Bugs item #1710802, was opened at 2007-05-01 22:46
Message generated for change (Comment added) made by astrand
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Category: Python Library
Group: None
>Status: Closed
>Resolution: Wont Fix
Priority: 5
Private: No
Submitted By: Patrick Mézard (pmezard)
Assigned to: Peter Åstrand (astrand)
Summary: subprocess must escape redirection characters under win32
Initial Comment:
Hello,
For some reason, subprocess.Popen arguments are not processed correctly when
one of them contains a redirection character ("<>&|") when calling a batch file.
Unittest and patch are attached below. Here are the steps to reproduce it:
callee.py
"""
import sys
print sys.argv
"""
callee.bat
"""
python callee.py %*
"""
caller.py
"""
import subprocess
args = [
'a<b',
'a>b',
'a|b',
'a&b',
]
for arg in args:
subprocess.check_call(['callee.bat', arg])
"""
Then:
"""
>python caller.py
The system cannot find the file specified.
Traceback (most recent call last):
File "caller.py", line 22, in <module>
subprocess.check_call(['callee.bat', arg])
File "C:\Python251\lib\subprocess.py", line 461, in check_call
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['callee.bat', 'a<b']' returned non-zero
exit status 1
"""
With:
"""
Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
"""
----------------------------------------------------------------------
>Comment By: Peter Åstrand (astrand)
Date: 2007-05-04 23:13
Message:
Logged In: YES
user_id=344921
Originator: NO
I'm testing with a simpler pair of files:
callee.bat:
echo arg1 %1
echo arg2 %2
echo arg3 %3
caller.py:
import subprocess
subprocess.call(['callee.bat', 'a<b'])
This fails. What happens is that CreateProcess is called with:
lpApplicationName=None
lpCommandLine="callee.bat a<b"
As far as I know, this is correct: I can't find anything in the
documentation of CreateProcess that indicates that "<" is a magical meta
character in this context. I find it very surprising that CreateProcess
behaves like this.
After some further investigations, I've found out that it's the fact that
we are calling a batch file that's the problem. CreateProcess does not fail
on a command line such as "view.exe a<b". Indeed, the documentation as well
as a community comment on
http://msdn2.microsoft.com/en-us/library/ms682425.aspx indicates that batch
files are handled in a special (broken?) way.
I'm reluctant to accept the attached patch. It might for this particular
situation, but as far as I can tell, we are following the documented API.
You should be able to work around this problem by quoting in your
application.
----------------------------------------------------------------------
Comment By: Neal Norwitz (nnorwitz)
Date: 2007-05-02 08:38
Message:
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Originator: NO
Peter, can you take a look at this?
----------------------------------------------------------------------
Comment By: Patrick Mézard (pmezard)
Date: 2007-05-01 22:47
Message:
Logged In: YES
user_id=1660346
Originator: YES
File Added: fix_subp
----------------------------------------------------------------------
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https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1710802&group_id=5470
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