[libfuzzer] use timer_create() instead of setitimer() for linux

[MinxuanZ]

SetTimer() now uses setitimer() to sending SIGALRM every UnitTimeoutSec/2 + 1 s
Set UnitTimeoutSec with the -timeout= option

"POSIX.1-2008 marks getitimer() and setitimer() obsolete" and also has some issues regarding accuracy of the timers under load . See https://linux.die.net/man/2/setitimer.
I propose using timer_create() and sigaction() ,See http://man7.org/linux/man-pages/man2/timer_create.2.html

test result on my x86_64 linux

make check-fuzzer

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[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Min (MinxuanZ)

Changes

SetTimer() now uses getitimer() to sending SIGALRM every UnitTimeoutSec/2 + 1 s
Set UnitTimeoutSec with the -timeout= option

"POSIX.1-2008 marks getitimer() and setitimer() obsolete" and also has some issues regarding accuracy of the timers under load . See https://linux.die.net/man/2/setitimer.
I propose using timer_create() and sigaction() ,See http://man7.org/linux/man-pages/man2/timer_create.2.html

test result on my x86_64 linux

make check-fuzzer

---

Full diff: https://github.com/llvm/llvm-project/pull/110274.diff

1 Files Affected:

• (modified) compiler-rt/lib/fuzzer/FuzzerUtilPosix.cpp (+8-3)

diff --git a/compiler-rt/lib/fuzzer/FuzzerUtilPosix.cpp b/compiler-rt/lib/fuzzer/FuzzerUtilPosix.cpp
index 392c1e5be4eea3..469e4ed0661908 100644
--- a/compiler-rt/lib/fuzzer/FuzzerUtilPosix.cpp
+++ b/compiler-rt/lib/fuzzer/FuzzerUtilPosix.cpp
@@ -104,11 +104,16 @@ bool ExecuteCommand(const Command &Cmd, std::string *CmdOutput) {
 }
 
 void SetTimer(int Seconds) {
-  struct itimerval T {
+  timer_t timerid;
+  struct itimerspec T {
     {Seconds, 0}, { Seconds, 0 }
   };
-  if (setitimer(ITIMER_REAL, &T, nullptr)) {
-    Printf("libFuzzer: setitimer failed with %d\n", errno);
+  if (timer_create(CLOCK_REALTIME, NULL, &timerid) == -1) {
+    Printf("libFuzzer: timer_create failed with %d\n", errno);
+    exit(1);
+  }
+  if (timer_settime(timerid, 0, &T, NULL) == -1) {
+    Printf("libFuzzer: timer_settime failed with %d\n", errno);
     exit(1);
   }
   SetSigaction(SIGALRM, AlarmHandler);

[MinxuanZ]

Ping