[TCLCORE] Re: TIP #175: Add an -async Option to [open]

[Neil M. <ne...@cs...>]

CC'ing tcl-core, as I just realised I forgot to the first time round, 
so this discussion had inadvertantly moved away from the list.


On 29 Mar 2004, at 20:27, Peter da Silva wrote:

>> Well, only files which exactly match "-async" (or a prefix of). Given
>> the current spec:
>>
>> open "-async"
>>
>> would error, as [open] would think no filename had been given.
>>
>> open "-async" w
>>
>> (for instance), would try to open a file named "w" for reading
>> asynchronously. This is why I added the "--" end of options specifier,
>> but you are right that existing applications would need to be 
>> modified,
>> which perhaps isn't the best solution.
>
> Yah. Like I said, I'm worried about the security implications. If you 
> can
> sneak a filename "-async" into an existing script then you could cause
> a previously impossible failure or success in a program that's 
> security-
> critical. It's a small hole, but a lot of security problems in websites
> have used small holes.
>
>> This could be done. I modelled the option on how [socket] does things,
>> but I'm not particularly attached to that way of doing things.
>
> It would keep existing programs from failing, because you can't 
> currently
> have "-async" at that end of the arguments. Another option would be to 
> add
> an "a" flag, maybe?
>
> 	open filename "ra"

That would also be acceptable. My current thinking is to implement this 
via the "mode" parameter at the C level, so this would actually fit 
quite well.

Neil.