elftools/elf/elffile.py

   1 #-------------------------------------------------------------------------------
   2 # elftools: elf/elffile.py
   3 #
   4 # ELFFile - main class for accessing ELF files
   5 #
   6 # Eli Bendersky (eliben@gmail.com)
   7 # This code is in the public domain
   8 #-------------------------------------------------------------------------------
   9 import io
  10 import os
  11 import struct
  12 import zlib
  13
  14 try:
  15     import resource
  16     PAGESIZE = resource.getpagesize()
  17 except ImportError:
  18     try:
  19         # Windows system
  20         import mmap
  21         PAGESIZE = mmap.PAGESIZE
  22     except ImportError:
  23         # Jython
  24         PAGESIZE = 4096
  25
  26 from ..common.py3compat import BytesIO
  27 from ..common.exceptions import ELFError, ELFParseError
  28 from ..common.utils import struct_parse, elf_assert
  29 from .structs import ELFStructs
  30 from .sections import (
  31         Section, StringTableSection, SymbolTableSection,
  32         SymbolTableIndexSection, SUNWSyminfoTableSection, NullSection,
  33         NoteSection, StabSection, ARMAttributesSection)
  34 from .dynamic import DynamicSection, DynamicSegment
  35 from .relocation import (RelocationSection, RelocationHandler,
  36         RelrRelocationSection)
  37 from .gnuversions import (
  38         GNUVerNeedSection, GNUVerDefSection,
  39         GNUVerSymSection)
  40 from .segments import Segment, InterpSegment, NoteSegment
  41 from ..dwarf.dwarfinfo import DWARFInfo, DebugSectionDescriptor, DwarfConfig
  42 from ..ehabi.ehabiinfo import EHABIInfo
  43 from .hash import ELFHashSection, GNUHashSection
  44 from .constants import SHN_INDICES
  45
  46 class ELFFile(object):
  47     """ Creation: the constructor accepts a stream (file-like object) with the
  48         contents of an ELF file.
  49
  50         Optionally, a stream_loader function can be passed as the second
  51         argument. This stream_loader function takes a relative file path to
  52         load a supplementary object file, and returns a stream suitable for
  53         creating a new ELFFile. Currently, the only such relative file path is
  54         obtained from the supplementary object files.
  55
  56         Accessible attributes:
  57
  58             stream:
  59                 The stream holding the data of the file - must be a binary
  60                 stream (bytes, not string).
  61
  62             elfclass:
  63                 32 or 64 - specifies the word size of the target machine
  64
  65             little_endian:
  66                 boolean - specifies the target machine's endianness
  67
  68             elftype:
  69                 string or int, either known value of E_TYPE enum defining ELF
  70                 type (e.g. executable, dynamic library or core dump) or integral
  71                 unparsed value
  72
  73             header:
  74                 the complete ELF file header
  75
  76             e_ident_raw:
  77                 the raw e_ident field of the header
  78     """
  79     def __init__(self, stream, stream_loader=None):
  80         self.stream = stream
  81         self.stream.seek(0, io.SEEK_END)
  82         self.stream_len = self.stream.tell()
  83
  84         self._identify_file()
  85         self.structs = ELFStructs(
  86             little_endian=self.little_endian,
  87             elfclass=self.elfclass)
  88
  89         self.structs.create_basic_structs()
  90         self.header = self._parse_elf_header()
  91         self.structs.create_advanced_structs(
  92                 self['e_type'],
  93                 self['e_machine'],
  94                 self['e_ident']['EI_OSABI'])
  95         self.stream.seek(0)
  96         self.e_ident_raw = self.stream.read(16)
  97
  98         self._section_header_stringtable = \
  99             self._get_section_header_stringtable()
 100         self._section_name_map = None
 101         self.stream_loader = stream_loader
 102
 103     @classmethod
 104     def load_from_path(cls, path):
 105         """Takes a path to a file on the local filesystem, and returns an
 106         ELFFile from it, setting up a correct stream_loader relative to the
 107         original file.
 108         """
 109         base_directory = os.path.dirname(path)
 110         def loader(elf_path):
 111             # FIXME: use actual path instead of str/bytes
 112             if not os.path.isabs(elf_path):
 113                 elf_path = os.path.join(base_directory,
 114                                         elf_path)
 115             return open(elf_path, 'rb')
 116         stream = open(path, 'rb')
 117         return ELFFile(stream, loader)
 118
 119     def num_sections(self):
 120         """ Number of sections in the file
 121         """
 122         if self['e_shoff'] == 0:
 123             return 0
 124         # From the ELF ABI documentation at
 125         # https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.sheader.html:
 126         # "e_shnum normally tells how many entries the section header table
 127         # contains. [...] If the number of sections is greater than or equal to
 128         # SHN_LORESERVE (0xff00), e_shnum has the value SHN_UNDEF (0) and the
 129         # actual number of section header table entries is contained in the
 130         # sh_size field of the section header at index 0 (otherwise, the sh_size
 131         # member of the initial entry contains 0)."
 132         if self['e_shnum'] == 0:
 133             return self._get_section_header(0)['sh_size']
 134         return self['e_shnum']
 135
 136     def get_section(self, n):
 137         """ Get the section at index #n from the file (Section object or a
 138             subclass)
 139         """
 140         section_header = self._get_section_header(n)
 141         return self._make_section(section_header)
 142
 143     def get_section_by_name(self, name):
 144         """ Get a section from the file, by name. Return None if no such
 145             section exists.
 146         """
 147         # The first time this method is called, construct a name to number
 148         # mapping
 149         #
 150         if self._section_name_map is None:
 151             self._make_section_name_map()
 152         secnum = self._section_name_map.get(name, None)
 153         return None if secnum is None else self.get_section(secnum)
 154
 155     def get_section_index(self, section_name):
 156         """ Gets the index of the section by name. Return None if no such
 157             section name exists.
 158         """
 159         # The first time this method is called, construct a name to number
 160         # mapping
 161         #
 162         if self._section_name_map is None:
 163             self._make_section_name_map()
 164         return self._section_name_map.get(section_name, None)
 165
 166     def iter_sections(self, type=None):
 167         """ Yield all the sections in the file. If the optional |type|
 168             parameter is passed, this method will only yield sections of the
 169             given type. The parameter value must be a string containing the
 170             name of the type as defined in the ELF specification, e.g.
 171             'SHT_SYMTAB'.
 172         """
 173         for i in range(self.num_sections()):
 174             section = self.get_section(i)
 175             if type is None or section['sh_type'] == type:
 176                 yield section
 177
 178     def num_segments(self):
 179         """ Number of segments in the file
 180         """
 181         # From: https://github.com/hjl-tools/x86-psABI/wiki/X86-psABI
 182         # Section: 4.1.2 Number of Program Headers
 183         # If the number of program headers is greater than or equal to
 184         # PN_XNUM (0xffff), this member has the value PN_XNUM
 185         # (0xffff). The actual number of program header table entries
 186         # is contained in the sh_info field of the section header at
 187         # index 0.
 188         if self['e_phnum'] < 0xffff:
 189             return self['e_phnum']
 190         else:
 191             return self.get_section(0)['sh_info']
 192
 193     def get_segment(self, n):
 194         """ Get the segment at index #n from the file (Segment object)
 195         """
 196         segment_header = self._get_segment_header(n)
 197         return self._make_segment(segment_header)
 198
 199     def iter_segments(self, type=None):
 200         """ Yield all the segments in the file. If the optional |type|
 201             parameter is passed, this method will only yield segments of the
 202             given type. The parameter value must be a string containing the
 203             name of the type as defined in the ELF specification, e.g.
 204             'PT_LOAD'.
 205         """
 206         for i in range(self.num_segments()):
 207             segment = self.get_segment(i)
 208             if type is None or segment['p_type'] == type:
 209                 yield segment
 210
 211     def address_offsets(self, start, size=1):
 212         """ Yield a file offset for each ELF segment containing a memory region.
 213
 214             A memory region is defined by the range [start...start+size). The
 215             offset of the region is yielded.
 216         """
 217         end = start + size
 218         # consider LOAD only to prevent same address being yielded twice
 219         for seg in self.iter_segments(type='PT_LOAD'):
 220             if (start >= seg['p_vaddr'] and
 221                 end <= seg['p_vaddr'] + seg['p_filesz']):
 222                 yield start - seg['p_vaddr'] + seg['p_offset']
 223
 224     def has_dwarf_info(self):
 225         """ Check whether this file appears to have debugging information.
 226             We assume that if it has the .debug_info or .zdebug_info section, it
 227             has all the other required sections as well.
 228         """
 229         return bool(self.get_section_by_name('.debug_info') or
 230             self.get_section_by_name('.zdebug_info') or
 231             self.get_section_by_name('.eh_frame'))
 232
 233     def get_dwarf_info(self, relocate_dwarf_sections=True, follow_links=True):
 234         """ Return a DWARFInfo object representing the debugging information in
 235             this file.
 236
 237             If relocate_dwarf_sections is True, relocations for DWARF sections
 238             are looked up and applied.
 239
 240             If follow_links is True, we will try to load the supplementary
 241             object file (if any), and use it to resolve references and imports.
 242         """
 243         # Expect that has_dwarf_info was called, so at least .debug_info is
 244         # present.
 245         # Sections that aren't found will be passed as None to DWARFInfo.
 246
 247         section_names = ('.debug_info', '.debug_aranges', '.debug_abbrev',
 248                          '.debug_str', '.debug_line', '.debug_frame',
 249                          '.debug_loc', '.debug_ranges', '.debug_pubtypes',
 250                          '.debug_pubnames', '.debug_addr',
 251                          '.debug_str_offsets', '.debug_line_str',
 252                          '.debug_loclists', '.debug_rnglists',
 253                          '.debug_sup', '.gnu_debugaltlink')
 254
 255         compressed = bool(self.get_section_by_name('.zdebug_info'))
 256         if compressed:
 257             section_names = tuple(map(lambda x: '.z' + x[1:], section_names))
 258
 259         # As it is loaded in the process image, .eh_frame cannot be compressed
 260         section_names += ('.eh_frame', )
 261
 262         (debug_info_sec_name, debug_aranges_sec_name, debug_abbrev_sec_name,
 263          debug_str_sec_name, debug_line_sec_name, debug_frame_sec_name,
 264          debug_loc_sec_name, debug_ranges_sec_name, debug_pubtypes_name,
 265          debug_pubnames_name, debug_addr_name, debug_str_offsets_name,
 266          debug_line_str_name, debug_loclists_sec_name, debug_rnglists_sec_name,
 267          debug_sup_name, gnu_debugaltlink_name, eh_frame_sec_name) = section_names
 268
 269         debug_sections = {}
 270         for secname in section_names:
 271             section = self.get_section_by_name(secname)
 272             if section is None:
 273                 debug_sections[secname] = None
 274             else:
 275                 dwarf_section = self._read_dwarf_section(
 276                     section,
 277                     relocate_dwarf_sections)
 278                 if compressed and secname.startswith('.z'):
 279                     dwarf_section = self._decompress_dwarf_section(dwarf_section)
 280                 debug_sections[secname] = dwarf_section
 281
 282         # Lookup if we have any of the .gnu_debugaltlink (GNU proprietary
 283         # implementation) or .debug_sup sections, referencing a supplementary
 284         # DWARF file
 285
 286         dwarfinfo = DWARFInfo(
 287                 config=DwarfConfig(
 288                     little_endian=self.little_endian,
 289                     default_address_size=self.elfclass // 8,
 290                     machine_arch=self.get_machine_arch()),
 291                 debug_info_sec=debug_sections[debug_info_sec_name],
 292                 debug_aranges_sec=debug_sections[debug_aranges_sec_name],
 293                 debug_abbrev_sec=debug_sections[debug_abbrev_sec_name],
 294                 debug_frame_sec=debug_sections[debug_frame_sec_name],
 295                 eh_frame_sec=debug_sections[eh_frame_sec_name],
 296                 debug_str_sec=debug_sections[debug_str_sec_name],
 297                 debug_loc_sec=debug_sections[debug_loc_sec_name],
 298                 debug_ranges_sec=debug_sections[debug_ranges_sec_name],
 299                 debug_line_sec=debug_sections[debug_line_sec_name],
 300                 debug_pubtypes_sec=debug_sections[debug_pubtypes_name],
 301                 debug_pubnames_sec=debug_sections[debug_pubnames_name],
 302                 debug_addr_sec=debug_sections[debug_addr_name],
 303                 debug_str_offsets_sec=debug_sections[debug_str_offsets_name],
 304                 debug_line_str_sec=debug_sections[debug_line_str_name],
 305                 debug_loclists_sec=debug_sections[debug_loclists_sec_name],
 306                 debug_rnglists_sec=debug_sections[debug_rnglists_sec_name],
 307                 debug_sup_sec=debug_sections[debug_sup_name],
 308                 gnu_debugaltlink_sec=debug_sections[gnu_debugaltlink_name]
 309                 )
 310         if follow_links:
 311             dwarfinfo.supplementary_dwarfinfo = self.get_supplementary_dwarfinfo(dwarfinfo)
 312         return dwarfinfo
 313
 314
 315     def get_supplementary_dwarfinfo(self, dwarfinfo):
 316         """
 317         Read supplementary dwarfinfo, from either the standared .debug_sup
 318         section or the GNU proprietary .gnu_debugaltlink.
 319         """
 320         supfilepath = dwarfinfo.parse_debugsupinfo()
 321         if supfilepath is not None and self.stream_loader is not None:
 322             stream = self.stream_loader(supfilepath)
 323             supelffile = ELFFile(stream)
 324             dwarf_info = supelffile.get_dwarf_info()
 325             stream.close()
 326             return dwarf_info
 327         return None
 328
 329
 330     def has_ehabi_info(self):
 331         """ Check whether this file appears to have arm exception handler index table.
 332         """
 333         return any(self.iter_sections(type='SHT_ARM_EXIDX'))
 334
 335     def get_ehabi_infos(self):
 336         """ Generally, shared library and executable contain 1 .ARM.exidx section.
 337             Object file contains many .ARM.exidx sections.
 338             So we must traverse every section and filter sections whose type is SHT_ARM_EXIDX.
 339         """
 340         _ret = []
 341         if self['e_type'] == 'ET_REL':
 342             # TODO: support relocatable file
 343             assert False, "Current version of pyelftools doesn't support relocatable file."
 344         for section in self.iter_sections(type='SHT_ARM_EXIDX'):
 345             _ret.append(EHABIInfo(section, self.little_endian))
 346         return _ret if len(_ret) > 0 else None
 347
 348     def get_machine_arch(self):
 349         """ Return the machine architecture, as detected from the ELF header.
 350         """
 351         architectures = {
 352             'EM_M32'           : 'AT&T WE 32100',
 353             'EM_SPARC'         : 'SPARC',
 354             'EM_386'           : 'x86',
 355             'EM_68K'           : 'Motorola 68000',
 356             'EM_88K'           : 'Motorola 88000',
 357             'EM_IAMCU'         : 'Intel MCU',
 358             'EM_860'           : 'Intel 80860',
 359             'EM_MIPS'          : 'MIPS',
 360             'EM_S370'          : 'IBM System/370',
 361             'EM_MIPS_RS3_LE'   : 'MIPS RS3000 Little-endian',
 362             'EM_PARISC'        : 'Hewlett-Packard PA-RISC',
 363             'EM_VPP500'        : 'Fujitsu VPP500',
 364             'EM_SPARC32PLUS'   : 'Enhanced SPARC',
 365             'EM_960'           : 'Intel 80960',
 366             'EM_PPC'           : 'PowerPC',
 367             'EM_PPC64'         : '64-bit PowerPC',
 368             'EM_S390'          : 'IBM System/390',
 369             'EM_SPU'           : 'IBM SPU/SPC',
 370             'EM_V800'          : 'NEC V800',
 371             'EM_FR20'          : 'Fujitsu FR20',
 372             'EM_RH32'          : 'TRW RH-32',
 373             'EM_RCE'           : 'Motorola RCE',
 374             'EM_ARM'           : 'ARM',
 375             'EM_ALPHA'         : 'Digital Alpha',
 376             'EM_SH'            : 'Hitachi SH',
 377             'EM_SPARCV9'       : 'SPARC Version 9',
 378             'EM_TRICORE'       : 'Siemens TriCore embedded processor',
 379             'EM_ARC'           : 'Argonaut RISC Core, Argonaut Technologies Inc.',
 380             'EM_H8_300'        : 'Hitachi H8/300',
 381             'EM_H8_300H'       : 'Hitachi H8/300H',
 382             'EM_H8S'           : 'Hitachi H8S',
 383             'EM_H8_500'        : 'Hitachi H8/500',
 384             'EM_IA_64'         : 'Intel IA-64',
 385             'EM_MIPS_X'        : 'MIPS-X',
 386             'EM_COLDFIRE'      : 'Motorola ColdFire',
 387             'EM_68HC12'        : 'Motorola M68HC12',
 388             'EM_MMA'           : 'Fujitsu MMA',
 389             'EM_PCP'           : 'Siemens PCP',
 390             'EM_NCPU'          : 'Sony nCPU',
 391             'EM_NDR1'          : 'Denso NDR1',
 392             'EM_STARCORE'      : 'Motorola Star*Core',
 393             'EM_ME16'          : 'Toyota ME16',
 394             'EM_ST100'         : 'STMicroelectronics ST100',
 395             'EM_TINYJ'         : 'Advanced Logic TinyJ',
 396             'EM_X86_64'        : 'x64',
 397             'EM_PDSP'          : 'Sony DSP',
 398             'EM_PDP10'         : 'Digital Equipment PDP-10',
 399             'EM_PDP11'         : 'Digital Equipment PDP-11',
 400             'EM_FX66'          : 'Siemens FX66',
 401             'EM_ST9PLUS'       : 'STMicroelectronics ST9+ 8/16 bit',
 402             'EM_ST7'           : 'STMicroelectronics ST7 8-bit',
 403             'EM_68HC16'        : 'Motorola MC68HC16',
 404             'EM_68HC11'        : 'Motorola MC68HC11',
 405             'EM_68HC08'        : 'Motorola MC68HC08',
 406             'EM_68HC05'        : 'Motorola MC68HC05',
 407             'EM_SVX'           : 'Silicon Graphics SVx',
 408             'EM_ST19'          : 'STMicroelectronics ST19 8-bit',
 409             'EM_VAX'           : 'Digital VAX',
 410             'EM_CRIS'          : 'Axis Communications 32-bit',
 411             'EM_JAVELIN'       : 'Infineon Technologies 32-bit',
 412             'EM_FIREPATH'      : 'Element 14 64-bit DSP',
 413             'EM_ZSP'           : 'LSI Logic 16-bit DSP',
 414             'EM_MMIX'          : 'Donald Knuth\'s educational 64-bit',
 415             'EM_HUANY'         : 'Harvard University machine-independent object files',
 416             'EM_PRISM'         : 'SiTera Prism',
 417             'EM_AVR'           : 'Atmel AVR 8-bit',
 418             'EM_FR30'          : 'Fujitsu FR30',
 419             'EM_D10V'          : 'Mitsubishi D10V',
 420             'EM_D30V'          : 'Mitsubishi D30V',
 421             'EM_V850'          : 'NEC v850',
 422             'EM_M32R'          : 'Mitsubishi M32R',
 423             'EM_MN10300'       : 'Matsushita MN10300',
 424             'EM_MN10200'       : 'Matsushita MN10200',
 425             'EM_PJ'            : 'picoJava',
 426             'EM_OPENRISC'      : 'OpenRISC 32-bit',
 427             'EM_ARC_COMPACT'   : 'ARC International ARCompact',
 428             'EM_XTENSA'        : 'Tensilica Xtensa',
 429             'EM_VIDEOCORE'     : 'Alphamosaic VideoCore',
 430             'EM_TMM_GPP'       : 'Thompson Multimedia',
 431             'EM_NS32K'         : 'National Semiconductor 32000 series',
 432             'EM_TPC'           : 'Tenor Network TPC',
 433             'EM_SNP1K'         : 'Trebia SNP 1000',
 434             'EM_ST200'         : 'STMicroelectronics ST200',
 435             'EM_IP2K'          : 'Ubicom IP2xxx',
 436             'EM_MAX'           : 'MAX',
 437             'EM_CR'            : 'National Semiconductor CompactRISC',
 438             'EM_F2MC16'        : 'Fujitsu F2MC16',
 439             'EM_MSP430'        : 'Texas Instruments msp430',
 440             'EM_BLACKFIN'      : 'Analog Devices Blackfin',
 441             'EM_SE_C33'        : 'Seiko Epson S1C33',
 442             'EM_SEP'           : 'Sharp',
 443             'EM_ARCA'          : 'Arca RISC',
 444             'EM_UNICORE'       : 'PKU-Unity MPRC',
 445             'EM_EXCESS'        : 'eXcess',
 446             'EM_DXP'           : 'Icera Semiconductor Deep Execution Processor',
 447             'EM_ALTERA_NIOS2'  : 'Altera Nios II',
 448             'EM_CRX'           : 'National Semiconductor CompactRISC CRX',
 449             'EM_XGATE'         : 'Motorola XGATE',
 450             'EM_C166'          : 'Infineon C16x/XC16x',
 451             'EM_M16C'          : 'Renesas M16C',
 452             'EM_DSPIC30F'      : 'Microchip Technology dsPIC30F',
 453             'EM_CE'            : 'Freescale Communication Engine RISC core',
 454             'EM_M32C'          : 'Renesas M32C',
 455             'EM_TSK3000'       : 'Altium TSK3000',
 456             'EM_RS08'          : 'Freescale RS08',
 457             'EM_SHARC'         : 'Analog Devices SHARC',
 458             'EM_ECOG2'         : 'Cyan Technology eCOG2',
 459             'EM_SCORE7'        : 'Sunplus S+core7 RISC',
 460             'EM_DSP24'         : 'New Japan Radio (NJR) 24-bit DSP',
 461             'EM_VIDEOCORE3'    : 'Broadcom VideoCore III',
 462             'EM_LATTICEMICO32' : 'Lattice FPGA RISC',
 463             'EM_SE_C17'        : 'Seiko Epson C17',
 464             'EM_TI_C6000'      : 'TI TMS320C6000',
 465             'EM_TI_C2000'      : 'TI TMS320C2000',
 466             'EM_TI_C5500'      : 'TI TMS320C55x',
 467             'EM_TI_ARP32'      : 'TI Application Specific RISC, 32bit',
 468             'EM_TI_PRU'        : 'TI Programmable Realtime Unit',
 469             'EM_MMDSP_PLUS'    : 'STMicroelectronics 64bit VLIW',
 470             'EM_CYPRESS_M8C'   : 'Cypress M8C',
 471             'EM_R32C'          : 'Renesas R32C',
 472             'EM_TRIMEDIA'      : 'NXP Semiconductors TriMedia',
 473             'EM_QDSP6'         : 'QUALCOMM DSP6',
 474             'EM_8051'          : 'Intel 8051',
 475             'EM_STXP7X'        : 'STMicroelectronics STxP7x',
 476             'EM_NDS32'         : 'Andes Technology RISC',
 477             'EM_ECOG1'         : 'Cyan Technology eCOG1X',
 478             'EM_ECOG1X'        : 'Cyan Technology eCOG1X',
 479             'EM_MAXQ30'        : 'Dallas Semiconductor MAXQ30',
 480             'EM_XIMO16'        : 'New Japan Radio (NJR) 16-bit',
 481             'EM_MANIK'         : 'M2000 Reconfigurable RISC',
 482             'EM_CRAYNV2'       : 'Cray Inc. NV2',
 483             'EM_RX'            : 'Renesas RX',
 484             'EM_METAG'         : 'Imagination Technologies META',
 485             'EM_MCST_ELBRUS'   : 'MCST Elbrus',
 486             'EM_ECOG16'        : 'Cyan Technology eCOG16',
 487             'EM_CR16'          : 'National Semiconductor CompactRISC CR16 16-bit',
 488             'EM_ETPU'          : 'Freescale',
 489             'EM_SLE9X'         : 'Infineon Technologies SLE9X',
 490             'EM_L10M'          : 'Intel L10M',
 491             'EM_K10M'          : 'Intel K10M',
 492             'EM_AARCH64'       : 'AArch64',
 493             'EM_AVR32'         : 'Atmel 32-bit',
 494             'EM_STM8'          : 'STMicroeletronics STM8 8-bit',
 495             'EM_TILE64'        : 'Tilera TILE64',
 496             'EM_TILEPRO'       : 'Tilera TILEPro',
 497             'EM_MICROBLAZE'    : 'Xilinx MicroBlaze 32-bit RISC',
 498             'EM_CUDA'          : 'NVIDIA CUDA',
 499             'EM_TILEGX'        : 'Tilera TILE-Gx',
 500             'EM_CLOUDSHIELD'   : 'CloudShield',
 501             'EM_COREA_1ST'     : 'KIPO-KAIST Core-A 1st generation',
 502             'EM_COREA_2ND'     : 'KIPO-KAIST Core-A 2nd generation',
 503             'EM_ARC_COMPACT2'  : 'Synopsys ARCompact V2',
 504             'EM_OPEN8'         : 'Open8 8-bit RISC',
 505             'EM_RL78'          : 'Renesas RL78',
 506             'EM_VIDEOCORE5'    : 'Broadcom VideoCore V',
 507             'EM_78KOR'         : 'Renesas 78KOR',
 508             'EM_56800EX'       : 'Freescale 56800EX',
 509             'EM_BA1'           : 'Beyond BA1',
 510             'EM_BA2'           : 'Beyond BA2',
 511             'EM_XCORE'         : 'XMOS xCORE',
 512             'EM_MCHP_PIC'      : 'Microchip 8-bit PIC',
 513             'EM_INTEL205'      : 'Reserved by Intel',
 514             'EM_INTEL206'      : 'Reserved by Intel',
 515             'EM_INTEL207'      : 'Reserved by Intel',
 516             'EM_INTEL208'      : 'Reserved by Intel',
 517             'EM_INTEL209'      : 'Reserved by Intel',
 518             'EM_KM32'          : 'KM211 KM32 32-bit',
 519             'EM_KMX32'         : 'KM211 KMX32 32-bit',
 520             'EM_KMX16'         : 'KM211 KMX16 16-bit',
 521             'EM_KMX8'          : 'KM211 KMX8 8-bit',
 522             'EM_KVARC'         : 'KM211 KVARC',
 523             'EM_CDP'           : 'Paneve CDP',
 524             'EM_COGE'          : 'Cognitive',
 525             'EM_COOL'          : 'Bluechip Systems CoolEngine',
 526             'EM_NORC'          : 'Nanoradio Optimized RISC',
 527             'EM_CSR_KALIMBA'   : 'CSR Kalimba',
 528             'EM_Z80'           : 'Zilog Z80',
 529             'EM_VISIUM'        : 'VISIUMcore',
 530             'EM_FT32'          : 'FTDI Chip FT32 32-bit RISC',
 531             'EM_MOXIE'         : 'Moxie',
 532             'EM_AMDGPU'        : 'AMD GPU',
 533             'EM_RISCV'         : 'RISC-V',
 534             'EM_BPF'           : 'Linux BPF - in-kernel virtual machine',
 535             'EM_CSKY'          : 'C-SKY',
 536             'EM_FRV'           : 'Fujitsu FR-V'
 537         }
 538
 539         return architectures.get(self['e_machine'], '<unknown>')
 540
 541     def get_shstrndx(self):
 542         """ Find the string table section index for the section header table
 543         """
 544         # From https://refspecs.linuxfoundation.org/elf/gabi4+/ch4.eheader.html:
 545         # If the section name string table section index is greater than or
 546         # equal to SHN_LORESERVE (0xff00), this member has the value SHN_XINDEX
 547         # (0xffff) and the actual index of the section name string table section
 548         # is contained in the sh_link field of the section header at index 0.
 549         if self['e_shstrndx'] != SHN_INDICES.SHN_XINDEX:
 550             return self['e_shstrndx']
 551         else:
 552             return self._get_section_header(0)['sh_link']
 553
 554     #-------------------------------- PRIVATE --------------------------------#
 555
 556     def __getitem__(self, name):
 557         """ Implement dict-like access to header entries
 558         """
 559         return self.header[name]
 560
 561     def _identify_file(self):
 562         """ Verify the ELF file and identify its class and endianness.
 563         """
 564         # Note: this code reads the stream directly, without using ELFStructs,
 565         # since we don't yet know its exact format. ELF was designed to be
 566         # read like this - its e_ident field is word-size and endian agnostic.
 567         self.stream.seek(0)
 568         magic = self.stream.read(4)
 569         elf_assert(magic == b'\x7fELF', 'Magic number does not match')
 570
 571         ei_class = self.stream.read(1)
 572         if ei_class == b'\x01':
 573             self.elfclass = 32
 574         elif ei_class == b'\x02':
 575             self.elfclass = 64
 576         else:
 577             raise ELFError('Invalid EI_CLASS %s' % repr(ei_class))
 578
 579         ei_data = self.stream.read(1)
 580         if ei_data == b'\x01':
 581             self.little_endian = True
 582         elif ei_data == b'\x02':
 583             self.little_endian = False
 584         else:
 585             raise ELFError('Invalid EI_DATA %s' % repr(ei_data))
 586
 587     def _section_offset(self, n):
 588         """ Compute the offset of section #n in the file
 589         """
 590         return self['e_shoff'] + n * self['e_shentsize']
 591
 592     def _segment_offset(self, n):
 593         """ Compute the offset of segment #n in the file
 594         """
 595         return self['e_phoff'] + n * self['e_phentsize']
 596
 597     def _make_segment(self, segment_header):
 598         """ Create a Segment object of the appropriate type
 599         """
 600         segtype = segment_header['p_type']
 601         if segtype == 'PT_INTERP':
 602             return InterpSegment(segment_header, self.stream)
 603         elif segtype == 'PT_DYNAMIC':
 604             return DynamicSegment(segment_header, self.stream, self)
 605         elif segtype == 'PT_NOTE':
 606             return NoteSegment(segment_header, self.stream, self)
 607         else:
 608             return Segment(segment_header, self.stream)
 609
 610     def _get_section_header(self, n):
 611         """ Find the header of section #n, parse it and return the struct
 612         """
 613
 614         stream_pos = self._section_offset(n)
 615         if stream_pos > self.stream_len:
 616             return None
 617
 618         return struct_parse(
 619             self.structs.Elf_Shdr,
 620             self.stream,
 621             stream_pos=stream_pos)
 622
 623     def _get_section_name(self, section_header):
 624         """ Given a section header, find this section's name in the file's
 625             string table
 626         """
 627         if self._section_header_stringtable is None:
 628             raise ELFParseError("String Table not found")
 629
 630         name_offset = section_header['sh_name']
 631         return self._section_header_stringtable.get_string(name_offset)
 632
 633     def _make_section(self, section_header):
 634         """ Create a section object of the appropriate type
 635         """
 636         name = self._get_section_name(section_header)
 637         sectype = section_header['sh_type']
 638
 639         if sectype == 'SHT_STRTAB':
 640             return StringTableSection(section_header, name, self)
 641         elif sectype == 'SHT_NULL':
 642             return NullSection(section_header, name, self)
 643         elif sectype in ('SHT_SYMTAB', 'SHT_DYNSYM', 'SHT_SUNW_LDYNSYM'):
 644             return self._make_symbol_table_section(section_header, name)
 645         elif sectype == 'SHT_SYMTAB_SHNDX':
 646             return self._make_symbol_table_index_section(section_header, name)
 647         elif sectype == 'SHT_SUNW_syminfo':
 648             return self._make_sunwsyminfo_table_section(section_header, name)
 649         elif sectype == 'SHT_GNU_verneed':
 650             return self._make_gnu_verneed_section(section_header, name)
 651         elif sectype == 'SHT_GNU_verdef':
 652             return self._make_gnu_verdef_section(section_header, name)
 653         elif sectype == 'SHT_GNU_versym':
 654             return self._make_gnu_versym_section(section_header, name)
 655         elif sectype in ('SHT_REL', 'SHT_RELA'):
 656             return RelocationSection(section_header, name, self)
 657         elif sectype == 'SHT_DYNAMIC':
 658             return DynamicSection(section_header, name, self)
 659         elif sectype == 'SHT_NOTE':
 660             return NoteSection(section_header, name, self)
 661         elif sectype == 'SHT_PROGBITS' and name == '.stab':
 662             return StabSection(section_header, name, self)
 663         elif sectype == 'SHT_ARM_ATTRIBUTES':
 664             return ARMAttributesSection(section_header, name, self)
 665         elif sectype == 'SHT_HASH':
 666             return self._make_elf_hash_section(section_header, name)
 667         elif sectype == 'SHT_GNU_HASH':
 668             return self._make_gnu_hash_section(section_header, name)
 669         elif sectype == 'SHT_RELR':
 670             return RelrRelocationSection(section_header, name, self)
 671         else:
 672             return Section(section_header, name, self)
 673
 674     def _make_section_name_map(self):
 675         self._section_name_map = {}
 676         for i, sec in enumerate(self.iter_sections()):
 677             self._section_name_map[sec.name] = i
 678
 679     def _make_symbol_table_section(self, section_header, name):
 680         """ Create a SymbolTableSection
 681         """
 682         linked_strtab_index = section_header['sh_link']
 683         strtab_section = self.get_section(linked_strtab_index)
 684         return SymbolTableSection(
 685             section_header, name,
 686             elffile=self,
 687             stringtable=strtab_section)
 688
 689     def _make_symbol_table_index_section(self, section_header, name):
 690         """ Create a SymbolTableIndexSection object
 691         """
 692         linked_symtab_index = section_header['sh_link']
 693         return SymbolTableIndexSection(
 694             section_header, name, elffile=self,
 695             symboltable=linked_symtab_index)
 696
 697     def _make_sunwsyminfo_table_section(self, section_header, name):
 698         """ Create a SUNWSyminfoTableSection
 699         """
 700         linked_strtab_index = section_header['sh_link']
 701         strtab_section = self.get_section(linked_strtab_index)
 702         return SUNWSyminfoTableSection(
 703             section_header, name,
 704             elffile=self,
 705             symboltable=strtab_section)
 706
 707     def _make_gnu_verneed_section(self, section_header, name):
 708         """ Create a GNUVerNeedSection
 709         """
 710         linked_strtab_index = section_header['sh_link']
 711         strtab_section = self.get_section(linked_strtab_index)
 712         return GNUVerNeedSection(
 713             section_header, name,
 714             elffile=self,
 715             stringtable=strtab_section)
 716
 717     def _make_gnu_verdef_section(self, section_header, name):
 718         """ Create a GNUVerDefSection
 719         """
 720         linked_strtab_index = section_header['sh_link']
 721         strtab_section = self.get_section(linked_strtab_index)
 722         return GNUVerDefSection(
 723             section_header, name,
 724             elffile=self,
 725             stringtable=strtab_section)
 726
 727     def _make_gnu_versym_section(self, section_header, name):
 728         """ Create a GNUVerSymSection
 729         """
 730         linked_strtab_index = section_header['sh_link']
 731         strtab_section = self.get_section(linked_strtab_index)
 732         return GNUVerSymSection(
 733             section_header, name,
 734             elffile=self,
 735             symboltable=strtab_section)
 736
 737     def _make_elf_hash_section(self, section_header, name):
 738         linked_symtab_index = section_header['sh_link']
 739         symtab_section = self.get_section(linked_symtab_index)
 740         return ELFHashSection(
 741             section_header, name, self, symtab_section
 742         )
 743
 744     def _make_gnu_hash_section(self, section_header, name):
 745         linked_symtab_index = section_header['sh_link']
 746         symtab_section = self.get_section(linked_symtab_index)
 747         return GNUHashSection(
 748             section_header, name, self, symtab_section
 749         )
 750
 751     def _get_segment_header(self, n):
 752         """ Find the header of segment #n, parse it and return the struct
 753         """
 754         return struct_parse(
 755             self.structs.Elf_Phdr,
 756             self.stream,
 757             stream_pos=self._segment_offset(n))
 758
 759     def _get_section_header_stringtable(self):
 760         """ Get the string table section corresponding to the section header
 761             table.
 762         """
 763         stringtable_section_num = self.get_shstrndx()
 764
 765         stringtable_section_header = self._get_section_header(stringtable_section_num)
 766         if stringtable_section_header is None:
 767             return None
 768
 769         return StringTableSection(
 770                 header=stringtable_section_header,
 771                 name='',
 772                 elffile=self)
 773
 774     def _parse_elf_header(self):
 775         """ Parses the ELF file header and assigns the result to attributes
 776             of this object.
 777         """
 778         return struct_parse(self.structs.Elf_Ehdr, self.stream, stream_pos=0)
 779
 780     def _read_dwarf_section(self, section, relocate_dwarf_sections):
 781         """ Read the contents of a DWARF section from the stream and return a
 782             DebugSectionDescriptor. Apply relocations if asked to.
 783         """
 784         # The section data is read into a new stream, for processing
 785         section_stream = BytesIO()
 786         section_stream.write(section.data())
 787
 788         if relocate_dwarf_sections:
 789             reloc_handler = RelocationHandler(self)
 790             reloc_section = reloc_handler.find_relocations_for_section(section)
 791             if reloc_section is not None:
 792                 reloc_handler.apply_section_relocations(
 793                         section_stream, reloc_section)
 794
 795         return DebugSectionDescriptor(
 796                 stream=section_stream,
 797                 name=section.name,
 798                 global_offset=section['sh_offset'],
 799                 size=section.data_size,
 800                 address=section['sh_addr'])
 801
 802     @staticmethod
 803     def _decompress_dwarf_section(section):
 804         """ Returns the uncompressed contents of the provided DWARF section.
 805         """
 806         # TODO: support other compression formats from readelf.c
 807         assert section.size > 12, 'Unsupported compression format.'
 808
 809         section.stream.seek(0)
 810         # According to readelf.c the content should contain "ZLIB"
 811         # followed by the uncompressed section size - 8 bytes in
 812         # big-endian order
 813         compression_type = section.stream.read(4)
 814         assert compression_type == b'ZLIB', \
 815             'Invalid compression type: %r' % (compression_type)
 816
 817         uncompressed_size = struct.unpack('>Q', section.stream.read(8))[0]
 818
 819         decompressor = zlib.decompressobj()
 820         uncompressed_stream = BytesIO()
 821         while True:
 822             chunk = section.stream.read(PAGESIZE)
 823             if not chunk:
 824                 break
 825             uncompressed_stream.write(decompressor.decompress(chunk))
 826         uncompressed_stream.write(decompressor.flush())
 827
 828         uncompressed_stream.seek(0, io.SEEK_END)
 829         size = uncompressed_stream.tell()
 830         assert uncompressed_size == size, \
 831                 'Wrong uncompressed size: expected %r, but got %r' % (
 832                     uncompressed_size, size,
 833                 )
 834
 835         return section._replace(stream=uncompressed_stream, size=size)
 836
 837     def close(self):
 838         self.stream.close()
 839
 840     def __enter__(self):
 841         return self
 842
 843     def __exit__(self, type, value, traceback):
 844         self.close()