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/ipc_lib/shared_mem.cc b/aos/ipc_lib/shared_mem.cc
new file mode 100644
index 0000000..93ced7d
--- /dev/null
+++ b/aos/ipc_lib/shared_mem.cc
@@ -0,0 +1,138 @@
+#include "aos/ipc_lib/shared_mem.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "aos/ipc_lib/aos_sync.h"
+#include "aos/ipc_lib/core_lib.h"
+#include "glog/logging.h"
+
+// the path for the shared memory segment. see shm_open(3) for restrictions
+#define AOS_SHM_NAME "/aos_shared_mem"
+// Size of the shared mem segment.
+// This must fit in the tmpfs for /dev/shm/
+#define SIZEOFSHMSEG (4096 * 0x3000)
+
+void init_shared_mem_core(aos_shm_core *shm_core) {
+  memset(&shm_core->time_offset, 0 , sizeof(shm_core->time_offset));
+  memset(&shm_core->msg_alloc_lock, 0, sizeof(shm_core->msg_alloc_lock));
+  shm_core->queues.pointer = NULL;
+  memset(&shm_core->queues.lock, 0, sizeof(shm_core->queues.lock));
+  shm_core->queue_types.pointer = NULL;
+  memset(&shm_core->queue_types.lock, 0, sizeof(shm_core->queue_types.lock));
+}
+
+ptrdiff_t aos_core_get_mem_usage(void) {
+  return global_core->size -
+      ((ptrdiff_t)global_core->mem_struct->msg_alloc -
+       (ptrdiff_t)global_core->mem_struct);
+}
+
+struct aos_core *global_core = NULL;
+
+// TODO(brians): madvise(2) it to put this shm in core dumps.
+void aos_core_create_shared_mem(int create, int lock) {
+  assert(global_core == NULL);
+  static struct aos_core global_core_data;
+  global_core = &global_core_data;
+
+  {
+    char *shm_name = getenv("AOS_SHM_NAME");
+    if (shm_name == NULL) {
+      global_core->shm_name = AOS_SHM_NAME;
+    } else {
+      printf("AOS_SHM_NAME defined, using %s\n", shm_name);
+      global_core->shm_name = shm_name;
+    }
+  }
+
+  int shm;
+  if (create) {
+    while (1) {
+      shm = shm_open(global_core->shm_name, O_RDWR | O_CREAT | O_EXCL, 0666);
+      global_core->owner = 1;
+      if (shm == -1 && errno == EEXIST) {
+        printf("shared_mem: going to shm_unlink(%s)\n", global_core->shm_name);
+        if (shm_unlink(global_core->shm_name) == -1) {
+          PLOG(WARNING) << "shm_unlink(" << global_core->shm_name << ") failed";
+          break;
+        }
+      } else {
+        break;
+      }
+    }
+  } else {
+    shm = shm_open(global_core->shm_name, O_RDWR, 0);
+    global_core->owner = 0;
+  }
+  if (shm == -1) {
+    PLOG(FATAL) << "shm_open(" << global_core->shm_name
+                << ", O_RDWR [| O_CREAT | O_EXCL, 0|0666) failed";
+  }
+  if (global_core->owner) {
+    PCHECK(ftruncate(shm, SIZEOFSHMSEG) == 0)
+        << ": fruncate(" << shm << ", 0x" << std::hex << (size_t)SIZEOFSHMSEG
+        << ") failed";
+  }
+  int flags = MAP_SHARED | MAP_FIXED;
+  if (lock) flags |= MAP_LOCKED | MAP_POPULATE;
+  void *shm_address = mmap((void *)SHM_START, SIZEOFSHMSEG,
+                           PROT_READ | PROT_WRITE, flags, shm, 0);
+  PCHECK(shm_address != MAP_FAILED)
+      << std::hex << "shared_mem: mmap(" << (void *)SHM_START << ", 0x"
+      << (size_t)SIZEOFSHMSEG << ", stuff, " << flags << ", " << shm
+      << ", 0) failed";
+  if (create) {
+    printf("shared_mem: creating %s, shm at: %p\n", global_core->shm_name,
+           shm_address);
+  } else {
+    printf("shared_mem: not creating, shm at: %p\n", shm_address);
+  }
+  if (close(shm) == -1) {
+    PLOG(WARNING) << "close(" << shm << "(=shm) failed";
+  }
+  PCHECK(shm_address == (void *)SHM_START)
+      << "shm isn't at hard-coded " << (void *)SHM_START << ". at "
+      << shm_address << " instead";
+  aos_core_use_address_as_shared_mem(shm_address, SIZEOFSHMSEG);
+  LOG(INFO) << "shared_mem: end of create_shared_mem owner="
+            << global_core->owner;
+}
+
+void aos_core_use_address_as_shared_mem(void *address, size_t size) {
+  global_core->mem_struct = reinterpret_cast<aos_shm_core_t *>(address);
+  global_core->size = size;
+  global_core->shared_mem =
+      (uint8_t *)address + sizeof(*global_core->mem_struct);
+  if (global_core->owner) {
+    global_core->mem_struct->msg_alloc = (uint8_t *)address + global_core->size;
+    init_shared_mem_core(global_core->mem_struct);
+    futex_set(&global_core->mem_struct->creation_condition);
+  } else {
+    if (futex_wait(&global_core->mem_struct->creation_condition) != 0) {
+      LOG(FATAL) << "waiting on creation_condition failed";
+    }
+  }
+}
+
+void aos_core_free_shared_mem() {
+  void *shm_address = global_core->shared_mem;
+  PCHECK(munmap((void *)SHM_START, SIZEOFSHMSEG) != -1)
+      << ": munmap(" << shm_address << ", 0x" << std::hex
+      << (size_t)SIZEOFSHMSEG << ") failed";
+  if (global_core->owner) {
+    PCHECK(shm_unlink(global_core->shm_name) == 0)
+        << ": shared_mem: shm_unlink(" << global_core->shm_name << ") failed";
+  }
+}
+
+int aos_core_is_init(void) {
+  return global_core != NULL;
+}