void kscrashsentry_uninstall(KSCrashType crashTypes)
{
KSLOG_DEBUG("Uninstalling handlers with crash types 0x%x.", crashTypes);
if(crashTypes & KSCrashTypeMachException)
{
kscrashsentry_uninstallMachHandler();
}
if(crashTypes & KSCrashTypeSignal)
{
kscrashsentry_uninstallSignalHandler();
}
if(crashTypes & KSCrashTypeNSException)
{
kscrashsentry_uninstallNSExceptionHandler();
}
KSLOG_DEBUG("Uninstall complete.");
}
bool kscrashsentry_installMachHandler(KSCrash_SentryContext* const context)
{
KSLOG_DEBUG("Installing mach exception handler.");
bool attributes_created = false;
pthread_attr_t attr;
kern_return_t kr;
int error;
const task_t thisTask = mach_task_self();
exception_mask_t mask = EXC_MASK_BAD_ACCESS |
EXC_MASK_BAD_INSTRUCTION |
EXC_MASK_ARITHMETIC |
EXC_MASK_SOFTWARE |
EXC_MASK_BREAKPOINT;
if(g_installed)
{
KSLOG_DEBUG("Exception handler already installed.");
return true;
}
g_installed = 1;
if(ksmach_isBeingTraced())
{
// Different debuggers hook into different exception types.
// For example, GDB uses EXC_BAD_ACCESS for single stepping,
// and LLDB uses EXC_SOFTWARE to stop a debug session.
// Because of this, it's safer to not hook into the mach exception
// system at all while being debugged.
KSLOG_WARN("Process is being debugged. Not installing handler.");
goto failed;
}
g_context = context;
KSLOG_DEBUG("Backing up original exception ports.");
kr = task_get_exception_ports(thisTask,
mask,
g_previousExceptionPorts.masks,
&g_previousExceptionPorts.count,
g_previousExceptionPorts.ports,
g_previousExceptionPorts.behaviors,
g_previousExceptionPorts.flavors);
if(kr != KERN_SUCCESS)
{
KSLOG_ERROR("task_get_exception_ports: %s", mach_error_string(kr));
goto failed;
}
if(g_exceptionPort == MACH_PORT_NULL)
{
KSLOG_DEBUG("Allocating new port with receive rights.");
kr = mach_port_allocate(thisTask,
MACH_PORT_RIGHT_RECEIVE,
&g_exceptionPort);
if(kr != KERN_SUCCESS)
{
KSLOG_ERROR("mach_port_allocate: %s", mach_error_string(kr));
goto failed;
}
KSLOG_DEBUG("Adding send rights to port.");
kr = mach_port_insert_right(thisTask,
g_exceptionPort,
g_exceptionPort,
MACH_MSG_TYPE_MAKE_SEND);
if(kr != KERN_SUCCESS)
{
KSLOG_ERROR("mach_port_insert_right: %s", mach_error_string(kr));
goto failed;
}
}
KSLOG_DEBUG("Installing port as exception handler.");
kr = task_set_exception_ports(thisTask,
mask,
g_exceptionPort,
EXCEPTION_DEFAULT,
THREAD_STATE_NONE);
if(kr != KERN_SUCCESS)
{
KSLOG_ERROR("task_set_exception_ports: %s", mach_error_string(kr));
goto failed;
}
KSLOG_DEBUG("Creating secondary exception thread (suspended).");
pthread_attr_init(&attr);
attributes_created = true;
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
error = pthread_create(&g_secondaryThread,
&attr,
&ksmachexc_i_handleExceptions,
kThreadSecondary);
if(error != 0)
{
KSLOG_ERROR("pthread_create_suspended_np: %s", strerror(error));
goto failed;
}
context->reservedThreads[KSCrashReservedThreadTypeMachSecondary] = pthread_mach_thread_np(g_secondaryThread);
KSLOG_DEBUG("Creating primary exception thread.");
error = pthread_create(&g_primaryThread,
&attr,
&ksmachexc_i_handleExceptions,
kThreadPrimary);
if(error != 0)
{
KSLOG_ERROR("pthread_create: %s", strerror(error));
goto failed;
}
pthread_attr_destroy(&attr);
context->reservedThreads[KSCrashReservedThreadTypeMachPrimary] = pthread_mach_thread_np(g_primaryThread);
KSLOG_DEBUG("Mach exception handler installed.");
return true;
failed:
KSLOG_DEBUG("Failed to install mach exception handler.");
if(attributes_created)
{
pthread_attr_destroy(&attr);
}
kscrashsentry_uninstallMachHandler();
return false;
}
