int
main(int argc, char *argv[])
{
stack_t sigstack;
struct sigaction sa;
int j;
printf("Top of standard stack is near %10p\n", (void *) &j);
/* Allocate alternate stack and inform kernel of its existence */
sigstack.ss_sp = malloc(SIGSTKSZ);
if (sigstack.ss_sp == NULL)
errExit("malloc");
sigstack.ss_size = SIGSTKSZ;
sigstack.ss_flags = 0;
if (sigaltstack(&sigstack, NULL) == -1)
errExit("sigaltstack");
printf("Alternate stack is at %10p-%p\n",
sigstack.ss_sp, (char *) sbrk(0) - 1);
sa.sa_handler = sigsegvHandler; /* Establish handler for SIGSEGV */
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_ONSTACK; /* Handler uses alternate stack */
if (sigaction(SIGSEGV, &sa, NULL) == -1)
errExit("sigaction");
overflowStack(1);
}
int main(int argc,char *argv[])
{
stack_t sigstack;
struct sigaction sa;
int j;
printf("Top of standard stack is near %10p\n",(void *)&j);
sigstack.ss_sp = malloc(SIGSTKSZ);
if(sigstack.ss_sp == NULL) {
perror("malloc");
exit(EXIT_FAILURE);
}
sigstack.ss_size = SIGSTKSZ;
sigstack.ss_flags = 0;
if(sigaltstack(&sigstack,NULL) == -1) {
perror("sigalstack");
exit(EXIT_FAILURE);
}
printf("Alternate stack is at %10p-%p\n",
sigstack.ss_sp,(char*)sbrk(0) - 1);
sa.sa_handler = sigsegvHandler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_ONSTACK;
if(sigaction(SIGSEGV,&sa,NULL) == -1) {
perror("sigaction");
exit(EXIT_FAILURE);
}
overflowStack(1);
}
static void /* A recursive function that overflows the stack */
overflowStack(int callNum)
{
char a[100000]; /* Make this stack frame large */
printf("Call %4d - top of stack near %10p\n", callNum, &a[0]);
overflowStack(callNum+1);
}
static void overflowStack(int callNum)
{
char a[100000];
printf("Call %4d - top of stack near %10p\n",callNum,&a[0]);
overflowStack(callNum + 1);
}
