1 /* Interface for libelf. 2 Copyright (C) 1998-2010, 2015 Red Hat, Inc. 3 This file is part of elfutils. 4 5 This file is free software; you can redistribute it and/or modify 6 it under the terms of either 7 8 * the GNU Lesser General Public License as published by the Free 9 Software Foundation; either version 3 of the License, or (at 10 your option) any later version 11 12 or 13 14 * the GNU General Public License as published by the Free 15 Software Foundation; either version 2 of the License, or (at 16 your option) any later version 17 18 or both in parallel, as here. 19 20 elfutils is distributed in the hope that it will be useful, but 21 WITHOUT ANY WARRANTY; without even the implied warranty of 22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 23 General Public License for more details. 24 25 You should have received copies of the GNU General Public License and 26 the GNU Lesser General Public License along with this program. If 27 not, see <http://www.gnu.org/licenses/>. */ 28 29 #ifndef _LIBELF_H 30 #define _LIBELF_H 1 31 32 #include <stdint.h> 33 #include <sys/types.h> 34 35 /* Get the ELF types. */ 36 #include <elf.h> 37 38 #ifndef SHF_COMPRESSED 39 /* Older glibc elf.h might not yet define the ELF compression types. */ 40 #define SHF_COMPRESSED (1 << 11) /* Section with compressed data. */ 41 42 /* Section compression header. Used when SHF_COMPRESSED is set. */ 43 44 typedef struct 45 { 46 Elf32_Word ch_type; /* Compression format. */ 47 Elf32_Word ch_size; /* Uncompressed data size. */ 48 Elf32_Word ch_addralign; /* Uncompressed data alignment. */ 49 } Elf32_Chdr; 50 51 typedef struct 52 { 53 Elf64_Word ch_type; /* Compression format. */ 54 Elf64_Word ch_reserved; 55 Elf64_Xword ch_size; /* Uncompressed data size. */ 56 Elf64_Xword ch_addralign; /* Uncompressed data alignment. */ 57 } Elf64_Chdr; 58 59 /* Legal values for ch_type (compression algorithm). */ 60 #define ELFCOMPRESS_ZLIB 1 /* ZLIB/DEFLATE algorithm. */ 61 #define ELFCOMPRESS_LOOS 0x60000000 /* Start of OS-specific. */ 62 #define ELFCOMPRESS_HIOS 0x6fffffff /* End of OS-specific. */ 63 #define ELFCOMPRESS_LOPROC 0x70000000 /* Start of processor-specific. */ 64 #define ELFCOMPRESS_HIPROC 0x7fffffff /* End of processor-specific. */ 65 #endif 66 67 #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 3) 68 # define __nonnull_attribute__(...) __attribute__ ((__nonnull__ (__VA_ARGS__))) 69 # define __deprecated_attribute__ __attribute__ ((__deprecated__)) 70 # define __pure_attribute__ __attribute__ ((__pure__)) 71 # define __const_attribute__ __attribute__ ((__const__)) 72 #else 73 # define __nonnull_attribute__(...) 74 # define __deprecated_attribute__ 75 # define __pure_attribute__ 76 # define __const_attribute__ 77 #endif 78 79 #if __GNUC__ < 4 80 #define __noreturn_attribute__ 81 #else 82 #define __noreturn_attribute__ __attribute__ ((noreturn)) 83 #endif 84 85 #ifdef __GNUC_STDC_INLINE__ 86 # define __libdw_extern_inline extern __inline __attribute__ ((__gnu_inline__)) 87 #else 88 # define __libdw_extern_inline extern __inline 89 #endif 90 91 /* Known translation types. */ 92 typedef enum 93 { 94 ELF_T_BYTE, /* unsigned char */ 95 ELF_T_ADDR, /* Elf32_Addr, Elf64_Addr, ... */ 96 ELF_T_DYN, /* Dynamic section record. */ 97 ELF_T_EHDR, /* ELF header. */ 98 ELF_T_HALF, /* Elf32_Half, Elf64_Half, ... */ 99 ELF_T_OFF, /* Elf32_Off, Elf64_Off, ... */ 100 ELF_T_PHDR, /* Program header. */ 101 ELF_T_RELA, /* Relocation entry with addend. */ 102 ELF_T_REL, /* Relocation entry. */ 103 ELF_T_SHDR, /* Section header. */ 104 ELF_T_SWORD, /* Elf32_Sword, Elf64_Sword, ... */ 105 ELF_T_SYM, /* Symbol record. */ 106 ELF_T_WORD, /* Elf32_Word, Elf64_Word, ... */ 107 ELF_T_XWORD, /* Elf32_Xword, Elf64_Xword, ... */ 108 ELF_T_SXWORD, /* Elf32_Sxword, Elf64_Sxword, ... */ 109 ELF_T_VDEF, /* Elf32_Verdef, Elf64_Verdef, ... */ 110 ELF_T_VDAUX, /* Elf32_Verdaux, Elf64_Verdaux, ... */ 111 ELF_T_VNEED, /* Elf32_Verneed, Elf64_Verneed, ... */ 112 ELF_T_VNAUX, /* Elf32_Vernaux, Elf64_Vernaux, ... */ 113 ELF_T_NHDR, /* Elf32_Nhdr, Elf64_Nhdr, ... */ 114 ELF_T_SYMINFO, /* Elf32_Syminfo, Elf64_Syminfo, ... */ 115 ELF_T_MOVE, /* Elf32_Move, Elf64_Move, ... */ 116 ELF_T_LIB, /* Elf32_Lib, Elf64_Lib, ... */ 117 ELF_T_GNUHASH, /* GNU-style hash section. */ 118 ELF_T_AUXV, /* Elf32_auxv_t, Elf64_auxv_t, ... */ 119 ELF_T_CHDR, /* Compressed, Elf32_Chdr, Elf64_Chdr, ... */ 120 ELF_T_NHDR8, /* Special GNU Properties note. Same as Nhdr, 121 except padding. */ 122 /* Keep this the last entry. */ 123 ELF_T_NUM 124 } Elf_Type; 125 126 /* Descriptor for data to be converted to or from memory format. */ 127 typedef struct 128 { 129 void *d_buf; /* Pointer to the actual data. */ 130 Elf_Type d_type; /* Type of this piece of data. */ 131 unsigned int d_version; /* ELF version. */ 132 size_t d_size; /* Size in bytes. */ 133 int64_t d_off; /* Offset into section. */ 134 size_t d_align; /* Alignment in section. */ 135 } Elf_Data; 136 137 138 /* Commands for `...'. */ 139 typedef enum 140 { 141 ELF_C_NULL, /* Nothing, terminate, or compute only. */ 142 ELF_C_READ, /* Read .. */ 143 ELF_C_RDWR, /* Read and write .. */ 144 ELF_C_WRITE, /* Write .. */ 145 ELF_C_CLR, /* Clear flag. */ 146 ELF_C_SET, /* Set flag. */ 147 ELF_C_FDDONE, /* Signal that file descriptor will not be 148 used anymore. */ 149 ELF_C_FDREAD, /* Read rest of data so that file descriptor 150 is not used anymore. */ 151 /* The following are extensions. */ 152 ELF_C_READ_MMAP, /* Read, but mmap the file if possible. */ 153 ELF_C_RDWR_MMAP, /* Read and write, with mmap. */ 154 ELF_C_WRITE_MMAP, /* Write, with mmap. */ 155 ELF_C_READ_MMAP_PRIVATE, /* Read, but memory is writable, results are 156 not written to the file. */ 157 ELF_C_EMPTY, /* Copy basic file data but not the content. */ 158 /* Keep this the last entry. */ 159 ELF_C_NUM 160 } Elf_Cmd; 161 162 163 /* Flags for the ELF structures. */ 164 enum 165 { 166 ELF_F_DIRTY = 0x1, 167 #define ELF_F_DIRTY ELF_F_DIRTY 168 ELF_F_LAYOUT = 0x4, 169 #define ELF_F_LAYOUT ELF_F_LAYOUT 170 ELF_F_PERMISSIVE = 0x8 171 #define ELF_F_PERMISSIVE ELF_F_PERMISSIVE 172 }; 173 174 /* Flags for elf_compress[_gnu]. */ 175 enum 176 { 177 ELF_CHF_FORCE = 0x1 178 #define ELF_CHF_FORCE ELF_CHF_FORCE 179 }; 180 181 /* Identification values for recognized object files. */ 182 typedef enum 183 { 184 ELF_K_NONE, /* Unknown. */ 185 ELF_K_AR, /* Archive. */ 186 ELF_K_COFF, /* Stupid old COFF. */ 187 ELF_K_ELF, /* ELF file. */ 188 /* Keep this the last entry. */ 189 ELF_K_NUM 190 } Elf_Kind; 191 192 193 /* Archive member header. */ 194 typedef struct 195 { 196 char *ar_name; /* Name of archive member. */ 197 time_t ar_date; /* File date. */ 198 uid_t ar_uid; /* User ID. */ 199 gid_t ar_gid; /* Group ID. */ 200 mode_t ar_mode; /* File mode. */ 201 int64_t ar_size; /* File size. */ 202 char *ar_rawname; /* Original name of archive member. */ 203 } Elf_Arhdr; 204 205 206 /* Archive symbol table entry. */ 207 typedef struct 208 { 209 char *as_name; /* Symbol name. */ 210 size_t as_off; /* Offset for this file in the archive. */ 211 unsigned long int as_hash; /* Hash value of the name. */ 212 } Elf_Arsym; 213 214 215 /* Descriptor for the ELF file. */ 216 typedef struct Elf Elf; 217 218 /* Descriptor for ELF file section. */ 219 typedef struct Elf_Scn Elf_Scn; 220 221 222 #ifdef __cplusplus 223 extern "C" { 224 #endif 225 226 /* Return descriptor for ELF file to work according to CMD. */ 227 extern Elf *elf_begin (int __fildes, Elf_Cmd __cmd, Elf *__ref); 228 229 /* Create a clone of an existing ELF descriptor. */ 230 extern Elf *elf_clone (Elf *__elf, Elf_Cmd __cmd); 231 232 /* Create descriptor for memory region. */ 233 extern Elf *elf_memory (char *__image, size_t __size); 234 235 /* Advance archive descriptor to next element. */ 236 extern Elf_Cmd elf_next (Elf *__elf); 237 238 /* Free resources allocated for ELF. */ 239 extern int elf_end (Elf *__elf); 240 241 /* Update ELF descriptor and write file to disk. */ 242 extern int64_t elf_update (Elf *__elf, Elf_Cmd __cmd); 243 244 /* Determine what kind of file is associated with ELF. */ 245 extern Elf_Kind elf_kind (Elf *__elf) __pure_attribute__; 246 247 /* Get the base offset for an object file. */ 248 extern int64_t elf_getbase (Elf *__elf); 249 250 251 /* Retrieve file identification data. */ 252 extern char *elf_getident (Elf *__elf, size_t *__nbytes); 253 254 /* Retrieve class-dependent object file header. */ 255 extern Elf32_Ehdr *elf32_getehdr (Elf *__elf); 256 /* Similar but this time the binary calls is ELFCLASS64. */ 257 extern Elf64_Ehdr *elf64_getehdr (Elf *__elf); 258 259 /* Create ELF header if none exists. */ 260 extern Elf32_Ehdr *elf32_newehdr (Elf *__elf); 261 /* Similar but this time the binary calls is ELFCLASS64. */ 262 extern Elf64_Ehdr *elf64_newehdr (Elf *__elf); 263 264 /* Get the number of program headers in the ELF file. If the file uses 265 more headers than can be represented in the e_phnum field of the ELF 266 header the information from the sh_info field in the zeroth section 267 header is used. */ 268 extern int elf_getphdrnum (Elf *__elf, size_t *__dst); 269 270 /* Retrieve class-dependent program header table. */ 271 extern Elf32_Phdr *elf32_getphdr (Elf *__elf); 272 /* Similar but this time the binary calls is ELFCLASS64. */ 273 extern Elf64_Phdr *elf64_getphdr (Elf *__elf); 274 275 /* Create ELF program header. */ 276 extern Elf32_Phdr *elf32_newphdr (Elf *__elf, size_t __cnt); 277 /* Similar but this time the binary calls is ELFCLASS64. */ 278 extern Elf64_Phdr *elf64_newphdr (Elf *__elf, size_t __cnt); 279 280 281 /* Get section at INDEX. */ 282 extern Elf_Scn *elf_getscn (Elf *__elf, size_t __index); 283 284 /* Get section at OFFSET. */ 285 extern Elf_Scn *elf32_offscn (Elf *__elf, Elf32_Off __offset); 286 /* Similar bug this time the binary calls is ELFCLASS64. */ 287 extern Elf_Scn *elf64_offscn (Elf *__elf, Elf64_Off __offset); 288 289 /* Get index of section. */ 290 extern size_t elf_ndxscn (Elf_Scn *__scn); 291 292 /* Get section with next section index. */ 293 extern Elf_Scn *elf_nextscn (Elf *__elf, Elf_Scn *__scn); 294 295 /* Create a new section and append it at the end of the table. */ 296 extern Elf_Scn *elf_newscn (Elf *__elf); 297 298 /* Get the section index of the extended section index table for the 299 given symbol table. */ 300 extern int elf_scnshndx (Elf_Scn *__scn); 301 302 /* Get the number of sections in the ELF file. If the file uses more 303 sections than can be represented in the e_shnum field of the ELF 304 header the information from the sh_size field in the zeroth section 305 header is used. */ 306 extern int elf_getshdrnum (Elf *__elf, size_t *__dst); 307 /* Sun messed up the implementation of 'elf_getshnum' in their implementation. 308 It was agreed to make the same functionality available under a different 309 name and obsolete the old name. */ 310 extern int elf_getshnum (Elf *__elf, size_t *__dst) 311 __deprecated_attribute__; 312 313 314 /* Get the section index of the section header string table in the ELF 315 file. If the index cannot be represented in the e_shstrndx field of 316 the ELF header the information from the sh_link field in the zeroth 317 section header is used. */ 318 extern int elf_getshdrstrndx (Elf *__elf, size_t *__dst); 319 /* Sun messed up the implementation of 'elf_getshstrndx' in their 320 implementation. It was agreed to make the same functionality available 321 under a different name and obsolete the old name. */ 322 extern int elf_getshstrndx (Elf *__elf, size_t *__dst) 323 __deprecated_attribute__; 324 325 326 /* Retrieve section header of ELFCLASS32 binary. */ 327 extern Elf32_Shdr *elf32_getshdr (Elf_Scn *__scn); 328 /* Similar for ELFCLASS64. */ 329 extern Elf64_Shdr *elf64_getshdr (Elf_Scn *__scn); 330 331 /* Returns compression header for a section if section data is 332 compressed. Returns NULL and sets elf_errno if the section isn't 333 compressed or an error occurred. */ 334 extern Elf32_Chdr *elf32_getchdr (Elf_Scn *__scn); 335 extern Elf64_Chdr *elf64_getchdr (Elf_Scn *__scn); 336 337 /* Compress or decompress the data of a section and adjust the section 338 header. 339 340 elf_compress works by setting or clearing the SHF_COMPRESS flag 341 from the section Shdr and will encode or decode a Elf32_Chdr or 342 Elf64_Chdr at the start of the section data. elf_compress_gnu will 343 encode or decode any section, but is traditionally only used for 344 sections that have a name starting with ".debug" when 345 uncompressed or ".zdebug" when compressed and stores just the 346 uncompressed size. The GNU compression method is deprecated and 347 should only be used for legacy support. 348 349 elf_compress takes a compression type that should be either zero to 350 decompress or an ELFCOMPRESS algorithm to use for compression. 351 Currently only ELFCOMPRESS_ZLIB is supported. elf_compress_gnu 352 will compress in the traditional GNU compression format when 353 compress is one and decompress the section data when compress is 354 zero. 355 356 The FLAGS argument can be zero or ELF_CHF_FORCE. If FLAGS contains 357 ELF_CHF_FORCE then it will always compress the section, even if 358 that would not reduce the size of the data section (including the 359 header). Otherwise elf_compress and elf_compress_gnu will compress 360 the section only if the total data size is reduced. 361 362 On successful compression or decompression the function returns 363 one. If (not forced) compression is requested and the data section 364 would not actually reduce in size, the section is not actually 365 compressed and zero is returned. Otherwise -1 is returned and 366 elf_errno is set. 367 368 It is an error to request compression for a section that already 369 has SHF_COMPRESSED set, or (for elf_compress) to request 370 decompression for an section that doesn't have SHF_COMPRESSED set. 371 If a section has SHF_COMPRESSED set then calling elf_compress_gnu 372 will result in an error. The section has to be decompressed first 373 using elf_compress. Calling elf_compress on a section compressed 374 with elf_compress_gnu is fine, but probably useless. 375 376 It is always an error to call these functions on SHT_NOBITS 377 sections or if the section has the SHF_ALLOC flag set. 378 elf_compress_gnu will not check whether the section name starts 379 with ".debug" or .zdebug". It is the responsibilty of the caller 380 to make sure the deprecated GNU compression method is only called 381 on correctly named sections (and to change the name of the section 382 when using elf_compress_gnu). 383 384 All previous returned Shdrs and Elf_Data buffers are invalidated by 385 this call and should no longer be accessed. 386 387 Note that although this changes the header and data returned it 388 doesn't mark the section as dirty. To keep the changes when 389 calling elf_update the section has to be flagged ELF_F_DIRTY. */ 390 extern int elf_compress (Elf_Scn *scn, int type, unsigned int flags); 391 extern int elf_compress_gnu (Elf_Scn *scn, int compress, unsigned int flags); 392 393 /* Set or clear flags for ELF file. */ 394 extern unsigned int elf_flagelf (Elf *__elf, Elf_Cmd __cmd, 395 unsigned int __flags); 396 /* Similarly for the ELF header. */ 397 extern unsigned int elf_flagehdr (Elf *__elf, Elf_Cmd __cmd, 398 unsigned int __flags); 399 /* Similarly for the ELF program header. */ 400 extern unsigned int elf_flagphdr (Elf *__elf, Elf_Cmd __cmd, 401 unsigned int __flags); 402 /* Similarly for the given ELF section. */ 403 extern unsigned int elf_flagscn (Elf_Scn *__scn, Elf_Cmd __cmd, 404 unsigned int __flags); 405 /* Similarly for the given ELF data. */ 406 extern unsigned int elf_flagdata (Elf_Data *__data, Elf_Cmd __cmd, 407 unsigned int __flags); 408 /* Similarly for the given ELF section header. */ 409 extern unsigned int elf_flagshdr (Elf_Scn *__scn, Elf_Cmd __cmd, 410 unsigned int __flags); 411 412 413 /* Get data from section while translating from file representation to 414 memory representation. The Elf_Data d_type is set based on the 415 section type if known. Otherwise d_type is set to ELF_T_BYTE. If 416 the section contains compressed data then d_type is always set to 417 ELF_T_CHDR. */ 418 extern Elf_Data *elf_getdata (Elf_Scn *__scn, Elf_Data *__data); 419 420 /* Get uninterpreted section content. */ 421 extern Elf_Data *elf_rawdata (Elf_Scn *__scn, Elf_Data *__data); 422 423 /* Create new data descriptor for section SCN. */ 424 extern Elf_Data *elf_newdata (Elf_Scn *__scn); 425 426 /* Get data translated from a chunk of the file contents as section data 427 would be for TYPE. The resulting Elf_Data pointer is valid until 428 elf_end (ELF) is called. */ 429 extern Elf_Data *elf_getdata_rawchunk (Elf *__elf, 430 int64_t __offset, size_t __size, 431 Elf_Type __type); 432 433 434 /* Return pointer to string at OFFSET in section INDEX. */ 435 extern char *elf_strptr (Elf *__elf, size_t __index, size_t __offset); 436 437 438 /* Return header of archive. */ 439 extern Elf_Arhdr *elf_getarhdr (Elf *__elf); 440 441 /* Return offset in archive for current file ELF. */ 442 extern int64_t elf_getaroff (Elf *__elf); 443 444 /* Select archive element at OFFSET. */ 445 extern size_t elf_rand (Elf *__elf, size_t __offset); 446 447 /* Get symbol table of archive. */ 448 extern Elf_Arsym *elf_getarsym (Elf *__elf, size_t *__narsyms); 449 450 451 /* Control ELF descriptor. */ 452 extern int elf_cntl (Elf *__elf, Elf_Cmd __cmd); 453 454 /* Retrieve uninterpreted file contents. */ 455 extern char *elf_rawfile (Elf *__elf, size_t *__nbytes); 456 457 458 /* Return size of array of COUNT elements of the type denoted by TYPE 459 in the external representation. The binary class is taken from ELF. 460 The result is based on version VERSION of the ELF standard. */ 461 extern size_t elf32_fsize (Elf_Type __type, size_t __count, 462 unsigned int __version) 463 __const_attribute__; 464 /* Similar but this time the binary calls is ELFCLASS64. */ 465 extern size_t elf64_fsize (Elf_Type __type, size_t __count, 466 unsigned int __version) 467 __const_attribute__; 468 469 470 /* Convert data structure from the representation in the file represented 471 by ELF to their memory representation. */ 472 extern Elf_Data *elf32_xlatetom (Elf_Data *__dest, const Elf_Data *__src, 473 unsigned int __encode); 474 /* Same for 64 bit class. */ 475 extern Elf_Data *elf64_xlatetom (Elf_Data *__dest, const Elf_Data *__src, 476 unsigned int __encode); 477 478 /* Convert data structure from to the representation in memory 479 represented by ELF file representation. */ 480 extern Elf_Data *elf32_xlatetof (Elf_Data *__dest, const Elf_Data *__src, 481 unsigned int __encode); 482 /* Same for 64 bit class. */ 483 extern Elf_Data *elf64_xlatetof (Elf_Data *__dest, const Elf_Data *__src, 484 unsigned int __encode); 485 486 487 /* Return error code of last failing function call. This value is kept 488 separately for each thread. */ 489 extern int elf_errno (void); 490 491 /* Return error string for ERROR. If ERROR is zero, return error string 492 for most recent error or NULL is none occurred. If ERROR is -1 the 493 behaviour is similar to the last case except that not NULL but a legal 494 string is returned. */ 495 extern const char *elf_errmsg (int __error); 496 497 498 /* Coordinate ELF library and application versions. */ 499 extern unsigned int elf_version (unsigned int __version); 500 501 /* Set fill bytes used to fill holes in data structures. */ 502 extern void elf_fill (int __fill); 503 504 /* Compute hash value. */ 505 extern unsigned long int elf_hash (const char *__string) 506 __pure_attribute__; 507 508 /* Compute hash value using the GNU-specific hash function. */ 509 extern unsigned long int elf_gnu_hash (const char *__string) 510 __pure_attribute__; 511 512 513 /* Compute simple checksum from permanent parts of the ELF file. */ 514 extern long int elf32_checksum (Elf *__elf); 515 /* Similar but this time the binary calls is ELFCLASS64. */ 516 extern long int elf64_checksum (Elf *__elf); 517 518 #ifdef __cplusplus 519 } 520 #endif 521 522 #endif /* libelf.h */ 523