On Jun 24 13:26, Josh Thompson wrote:
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> On Monday, June 22, 2020 4:11:35 PM EDT Ken Brown wrote:
> > On 6/15/2020 12:21 PM, Josh Thompson wrote:
> > > We recently noticed a change in double quote (") handling that is causing
> > > a
> >
> > > command we issue to fail. The command is:
> > [...]
> >
> > > 3.1.4:
> > > $ cmd.exe /c "echo \""
> > > "
> > >
> > > 3.1.5:
> > > $ cmd.exe /c "echo \""
> > > \"
> >
> > I can confirm this change in behavior, and I thought it would be completely
> > trivial to do a bisection to find the commit that caused it. Unfortunately,
> > it seems that the issue is somehow tied up with the fact that the toolchain
> > used for building the cygwin package was upgraded shortly after the release
> > of 3.1.4.
> >
> > An attempt to rebuild 3.1.4 with the current toolchain fails because of some
> > gcc/binutils changes. So I applied the attached patches, which were
> > applied to the Cygwin git master shortly after the release of 3.1.4, in
> > order to make the build succeed.
> >
> > After installing the rebuilt 3.1.4, however, the cmd.exe call above exhibits
> > the "3.1.5" behavior rather than the "3.1.4" behavior. I can't see
> > anything in the patches that would explain this. I thought maybe it was a
> > compiler optimization problem, but rebuilding without optimization doesn't
> > change anything.
> >
> > I'm stumped.
> >
> > Ken
>
> Hi Ken,
>
> Thanks for your testing on this and for following up. How strange - I
> totally
> wouldn't have expected a toolchain upgrade to have changed how quotes get
> handled.
>
> It sounds like it will be difficult to change the quote behavior. So, we'll
> work to get VCL updated to handle the new behavior.
I have a fix for that. It's a long standing bug, a buffer overrun,
which seem to have had no effect pre-3.1.5 only because the older GCC
toolchain had a subtily different stack allocation strategy.
I uploaded developer snapshots to https://cygwin.com/snapshots/
for testing. Please give this a try and report back.
If this fixes your problem, the bug is serious enough to qualify for
a Cygwin 3.1.6 RSN.
Thanks,
Corinna
--
Corinna Vinschen
Cygwin Maintainer
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