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Re: ksh on cygwin

On Thu, Jan 10, 2002 at 09:13:01AM -0500, Fleischer, Karsten (K.) wrote:
> > > It's a whole bunch of small fixes. I think I need to fill 
> > out the assignment form.
> > 
> > Yeah, please send it as soon as possible since you'll have to send
> > it by snail mail.  Sometimes it takes two to three weeks for some
> > reason.
> OK, I'll fill it out later today.

Fine.  We can need everybody who dares to change Cygwin ;-)

> > It will result in dubious problems
> > when a process mmaps a file.  For instance, the latest gcc expects to
> > be able to read over the end of an mmaped file if the size is not a
> > multiple of getpagesize().  Now think of a file which is 
> > coincidentally
> > exactly 1 page long...
> Glenn found some test cases where mmap() failed and has also written a nice test program. I will get this to you later.
> He also states that the value returned by getpagesize() must conform to mmap() alignment by definition in the SUSv2. I'm not quite sure about that, though.

See my reply to Robert.  It's just an example.  I don't have another
reason at hand now but we already considered that change and we
actually *had* reasons to avoid it.  Perhaps Chris can help out here.

> > We have some vfork() changes in the meantime and even ash had an 
> > related error which should be fixed.
> Maybe we fixed the same error. I'll send you the details.

Please compare with the current CVS.  Vfork() isn't in my expertise.

> > > - use the contents of $SHELL instead of /bin/sh for 
> > execvp()/execlp() and system() (with some additional checks, 
> > e.g. do not use a csh, use only 'trusted' shells from /bin, 
> > /usr/bin, /usr/local/bin etc.). This allows the user to 
> > select his favorite shell manually, so no more "copy 
> > /bin/bash to /bin/sh" troubles. (This is also from UWIN).
> > 
> > Hmm, interesting idea...
> OK, more detailed. I allow only absolute pathes in $SHELL and don't allow any *csh.
> If superuser then only shells from [/usr][/local]/bin are considered trusted shells.
> If not superuser shells from other directories are allowed, but if uid != euid or gid != egid the shell and the directory where it resides must not be writable.
> Fall back value is /bin/sh.

But, uhm, what exactly is a `superuser' from your point of view?
We don't have that concept except for SYSTEM as _the_ user which
is able to change user context w/o changing security policies.
And on 9x/Me...

> > > - utime() doesn't mark st_ctime for update
> > 
> > Really?  I would never think so when inspecting the source code.
> Has this been fixed meanwhile? Also other calls like chmod() must mark st_ctime for update. My patches are not complete here.

I have searched in the ChangeLog since I'm thinking to have a vague
memory about soemthing related.  Unfortunately I couldn't find that.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                      
Red Hat, Inc.

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