Function setns

src/linux/ns.cpp:165–214

Try<Nothing> setns(
    const string& path,
    const string& ns,
    bool checkMultithreaded)
{
  if (checkMultithreaded) {
    // Return error if there're multiple threads in the calling process.
    Try<set<pid_t>> threads = proc::threads(::getpid());
    if (threads.isError()) {
      return Error(
          "Failed to get the threads of the current process: " +
          threads.error());
    } else if (threads->size() > 1) {
      return Error("Multiple threads exist in the current process");
    }
  }

  if (ns::namespaces().count(ns) == 0) {
    return Error("Namespace '" + ns + "' is not supported");
  }

  // Currently, we don't support pid namespace as its semantics is
  // different from other namespaces (instead of re-associating the
  // calling thread, it re-associates the *children* of the calling
  // thread with the specified namespace).
  if (ns == "pid") {
    return Error("Pid namespace is not supported");
  }

  Try<int> fd = os::open(path, O_RDONLY | O_CLOEXEC);

  if (fd.isError()) {
    return Error("Failed to open '" + path + "': " + fd.error());
  }

  Try<int> nstype = ns::nstype(ns);
  if (nstype.isError()) {
    return Error(nstype.error());
  }

  if (::setns(fd.get(), nstype.get()) == -1) {
    // Save the errno as it might be overwritten by 'os::close' below.
    ErrnoError error;
    os::close(fd.get());
    return error;
  }

  os::close(fd.get());
  return Nothing();
}


Try<Nothing> setns(pid_t pid, const string& ns, bool checkMultithreaded)