Source code for duplicity.backends.ssh_pexpect_backend

# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
#
# Copyright 2002 Ben Escoto <ben@emerose.org>
# Copyright 2007 Kenneth Loafman <kenneth@loafman.com>
#
# This file is part of duplicity.
#
# Duplicity is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# Duplicity is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with duplicity; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

# The following can be redefined to use different shell commands from
# ssh or scp or to add more arguments.  However, the replacements must
# have the same syntax.  Also these strings will be executed by the
# shell, so shouldn't have strange characters in them.

from future_builtins import map

import re
import string
import os

import duplicity.backend
from duplicity import globals
from duplicity import log
from duplicity.errors import BackendException


[docs]class SSHPExpectBackend(duplicity.backend.Backend): """This backend copies files using scp. List not supported. Filenames should not need any quoting or this will break.""" def __init__(self, parsed_url): """scpBackend initializer""" duplicity.backend.Backend.__init__(self, parsed_url) self.retry_delay = 10 self.scp_command = "scp" if globals.scp_command: self.scp_command = globals.scp_command self.sftp_command = "sftp" if globals.sftp_command: self.sftp_command = globals.sftp_command self.scheme = duplicity.backend.strip_prefix(parsed_url.scheme, 'pexpect') self.use_scp = (self.scheme == 'scp') # host string of form [user@]hostname if parsed_url.username: self.host_string = parsed_url.username + "@" + parsed_url.hostname else: self.host_string = parsed_url.hostname # make sure remote_dir is always valid if parsed_url.path: # remove leading '/' self.remote_dir = re.sub(r'^/', r'', parsed_url.path, 1) else: self.remote_dir = '.' self.remote_prefix = self.remote_dir + '/' # maybe use different ssh port if parsed_url.port: globals.ssh_options = globals.ssh_options + " -oPort=%s" % parsed_url.port # set some defaults if user has not specified already. if "ServerAliveInterval" not in globals.ssh_options: globals.ssh_options += " -oServerAliveInterval=%d" % ((int)(globals.timeout / 2)) if "ServerAliveCountMax" not in globals.ssh_options: globals.ssh_options += " -oServerAliveCountMax=2" # set up password self.use_getpass = globals.ssh_askpass self.password = self.get_password()
[docs] def run_scp_command(self, commandline): """ Run an scp command, responding to password prompts """ import pexpect log.Info("Running '%s'" % commandline) child = pexpect.spawn(commandline, timeout=None) if globals.ssh_askpass: state = "authorizing" else: state = "copying" while 1: if state == "authorizing": match = child.expect([pexpect.EOF, "(?i)timeout, server not responding", "(?i)pass(word|phrase .*):", "(?i)permission denied", "authenticity"]) log.Debug("State = %s, Before = '%s'" % (state, child.before.strip())) if match == 0: log.Warn("Failed to authenticate") break elif match == 1: log.Warn("Timeout waiting to authenticate") break elif match == 2: child.sendline(self.password) state = "copying" elif match == 3: log.Warn("Invalid SSH password") break elif match == 4: log.Warn("Remote host authentication failed (missing known_hosts entry?)") break elif state == "copying": match = child.expect([pexpect.EOF, "(?i)timeout, server not responding", "stalled", "authenticity", "ETA"]) log.Debug("State = %s, Before = '%s'" % (state, child.before.strip())) if match == 0: break elif match == 1: log.Warn("Timeout waiting for response") break elif match == 2: state = "stalled" elif match == 3: log.Warn("Remote host authentication failed (missing known_hosts entry?)") break elif state == "stalled": match = child.expect([pexpect.EOF, "(?i)timeout, server not responding", "ETA"]) log.Debug("State = %s, Before = '%s'" % (state, child.before.strip())) if match == 0: break elif match == 1: log.Warn("Stalled for too long, aborted copy") break elif match == 2: state = "copying" child.close(force=True) if child.exitstatus != 0: raise BackendException("Error running '%s'" % commandline)
[docs] def run_sftp_command(self, commandline, commands): """ Run an sftp command, responding to password prompts, passing commands from list """ import pexpect maxread = 2000 # expected read buffer size responses = [pexpect.EOF, "(?i)timeout, server not responding", "sftp>", "(?i)pass(word|phrase .*):", "(?i)permission denied", "authenticity", "(?i)no such file or directory", "Couldn't delete file: No such file or directory", "Couldn't delete file", "open(.*): Failure"] max_response_len = max([len(p) for p in responses[1:]]) log.Info("Running '%s'" % (commandline)) child = pexpect.spawn(commandline, timeout=None, maxread=maxread) cmdloc = 0 passprompt = 0 while 1: msg = "" match = child.expect(responses, searchwindowsize=maxread + max_response_len) log.Debug("State = sftp, Before = '%s'" % (child.before.strip())) if match == 0: break elif match == 1: msg = "Timeout waiting for response" break if match == 2: if cmdloc < len(commands): command = commands[cmdloc] log.Info("sftp command: '%s'" % (command,)) child.sendline(command) cmdloc += 1 else: command = 'quit' child.sendline(command) res = child.before elif match == 3: passprompt += 1 child.sendline(self.password) if (passprompt > 1): raise BackendException("Invalid SSH password.") elif match == 4: if not child.before.strip().startswith("mkdir"): msg = "Permission denied" break elif match == 5: msg = "Host key authenticity could not be verified (missing known_hosts entry?)" break elif match == 6: if not child.before.strip().startswith("rm"): msg = "Remote file or directory does not exist in command='%s'" % (commandline,) break elif match == 7: if not child.before.strip().startswith("Removing"): msg = "Could not delete file in command='%s'" % (commandline,) break elif match == 8: msg = "Could not delete file in command='%s'" % (commandline,) break elif match == 9: msg = "Could not open file in command='%s'" % (commandline,) break child.close(force=True) if child.exitstatus == 0: return res else: raise BackendException("Error running '%s': %s" % (commandline, msg))
def _put(self, source_path, remote_filename): if self.use_scp: self.put_scp(source_path, remote_filename) else: self.put_sftp(source_path, remote_filename)
[docs] def put_sftp(self, source_path, remote_filename): commands = ["put \"%s\" \"%s.%s.part\"" % (source_path.name, self.remote_prefix, remote_filename), "rename \"%s.%s.part\" \"%s%s\"" % (self.remote_prefix, remote_filename, self.remote_prefix, remote_filename)] commandline = ("%s %s %s" % (self.sftp_command, globals.ssh_options, self.host_string)) self.run_sftp_command(commandline, commands)
[docs] def put_scp(self, source_path, remote_filename): commandline = "%s %s %s %s:%s%s" % \ (self.scp_command, globals.ssh_options, source_path.name, self.host_string, self.remote_prefix, remote_filename) self.run_scp_command(commandline)
def _get(self, remote_filename, local_path): if self.use_scp: self.get_scp(remote_filename, local_path) else: self.get_sftp(remote_filename, local_path)
[docs] def get_sftp(self, remote_filename, local_path): commands = ["get \"%s%s\" \"%s\"" % (self.remote_prefix, remote_filename, local_path.name)] commandline = ("%s %s %s" % (self.sftp_command, globals.ssh_options, self.host_string)) self.run_sftp_command(commandline, commands)
[docs] def get_scp(self, remote_filename, local_path): commandline = "%s %s %s:%s%s %s" % \ (self.scp_command, globals.ssh_options, self.host_string, self.remote_prefix, remote_filename, local_path.name) self.run_scp_command(commandline)
def _list(self): # Note that this command can get confused when dealing with # files with newlines in them, as the embedded newlines cannot # be distinguished from the file boundaries. dirs = self.remote_dir.split(os.sep) if len(dirs) > 0: if not dirs[0]: dirs = dirs[1:] dirs[0] = '/' + dirs[0] mkdir_commands = [] for d in dirs: mkdir_commands += ["mkdir \"%s\"" % (d)] + ["cd \"%s\"" % (d)] commands = mkdir_commands + ["ls -1"] commandline = ("%s %s %s" % (self.sftp_command, globals.ssh_options, self.host_string)) l = self.run_sftp_command(commandline, commands).split('\n')[1:] return [x for x in map(string.strip, l) if x] def _delete(self, filename): commands = ["cd \"%s\"" % (self.remote_dir,)] commands.append("rm \"%s\"" % filename) commandline = ("%s %s %s" % (self.sftp_command, globals.ssh_options, self.host_string)) self.run_sftp_command(commandline, commands)
duplicity.backend.register_backend("pexpect+sftp", SSHPExpectBackend) duplicity.backend.register_backend("pexpect+scp", SSHPExpectBackend) duplicity.backend.uses_netloc.extend(['pexpect+sftp', 'pexpect+scp'])