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Re: OpenSSH on windows Problem

On Thu, Sep 02, 2004 at 06:31:05PM +0000, Cary Lewis wrote:
>simply using cygwin binaries like ssh, perl, bash, etc.  does not
>virally infect a propietary system with the GPL.

The word "virally" is a charged word.

This is really really simple and I don't know why it is so confusing.

If you provide a binary that uses the cygwin DLL, you must also make the
sources available.

If your program uses the cygwin DLL, then your program is GPLed.  You must
provide the source.

If you plan on distributing the cygwin DLL then you must provide the source
for that version of the cygwin DLL.

If you are distributing ssh, perl, bash, etc.  then you are distributing
open source programs and you must provide the source for ssh, perl,
bash, etc.

If your program does not use cygwin and you are not providing any other
open source programs then you don't have to provide the source.

If your program does not use the cygwin DLL but it is on the same
disk as programs that do use the cygwin DLL then your program is not
GPLed and you don't need to provide sources.

>So, if you plan on using sshd and sftp as part of your commerical app, you don 
>not have to license cygwin.

No.  Even if you did provide sshd and sftpd as part of your commercial app,
"licensing cygwin" does not provide you any special benefit since cygwin's
license does not and cannot trump the licensing of sshd and sftp.  Can you
imagine a world where linking with the cygwin DLL would allow Red Hat to
override someone else's license?  I can't imagine any rational basis for
assuming that.

>Any changes you make to sshd or sftp would have to be published.

Well, they would be part of the source code that you distributed and, if
sshd and sftpd are GPLed then you'd have to make the changes obvious.

>You have to check to make sure that distributing cygwin doesn't run you
>afoul of the GPL.
>That being said, I think we should all encourage RedHat to publish
>cygwin under the LGPL to allow cygwin1.dll to be used without virally
>infecting application code.  But that is just my opinion.

Why would Red Hat be interested in eliminating their revenue stream from
licensing cygwin?  Red Hat generously makes cygwin available via the
GPL.  If that doesn't meet your needs then you are free not to use it.


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