# Copyright (c) 2009-2014, gevent contributors # Based on eventlet.backdoor Copyright (c) 2005-2006, Bob Ippolito """ Interactive greenlet-based network console that can be used in any process. The :class:`BackdoorServer` provides a REPL inside a running process. As long as the process is monkey-patched, the ``BackdoorServer`` can coexist with other elements of the process. .. seealso:: :class:`code.InteractiveConsole` """ from __future__ import print_function, absolute_import import sys import socket from code import InteractiveConsole from gevent.greenlet import Greenlet from gevent.hub import getcurrent from gevent.server import StreamServer from gevent.pool import Pool __all__ = [ 'BackdoorServer', ] try: sys.ps1 except AttributeError: sys.ps1 = '>>> ' try: sys.ps2 except AttributeError: sys.ps2 = '... ' class _Greenlet_stdreplace(Greenlet): # A greenlet that replaces sys.std[in/out/err] while running. __slots__ = ( 'stdin', 'stdout', 'prev_stdin', 'prev_stdout', 'prev_stderr', ) def __init__(self, *args, **kwargs): Greenlet.__init__(self, *args, **kwargs) self.stdin = None self.stdout = None self.prev_stdin = None self.prev_stdout = None self.prev_stderr = None def switch(self, *args, **kw): if self.stdin is not None: self.switch_in() Greenlet.switch(self, *args, **kw) def switch_in(self): self.prev_stdin = sys.stdin self.prev_stdout = sys.stdout self.prev_stderr = sys.stderr sys.stdin = self.stdin sys.stdout = self.stdout sys.stderr = self.stdout def switch_out(self): sys.stdin = self.prev_stdin sys.stdout = self.prev_stdout sys.stderr = self.prev_stderr self.prev_stdin = self.prev_stdout = self.prev_stderr = None def throw(self, *args, **kwargs): # pylint:disable=arguments-differ if self.prev_stdin is None and self.stdin is not None: self.switch_in() Greenlet.throw(self, *args, **kwargs) def run(self): try: return Greenlet.run(self) finally: # Make sure to restore the originals. self.switch_out() class BackdoorServer(StreamServer): """ Provide a backdoor to a program for debugging purposes. .. warning:: This backdoor provides no authentication and makes no attempt to limit what remote users can do. Anyone that can access the server can take any action that the running python process can. Thus, while you may bind to any interface, for security purposes it is recommended that you bind to one only accessible to the local machine, e.g., 127.0.0.1/localhost. Basic usage:: from gevent.backdoor import BackdoorServer server = BackdoorServer(('127.0.0.1', 5001), banner="Hello from gevent backdoor!", locals={'foo': "From defined scope!"}) server.serve_forever() In a another terminal, connect with...:: $ telnet 127.0.0.1 5001 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. Hello from gevent backdoor! >> print(foo) From defined scope! .. versionchanged:: 1.2a1 Spawned greenlets are now tracked in a pool and killed when the server is stopped. """ def __init__(self, listener, locals=None, banner=None, **server_args): """ :keyword locals: If given, a dictionary of "builtin" values that will be available at the top-level. :keyword banner: If geven, a string that will be printed to each connecting user. """ group = Pool(greenlet_class=_Greenlet_stdreplace) # no limit on number StreamServer.__init__(self, listener, spawn=group, **server_args) _locals = {'__doc__': None, '__name__': '__console__'} if locals: _locals.update(locals) self.locals = _locals self.banner = banner self.stderr = sys.stderr def _create_interactive_locals(self): # Create and return a *new* locals dictionary based on self.locals, # and set any new entries in it. (InteractiveConsole does not # copy its locals value) _locals = self.locals.copy() # __builtins__ may either be the __builtin__ module or # __builtin__.__dict__; in the latter case typing # locals() at the backdoor prompt spews out lots of # useless stuff try: import __builtin__ _locals["__builtins__"] = __builtin__ except ImportError: import builtins # pylint:disable=import-error _locals["builtins"] = builtins _locals['__builtins__'] = builtins return _locals def handle(self, conn, _address): # pylint: disable=method-hidden """ Interact with one remote user. .. versionchanged:: 1.1b2 Each connection gets its own ``locals`` dictionary. Previously they were shared in a potentially unsafe manner. """ try: conn.setsockopt(socket.SOL_TCP, socket.TCP_NODELAY, True) except OSError: pass raw_file = conn.makefile(mode="r") getcurrent().stdin = _StdIn(conn, raw_file) getcurrent().stdout = _StdErr(conn, raw_file) # Swizzle the inputs getcurrent().switch_in() try: console = InteractiveConsole(self._create_interactive_locals()) # Beginning in 3.6, the console likes to print "now exiting " # but probably our socket is already closed, so this just causes problems. console.interact(banner=self.banner, exitmsg='') # pylint:disable=unexpected-keyword-arg except SystemExit: # raised by quit(); obviously this cannot propagate. pass finally: raw_file.close() conn.close() class _BaseFileLike(object): # Python 2 likes to test for this before writing to stderr. softspace = None encoding = 'utf-8' __slots__ = ( 'sock', 'fobj', 'fileno', ) def __init__(self, sock, stdin): self.sock = sock self.fobj = stdin # On Python 3, The builtin input() function (used by the # default InteractiveConsole) calls fileno() on # sys.stdin. If it's the same as the C stdin's fileno, # and isatty(fd) (C function call) returns true, # and all of that is also true for stdout, then input() will use # PyOS_Readline to get the input. # # On Python 2, the sys.stdin object has to extend the file() # class, and return true from isatty(fileno(sys.stdin.f_fp)) # (where f_fp is a C-level FILE* member) to use PyOS_Readline. # # If that doesn't hold, both versions fall back to reading and writing # using sys.stdout.write() and sys.stdin.readline(). self.fileno = sock.fileno def __getattr__(self, name): return getattr(self.fobj, name) def close(self): pass class _StdErr(_BaseFileLike): """ A file-like object that wraps the result of socket.makefile (composition instead of inheritance lets us work identically under CPython and PyPy). We write directly to the socket, avoiding the buffering that the text-oriented makefile would want to do (otherwise we'd be at the mercy of waiting on a flush() to get called for the remote user to see data); this beats putting the file in binary mode and translating everywhere with a non-default encoding. """ def flush(self): "Does nothing. raw_input() calls this, only on Python 3." def write(self, data): if not isinstance(data, bytes): data = data.encode(self.encoding) self.sock.sendall(data) class _StdIn(_BaseFileLike): # Like _StdErr, but for stdin. def readline(self, *a): try: return self.fobj.readline(*a).replace("\r\n", "\n") except UnicodeError: # Typically, under python 3, a ^C on the other end return '' if __name__ == '__main__': if not sys.argv[1:]: print('USAGE: %s PORT [banner]' % sys.argv[0]) else: BackdoorServer(('127.0.0.1', int(sys.argv[1])), banner=(sys.argv[2] if len(sys.argv) > 2 else None), locals={'hello': 'world'}).serve_forever()