Function unmountAll

src/linux/fs.cpp:547–584

Try<Nothing> unmountAll(const string& target, int flags)
{
  Try<fs::MountTable> mountTable = fs::MountTable::read("/proc/mounts");
  if (mountTable.isError()) {
    return Error("Failed to read mount table: " + mountTable.error());
  }

  foreach (const MountTable::Entry& entry,
           adaptor::reverse(mountTable->entries)) {
    if (strings::startsWith(entry.dir, target)) {
      Try<Nothing> unmount = fs::unmount(entry.dir, flags);
      if (unmount.isError()) {
        return unmount;
      }

      // This normally should not fail even if the entry is not in
      // mtab or mtab doesn't exist or is not writable. However we
      // still catch the error here in case there's an error somewhere
      // else while running this command.
      // TODO(xujyan): Consider using `setmntent(3)` to implement this.
      const Option<int> status =
        os::spawn("umount", {"umount", "--fake", entry.dir});

      const string message =
        "Failed to clean up '" + entry.dir + "' in /etc/mtab";

      if (status.isNone()) {
        return ErrnoError(message);
      }

      if (!WSUCCEEDED(status.get())) {
        return Error(message + ": " + WSTRINGIFY(status.get()));
      }
    }
  }

  return Nothing();
}


Try<Nothing> pivot_root(