move clocksd to system/ (#24761)

old-commit-hash: ca682b389d75f433d28063c8d774460df0c0fa83

system/clocksd/.gitignore

@@ -0,0 +1 @@
+clocksd

system/clocksd/SConscript

@@ -0,0 +1,2 @@
+Import('env', 'common', 'cereal', 'messaging')
+env.Program('clocksd.cc', LIBS=[common, cereal, messaging, 'capnp', 'zmq', 'kj'])

system/clocksd/clocksd.cc

@@ -0,0 +1,73 @@
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include <cstdint>
+#include <cstdio>
+
+// Apple doesn't have timerfd
+#ifdef __APPLE__
+#include <thread>
+#else
+#include <sys/timerfd.h>
+#endif
+
+#include <cassert>
+#include <chrono>
+
+#include "cereal/messaging/messaging.h"
+#include "common/timing.h"
+#include "common/util.h"
+
+ExitHandler do_exit;
+
+int main() {
+  setpriority(PRIO_PROCESS, 0, -13);
+  PubMaster pm({"clocks"});
+
+#ifndef __APPLE__
+  int timerfd = timerfd_create(CLOCK_BOOTTIME, 0);
+  assert(timerfd >= 0);
+
+  struct itimerspec spec = {0};
+  spec.it_interval.tv_sec = 1;
+  spec.it_interval.tv_nsec = 0;
+  spec.it_value.tv_sec = 1;
+  spec.it_value.tv_nsec = 0;
+
+  int err = timerfd_settime(timerfd, 0, &spec, 0);
+  assert(err == 0);
+
+  uint64_t expirations = 0;
+  while (!do_exit && (err = read(timerfd, &expirations, sizeof(expirations)))) {
+    if (err < 0) {
+      if (errno == EINTR) continue;
+      break;
+    }
+#else
+  // Just run at 1Hz on apple
+  while (!do_exit) {
+    util::sleep_for(1000);
+#endif
+
+    uint64_t boottime = nanos_since_boot();
+    uint64_t monotonic = nanos_monotonic();
+    uint64_t monotonic_raw = nanos_monotonic_raw();
+    uint64_t wall_time = nanos_since_epoch();
+
+    MessageBuilder msg;
+    auto clocks = msg.initEvent().initClocks();
+
+    clocks.setBootTimeNanos(boottime);
+    clocks.setMonotonicNanos(monotonic);
+    clocks.setMonotonicRawNanos(monotonic_raw);
+    clocks.setWallTimeNanos(wall_time);
+
+    pm.send("clocks", msg);
+  }
+
+#ifndef __APPLE__
+  close(timerfd);
+#endif
+  return 0;
+}