Class CPUID

numexpr3/cpuinfo.py:584–1096

class CPUID(object):
	def __init__(self):
		# Figure out if SE Linux is on and in enforcing mode
		self.is_selinux_enforcing = False

		# Just return if the SE Linux Status Tool is not installed
		if not DataSource.has_sestatus():
			return

		# Figure out if we can execute heap and execute memory
		can_selinux_exec_heap = DataSource.sestatus_allow_execheap()
		can_selinux_exec_memory = DataSource.sestatus_allow_execmem()
		self.is_selinux_enforcing = (not can_selinux_exec_heap or not can_selinux_exec_memory)

	def _asm_func(self, restype=None, argtypes=(), byte_code=[]):
		byte_code = bytes.join(b'', byte_code)
		address = None

		if DataSource.is_windows:
			# Allocate a memory segment the size of the byte code, and make it executable
			size = len(byte_code)
			MEM_COMMIT = ctypes.c_ulong(0x1000)
			PAGE_EXECUTE_READWRITE = ctypes.c_ulong(0x40)
			address = ctypes.windll.kernel32.VirtualAlloc(ctypes.c_int(0), ctypes.c_size_t(size), MEM_COMMIT, PAGE_EXECUTE_READWRITE)
			if not address:
				raise Exception("Failed to VirtualAlloc")

			# Copy the byte code into the memory segment
			memmove = ctypes.CFUNCTYPE(ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_size_t)(ctypes._memmove_addr)
			if memmove(address, byte_code, size) < 0:
				raise Exception("Failed to memmove")
		else:
			# Allocate a memory segment the size of the byte code
			size = len(byte_code)
			address = ctypes.pythonapi.valloc(size)
			if not address:
				raise Exception("Failed to valloc")

			# Mark the memory segment as writeable only
			if not self.is_selinux_enforcing:
				WRITE = 0x2
				if ctypes.pythonapi.mprotect(address, size, WRITE) < 0:
					raise Exception("Failed to mprotect")

			# Copy the byte code into the memory segment
			if ctypes.pythonapi.memmove(address, byte_code, size) < 0:
				raise Exception("Failed to memmove")

			# Mark the memory segment as writeable and executable only
			if not self.is_selinux_enforcing:
				WRITE_EXECUTE = 0x2 | 0x4
				if ctypes.pythonapi.mprotect(address, size, WRITE_EXECUTE) < 0:
					raise Exception("Failed to mprotect")

		# Cast the memory segment into a function
		functype = ctypes.CFUNCTYPE(restype, *argtypes)
		fun = functype(address)
		return fun, address