Function getParentShmPath

src/slave/containerizer/mesos/paths.cpp:538–597

Try<string> getParentShmPath(
    const string runtimeDir,
    const ContainerID& containerId)
{
  CHECK(containerId.has_parent());

  ContainerID parentId = containerId.parent();

  Result<ContainerConfig> parentConfig =
    getContainerConfig(runtimeDir, parentId);

  if (parentConfig.isNone()) {
    return Error(
        "Failed to find config for container " + stringify(parentId));
  } else if (parentConfig.isError()) {
    return Error(parentConfig.error());
  }

  string parentShmPath;

  if (parentConfig->has_container_info() &&
      parentConfig->container_info().has_linux_info() &&
      parentConfig->container_info().linux_info().has_ipc_mode()) {
    switch (parentConfig->container_info().linux_info().ipc_mode()) {
      case LinuxInfo::PRIVATE: {
        const string shmPath = getContainerShmPath(runtimeDir, parentId);
        if (!os::exists(shmPath)) {
          return Error(
              "The shared memory path '" + shmPath + "' of container "
              + stringify(parentId) + " does not exist");
        }

        parentShmPath = shmPath;
        break;
      }
      case LinuxInfo::SHARE_PARENT: {
        if (parentId.has_parent()) {
          return getParentShmPath(runtimeDir, parentId);
        }

        parentShmPath = AGENT_SHM_DIRECTORY;
        break;
      }
      case LinuxInfo::UNKNOWN: {
        LOG(FATAL) << "The IPC mode of container " << parentId << " is UNKNOWN";
      }
    }
  } else {
    if (parentConfig->has_rootfs()) {
      return Error(
          "The shared memory of container " + stringify(parentId) +
          " cannot be shared with any other containers because it"
          " is only in the container's own mount namespace");
    }

    parentShmPath = AGENT_SHM_DIRECTORY;
  }