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Diffstat (limited to 'lib/python2.7/popen2.py')
| -rw-r--r-- | lib/python2.7/popen2.py | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/lib/python2.7/popen2.py b/lib/python2.7/popen2.py new file mode 100644 index 0000000..cb769f8 --- /dev/null +++ b/lib/python2.7/popen2.py @@ -0,0 +1,201 @@ +"""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"]) |