Patches item #1709112, was opened at 2007-04-28 06:35
Message generated for change (Comment added) made by abkhd
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Category: Tests
Group: Python 2.5
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: A.B., Khalid (abkhd)
Assigned to: Nobody/Anonymous (nobody)
Summary: test_1686475 of test_os & pagefile.sys
Initial Comment:
test_1686475 of test_os appears to rely on the
existence of "pagefile.sys" on the C drive like so:
def test_1686475(self):
# Verify that an open file can be stat'ed
try:
os.stat(r"c:\pagefile.sys")
except WindowsError, e:
if e == 2: # file does not exist; cannot run test
return
self.fail("Could not stat pagefile.sys")
But since pagefile.sys may not be on every C
drive and since the exception object e is not a numeric then that test is
probably going to fail if the pagefile.sys does not exist where it is expected.
In such a case Windows returns "[Error 5] Access is denied:
'c:\\pagefile.sys'". So we need to test if e.winerror == 5 to skip this and
return without failing.
Patch "test_os.patch" is attached.
By the way, I see the same problem in the trunk, so maybe this need to be
applied there as well.
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>Comment By: A.B., Khalid (abkhd)
Date: 2007-04-30 10:01
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Another source seems to suggest that the error message will
differ depending on the Windows version. I think the error
message might be more related to the underlying file system.
Hence since my C drive is formated as FAT WinXP might be
reporting attempted access to the locked pagefile.sys as
ERROR_ACCESS_DENIED, however, in other machines where the
C drive could be formated as an NTFS then the error message
will be changed to SHARING_ERROR_VIOLATION.
This makes sense because pagefile.sys seems to be opened
exclusively by Windows in either case. The error differs
depending on the capability of the file system. And so one
would be expected to test for both errors to see if stat
worked.
Regards,
Khalid
Reference [Search of ERROR_SHARING_VIOLATION] in syscalls.cc of Cygwin:
http://www.koders.com/cpp/fid05B16888E9827D2766C45C718ED8620BC82B4DCE.aspx
pagefile.sys
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Comment By: A.B., Khalid (abkhd)
Date: 2007-04-30 09:07
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I had thought that the file was opened exclusively by Windows
and so the latter denied access to it (including sharing).
However, it might be worth a while to note how others handle
this problem.
Please see ntfs.c of MIT/GNU Scheme:
http://www.koders.com/c/fid3A61BD3B46FA62F5E9F99E5860DCAE5BC2B7FA2C.aspx
and ntfs.h of the same project:
http://www.koders.com/c/fid5FA9A6766ABABAAB4DC09266CA61866F8270A139.aspx
They actually test for both errors in addtion to ERROR_DRIVE_LOCKED to
determine if stat has worked or not.
Regards,
Khalid
More references:
http://www.supportnet.de/stat/2002/7/id98848.asp
http://www.cygwin.com/ml/cygwin/2000-01/msg00274.html
http://ftp.gnu.org/gnu/mit-scheme/stable.pkg/7.7.1/changelog.txt
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Comment By: Martin v. Löwis (loewis)
Date: 2007-04-30 05:16
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Why should I not check for ERROR_SHARING_VIOLATION? The OP complains that
he sees an error "The process cannot access the file because it is being
used by another process" in 2.5.0, and can stat the file in 2.4. So it is
clearly ERROR_SHARING_VIOLATION that is being returned (also on the system
on which I developed the patch).
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Comment By: A.B., Khalid (abkhd)
Date: 2007-04-30 01:52
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Please see http://www.python.org/sf/1686475 for reference.
Martin,
I think you should be checking for ERROR_ACCESS_DENIED not
ERROR_SHARING_VIOLATION as you do in your patch to r54685 and r54686. The
attached posixmodule patch fixes this issue for me on MinGW. Can you try it
out?
File Added: test_1686475.patch
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