popen4(), class Popen4: popen4() support for Unix.
popen2(), popen3(): Reversed order of bufsize and mode parameters to
comply with what was here before (Python 1.5.2).
class Popen3: Factored the __init__() into a more basic initializer and
a helper method, to allow some re-use by the Popen4 class.
Use os.dup2() instead of os.dup() to create the proper
file descriptors in the child process.
This closes SourceForge bug #115330 and partially closes #115353.
This commit is contained in:
Fred Drake
parent
38cb9f1f17
commit
d75e63a865
119
Lib/popen2.py
119
Lib/popen2.py
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@ -8,7 +8,6 @@ and popen3(cmd) which return two or three pipes to the spawned command.
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import os
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import sys
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import string
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MAXFD = 256 # Max number of file descriptors (os.getdtablesize()???)
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@ -22,14 +21,15 @@ class Popen3:
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"""Class representing a child process. Normally instances are created
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by the factory functions popen2() and popen3()."""
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sts = -1 # Child not completed yet
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def __init__(self, cmd, capturestderr=0, bufsize=-1):
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"""The parameter 'cmd' is the shell command to execute in a
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sub-process. The 'capturestderr' flag, if true, specifies that
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the object should capture standard error output of the child process.
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The default is false. If the 'bufsize' parameter is specified, it
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specifies the size of the I/O buffers to/from the child process."""
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if type(cmd) == type(''):
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cmd = ['/bin/sh', '-c', cmd]
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_cleanup()
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p2cread, p2cwrite = os.pipe()
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c2pread, c2pwrite = os.pipe()
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if capturestderr:
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@ -37,25 +37,11 @@ class Popen3:
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self.pid = os.fork()
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if self.pid == 0:
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# Child
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os.close(0)
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os.close(1)
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if os.dup(p2cread) <> 0:
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sys.stderr.write('popen2: bad read dup\n')
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if os.dup(c2pwrite) <> 1:
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sys.stderr.write('popen2: bad write dup\n')
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os.dup2(p2cread, 0)
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os.dup2(c2pwrite, 1)
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if capturestderr:
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os.close(2)
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if os.dup(errin) <> 2: pass
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for i in range(3, MAXFD):
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try:
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os.close(i)
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except: pass
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try:
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os.execvp(cmd[0], cmd)
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finally:
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os._exit(1)
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# Shouldn't come here, I guess
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os._exit(1)
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os.dup2(errin, 2)
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self._run_child(cmd)
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os.close(p2cread)
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self.tochild = os.fdopen(p2cwrite, 'w', bufsize)
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os.close(c2pwrite)
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@ -65,9 +51,21 @@ class Popen3:
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self.childerr = os.fdopen(errout, 'r', bufsize)
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else:
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self.childerr = None
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self.sts = -1 # Child not completed yet
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_active.append(self)
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def _run_child(self, cmd):
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if type(cmd) == type(''):
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cmd = ['/bin/sh', '-c', cmd]
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for i in range(3, MAXFD):
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try:
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os.close(i)
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except:
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pass
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try:
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os.execvp(cmd[0], cmd)
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finally:
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os._exit(1)
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def poll(self):
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"""Return the exit status of the child process if it has finished,
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or -1 if it hasn't finished yet."""
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@ -90,55 +88,72 @@ class Popen3:
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return self.sts
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class Popen4(Popen3):
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childerr = None
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def __init__(self, cmd, bufsize=-1):
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_cleanup()
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p2cread, p2cwrite = os.pipe()
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c2pread, c2pwrite = os.pipe()
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self.pid = os.fork()
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if self.pid == 0:
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# Child
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os.dup2(p2cread, 0)
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os.dup2(c2pwrite, 1)
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os.dup2(c2pwrite, 2)
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self._run_child(cmd)
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os.close(p2cread)
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self.tochild = os.fdopen(p2cwrite, 'w', bufsize)
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os.close(c2pwrite)
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self.fromchild = os.fdopen(c2pread, 'r', bufsize)
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_active.append(self)
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if sys.platform[:3] == "win":
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def popen2(cmd, mode='t', bufsize=-1):
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# Some things don't make sense on non-Unix platforms.
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del Popen3, Popen4, _active, _cleanup
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def popen2(cmd, bufsize=-1, mode='t'):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout, child_stdin) are returned."""
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w, r = os.popen2(cmd, mode, bufsize)
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return r, w
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else:
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def popen2(cmd, mode='t', bufsize=-1):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout, child_stdin) are returned."""
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if type(mode) is type(0) and bufsize == -1:
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bufsize = mode
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mode = 't'
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assert mode in ('t', 'b')
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_cleanup()
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inst = Popen3(cmd, 0, bufsize)
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return inst.fromchild, inst.tochild
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if sys.platform[:3] == "win":
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def popen3(cmd, mode='t', bufsize=-1):
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def popen3(cmd, bufsize=-1, mode='t'):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout, child_stdin, child_stderr) are returned."""
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w, r, e = os.popen3(cmd, mode, bufsize)
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return r, w, e
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else:
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def popen3(cmd, mode='t', bufsize=-1):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout, child_stdin, child_stderr) are returned."""
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if type(mode) is type(0) and bufsize == -1:
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bufsize = mode
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mode = 't'
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assert mode in ('t', 'b')
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_cleanup()
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inst = Popen3(cmd, 1, bufsize)
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return inst.fromchild, inst.tochild, inst.childerr
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if sys.platform[:3] == "win":
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def popen4(cmd, mode='t', bufsize=-1):
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def popen4(cmd, bufsize=-1, mode='t'):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout_stderr, child_stdin) are returned."""
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w, r = os.popen4(cmd, mode, bufsize)
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return r, w
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else:
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pass # not yet on unix
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def popen2(cmd, bufsize=-1, mode='t'):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout, child_stdin) are returned."""
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inst = Popen3(cmd, 0, bufsize)
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return inst.fromchild, inst.tochild
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def popen3(cmd, bufsize=-1, mode='t'):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout, child_stdin, child_stderr) are returned."""
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inst = Popen3(cmd, 1, bufsize)
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return inst.fromchild, inst.tochild, inst.childerr
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def popen4(cmd, bufsize=-1, mode='t'):
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"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
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specified, it sets the buffer size for the I/O pipes. The file objects
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(child_stdout_stderr, child_stdin) are returned."""
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inst = Popen4(cmd, bufsize)
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return inst.fromchild, inst.tochild
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def _test():
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