# subprocess - Subprocesses with accessible I/O streams # # For more information about this module, see PEP 324. # # Copyright (c) 2003-2005 by Peter Astrand # # Licensed to PSF under a Contributor Agreement. # See http://www.python.org/3.3/license for licensing details. r"""Subprocesses with accessible I/O streams This module allows you to spawn processes, connect to their input/output/error pipes, and obtain their return codes. For a complete description of this module see the Python documentation. Main API ======== run(...): Runs a command, waits for it to complete, then returns a CompletedProcess instance. Popen(...): A class for flexibly executing a command in a new process Constants --------- DEVNULL: Special value that indicates that os.devnull should be used PIPE: Special value that indicates a pipe should be created STDOUT: Special value that indicates that stderr should go to stdout Older API ========= call(...): Runs a command, waits for it to complete, then returns the return code. check_call(...): Same as call() but raises CalledProcessError() if return code is not 0 check_output(...): Same as check_call() but returns the contents of stdout instead of a return code """ import sys mswindows = (sys.platform == "win32") import os import errno import exceptions import types import time import traceback import gc import signal # Exception classes used by this module. class SubprocessError(Exception): pass class CalledProcessError(SubprocessError): """Raised when run() is called with check=True and the process returns a non-zero exit status. Attributes: cmd, returncode, stdout, stderr, output """ def __init__(self, returncode, cmd, output=None, stderr=None): self.returncode = returncode self.cmd = cmd self.output = output self.stderr = stderr super(CalledProcessError, self).__init__(returncode, cmd, output, stderr) def __str__(self): if self.returncode and self.returncode < 0: return "Command '%s' died with signal %d." % ( self.cmd, -self.returncode) else: return "Command '%s' returned non-zero exit status %d." % ( self.cmd, self.returncode) #@property def __stdout_getter(self): """Alias for output attribute, to match stderr""" return self.output #@stdout.setter # Required Python 2.6 def __stdout_setter(self, value): # There's no obvious reason to set this, but allow it anyway so # .stdout is a transparent alias for .output self.output = value stdout = property(__stdout_getter, __stdout_setter) # Python 2.4 class TimeoutExpired(SubprocessError): """This exception is raised when the timeout expires while waiting for a child process. Attributes: cmd, output, stdout, stderr, timeout """ def __init__(self, cmd, timeout, output=None, stderr=None): self.cmd = cmd self.timeout = timeout self.output = output self.stderr = stderr super(TimeoutExpired, self).__init__(cmd, timeout, output, stderr) def __str__(self): return ("Command '%s' timed out after %s seconds" % (self.cmd, self.timeout)) #@property def __stdout_getter(self): return self.output #@stdout.setter # Required Python 2.6 def __stdout_setter(self, value): # There's no obvious reason to set this, but allow it anyway so # .stdout is a transparent alias for .output self.output = value stdout = property(__stdout_getter, __stdout_setter) # Python 2.4 if mswindows: import threading import msvcrt import _subprocess class STARTUPINFO: dwFlags = 0 hStdInput = None hStdOutput = None hStdError = None wShowWindow = 0 class pywintypes: error = IOError else: import select _has_poll = hasattr(select, 'poll') import fcntl import pickle try: import _posixsubprocess32 as _posixsubprocess except ImportError: _posixsubprocess = None import warnings warnings.warn("The _posixsubprocess module is not being used. " "Child process reliability may suffer if your " "program uses threads.", RuntimeWarning) try: import threading except ImportError: import dummy_threading as threading # When select or poll has indicated that the file is writable, # we can write up to _PIPE_BUF bytes without risk of blocking. # POSIX defines PIPE_BUF as >= 512. _PIPE_BUF = getattr(select, 'PIPE_BUF', 512) _FD_CLOEXEC = getattr(fcntl, 'FD_CLOEXEC', 1) def _set_cloexec(fd, cloexec): old = fcntl.fcntl(fd, fcntl.F_GETFD) if cloexec: fcntl.fcntl(fd, fcntl.F_SETFD, old | _FD_CLOEXEC) else: fcntl.fcntl(fd, fcntl.F_SETFD, old & ~_FD_CLOEXEC) if _posixsubprocess: _create_pipe = _posixsubprocess.cloexec_pipe else: def _create_pipe(): fds = os.pipe() _set_cloexec(fds[0], True) _set_cloexec(fds[1], True) return fds __all__ = ["Popen", "PIPE", "STDOUT", "call", "check_call", "check_output", "CalledProcessError"] if mswindows: from _subprocess import (CREATE_NEW_CONSOLE, CREATE_NEW_PROCESS_GROUP, STD_INPUT_HANDLE, STD_OUTPUT_HANDLE, STD_ERROR_HANDLE, SW_HIDE, STARTF_USESTDHANDLES, STARTF_USESHOWWINDOW) # https://msdn.microsoft.com/en-us/library/windows/desktop/ms687032(v=vs.85).aspx # Note: In Python 3.3 this constant is found in the _winapi module. _WAIT_TIMEOUT = 0x102 __all__.extend(["CREATE_NEW_CONSOLE", "CREATE_NEW_PROCESS_GROUP", "STD_INPUT_HANDLE", "STD_OUTPUT_HANDLE", "STD_ERROR_HANDLE", "SW_HIDE", "STARTF_USESTDHANDLES", "STARTF_USESHOWWINDOW"]) try: MAXFD = os.sysconf("SC_OPEN_MAX") except: MAXFD = 256 # This lists holds Popen instances for which the underlying process had not # exited at the time its __del__ method got called: those processes are wait()ed # for synchronously from _cleanup() when a new Popen object is created, to avoid # zombie processes. _active = [] def _cleanup(): for inst in _active[:]: res = inst._internal_poll(_deadstate=sys.maxint) if res is not None: try: _active.remove(inst) except ValueError: # This can happen if two threads create a new Popen instance. # It's harmless that it was already removed, so ignore. pass PIPE = -1 STDOUT = -2 DEVNULL = -3 # This function is only used by multiprocessing, it is here so that people # can drop subprocess32 in as a replacement for the stdlib subprocess module. def _args_from_interpreter_flags(): """Return a list of command-line arguments reproducing the current settings in sys.flags and sys.warnoptions.""" flag_opt_map = { 'debug': 'd', # 'inspect': 'i', # 'interactive': 'i', 'optimize': 'O', 'dont_write_bytecode': 'B', 'no_user_site': 's', 'no_site': 'S', 'ignore_environment': 'E', 'verbose': 'v', 'bytes_warning': 'b', 'py3k_warning': '3', } args = [] for flag, opt in flag_opt_map.items(): v = getattr(sys.flags, flag) if v > 0: args.append('-' + opt * v) if getattr(sys.flags, 'hash_randomization') != 0: args.append('-R') for opt in sys.warnoptions: args.append('-W' + opt) return args def _eintr_retry_call(func, *args): while True: try: return func(*args) except (OSError, IOError), e: if e.errno == errno.EINTR: continue raise def _get_exec_path(env=None): """Returns the sequence of directories that will be searched for the named executable (similar to a shell) when launching a process. *env* must be an environment variable dict or None. If *env* is None, os.environ will be used. """ if env is None: env = os.environ return env.get('PATH', os.defpath).split(os.pathsep) if hasattr(os, 'get_exec_path'): _get_exec_path = os.get_exec_path def call(*popenargs, **kwargs): """Run command with arguments. Wait for command to complete or timeout, then return the returncode attribute. The arguments are the same as for the Popen constructor. Example: retcode = call(["ls", "-l"]) """ timeout = kwargs.pop('timeout', None) p = Popen(*popenargs, **kwargs) try: return p.wait(timeout=timeout) except TimeoutExpired: p.kill() p.wait() raise def check_call(*popenargs, **kwargs): """Run command with arguments. Wait for command to complete. If the exit code was zero then return, otherwise raise CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute. The arguments are the same as for the call function. Example: check_call(["ls", "-l"]) """ retcode = call(*popenargs, **kwargs) if retcode: cmd = kwargs.get("args") if cmd is None: cmd = popenargs[0] raise CalledProcessError(retcode, cmd) return 0 def check_output(*popenargs, **kwargs): r"""Run command with arguments and return its output as a byte string. If the exit code was non-zero it raises a CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute and output in the output attribute. The arguments are the same as for the Popen constructor. Example: >>> check_output(["ls", "-l", "/dev/null"]) 'crw-rw-rw- 1 root root 1, 3 Oct 18 2007 /dev/null\n' The stdout argument is not allowed as it is used internally. To capture standard error in the result, use stderr=STDOUT. >>> check_output(["/bin/sh", "-c", ... "ls -l non_existent_file ; exit 0"], ... stderr=STDOUT) 'ls: non_existent_file: No such file or directory\n' """ timeout = kwargs.pop('timeout', None) if 'stdout' in kwargs: raise ValueError('stdout argument not allowed, it will be overridden.') process = Popen(stdout=PIPE, *popenargs, **kwargs) try: output, unused_err = process.communicate(timeout=timeout) except TimeoutExpired: process.kill() output, unused_err = process.communicate() raise TimeoutExpired(process.args, timeout, output=output) retcode = process.poll() if retcode: raise CalledProcessError(retcode, process.args, output=output) return output class CompletedProcess(object): """A process that has finished running. This is returned by run(). Attributes: args: The list or str args passed to run(). returncode: The exit code of the process, negative for signals. stdout: The standard output (None if not captured). stderr: The standard error (None if not captured). """ def __init__(self, args, returncode, stdout=None, stderr=None): self.args = args self.returncode = returncode self.stdout = stdout self.stderr = stderr def __repr__(self): args = ['args={!r}'.format(self.args), 'returncode={!r}'.format(self.returncode)] if self.stdout is not None: args.append('stdout={!r}'.format(self.stdout)) if self.stderr is not None: args.append('stderr={!r}'.format(self.stderr)) return "{}({})".format(type(self).__name__, ', '.join(args)) def check_returncode(self): """Raise CalledProcessError if the exit code is non-zero.""" if self.returncode: raise CalledProcessError(self.returncode, self.args, self.stdout, self.stderr) def run(*popenargs, **kwargs): """Run command with arguments and return a CompletedProcess instance. The returned instance will have attributes args, returncode, stdout and stderr. By default, stdout and stderr are not captured, and those attributes will be None. Pass stdout=PIPE and/or stderr=PIPE in order to capture them. If check is True and the exit code was non-zero, it raises a CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute, and output & stderr attributes if those streams were captured. If timeout is given, and the process takes too long, a TimeoutExpired exception will be raised. There is an optional argument "input", allowing you to pass a string to the subprocess's stdin. If you use this argument you may not also use the Popen constructor's "stdin" argument, as it will be used internally. The other arguments are the same as for the Popen constructor. If universal_newlines=True is passed, the "input" argument must be a string and stdout/stderr in the returned object will be strings rather than bytes. """ input = kwargs.pop('input', None) timeout = kwargs.pop('timeout', None) check = kwargs.pop('check', False) if input is not None: if 'stdin' in kwargs: raise ValueError('stdin and input arguments may not both be used.') kwargs['stdin'] = PIPE process = Popen(*popenargs, **kwargs) try: process.__enter__() # No-Op really... illustrate "with in 2.4" try: stdout, stderr = process.communicate(input, timeout=timeout) except TimeoutExpired: process.kill() stdout, stderr = process.communicate() raise TimeoutExpired(process.args, timeout, output=stdout, stderr=stderr) except: process.kill() process.wait() raise retcode = process.poll() if check and retcode: raise CalledProcessError(retcode, process.args, output=stdout, stderr=stderr) finally: # None because our context manager __exit__ does not use them. process.__exit__(None, None, None) return CompletedProcess(process.args, retcode, stdout, stderr) def list2cmdline(seq): """ Translate a sequence of arguments into a command line string, using the same rules as the MS C runtime: 1) Arguments are delimited by white space, which is either a space or a tab. 2) A string surrounded by double quotation marks is interpreted as a single argument, regardless of white space contained within. A quoted string can be embedded in an argument. 3) A double quotation mark preceded by a backslash is interpreted as a literal double quotation mark. 4) Backslashes are interpreted literally, unless they immediately precede a double quotation mark. 5) If backslashes immediately precede a double quotation mark, every pair of backslashes is interpreted as a literal backslash. If the number of backslashes is odd, the last backslash escapes the next double quotation mark as described in rule 3. """ # See # http://msdn.microsoft.com/en-us/library/17w5ykft.aspx # or search http://msdn.microsoft.com for # "Parsing C++ Command-Line Arguments" result = [] needquote = False for arg in seq: bs_buf = [] # Add a space to separate this argument from the others if result: result.append(' ') needquote = (" " in arg) or ("\t" in arg) or not arg if needquote: result.append('"') for c in arg: if c == '\\': # Don't know if we need to double yet. bs_buf.append(c) elif c == '"': # Double backslashes. result.append('\\' * len(bs_buf)*2) bs_buf = [] result.append('\\"') else: # Normal char if bs_buf: result.extend(bs_buf) bs_buf = [] result.append(c) # Add remaining backslashes, if any. if bs_buf: result.extend(bs_buf) if needquote: result.extend(bs_buf) result.append('"') return ''.join(result) _PLATFORM_DEFAULT_CLOSE_FDS = object() class Popen(object): def __init__(self, args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=_PLATFORM_DEFAULT_CLOSE_FDS, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0, restore_signals=True, start_new_session=False, pass_fds=()): """Create new Popen instance.""" _cleanup() # Held while anything is calling waitpid before returncode has been # updated to prevent clobbering returncode if wait() or poll() are # called from multiple threads at once. After acquiring the lock, # code must re-check self.returncode to see if another thread just # finished a waitpid() call. self._waitpid_lock = threading.Lock() self._child_created = False self._input = None self._communication_started = False if not isinstance(bufsize, (int, long)): raise TypeError("bufsize must be an integer") if mswindows: if preexec_fn is not None: raise ValueError("preexec_fn is not supported on Windows " "platforms") any_stdio_set = (stdin is not None or stdout is not None or stderr is not None) if close_fds is _PLATFORM_DEFAULT_CLOSE_FDS: if any_stdio_set: close_fds = False else: close_fds = True elif close_fds and any_stdio_set: raise ValueError( "close_fds is not supported on Windows platforms" " if you redirect stdin/stdout/stderr") else: # POSIX if close_fds is _PLATFORM_DEFAULT_CLOSE_FDS: close_fds = True if pass_fds and not close_fds: import warnings warnings.warn("pass_fds overriding close_fds.", RuntimeWarning) close_fds = True if startupinfo is not None: raise ValueError("startupinfo is only supported on Windows " "platforms") if creationflags != 0: raise ValueError("creationflags is only supported on Windows " "platforms") self.args = args self.stdin = None self.stdout = None self.stderr = None self.pid = None self.returncode = None self.universal_newlines = universal_newlines # Input and output objects. The general principle is like # this: # # Parent Child # ------ ----- # p2cwrite ---stdin---> p2cread # c2pread <--stdout--- c2pwrite # errread <--stderr--- errwrite # # On POSIX, the child objects are file descriptors. On # Windows, these are Windows file handles. The parent objects # are file descriptors on both platforms. The parent objects # are -1 when not using PIPEs. The child objects are -1 # when not redirecting. (p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite) = self._get_handles(stdin, stdout, stderr) if mswindows: if p2cwrite != -1: p2cwrite = msvcrt.open_osfhandle(p2cwrite.Detach(), 0) if c2pread != -1: c2pread = msvcrt.open_osfhandle(c2pread.Detach(), 0) if errread != -1: errread = msvcrt.open_osfhandle(errread.Detach(), 0) if p2cwrite != -1: self.stdin = os.fdopen(p2cwrite, 'wb', bufsize) if c2pread != -1: if universal_newlines: self.stdout = os.fdopen(c2pread, 'rU', bufsize) else: self.stdout = os.fdopen(c2pread, 'rb', bufsize) if errread != -1: if universal_newlines: self.stderr = os.fdopen(errread, 'rU', bufsize) else: self.stderr = os.fdopen(errread, 'rb', bufsize) self._closed_child_pipe_fds = False exception_cleanup_needed = False try: try: self._execute_child(args, executable, preexec_fn, close_fds, pass_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, restore_signals, start_new_session) except: # The cleanup is performed within the finally block rather # than simply within this except block before the raise so # that any exceptions raised and handled within it do not # clobber the exception context we want to propagate upwards. # This is only necessary in Python 2. exception_cleanup_needed = True raise finally: if exception_cleanup_needed: for f in filter(None, (self.stdin, self.stdout, self.stderr)): try: f.close() except EnvironmentError: pass # Ignore EBADF or other errors if not self._closed_child_pipe_fds: to_close = [] if stdin == PIPE: to_close.append(p2cread) if stdout == PIPE: to_close.append(c2pwrite) if stderr == PIPE: to_close.append(errwrite) if hasattr(self, '_devnull'): to_close.append(self._devnull) for fd in to_close: try: os.close(fd) except EnvironmentError: pass def __enter__(self): return self def __exit__(self, type, value, traceback): if self.stdout: self.stdout.close() if self.stderr: self.stderr.close() if self.stdin: self.stdin.close() # Wait for the process to terminate, to avoid zombies. self.wait() def _translate_newlines(self, data): data = data.replace("\r\n", "\n") data = data.replace("\r", "\n") return data def __del__(self, _maxint=sys.maxint, _active=_active): # If __init__ hasn't had a chance to execute (e.g. if it # was passed an undeclared keyword argument), we don't # have a _child_created attribute at all. if not getattr(self, '_child_created', False): # We didn't get to successfully create a child process. return # In case the child hasn't been waited on, check if it's done. self._internal_poll(_deadstate=_maxint) if self.returncode is None and _active is not None: # Child is still running, keep us alive until we can wait on it. _active.append(self) def _get_devnull(self): if not hasattr(self, '_devnull'): self._devnull = os.open(os.devnull, os.O_RDWR) return self._devnull def _stdin_write(self, input): if input: try: self.stdin.write(input) except EnvironmentError as e: if e.errno == errno.EPIPE: # communicate() must ignore broken pipe error pass elif e.errno == errno.EINVAL : # bpo-19612, bpo-30418: On Windows, stdin.write() fails # with EINVAL if the child process exited or if the child # process is still running but closed the pipe. pass else: raise try: self.stdin.close() except EnvironmentError as e: if e.errno in (errno.EPIPE, errno.EINVAL): pass else: raise def communicate(self, input=None, timeout=None): """Interact with process: Send data to stdin. Read data from stdout and stderr, until end-of-file is reached. Wait for process to terminate. The optional input argument should be a string to be sent to the child process, or None, if no data should be sent to the child. communicate() returns a tuple (stdout, stderr).""" if self._communication_started and input: raise ValueError("Cannot send input after starting communication") if timeout is not None: endtime = time.time() + timeout else: endtime = None # Optimization: If we are not worried about timeouts, we haven't # started communicating, and we have one or zero pipes, using select() # or threads is unnecessary. if (endtime is None and not self._communication_started and [self.stdin, self.stdout, self.stderr].count(None) >= 2): stdout = None stderr = None if self.stdin: self._stdin_write(input) elif self.stdout: stdout = _eintr_retry_call(self.stdout.read) self.stdout.close() elif self.stderr: stderr = _eintr_retry_call(self.stderr.read) self.stderr.close() self.wait() return (stdout, stderr) try: stdout, stderr = self._communicate(input, endtime, timeout) finally: self._communication_started = True sts = self.wait(timeout=self._remaining_time(endtime)) return (stdout, stderr) def poll(self): return self._internal_poll() def _remaining_time(self, endtime): """Convenience for _communicate when computing timeouts.""" if endtime is None: return None else: return endtime - time.time() def _check_timeout(self, endtime, orig_timeout): """Convenience for checking if a timeout has expired.""" if endtime is None: return if time.time() > endtime: raise TimeoutExpired(self.args, orig_timeout) if mswindows: # # Windows methods # def _get_handles(self, stdin, stdout, stderr): """Construct and return tuple with IO objects: p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite """ if stdin is None and stdout is None and stderr is None: return (-1, -1, -1, -1, -1, -1) p2cread, p2cwrite = -1, -1 c2pread, c2pwrite = -1, -1 errread, errwrite = -1, -1 if stdin is None: p2cread = _subprocess.GetStdHandle(_subprocess.STD_INPUT_HANDLE) if p2cread is None: p2cread, _ = _subprocess.CreatePipe(None, 0) elif stdin == PIPE: p2cread, p2cwrite = _subprocess.CreatePipe(None, 0) elif stdin == DEVNULL: p2cread = msvcrt.get_osfhandle(self._get_devnull()) elif isinstance(stdin, int): p2cread = msvcrt.get_osfhandle(stdin) else: # Assuming file-like object p2cread = msvcrt.get_osfhandle(stdin.fileno()) p2cread = self._make_inheritable(p2cread) if stdout is None: c2pwrite = _subprocess.GetStdHandle(_subprocess.STD_OUTPUT_HANDLE) if c2pwrite is None: _, c2pwrite = _subprocess.CreatePipe(None, 0) elif stdout == PIPE: c2pread, c2pwrite = _subprocess.CreatePipe(None, 0) elif stdout == DEVNULL: c2pwrite = msvcrt.get_osfhandle(self._get_devnull()) elif isinstance(stdout, int): c2pwrite = msvcrt.get_osfhandle(stdout) else: # Assuming file-like object c2pwrite = msvcrt.get_osfhandle(stdout.fileno()) c2pwrite = self._make_inheritable(c2pwrite) if stderr is None: errwrite = _subprocess.GetStdHandle(_subprocess.STD_ERROR_HANDLE) if errwrite is None: _, errwrite = _subprocess.CreatePipe(None, 0) elif stderr == PIPE: errread, errwrite = _subprocess.CreatePipe(None, 0) elif stderr == STDOUT: errwrite = c2pwrite elif stderr == DEVNULL: errwrite = msvcrt.get_osfhandle(self._get_devnull()) elif isinstance(stderr, int): errwrite = msvcrt.get_osfhandle(stderr) else: # Assuming file-like object errwrite = msvcrt.get_osfhandle(stderr.fileno()) errwrite = self._make_inheritable(errwrite) return (p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite) def _make_inheritable(self, handle): """Return a duplicate of handle, which is inheritable""" return _subprocess.DuplicateHandle(_subprocess.GetCurrentProcess(), handle, _subprocess.GetCurrentProcess(), 0, 1, _subprocess.DUPLICATE_SAME_ACCESS) def _find_w9xpopen(self): """Find and return absolut path to w9xpopen.exe""" w9xpopen = os.path.join( os.path.dirname(_subprocess.GetModuleFileName(0)), "w9xpopen.exe") if not os.path.exists(w9xpopen): # Eeek - file-not-found - possibly an embedding # situation - see if we can locate it in sys.exec_prefix w9xpopen = os.path.join(os.path.dirname(sys.exec_prefix), "w9xpopen.exe") if not os.path.exists(w9xpopen): raise RuntimeError("Cannot locate w9xpopen.exe, which is " "needed for Popen to work with your " "shell or platform.") return w9xpopen def _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, unused_restore_signals, unused_start_new_session): """Execute program (MS Windows version)""" assert not pass_fds, "pass_fds not supported on Windows." if not isinstance(args, types.StringTypes): args = list2cmdline(args) # Process startup details if startupinfo is None: startupinfo = STARTUPINFO() if -1 not in (p2cread, c2pwrite, errwrite): startupinfo.dwFlags |= _subprocess.STARTF_USESTDHANDLES startupinfo.hStdInput = p2cread startupinfo.hStdOutput = c2pwrite startupinfo.hStdError = errwrite if shell: startupinfo.dwFlags |= _subprocess.STARTF_USESHOWWINDOW startupinfo.wShowWindow = _subprocess.SW_HIDE comspec = os.environ.get("COMSPEC", "cmd.exe") args = comspec + " /c " + '"%s"' % args if (_subprocess.GetVersion() >= 0x80000000L or os.path.basename(comspec).lower() == "command.com"): # Win9x, or using command.com on NT. We need to # use the w9xpopen intermediate program. For more # information, see KB Q150956 # (http://web.archive.org/web/20011105084002/http://support.microsoft.com/support/kb/articles/Q150/9/56.asp) w9xpopen = self._find_w9xpopen() args = '"%s" %s' % (w9xpopen, args) # Not passing CREATE_NEW_CONSOLE has been known to # cause random failures on win9x. Specifically a # dialog: "Your program accessed mem currently in # use at xxx" and a hopeful warning about the # stability of your system. Cost is Ctrl+C wont # kill children. creationflags |= _subprocess.CREATE_NEW_CONSOLE # Start the process try: try: hp, ht, pid, tid = _subprocess.CreateProcess(executable, args, # no special security None, None, int(not close_fds), creationflags, env, cwd, startupinfo) except pywintypes.error, e: # Translate pywintypes.error to WindowsError, which is # a subclass of OSError. FIXME: We should really # translate errno using _sys_errlist (or similar), but # how can this be done from Python? raise WindowsError(*e.args) finally: # Child is launched. Close the parent's copy of those pipe # handles that only the child should have open. You need # to make sure that no handles to the write end of the # output pipe are maintained in this process or else the # pipe will not close when the child process exits and the # ReadFile will hang. if p2cread != -1: p2cread.Close() if c2pwrite != -1: c2pwrite.Close() if errwrite != -1: errwrite.Close() if hasattr(self, '_devnull'): os.close(self._devnull) # Retain the process handle, but close the thread handle self._child_created = True self._handle = hp self.pid = pid ht.Close() def _internal_poll(self, _deadstate=None, _WaitForSingleObject=_subprocess.WaitForSingleObject, _WAIT_OBJECT_0=_subprocess.WAIT_OBJECT_0, _GetExitCodeProcess=_subprocess.GetExitCodeProcess): """Check if child process has terminated. Returns returncode attribute. This method is called by __del__, so it can only refer to objects in its local scope. """ if self.returncode is None: if _WaitForSingleObject(self._handle, 0) == _WAIT_OBJECT_0: self.returncode = _GetExitCodeProcess(self._handle) return self.returncode def wait(self, timeout=None, endtime=None): """Wait for child process to terminate. Returns returncode attribute.""" if endtime is not None: timeout_millis = self._remaining_time(endtime) if timeout is None: timeout_millis = _subprocess.INFINITE else: timeout_millis = int(timeout * 1000) if self.returncode is None: result = _subprocess.WaitForSingleObject(self._handle, timeout_millis) if result == _WAIT_TIMEOUT: raise TimeoutExpired(self.args, timeout) self.returncode = _subprocess.GetExitCodeProcess(self._handle) return self.returncode def _readerthread(self, fh, buffer): buffer.append(fh.read()) fh.close() def _communicate(self, input, endtime, orig_timeout): # Start reader threads feeding into a list hanging off of this # object, unless they've already been started. if self.stdout and not hasattr(self, "_stdout_buff"): self._stdout_buff = [] self.stdout_thread = \ threading.Thread(target=self._readerthread, args=(self.stdout, self._stdout_buff)) self.stdout_thread.daemon = True self.stdout_thread.start() if self.stderr and not hasattr(self, "_stderr_buff"): self._stderr_buff = [] self.stderr_thread = \ threading.Thread(target=self._readerthread, args=(self.stderr, self._stderr_buff)) self.stderr_thread.daemon = True self.stderr_thread.start() if self.stdin: self._stdin_write(input) # Wait for the reader threads, or time out. If we time out, the # threads remain reading and the fds left open in case the user # calls communicate again. if self.stdout is not None: self.stdout_thread.join(self._remaining_time(endtime)) if self.stdout_thread.isAlive(): raise TimeoutExpired(self.args, orig_timeout) if self.stderr is not None: self.stderr_thread.join(self._remaining_time(endtime)) if self.stderr_thread.isAlive(): raise TimeoutExpired(self.args, orig_timeout) # Collect the output from and close both pipes, now that we know # both have been read successfully. stdout = None stderr = None if self.stdout: stdout = self._stdout_buff self.stdout.close() if self.stderr: stderr = self._stderr_buff self.stderr.close() # All data exchanged. Translate lists into strings. if stdout is not None: stdout = stdout[0] if stderr is not None: stderr = stderr[0] # Translate newlines, if requested. We cannot let the file # object do the translation: It is based on stdio, which is # impossible to combine with select (unless forcing no # buffering). if self.universal_newlines and hasattr(file, 'newlines'): if stdout: stdout = self._translate_newlines(stdout) if stderr: stderr = self._translate_newlines(stderr) return (stdout, stderr) def send_signal(self, sig): """Send a signal to the process.""" # Don't signal a process that we know has already died. if self.returncode is not None: return if sig == signal.SIGTERM: self.terminate() elif sig == signal.CTRL_C_EVENT: os.kill(self.pid, signal.CTRL_C_EVENT) elif sig == signal.CTRL_BREAK_EVENT: os.kill(self.pid, signal.CTRL_BREAK_EVENT) else: raise ValueError("Unsupported signal: %s" % sig) def terminate(self): """Terminates the process.""" # Don't terminate a process that we know has already died. if self.returncode is not None: return _subprocess.TerminateProcess(self._handle, 1) kill = terminate else: # # POSIX methods # def _get_handles(self, stdin, stdout, stderr): """Construct and return tuple with IO objects: p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite """ p2cread, p2cwrite = -1, -1 c2pread, c2pwrite = -1, -1 errread, errwrite = -1, -1 if stdin is None: pass elif stdin == PIPE: p2cread, p2cwrite = _create_pipe() elif stdin == DEVNULL: p2cread = self._get_devnull() elif isinstance(stdin, int): p2cread = stdin else: # Assuming file-like object p2cread = stdin.fileno() if stdout is None: pass elif stdout == PIPE: c2pread, c2pwrite = _create_pipe() elif stdout == DEVNULL: c2pwrite = self._get_devnull() elif isinstance(stdout, int): c2pwrite = stdout else: # Assuming file-like object c2pwrite = stdout.fileno() if stderr is None: pass elif stderr == PIPE: errread, errwrite = _create_pipe() elif stderr == STDOUT: if c2pwrite != -1: errwrite = c2pwrite else: # child's stdout is not set, use parent's stdout errwrite = sys.__stdout__.fileno() elif stderr == DEVNULL: errwrite = self._get_devnull() elif isinstance(stderr, int): errwrite = stderr else: # Assuming file-like object errwrite = stderr.fileno() return (p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite) if hasattr(os, 'closerange'): # Introduced in 2.6 @staticmethod def _closerange(fd_low, fd_high): os.closerange(fd_low, fd_high) else: @staticmethod def _closerange(fd_low, fd_high): for fd in xrange(fd_low, fd_high): while True: try: os.close(fd) except (OSError, IOError), e: if e.errno == errno.EINTR: continue break def _close_fds(self, but): self._closerange(3, but) self._closerange(but + 1, MAXFD) def _close_all_but_a_sorted_few_fds(self, fds_to_keep): # precondition: fds_to_keep must be sorted and unique start_fd = 3 for fd in fds_to_keep: if fd >= start_fd: self._closerange(start_fd, fd) start_fd = fd + 1 if start_fd <= MAXFD: self._closerange(start_fd, MAXFD) def _execute_child(self, args, executable, preexec_fn, close_fds, pass_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, restore_signals, start_new_session): """Execute program (POSIX version)""" if isinstance(args, types.StringTypes): args = [args] else: args = list(args) if shell: args = ["/bin/sh", "-c"] + args if executable: args[0] = executable if executable is None: executable = args[0] orig_executable = executable # For transferring possible exec failure from child to parent. # Data format: "exception name:hex errno:description" # Pickle is not used; it is complex and involves memory allocation. errpipe_read, errpipe_write = _create_pipe() try: try: if _posixsubprocess: fs_encoding = sys.getfilesystemencoding() def fs_encode(s): """Encode s for use in the env, fs or cmdline.""" if isinstance(s, str): return s else: return s.encode(fs_encoding, 'strict') # We must avoid complex work that could involve # malloc or free in the child process to avoid # potential deadlocks, thus we do all this here. # and pass it to fork_exec() if env is not None: env_list = [fs_encode(k) + '=' + fs_encode(v) for k, v in env.items()] else: env_list = None # Use execv instead of execve. if os.path.dirname(executable): executable_list = (fs_encode(executable),) else: # This matches the behavior of os._execvpe(). path_list = _get_exec_path(env) executable_list = (os.path.join(dir, executable) for dir in path_list) executable_list = tuple(fs_encode(exe) for exe in executable_list) fds_to_keep = set(pass_fds) fds_to_keep.add(errpipe_write) self.pid = _posixsubprocess.fork_exec( args, executable_list, close_fds, sorted(fds_to_keep), cwd, env_list, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite, errpipe_read, errpipe_write, restore_signals, start_new_session, preexec_fn) self._child_created = True else: # Pure Python implementation: It is not thread safe. # This implementation may deadlock in the child if your # parent process has any other threads running. gc_was_enabled = gc.isenabled() # Disable gc to avoid bug where gc -> file_dealloc -> # write to stderr -> hang. See issue1336 gc.disable() try: self.pid = os.fork() except: if gc_was_enabled: gc.enable() raise self._child_created = True if self.pid == 0: # Child reached_preexec = False try: # Close parent's pipe ends if p2cwrite != -1: os.close(p2cwrite) if c2pread != -1: os.close(c2pread) if errread != -1: os.close(errread) os.close(errpipe_read) # When duping fds, if there arises a situation # where one of the fds is either 0, 1 or 2, it # is possible that it is overwritten (#12607). if c2pwrite == 0: c2pwrite = os.dup(c2pwrite) if errwrite == 0 or errwrite == 1: errwrite = os.dup(errwrite) # Dup fds for child def _dup2(a, b): # dup2() removes the CLOEXEC flag but # we must do it ourselves if dup2() # would be a no-op (issue #10806). if a == b: _set_cloexec(a, False) elif a != -1: os.dup2(a, b) _dup2(p2cread, 0) _dup2(c2pwrite, 1) _dup2(errwrite, 2) # Close pipe fds. Make sure we don't close the # same fd more than once, or standard fds. closed = set() for fd in [p2cread, c2pwrite, errwrite]: if fd > 2 and fd not in closed: os.close(fd) closed.add(fd) if cwd is not None: os.chdir(cwd) # This is a copy of Python/pythonrun.c # _Py_RestoreSignals(). If that were exposed # as a sys._py_restoresignals func it would be # better.. but this pure python implementation # isn't likely to be used much anymore. if restore_signals: signals = ('SIGPIPE', 'SIGXFZ', 'SIGXFSZ') for sig in signals: if hasattr(signal, sig): signal.signal(getattr(signal, sig), signal.SIG_DFL) if start_new_session and hasattr(os, 'setsid'): os.setsid() reached_preexec = True if preexec_fn: preexec_fn() # Close all other fds, if asked for - after # preexec_fn(), which may open FDs. if close_fds: if pass_fds: fds_to_keep = set(pass_fds) fds_to_keep.add(errpipe_write) self._close_all_but_a_sorted_few_fds( sorted(fds_to_keep)) else: self._close_fds(but=errpipe_write) if env is None: os.execvp(executable, args) else: os.execvpe(executable, args, env) except: try: exc_type, exc_value = sys.exc_info()[:2] if isinstance(exc_value, OSError): errno_num = exc_value.errno else: errno_num = 0 if not reached_preexec: exc_value = "noexec" message = '%s:%x:%s' % (exc_type.__name__, errno_num, exc_value) os.write(errpipe_write, message) except Exception: # We MUST not allow anything odd happening # above to prevent us from exiting below. pass # This exitcode won't be reported to applications # so it really doesn't matter what we return. os._exit(255) # Parent if gc_was_enabled: gc.enable() finally: # be sure the FD is closed no matter what os.close(errpipe_write) # A pair of non -1s means we created both fds and are # responsible for closing them. # self._devnull is not always defined. devnull_fd = getattr(self, '_devnull', None) if p2cread != -1 and p2cwrite != -1 and p2cread != devnull_fd: os.close(p2cread) if c2pwrite != -1 and c2pread != -1 and c2pwrite != devnull_fd: os.close(c2pwrite) if errwrite != -1 and errread != -1 and errwrite != devnull_fd: os.close(errwrite) if devnull_fd is not None: os.close(devnull_fd) # Prevent a double close of these fds from __init__ on error. self._closed_child_pipe_fds = True # Wait for exec to fail or succeed; possibly raising exception # exception (limited in size) errpipe_data = '' while True: part = _eintr_retry_call(os.read, errpipe_read, 50000) errpipe_data += part if not part or len(errpipe_data) > 50000: break finally: # be sure the FD is closed no matter what os.close(errpipe_read) if errpipe_data != "": try: _eintr_retry_call(os.waitpid, self.pid, 0) except OSError, e: if e.errno != errno.ECHILD: raise try: exception_name, hex_errno, err_msg = ( errpipe_data.split(':', 2)) except ValueError: exception_name = 'RuntimeError' hex_errno = '0' err_msg = ('Bad exception data from child: ' + repr(errpipe_data)) child_exception_type = getattr( exceptions, exception_name, RuntimeError) if issubclass(child_exception_type, OSError) and hex_errno: errno_num = int(hex_errno, 16) child_exec_never_called = (err_msg == "noexec") if child_exec_never_called: err_msg = "" if errno_num != 0: err_msg = os.strerror(errno_num) if errno_num == errno.ENOENT: if child_exec_never_called: # The error must be from chdir(cwd). err_msg += ': ' + repr(cwd) else: err_msg += ': ' + repr(orig_executable) raise child_exception_type(errno_num, err_msg) try: exception = child_exception_type(err_msg) except Exception: exception = RuntimeError( 'Could not re-raise %r exception from the' ' child with error message %r' % (child_exception_type, err_msg)) raise exception def _handle_exitstatus(self, sts, _WIFSIGNALED=os.WIFSIGNALED, _WTERMSIG=os.WTERMSIG, _WIFEXITED=os.WIFEXITED, _WEXITSTATUS=os.WEXITSTATUS, _WIFSTOPPED=os.WIFSTOPPED, _WSTOPSIG=os.WSTOPSIG): """All callers to this function MUST hold self._waitpid_lock.""" # This method is called (indirectly) by __del__, so it cannot # refer to anything outside of its local scope.""" if _WIFSIGNALED(sts): self.returncode = -_WTERMSIG(sts) elif _WIFEXITED(sts): self.returncode = _WEXITSTATUS(sts) elif _WIFSTOPPED(sts): self.returncode = -_WSTOPSIG(sts) else: # Should never happen raise RuntimeError("Unknown child exit status!") def _internal_poll(self, _deadstate=None, _waitpid=os.waitpid, _WNOHANG=os.WNOHANG, _os_error=os.error, _ECHILD=errno.ECHILD): """Check if child process has terminated. Returns returncode attribute. This method is called by __del__, so it cannot reference anything outside of the local scope (nor can any methods it calls). """ if self.returncode is None: if not self._waitpid_lock.acquire(False): # Something else is busy calling waitpid. Don't allow two # at once. We know nothing yet. return None try: try: if self.returncode is not None: return self.returncode # Another thread waited. pid, sts = _waitpid(self.pid, _WNOHANG) if pid == self.pid: self._handle_exitstatus(sts) except _os_error, e: if _deadstate is not None: self.returncode = _deadstate elif e.errno == _ECHILD: # This happens if SIGCLD is set to be ignored or # waiting for child processes has otherwise been # disabled for our process. This child is dead, we # can't get the status. # http://bugs.python.org/issue15756 self.returncode = 0 finally: self._waitpid_lock.release() return self.returncode def _try_wait(self, wait_flags): """All callers to this function MUST hold self._waitpid_lock.""" try: (pid, sts) = _eintr_retry_call(os.waitpid, self.pid, wait_flags) except OSError, e: if e.errno != errno.ECHILD: raise # This happens if SIGCLD is set to be ignored or waiting # for child processes has otherwise been disabled for our # process. This child is dead, we can't get the status. pid = self.pid sts = 0 return (pid, sts) def wait(self, timeout=None, endtime=None): """Wait for child process to terminate. Returns returncode attribute.""" if self.returncode is not None: return self.returncode # endtime is preferred to timeout. timeout is only used for # printing. if endtime is not None or timeout is not None: if endtime is None: endtime = time.time() + timeout elif timeout is None: timeout = self._remaining_time(endtime) if endtime is not None: # Enter a busy loop if we have a timeout. This busy loop was # cribbed from Lib/threading.py in Thread.wait() at r71065. delay = 0.0005 # 500 us -> initial delay of 1 ms while True: if self._waitpid_lock.acquire(False): try: if self.returncode is not None: break # Another thread waited. (pid, sts) = self._try_wait(os.WNOHANG) assert pid == self.pid or pid == 0 if pid == self.pid: self._handle_exitstatus(sts) break finally: self._waitpid_lock.release() remaining = self._remaining_time(endtime) if remaining <= 0: raise TimeoutExpired(self.args, timeout) delay = min(delay * 2, remaining, .05) time.sleep(delay) else: while self.returncode is None: self._waitpid_lock.acquire() try: if self.returncode is not None: break # Another thread waited. (pid, sts) = self._try_wait(0) # Check the pid and loop as waitpid has been known to # return 0 even without WNOHANG in odd situations. # http://bugs.python.org/issue14396. if pid == self.pid: self._handle_exitstatus(sts) finally: self._waitpid_lock.release() return self.returncode def _communicate(self, input, endtime, orig_timeout): if self.stdin and not self._communication_started: # Flush stdio buffer. This might block, if the user has # been writing to .stdin in an uncontrolled fashion. self.stdin.flush() if not input: self.stdin.close() if _has_poll: stdout, stderr = self._communicate_with_poll(input, endtime, orig_timeout) else: stdout, stderr = self._communicate_with_select(input, endtime, orig_timeout) self.wait(timeout=self._remaining_time(endtime)) # All data exchanged. Translate lists into strings. if stdout is not None: stdout = ''.join(stdout) if stderr is not None: stderr = ''.join(stderr) # Translate newlines, if requested. We cannot let the file # object do the translation: It is based on stdio, which is # impossible to combine with select (unless forcing no # buffering). if self.universal_newlines and hasattr(file, 'newlines'): if stdout: stdout = self._translate_newlines(stdout) if stderr: stderr = self._translate_newlines(stderr) return (stdout, stderr) def _communicate_with_poll(self, input, endtime, orig_timeout): stdout = None # Return stderr = None # Return if not self._communication_started: self._fd2file = {} poller = select.poll() def register_and_append(file_obj, eventmask): poller.register(file_obj.fileno(), eventmask) self._fd2file[file_obj.fileno()] = file_obj def close_unregister_and_remove(fd): poller.unregister(fd) self._fd2file[fd].close() self._fd2file.pop(fd) if self.stdin and input: register_and_append(self.stdin, select.POLLOUT) # Only create this mapping if we haven't already. if not self._communication_started: self._fd2output = {} if self.stdout: self._fd2output[self.stdout.fileno()] = [] if self.stderr: self._fd2output[self.stderr.fileno()] = [] select_POLLIN_POLLPRI = select.POLLIN | select.POLLPRI if self.stdout: register_and_append(self.stdout, select_POLLIN_POLLPRI) stdout = self._fd2output[self.stdout.fileno()] if self.stderr: register_and_append(self.stderr, select_POLLIN_POLLPRI) stderr = self._fd2output[self.stderr.fileno()] # Save the input here so that if we time out while communicating, # we can continue sending input if we retry. if self.stdin and self._input is None: self._input_offset = 0 self._input = input if self.universal_newlines and isinstance(self._input, unicode): self._input = self._input.encode( self.stdin.encoding or sys.getdefaultencoding()) while self._fd2file: try: ready = poller.poll(self._remaining_time(endtime)) except select.error, e: if e.args[0] == errno.EINTR: continue raise self._check_timeout(endtime, orig_timeout) for fd, mode in ready: if mode & select.POLLOUT: chunk = self._input[self._input_offset : self._input_offset + _PIPE_BUF] self._input_offset += os.write(fd, chunk) if self._input_offset >= len(self._input): close_unregister_and_remove(fd) elif mode & select_POLLIN_POLLPRI: data = os.read(fd, 4096) if not data: close_unregister_and_remove(fd) self._fd2output[fd].append(data) else: # Ignore hang up or errors. close_unregister_and_remove(fd) return (stdout, stderr) def _communicate_with_select(self, input, endtime, orig_timeout): if not self._communication_started: self._read_set = [] self._write_set = [] if self.stdin and input: self._write_set.append(self.stdin) if self.stdout: self._read_set.append(self.stdout) if self.stderr: self._read_set.append(self.stderr) if self.stdin and self._input is None: self._input_offset = 0 self._input = input if self.universal_newlines and isinstance(self._input, unicode): self._input = self._input.encode( self.stdin.encoding or sys.getdefaultencoding()) stdout = None # Return stderr = None # Return if self.stdout: if not self._communication_started: self._stdout_buff = [] stdout = self._stdout_buff if self.stderr: if not self._communication_started: self._stderr_buff = [] stderr = self._stderr_buff while self._read_set or self._write_set: try: (rlist, wlist, xlist) = \ select.select(self._read_set, self._write_set, [], self._remaining_time(endtime)) except select.error, e: if e.args[0] == errno.EINTR: continue raise # According to the docs, returning three empty lists indicates # that the timeout expired. if not (rlist or wlist or xlist): raise TimeoutExpired(self.args, orig_timeout) # We also check what time it is ourselves for good measure. self._check_timeout(endtime, orig_timeout) if self.stdin in wlist: chunk = self._input[self._input_offset : self._input_offset + _PIPE_BUF] try: bytes_written = os.write(self.stdin.fileno(), chunk) except EnvironmentError as e: if e.errno == errno.EPIPE: self._write_set.remove(self.stdin) self.stdin.close() else: raise else: self._input_offset += bytes_written if self._input_offset >= len(self._input): self.stdin.close() self._write_set.remove(self.stdin) if self.stdout in rlist: data = os.read(self.stdout.fileno(), 1024) if data == "": self.stdout.close() self._read_set.remove(self.stdout) stdout.append(data) if self.stderr in rlist: data = os.read(self.stderr.fileno(), 1024) if data == "": self.stderr.close() self._read_set.remove(self.stderr) stderr.append(data) return (stdout, stderr) def send_signal(self, sig): """Send a signal to the process """ # Skip signalling a process that we know has already died. if self.returncode is None: os.kill(self.pid, sig) def terminate(self): """Terminate the process with SIGTERM """ self.send_signal(signal.SIGTERM) def kill(self): """Kill the process with SIGKILL """ self.send_signal(signal.SIGKILL)