gecko/python/mozbuild/mozpack/executables.py

122 lines
3.8 KiB
Python

# 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 = [
0xfeedface, # mach-o 32-bits big endian
0xcefaedfe, # mach-o 32-bits little endian
0xfeedfacf, # mach-o 64-bits big endian
0xcffaedfe, # 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))