def write(self, fileobj):
fileobj = fileview(fileobj, self.offset, self.size)
fileobj.seek(0)
# serialize all the mach-o commands
self.synchronize_size()
self.header.to_fileobj(fileobj)
for lc, cmd, data in self.commands:
lc.to_fileobj(fileobj)
cmd.to_fileobj(fileobj)
if isinstance(data, unicode):
fileobj.write(data.encode(sys.getfilesystemencoding()))
elif isinstance(data, (bytes, str)):
fileobj.write(data)
else:
# segments..
for obj in data:
obj.to_fileobj(fileobj)
# zero out the unused space, doubt this is strictly necessary
# and is generally probably already the case
fileobj.write(B('\x00') * (self.low_offset - fileobj.tell()))
def rewriteDataForCommand(self, idx, data):
lc, cmd, old_data = self.commands[idx]
hdrsize = sizeof(lc.__class__) + sizeof(cmd.__class__)
align = struct.calcsize('L')
data = data + (B('\x00') * (align - (len(data) % align)))
newsize = hdrsize + len(data)
self.commands[idx] = (lc, cmd, data)
self.changedHeaderSizeBy(newsize - lc.cmdsize)
lc.cmdsize, cmd.name = newsize, hdrsize
return True
def walkRelocatables(self, shouldRelocateCommand=_shouldRelocateCommand):
"""
for all relocatable commands
yield (command_index, command_name, filename)
"""
for (idx, (lc, cmd, data)) in enumerate(self.commands):
if shouldRelocateCommand(lc.cmd):
name = _RELOCATABLE_NAMES[lc.cmd]
ofs = cmd.name - sizeof(lc.__class__) - sizeof(cmd.__class__)
yield idx, name, data[ofs:data.find(B('\x00'), ofs)].decode(
sys.getfilesystemencoding())
def readSymbolTable(self, fh):
cmd = self.symtab
fh.seek(cmd.stroff)
strtab = fh.read(cmd.strsize)
fh.seek(cmd.symoff)
nlists = []
for i in xrange(cmd.nsyms):
cmd = nlist.from_fileobj(fh)
if cmd.n_un == 0:
nlists.append((cmd, ''))
else:
nlists.append((cmd, strtab[cmd.n_un:strtab.find(B('\x00'), cmd.n_un)]))
self.nlists = nlists
def _formatinfo(format):
"""
Calculate the size and number of items in a struct format.
"""
size = struct.calcsize(format)
return size, len(struct.unpack(format, B('\x00') * size))