Ulrich Drepper | b08d5a8 | 2005-07-26 05:00:05 +0000 | [diff] [blame^] | 1 | /* Return the next data element from the section after possibly converting it. |
| 2 | Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 Red Hat, Inc. |
| 3 | Written by Ulrich Drepper <drepper@redhat.com>, 1998. |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation, version 2. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program; if not, write to the Free Software Foundation, |
| 16 | Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 17 | |
| 18 | #ifdef HAVE_CONFIG_H |
| 19 | # include <config.h> |
| 20 | #endif |
| 21 | |
| 22 | #include <stddef.h> |
| 23 | #include <string.h> |
| 24 | #include <unistd.h> |
| 25 | |
| 26 | #include "libelfP.h" |
| 27 | #include "common.h" |
| 28 | #include "elf-knowledge.h" |
| 29 | |
| 30 | |
| 31 | #if _STRING_ARCH_unaligned |
| 32 | # define ALLOW_ALIGNED 1 |
| 33 | #else |
| 34 | # define ALLOW_ALIGNED 0 |
| 35 | #endif |
| 36 | |
| 37 | |
| 38 | #define TYPEIDX(Sh_Type) \ |
| 39 | (Sh_Type >= SHT_NULL && Sh_Type < SHT_NUM \ |
| 40 | ? Sh_Type \ |
| 41 | : (Sh_Type >= SHT_GNU_LIBLIST && Sh_Type <= SHT_HISUNW \ |
| 42 | ? SHT_NUM + Sh_Type - SHT_GNU_LIBLIST \ |
| 43 | : 0)) |
| 44 | |
| 45 | static const struct |
| 46 | { |
| 47 | Elf_Type type; |
| 48 | size_t size; |
| 49 | #if ALLOW_ALIGNED |
| 50 | # define AL(val) |
| 51 | #else |
| 52 | size_t align; |
| 53 | # define AL(val), val |
| 54 | #endif |
| 55 | } shtype_map[EV_NUM - 1][ELFCLASSNUM - 1][TYPEIDX (SHT_HISUNW) + 1] = |
| 56 | { |
| 57 | [EV_CURRENT - 1] = |
| 58 | { |
| 59 | [ELFCLASS32 - 1] = |
| 60 | { |
| 61 | /* Associate section types with libelf types, their sizes and |
| 62 | alignment. SHT_GNU_verdef is special since the section does |
| 63 | not contain entries of only one size. */ |
| 64 | #define DEFINE(Bits) \ |
| 65 | [SHT_SYMTAB] = { ELF_T_SYM, sizeof (ElfW2(Bits,Sym)) \ |
| 66 | AL (__alignof__ (ElfW2(Bits,Sym))) }, \ |
| 67 | [SHT_RELA] = { ELF_T_RELA, sizeof (ElfW2(Bits,Rela)) \ |
| 68 | AL (__alignof__ (ElfW2(Bits,Rela))) }, \ |
| 69 | [SHT_HASH] = { ELF_T_WORD, sizeof (ElfW2(Bits,Word)) \ |
| 70 | AL (__alignof__ (ElfW2(Bits,Word))) }, \ |
| 71 | [SHT_DYNAMIC] = { ELF_T_DYN, sizeof (ElfW2(Bits,Dyn)) \ |
| 72 | AL (__alignof__ (ElfW2(Bits,Dyn))) }, \ |
| 73 | [SHT_REL] = { ELF_T_REL, sizeof (ElfW2(Bits,Rel)) \ |
| 74 | AL (__alignof__ (ElfW2(Bits,Rel))) }, \ |
| 75 | [SHT_DYNSYM] = { ELF_T_SYM, sizeof (ElfW2(Bits,Sym)) \ |
| 76 | AL (__alignof__ (ElfW2(Bits,Sym))) }, \ |
| 77 | [SHT_INIT_ARRAY] = { ELF_T_ADDR, sizeof (ElfW2(Bits,Addr)) \ |
| 78 | AL (__alignof__ (ElfW2(Bits,Addr))) }, \ |
| 79 | [SHT_FINI_ARRAY] = { ELF_T_ADDR, sizeof (ElfW2(Bits,Addr)) \ |
| 80 | AL (__alignof__ (ElfW2(Bits,Addr))) }, \ |
| 81 | [SHT_PREINIT_ARRAY] = { ELF_T_ADDR, sizeof (ElfW2(Bits,Addr)) \ |
| 82 | AL (__alignof__ (ElfW2(Bits,Addr))) }, \ |
| 83 | [SHT_GROUP] = { ELF_T_WORD, sizeof (Elf32_Word) \ |
| 84 | AL (__alignof__ (Elf32_Word)) }, \ |
| 85 | [SHT_SYMTAB_SHNDX] = { ELF_T_WORD, sizeof (Elf32_Word) \ |
| 86 | AL (__alignof__ (Elf32_Word)) }, \ |
| 87 | [TYPEIDX (SHT_GNU_verdef)] = { ELF_T_VDEF, 1 AL (1) }, \ |
| 88 | [TYPEIDX (SHT_GNU_verneed)] = { ELF_T_VNEED, \ |
| 89 | sizeof (ElfW2(Bits,Verneed)) \ |
| 90 | AL (__alignof__ (ElfW2(Bits,Verneed)))},\ |
| 91 | [TYPEIDX (SHT_GNU_versym)] = { ELF_T_HALF, sizeof (ElfW2(Bits,Versym)) \ |
| 92 | AL (__alignof__ (ElfW2(Bits,Versym))) }, \ |
| 93 | [TYPEIDX (SHT_SUNW_syminfo)] = { ELF_T_SYMINFO, \ |
| 94 | sizeof (ElfW2(Bits,Syminfo)) \ |
| 95 | AL(__alignof__ (ElfW2(Bits,Syminfo)))},\ |
| 96 | [TYPEIDX (SHT_SUNW_move)] = { ELF_T_MOVE, sizeof (ElfW2(Bits,Move)) \ |
| 97 | AL (__alignof__ (ElfW2(Bits,Move))) }, \ |
| 98 | [TYPEIDX (SHT_GNU_LIBLIST)] = { ELF_T_LIB, sizeof (ElfW2(Bits,Lib)) \ |
| 99 | AL (__alignof__ (ElfW2(Bits,Lib))) } |
| 100 | DEFINE (32) |
| 101 | }, |
| 102 | [ELFCLASS64 - 1] = |
| 103 | { |
| 104 | DEFINE (64) |
| 105 | } |
| 106 | } |
| 107 | }; |
| 108 | |
| 109 | |
| 110 | /* Convert the data in the current section. */ |
| 111 | static void |
| 112 | convert_data (Elf_Scn *scn, int version __attribute__ ((unused)), int eclass, |
| 113 | int data, size_t size, size_t type) |
| 114 | { |
| 115 | #if ALLOW_ALIGNED |
| 116 | /* No need to compute the alignment requirement of the host. */ |
| 117 | const size_t align = 1; |
| 118 | #else |
| 119 | # if EV_NUM != 2 |
| 120 | size_t align = shtype_map[version - 1][eclass - 1][type].align; |
| 121 | # else |
| 122 | size_t align = shtype_map[0][eclass - 1][type].align; |
| 123 | # endif |
| 124 | #endif |
| 125 | |
| 126 | if (data == MY_ELFDATA) |
| 127 | { |
| 128 | if (ALLOW_ALIGNED |
| 129 | || (((size_t) ((char *) scn->rawdata_base)) & (align - 1)) == 0) |
| 130 | /* No need to copy, we can use the raw data. */ |
| 131 | scn->data_base = scn->rawdata_base; |
| 132 | else |
| 133 | { |
| 134 | scn->data_base = (char *) malloc (size); |
| 135 | if (scn->data_base == NULL) |
| 136 | { |
| 137 | __libelf_seterrno (ELF_E_NOMEM); |
| 138 | return; |
| 139 | } |
| 140 | |
| 141 | /* The copy will be appropriately aligned for direct access. */ |
| 142 | memcpy (scn->data_base, scn->rawdata_base, size); |
| 143 | } |
| 144 | } |
| 145 | else |
| 146 | { |
| 147 | xfct_t fp; |
| 148 | |
| 149 | scn->data_base = (char *) malloc (size); |
| 150 | if (scn->data_base == NULL) |
| 151 | { |
| 152 | __libelf_seterrno (ELF_E_NOMEM); |
| 153 | return; |
| 154 | } |
| 155 | |
| 156 | /* Get the conversion function. */ |
| 157 | #if EV_NUM != 2 |
| 158 | fp = __elf_xfctstom[version - 1][__libelf_version - 1][eclass - 1][type]; |
| 159 | #else |
| 160 | fp = __elf_xfctstom[0][0][eclass - 1][type]; |
| 161 | #endif |
| 162 | |
| 163 | fp (scn->data_base, scn->rawdata_base, size, 0); |
| 164 | } |
| 165 | |
| 166 | scn->data_list.data.d.d_buf = scn->data_base; |
| 167 | scn->data_list.data.d.d_size = size; |
| 168 | scn->data_list.data.d.d_type = type; |
| 169 | scn->data_list.data.d.d_off = scn->rawdata.d.d_off; |
| 170 | scn->data_list.data.d.d_align = scn->rawdata.d.d_align; |
| 171 | scn->data_list.data.d.d_version = scn->rawdata.d.d_version; |
| 172 | |
| 173 | scn->data_list.data.s = scn; |
| 174 | } |
| 175 | |
| 176 | |
| 177 | /* Store the information for the raw data in the `rawdata' element. */ |
| 178 | int |
| 179 | internal_function_def |
| 180 | __libelf_set_rawdata (Elf_Scn *scn) |
| 181 | { |
| 182 | size_t offset; |
| 183 | size_t size; |
| 184 | size_t align; |
| 185 | int type; |
| 186 | Elf *elf = scn->elf; |
| 187 | |
| 188 | if (elf->class == ELFCLASS32) |
| 189 | { |
| 190 | Elf32_Shdr *shdr = scn->shdr.e32 ?: INTUSE(elf32_getshdr) (scn); |
| 191 | |
| 192 | if (shdr == NULL) |
| 193 | /* Something went terribly wrong. */ |
| 194 | return 1; |
| 195 | |
| 196 | offset = shdr->sh_offset; |
| 197 | size = shdr->sh_size; |
| 198 | type = shdr->sh_type; |
| 199 | align = shdr->sh_addralign; |
| 200 | } |
| 201 | else |
| 202 | { |
| 203 | Elf64_Shdr *shdr = scn->shdr.e64 ?: INTUSE(elf64_getshdr) (scn); |
| 204 | |
| 205 | if (shdr == NULL) |
| 206 | /* Something went terribly wrong. */ |
| 207 | return 1; |
| 208 | |
| 209 | offset = shdr->sh_offset; |
| 210 | size = shdr->sh_size; |
| 211 | type = shdr->sh_type; |
| 212 | align = shdr->sh_addralign; |
| 213 | } |
| 214 | |
| 215 | /* If the section has no data (for whatever reason), leave the `d_buf' |
| 216 | pointer NULL. */ |
| 217 | if (size != 0 && type != SHT_NOBITS) |
| 218 | { |
| 219 | /* First a test whether the section is valid at all. */ |
| 220 | size_t entsize; |
| 221 | |
| 222 | if (type == SHT_HASH) |
| 223 | { |
| 224 | GElf_Ehdr ehdr_mem; |
| 225 | |
| 226 | entsize = SH_ENTSIZE_HASH (INTUSE(gelf_getehdr) (elf, &ehdr_mem)); |
| 227 | } |
| 228 | else |
| 229 | { |
| 230 | #if EV_NUM != 2 |
| 231 | entsize = shtype_map[__libelf_version - 1][elf->class - 1][TYPEIDX (type)].size; |
| 232 | #else |
| 233 | entsize = shtype_map[0][elf->class - 1][TYPEIDX (type)].size; |
| 234 | #endif |
| 235 | } |
| 236 | |
| 237 | /* We assume it is an array of bytes if it is none of the structured |
| 238 | sections we know of. */ |
| 239 | if (entsize == 0) |
| 240 | entsize = 1; |
| 241 | |
| 242 | if (size % entsize != 0) |
| 243 | { |
| 244 | __libelf_seterrno (ELF_E_INVALID_DATA); |
| 245 | return 1; |
| 246 | } |
| 247 | |
| 248 | /* We can use the mapped or loaded data if available. */ |
| 249 | if (elf->map_address != NULL) |
| 250 | { |
| 251 | /* First see whether the information in the section header is |
| 252 | valid and it does not ask for too much. */ |
| 253 | if (offset + size > elf->maximum_size) |
| 254 | { |
| 255 | /* Something is wrong. */ |
| 256 | __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); |
| 257 | return 1; |
| 258 | } |
| 259 | |
| 260 | scn->rawdata_base = scn->rawdata.d.d_buf |
| 261 | = (char *) elf->map_address + elf->start_offset + offset; |
| 262 | } |
| 263 | else if (elf->fildes != -1) |
| 264 | { |
| 265 | /* We have to read the data from the file. Allocate the needed |
| 266 | memory. */ |
| 267 | scn->rawdata_base = scn->rawdata.d.d_buf |
| 268 | = (char *) malloc (size); |
| 269 | if (scn->rawdata.d.d_buf == NULL) |
| 270 | { |
| 271 | __libelf_seterrno (ELF_E_NOMEM); |
| 272 | return 1; |
| 273 | } |
| 274 | |
| 275 | if ((size_t) pread (elf->fildes, scn->rawdata.d.d_buf, size, |
| 276 | elf->start_offset + offset) != size) |
| 277 | { |
| 278 | /* Cannot read the data. */ |
| 279 | free (scn->rawdata.d.d_buf); |
| 280 | scn->rawdata_base = scn->rawdata.d.d_buf = NULL; |
| 281 | __libelf_seterrno (ELF_E_READ_ERROR); |
| 282 | return 1; |
| 283 | } |
| 284 | } |
| 285 | else |
| 286 | { |
| 287 | /* The file descriptor is already closed, we cannot get the data |
| 288 | anymore. */ |
| 289 | __libelf_seterrno (ELF_E_FD_DISABLED); |
| 290 | return 1; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | scn->rawdata.d.d_size = size; |
| 295 | /* Some broken ELF ABI for 64-bit machines use the wrong hash table |
| 296 | entry size. See elf-knowledge.h for more information. */ |
| 297 | if (type == SHT_HASH && elf->class == ELFCLASS64) |
| 298 | { |
| 299 | GElf_Ehdr ehdr_mem; |
| 300 | |
| 301 | scn->rawdata.d.d_type |
| 302 | = (SH_ENTSIZE_HASH (INTUSE(gelf_getehdr) (elf, &ehdr_mem)) |
| 303 | == 4 ? ELF_T_WORD : ELF_T_XWORD); |
| 304 | } |
| 305 | else |
| 306 | { |
| 307 | #if EV_NUM != 2 |
| 308 | scn->rawdata.d.d_type = |
| 309 | shtype_map[__libelf_version - 1][elf->class - 1][TYPEIDX (type)].type; |
| 310 | #else |
| 311 | scn->rawdata.d.d_type = |
| 312 | shtype_map[0][elf->class - 1][TYPEIDX (type)].type; |
| 313 | #endif |
| 314 | } |
| 315 | scn->rawdata.d.d_off = 0; |
| 316 | scn->rawdata.d.d_align = align; |
| 317 | if (elf->class == ELFCLASS32 |
| 318 | || (offsetof (struct Elf, state.elf32.ehdr) |
| 319 | == offsetof (struct Elf, state.elf64.ehdr))) |
| 320 | scn->rawdata.d.d_version = |
| 321 | elf->state.elf32.ehdr->e_ident[EI_VERSION]; |
| 322 | else |
| 323 | scn->rawdata.d.d_version = |
| 324 | elf->state.elf64.ehdr->e_ident[EI_VERSION]; |
| 325 | |
| 326 | scn->rawdata.s = scn; |
| 327 | |
| 328 | scn->data_read = 1; |
| 329 | |
| 330 | /* We actually read data from the file. At least we tried. */ |
| 331 | scn->flags |= ELF_F_FILEDATA; |
| 332 | |
| 333 | return 0; |
| 334 | } |
| 335 | |
| 336 | |
| 337 | Elf_Data * |
| 338 | elf_getdata (scn, data) |
| 339 | Elf_Scn *scn; |
| 340 | Elf_Data *data; |
| 341 | { |
| 342 | Elf_Data *result = NULL; |
| 343 | Elf *elf; |
| 344 | |
| 345 | if (scn == NULL) |
| 346 | return NULL; |
| 347 | |
| 348 | if (unlikely (scn->elf->kind != ELF_K_ELF)) |
| 349 | { |
| 350 | __libelf_seterrno (ELF_E_INVALID_HANDLE); |
| 351 | return NULL; |
| 352 | } |
| 353 | |
| 354 | /* We will need this multiple times later on. */ |
| 355 | elf = scn->elf; |
| 356 | |
| 357 | rwlock_rdlock (elf->lock); |
| 358 | |
| 359 | /* If `data' is not NULL this means we are not addressing the initial |
| 360 | data in the file. But this also means this data is already read |
| 361 | (since otherwise it is not possible to have a valid `data' pointer) |
| 362 | and all the data structures are initialized as well. In this case |
| 363 | we can simply walk the list of data records. */ |
| 364 | if (data != NULL) |
| 365 | { |
| 366 | Elf_Data_List *runp; |
| 367 | |
| 368 | /* It is not possible that if DATA is not NULL the first entry is |
| 369 | returned. But this also means that there must be a first data |
| 370 | entry. */ |
| 371 | if (scn->data_list_rear == NULL |
| 372 | /* The section the reference data is for must match the section |
| 373 | parameter. */ |
| 374 | || unlikely (((Elf_Data_Scn *) data)->s != scn)) |
| 375 | { |
| 376 | __libelf_seterrno (ELF_E_DATA_MISMATCH); |
| 377 | goto out; |
| 378 | } |
| 379 | |
| 380 | /* We start searching with the first entry. */ |
| 381 | runp = &scn->data_list; |
| 382 | |
| 383 | while (1) |
| 384 | { |
| 385 | /* If `data' does not match any known record punt. */ |
| 386 | if (runp == NULL) |
| 387 | { |
| 388 | __libelf_seterrno (ELF_E_DATA_MISMATCH); |
| 389 | goto out; |
| 390 | } |
| 391 | |
| 392 | if (&runp->data.d == data) |
| 393 | /* Found the entry. */ |
| 394 | break; |
| 395 | |
| 396 | runp = runp->next; |
| 397 | } |
| 398 | |
| 399 | /* Return the data for the next data record. */ |
| 400 | result = runp->next ? &runp->next->data.d : NULL; |
| 401 | goto out; |
| 402 | } |
| 403 | |
| 404 | /* If the data for this section was not yet initialized do it now. */ |
| 405 | if (scn->data_read == 0) |
| 406 | { |
| 407 | /* We cannot acquire a write lock while we are holding a read |
| 408 | lock. Therefore give up the read lock and then get the write |
| 409 | lock. But this means that the data could meanwhile be |
| 410 | modified, therefore start the tests again. */ |
| 411 | rwlock_unlock (elf->lock); |
| 412 | rwlock_wrlock (elf->lock); |
| 413 | |
| 414 | /* Read the data from the file. There is always a file (or |
| 415 | memory region) associated with this descriptor since |
| 416 | otherwise the `data_read' flag would be set. */ |
| 417 | if (scn->data_read == 0 && __libelf_set_rawdata (scn) != 0) |
| 418 | /* Something went wrong. The error value is already set. */ |
| 419 | goto out; |
| 420 | } |
| 421 | |
| 422 | /* At this point we know the raw data is available. But it might be |
| 423 | empty in case the section has size zero (for whatever reason). |
| 424 | Now create the converted data in case this is necessary. */ |
| 425 | if (scn->data_list_rear == NULL) |
| 426 | { |
| 427 | if (scn->rawdata.d.d_buf != NULL && scn->rawdata.d.d_size > 0) |
| 428 | /* Convert according to the version and the type. */ |
| 429 | convert_data (scn, __libelf_version, elf->class, |
| 430 | (elf->class == ELFCLASS32 |
| 431 | || (offsetof (struct Elf, state.elf32.ehdr) |
| 432 | == offsetof (struct Elf, state.elf64.ehdr)) |
| 433 | ? elf->state.elf32.ehdr->e_ident[EI_DATA] |
| 434 | : elf->state.elf64.ehdr->e_ident[EI_DATA]), |
| 435 | scn->rawdata.d.d_size, scn->rawdata.d.d_type); |
| 436 | else |
| 437 | /* This is an empty or NOBITS section. There is no buffer but |
| 438 | the size information etc is important. */ |
| 439 | scn->data_list.data.d = scn->rawdata.d; |
| 440 | |
| 441 | scn->data_list_rear = &scn->data_list; |
| 442 | } |
| 443 | |
| 444 | /* If no data is present we cannot return any. */ |
| 445 | if (scn->data_list_rear != NULL) |
| 446 | /* Return the first data element in the list. */ |
| 447 | result = &scn->data_list.data.d; |
| 448 | |
| 449 | out: |
| 450 | rwlock_unlock (elf->lock); |
| 451 | |
| 452 | return result; |
| 453 | } |
| 454 | INTDEF(elf_getdata) |