libc/system_properties/context_node.h

/*
 * Copyright (C) 2008 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef SYSTEM_PROPERTIES_CONTEXT_NODE_H
#define SYSTEM_PROPERTIES_CONTEXT_NODE_H

#include "private/bionic_lock.h"

#include "prop_area.h"

class ContextNode {
 public:
  ContextNode(const char* context) : context_(context), pa_(nullptr), no_access_(false) {
    lock_.init(false);
  }
  ~ContextNode() {
    Unmap();
  }

  ContextNode(const ContextNode&) = delete;
  ContextNode(ContextNode&&) = delete;
  void operator=(const ContextNode&) = delete;
  void operator=(const ContextNode&&) = delete;

  bool Open(bool access_rw, bool* fsetxattr_failed);
  bool CheckAccessAndOpen();
  void ResetAccess();
  void Unmap();

  const char* context() const {
    return context_;
  }
  prop_area* pa() {
    return pa_;
  }

 private:
  bool CheckAccess();

  Lock lock_;
  const char* context_;
  prop_area* pa_;
  bool no_access_;
};

#endif