shell bypass 403
# -*- test-case-name: twisted.conch.test.test_recvline -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Basic line editing support.
@author: Jp Calderone
"""
import string
from zope.interface import implementer
from twisted.conch.insults import insults, helper
from twisted.python import log, reflect
from twisted.python.compat import iterbytes
_counters = {}
class Logging(object):
"""
Wrapper which logs attribute lookups.
This was useful in debugging something, I guess. I forget what.
It can probably be deleted or moved somewhere more appropriate.
Nothing special going on here, really.
"""
def __init__(self, original):
self.original = original
key = reflect.qual(original.__class__)
count = _counters.get(key, 0)
_counters[key] = count + 1
self._logFile = open(key + '-' + str(count), 'w')
def __str__(self):
return str(super(Logging, self).__getattribute__('original'))
def __repr__(self):
return repr(super(Logging, self).__getattribute__('original'))
def __getattribute__(self, name):
original = super(Logging, self).__getattribute__('original')
logFile = super(Logging, self).__getattribute__('_logFile')
logFile.write(name + '\n')
return getattr(original, name)
@implementer(insults.ITerminalTransport)
class TransportSequence(object):
"""
An L{ITerminalTransport} implementation which forwards calls to
one or more other L{ITerminalTransport}s.
This is a cheap way for servers to keep track of the state they
expect the client to see, since all terminal manipulations can be
send to the real client and to a terminal emulator that lives in
the server process.
"""
for keyID in (b'UP_ARROW', b'DOWN_ARROW', b'RIGHT_ARROW', b'LEFT_ARROW',
b'HOME', b'INSERT', b'DELETE', b'END', b'PGUP', b'PGDN',
b'F1', b'F2', b'F3', b'F4', b'F5', b'F6', b'F7', b'F8',
b'F9', b'F10', b'F11', b'F12'):
execBytes = keyID + b" = object()"
execStr = execBytes.decode("ascii")
exec(execStr)
TAB = b'\t'
BACKSPACE = b'\x7f'
def __init__(self, *transports):
assert transports, (
"Cannot construct a TransportSequence with no transports")
self.transports = transports
for method in insults.ITerminalTransport:
exec("""\
def %s(self, *a, **kw):
for tpt in self.transports:
result = tpt.%s(*a, **kw)
return result
""" % (method, method))
class LocalTerminalBufferMixin(object):
"""
A mixin for RecvLine subclasses which records the state of the terminal.
This is accomplished by performing all L{ITerminalTransport} operations on both
the transport passed to makeConnection and an instance of helper.TerminalBuffer.
@ivar terminalCopy: A L{helper.TerminalBuffer} instance which efforts
will be made to keep up to date with the actual terminal
associated with this protocol instance.
"""
def makeConnection(self, transport):
self.terminalCopy = helper.TerminalBuffer()
self.terminalCopy.connectionMade()
return super(LocalTerminalBufferMixin, self).makeConnection(
TransportSequence(transport, self.terminalCopy))
def __str__(self):
return str(self.terminalCopy)
class RecvLine(insults.TerminalProtocol):
"""
L{TerminalProtocol} which adds line editing features.
Clients will be prompted for lines of input with all the usual
features: character echoing, left and right arrow support for
moving the cursor to different areas of the line buffer, backspace
and delete for removing characters, and insert for toggling
between typeover and insert mode. Tabs will be expanded to enough
spaces to move the cursor to the next tabstop (every four
characters by default). Enter causes the line buffer to be
cleared and the line to be passed to the lineReceived() method
which, by default, does nothing. Subclasses are responsible for
redrawing the input prompt (this will probably change).
"""
width = 80
height = 24
TABSTOP = 4
ps = (b'>>> ', b'... ')
pn = 0
_printableChars = string.printable.encode("ascii")
def connectionMade(self):
# A list containing the characters making up the current line
self.lineBuffer = []
# A zero-based (wtf else?) index into self.lineBuffer.
# Indicates the current cursor position.
self.lineBufferIndex = 0
t = self.terminal
# A map of keyIDs to bound instance methods.
self.keyHandlers = {
t.LEFT_ARROW: self.handle_LEFT,
t.RIGHT_ARROW: self.handle_RIGHT,
t.TAB: self.handle_TAB,
# Both of these should not be necessary, but figuring out
# which is necessary is a huge hassle.
b'\r': self.handle_RETURN,
b'\n': self.handle_RETURN,
t.BACKSPACE: self.handle_BACKSPACE,
t.DELETE: self.handle_DELETE,
t.INSERT: self.handle_INSERT,
t.HOME: self.handle_HOME,
t.END: self.handle_END}
self.initializeScreen()
def initializeScreen(self):
# Hmm, state sucks. Oh well.
# For now we will just take over the whole terminal.
self.terminal.reset()
self.terminal.write(self.ps[self.pn])
# XXX Note: I would prefer to default to starting in insert
# mode, however this does not seem to actually work! I do not
# know why. This is probably of interest to implementors
# subclassing RecvLine.
# XXX XXX Note: But the unit tests all expect the initial mode
# to be insert right now. Fuck, there needs to be a way to
# query the current mode or something.
# self.setTypeoverMode()
self.setInsertMode()
def currentLineBuffer(self):
s = b''.join(self.lineBuffer)
return s[:self.lineBufferIndex], s[self.lineBufferIndex:]
def setInsertMode(self):
self.mode = 'insert'
self.terminal.setModes([insults.modes.IRM])
def setTypeoverMode(self):
self.mode = 'typeover'
self.terminal.resetModes([insults.modes.IRM])
def drawInputLine(self):
"""
Write a line containing the current input prompt and the current line
buffer at the current cursor position.
"""
self.terminal.write(self.ps[self.pn] + b''.join(self.lineBuffer))
def terminalSize(self, width, height):
# XXX - Clear the previous input line, redraw it at the new
# cursor position
self.terminal.eraseDisplay()
self.terminal.cursorHome()
self.width = width
self.height = height
self.drawInputLine()
def unhandledControlSequence(self, seq):
pass
def keystrokeReceived(self, keyID, modifier):
m = self.keyHandlers.get(keyID)
if m is not None:
m()
elif keyID in self._printableChars:
self.characterReceived(keyID, False)
else:
log.msg("Received unhandled keyID: %r" % (keyID,))
def characterReceived(self, ch, moreCharactersComing):
if self.mode == 'insert':
self.lineBuffer.insert(self.lineBufferIndex, ch)
else:
self.lineBuffer[self.lineBufferIndex:self.lineBufferIndex+1] = [ch]
self.lineBufferIndex += 1
self.terminal.write(ch)
def handle_TAB(self):
n = self.TABSTOP - (len(self.lineBuffer) % self.TABSTOP)
self.terminal.cursorForward(n)
self.lineBufferIndex += n
self.lineBuffer.extend(iterbytes(b' ' * n))
def handle_LEFT(self):
if self.lineBufferIndex > 0:
self.lineBufferIndex -= 1
self.terminal.cursorBackward()
def handle_RIGHT(self):
if self.lineBufferIndex < len(self.lineBuffer):
self.lineBufferIndex += 1
self.terminal.cursorForward()
def handle_HOME(self):
if self.lineBufferIndex:
self.terminal.cursorBackward(self.lineBufferIndex)
self.lineBufferIndex = 0
def handle_END(self):
offset = len(self.lineBuffer) - self.lineBufferIndex
if offset:
self.terminal.cursorForward(offset)
self.lineBufferIndex = len(self.lineBuffer)
def handle_BACKSPACE(self):
if self.lineBufferIndex > 0:
self.lineBufferIndex -= 1
del self.lineBuffer[self.lineBufferIndex]
self.terminal.cursorBackward()
self.terminal.deleteCharacter()
def handle_DELETE(self):
if self.lineBufferIndex < len(self.lineBuffer):
del self.lineBuffer[self.lineBufferIndex]
self.terminal.deleteCharacter()
def handle_RETURN(self):
line = b''.join(self.lineBuffer)
self.lineBuffer = []
self.lineBufferIndex = 0
self.terminal.nextLine()
self.lineReceived(line)
def handle_INSERT(self):
assert self.mode in ('typeover', 'insert')
if self.mode == 'typeover':
self.setInsertMode()
else:
self.setTypeoverMode()
def lineReceived(self, line):
pass
class HistoricRecvLine(RecvLine):
"""
L{TerminalProtocol} which adds both basic line-editing features and input history.
Everything supported by L{RecvLine} is also supported by this class. In addition, the
up and down arrows traverse the input history. Each received line is automatically
added to the end of the input history.
"""
def connectionMade(self):
RecvLine.connectionMade(self)
self.historyLines = []
self.historyPosition = 0
t = self.terminal
self.keyHandlers.update({t.UP_ARROW: self.handle_UP,
t.DOWN_ARROW: self.handle_DOWN})
def currentHistoryBuffer(self):
b = tuple(self.historyLines)
return b[:self.historyPosition], b[self.historyPosition:]
def _deliverBuffer(self, buf):
if buf:
for ch in iterbytes(buf[:-1]):
self.characterReceived(ch, True)
self.characterReceived(buf[-1:], False)
def handle_UP(self):
if self.lineBuffer and self.historyPosition == len(self.historyLines):
self.historyLines.append(b''.join(self.lineBuffer))
if self.historyPosition > 0:
self.handle_HOME()
self.terminal.eraseToLineEnd()
self.historyPosition -= 1
self.lineBuffer = []
self._deliverBuffer(self.historyLines[self.historyPosition])
def handle_DOWN(self):
if self.historyPosition < len(self.historyLines) - 1:
self.handle_HOME()
self.terminal.eraseToLineEnd()
self.historyPosition += 1
self.lineBuffer = []
self._deliverBuffer(self.historyLines[self.historyPosition])
else:
self.handle_HOME()
self.terminal.eraseToLineEnd()
self.historyPosition = len(self.historyLines)
self.lineBuffer = []
self.lineBufferIndex = 0
def handle_RETURN(self):
if self.lineBuffer:
self.historyLines.append(b''.join(self.lineBuffer))
self.historyPosition = len(self.historyLines)
return RecvLine.handle_RETURN(self)