Convert aos over to flatbuffers

Everything builds, and all the tests pass.  I suspect that some entries
are missing from the config files, but those will be found pretty
quickly on startup.

There is no logging or live introspection of queue messages.

Change-Id: I496ee01ed68f202c7851bed7e8786cee30df29f5
diff --git a/aos/realtime.cc b/aos/realtime.cc
new file mode 100644
index 0000000..6a80550
--- /dev/null
+++ b/aos/realtime.cc
@@ -0,0 +1,127 @@
+#include "aos/realtime.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <sched.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/prctl.h>
+#include <malloc.h>
+
+#include "glog/logging.h"
+
+namespace FLAG__namespace_do_not_use_directly_use_DECLARE_double_instead {
+extern double FLAGS_tcmalloc_release_rate __attribute__((weak));
+}
+using FLAG__namespace_do_not_use_directly_use_DECLARE_double_instead::
+    FLAGS_tcmalloc_release_rate;
+
+namespace aos {
+namespace logging {
+namespace internal {
+
+// Implemented in aos/logging/context.cc.
+void ReloadThreadName() __attribute__((weak));
+
+}  // namespace internal
+}  // namespace logging
+
+namespace {
+
+void SetSoftRLimit(int resource, rlim64_t soft, bool set_for_root) {
+  bool am_root = getuid() == 0;
+  if (set_for_root || !am_root) {
+    struct rlimit64 rlim;
+    PCHECK(getrlimit64(resource, &rlim) == 0)
+        << ": " << program_invocation_short_name << "-init: getrlimit64("
+        << resource << ") failed";
+
+    rlim.rlim_cur = soft;
+    rlim.rlim_max = ::std::max(rlim.rlim_max, soft);
+
+    PCHECK(setrlimit64(resource, &rlim) == 0)
+        << ": " << program_invocation_short_name << "-init: setrlimit64("
+        << resource << ", {cur=" << (uintmax_t)rlim.rlim_cur
+        << ",max=" << (uintmax_t)rlim.rlim_max << "}) failed";
+  }
+}
+
+}  // namespace
+
+void LockAllMemory() {
+  // Allow locking as much as we want into RAM.
+  SetSoftRLimit(RLIMIT_MEMLOCK, RLIM_INFINITY, false);
+
+  WriteCoreDumps();
+  PCHECK(mlockall(MCL_CURRENT | MCL_FUTURE) == 0)
+      << ": " << program_invocation_short_name << "-init: mlockall failed";
+
+  // Don't give freed memory back to the OS.
+  CHECK_EQ(1, mallopt(M_TRIM_THRESHOLD, -1));
+  // Don't use mmap for large malloc chunks.
+  CHECK_EQ(1, mallopt(M_MMAP_MAX, 0));
+
+  if (&FLAGS_tcmalloc_release_rate) {
+    // Tell tcmalloc not to return memory.
+    FLAGS_tcmalloc_release_rate = 0.0;
+  }
+
+  // Forces the memory pages for all the stack space that we're ever going to
+  // use to be loaded into memory (so it can be locked there).
+  uint8_t data[4096 * 8];
+  // Not 0 because linux might optimize that to a 0-filled page.
+  memset(data, 1, sizeof(data));
+
+  static const size_t kHeapPreallocSize = 512 * 1024;
+  char *const heap_data = static_cast<char *>(malloc(kHeapPreallocSize));
+  memset(heap_data, 1, kHeapPreallocSize);
+  free(heap_data);
+}
+
+void InitRT() {
+  LockAllMemory();
+
+  // Only let rt processes run for 3 seconds straight.
+  SetSoftRLimit(RLIMIT_RTTIME, 3000000, true);
+
+  // Allow rt processes up to priority 40.
+  SetSoftRLimit(RLIMIT_RTPRIO, 40, false);
+}
+
+void UnsetCurrentThreadRealtimePriority() {
+  struct sched_param param;
+  param.sched_priority = 0;
+  PCHECK(sched_setscheduler(0, SCHED_OTHER, &param) == 0)
+      << ": sched_setscheduler(0, SCHED_OTHER, 0) failed";
+}
+
+void SetCurrentThreadName(const ::std::string &name) {
+  CHECK_LE(name.size(), 16u) << ": thread name '" << name << "' too long";
+  VLOG(1) << "This thread is changing to '" << name << "'";
+  PCHECK(prctl(PR_SET_NAME, name.c_str()) == 0);
+  if (&logging::internal::ReloadThreadName != nullptr) {
+    logging::internal::ReloadThreadName();
+  }
+}
+
+void SetCurrentThreadRealtimePriority(int priority) {
+  // Make sure we will only be allowed to run for 3 seconds straight.
+  SetSoftRLimit(RLIMIT_RTTIME, 3000000, true);
+
+  struct sched_param param;
+  param.sched_priority = priority;
+  PCHECK(sched_setscheduler(0, SCHED_FIFO, &param) == 0)
+      << ": sched_setscheduler(0, SCHED_FIFO, " << priority << ") failed";
+}
+
+void WriteCoreDumps() {
+  // Do create core files of unlimited size.
+  SetSoftRLimit(RLIMIT_CORE, RLIM_INFINITY, true);
+}
+
+}  // namespace aos