third_party/pexpect/pexpect.py

   1 """Pexpect is a Python module for spawning child applications and controlling
   2 them automatically. Pexpect can be used for automating interactive applications
   3 such as ssh, ftp, passwd, telnet, etc. It can be used to a automate setup
   4 scripts for duplicating software package installations on different servers. It
   5 can be used for automated software testing. Pexpect is in the spirit of Don
   6 Libes' Expect, but Pexpect is pure Python. Other Expect-like modules for Python
   7 require TCL and Expect or require C extensions to be compiled. Pexpect does not
   8 use C, Expect, or TCL extensions. It should work on any platform that supports
   9 the standard Python pty module. The Pexpect interface focuses on ease of use so
  10 that simple tasks are easy.
  11
  12 There are two main interfaces to the Pexpect system; these are the function,
  13 run() and the class, spawn. The spawn class is more powerful. The run()
  14 function is simpler than spawn, and is good for quickly calling program. When
  15 you call the run() function it executes a given program and then returns the
  16 output. This is a handy replacement for os.system().
  17
  18 For example::
  19
  20     pexpect.run('ls -la')
  21
  22 The spawn class is the more powerful interface to the Pexpect system. You can
  23 use this to spawn a child program then interact with it by sending input and
  24 expecting responses (waiting for patterns in the child's output).
  25
  26 For example::
  27
  28     child = pexpect.spawn('scp foo user@example.com:.')
  29     child.expect('Password:')
  30     child.sendline(mypassword)
  31
  32 This works even for commands that ask for passwords or other input outside of
  33 the normal stdio streams. For example, ssh reads input directly from the TTY
  34 device which bypasses stdin.
  35
  36 Credits: Noah Spurrier, Richard Holden, Marco Molteni, Kimberley Burchett,
  37 Robert Stone, Hartmut Goebel, Chad Schroeder, Erick Tryzelaar, Dave Kirby, Ids
  38 vander Molen, George Todd, Noel Taylor, Nicolas D. Cesar, Alexander Gattin,
  39 Jacques-Etienne Baudoux, Geoffrey Marshall, Francisco Lourenco, Glen Mabey,
  40 Karthik Gurusamy, Fernando Perez, Corey Minyard, Jon Cohen, Guillaume
  41 Chazarain, Andrew Ryan, Nick Craig-Wood, Andrew Stone, Jorgen Grahn, John
  42 Spiegel, Jan Grant, and Shane Kerr. Let me know if I forgot anyone.
  43
  44 Pexpect is free, open source, and all that good stuff.
  45 http://pexpect.sourceforge.net/
  46
  47 PEXPECT LICENSE
  48
  49     This license is approved by the OSI and FSF as GPL-compatible.
  50         http://opensource.org/licenses/isc-license.txt
  51
  52     Copyright (c) 2012, Noah Spurrier <noah@noah.org>
  53     PERMISSION TO USE, COPY, MODIFY, AND/OR DISTRIBUTE THIS SOFTWARE FOR ANY
  54     PURPOSE WITH OR WITHOUT FEE IS HEREBY GRANTED, PROVIDED THAT THE ABOVE
  55     COPYRIGHT NOTICE AND THIS PERMISSION NOTICE APPEAR IN ALL COPIES.
  56     THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  57     WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  58     MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  59     ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  60     WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  61     ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  62     OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  63
  64 """
  65
  66 try:
  67     import os
  68     import sys
  69     import time
  70     import select
  71     import string
  72     import re
  73     import struct
  74     import resource
  75     import types
  76     import pty
  77     import tty
  78     import termios
  79     import fcntl
  80     import errno
  81     import traceback
  82     import signal
  83 except ImportError as e:
  84     raise ImportError(str(e) + """
  85
  86 A critical module was not found. Probably this operating system does not
  87 support it. Pexpect is intended for UNIX-like operating systems.""")
  88
  89 __version__ = '2.6'
  90 __revision__ = '1'
  91 __all__ = ['ExceptionPexpect', 'EOF', 'TIMEOUT', 'spawn', 'run', 'which',
  92     'split_command_line', '__version__', '__revision__']
  93
  94
  95 # Exception classes used by this module.
  96 class ExceptionPexpect(Exception):
  97
  98     """Base class for all exceptions raised by this module.
  99     """
 100
 101     def __init__(self, value):
 102
 103         self.value = value
 104
 105     def __str__(self):
 106
 107         return str(self.value)
 108
 109     def get_trace(self):
 110
 111         """This returns an abbreviated stack trace with lines that only concern
 112         the caller. In other words, the stack trace inside the Pexpect module
 113         is not included. """
 114
 115         tblist = traceback.extract_tb(sys.exc_info()[2])
 116         #tblist = filter(self.__filter_not_pexpect, tblist)
 117         tblist = [item for item in tblist if self.__filter_not_pexpect(item)]
 118         tblist = traceback.format_list(tblist)
 119         return ''.join(tblist)
 120
 121     def __filter_not_pexpect(self, trace_list_item):
 122
 123         """This returns True if list item 0 the string 'pexpect.py' in it. """
 124
 125         if trace_list_item[0].find('pexpect.py') == -1:
 126             return True
 127         else:
 128             return False
 129
 130
 131 class EOF(ExceptionPexpect):
 132
 133     """Raised when EOF is read from a child.
 134     This usually means the child has exited."""
 135
 136
 137 class TIMEOUT(ExceptionPexpect):
 138
 139     """Raised when a read time exceeds the timeout. """
 140
 141 ##class TIMEOUT_PATTERN(TIMEOUT):
 142 ##    """Raised when the pattern match time exceeds the timeout.
 143 ##    This is different than a read TIMEOUT because the child process may
 144 ##    give output, thus never give a TIMEOUT, but the output
 145 ##    may never match a pattern.
 146 ##    """
 147 ##class MAXBUFFER(ExceptionPexpect):
 148 ##    """Raised when a buffer fills before matching an expected pattern."""
 149
 150
 151 def run(command, timeout=-1, withexitstatus=False, events=None,
 152         extra_args=None, logfile=None, cwd=None, env=None):
 153
 154     """
 155     This function runs the given command; waits for it to finish; then
 156     returns all output as a string. STDERR is included in output. If the full
 157     path to the command is not given then the path is searched.
 158
 159     Note that lines are terminated by CR/LF (\\r\\n) combination even on
 160     UNIX-like systems because this is the standard for pseudottys. If you set
 161     'withexitstatus' to true, then run will return a tuple of (command_output,
 162     exitstatus). If 'withexitstatus' is false then this returns just
 163     command_output.
 164
 165     The run() function can often be used instead of creating a spawn instance.
 166     For example, the following code uses spawn::
 167
 168         from pexpect import *
 169         child = spawn('scp foo user@example.com:.')
 170         child.expect('(?i)password')
 171         child.sendline(mypassword)
 172
 173     The previous code can be replace with the following::
 174
 175         from pexpect import *
 176         run('scp foo user@example.com:.', events={'(?i)password': mypassword})
 177
 178     Examples
 179     ========
 180
 181     Start the apache daemon on the local machine::
 182
 183         from pexpect import *
 184         run("/usr/local/apache/bin/apachectl start")
 185
 186     Check in a file using SVN::
 187
 188         from pexpect import *
 189         run("svn ci -m 'automatic commit' my_file.py")
 190
 191     Run a command and capture exit status::
 192
 193         from pexpect import *
 194         (command_output, exitstatus) = run('ls -l /bin', withexitstatus=1)
 195
 196     Tricky Examples
 197     ===============
 198
 199     The following will run SSH and execute 'ls -l' on the remote machine. The
 200     password 'secret' will be sent if the '(?i)password' pattern is ever seen::
 201
 202         run("ssh username@machine.example.com 'ls -l'",
 203             events={'(?i)password':'secret\\n'})
 204
 205     This will start mencoder to rip a video from DVD. This will also display
 206     progress ticks every 5 seconds as it runs. For example::
 207
 208         from pexpect import *
 209         def print_ticks(d):
 210             print d['event_count'],
 211         run("mencoder dvd://1 -o video.avi -oac copy -ovc copy",
 212             events={TIMEOUT:print_ticks}, timeout=5)
 213
 214     The 'events' argument should be a dictionary of patterns and responses.
 215     Whenever one of the patterns is seen in the command out run() will send the
 216     associated response string. Note that you should put newlines in your
 217     string if Enter is necessary. The responses may also contain callback
 218     functions. Any callback is function that takes a dictionary as an argument.
 219     The dictionary contains all the locals from the run() function, so you can
 220     access the child spawn object or any other variable defined in run()
 221     (event_count, child, and extra_args are the most useful). A callback may
 222     return True to stop the current run process otherwise run() continues until
 223     the next event. A callback may also return a string which will be sent to
 224     the child. 'extra_args' is not used by directly run(). It provides a way to
 225     pass data to a callback function through run() through the locals
 226     dictionary passed to a callback. """
 227
 228     if timeout == -1:
 229         child = spawn(command, maxread=2000, logfile=logfile, cwd=cwd, env=env)
 230     else:
 231         child = spawn(command, timeout=timeout, maxread=2000, logfile=logfile,
 232                 cwd=cwd, env=env)
 233     if events is not None:
 234         patterns = list(events.keys())
 235         responses = list(events.values())
 236     else:
 237         # This assumes EOF or TIMEOUT will eventually cause run to terminate.
 238         patterns = None
 239         responses = None
 240     child_result_list = []
 241     event_count = 0
 242     while True:
 243         try:
 244             index = child.expect(patterns)
 245             if type(child.after) in types.StringTypes:
 246                 child_result_list.append(child.before + child.after)
 247             else:
 248                 # child.after may have been a TIMEOUT or EOF,
 249                 # which we don't want appended to the list.
 250                 child_result_list.append(child.before)
 251             if type(responses[index]) in types.StringTypes:
 252                 child.send(responses[index])
 253             elif isinstance(responses[index], types.FunctionType):
 254                 callback_result = responses[index](locals())
 255                 sys.stdout.flush()
 256                 if type(callback_result) in types.StringTypes:
 257                     child.send(callback_result)
 258                 elif callback_result:
 259                     break
 260             else:
 261                 raise TypeError('The callback must be a string or function.')
 262             event_count = event_count + 1
 263         except TIMEOUT as e:
 264             child_result_list.append(child.before)
 265             break
 266         except EOF as e:
 267             child_result_list.append(child.before)
 268             break
 269     child_result = ''.join(child_result_list)
 270     if withexitstatus:
 271         child.close()
 272         return (child_result, child.exitstatus)
 273     else:
 274         return child_result
 275
 276
 277 class spawn(object):
 278
 279     """This is the main class interface for Pexpect. Use this class to start
 280     and control child applications. """
 281
 282     def __init__(self, command, args=[], timeout=30, maxread=2000,
 283         searchwindowsize=None, logfile=None, cwd=None, env=None):
 284
 285         """This is the constructor. The command parameter may be a string that
 286         includes a command and any arguments to the command. For example::
 287
 288             child = pexpect.spawn('/usr/bin/ftp')
 289             child = pexpect.spawn('/usr/bin/ssh user@example.com')
 290             child = pexpect.spawn('ls -latr /tmp')
 291
 292         You may also construct it with a list of arguments like so::
 293
 294             child = pexpect.spawn('/usr/bin/ftp', [])
 295             child = pexpect.spawn('/usr/bin/ssh', ['user@example.com'])
 296             child = pexpect.spawn('ls', ['-latr', '/tmp'])
 297
 298         After this the child application will be created and will be ready to
 299         talk to. For normal use, see expect() and send() and sendline().
 300
 301         Remember that Pexpect does NOT interpret shell meta characters such as
 302         redirect, pipe, or wild cards (>, |, or *). This is a common mistake.
 303         If you want to run a command and pipe it through another command then
 304         you must also start a shell. For example::
 305
 306             child = pexpect.spawn('/bin/bash -c "ls -l | grep LOG > logs.txt"')
 307             child.expect(pexpect.EOF)
 308
 309         The second form of spawn (where you pass a list of arguments) is useful
 310         in situations where you wish to spawn a command and pass it its own
 311         argument list. This can make syntax more clear. For example, the
 312         following is equivalent to the previous example::
 313
 314             shell_cmd = 'ls -l | grep LOG > logs.txt'
 315             child = pexpect.spawn('/bin/bash', ['-c', shell_cmd])
 316             child.expect(pexpect.EOF)
 317
 318         The maxread attribute sets the read buffer size. This is maximum number
 319         of bytes that Pexpect will try to read from a TTY at one time. Setting
 320         the maxread size to 1 will turn off buffering. Setting the maxread
 321         value higher may help performance in cases where large amounts of
 322         output are read back from the child. This feature is useful in
 323         conjunction with searchwindowsize.
 324
 325         The searchwindowsize attribute sets the how far back in the incomming
 326         seach buffer Pexpect will search for pattern matches. Every time
 327         Pexpect reads some data from the child it will append the data to the
 328         incomming buffer. The default is to search from the beginning of the
 329         imcomming buffer each time new data is read from the child. But this is
 330         very inefficient if you are running a command that generates a large
 331         amount of data where you want to match The searchwindowsize does not
 332         effect the size of the incomming data buffer. You will still have
 333         access to the full buffer after expect() returns.
 334
 335         The logfile member turns on or off logging. All input and output will
 336         be copied to the given file object. Set logfile to None to stop
 337         logging. This is the default. Set logfile to sys.stdout to echo
 338         everything to standard output. The logfile is flushed after each write.
 339
 340         Example log input and output to a file::
 341
 342             child = pexpect.spawn('some_command')
 343             fout = file('mylog.txt','w')
 344             child.logfile = fout
 345
 346         Example log to stdout::
 347
 348             child = pexpect.spawn('some_command')
 349             child.logfile = sys.stdout
 350
 351         The logfile_read and logfile_send members can be used to separately log
 352         the input from the child and output sent to the child. Sometimes you
 353         don't want to see everything you write to the child. You only want to
 354         log what the child sends back. For example::
 355
 356             child = pexpect.spawn('some_command')
 357             child.logfile_read = sys.stdout
 358
 359         To separately log output sent to the child use logfile_send::
 360
 361             self.logfile_send = fout
 362
 363         The delaybeforesend helps overcome a weird behavior that many users
 364         were experiencing. The typical problem was that a user would expect() a
 365         "Password:" prompt and then immediately call sendline() to send the
 366         password. The user would then see that their password was echoed back
 367         to them. Passwords don't normally echo. The problem is caused by the
 368         fact that most applications print out the "Password" prompt and then
 369         turn off stdin echo, but if you send your password before the
 370         application turned off echo, then you get your password echoed.
 371         Normally this wouldn't be a problem when interacting with a human at a
 372         real keyboard. If you introduce a slight delay just before writing then
 373         this seems to clear up the problem. This was such a common problem for
 374         many users that I decided that the default pexpect behavior should be
 375         to sleep just before writing to the child application. 1/20th of a
 376         second (50 ms) seems to be enough to clear up the problem. You can set
 377         delaybeforesend to 0 to return to the old behavior. Most Linux machines
 378         don't like this to be below 0.03. I don't know why.
 379
 380         Note that spawn is clever about finding commands on your path.
 381         It uses the same logic that "which" uses to find executables.
 382
 383         If you wish to get the exit status of the child you must call the
 384         close() method. The exit or signal status of the child will be stored
 385         in self.exitstatus or self.signalstatus. If the child exited normally
 386         then exitstatus will store the exit return code and signalstatus will
 387         be None. If the child was terminated abnormally with a signal then
 388         signalstatus will store the signal value and exitstatus will be None.
 389         If you need more detail you can also read the self.status member which
 390         stores the status returned by os.waitpid. You can interpret this using
 391         os.WIFEXITED/os.WEXITSTATUS or os.WIFSIGNALED/os.TERMSIG. """
 392
 393         self.STDIN_FILENO = pty.STDIN_FILENO
 394         self.STDOUT_FILENO = pty.STDOUT_FILENO
 395         self.STDERR_FILENO = pty.STDERR_FILENO
 396         self.stdin = sys.stdin
 397         self.stdout = sys.stdout
 398         self.stderr = sys.stderr
 399
 400         self.searcher = None
 401         self.ignorecase = False
 402         self.before = None
 403         self.after = None
 404         self.match = None
 405         self.match_index = None
 406         self.terminated = True
 407         self.exitstatus = None
 408         self.signalstatus = None
 409         # status returned by os.waitpid
 410         self.status = None
 411         self.flag_eof = False
 412         self.pid = None
 413         # the chile filedescriptor is initially closed
 414         self.child_fd = -1
 415         self.timeout = timeout
 416         self.delimiter = EOF
 417         self.logfile = logfile
 418         # input from child (read_nonblocking)
 419         self.logfile_read = None
 420         # output to send (send, sendline)
 421         self.logfile_send = None
 422         # max bytes to read at one time into buffer
 423         self.maxread = maxread
 424         # This is the read buffer. See maxread.
 425         self.buffer = ''
 426         # Data before searchwindowsize point is preserved, but not searched.
 427         self.searchwindowsize = searchwindowsize
 428         # Delay used before sending data to child. Time in seconds.
 429         # Most Linux machines don't like this to be below 0.03 (30 ms).
 430         self.delaybeforesend = 0.05
 431         # Used by close() to give kernel time to update process status.
 432         # Time in seconds.
 433         self.delayafterclose = 0.1
 434         # Used by terminate() to give kernel time to update process status.
 435         # Time in seconds.
 436         self.delayafterterminate = 0.1
 437         self.softspace = False
 438         self.name = '<' + repr(self) + '>'
 439         self.encoding = None
 440         self.closed = True
 441         self.cwd = cwd
 442         self.env = env
 443         # This flags if we are running on irix
 444         self.__irix_hack = (sys.platform.lower().find('irix') >= 0)
 445         # Solaris uses internal __fork_pty(). All others use pty.fork().
 446         if ((sys.platform.lower().find('solaris') >= 0)
 447             or (sys.platform.lower().find('sunos5') >= 0)):
 448             self.use_native_pty_fork = False
 449         else:
 450             self.use_native_pty_fork = True
 451
 452         # Support subclasses that do not use command or args.
 453         if command is None:
 454             self.command = None
 455             self.args = None
 456             self.name = '<pexpect factory incomplete>'
 457         else:
 458             self._spawn(command, args)
 459
 460     def __del__(self):
 461
 462         """This makes sure that no system resources are left open. Python only
 463         garbage collects Python objects. OS file descriptors are not Python
 464         objects, so they must be handled explicitly. If the child file
 465         descriptor was opened outside of this class (passed to the constructor)
 466         then this does not close it. """
 467
 468         if not self.closed:
 469             # It is possible for __del__ methods to execute during the
 470             # teardown of the Python VM itself. Thus self.close() may
 471             # trigger an exception because os.close may be None.
 472             # -- Fernando Perez
 473             try:
 474                 self.close()
 475             except:
 476                 pass
 477
 478     def __str__(self):
 479
 480         """This returns a human-readable string that represents the state of
 481         the object. """
 482
 483         s = []
 484         s.append(repr(self))
 485         s.append('version: ' + __version__ + ' (' + __revision__ + ')')
 486         s.append('command: ' + str(self.command))
 487         s.append('args: ' + str(self.args))
 488         s.append('searcher: ' + str(self.searcher))
 489         s.append('buffer (last 100 chars): ' + str(self.buffer)[-100:])
 490         s.append('before (last 100 chars): ' + str(self.before)[-100:])
 491         s.append('after: ' + str(self.after))
 492         s.append('match: ' + str(self.match))
 493         s.append('match_index: ' + str(self.match_index))
 494         s.append('exitstatus: ' + str(self.exitstatus))
 495         s.append('flag_eof: ' + str(self.flag_eof))
 496         s.append('pid: ' + str(self.pid))
 497         s.append('child_fd: ' + str(self.child_fd))
 498         s.append('closed: ' + str(self.closed))
 499         s.append('timeout: ' + str(self.timeout))
 500         s.append('delimiter: ' + str(self.delimiter))
 501         s.append('logfile: ' + str(self.logfile))
 502         s.append('logfile_read: ' + str(self.logfile_read))
 503         s.append('logfile_send: ' + str(self.logfile_send))
 504         s.append('maxread: ' + str(self.maxread))
 505         s.append('ignorecase: ' + str(self.ignorecase))
 506         s.append('searchwindowsize: ' + str(self.searchwindowsize))
 507         s.append('delaybeforesend: ' + str(self.delaybeforesend))
 508         s.append('delayafterclose: ' + str(self.delayafterclose))
 509         s.append('delayafterterminate: ' + str(self.delayafterterminate))
 510         return '\n'.join(s)
 511
 512     def _spawn(self, command, args=[]):
 513
 514         """This starts the given command in a child process. This does all the
 515         fork/exec type of stuff for a pty. This is called by __init__. If args
 516         is empty then command will be parsed (split on spaces) and args will be
 517         set to parsed arguments. """
 518
 519         # The pid and child_fd of this object get set by this method.
 520         # Note that it is difficult for this method to fail.
 521         # You cannot detect if the child process cannot start.
 522         # So the only way you can tell if the child process started
 523         # or not is to try to read from the file descriptor. If you get
 524         # EOF immediately then it means that the child is already dead.
 525         # That may not necessarily be bad because you may have spawned a child
 526         # that performs some task; creates no stdout output; and then dies.
 527
 528         # If command is an int type then it may represent a file descriptor.
 529         if isinstance(command, type(0)):
 530             raise ExceptionPexpect('Command is an int type. ' +
 531                     'If this is a file descriptor then maybe you want to ' +
 532                     'use fdpexpect.fdspawn which takes an existing ' +
 533                     'file descriptor instead of a command string.')
 534
 535         if not isinstance(args, type([])):
 536             raise TypeError('The argument, args, must be a list.')
 537
 538         if args == []:
 539             self.args = split_command_line(command)
 540             self.command = self.args[0]
 541         else:
 542             # Make a shallow copy of the args list.
 543             self.args = args[:]
 544             self.args.insert(0, command)
 545             self.command = command
 546
 547         command_with_path = which(self.command)
 548         if command_with_path is None:
 549             raise ExceptionPexpect('The command was not found or was not ' +
 550                     'executable: %s.' % self.command)
 551         self.command = command_with_path
 552         self.args[0] = self.command
 553
 554         self.name = '<' + ' '.join(self.args) + '>'
 555
 556         assert self.pid is None, 'The pid member must be None.'
 557         assert self.command is not None, 'The command member must not be None.'
 558
 559         if self.use_native_pty_fork:
 560             try:
 561                 self.pid, self.child_fd = pty.fork()
 562             except OSError as e:
 563                 raise ExceptionPexpect('pty.fork() failed: ' + str(e))
 564         else:
 565             # Use internal __fork_pty
 566             self.pid, self.child_fd = self.__fork_pty()
 567
 568         if self.pid == 0:
 569             # Child
 570             try:
 571                 # used by setwinsize()
 572                 self.child_fd = sys.stdout.fileno()
 573                 self.setwinsize(24, 80)
 574             except:
 575                 # Some platforms do not like setwinsize (Cygwin).
 576                 # This will cause problem when running applications that
 577                 # are very picky about window size.
 578                 # This is a serious limitation, but not a show stopper.
 579                 pass
 580             # Do not allow child to inherit open file descriptors from parent.
 581             max_fd = resource.getrlimit(resource.RLIMIT_NOFILE)[0]
 582             for i in range(3, max_fd):
 583                 try:
 584                     os.close(i)
 585                 except OSError:
 586                     pass
 587
 588             # I don't know why this works, but ignoring SIGHUP fixes a
 589             # problem when trying to start a Java daemon with sudo
 590             # (specifically, Tomcat).
 591             signal.signal(signal.SIGHUP, signal.SIG_IGN)
 592
 593             if self.cwd is not None:
 594                 os.chdir(self.cwd)
 595             if self.env is None:
 596                 os.execv(self.command, self.args)
 597             else:
 598                 os.execvpe(self.command, self.args, self.env)
 599
 600         # Parent
 601         self.terminated = False
 602         self.closed = False
 603
 604     def __fork_pty(self):
 605
 606         """This implements a substitute for the forkpty system call. This
 607         should be more portable than the pty.fork() function. Specifically,
 608         this should work on Solaris.
 609
 610         Modified 10.06.05 by Geoff Marshall: Implemented __fork_pty() method to
 611         resolve the issue with Python's pty.fork() not supporting Solaris,
 612         particularly ssh. Based on patch to posixmodule.c authored by Noah
 613         Spurrier::
 614
 615             http://mail.python.org/pipermail/python-dev/2003-May/035281.html
 616
 617         """
 618
 619         parent_fd, child_fd = os.openpty()
 620         if parent_fd < 0 or child_fd < 0:
 621             raise ExceptionPexpect("Could not open with os.openpty().")
 622
 623         pid = os.fork()
 624         if pid < 0:
 625             raise ExceptionPexpect("Failed os.fork().")
 626         elif pid == 0:
 627             # Child.
 628             os.close(parent_fd)
 629             self.__pty_make_controlling_tty(child_fd)
 630
 631             os.dup2(child_fd, 0)
 632             os.dup2(child_fd, 1)
 633             os.dup2(child_fd, 2)
 634
 635             if child_fd > 2:
 636                 os.close(child_fd)
 637         else:
 638             # Parent.
 639             os.close(child_fd)
 640
 641         return pid, parent_fd
 642
 643     def __pty_make_controlling_tty(self, tty_fd):
 644
 645         """This makes the pseudo-terminal the controlling tty. This should be
 646         more portable than the pty.fork() function. Specifically, this should
 647         work on Solaris. """
 648
 649         child_name = os.ttyname(tty_fd)
 650
 651         # Disconnect from controlling tty. Harmless if not already connected.
 652         try:
 653             fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY)
 654             if fd >= 0:
 655                 os.close(fd)
 656         except:
 657             # Already disconnected. This happens if running inside cron.
 658             pass
 659
 660         os.setsid()
 661
 662         # Verify we are disconnected from controlling tty
 663         # by attempting to open it again.
 664         try:
 665             fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY)
 666             if fd >= 0:
 667                 os.close(fd)
 668                 raise ExceptionPexpect('Failed to disconnect from ' +
 669                     'controlling tty. It is still possible to open /dev/tty.')
 670         except:
 671             # Good! We are disconnected from a controlling tty.
 672             pass
 673
 674         # Verify we can open child pty.
 675         fd = os.open(child_name, os.O_RDWR)
 676         if fd < 0:
 677             raise ExceptionPexpect("Could not open child pty, " + child_name)
 678         else:
 679             os.close(fd)
 680
 681         # Verify we now have a controlling tty.
 682         fd = os.open("/dev/tty", os.O_WRONLY)
 683         if fd < 0:
 684             raise ExceptionPexpect("Could not open controlling tty, /dev/tty")
 685         else:
 686             os.close(fd)
 687
 688     def fileno(self):
 689
 690         """This returns the file descriptor of the pty for the child.
 691         """
 692
 693         return self.child_fd
 694
 695     def close(self, force=True):
 696
 697         """This closes the connection with the child application. Note that
 698         calling close() more than once is valid. This emulates standard Python
 699         behavior with files. Set force to True if you want to make sure that
 700         the child is terminated (SIGKILL is sent if the child ignores SIGHUP
 701         and SIGINT). """
 702
 703         if not self.closed:
 704             self.flush()
 705             os.close(self.child_fd)
 706             # Give kernel time to update process status.
 707             time.sleep(self.delayafterclose)
 708             if self.isalive():
 709                 if not self.terminate(force):
 710                     raise ExceptionPexpect('Could not terminate the child.')
 711             self.child_fd = -1
 712             self.closed = True
 713             #self.pid = None
 714
 715     def flush(self):
 716
 717         """This does nothing. It is here to support the interface for a
 718         File-like object. """
 719
 720         pass
 721
 722     def isatty(self):
 723
 724         """This returns True if the file descriptor is open and connected to a
 725         tty(-like) device, else False. """
 726
 727         return os.isatty(self.child_fd)
 728
 729     def waitnoecho(self, timeout=-1):
 730
 731         """This waits until the terminal ECHO flag is set False. This returns
 732         True if the echo mode is off. This returns False if the ECHO flag was
 733         not set False before the timeout. This can be used to detect when the
 734         child is waiting for a password. Usually a child application will turn
 735         off echo mode when it is waiting for the user to enter a password. For
 736         example, instead of expecting the "password:" prompt you can wait for
 737         the child to set ECHO off::
 738
 739             p = pexpect.spawn('ssh user@example.com')
 740             p.waitnoecho()
 741             p.sendline(mypassword)
 742
 743         If timeout==-1 then this method will use the value in self.timeout.
 744         If timeout==None then this method to block until ECHO flag is False.
 745         """
 746
 747         if timeout == -1:
 748             timeout = self.timeout
 749         if timeout is not None:
 750             end_time = time.time() + timeout
 751         while True:
 752             if not self.getecho():
 753                 return True
 754             if timeout < 0 and timeout is not None:
 755                 return False
 756             if timeout is not None:
 757                 timeout = end_time - time.time()
 758             time.sleep(0.1)
 759
 760     def getecho(self):
 761
 762         """This returns the terminal echo mode. This returns True if echo is
 763         on or False if echo is off. Child applications that are expecting you
 764         to enter a password often set ECHO False. See waitnoecho(). """
 765
 766         attr = termios.tcgetattr(self.child_fd)
 767         if attr[3] & termios.ECHO:
 768             return True
 769         return False
 770
 771     def setecho(self, state):
 772
 773         """This sets the terminal echo mode on or off. Note that anything the
 774         child sent before the echo will be lost, so you should be sure that
 775         your input buffer is empty before you call setecho(). For example, the
 776         following will work as expected::
 777
 778             p = pexpect.spawn('cat') # Echo is on by default.
 779             p.sendline('1234') # We expect see this twice from the child...
 780             p.expect(['1234']) # ... once from the tty echo...
 781             p.expect(['1234']) # ... and again from cat itself.
 782             p.setecho(False) # Turn off tty echo
 783             p.sendline('abcd') # We will set this only once (echoed by cat).
 784             p.sendline('wxyz') # We will set this only once (echoed by cat)
 785             p.expect(['abcd'])
 786             p.expect(['wxyz'])
 787
 788         The following WILL NOT WORK because the lines sent before the setecho
 789         will be lost::
 790
 791             p = pexpect.spawn('cat')
 792             p.sendline('1234')
 793             p.setecho(False) # Turn off tty echo
 794             p.sendline('abcd') # We will set this only once (echoed by cat).
 795             p.sendline('wxyz') # We will set this only once (echoed by cat)
 796             p.expect(['1234'])
 797             p.expect(['1234'])
 798             p.expect(['abcd'])
 799             p.expect(['wxyz'])
 800         """
 801
 802         self.child_fd
 803         attr = termios.tcgetattr(self.child_fd)
 804         if state:
 805             attr[3] = attr[3] | termios.ECHO
 806         else:
 807             attr[3] = attr[3] & ~termios.ECHO
 808         # I tried TCSADRAIN and TCSAFLUSH, but
 809         # these were inconsistent and blocked on some platforms.
 810         # TCSADRAIN would probably be ideal if it worked.
 811         termios.tcsetattr(self.child_fd, termios.TCSANOW, attr)
 812
 813     def read_nonblocking(self, size=1, timeout=-1):
 814
 815         """This reads at most size characters from the child application. It
 816         includes a timeout. If the read does not complete within the timeout
 817         period then a TIMEOUT exception is raised. If the end of file is read
 818         then an EOF exception will be raised. If a log file was set using
 819         setlog() then all data will also be written to the log file.
 820
 821         If timeout is None then the read may block indefinitely.
 822         If timeout is -1 then the self.timeout value is used. If timeout is 0
 823         then the child is polled and if there is no data immediately ready
 824         then this will raise a TIMEOUT exception.
 825
 826         The timeout refers only to the amount of time to read at least one
 827         character. This is not effected by the 'size' parameter, so if you call
 828         read_nonblocking(size=100, timeout=30) and only one character is
 829         available right away then one character will be returned immediately.
 830         It will not wait for 30 seconds for another 99 characters to come in.
 831
 832         This is a wrapper around os.read(). It uses select.select() to
 833         implement the timeout. """
 834
 835         if self.closed:
 836             raise ValueError('I/O operation on closed file.')
 837
 838         if timeout == -1:
 839             timeout = self.timeout
 840
 841         # Note that some systems such as Solaris do not give an EOF when
 842         # the child dies. In fact, you can still try to read
 843         # from the child_fd -- it will block forever or until TIMEOUT.
 844         # For this case, I test isalive() before doing any reading.
 845         # If isalive() is false, then I pretend that this is the same as EOF.
 846         if not self.isalive():
 847             # timeout of 0 means "poll"
 848             r, w, e = self.__select([self.child_fd], [], [], 0)
 849             if not r:
 850                 self.flag_eof = True
 851                 raise EOF('End Of File (EOF). Braindead platform.')
 852         elif self.__irix_hack:
 853             # Irix takes a long time before it realizes a child was terminated.
 854             # FIXME So does this mean Irix systems are forced to always have
 855             # FIXME a 2 second delay when calling read_nonblocking? That sucks.
 856             r, w, e = self.__select([self.child_fd], [], [], 2)
 857             if not r and not self.isalive():
 858                 self.flag_eof = True
 859                 raise EOF('End Of File (EOF). Slow platform.')
 860
 861         r, w, e = self.__select([self.child_fd], [], [], timeout)
 862
 863         if not r:
 864             if not self.isalive():
 865                 # Some platforms, such as Irix, will claim that their
 866                 # processes are alive; timeout on the select; and
 867                 # then finally admit that they are not alive.
 868                 self.flag_eof = True
 869                 raise EOF('End of File (EOF). Very slow platform.')
 870             else:
 871                 raise TIMEOUT('Timeout exceeded.')
 872
 873         if self.child_fd in r:
 874             try:
 875                 s = os.read(self.child_fd, size)
 876             except OSError as e:
 877                 # Linux does this
 878                 self.flag_eof = True
 879                 raise EOF('End Of File (EOF). Exception style platform.')
 880             if s == '':
 881                 # BSD style
 882                 self.flag_eof = True
 883                 raise EOF('End Of File (EOF). Empty string style platform.')
 884             if self.logfile is not None:
 885                 self.logfile.write(s)
 886                 self.logfile.flush()
 887             if self.logfile_read is not None:
 888                 self.logfile_read.write(s)
 889                 self.logfile_read.flush()
 890             return s
 891
 892         raise ExceptionPexpect('Reached an unexpected state.')
 893
 894     def read(self, size=-1):
 895
 896         """This reads at most "size" bytes from the file (less if the read hits
 897         EOF before obtaining size bytes). If the size argument is negative or
 898         omitted, read all data until EOF is reached. The bytes are returned as
 899         a string object. An empty string is returned when EOF is encountered
 900         immediately. """
 901
 902         if size == 0:
 903             return ''
 904         if size < 0:
 905             # delimiter default is EOF
 906             self.expect(self.delimiter)
 907             return self.before
 908
 909         # I could have done this more directly by not using expect(), but
 910         # I deliberately decided to couple read() to expect() so that
 911         # I would catch any bugs early and ensure consistant behavior.
 912         # It's a little less efficient, but there is less for me to
 913         # worry about if I have to later modify read() or expect().
 914         # Note, it's OK if size==-1 in the regex. That just means it
 915         # will never match anything in which case we stop only on EOF.
 916         cre = re.compile('.{%d}' % size, re.DOTALL)
 917         # delimiter default is EOF
 918         index = self.expect([cre, self.delimiter])
 919         if index == 0:
 920             ### FIXME self.before should be ''. Should I assert this?
 921             return self.after
 922         return self.before
 923
 924     def readline(self, size=-1):
 925
 926         """This reads and returns one entire line. The newline at the end of
 927         line is returned as part of the string, unless the file ends without a
 928         newline. An empty string is returned if EOF is encountered immediately.
 929         This looks for a newline as a CR/LF pair (\\r\\n) even on UNIX because
 930         this is what the pseudotty device returns. So contrary to what you may
 931         expect you will receive newlines as \\r\\n.
 932
 933         If the size argument is 0 then an empty string is returned. In all
 934         other cases the size argument is ignored, which is not standard
 935         behavior for a file-like object. """
 936
 937         if size == 0:
 938             return ''
 939         # delimiter default is EOF
 940         index = self.expect(['\r\n', self.delimiter])
 941         if index == 0:
 942             return self.before + '\r\n'
 943         else:
 944             return self.before
 945
 946     def __iter__(self):
 947
 948         """This is to support iterators over a file-like object.
 949         """
 950
 951         return self
 952
 953     def __next__(self):
 954
 955         """This is to support iterators over a file-like object.
 956         """
 957
 958         result = self.readline()
 959         if result == "":
 960             raise StopIteration
 961         return result
 962
 963     def readlines(self, sizehint=-1):
 964
 965         """This reads until EOF using readline() and returns a list containing
 966         the lines thus read. The optional 'sizehint' argument is ignored. """
 967
 968         lines = []
 969         while True:
 970             line = self.readline()
 971             if not line:
 972                 break
 973             lines.append(line)
 974         return lines
 975
 976     def write(self, s):
 977
 978         """This is similar to send() except that there is no return value.
 979         """
 980
 981         self.send(s)
 982
 983     def writelines(self, sequence):
 984
 985         """This calls write() for each element in the sequence. The sequence
 986         can be any iterable object producing strings, typically a list of
 987         strings. This does not add line separators There is no return value.
 988         """
 989
 990         for s in sequence:
 991             self.write(s)
 992
 993     def send(self, s):
 994
 995         """This sends a string to the child process. This returns the number of
 996         bytes written. If a log file was set then the data is also written to
 997         the log. """
 998
 999         time.sleep(self.delaybeforesend)
1000         if self.logfile is not None:
1001             self.logfile.write(s)
1002             self.logfile.flush()
1003         if self.logfile_send is not None:
1004             self.logfile_send.write(s)
1005             self.logfile_send.flush()
1006         c = os.write(self.child_fd, s.encode("utf-8"))
1007         return c
1008
1009     def sendline(self, s=''):
1010
1011         """This is like send(), but it adds a linefeed (os.linesep). This
1012         returns the number of bytes written. """
1013
1014         n = self.send(s)
1015         n = n + self.send(os.linesep)
1016         return n
1017
1018     def sendcontrol(self, char):
1019
1020         """This sends a control character to the child such as Ctrl-C or
1021         Ctrl-D. For example, to send a Ctrl-G (ASCII 7)::
1022
1023             child.sendcontrol('g')
1024
1025         See also, sendintr() and sendeof().
1026         """
1027
1028         char = char.lower()
1029         a = ord(char)
1030         if a >= 97 and a <= 122:
1031             a = a - ord('a') + 1
1032             return self.send(chr(a))
1033         d = {'@': 0, '`': 0,
1034             '[': 27, '{': 27,
1035             '\\': 28, '|': 28,
1036             ']': 29, '}': 29,
1037             '^': 30, '~': 30,
1038             '_': 31,
1039             '?': 127}
1040         if char not in d:
1041             return 0
1042         return self.send(chr(d[char]))
1043
1044     def sendeof(self):
1045
1046         """This sends an EOF to the child. This sends a character which causes
1047         the pending parent output buffer to be sent to the waiting child
1048         program without waiting for end-of-line. If it is the first character
1049         of the line, the read() in the user program returns 0, which signifies
1050         end-of-file. This means to work as expected a sendeof() has to be
1051         called at the beginning of a line. This method does not send a newline.
1052         It is the responsibility of the caller to ensure the eof is sent at the
1053         beginning of a line. """
1054
1055         ### Hmmm... how do I send an EOF?
1056         ###C  if ((m = write(pty, *buf, p - *buf)) < 0)
1057         ###C      return (errno == EWOULDBLOCK) ? n : -1;
1058         #fd = sys.stdin.fileno()
1059         #old = termios.tcgetattr(fd) # remember current state
1060         #attr = termios.tcgetattr(fd)
1061         #attr[3] = attr[3] | termios.ICANON # ICANON must be set to see EOF
1062         #try: # use try/finally to ensure state gets restored
1063         #    termios.tcsetattr(fd, termios.TCSADRAIN, attr)
1064         #    if hasattr(termios, 'CEOF'):
1065         #        os.write(self.child_fd, '%c' % termios.CEOF)
1066         #    else:
1067         #        # Silly platform does not define CEOF so assume CTRL-D
1068         #        os.write(self.child_fd, '%c' % 4)
1069         #finally: # restore state
1070         #    termios.tcsetattr(fd, termios.TCSADRAIN, old)
1071         if hasattr(termios, 'VEOF'):
1072             char = termios.tcgetattr(self.child_fd)[6][termios.VEOF]
1073         else:
1074             # platform does not define VEOF so assume CTRL-D
1075             char = chr(4)
1076         self.send(char)
1077
1078     def sendintr(self):
1079
1080         """This sends a SIGINT to the child. It does not require
1081         the SIGINT to be the first character on a line. """
1082
1083         if hasattr(termios, 'VINTR'):
1084             char = termios.tcgetattr(self.child_fd)[6][termios.VINTR]
1085         else:
1086             # platform does not define VINTR so assume CTRL-C
1087             char = chr(3)
1088         self.send(char)
1089
1090     def eof(self):
1091
1092         """This returns True if the EOF exception was ever raised.
1093         """
1094
1095         return self.flag_eof
1096
1097     def terminate(self, force=False):
1098
1099         """This forces a child process to terminate. It starts nicely with
1100         SIGHUP and SIGINT. If "force" is True then moves onto SIGKILL. This
1101         returns True if the child was terminated. This returns False if the
1102         child could not be terminated. """
1103
1104         if not self.isalive():
1105             return True
1106         try:
1107             self.kill(signal.SIGHUP)
1108             time.sleep(self.delayafterterminate)
1109             if not self.isalive():
1110                 return True
1111             self.kill(signal.SIGCONT)
1112             time.sleep(self.delayafterterminate)
1113             if not self.isalive():
1114                 return True
1115             self.kill(signal.SIGINT)
1116             time.sleep(self.delayafterterminate)
1117             if not self.isalive():
1118                 return True
1119             if force:
1120                 self.kill(signal.SIGKILL)
1121                 time.sleep(self.delayafterterminate)
1122                 if not self.isalive():
1123                     return True
1124                 else:
1125                     return False
1126             return False
1127         except OSError as e:
1128             # I think there are kernel timing issues that sometimes cause
1129             # this to happen. I think isalive() reports True, but the
1130             # process is dead to the kernel.
1131             # Make one last attempt to see if the kernel is up to date.
1132             time.sleep(self.delayafterterminate)
1133             if not self.isalive():
1134                 return True
1135             else:
1136                 return False
1137
1138     def wait(self):
1139
1140         """This waits until the child exits. This is a blocking call. This will
1141         not read any data from the child, so this will block forever if the
1142         child has unread output and has terminated. In other words, the child
1143         may have printed output then called exit(), but, the child is
1144         technically still alive until its output is read by the parent. """
1145
1146         if self.isalive():
1147             pid, status = os.waitpid(self.pid, 0)
1148         else:
1149             raise ExceptionPexpect('Cannot wait for dead child process.')
1150         self.exitstatus = os.WEXITSTATUS(status)
1151         if os.WIFEXITED(status):
1152             self.status = status
1153             self.exitstatus = os.WEXITSTATUS(status)
1154             self.signalstatus = None
1155             self.terminated = True
1156         elif os.WIFSIGNALED(status):
1157             self.status = status
1158             self.exitstatus = None
1159             self.signalstatus = os.WTERMSIG(status)
1160             self.terminated = True
1161         elif os.WIFSTOPPED(status):
1162             # You can't call wait() on a child process in the stopped state.
1163             raise ExceptionPexpect('Called wait() on a stopped child ' +
1164                     'process. This is not supported. Is some other ' +
1165                     'process attempting job control with our child pid?')
1166         return self.exitstatus
1167
1168     def isalive(self):
1169
1170         """This tests if the child process is running or not. This is
1171         non-blocking. If the child was terminated then this will read the
1172         exitstatus or signalstatus of the child. This returns True if the child
1173         process appears to be running or False if not. It can take literally
1174         SECONDS for Solaris to return the right status. """
1175
1176         if self.terminated:
1177             return False
1178
1179         if self.flag_eof:
1180             # This is for Linux, which requires the blocking form
1181             # of waitpid to # get status of a defunct process.
1182             # This is super-lame. The flag_eof would have been set
1183             # in read_nonblocking(), so this should be safe.
1184             waitpid_options = 0
1185         else:
1186             waitpid_options = os.WNOHANG
1187
1188         try:
1189             pid, status = os.waitpid(self.pid, waitpid_options)
1190         except OSError as e:
1191             # No child processes
1192             if e[0] == errno.ECHILD:
1193                 raise ExceptionPexpect('isalive() encountered condition ' +
1194                         'where "terminated" is 0, but there was no child ' +
1195                         'process. Did someone else call waitpid() ' +
1196                         'on our process?')
1197             else:
1198                 raise e
1199
1200         # I have to do this twice for Solaris.
1201         # I can't even believe that I figured this out...
1202         # If waitpid() returns 0 it means that no child process
1203         # wishes to report, and the value of status is undefined.
1204         if pid == 0:
1205             try:
1206                 ### os.WNOHANG) # Solaris!
1207                 pid, status = os.waitpid(self.pid, waitpid_options)
1208             except OSError as e:
1209                 # This should never happen...
1210                 if e[0] == errno.ECHILD:
1211                     raise ExceptionPexpect('isalive() encountered condition ' +
1212                             'that should never happen. There was no child ' +
1213                             'process. Did someone else call waitpid() ' +
1214                             'on our process?')
1215                 else:
1216                     raise e
1217
1218             # If pid is still 0 after two calls to waitpid() then the process
1219             # really is alive. This seems to work on all platforms, except for
1220             # Irix which seems to require a blocking call on waitpid or select,
1221             # so I let read_nonblocking take care of this situation
1222             # (unfortunately, this requires waiting through the timeout).
1223             if pid == 0:
1224                 return True
1225
1226         if pid == 0:
1227             return True
1228
1229         if os.WIFEXITED(status):
1230             self.status = status
1231             self.exitstatus = os.WEXITSTATUS(status)
1232             self.signalstatus = None
1233             self.terminated = True
1234         elif os.WIFSIGNALED(status):
1235             self.status = status
1236             self.exitstatus = None
1237             self.signalstatus = os.WTERMSIG(status)
1238             self.terminated = True
1239         elif os.WIFSTOPPED(status):
1240             raise ExceptionPexpect('isalive() encountered condition ' +
1241                     'where child process is stopped. This is not ' +
1242                     'supported. Is some other process attempting ' +
1243                     'job control with our child pid?')
1244         return False
1245
1246     def kill(self, sig):
1247
1248         """This sends the given signal to the child application. In keeping
1249         with UNIX tradition it has a misleading name. It does not necessarily
1250         kill the child unless you send the right signal. """
1251
1252         # Same as os.kill, but the pid is given for you.
1253         if self.isalive():
1254             os.kill(self.pid, sig)
1255
1256     def compile_pattern_list(self, patterns):
1257
1258         """This compiles a pattern-string or a list of pattern-strings.
1259         Patterns must be a StringType, EOF, TIMEOUT, SRE_Pattern, or a list of
1260         those. Patterns may also be None which results in an empty list (you
1261         might do this if waiting for an EOF or TIMEOUT condition without
1262         expecting any pattern).
1263
1264         This is used by expect() when calling expect_list(). Thus expect() is
1265         nothing more than::
1266
1267              cpl = self.compile_pattern_list(pl)
1268              return self.expect_list(cpl, timeout)
1269
1270         If you are using expect() within a loop it may be more
1271         efficient to compile the patterns first and then call expect_list().
1272         This avoid calls in a loop to compile_pattern_list()::
1273
1274              cpl = self.compile_pattern_list(my_pattern)
1275              while some_condition:
1276                 ...
1277                 i = self.expect_list(clp, timeout)
1278                 ...
1279         """
1280
1281         if patterns is None:
1282             return []
1283         if not isinstance(patterns, list):
1284             patterns = [patterns]
1285
1286         # Allow dot to match \n
1287         compile_flags = re.DOTALL
1288         if self.ignorecase:
1289             compile_flags = compile_flags | re.IGNORECASE
1290         compiled_pattern_list = []
1291         for p in patterns:
1292             if type(p) in types.StringTypes:
1293                 compiled_pattern_list.append(re.compile(p, compile_flags))
1294             elif p is EOF:
1295                 compiled_pattern_list.append(EOF)
1296             elif p is TIMEOUT:
1297                 compiled_pattern_list.append(TIMEOUT)
1298             elif isinstance(p, type(re.compile(''))):
1299                 compiled_pattern_list.append(p)
1300             else:
1301                 raise TypeError('Argument must be one of StringTypes, ' +
1302                         'EOF, TIMEOUT, SRE_Pattern, or a list of those ' +
1303                         'type. %s' % str(type(p)))
1304
1305         return compiled_pattern_list
1306
1307     def expect(self, pattern, timeout=-1, searchwindowsize=-1):
1308
1309         """This seeks through the stream until a pattern is matched. The
1310         pattern is overloaded and may take several types. The pattern can be a
1311         StringType, EOF, a compiled re, or a list of any of those types.
1312         Strings will be compiled to re types. This returns the index into the
1313         pattern list. If the pattern was not a list this returns index 0 on a
1314         successful match. This may raise exceptions for EOF or TIMEOUT. To
1315         avoid the EOF or TIMEOUT exceptions add EOF or TIMEOUT to the pattern
1316         list. That will cause expect to match an EOF or TIMEOUT condition
1317         instead of raising an exception.
1318
1319         If you pass a list of patterns and more than one matches, the first
1320         match in the stream is chosen. If more than one pattern matches at that
1321         point, the leftmost in the pattern list is chosen. For example::
1322
1323             # the input is 'foobar'
1324             index = p.expect(['bar', 'foo', 'foobar'])
1325             # returns 1('foo') even though 'foobar' is a "better" match
1326
1327         Please note, however, that buffering can affect this behavior, since
1328         input arrives in unpredictable chunks. For example::
1329
1330             # the input is 'foobar'
1331             index = p.expect(['foobar', 'foo'])
1332             # returns 0('foobar') if all input is available at once,
1333             # but returs 1('foo') if parts of the final 'bar' arrive late
1334
1335         After a match is found the instance attributes 'before', 'after' and
1336         'match' will be set. You can see all the data read before the match in
1337         'before'. You can see the data that was matched in 'after'. The
1338         re.MatchObject used in the re match will be in 'match'. If an error
1339         occurred then 'before' will be set to all the data read so far and
1340         'after' and 'match' will be None.
1341
1342         If timeout is -1 then timeout will be set to the self.timeout value.
1343
1344         A list entry may be EOF or TIMEOUT instead of a string. This will
1345         catch these exceptions and return the index of the list entry instead
1346         of raising the exception. The attribute 'after' will be set to the
1347         exception type. The attribute 'match' will be None. This allows you to
1348         write code like this::
1349
1350                 index = p.expect(['good', 'bad', pexpect.EOF, pexpect.TIMEOUT])
1351                 if index == 0:
1352                     do_something()
1353                 elif index == 1:
1354                     do_something_else()
1355                 elif index == 2:
1356                     do_some_other_thing()
1357                 elif index == 3:
1358                     do_something_completely_different()
1359
1360         instead of code like this::
1361
1362                 try:
1363                     index = p.expect(['good', 'bad'])
1364                     if index == 0:
1365                         do_something()
1366                     elif index == 1:
1367                         do_something_else()
1368                 except EOF:
1369                     do_some_other_thing()
1370                 except TIMEOUT:
1371                     do_something_completely_different()
1372
1373         These two forms are equivalent. It all depends on what you want. You
1374         can also just expect the EOF if you are waiting for all output of a
1375         child to finish. For example::
1376
1377                 p = pexpect.spawn('/bin/ls')
1378                 p.expect(pexpect.EOF)
1379                 print p.before
1380
1381         If you are trying to optimize for speed then see expect_list().
1382         """
1383
1384         compiled_pattern_list = self.compile_pattern_list(pattern)
1385         return self.expect_list(compiled_pattern_list,
1386                 timeout, searchwindowsize)
1387
1388     def expect_list(self, pattern_list, timeout=-1, searchwindowsize=-1):
1389
1390         """This takes a list of compiled regular expressions and returns the
1391         index into the pattern_list that matched the child output. The list may
1392         also contain EOF or TIMEOUT(which are not compiled regular
1393         expressions). This method is similar to the expect() method except that
1394         expect_list() does not recompile the pattern list on every call. This
1395         may help if you are trying to optimize for speed, otherwise just use
1396         the expect() method.  This is called by expect(). If timeout==-1 then
1397         the self.timeout value is used. If searchwindowsize==-1 then the
1398         self.searchwindowsize value is used. """
1399
1400         return self.expect_loop(searcher_re(pattern_list),
1401                 timeout, searchwindowsize)
1402
1403     def expect_exact(self, pattern_list, timeout=-1, searchwindowsize=-1):
1404
1405         """This is similar to expect(), but uses plain string matching instead
1406         of compiled regular expressions in 'pattern_list'. The 'pattern_list'
1407         may be a string; a list or other sequence of strings; or TIMEOUT and
1408         EOF.
1409
1410         This call might be faster than expect() for two reasons: string
1411         searching is faster than RE matching and it is possible to limit the
1412         search to just the end of the input buffer.
1413
1414         This method is also useful when you don't want to have to worry about
1415         escaping regular expression characters that you want to match."""
1416
1417         if (type(pattern_list) in types.StringTypes or
1418             pattern_list in (TIMEOUT, EOF)):
1419             pattern_list = [pattern_list]
1420         return self.expect_loop(searcher_string(pattern_list),
1421                 timeout, searchwindowsize)
1422
1423     def expect_loop(self, searcher, timeout=-1, searchwindowsize=-1):
1424
1425         """This is the common loop used inside expect. The 'searcher' should be
1426         an instance of searcher_re or searcher_string, which describes how and
1427         what to search for in the input.
1428
1429         See expect() for other arguments, return value and exceptions. """
1430
1431         self.searcher = searcher
1432
1433         if timeout == -1:
1434             timeout = self.timeout
1435         if timeout is not None:
1436             end_time = time.time() + timeout
1437         if searchwindowsize == -1:
1438             searchwindowsize = self.searchwindowsize
1439
1440         try:
1441             incoming = self.buffer
1442             freshlen = len(incoming)
1443             while True:
1444                 # Keep reading until exception or return.
1445                 index = searcher.search(incoming, freshlen, searchwindowsize)
1446                 if index >= 0:
1447                     self.buffer = incoming[searcher.end:]
1448                     self.before = incoming[: searcher.start]
1449                     self.after = incoming[searcher.start: searcher.end]
1450                     self.match = searcher.match
1451                     self.match_index = index
1452                     return self.match_index
1453                 # No match at this point
1454                 if timeout < 0 and timeout is not None:
1455                     raise TIMEOUT('Timeout exceeded in expect_any().')
1456                 # Still have time left, so read more data
1457                 c = self.read_nonblocking(self.maxread, timeout)
1458                 freshlen = len(c)
1459                 time.sleep(0.0001)
1460                 incoming = incoming + c
1461                 if timeout is not None:
1462                     timeout = end_time - time.time()
1463         except EOF as e:
1464             self.buffer = ''
1465             self.before = incoming
1466             self.after = EOF
1467             index = searcher.eof_index
1468             if index >= 0:
1469                 self.match = EOF
1470                 self.match_index = index
1471                 return self.match_index
1472             else:
1473                 self.match = None
1474                 self.match_index = None
1475                 raise EOF(str(e) + '\n' + str(self))
1476         except TIMEOUT as e:
1477             self.buffer = incoming
1478             self.before = incoming
1479             self.after = TIMEOUT
1480             index = searcher.timeout_index
1481             if index >= 0:
1482                 self.match = TIMEOUT
1483                 self.match_index = index
1484                 return self.match_index
1485             else:
1486                 self.match = None
1487                 self.match_index = None
1488                 raise TIMEOUT(str(e) + '\n' + str(self))
1489         except:
1490             self.before = incoming
1491             self.after = None
1492             self.match = None
1493             self.match_index = None
1494             raise
1495
1496     def getwinsize(self):
1497
1498         """This returns the terminal window size of the child tty. The return
1499         value is a tuple of (rows, cols). """
1500
1501         TIOCGWINSZ = getattr(termios, 'TIOCGWINSZ', 1074295912)
1502         s = struct.pack('HHHH', 0, 0, 0, 0)
1503         x = fcntl.ioctl(self.fileno(), TIOCGWINSZ, s)
1504         return struct.unpack('HHHH', x)[0:2]
1505
1506     def setwinsize(self, rows, cols):
1507
1508         """This sets the terminal window size of the child tty. This will cause
1509         a SIGWINCH signal to be sent to the child. This does not change the
1510         physical window size. It changes the size reported to TTY-aware
1511         applications like vi or curses -- applications that respond to the
1512         SIGWINCH signal. """
1513
1514         # Check for buggy platforms. Some Python versions on some platforms
1515         # (notably OSF1 Alpha and RedHat 7.1) truncate the value for
1516         # termios.TIOCSWINSZ. It is not clear why this happens.
1517         # These platforms don't seem to handle the signed int very well;
1518         # yet other platforms like OpenBSD have a large negative value for
1519         # TIOCSWINSZ and they don't have a truncate problem.
1520         # Newer versions of Linux have totally different values for TIOCSWINSZ.
1521         # Note that this fix is a hack.
1522         TIOCSWINSZ = getattr(termios, 'TIOCSWINSZ', -2146929561)
1523         if TIOCSWINSZ == 2148037735:
1524             # Same bits, but with sign.
1525             TIOCSWINSZ = -2146929561
1526         # Note, assume ws_xpixel and ws_ypixel are zero.
1527         s = struct.pack('HHHH', rows, cols, 0, 0)
1528         fcntl.ioctl(self.fileno(), TIOCSWINSZ, s)
1529
1530     def interact(self, escape_character=chr(29),
1531             input_filter=None, output_filter=None):
1532
1533         """This gives control of the child process to the interactive user (the
1534         human at the keyboard). Keystrokes are sent to the child process, and
1535         the stdout and stderr output of the child process is printed. This
1536         simply echos the child stdout and child stderr to the real stdout and
1537         it echos the real stdin to the child stdin. When the user types the
1538         escape_character this method will stop. The default for
1539         escape_character is ^]. This should not be confused with ASCII 27 --
1540         the ESC character. ASCII 29 was chosen for historical merit because
1541         this is the character used by 'telnet' as the escape character. The
1542         escape_character will not be sent to the child process.
1543
1544         You may pass in optional input and output filter functions. These
1545         functions should take a string and return a string. The output_filter
1546         will be passed all the output from the child process. The input_filter
1547         will be passed all the keyboard input from the user. The input_filter
1548         is run BEFORE the check for the escape_character.
1549
1550         Note that if you change the window size of the parent the SIGWINCH
1551         signal will not be passed through to the child. If you want the child
1552         window size to change when the parent's window size changes then do
1553         something like the following example::
1554
1555             import pexpect, struct, fcntl, termios, signal, sys
1556             def sigwinch_passthrough (sig, data):
1557                 s = struct.pack("HHHH", 0, 0, 0, 0)
1558                 a = struct.unpack('hhhh', fcntl.ioctl(sys.stdout.fileno(),
1559                     termios.TIOCGWINSZ , s))
1560                 global p
1561                 p.setwinsize(a[0],a[1])
1562             # Note this 'p' global and used in sigwinch_passthrough.
1563             p = pexpect.spawn('/bin/bash')
1564             signal.signal(signal.SIGWINCH, sigwinch_passthrough)
1565             p.interact()
1566         """
1567
1568         # Flush the buffer.
1569         self.stdout.write(self.buffer)
1570         self.stdout.flush()
1571         self.buffer = ''
1572         mode = tty.tcgetattr(self.STDIN_FILENO)
1573         tty.setraw(self.STDIN_FILENO)
1574         try:
1575             self.__interact_copy(escape_character, input_filter, output_filter)
1576         finally:
1577             tty.tcsetattr(self.STDIN_FILENO, tty.TCSAFLUSH, mode)
1578
1579     def __interact_writen(self, fd, data):
1580
1581         """This is used by the interact() method.
1582         """
1583
1584         while data != '' and self.isalive():
1585             n = os.write(fd, data)
1586             data = data[n:]
1587
1588     def __interact_read(self, fd):
1589
1590         """This is used by the interact() method.
1591         """
1592
1593         return os.read(fd, 1000)
1594
1595     def __interact_copy(self, escape_character=None,
1596             input_filter=None, output_filter=None):
1597
1598         """This is used by the interact() method.
1599         """
1600
1601         while self.isalive():
1602             r, w, e = self.__select([self.child_fd, self.STDIN_FILENO], [], [])
1603             if self.child_fd in r:
1604                 data = self.__interact_read(self.child_fd)
1605                 if output_filter:
1606                     data = output_filter(data)
1607                 if self.logfile is not None:
1608                     self.logfile.write(data)
1609                     self.logfile.flush()
1610                 os.write(self.STDOUT_FILENO, data)
1611             if self.STDIN_FILENO in r:
1612                 data = self.__interact_read(self.STDIN_FILENO)
1613                 if input_filter:
1614                     data = input_filter(data)
1615                 i = data.rfind(escape_character)
1616                 if i != -1:
1617                     data = data[:i]
1618                     self.__interact_writen(self.child_fd, data)
1619                     break
1620                 self.__interact_writen(self.child_fd, data)
1621
1622     def __select(self, iwtd, owtd, ewtd, timeout=None):
1623
1624         """This is a wrapper around select.select() that ignores signals. If
1625         select.select raises a select.error exception and errno is an EINTR
1626         error then it is ignored. Mainly this is used to ignore sigwinch
1627         (terminal resize). """
1628
1629         # if select() is interrupted by a signal (errno==EINTR) then
1630         # we loop back and enter the select() again.
1631         if timeout is not None:
1632             end_time = time.time() + timeout
1633         while True:
1634             try:
1635                 return select.select(iwtd, owtd, ewtd, timeout)
1636             except select.error as e:
1637                 if e[0] == errno.EINTR:
1638                     # if we loop back we have to subtract the
1639                     # amount of time we already waited.
1640                     if timeout is not None:
1641                         timeout = end_time - time.time()
1642                         if timeout < 0:
1643                             return([], [], [])
1644                 else:
1645                     # something else caused the select.error, so
1646                     # this actually is an exception.
1647                     raise
1648
1649 ##############################################################################
1650 # The following methods are no longer supported or allowed.
1651
1652     def setmaxread(self, maxread):
1653
1654         """This method is no longer supported or allowed. I don't like getters
1655         and setters without a good reason. """
1656
1657         raise ExceptionPexpect('This method is no longer supported ' +
1658                 'or allowed. Just assign a value to the ' +
1659                 'maxread member variable.')
1660
1661     def setlog(self, fileobject):
1662
1663         """This method is no longer supported or allowed.
1664         """
1665
1666         raise ExceptionPexpect('This method is no longer supported ' +
1667                 'or allowed. Just assign a value to the logfile ' +
1668                 'member variable.')
1669
1670 ##############################################################################
1671 # End of spawn class
1672 ##############################################################################
1673
1674
1675 class searcher_string(object):
1676
1677     """This is a plain string search helper for the spawn.expect_any() method.
1678     This helper class is for speed. For more powerful regex patterns
1679     see the helper class, searcher_re.
1680
1681     Attributes:
1682
1683         eof_index     - index of EOF, or -1
1684         timeout_index - index of TIMEOUT, or -1
1685
1686     After a successful match by the search() method the following attributes
1687     are available:
1688
1689         start - index into the buffer, first byte of match
1690         end   - index into the buffer, first byte after match
1691         match - the matching string itself
1692
1693     """
1694
1695     def __init__(self, strings):
1696
1697         """This creates an instance of searcher_string. This argument 'strings'
1698         may be a list; a sequence of strings; or the EOF or TIMEOUT types. """
1699
1700         self.eof_index = -1
1701         self.timeout_index = -1
1702         self._strings = []
1703         for n, s in zip(list(range(len(strings))), strings):
1704             if s is EOF:
1705                 self.eof_index = n
1706                 continue
1707             if s is TIMEOUT:
1708                 self.timeout_index = n
1709                 continue
1710             self._strings.append((n, s))
1711
1712     def __str__(self):
1713
1714         """This returns a human-readable string that represents the state of
1715         the object."""
1716
1717         ss = [(ns[0], '    %d: "%s"' % ns) for ns in self._strings]
1718         ss.append((-1, 'searcher_string:'))
1719         if self.eof_index >= 0:
1720             ss.append((self.eof_index, '    %d: EOF' % self.eof_index))
1721         if self.timeout_index >= 0:
1722             ss.append((self.timeout_index,
1723                 '    %d: TIMEOUT' % self.timeout_index))
1724         ss.sort()
1725         ss = zip(*ss)[1]
1726         return '\n'.join(ss)
1727
1728     def search(self, buffer, freshlen, searchwindowsize=None):
1729
1730         """This searches 'buffer' for the first occurence of one of the search
1731         strings.  'freshlen' must indicate the number of bytes at the end of
1732         'buffer' which have not been searched before. It helps to avoid
1733         searching the same, possibly big, buffer over and over again.
1734
1735         See class spawn for the 'searchwindowsize' argument.
1736
1737         If there is a match this returns the index of that string, and sets
1738         'start', 'end' and 'match'. Otherwise, this returns -1. """
1739
1740         absurd_match = len(buffer)
1741         first_match = absurd_match
1742
1743         # 'freshlen' helps a lot here. Further optimizations could
1744         # possibly include:
1745         #
1746         # using something like the Boyer-Moore Fast String Searching
1747         # Algorithm; pre-compiling the search through a list of
1748         # strings into something that can scan the input once to
1749         # search for all N strings; realize that if we search for
1750         # ['bar', 'baz'] and the input is '...foo' we need not bother
1751         # rescanning until we've read three more bytes.
1752         #
1753         # Sadly, I don't know enough about this interesting topic. /grahn
1754
1755         for index, s in self._strings:
1756             if searchwindowsize is None:
1757                 # the match, if any, can only be in the fresh data,
1758                 # or at the very end of the old data
1759                 offset = -(freshlen + len(s))
1760             else:
1761                 # better obey searchwindowsize
1762                 offset = -searchwindowsize
1763             n = buffer.find(s, offset)
1764             if n >= 0 and n < first_match:
1765                 first_match = n
1766                 best_index, best_match = index, s
1767         if first_match == absurd_match:
1768             return -1
1769         self.match = best_match
1770         self.start = first_match
1771         self.end = self.start + len(self.match)
1772         return best_index
1773
1774
1775 class searcher_re(object):
1776
1777     """This is regular expression string search helper for the
1778     spawn.expect_any() method. This helper class is for powerful
1779     pattern matching. For speed, see the helper class, searcher_string.
1780
1781     Attributes:
1782
1783         eof_index     - index of EOF, or -1
1784         timeout_index - index of TIMEOUT, or -1
1785
1786     After a successful match by the search() method the following attributes
1787     are available:
1788
1789         start - index into the buffer, first byte of match
1790         end   - index into the buffer, first byte after match
1791         match - the re.match object returned by a succesful re.search
1792
1793     """
1794
1795     def __init__(self, patterns):
1796
1797         """This creates an instance that searches for 'patterns' Where
1798         'patterns' may be a list or other sequence of compiled regular
1799         expressions, or the EOF or TIMEOUT types."""
1800
1801         self.eof_index = -1
1802         self.timeout_index = -1
1803         self._searches = []
1804         for n, s in zip(list(range(len(patterns))), patterns):
1805             if s is EOF:
1806                 self.eof_index = n
1807                 continue
1808             if s is TIMEOUT:
1809                 self.timeout_index = n
1810                 continue
1811             self._searches.append((n, s))
1812
1813     def __str__(self):
1814
1815         """This returns a human-readable string that represents the state of
1816         the object."""
1817
1818         ss = [(n, '    %d: re.compile("%s")' %
1819             (n, str(s.pattern))) for n, s in self._searches]
1820         ss.append((-1, 'searcher_re:'))
1821         if self.eof_index >= 0:
1822             ss.append((self.eof_index, '    %d: EOF' % self.eof_index))
1823         if self.timeout_index >= 0:
1824             ss.append((self.timeout_index, '    %d: TIMEOUT' %
1825                 self.timeout_index))
1826         ss.sort()
1827         ss = zip(*ss)[1]
1828         return '\n'.join(ss)
1829
1830     def search(self, buffer, freshlen, searchwindowsize=None):
1831
1832         """This searches 'buffer' for the first occurence of one of the regular
1833         expressions. 'freshlen' must indicate the number of bytes at the end of
1834         'buffer' which have not been searched before.
1835
1836         See class spawn for the 'searchwindowsize' argument.
1837
1838         If there is a match this returns the index of that string, and sets
1839         'start', 'end' and 'match'. Otherwise, returns -1."""
1840
1841         absurd_match = len(buffer)
1842         first_match = absurd_match
1843         # 'freshlen' doesn't help here -- we cannot predict the
1844         # length of a match, and the re module provides no help.
1845         if searchwindowsize is None:
1846             searchstart = 0
1847         else:
1848             searchstart = max(0, len(buffer) - searchwindowsize)
1849         for index, s in self._searches:
1850             match = s.search(buffer, searchstart)
1851             if match is None:
1852                 continue
1853             n = match.start()
1854             if n < first_match:
1855                 first_match = n
1856                 the_match = match
1857                 best_index = index
1858         if first_match == absurd_match:
1859             return -1
1860         self.start = first_match
1861         self.match = the_match
1862         self.end = self.match.end()
1863         return best_index
1864
1865
1866 def which(filename):
1867
1868     """This takes a given filename; tries to find it in the environment path;
1869     then checks if it is executable. This returns the full path to the filename
1870     if found and executable. Otherwise this returns None."""
1871
1872     # Special case where filename contains an explicit path.
1873     if os.path.dirname(filename) != '':
1874         if os.access(filename, os.X_OK):
1875             return filename
1876     if 'PATH' not in os.environ or os.environ['PATH'] == '':
1877         p = os.defpath
1878     else:
1879         p = os.environ['PATH']
1880     pathlist = string.split(p, os.pathsep)
1881     for path in pathlist:
1882         ff = os.path.join(path, filename)
1883         if os.access(ff, os.X_OK):
1884             return ff
1885     return None
1886
1887
1888 def split_command_line(command_line):
1889
1890     """This splits a command line into a list of arguments. It splits arguments
1891     on spaces, but handles embedded quotes, doublequotes, and escaped
1892     characters. It's impossible to do this with a regular expression, so I
1893     wrote a little state machine to parse the command line. """
1894
1895     arg_list = []
1896     arg = ''
1897
1898     # Constants to name the states we can be in.
1899     state_basic = 0
1900     state_esc = 1
1901     state_singlequote = 2
1902     state_doublequote = 3
1903     # The state when consuming whitespace between commands.
1904     state_whitespace = 4
1905     state = state_basic
1906
1907     for c in command_line:
1908         if state == state_basic or state == state_whitespace:
1909             if c == '\\':
1910                 # Escape the next character
1911                 state = state_esc
1912             elif c == r"'":
1913                 # Handle single quote
1914                 state = state_singlequote
1915             elif c == r'"':
1916                 # Handle double quote
1917                 state = state_doublequote
1918             elif c.isspace():
1919                 # Add arg to arg_list if we aren't in the middle of whitespace.
1920                 if state == state_whitespace:
1921                     # Do nothing.
1922                     None
1923                 else:
1924                     arg_list.append(arg)
1925                     arg = ''
1926                     state = state_whitespace
1927             else:
1928                 arg = arg + c
1929                 state = state_basic
1930         elif state == state_esc:
1931             arg = arg + c
1932             state = state_basic
1933         elif state == state_singlequote:
1934             if c == r"'":
1935                 state = state_basic
1936             else:
1937                 arg = arg + c
1938         elif state == state_doublequote:
1939             if c == r'"':
1940                 state = state_basic
1941             else:
1942                 arg = arg + c
1943
1944     if arg != '':
1945         arg_list.append(arg)
1946     return arg_list
1947
1948 # vi:set sr et ts=4 sw=4 ft=python :