The Tor Browser: python/mozbuild/mozpack/executables.py@925c144e1f1f (annotated)

python/mozbuild/mozpack/executables.py@925c144e1f1f (annotated)

python/mozbuild/mozpack/executables.py

Fri, 16 Jan 2015 18:13:44 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 18:13:44 +0100
branch: TOR_BUG_9701
changeset 14: 925c144e1f1f
permissions: -rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 import os
 import struct
 import subprocess
 from mozpack.errors import errors
 MACHO_SIGNATURES = [
 xfeedface,  # mach-o 32-bits big endian
 xcefaedfe,  # mach-o 32-bits little endian
 xfeedfacf,  # mach-o 64-bits big endian
 xcffaedfe,  # mach-o 64-bits little endian
 ]
 FAT_SIGNATURE = 0xcafebabe  # mach-o FAT binary
 ELF_SIGNATURE = 0x7f454c46  # Elf binary
 UNKNOWN = 0
 MACHO = 1
 ELF = 2
 def get_type(path):
     '''
     Check the signature of the give file and returns what kind of executable
     matches.
     '''
     with open(path, 'rb') as f:
         signature = f.read(4)
         if len(signature) < 4:
             return UNKNOWN
         signature = struct.unpack('>L', signature)[0]
         if signature == ELF_SIGNATURE:
             return ELF
         if signature in MACHO_SIGNATURES:
             return MACHO
         if signature != FAT_SIGNATURE:
             return UNKNOWN
         # We have to sanity check the second four bytes, because Java class
         # files use the same magic number as Mach-O fat binaries.
         # This logic is adapted from file(1), which says that Mach-O uses
         # these bytes to count the number of architectures within, while
         # Java uses it for a version number. Conveniently, there are only
         # 18 labelled Mach-O architectures, and Java's first released
         # class format used the version 43.0.
         num = f.read(4)
         if len(num) < 4:
             return UNKNOWN
         num = struct.unpack('>L', num)[0]
         if num < 20:
             return MACHO
         return UNKNOWN
 def is_executable(path):
     '''
     Return whether a given file path points to an executable or a library,
     where an executable or library is identified by:
         - the file extension on OS/2 and WINNT
         - the file signature on OS/X and ELF systems (GNU/Linux, Android, BSD,
           Solaris)
     As this function is intended for use to choose between the ExecutableFile
     and File classes in FileFinder, and choosing ExecutableFile only matters
     on OS/2, OS/X, ELF and WINNT (in GCC build) systems, we don't bother
     detecting other kind of executables.
     '''
     from buildconfig import substs
     if not os.path.exists(path):
         return False
     if substs['OS_ARCH'] == 'WINNT':
         return path.lower().endswith((substs['DLL_SUFFIX'],
                                       substs['BIN_SUFFIX']))
     return get_type(path) != UNKNOWN
 def may_strip(path):
     '''
     Return whether strip() should be called
     '''
     from buildconfig import substs
     return not substs['PKG_SKIP_STRIP']
 def strip(path):
     '''
     Execute the STRIP command with STRIP_FLAGS on the given path.
     '''
     from buildconfig import substs
     strip = substs['STRIP']
     flags = substs['STRIP_FLAGS'].split() if 'STRIP_FLAGS' in substs else []
     cmd = [strip] + flags + [path]
     if subprocess.call(cmd) != 0:
         errors.fatal('Error executing ' + ' '.join(cmd))
 def may_elfhack(path):
     '''
     Return whether elfhack() should be called
     '''
     # elfhack only supports libraries. We should check the ELF header for
     # the right flag, but checking the file extension works too.
     from buildconfig import substs
     return 'USE_ELF_HACK' in substs and substs['USE_ELF_HACK'] and \
            path.endswith(substs['DLL_SUFFIX'])
 def elfhack(path):
     '''
     Execute the elfhack command on the given path.
     '''
     from buildconfig import topobjdir
     cmd = [os.path.join(topobjdir, 'build/unix/elfhack/elfhack'), path]
     if 'ELF_HACK_FLAGS' in os.environ:
         cmd[1:0] = os.environ['ELF_HACK_FLAGS'].split()
     if subprocess.call(cmd) != 0:
         errors.fatal('Error executing ' + ' '.join(cmd))

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