tools/set_abi_version.py

   1 #!/usr/bin/python
   2 # Copyright 2008, Google Inc.
   3 # All rights reserved.
   4 #
   5 # Redistribution and use in source and binary forms, with or without
   6 # modification, are permitted provided that the following conditions are
   7 # met:
   8 #
   9 #     * Redistributions of source code must retain the above copyright
  10 # notice, this list of conditions and the following disclaimer.
  11 #     * Redistributions in binary form must reproduce the above
  12 # copyright notice, this list of conditions and the following disclaimer
  13 # in the documentation and/or other materials provided with the
  14 # distribution.
  15 #     * Neither the name of Google Inc. nor the names of its
  16 # contributors may be used to endorse or promote products derived from
  17 # this software without specific prior written permission.
  18 #
  19 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30
  31
  32 import getopt
  33 import sys
  34
  35
  36 """Changes the OS ABI number of Native Client executables.
  37
  38 This module contains code for updating the OS ABI version number of
  39 Native Client executables.  This is needed, for example, for changing
  40 the bad executables checked into the service runtime test data
  41 directory -- those executables were the result of hand editing of ELF
  42 headers, since such bad executables cannot be created with our
  43 toolchain.
  44
  45 """
  46
  47 ELF_ABIVERSION_OFFSET = 8
  48
  49
  50 def SetOsAbiVersion(elf_file_data, version):
  51   """Change the OS ABI number of a string, interpreted as an NaCl executable.
  52
  53   Args:
  54     elf_file_data: the ELF NaCl executable (as a string)
  55     version: the desired version number (as an integer)
  56
  57   Returns:
  58     Updated ELF NaCl executable.
  59   """
  60   return (elf_file_data[:ELF_ABIVERSION_OFFSET]
  61           + chr(version) + elf_file_data[ELF_ABIVERSION_OFFSET + 1:])
  62 #enddef
  63
  64
  65 def ModifyFileOsAbiVersion(filename, version):
  66   """Changes the OS ABI number of the named file.
  67
  68   No sanity checking is done on the file's contents to verify that it
  69   indeed is an ELF NaCl executable.
  70
  71   Args:
  72     filename: the file to be modified.
  73     version: the new OS ABI version number.
  74
  75   Returns:  nothing.
  76
  77   Throws: IOError if file does not exist or cannot be written.
  78
  79   """
  80   file_data = open(filename, 'rb').read()
  81   open(filename, 'wb').write(SetOsAbiVersion(file_data, version))
  82 # enddef
  83
  84
  85 def ReadFileOsAbiVersion(filename):
  86   """Read the named ELF NaCl executable and return its OS ABI version number.
  87
  88   Args:
  89     filename:  the file from which the OS ABI number is extracted.
  90
  91   Returns:
  92     The OS ABI version number (as an integer).
  93   """
  94   return ord(open(filename, 'rb').read()[ELF_ABIVERSION_OFFSET])
  95 #enddef
  96
  97
  98 def main(argv):
  99   abi_version = -1
 100   try:
 101     (opts, args) = getopt.getopt(argv[1:], 'v:')
 102   except getopt.error, e:
 103     print >>sys.stderr, str(e)
 104     print >>sys.stderr, 'Usage: set_abi_version [-v version_num] filename...'
 105     return 1
 106   # endtry
 107   for opt, val in opts:
 108     if opt == 'v':
 109       abi_version = int(val)
 110     # endif
 111   # endfor
 112
 113   for filename in args:
 114     if abi_version == -1:
 115       new_abi = 1 + ReadFileOsAbiVersion(filename)
 116     else:
 117       new_abi = abi_version
 118     # endif
 119
 120     ModifyFileOsAbiVersion(filename, new_abi)
 121   # endfor
 122
 123   return 0
 124 # enddef
 125
 126 if __name__ == '__main__':
 127   sys.exit(main(sys.argv))
 128 # endif