/**
* Run execution forwards for |ctx| until |ctx->trace.rbc| is reached,
* and the $ip reaches the recorded $ip. After that, deliver |sig| if
* nonzero. Return 0 if successful or 1 if an unhandled interrupt
* occurred.
*/
static int emulate_async_signal(struct context* ctx, uint64_t rcb,
const struct user_regs_struct* regs, int sig,
int stepi)
{
if (advance_to(ctx, rcb, regs, 0, stepi)) {
return 1;
}
if (sig) {
emulate_signal_delivery();
}
stop_hpc(ctx);
return 0;
}
void rep_process_signal(struct context *ctx)
{
struct trace* trace = &(ctx->trace);
int tid = ctx->child_tid;
int sig = -trace->stop_reason;
/* if the there is still a signal pending here, two signals in a row must be delivered?\n */
assert(ctx->child_sig == 0);
switch (sig) {
/* set the eax and edx register to the recorded values */
case -SIG_SEGV_RDTSC:
{
struct user_regs_struct regs;
int size;
/* goto the event */
goto_next_event(ctx);
/* make sure we are there */
assert(WSTOPSIG(ctx->status) == SIGSEGV);
char* inst = get_inst(tid, 0, &size);
assert(strncmp(inst,"rdtsc",5) == 0);
read_child_registers(tid, ®s);
regs.eax = trace->recorded_regs.eax;
regs.edx = trace->recorded_regs.edx;
regs.eip += size;
write_child_registers(tid, ®s);
sys_free((void**) &inst);
compare_register_files("rdtsv_now", ®s, "rdsc_rec", &ctx->trace.recorded_regs, 1, 1);
/* this signal should not be recognized by the application */
ctx->child_sig = 0;
break;
}
case -USR_SCHED:
{
assert(trace->rbc_up > 0);
/* if the current architecture over-counts the event in question,
* substract the overcount here */
reset_hpc(ctx, trace->rbc_up - SKID_SIZE);
goto_next_event(ctx);
/* make sure that the signal came from hpc */
if (fcntl(ctx->hpc->rbc_down.fd, F_GETOWN) == ctx->child_tid) {
/* this signal should not be recognized by the application */
ctx->child_sig = 0;
stop_hpc_down(ctx);
compensate_branch_count(ctx, sig);
stop_hpc(ctx);
} else {
fprintf(stderr, "internal error: next event should be: %d but it is: %d -- bailing out\n", -USR_SCHED, ctx->event);
sys_exit();
}
break;
}
case SIGIO:
case SIGCHLD:
{
/* synchronous signal (signal received in a system call) */
if (trace->rbc_up == 0) {
ctx->replay_sig = sig;
return;
}
// setup and start replay counters
reset_hpc(ctx, trace->rbc_up - SKID_SIZE);
/* single-step if the number of instructions to the next event is "small" */
if (trace->rbc_up <= 10000) {
stop_hpc_down(ctx);
compensate_branch_count(ctx, sig);
stop_hpc(ctx);
} else {
printf("large count\n");
sys_ptrace_syscall(tid);
sys_waitpid(tid, &ctx->status);
// make sure we ere interrupted by ptrace
assert(WSTOPSIG(ctx->status) == SIGIO);
/* reset the penig sig, since it did not occur in the original execution */
ctx->child_sig = 0;
ctx->status = 0;
//DO NOT FORGET TO STOP HPC!!!
compensate_branch_count(ctx, sig);
stop_hpc(ctx);
stop_hpc_down(ctx);
}
break;
}
case SIGSEGV:
{
/* synchronous signal (signal received in a system call) */
if (trace->rbc_up == 0 && trace->page_faults == 0) {
ctx->replay_sig = sig;
return;
}
sys_ptrace_syscall(ctx->child_tid);
sys_waitpid(ctx->child_tid, &ctx->status);
assert(WSTOPSIG(ctx->status) == SIGSEGV);
struct user_regs_struct regs;
read_child_registers(ctx->child_tid, ®s);
assert(compare_register_files("now", ®s, "rec", &ctx->trace.recorded_regs, 1, 1) == 0);
/* deliver the signal */
singlestep(ctx, SIGSEGV, 0x57f);
break;
}
default:
printf("unknown signal %d -- bailing out\n", sig);
sys_exit();
break;
}
}