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Date: Mon, 16 Feb 2004 13:20:31 -0500
From: Christopher Faylor <cgf-no-personal-reply-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: failure of unzip and recent cygwin1.dll
Message-ID: <20040216182031.GB22748@redhat.com>
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References: <OFF0DB63A0 DOT 1B9D77F6-ON85256E3C DOT 005FA048-85256E3C DOT 0060B3C4 AT us DOT ibm DOT com>
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On Mon, Feb 16, 2004 at 12:36:14PM -0500, Thomas L Roche wrote:
>Christopher Faylor Mon, 16 Feb 2004 09:49:19 -0500
>> What you have discovered is that when memcpy is given a NULL pointer
>> it will [cause] a SEGV.
>
>No, I have discovered considerably more. Consequently my question is,
>is the path_conv bad?

What you are debugging is the consequences of cmalloc being NULL.  While
that may illustrate that cygwin should recover more robustly from such a
situation, it is not directly related to the problem at hand, namely,
"Why is cmalloc returning NULL?"

When debugging problems like this, where an error message is displayed,
try to find out where the error message came from and either set a
breakpoint there or, if you can, to save time, work back from that point
to see if you can see an obvious point to set a breakpoint where you can
determine what caused the NULL.

If you look at the changes that I made to cygwin yesterday:

http://cygwin.com/snapshots/winsup-diffs-20040214-20040215

you could set a breakpoint at the line I changed and report on the same
things that is being reported in the malloc_printf.  Or, you could just
send the one line from the strace.  It's possible that previous lines
would also be instructive but rather than spam the list with what might
be useless information, that one line should be useful.  It will show
whether cygwin is just running out of memory or if an internal pointer
is being corrupted.

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