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Re: Adding MSYS functionality to Cygwin
- From: Christopher Faylor <cgf-use-the-mailinglist-please at cygwin dot com>
- To: cygwin at cygwin dot com
- Date: Wed, 19 Jun 2013 13:45:14 -0400
- Subject: Re: Adding MSYS functionality to Cygwin
- References: <CABEPuQJDLjtbcLig1isTUJgb6RBCD8LNShbm9mTPcb9WM5S5fw at mail dot gmail dot com> <51C0B08E dot 8080900 at etr-usa dot com> <CABEPuQJJpRfPKSwZ7M0eTOdp1HxDcmvuy1=qXFHBw-8kLkZ1ZQ at mail dot gmail dot com> <51C0D956 dot 4090905 at etr-usa dot com> <20130619020234 dot GA3669 at ednor dot casa dot cgf dot cx> <51C1EAA3 dot 6040307 at etr-usa dot com>
- Reply-to: cygwin at cygwin dot com
On Wed, Jun 19, 2013 at 11:30:11AM -0600, Warren Young wrote:
>On 6/18/2013 20:02, Christopher Faylor wrote:
>> On Tue, Jun 18, 2013 at 04:04:06PM -0600, Warren Young wrote:
>>> It would be possible, though somewhat evil, for Cygwin's exec()
>>> implementation to peek at the DLL dependency list of a program before
>>> starting it, and from that infer whether it should automatically
>>> translate paths.
>> Cygwin already does this. It detects whether the program it is about
>> to run uses the Cygwin DLL and, if not, makes decisions on how to
>> handle exec. It would be relatively easy to extend this.
>Well, given that we're already paying the "peek" cost, I don't have any
>objection to making exec() take longer for the native Windows case only.
>Do you know how you want to cope with my contrived "xcopy /bin a b"
>example? The point of the example, of course, is that "/bin" looks like
>a real, existing POSIX path, but isn't.
I don't think people are getting this:
*How this is implemented doesn't matter*.
I'm talking about providing hooks so that an add-on MSYS dll could
modify the windows command-line. Then we wouldn't care what MSYS does
with the command-line since it isn't a Cygwin DLL decision. The goal is
to allow a small DLL to hook into Cygwin and do whatever MSYS wants to
callout (CO_EXEC, &command_line);
Where it is expected that the command line could be modified.
The "check-for-windows" code is already there. Calling out would be
close to a no-op in the non-MSYS cost. Otherwise, I really don't care
what it costs.
I understand the objections to the way that MSYS does things. I really
do. I don't like what it does, either (and I've voiced the same
objections in the past) but we're willing to selectively modify Cygwin
to allow it to be used as the engine that drives future MSYS
development. The goal would be to collapse the fork back into Cygwin
with minimal cost to the Cygwin DLL.
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