Bug#641580: dizzy: should fail when no display can be used

[Witold Baryluk]

Package: dizzy
Version: 0.2-1
Severity: normal

First dizzy works on my account.


However when I use xterm and 
do 'su someotheruser' I have some error handling problems.
I started dizzy there. I got strange screen (like text console
on tty0). Mouse was visible, but no other windows
was shown. Mouse is still changing shape when
I move it arround. However nothing is drawn/redrawn on screen.
I needed to go to real console Ctrl-Alt-F1, and back Ctrl-Alt-F7
to restore graphics.
Then I saw in terminal that dizzy ended with 'Segmentation fault'.

This other account have DISPLAY set (inherited from first user),
but it doesn't have permission (as it doesn't have permision
to the file pointed by XAUTHORITY) to use it.

When I set xhost +, or change permissions, or run dizzy
from root, it works.

It looks that dizzy doesn't check if connecting
to Xserver actually was sucessful.

In gdb I have this

(gdb) r
Starting program: /usr/bin/perl /usr/games/dizzy
[Thread debugging using libthread_db enabled]
No protocol specified
No protocol specified
init kbd.

Program received signal SIGSEGV, Segmentation fault.
0xb75963e0 in SDL_GL_SetAttribute () from /usr/lib/libSDL-1.2.so.0
(gdb) bt
#0  0xb75963e0 in SDL_GL_SetAttribute () from /usr/lib/libSDL-1.2.so.0
#1  0xb764da5e in XS_SDL_GLSetAttribute () from /usr/lib/perl5/auto/SDL_perl/SDL_perl.so
#2  0x080e3c63 in Perl_pp_entersub ()
#3  0x080db232 in Perl_runops_standard ()
#4  0x08081db1 in perl_run ()
#5  0x080657af in main ()


Program crashes after I go to Ctrl-Alt-F1,
and then go back Ctrl-Alt-F1.


Why actually screen turns console-like is also mistery
(maybe some remanents in the framebuffer,
but how then It have rights to do something
like that, if it doesn't have right to use Xserver).
Maybe some error in the driver.


-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.0.0-1-686-pae (SMP w/1 CPU core)
Locale: LANG=pl_PL.UTF-8, LC_CTYPE=pl_PL.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to pl_PL.UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages dizzy depends on:
ii  libconvert-color-perl  0.08-1        
ii  libopengl-perl         0.62+dfsg-1+b1
ii  libsdl-perl            2.2.5-1+b2    
ii  perl                   5.12.4-4      

dizzy recommends no packages.

dizzy suggests no packages.

-- no debconf information