr_size) != ehdr_size) 130 goto out; 131 132 if (need_swap) { 133 if (elf32) { 134 hdrs.ehdr32.e_phoff = bswap_32(hdrs.ehdr32.e_phoff); 135 hdrs.ehdr32.e_phentsize = bswap_16(hdrs.ehdr32.e_phentsize); 136 hdrs.ehdr32.e_phnum = bswap_16(hdrs.ehdr32.e_phnum); 137 } else { 138 hdrs.ehdr64.e_phoff = bswap_64(hdrs.ehdr64.e_phoff); 139 hdrs.ehdr64.e_phentsize = bswap_16(hdrs.ehdr64.e_phentsize); 140 hdrs.ehdr64.e_phnum = bswap_16(hdrs.ehdr64.e_phnum); 141 } 142 } 143 if ((elf32 && hdrs.ehdr32.e_phentsize != sizeof(Elf32_Phdr)) || 144 (!elf32 && hdrs.ehdr64.e_phentsize != sizeof(Elf64_Phdr))) 145 goto out; 146 147 phdr_size = elf32 ? sizeof(Elf32_Phdr) * hdrs.ehdr32.e_phnum 148 : sizeof(Elf64_Phdr) * hdrs.ehdr64.e_phnum; 149 phdr = malloc(phdr_size); 150 if (phdr == NULL) 151 goto out; 152 153 lseek(fd, elf32 ? hdrs.ehdr32.e_phoff : hdrs.ehdr64.e_phoff, SEEK_SET); 154 if (read(fd, phdr, phdr_size) != phdr_size) 155 goto out_free; 156 157 if (elf32) 158 hdrs.phdr32 = phdr; 159 else 160 hdrs.phdr64 = phdr; 161 162 for (int i = 0; i < (elf32 ? hdrs.ehdr32.e_phnum : hdrs.ehdr64.e_phnum); i++) { 163 ssize_t p_filesz; 164 165 if (need_swap) { 166 if (elf32) { 167 hdrs.phdr32[i].p_type = bswap_32(hdrs.phdr32[i].p_type); 168 hdrs.phdr32[i].p_offset = bswap_32(hdrs.phdr32[i].p_offset); 169 hdrs.phdr32[i].p_filesz = bswap_32(hdrs.phdr32[i].p_offset); 170 } else { 171 hdrs.phdr64[i].p_type = bswap_32(hdrs.phdr64[i].p_type); 172 hdrs.phdr64[i].p_offset = bswap_64(hdrs.phdr64[i].p_offset); 173 hdrs.phdr64[i].p_filesz = bswap_64(hdrs.phdr64[i].p_filesz); 174 } 175 } 176 if ((elf32 ? hdrs.phdr32[i].p_type : hdrs.phdr64[i].p_type) != PT_NOTE) 177 continue; 178 179 p_filesz = elf32 ? hdrs.phdr32[i].p_filesz : hdrs.phdr64[i].p_filesz; 180 if (p_filesz > buf_size) { 181 void *tmp; 182 183 buf_size = p_filesz; 184 tmp = realloc(buf, buf_size); 185 if (tmp == NULL) 186 goto out_free; 187 buf = tmp; 188 } 189 lseek(fd, elf32 ? hdrs.phdr32[i].p_offset : hdrs.phdr64[i].p_offset, SEEK_SET); 190 if (read(fd, buf, p_filesz) != p_filesz) 191 goto out_free; 192 193 ret = read_build_id(buf, p_filesz, bid, need_swap); 194 if (ret == 0) { 195 ret = bid->size; 196 break; 197 } 198 } 199 out_free: 200 free(buf); 201 free(phdr); 202 out: 203 close(fd); 204 return ret; 205 } 206 207 int sysfs__read_build_id(const char *filename, struct build_id *bid) 208 { 209 int fd; 210 int ret = -1; 211 struct stat stbuf; 212 size_t buf_size; 213 void *buf; 214 215 fd = open(filename, O_RDONLY); 216 if (fd < 0) 217 return -1; 218 219 if (fstat(fd, &stbuf) < 0) 220 goto out; 221 222 buf_size = stbuf.st_size; 223 buf = malloc(buf_size); 224 if (buf == NULL) 225 goto out; 226 227 if (read(fd, buf, buf_size) != (ssize_t) buf_size) 228 goto out_free; 229 230 ret = read_build_id(buf, buf_size, bid, false); 231 out_free: 232 free(buf); 233 out: 234 close(fd); 235 return ret; 236 } 237 238 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, 239 enum dso_binary_type type) 240 { 241 int fd = open(name, O_RDONLY); 242 if (fd < 0) 243 goto out_errno; 244 245 ss->name = strdup(name); 246 if (!ss->name) 247 goto out_close; 248 249 ss->fd = fd; 250 ss->type = type; 251 252 return 0; 253 out_close: 254 close(fd); 255 out_errno: 256 RC_CHK_ACCESS(dso)->load_errno = errno; 257 return -1; 258 } 259 260 bool symsrc__possibly_runtime(struct symsrc *ss __maybe_unused) 261 { 262 /* Assume all sym sources could be a runtime image. */ 263 return true; 264 } 265 266 bool symsrc__has_symtab(struct symsrc *ss __maybe_unused) 267 { 268 return false; 269 } 270 271 void symsrc__destroy(struct symsrc *ss) 272 { 273 zfree(&ss->name); 274 close(ss->fd); 275 } 276 277 int dso__synthesize_plt_symbols(struct dso *dso __maybe_unused, 278 struct symsrc *ss __maybe_unused) 279 { 280 return 0; 281 } 282 283 static int fd__is_64_bit(int fd) 284 { 285 u8 e_ident[EI_NIDENT]; 286 287 if (lseek(fd, 0, SEEK_SET)) 288 return -1; 289 290 if (readn(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident)) 291 return -1; 292 293 if (memcmp(e_ident, ELFMAG, SELFMAG) || 294 e_ident[EI_VERSION] != EV_CURRENT) 295 return -1; 296 297 return e_ident[EI_CLASS] == ELFCLASS64; 298 } 299 300 enum dso_type dso__type_fd(int fd) 301 { 302 Elf64_Ehdr ehdr; 303 int ret; 304 305 ret = fd__is_64_bit(fd); 306 if (ret < 0) 307 return DSO__TYPE_UNKNOWN; 308 309 if (ret) 310 return DSO__TYPE_64BIT; 311 312 if (readn(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr)) 313 return DSO__TYPE_UNKNOWN; 314 315 if (ehdr.e_machine == EM_X86_64) 316 return DSO__TYPE_X32BIT; 317 318 return DSO__TYPE_32BIT; 319 } 320 321 int dso__load_sym(struct dso *dso, struct map *map __maybe_unused, 322 struct symsrc *ss, 323 struct symsrc *runtime_ss __maybe_unused, 324 int kmodule __maybe_unused) 325 { 326 struct build_id bid = { .size = 0, }; 327 int ret; 328 329 ret = fd__is_64_bit(ss->fd); 330 if (ret >= 0) 331 RC_CHK_ACCESS(dso)->is_64_bit = ret; 332 333 if (filename__read_build_id(ss->name, &bid) > 0) 334 dso__set_build_id(dso, &bid); 335 return 0; 336 } 337 338 int file__read_maps(int fd __maybe_unused, bool exe __maybe_unused, 339 mapfn_t mapfn __maybe_unused, void *data __maybe_unused, 340 bool *is_64_bit __maybe_unused) 341 { 342 return -1; 343 } 344 345 int kcore_extract__create(struct kcore_extract *kce __maybe_unused) 346 { 347 return -1; 348 } 349 350 void kcore_extract__delete(struct kcore_extract *kce __maybe_unused) 351 { 352 } 353 354 int kcore_copy(const char *from_dir __maybe_unused, 355 const char *to_dir __maybe_unused) 356 { 357 return -1; 358 } 359 360 void symbol__elf_init(void) 361 { 362 } 363 364 bool filename__has_section(const char *filename __maybe_unused, const char *sec __maybe_unused) 365 { 366 return false; 367 } 368