Re: 1.5.21-1: sshd: "child_copy: linked dll data write copy failed" after computer reboot (Windows 2000 SP4)

[Dan Harkless <cygwin-list at harkless dot org>]

On November 7, 2006, Matthew Woehlke <mw_triad@users.sourceforge.net> wrote:
> Dan Harkless wrote:
> > Double argh.  After rebooting, I found sshd wasn't running at all.  Looking
> > at /var/log/sshd.log, I found a ton of:
> > 
> >> C:\cygwin\usr\sbin\sshd.exe (1584): *** proc magic mismatch detected -
> >> 0x704D1F7E/0xD079E02.
> 
> This problem is probably due to using incompatible versions of the 
> cygwin DLL.
> 
> > Guess I have to reinstall Cygwin again to get sshd back to its semi-working
> > (just not after a reboot) state?
> 
> >> Search for cygwin1.dll using the Windows Start->Find/Search facility
> >> and delete all but the most recent version.
> 
> ...did you try this?

I did not search in this case because I had never seen these types of sshd
crash popups before and I was assuming they were a result of the
'rebaseall' and that I should just reinstall again.

However, I have had issues in the past few months where suddenly commands in
my bash window would start failing with the "probably due to using
incompatible versions of the cygwin DLL" error (without crash popups).  When
that first occurred, I did a search and found no other copies of
cygwin1.dll.  Also, in those cases, rebooting the machine would fix the
problem, which would seem to indicate it was not due to there being multiple
'cygwin1.dll's in the PATH.  Is it possible a statically linked application
using Cygwin code could cause this error, if it were running at the time?

When I reinstalled Cygwin the first time, yesterday, setup.exe gave me an
error saying that there was an older copy of cygwin1.dll in
C:\WINNT\system32 and asked if it could delete it.  I wasn't sure who might
have put it there, so I made a copy of it in a data folder on my D: drive
and then told it it could delete it, but got an error popup afterwards
saying that it had been unable to do so.  I then went to go delete it with
Windows Explorer and had no problem doing so.  I believe I restarted the
install after that.

Today when I reinstalled Cygwin again, setup.exe told me that
C:\WINNT\system32\cygwin1.dll was back, even though I had confirmed deletion
yesterday.  Does Cygwin itself ever install the DLL there?  If not, I guess
there's some application on my system that does, and that repaired itself by
putting it back after I deleted it yesterday.  I have a few video codecs,
converters, and players (some of which were installed last night) that I
believe use code that was originally written for Linux, so it's possible
it's from one of them.

I once again made a safety copy of the cygwin1.dll file, told setup.exe it
could delete it, it failed to do so, and then I deleted it with Windows
Explorer and then deleted C:\cygwin and restarted the install once more from
scratch.

After rebooting, as I mentioned, sshd's "child_copy: linked dll data write
copy failed" error was occurring again, and I checked and there is *not* a
C:\WINNT\system32\cygwin1.dll file right now.  It has stayed deleted for now
and it is evidently not the culprit in the child_copy issue.

I did another search for cygwin1.dll, and the only other copies I have on my
system are under that D: data directory (not in the PATH) where I saved the
safety copies of the 'cygwin1.dll' files in system32 before deleting them,
the copy in C:\cygwin.renamed\bin (my old, renamed Cygwin installation that
I previously mentioned -- also not in the PATH), and a copy in
C:\SW\Other\Exact_Audio_Copy-0.95_beta_4\CDRDAO.  That copy is also not in
the PATH, I have not run EAC in the last couple of months, and I'm pretty
sure it does not run any process unless you explicitly run the application.

The timestamp on the C:\WINNT\system32\cygwin1.dll file that I deleted
yesterday, BTW, as WELL as the copy that magically came back some time today
is June 26, 2005.  I'm not sure what the best way to get the version number
from cygwin1.dll is.  I tried 'strings -e l cygwin1.dll | fgrep 1.' and got:

    1.5.17
    cygwin1.dll
    cygwin1.dll
    1.5.17

In any event, this C:\WINNT\system32\cygwin1.dll file seems to be an
unrelated issue to my sshd "child_copy: linked dll data write copy failed"
errors, since it currently does not exist yet I am getting those errors.

I did notice that there is a C:\WINNT\system32\cygz.dll file, dated June 21,
2005 (I tried various 'strings' commandlines on it but didn't get anything
that looked like a version number).  Is it feasible it could be causing sshd
to misbehave after reboot until it's restarted?  Perhaps I should try making
a safety copy of it, reboot, and see if sshd allows connections without
being restarted.

-- 
Dan Harkless
http://harkless.org/dan/

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