import ctypes
import ctypes.wintypes
kernel32 = ctypes.wintypes.windll.kernel32
# Various access flag definitions:
class Access:
    DELETE      = 0x00010000
    READ_CONTROL= 0x00020000
    SYNCHRONIZE = 0x00100000
    WRITE_DAC   = 0x00040000
    WRITE_OWNER = 0x00080000
    PROCESS_VM_WRITE = 0x0020
    PROCESS_VM_READ = 0x0010
    PROCESS_VM_OPERATION = 0x0008
    PROCESS_TERMINATE = 0x0001
    PROCESS_SUSPEND_RESUME = 0x0800
    PROCESS_SET_QUOTA = 0x0100
    PROCESS_SET_INFORMATION = 0x0200
    PROCESS_QUERY_LIMITED_INFORMATION = 0x1000
    PROCESS_QUERY_INFORMATION = 0x0400
    PROCESS_DUP_HANDLE = 0x0040
    PROCESS_CREATE_THREAD = 0x0002
    PROCESS_CREATE_PROCESS = 0x0080
def read_process_mem(pid, address, size):
    """Read memory of the specified process ID."""
    buf = ctypes.create_string_buffer(size)
    gotBytes = ctypes.c_ulong(0)
    h = kernel32.OpenProcess(Access.PROCESS_VM_READ, False, pid)
    try:
        if kernel32.ReadProcessMemory(h, address, buf, size, ctypes.byref(gotBytes)):
            return buf
        else:
            # TODO: report appropriate error GetLastError
            raise Exception("Failed to access process memory.")
    finally:
        kernel32.CloseHandle(h)