37 lines · c
1#include <signal.h>2#include <unistd.h>3#include <stdlib.h>4#include <sys/mman.h>5#include <stdio.h>6#include <mach/mach.h>7#include <mach/mach_vm.h>8 9int *g_int_ptr = NULL;10size_t g_size = 10*sizeof(int);11 12void13saction_handler(int signo, siginfo_t info, void *baton) {14 printf("Got into handler.\n"); // stop here in the signal handler15 kern_return_t success16 = mach_vm_protect(mach_task_self(), (mach_vm_address_t) g_int_ptr,17 g_size, 0, VM_PROT_READ|VM_PROT_WRITE);18 g_int_ptr[1] = 20;19}20int21main()22{23 kern_return_t vm_result = vm_allocate(mach_task_self(), &g_int_ptr, g_size, VM_FLAGS_ANYWHERE);24 for (int i = 0; i < 10; i++)25 g_int_ptr[i] = i * 10;26 27 vm_result = mach_vm_protect(mach_task_self(), (mach_vm_address_t) g_int_ptr, g_size, 0, VM_PROT_NONE);28 struct sigaction my_action;29 sigemptyset(&my_action.sa_mask);30 my_action.sa_handler = (void (*)(int)) saction_handler;31 my_action.sa_flags = SA_SIGINFO;32 33 sigaction(SIGBUS, &my_action, NULL); // Stop here to get things going.34 int local_value = g_int_ptr[1];35 return local_value; // Break here to make sure we got past the signal handler36}37