def run_async (self, command) :
        """
        Run a shell command, but don't wait for prompt -- just return.  It is up
        to caller to eventually search for the prompt again (see
        :func:`find_prompt`.  Meanwhile, the caller can interact with the called
        command, via the I/O channels.

        :type  command: string
        :param command: shell command to run.  

        For async execution, we don't care if the command is doing i/o redirection or not.
        """

        with self.pty_shell.rlock :

            # we expect the shell to be in 'ground state' when running an asyncronous
            # command -- thus we can check if the shell is alive before doing so,
            # and restart if needed
            if not self.pty_shell.alive (recover=True) :
                raise se.IncorrectState ("Cannot run command:\n%s" \
                                      % self.pty_shell.autopsy ())

            try :
                command = command.strip ()
                self.send ("%s\n" % command)

            except Exception as e :
                raise ptye.translate_exception (e)

    def read_from_remote (self, src) :
        """
        :type  src: string
        :param src: path to source file to staged from
                    The src path is not an URL, but expected to be a path
                    relative to the shell's URL.
        """

        try :
            # FIXME: make this relative to the shell's pwd?  Needs pwd in
            # prompt, and updating pwd state on every find_prompt.

            # first, write data into a tmp file
            fname   = self.base + "/staging.%s" % id(self)

            _ = self.factory.run_copy_from (self.pty_info, src, fname)

            fhandle = open (fname, 'r')
            out = fhandle.read  ()
            fhandle.close  ()

            os.remove (fname)

            return out

        except Exception as e :
            raise ptye.translate_exception (e)

    def find_prompt (self) :
        """
        If run_async was called, a command is running on the shell.  find_prompt
        can be used to collect its output up to the point where the shell prompt
        re-appears (i.e. when the command finishes).


        Note that this method blocks until the command finishes.  Future
        versions of this call may add a timeout parameter.
        """

        with self.pty_shell.rlock :

            try :

                match = None
                fret  = None

                while fret == None :
                    fret, match = self.pty_shell.find ([self.prompt], _PTY_TIMEOUT)
                
              # self.logger.debug  ("find prompt '%s' in '%s'" % (self.prompt, match))
                ret, txt = self._eval_prompt (match)

                return (ret, txt)

            except Exception as e :
                raise ptye.translate_exception (e)

    def read_from_remote (self, src) :
        """
        :type  src: string
        :param src: path to source file to staged from
                    The src path is not an URL, but expected to be a path
                    relative to the shell's URL.
        """

        try :

          # self._trace ("read      : %s" % src)

            # FIXME: make this relative to the shell's pwd?  Needs pwd in
            # prompt, and updating pwd state on every find_prompt.

            # first, write data into a tmp file
            fhandle, fname = tempfile.mkstemp(suffix='.tmp', prefix='rs_pty_staging_')
            _ = self.stage_from_remote (src, fname)
            os.close(fhandle)

            os.system('sync') # WTF?  Why do I need this?

            fhandle2 = open(fname, 'r')
            out      = fhandle2.read()
            fhandle2.close()

            os.remove(fname)

            return out

        except Exception as e :
            raise ptye.translate_exception (e)

    def _eval_prompt (self, data, new_prompt=None) :
        """
        This method will match the given data against the current prompt regex,
        and expects to find an integer as match -- which is then returned, along
        with all leading data, in a tuple
        """

        with self.pty_shell.rlock :

            try :

                prompt    = self.prompt
                prompt_re = self.prompt_re

                if  new_prompt :
                    prompt    = new_prompt
                    prompt_re = re.compile ("^(.*)%s\s*$" % prompt, re.DOTALL)


                result = None
                if  not data :
                    raise se.NoSuccess ("cannot not parse prompt (%s), invalid data (%s)" \
                                     % (prompt, data))

                result = prompt_re.match (data)

                if  not result :
                    self.logger.debug  ("could not parse prompt (%s) (%s)" % (prompt, data))
                    raise se.NoSuccess ("could not parse prompt (%s) (%s)" % (prompt, data))

                txt = result.group (1)
                ret = 0

                if  len (result.groups ()) != 2 :
                    if  new_prompt :
                        self.logger.warn   ("prompt does not capture exit value (%s)" % prompt)
                      # raise se.NoSuccess ("prompt does not capture exit value (%s)" % prompt)

                else :
                    try :
                        ret = int(result.group (2))
                    except ValueError :
                        # apparently, this is not an integer. Print a warning, and
                        # assume success -- the calling entity needs to evaluate the
                        # remainder...
                        ret = 0
                        self.logger.warn  ("prompt not suitable for error checks (%s)" % prompt)
                        txt += "\n%s" % result.group (2)

                # if that worked, we can permanently set new_prompt
                if  new_prompt :
                    self.set_prompt (new_prompt)

                return (ret, txt)

            except Exception as e :
                
                raise ptye.translate_exception (e, "Could not eval prompt")

    def write (self, data, nolog=False) :
        """
        This method will repeatedly attempt to push the given data into the
        child's stdin pipe, until it succeeds to write all data.
        """

        with self.rlock :

            if not self.alive (recover=False) :
                raise ptye.translate_exception (se.NoSuccess ("cannot write to dead process (%s) [%5d]" \
                                                % (self.cache[-256:], self.parent_in)))

            try :

                log = self._hide_data (data, nolog)
                log =  log.replace ('\n', '\\n')
                log =  log.replace ('\r', '')
                if  len(log) > _DEBUG_MAX :
                    self.logger.debug ("write: [%5d] [%5d] (%s ... %s)" \
                                    % (self.parent_in, len(data), log[:30], log[-30:]))
                else :
                    self.logger.debug ("write: [%5d] [%5d] (%s)" \
                                    % (self.parent_in, len(data), log))

                # attempt to write forever -- until we succeeed
                while data :

                    # check if the pty pipe is ready for data
                    _, wlist, _ = select.select ([], [self.parent_in], [], _POLLDELAY)

                    for f in wlist :
                        
                        # write will report the number of written bytes
                        size = os.write (f, data)

                        # otherwise, truncate by written data, and try again
                        data = data[size:]

                        if data :
                            self.logger.info ("write: [%5d] [%5d]" % (f, size))


            except Exception as e :
                raise ptye.translate_exception (e, "write to process failed (%s)" % e)

    def find (self, patterns, timeout=-1) :
        """
        Note that this method blocks until pattern is found in the shell I/O.
        """

        with self.pty_shell.rlock :

            try :
                return self.pty_shell.find (patterns, timeout=timeout)

            except Exception as e :
                raise ptye.translate_exception (e)

    def __init__ (self, command, logger=None) :
        """
        The class constructor, which runs (execvpe) command in a separately
        forked process.  The bew process will inherit the environment of the
        application process.

        :type  command: string or list of strings
        :param command: The given command is what is run as a child, and
        fed/drained via pty pipes.  If given as string, command is split into an
        array of strings, using :func:`shlex.split`.

        :type  logger:  :class:`radical.utils.logger.Logger` instance
        :param logger:  logger stream to send status messages to.
        """

        self._debug = False

        self.logger = logger
        if  not  self.logger : self.logger = rul.getLogger ('saga', 'PTYProcess') 
        self.logger.debug ("PTYProcess init %s" % self)


        if isinstance (command, basestring) :
            command = shlex.split (command)

        if not isinstance (command, list) :
            raise se.BadParameter ("PTYProcess expects string or list command")

        if len(command) < 1 :
            raise se.BadParameter ("PTYProcess expects non-empty command")

        self.rlock   = ru.RLock ("pty process %s" % command)

        self.command = command # list of strings too run()


        self.cache   = ""      # data cache
        self.tail    = ""      # tail of data data cache for error messages
        self.child   = None    # the process as created by subprocess.Popen
        self.ptyio   = None    # the process' io channel, from pty.fork()

        self.exit_code        = None  # child died with code (may be revived)
        self.exit_signal      = None  # child kill by signal (may be revived)

        self.recover_max      = 3  # TODO: make configure option.  This does not
        self.recover_attempts = 0  # apply for recovers triggered by gc_timeout!


        try :
            self.initialize ()

        except Exception as e :
            raise ptye.translate_exception (e, "pty or process creation failed")

    def alive (self, recover=False) :
        """
        The shell is assumed to be alive if the shell processes lives.
        Attempt to restart shell if recover==True
        """

        with self.pty_shell.rlock :

            try :
                return self.pty_shell.alive (recover)

            except Exception as e :
                raise ptye.translate_exception (e)

    def send (self, data) :
        """
        send data to the shell.  No newline is appended!
        """

        with self.pty_shell.rlock :

            if not self.pty_shell.alive (recover=False) :
                raise se.IncorrectState ("Cannot send data:\n%s" \
                                      % self.pty_shell.autopsy ())

            try :
                self.pty_shell.write ("%s" % data)

            except Exception as e :
                raise ptye.translate_exception (e)

    def _eval_prompt (self, data, new_prompt=None) :
        """
        This method will match the given data against the current prompt regex,
        and expects to find an integer as match -- which is then returned, along
        with all leading data, in a tuple
        """

        with self.pty_shell.rlock :

            try :

                prompt    = self.prompt
                prompt_re = self.prompt_re

                if  new_prompt :
                    prompt    = new_prompt
                    prompt_re = re.compile ("^(.*)%s\s*$" % prompt, re.DOTALL)


                result = None
                if  not data :
                    raise se.NoSuccess ("cannot not parse prompt (%s), invalid data (%s)" \
                                     % (prompt, data))

                result = prompt_re.match (data)

                if  not result :
                    self.logger.debug  ("could not parse prompt (%s) (%s)" % (prompt, data))
                    raise se.NoSuccess ("could not parse prompt (%s) (%s)" % (prompt, data))

                if  len (result.groups ()) != 2 :
                    self.logger.debug  ("prompt does not capture exit value (%s)" % prompt)
                    raise se.NoSuccess ("prompt does not capture exit value (%s)" % prompt)

                txt =     result.group (1)
                ret = int(result.group (2)) 

                # if that worked, we can permanently set new_prompt
                if  new_prompt :
                    self.set_prompt (new_prompt)

                return (ret, txt)

            except Exception as e :
                
                raise ptye.translate_exception (e, "Could not eval prompt")

    def stage_from_remote (self, src, tgt, cp_flags="") :
        """
        :type  src: string
        :param tgt: path to source file to stage from.
                    The tgt path is not an URL, but expected to be a path
                    relative to the shell's URL.

        :type  tgt: string
        :param src: path of local target file to stage to.
                    The tgt path is not an URL, but expected to be a path
                    relative to the current working directory.
        """

        # FIXME: make this relative to the shell's pwd?  Needs pwd in
        # prompt, and updating pwd state on every find_prompt.

        try :
            return self.factory.run_copy_from (self.pty_info, src, tgt, cp_flags)

        except Exception as e :
            raise ptye.translate_exception (e)

    def write_to_remote (self, src, tgt) :
        """
        :type  src: string
        :param src: data to be staged into the target file

        :type  tgt: string
        :param tgt: path to target file to staged to
                    The tgt path is not an URL, but expected to be a path
                    relative to the shell's URL.

        The content of the given string is pasted into a file (specified by tgt)
        on the remote system.  If that file exists, it is overwritten.
        A NoSuccess exception is raised if writing the file was not possible
        (missing permissions, incorrect path, etc.).
        """

        try :

          # self._trace ("write     : %s -> %s" % (src, tgt))

            # FIXME: make this relative to the shell's pwd?  Needs pwd in
            # prompt, and updating pwd state on every find_prompt.

            # first, write data into a tmp file
            fname   = self.base + "/staging.%s" % id(self)
            fhandle = open (fname, 'wb')
            fhandle.write  (src)
            fhandle.flush  ()
            fhandle.close  ()

            ret = self.stage_to_remote (fname, tgt)

            os.remove (fname)

            return ret

        except Exception as e :
            raise ptye.translate_exception (e)

#.........这里部分代码省略.........
        this method is effectively matching lines -- but note that '$' will also
        match the end of the (currently available) data stream.

        The call actually returns a tuple, containing the index of the matching
        pattern, and the string up to the match as described above.

        If no pattern is found before timeout, the call returns (None, None).
        Negative timeouts will block until a match is found

        Note that the pattern are interpreted with the re.M (multi-line) and
        re.S (dot matches all) regex flags.

        Performance: the call is doing repeated string regex searches over
        whatever data it finds.  On complex regexes, and large data, and small
        read buffers, this method can be expensive.  

        Note: the returned data get '\\\\r' stripped.

        Note: ansi-escape sequences are also stripped before matching, but are
        kept in the returned data.
        """

        def escape (txt) :
            pat = re.compile(r'\x1b[^m]*m')
            return pat.sub ('', txt)

        _debug = False

        with self.rlock :

            try :
                start = time.time ()                       # startup timestamp
                ret   = []                                 # array of read lines
                patts = []                                 # compiled patterns
                data  = self.cache                         # initial data to check
                self.cache = ""

                if  not data : # empty cache?
                    data = self.read (timeout=_POLLDELAY)

                # pre-compile the given pattern, to speed up matching
                for pattern in patterns :
                    patts.append (re.compile (pattern, re.MULTILINE | re.DOTALL))

                # we wait forever -- there are two ways out though: data matches
                # a pattern, or timeout passes
                while True :

                    # skip non-lines
                    if  not data :
                        data += self.read (timeout=_POLLDELAY)

                    if  _debug : print ">>%s<<" % data

                    escaped = escape (data)
                    if _debug : print 'data    ==%s==' % data
                    if _debug : print 'escaped ==%s==' % escaped

                    # check current data for any matching pattern
                    for n in range (0, len(patts)) :

                        escaped = data
                      # escaped = escape (data)
                      # print '-- 1 --%s--' % data
                      # print '-- 2 --%s--' % escaped

                        match = patts[n].search (escaped)
                        if _debug : print "==%s==" % patterns[n]
                        if _debug : print match

                        if match :
                            # a pattern matched the current data: return a tuple of
                            # pattern index and matching data.  The remainder of the
                            # data is cached.
                            ret  = escaped[0:match.end()]
                            self.cache = escaped[match.end():] 

                            if _debug : print "~~match!~~ %s" % escaped[match.start():match.end()]
                            if _debug : print "~~match!~~ %s" % (len(escaped))
                            if _debug : print "~~match!~~ %s" % (str(match.span()))
                            if _debug : print "~~match!~~ %s" % (ret)

                            return (n, ret.replace('\r', ''))

                    # if a timeout is given, and actually passed, return
                    # a non-match and a copy of the data we looked at
                    if timeout == 0 :
                        return (None, str(escaped))

                    if timeout > 0 :
                        now = time.time ()
                        if (now-start) > timeout :
                            self.cache = escaped
                            return (None, str(escaped))

                    # no match yet, still time -- read more data
                    data += self.read (timeout=_POLLDELAY)

            except se.NoSuccess as e :
                raise ptye.translate_exception (e, "(%s)" % data)

    def run_copy_from (self, src, tgt, cp_flags="") :
        """ 
        This initiates a slave copy connection.   Src is interpreted as path on
        the remote host, tgt as local path.

        We have to do the same mkdir trick as for the run_copy_to, but here we
        need to expand wildcards on the *remote* side :/
        """

        self._trace ("copy  from: %s -> %s" % (src, tgt))

        with self.pty_shell.rlock :

            info = self.pty_info
            repl = dict ({'src'      : src, 
                          'tgt'      : tgt, 
                          'cp_flags' : cp_flags}.items ()+ info.items ())

            # at this point, we do have a valid, living master
            s_cmd = info['scripts'][info['copy_type']]['copy_from']    % repl
            s_in  = info['scripts'][info['copy_type']]['copy_from_in'] % repl

            if  not s_in :
                # this code path does not use an interactive shell for copy --
                # so the above s_cmd is all we want to run, really.  We get
                # do not use the chached cp_slave in this case, but just run the
                # command.  We do not have a list of transferred files though,
                # yet -- that should be parsed from the proc output.
                cp_proc = supp.PTYProcess (s_cmd)
                cp_proc.wait ()
                if  cp_proc.exit_code :
                    raise ptye.translate_exception (se.NoSuccess ("file copy failed: %s" % out))

                return list()

            if  not self.cp_slave :
                self._trace ("get cp slave")
                self.cp_slave = self.factory.get_cp_slave (s_cmd, info)

            prep = ""

            if  'sftp' in s_cmd :
                # prepare target dirs for recursive copy, if needed
                self.cp_slave.write (" ls %s\n" % src)
                _, out = self.cp_slave.find (["^sftp> "], -1)

                src_list = out[1].split ('/n')

                for s in src_list :
                    if  os.path.isdir (s) :
                        prep += "lmkdir %s/%s\n" % (tgt, os.path.basename (s))


            _      = self.cp_slave.write    ("%s%s\n" % (prep, s_in))
            _, out = self.cp_slave.find     (['[\$\>\]] *$'], -1)

            # FIXME: we don't really get exit codes from copy
          # if  self.cp_slave.exit_code != 0 :
          #     raise se.NoSuccess._log (info['logger'], "file copy failed: %s" % out)

            if 'Invalid flag' in out :
                raise se.NoSuccess._log (info['logger'], "sftp version not supported (%s)" % out)

            if 'No such file or directory' in out :
                raise se.DoesNotExist._log (info['logger'], "file copy failed: %s" % out)

            if 'is not a directory' in out :
                raise se.BadParameter._log (info['logger'], "file copy failed: %s" % out)

            if  'sftp' in s_cmd :
                if 'not found' in out :
                    raise se.BadParameter._log (info['logger'], "file copy failed: %s" % out)


            # we run copy with -v, so get a list of files which have been copied
            # -- we parse that list and return it.  we interpret the *second*
            # word on the line as name of src file.
            lines = out.split ('\n')
            files = []

            for line in lines :

                elems = line.split (' ', 3)
                
                if  elems and len(elems) > 1 and elems[0] == 'Fetching' :

                    f = elems[1]

                    # remove quotes
                    if  f :

                        if  f[ 0] in ["'", '"', '`']  :  f = f[1:  ]
                        if  f[-1] in ["'", '"', '`']  :  f = f[ :-1]

                    # ignore empty lines
                    if  f :
                        files.append (f)

            info['logger'].debug ("copy done: %s" % files)

#.........这里部分代码省略.........

#.........这里部分代码省略.........
        """

        with self.pty_shell.rlock :

            # we expect the shell to be in 'ground state' when running a syncronous
            # command -- thus we can check if the shell is alive before doing so,
            # and restart if needed
            if not self.pty_shell.alive (recover=True) :
                raise se.IncorrectState ("Can't run command -- shell died:\n%s" \
                                      % self.pty_shell.autopsy ())

            try :

                command = command.strip ()
                if command.endswith ('&') :
                    raise se.BadParameter ("run_sync can only run foreground jobs ('%s')" \
                                        % command)

                redir = ""
                _err  = "/tmp/saga-python.ssh-job.stderr.$$"

                if  iomode == IGNORE :
                    redir  =  " 1>>/dev/null 2>>/dev/null"

                if  iomode == MERGED :
                    redir  =  " 2>&1"

                if  iomode == SEPARATE :
                    redir  =  " 2>%s" % _err

                if  iomode == STDOUT :
                    redir  =  " 2>/dev/null"

                if  iomode == STDERR :
                    redir  =  " 2>&1 1>/dev/null"

                if  iomode == None :
                    redir  =  ""

                self.logger.debug    ('run_sync: %s%s'   % (command, redir))
                self.pty_shell.write (          "%s%s\n" % (command, redir))


                # If given, switch to new prompt pattern right now...
                prompt = self.prompt
                if  new_prompt :
                    prompt = new_prompt

                # command has been started - now find prompt again.  
                fret, match = self.pty_shell.find ([prompt], timeout=-1.0)  # blocks

                if  fret == None :
                    # not find prompt after blocking?  BAD!  Restart the shell
                    self.finalize (kill_pty=True)
                    raise se.IncorrectState ("run_sync failed, no prompt (%s)" % command)


                ret, txt = self._eval_prompt (match, new_prompt)

                stdout = None
                stderr = None

                if  iomode == IGNORE :
                    pass

                if  iomode == MERGED :
                    stdout =  txt

                if  iomode == SEPARATE :
                    stdout =  txt

                    self.pty_shell.write (" cat %s\n" % _err)
                    fret, match = self.pty_shell.find ([self.prompt], timeout=-1.0)  # blocks

                    if  fret == None :
                        # not find prompt after blocking?  BAD!  Restart the shell
                        self.finalize (kill_pty=True)
                        raise se.IncorrectState ("run_sync failed, no prompt (%s)" \
                                              % command)

                    _ret, _stderr = self._eval_prompt (match)
                    if  _ret :
                        raise se.IncorrectState ("run_sync failed, no stderr (%s: %s)" \
                                              % (_ret, _stderr))
                    stderr =  _stderr


                if  iomode == STDOUT :
                    stdout =  txt

                if  iomode == STDERR :
                    stderr =  txt

                if  iomode == None :
                    stdout =  txt

                return (ret, stdout, stderr)

            except Exception as e :
                raise ptye.translate_exception (e)

    def run_copy_to (self, src, tgt, cp_flags="") :
        """ 
        This initiates a slave copy connection.   Src is interpreted as local
        path, tgt as path on the remote host.

        Now, this is ugly when over sftp: sftp supports recursive copy, and
        wildcards, all right -- but for recursive copies, it wants the target
        dir to exist -- so, we have to check if the local src is a  dir, and if
        so, we first create the target before the copy.  Worse, for wildcards we
        have to do a local expansion, and the to do the same for each entry...
        """

        self._trace ("copy  to  : %s -> %s" % (src, tgt))

        with self.pty_shell.rlock :

            info = self.pty_info
            repl = dict ({'src'      : src, 
                          'tgt'      : tgt, 
                          'cp_flags' : cp_flags}.items () + info.items ())

            # at this point, we do have a valid, living master
            s_cmd = info['scripts'][info['copy_type']]['copy_to']    % repl
            s_in  = info['scripts'][info['copy_type']]['copy_to_in'] % repl

            if  not s_in :
                # this code path does not use an interactive shell for copy --
                # so the above s_cmd is all we want to run, really.  We get
                # do not use the chached cp_slave in this case, but just run the
                # command.  We do not have a list of transferred files though,
                # yet -- that should be parsed from the proc output.

                cp_proc = supp.PTYProcess (s_cmd)
                out = cp_proc.wait ()
                if  cp_proc.exit_code :
                    raise ptye.translate_exception (se.NoSuccess ("file copy failed: %s" % out))

                return list()


            # this code path uses an interactive shell to transfer files, of
            # some form, such as sftp.  Get the shell cp_slave from cache, and
            # run the actual copy command.
            if  not self.cp_slave :
                self._trace ("get cp slave")
                self.cp_slave = self.factory.get_cp_slave (s_cmd, info)

            prep = ""
            if  'sftp' in s_cmd :
                # prepare target dirs for recursive copy, if needed
                import glob
                src_list = glob.glob (src)
                for s in src_list :
                    if  os.path.isdir (s) :
                        prep += "mkdir %s/%s\n" % (tgt, os.path.basename (s))


            _      = self.cp_slave.write    ("%s%s\n" % (prep, s_in))
            _, out = self.cp_slave.find     (['[\$\>\]]\s*$'], -1)
            _, out = self.cp_slave.find     (['[\$\>\]]\s*$'], 1.0)

            # FIXME: we don't really get exit codes from copy
            # if  self.cp_slave.exit_code != 0 :
            #     raise se.NoSuccess._log (info['logger'], "file copy failed: %s" % str(out))

            if 'Invalid flag' in out :
                raise se.NoSuccess._log (info['logger'], "sftp version not supported (%s)" % str(out))

            if 'No such file or directory' in out :
                raise se.DoesNotExist._log (info['logger'], "file copy failed: %s" % str(out))

            if 'is not a directory' in out :
                raise se.BadParameter._log (info['logger'], "File copy failed: %s" % str(out))

            if  'sftp' in s_cmd :
                if 'not found' in out :
                    raise se.BadParameter._log (info['logger'], "file copy failed: %s" % out)


            # we interpret the first word on the line as name of src file -- we
            # will return a list of those
            lines = out.split ('\n')
            files = []

            for line in lines :

                elems = line.split (' ', 2)

                if  elems :

                    f = elems[0]

                    # remove quotes
                    if  f :

                        if  f[ 0] in ["'", '"', '`'] : f = f[1:  ]
                        if  f[-1] in ["'", '"', '`'] : f = f[ :-1]

                    # ignore empty lines
                    if  f :
#.........这里部分代码省略.........

#.........这里部分代码省略.........

                        # FIXME:  consider better timeout
                        n, match = pty_shell.find(prompt_patterns, delay)

                    # --------------------------------------------------------------
                    elif n == 0:
                        logger.info("got password prompt")
                        if not shell_pass:
                            raise se.AuthenticationFailed("prompted for unknown password (%s)" % match)

                        pty_shell.write("%s\n" % shell_pass, nolog=True)
                        n, match = pty_shell.find(prompt_patterns, delay)

                    # --------------------------------------------------------------
                    elif n == 1:
                        logger.info("got passphrase prompt : %s" % match)

                        start = string.find(match, "'", 0)
                        end = string.find(match, "'", start + 1)

                        if start == -1 or end == -1:
                            raise se.AuthenticationFailed("could not extract key name (%s)" % match)

                        key = match[start + 1 : end]

                        if not key in key_pass:
                            raise se.AuthenticationFailed("prompted for unknown key password (%s)" % key)

                        pty_shell.write("%s\n" % key_pass[key], nolog=True)
                        n, match = pty_shell.find(prompt_patterns, delay)

                    # --------------------------------------------------------------
                    elif n == 2 or n == 3:
                        logger.info("got token prompt")
                        import getpass

                        token = getpass.getpass("enter token: ")
                        pty_shell.write("%s\n" % token.strip(), nolog=True)
                        n, match = pty_shell.find(prompt_patterns, delay)

                    # --------------------------------------------------------------
                    elif n == 4:
                        logger.info("got hostkey prompt")
                        pty_shell.write("yes\n")
                        n, match = pty_shell.find(prompt_patterns, delay)

                    # --------------------------------------------------------------
                    elif n == 5:

                        # one of the trigger commands got through -- we can now
                        # hope to find the prompt (or the next trigger...)
                        logger.debug("got shell prompt trigger (%s) (%s)" % (n, match))

                        found_trigger = match
                        retry_trigger = False
                        n, match = pty_shell.find(prompt_patterns, delay)
                        continue

                    # --------------------------------------------------------------
                    elif n == 6:

                        logger.debug("got initial shell prompt (%s) (%s)" % (n, match))

                        if retries:
                            if used_trigger:
                                # we already sent triggers -- so this match is only
                                # useful if saw the *correct* shell prompt trigger
                                # first
                                trigger = "HELLO_%d_SAGA" % retries

                                if not trigger in found_trigger:

                                    logger.debug("waiting for prompt trigger %s: (%s) (%s)" % (trigger, n, match))
                                    # but more retries won't help...
                                    retry_trigger = False
                                    attempts = 0
                                    n = None

                                    while not n:

                                        attempts += 1
                                        n, match = pty_shell.find(prompt_patterns, delay)

                                        if not n:
                                            if attempts == 1:
                                                if posix:
                                                    pty_shell.write(" printf 'HELLO_%%d_SAGA\\n' %d\n" % retries)

                                            if attempts > 100:
                                                raise se.NoSuccess("Could not detect shell prompt (timeout)")

                                    continue

                        logger.debug("Got initial shell prompt (%s) (%s)" % (n, match))
                        # we are done waiting for a prompt
                        break

            except Exception as e:
                logger.exception(e)
                raise ptye.translate_exception(e)

#.........这里部分代码省略.........
                            raise se.NoSuccess ("Could not detect shell prompt (timeout)")

                        if  not retry_trigger : 
                            # just waiting for the *right* trigger or prompt, 
                            # don't need new ones...
                            continue

                        retries += 1

                        if  is_shell :
                            # use a very aggressive, but portable prompt setting scheme
                            pty_shell.write ("export PS1='>' >& /dev/null || set prompt='>'\n")
                            pty_shell.write ("printf 'HELLO_%%d_SAGA\\n' %d\n" % retries)