/*
 * Copyright (c) 2002-2005 The Regents of The University of Michigan
 * 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;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * 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 __SOCKET_HH__
#define __SOCKET_HH__

#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>

#include <cassert>
#include <functional>
#include <memory>
#include <string>

#include "base/named.hh"

namespace gem5
{

class ListenSocket : public Named
{
  protected:
    /**
     * The following variables are only used by socket unit tests:
     * listeningDisabled, anyListening, bindToLoopback.
     */
    static bool listeningDisabled;
    static bool anyListening;

    static bool bindToLoopback;

  public:
    static void disableAll();
    static bool allDisabled();

    static void loopbackOnly();

  protected:
    bool listening = false;
    int fd = -1;

    void
    setListening()
    {
        listening = true;
        anyListening = true;
    }

    /*
     * cleanup resets the static variables back to their default values.
     */
    static void cleanup();

    ListenSocket(const std::string &_name);

  public:
    /**
     * @ingroup api_socket
     * @{
     */
    virtual ~ListenSocket();

    virtual int accept();
    virtual void listen() = 0;

    virtual void output(std::ostream &os) const = 0;

    int getfd() const { return fd; }
    bool islistening() const { return listening; }

    /* Create a socket, adding SOCK_CLOEXEC if available. */
    static int socketCloexec(int domain, int type, int protocol);
    /* Accept a connection, adding SOCK_CLOEXEC if available. */
    static int acceptCloexec(int sockfd, struct sockaddr *addr,
                              socklen_t *addrlen);
    /** @} */ // end of api_socket
};

inline static std::ostream &
operator << (std::ostream &os, const ListenSocket &socket)
{
    socket.output(os);
    return os;
}

using ListenSocketPtr = std::unique_ptr<ListenSocket>;

class ListenSocketConfig
{
  public:
    using Builder = std::function<ListenSocketPtr(const std::string &name)>;

    ListenSocketConfig() {}
    ListenSocketConfig(Builder _builder) : builder(_builder) {}

    ListenSocketPtr
    build(const std::string &name) const
    {
        assert(builder);
        return builder(name);
    }

    operator bool() const { return (bool)builder; }

    static bool parseIni(const std::string &value, ListenSocketConfig &retval);

  private:
    Builder builder;
};

static inline ListenSocketConfig listenSocketEmptyConfig() { return {}; }

// AF_INET based sockets.

class ListenSocketInet : public ListenSocket
{
  protected:
    int _port;

    virtual bool listen(int port);

  public:
    ListenSocketInet(const std::string &_name, int port);

    int accept() override;
    void listen() override;
    void output(std::ostream &os) const override;
};

ListenSocketConfig listenSocketInetConfig(int port);

// AF_UNIX based sockets.

class ListenSocketUnix : public ListenSocket
{
  protected:
    virtual size_t prepSockaddrUn(sockaddr_un &addr) const = 0;

    void checkPathLength(const std::string &original, size_t max_len);

    ListenSocketUnix(const std::string &_name) : ListenSocket(_name) {}

  public:
    void listen() override;
};

class ListenSocketUnixFile : public ListenSocketUnix
{
  protected:
    std::string dir;
    std::string resolvedDir;
    std::string fname;

    bool unlink() const;

    size_t prepSockaddrUn(sockaddr_un &addr) const override;

  public:
    ListenSocketUnixFile(const std::string &_name, const std::string &_dir,
            const std::string &_fname);
    ~ListenSocketUnixFile();

    void listen() override;
    void output(std::ostream &os) const override;
};

ListenSocketConfig listenSocketUnixFileConfig(
        std::string dir, std::string fname);

class ListenSocketUnixAbstract : public ListenSocketUnix
{
  protected:
    std::string path;

    size_t prepSockaddrUn(sockaddr_un &addr) const override;

  public:
    ListenSocketUnixAbstract(
            const std::string &_name, const std::string &_path);

    void output(std::ostream &os) const override;
};

ListenSocketConfig listenSocketUnixAbstractConfig(std::string path);

} // namespace gem5

#endif //__SOCKET_HH__