1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef LIBMEMUNREACHABLE_SCOPED_ALARM_H_
18 #define LIBMEMUNREACHABLE_SCOPED_ALARM_H_
19 
20 #include <signal.h>
21 #include <sys/time.h>
22 
23 #include <chrono>
24 #include <functional>
25 
26 namespace android {
27 
28 class ScopedAlarm {
29  public:
ScopedAlarm(std::chrono::microseconds us,std::function<void ()> func)30   ScopedAlarm(std::chrono::microseconds us, std::function<void()> func) {
31     func_ = func;
32     struct sigaction oldact {};
33     struct sigaction act {};
34     act.sa_handler = [](int) { ScopedAlarm::func_(); };
35     sigaction(SIGALRM, &act, &oldact);
36 
37     std::chrono::seconds s = std::chrono::duration_cast<std::chrono::seconds>(us);
38     itimerval t = itimerval{};
39     t.it_value.tv_sec = s.count();
40     t.it_value.tv_usec = (us - s).count();
41     setitimer(ITIMER_REAL, &t, NULL);
42   }
~ScopedAlarm()43   ~ScopedAlarm() {
44     itimerval t = itimerval{};
45     setitimer(ITIMER_REAL, &t, NULL);
46     struct sigaction act {};
47     act.sa_handler = SIG_DFL;
48     sigaction(SIGALRM, &act, NULL);
49   }
50 
51  private:
52   static std::function<void()> func_;
53 };
54 
55 }  // namespace android
56 
57 #endif
58