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# 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
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.
_fileobj = None
saved = None
def switch(self, *args, **kw):
if self._fileobj is not None:
self.switch_in()
Greenlet.switch(self, *args, **kw)
def switch_in(self):
self.saved = sys.stdin, sys.stderr, sys.stdout
sys.stdin = sys.stdout = sys.stderr = self._fileobj
def switch_out(self):
sys.stdin, sys.stderr, sys.stdout = self.saved
self.saved = None
def throw(self, *args, **kwargs):
# pylint:disable=arguments-differ
if self.saved is None and self._fileobj 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.
"""
fobj = conn.makefile(mode="rw")
fobj = _fileobject(conn, fobj, self.stderr)
getcurrent()._fileobj = fobj
getcurrent().switch_in()
try:
console = InteractiveConsole(self._create_interactive_locals())
if sys.version_info[:3] >= (3, 6, 0):
# Beginning in 3.6, the console likes to print "now exiting <class>"
# but probably our socket is already closed, so this just causes problems.
console.interact(banner=self.banner, exitmsg='') # pylint:disable=unexpected-keyword-arg
else:
console.interact(banner=self.banner)
except SystemExit: # raised by quit()
if hasattr(sys, 'exc_clear'): # py2
sys.exc_clear()
finally:
conn.close()
fobj.close()
class _fileobject(object):
"""
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 __init__(self, sock, fobj, stderr):
self._sock = sock
self._fobj = fobj
self.stderr = stderr
def __getattr__(self, name):
return getattr(self._fobj, name)
def write(self, data):
if not isinstance(data, bytes):
data = data.encode('utf-8')
self._sock.sendall(data)
def isatty(self):
return True
def flush(self):
pass
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()
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