RE: programs from xterm

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From: Matan Ziv-Av (matan@svgalib.org)
Date: Thu 02 Dec 1999 - 22:26:56 IST


On Wed, 1 Dec 1999, Alain Borel wrote:

> 
> On 01-Dec-99 marco.garuti@gruppopro.it wrote:
> > Svgalib programs can't be run under X (for a user <> root, also with chmod
> > u+s <binfilename>),
> I'm surprised it so much as works for root (without screwing up the display
> horribly, that is).
>  
> > In my case the security is not a problem, I just want only to run some
> > svgalib programs in xtern (without every time [ctrl+alt+Fx] + login), so:
> Yet that's what you need to do to run them using svgalib! This is not
> a security problem, but rather a technical problem.

Alain, your information is outdated. As of 1.2.1? svgalib programs can
be run from within X. This is done as follows: if vga_init() finds that
it runs from X, it allocates a new vt (which is in text mode), and
switches to it. It is now X's responsibility to restore text mode. Then
the svgalib program runs, and when it ends, svgalib restores text modes,
and switches back to the X vt. 

This requires root privileges (for the allocation of a new vt). This is
normally no problem, as svgalib programs must run initially with root
provoleges, but if the program is a suid program, svgalib gives up root
privileges as soon as possible.

I think Marco's problem comes from a program the calls some svgalib
call (vga_setmode, or such) before calling vga_init, but I can't be
sure without knowing which programs are problematic.


> If you want X, forget vanilla svgalib. Maybe you'll be more successful
> than I was at using the svgalib wrapper of GGI.
> http://synergy.caltech.edu/~ggi/links.html

>From my experience, the svgalib wrapper is not good enough for most
programs.

-- 
Matan Ziv-Av.                         matan@svgalib.org


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