To: cygwin@cygwin.com
From: Andrew DeFaria <Andrew@DeFaria.com>
Subject:  Re: UNZIP: Why don't .exe/.dll files get eXecute privs?
Date:  Mon, 17 Aug 2009 21:42:16 -0700
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On 08/17/2009 12:32 PM, Warren Young wrote:
> Jim Reisert AD1C wrote:
>>
>> I can't control how the ZIP file gets created, but I do expect that
>> when I unzip a file, that the .exe will actually execute without
>> having to change permissions!
>
> I guess it comes down to a question of whether *.exe implies chmod +x. 
> It doesn't in any "native" *ix packaging format, like tar or cpio. 
> Doing this would thus be a break from expected behavior for some.  I 
> can see your point, Jim, but I don't think the answer is obvious.
>
> Should unzip do this for *.sh?  *.pl?  *.insert-yfl-extension?
Sure, why not?
> Before you answer, have you looked at a programming language list 
> lately? There are "only" about 750 on this index page in Wikipedia:
>
>     http://en.wikipedia.org/wiki/List_of_programming_languages
>
> I've seen other lists that put the count at more like 2,500.  
> Obviously we don't have to handle them all, as some may re-use 
> extensions, and others aren't directly executable from a shell, like C 
> code.  We're still left with hundreds, surely?  If we don't have to 
> handle them all, what's the razor that describes which get this 
> special treatment and which don't?  How do you deal with conflicts 
> among file name extensions?
Computers are good at handling large lists of things...
>
> Now throw in shebang magic.  Does unzip have to set the executable bit 
> on files with a shebang line at the start?
Great idea!
> What if it's binary data that just happens to start with those two bytes?
You obviously need to look at more than just those two...
> Now does unzip have to parse the line and check for the existence of 
> an interpreter?
Another good idea!
> Should unzip have this special-case code only if it doesn't see an 
> ACL, or does it override explicit settings?
>
> This isn't Cygwin-specific.  I use a package on Linux that uses zip 
> for its distributed binary packages (yeah, yech, I know), and has a 
> bunch of chmod hackery in its post-unpack installation instructions.
Only 1/2 a smiley smirk...
-- 
Andrew DeFaria <http://defaria.com>
What happened to Preparations A through G?


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