llvm-project/llvm/lib/System/Unix/Alarm.inc

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//===-- Alarm.inc - Implement Unix Alarm Support ----------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the UNIX Alarm support.
//
//===----------------------------------------------------------------------===//
#include <signal.h>
#include <unistd.h>
#include <cassert>
using namespace llvm;
/// AlarmCancelled - This flag is set by the SIGINT signal handler if the
/// user presses CTRL-C.
static volatile bool AlarmCancelled = false;
/// AlarmTriggered - This flag is set by the SIGALRM signal handler if the
/// alarm was triggered.
static volatile bool AlarmTriggered = false;
/// NestedSOI - Sanity check. Alarms cannot be nested or run in parallel.
/// This ensures that they never do.
static bool NestedSOI = false;
static RETSIGTYPE SigIntHandler(int Sig) {
AlarmCancelled = true;
signal(SIGINT, SigIntHandler);
}
static RETSIGTYPE SigAlarmHandler(int Sig) {
AlarmTriggered = true;
}
static void (*OldSigIntHandler) (int);
void sys::SetupAlarm(unsigned seconds) {
assert(!NestedSOI && "sys::SetupAlarm calls cannot be nested!");
NestedSOI = true;
AlarmCancelled = false;
AlarmTriggered = false;
::signal(SIGALRM, SigAlarmHandler);
OldSigIntHandler = ::signal(SIGINT, SigIntHandler);
::alarm(seconds);
}
void sys::TerminateAlarm() {
assert(NestedSOI && "sys::TerminateAlarm called without sys::SetupAlarm!");
::alarm(0);
::signal(SIGALRM, SIG_DFL);
::signal(SIGINT, OldSigIntHandler);
AlarmCancelled = false;
AlarmTriggered = false;
NestedSOI = false;
}
int sys::AlarmStatus() {
if (AlarmCancelled)
return -1;
if (AlarmTriggered)
return 1;
return 0;
}