Mail Archives: cygwin/2010/03/12/11:24:04
On Mar 12 16:49, Thomas Wolff wrote:
> On 12.03.2010 16:16, Eric Blake wrote:
> >>...
> >This is an area of active conversation; if you would like, you can test
> >the latest snapshot and the experimental coreutils 8.4-1 to see if the
> >behavior is more intuitive (that is, there are more situations where
> >.exe is preserved across file moves or copies, and fewer places where
> >.exe is appended on a whim if the source didn't have one).
> >
> >In general, cygwin does not care if the .exe is missing, but other
> >programs (particularly cmd) do, so it is better if PE-COFF files are
> >given the .exe extension. But implementing it is tricky - for example,
> >in the case of 'cat a> b', there is no way to tell at the time when b
> >is created whether it will be populated with PE-COFF contents (that is,
> >no way to tell whether the source was a literal 'a' or 'a.exe'), so you
> >will not get an .exe in that case.
> I'm just pondering the bold idea (probably to be discarded) that it
> *could* be detected by "magic number" checking, i.e. renaming a new
> file on-the-fly after a few bytes of PE-COFF have been written to
> its beginning... 8-)
We had a discussion on the cygwin-developer list and I also discussed
this with Eric on IRC and there's no 100% correct solution by guessing
if .exe should be appended or not, one way or another. Your idea isn't
new, U/Win implements something along these lines. But that would fail
just the same way as Cywin in a scenario in which you, for instance,
checkout a binary file without .exe suffix from a git or svn repository.
The new rename(2) implementation can fix a few scenarios, but it will
never be able to do the right thing every time. The same goes for
changing the .exe suffix by checking what is written to the first few
bytes of a file.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
Red Hat
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