limited python virtual machine (WAS: Another scripting language implemented into Python itself?)

[Jack Diederich]

On Wed, Jan 26, 2005 at 10:39:18AM -0800, aurora wrote:
> >On Wed, Jan 26, 2005 at 05:18:59PM +0100, Alexander Schremmer wrote:
> >>On Tue, 25 Jan 2005 22:08:01 +0100, I wrote:
> >>
> >>>>>> sys.safecall(func, maxcycles=1000)
> >>> could enter the safe mode and call the func.
> >>
> >>This might be even enhanced like this:
> >>
> >>>>> import sys
> >>>>> sys.safecall(func, maxcycles=1000,
> >>                 allowed_domains=['file-IO', 'net-IO', 'devices',  
> >>'gui'],
> >>                 allowed_modules=['_sre'])
> >>
> >>Any comments about this from someone who already hacked CPython?
> >
> >Yes, this comes up every couple months and there is only one answer:
> >This is the job of the OS.
> >Java largely succeeds at doing sandboxy things because it was written  
> >that
> >way from the ground up (to behave both like a program interpreter and an  
> >OS).
> >Python the language was not, and the CPython interpreter definitely was  
> >not.
> >
> >Search groups.google.com for previous discussions of this on c.l.py
> >
> It is really necessary to build a VM from the ground up that includes OS  
> ability? What about JavaScript?
> 

See the past threads I reccomend in another just-posted reply.

Common browser implementations of Javascript have almost no features, can't
import C-based libraries, and can easilly enter endless loops or eat all
available memory.  You could make a fork of python that matches that feature
set, but I don't know why you would want to.

-Jack