| """Spawn a command with pipes to its stdin, stdout, and optionally stderr. |
| |
| The normal os.popen(cmd, mode) call spawns a shell command and provides a |
| file interface to just the input or output of the process depending on |
| whether mode is 'r' or 'w'. This module provides the functions popen2(cmd) |
| and popen3(cmd) which return two or three pipes to the spawned command. |
| """ |
| |
| import os |
| import sys |
| import warnings |
| warnings.warn("The popen2 module is deprecated. Use the subprocess module.", |
| DeprecationWarning, stacklevel=2) |
| |
| __all__ = ["popen2", "popen3", "popen4"] |
| |
| try: |
| MAXFD = os.sysconf('SC_OPEN_MAX') |
| except (AttributeError, ValueError): |
| MAXFD = 256 |
| |
| _active = [] |
| |
| def _cleanup(): |
| for inst in _active[:]: |
| if inst.poll(_deadstate=sys.maxint) >= 0: |
| 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 |
| |
| class Popen3: |
| """Class representing a child process. Normally, instances are created |
| internally by the functions popen2() and popen3().""" |
| |
| sts = -1 # Child not completed yet |
| |
| def __init__(self, cmd, capturestderr=False, bufsize=-1): |
| """The parameter 'cmd' is the shell command to execute in a |
| sub-process. On UNIX, 'cmd' may be a sequence, in which case arguments |
| will be passed directly to the program without shell intervention (as |
| with os.spawnv()). If 'cmd' is a string it will be passed to the shell |
| (as with os.system()). The 'capturestderr' flag, if true, specifies |
| that the object should capture standard error output of the child |
| process. The default is false. If the 'bufsize' parameter is |
| specified, it specifies the size of the I/O buffers to/from the child |
| process.""" |
| _cleanup() |
| self.cmd = cmd |
| p2cread, p2cwrite = os.pipe() |
| c2pread, c2pwrite = os.pipe() |
| if capturestderr: |
| errout, errin = os.pipe() |
| self.pid = os.fork() |
| if self.pid == 0: |
| # Child |
| os.dup2(p2cread, 0) |
| os.dup2(c2pwrite, 1) |
| if capturestderr: |
| os.dup2(errin, 2) |
| self._run_child(cmd) |
| os.close(p2cread) |
| self.tochild = os.fdopen(p2cwrite, 'w', bufsize) |
| os.close(c2pwrite) |
| self.fromchild = os.fdopen(c2pread, 'r', bufsize) |
| if capturestderr: |
| os.close(errin) |
| self.childerr = os.fdopen(errout, 'r', bufsize) |
| else: |
| self.childerr = None |
| |
| def __del__(self): |
| # In case the child hasn't been waited on, check if it's done. |
| self.poll(_deadstate=sys.maxint) |
| if self.sts < 0: |
| if _active is not None: |
| # Child is still running, keep us alive until we can wait on it. |
| _active.append(self) |
| |
| def _run_child(self, cmd): |
| if isinstance(cmd, basestring): |
| cmd = ['/bin/sh', '-c', cmd] |
| os.closerange(3, MAXFD) |
| try: |
| os.execvp(cmd[0], cmd) |
| finally: |
| os._exit(1) |
| |
| def poll(self, _deadstate=None): |
| """Return the exit status of the child process if it has finished, |
| or -1 if it hasn't finished yet.""" |
| if self.sts < 0: |
| try: |
| pid, sts = os.waitpid(self.pid, os.WNOHANG) |
| # pid will be 0 if self.pid hasn't terminated |
| if pid == self.pid: |
| self.sts = sts |
| except os.error: |
| if _deadstate is not None: |
| self.sts = _deadstate |
| return self.sts |
| |
| def wait(self): |
| """Wait for and return the exit status of the child process.""" |
| if self.sts < 0: |
| pid, sts = os.waitpid(self.pid, 0) |
| # This used to be a test, but it is believed to be |
| # always true, so I changed it to an assertion - mvl |
| assert pid == self.pid |
| self.sts = sts |
| return self.sts |
| |
| |
| class Popen4(Popen3): |
| childerr = None |
| |
| def __init__(self, cmd, bufsize=-1): |
| _cleanup() |
| self.cmd = cmd |
| p2cread, p2cwrite = os.pipe() |
| c2pread, c2pwrite = os.pipe() |
| self.pid = os.fork() |
| if self.pid == 0: |
| # Child |
| os.dup2(p2cread, 0) |
| os.dup2(c2pwrite, 1) |
| os.dup2(c2pwrite, 2) |
| self._run_child(cmd) |
| os.close(p2cread) |
| self.tochild = os.fdopen(p2cwrite, 'w', bufsize) |
| os.close(c2pwrite) |
| self.fromchild = os.fdopen(c2pread, 'r', bufsize) |
| |
| |
| if sys.platform[:3] == "win" or sys.platform == "os2emx": |
| # Some things don't make sense on non-Unix platforms. |
| del Popen3, Popen4 |
| |
| def popen2(cmd, bufsize=-1, mode='t'): |
| """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may |
| be a sequence, in which case arguments will be passed directly to the |
| program without shell intervention (as with os.spawnv()). If 'cmd' is a |
| string it will be passed to the shell (as with os.system()). If |
| 'bufsize' is specified, it sets the buffer size for the I/O pipes. The |
| file objects (child_stdout, child_stdin) are returned.""" |
| w, r = os.popen2(cmd, mode, bufsize) |
| return r, w |
| |
| def popen3(cmd, bufsize=-1, mode='t'): |
| """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may |
| be a sequence, in which case arguments will be passed directly to the |
| program without shell intervention (as with os.spawnv()). If 'cmd' is a |
| string it will be passed to the shell (as with os.system()). If |
| 'bufsize' is specified, it sets the buffer size for the I/O pipes. The |
| file objects (child_stdout, child_stdin, child_stderr) are returned.""" |
| w, r, e = os.popen3(cmd, mode, bufsize) |
| return r, w, e |
| |
| def popen4(cmd, bufsize=-1, mode='t'): |
| """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may |
| be a sequence, in which case arguments will be passed directly to the |
| program without shell intervention (as with os.spawnv()). If 'cmd' is a |
| string it will be passed to the shell (as with os.system()). If |
| 'bufsize' is specified, it sets the buffer size for the I/O pipes. The |
| file objects (child_stdout_stderr, child_stdin) are returned.""" |
| w, r = os.popen4(cmd, mode, bufsize) |
| return r, w |
| else: |
| def popen2(cmd, bufsize=-1, mode='t'): |
| """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may |
| be a sequence, in which case arguments will be passed directly to the |
| program without shell intervention (as with os.spawnv()). If 'cmd' is a |
| string it will be passed to the shell (as with os.system()). If |
| 'bufsize' is specified, it sets the buffer size for the I/O pipes. The |
| file objects (child_stdout, child_stdin) are returned.""" |
| inst = Popen3(cmd, False, bufsize) |
| return inst.fromchild, inst.tochild |
| |
| def popen3(cmd, bufsize=-1, mode='t'): |
| """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may |
| be a sequence, in which case arguments will be passed directly to the |
| program without shell intervention (as with os.spawnv()). If 'cmd' is a |
| string it will be passed to the shell (as with os.system()). If |
| 'bufsize' is specified, it sets the buffer size for the I/O pipes. The |
| file objects (child_stdout, child_stdin, child_stderr) are returned.""" |
| inst = Popen3(cmd, True, bufsize) |
| return inst.fromchild, inst.tochild, inst.childerr |
| |
| def popen4(cmd, bufsize=-1, mode='t'): |
| """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may |
| be a sequence, in which case arguments will be passed directly to the |
| program without shell intervention (as with os.spawnv()). If 'cmd' is a |
| string it will be passed to the shell (as with os.system()). If |
| 'bufsize' is specified, it sets the buffer size for the I/O pipes. The |
| file objects (child_stdout_stderr, child_stdin) are returned.""" |
| inst = Popen4(cmd, bufsize) |
| return inst.fromchild, inst.tochild |
| |
| __all__.extend(["Popen3", "Popen4"]) |
