lbsmart
lbsmart

Reputation: 73

Boost socket acceptor segmentation fault

Im trying write tcp server. From boost guide link enter link description here. When im trying open acceptor - segmentation fault, IDE show me this line object_pool_access::prev(live_list_) = o; What im doing wrong? Im trying another way for example run threads for context but that doesnt work. Sometime when im try to fix i get this one message -

tpp.c:82: __pthread_tpp_change_priority: Assertion `new_prio == -1 || (new_prio >= fifo_min_prio && new_prio <= fifo_max_prio)' failed.
Aborted (core dumped)

The code is contained in the 1st file. Application class with io_context, he is here because ill use him in another parts of program:

#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <memory>

using namespace boost::asio;

class api_application
{
public:
    virtual ~api_application() {}

    virtual void start() = 0;
    virtual boost::asio::io_context& get_context() = 0;
};

class application : public api_application
{
public:
    application();
    ~application() override {}

public:
    virtual void start() override;
    virtual boost::asio::io_context& get_context() override;
    
    void stop();

private:
    boost::asio::io_context _context;

    std::shared_ptr<tcp_server> _server;
};


application::application()
:   
_context(),
_server(std::make_shared<tcp_server>(*this))
{}

void application::start()
{
    _server->start();
    _context.run();
}

void application::stop()
{
    _context.stop();
}

boost::asio::io_context& application::get_context()
{
    return _context;
}

Networking code with error line:

class connection : public std::enable_shared_from_this<connection>
{
public:
    typedef std::shared_ptr<connection> con_ptr;

    static con_ptr create(boost::asio::io_context& io_service)
    {
        return con_ptr(new connection(io_service));
    }

    ip::tcp::socket& socket();
    void send(std::string message);

private:
    connection(boost::asio::io_context& io_service);

    void handle_write(const boost::system::error_code& err, size_t s);

private:
    ip::tcp::socket _socket;
};

class tcp_server
{
public:
    tcp_server(api_application& app);

    void start();
private:
    void start_accept();
    void handle_accept(connection::con_ptr new_connection, const boost::system::error_code& error);

    api_application&   _app;
    ip::tcp::endpoint       _endpoint;
    ip::tcp::acceptor       _acceptor;
};


tcp_server::tcp_server(api_application& app)
:
_app(app), 
_endpoint(boost::asio::ip::address_v4::any(), 80),
_acceptor(app.get_context())
{}

void tcp_server::start()
{
    if(_acceptor.is_open())
        return;
    
    _acceptor.open(_endpoint.protocol()); // Here segfault
    _acceptor.set_option(ip::tcp::socket::reuse_address(true));
    
    _acceptor.bind(_endpoint);
    _acceptor.listen();
    start_accept();
}

void tcp_server::start_accept()
{
    connection::con_ptr new_connection =
    connection::create((boost::asio::io_context&)_acceptor.get_executor().context());

    _acceptor.async_accept(new_connection->socket(),
        boost::bind(&tcp_server::handle_accept, this, new_connection,
        boost::asio::placeholders::error));
}

void tcp_server::handle_accept(connection::con_ptr new_connection, const boost::system::error_code& error)
{
    if (!error)
    {
        new_connection->send("Success connection");
    }

    start_accept();
}

void connection::send(std::string message)
{
    boost::asio::async_write(_socket, boost::asio::buffer(message),
        boost::bind(&connection::handle_write, shared_from_this(),
        boost::asio::placeholders::error,
        boost::asio::placeholders::bytes_transferred));
}

connection::connection(boost::asio::io_context& io_service)
: _socket(io_service)
{}

int main(int argc, const char** argv)
{
    application app();
    app.start();
    return 0;
}

Upvotes: 1

Views: 178

Answers (1)

sehe
sehe

Reputation: 393134

I found the likely issue while rewriting the code to avoid context references. See Update

I have no problem with the code, imagining the missing bits:

Live On Coliru

#include <boost/asio.hpp>
#include <boost/bind/bind.hpp>
#include <iostream>
#include <memory>

namespace asio = boost::asio;
using asio::ip::tcp;
using boost::system::error_code;

class connection : public std::enable_shared_from_this<connection> {
  public:
    typedef std::shared_ptr<connection> con_ptr;

    static con_ptr create(asio::io_context& io_service) {
        return con_ptr{new connection(io_service)};
    }

    tcp::socket& socket() { return _socket; }
    void         send(std::string message);

  private:
    connection(asio::io_context& io_service);

    void handle_write(error_code err, size_t s) {
        std::cerr << "handle_write: " << err.message() << " " << s << std::endl;
    }

  private:
    tcp::socket _socket;
};

struct api_application {
    virtual ~api_application() {}
    virtual void              start()       = 0;
    virtual asio::io_context& get_context() = 0;
};

class tcp_server {
  public:
    tcp_server(api_application& app);

    void start();

  private:
    void start_accept();
    void handle_accept(connection::con_ptr new_connection,
                       error_code          error);

    api_application& _app;
    tcp::endpoint    _endpoint;
    tcp::acceptor    _acceptor;
};

class application : public api_application {
  public:
    application();
    ~application() override {}

  public:
    virtual void              start() override;
    virtual asio::io_context& get_context() override;

    void stop();

  private:
    asio::io_context _context;

    std::shared_ptr<tcp_server> _server;
};

application::application()
    : _context()
    , _server(std::make_shared<tcp_server>(*this)) {}

void application::start() {
    _server->start();
    _context.run();
}

tcp_server::tcp_server(api_application& app)
    : _app(app)
    , _endpoint({}, 8989)
    , _acceptor(app.get_context()) {}

void tcp_server::start() {
    if (_acceptor.is_open())
        return;

    _acceptor.open(_endpoint.protocol()); // Here segfault
    _acceptor.set_option(tcp::acceptor::reuse_address(true));

    _acceptor.bind(_endpoint);
    _acceptor.listen();
    start_accept();
}

void tcp_server::start_accept() {
    connection::con_ptr new_connection = connection::create(
        (asio::io_context&)_acceptor.get_executor().context());

    _acceptor.async_accept(new_connection->socket(),
                           boost::bind(&tcp_server::handle_accept, this,
                                       new_connection,
                                       asio::placeholders::error));
}

void tcp_server::handle_accept(connection::con_ptr new_connection,
                               error_code          error) {
    if (!error) {
        new_connection->send("Success connection");
    }

    start_accept();
}

void connection::send(std::string message) {
    async_write(_socket, asio::buffer(message),
                boost::bind(&connection::handle_write,
                            shared_from_this(),
                            asio::placeholders::error,
                            asio::placeholders::bytes_transferred));
}

connection::connection(asio::io_context& io_service)
    : _socket(io_service) {}

void application::stop() { _context.stop(); }

asio::io_context& application::get_context() { return _context; }

int main() {
    application app;
    app.start();
}

Prints e.g.

g++ -std=c++20 -O2 -Wall -pedantic -pthread main.cpp
./a.out&
for a in {1..10}; do sleep 0.5; nc 127.0.0.1 8989 <<<"Hello world"; done
kill %1
Success connectionhandle_write: Success 18
handle_write: Success connectionSuccess 18
handle_write: Success Success connection18
Success connectionhandle_write: Success 18
Success connectionhandle_write: Success 18
Success connectionhandle_write: Success 18
Success connectionhandle_write: Success 18
Success connectionhandle_write: Success 18
Success connectionhandle_write: Success 18
Success connectionhandle_write: Success 18

Summary

Your problem is elsewhere. Permissions, exception handling, ODR, maybe you're not running the code you think you are.

Also, this code seems unnecessarily complicated and a bit dated (io_service has been deprecated for quite some time).

UPDATE

This is highly suspicious code

connection::con_ptr new_connection = connection::create( (asio::io_context&)_acceptor.get_executor().context());

If it works it is due to undocumented implementation details. It is technically Undefined Behaviour because it does a hard re-interpret-cast. Instead, just use the executor as intended!

auto new_connection = connection::create(_acceptor.get_executor());

Here's the whole thing reworked to avoid context references:

#include <boost/asio.hpp>
#include <boost/bind/bind.hpp>
#include <iostream>
#include <memory>

namespace asio = boost::asio;
using asio::ip::tcp;
using boost::system::error_code;

class connection : public std::enable_shared_from_this<connection> {
  public:
    typedef std::shared_ptr<connection> con_ptr;

    static con_ptr create(asio::any_io_executor ex) {
        return con_ptr{new connection(ex)};
    }

    tcp::socket& socket() { return _socket; }
    void         send(std::string message);

  private:
    connection(asio::any_io_executor ex);

    void handle_write(error_code err, size_t s) {
        std::cerr << "handle_write: " << err.message() << " " << s << std::endl;
    }

  private:
    tcp::socket _socket;
};

struct api_application {
    virtual ~api_application() {}
    virtual void                  start()        = 0;
    virtual asio::any_io_executor get_executor() = 0;
};

class tcp_server {
  public:
    tcp_server(api_application& app);

    void start();

  private:
    void start_accept();
    void handle_accept(connection::con_ptr new_connection,
                       error_code          error);

    api_application& _app;
    tcp::endpoint    _endpoint;
    tcp::acceptor    _acceptor;
};

class application : public api_application {
  public:
    application();
    ~application() override {}

  public:
    virtual void                  start() override;
    virtual asio::any_io_executor get_executor() override;

    void stop();

  private:
    asio::io_context _context;

    std::shared_ptr<tcp_server> _server;
};

application::application()
    : _context()
    , _server(std::make_shared<tcp_server>(*this)) {}

void application::start() {
    _server->start();
    _context.run();
}

tcp_server::tcp_server(api_application& app)
    : _app(app)
    , _endpoint({}, 8989)
    , _acceptor(app.get_executor()) {}

void tcp_server::start() {
    if (_acceptor.is_open())
        return;

    _acceptor.open(_endpoint.protocol()); // Here segfault
    _acceptor.set_option(tcp::acceptor::reuse_address(true));

    _acceptor.bind(_endpoint);
    _acceptor.listen();
    start_accept();
}

void tcp_server::start_accept() {
    auto new_connection = connection::create(_acceptor.get_executor());

    _acceptor.async_accept(new_connection->socket(),
                           boost::bind(&tcp_server::handle_accept, this,
                                       new_connection,
                                       asio::placeholders::error));
}

void tcp_server::handle_accept(connection::con_ptr new_connection,
                               error_code          error) {
    if (!error) {
        new_connection->send("Success connection");
    }

    start_accept();
}

void connection::send(std::string message) {
    async_write(_socket, asio::buffer(message),
                boost::bind(&connection::handle_write,
                            shared_from_this(),
                            asio::placeholders::error,
                            asio::placeholders::bytes_transferred));
}

connection::connection(asio::any_io_executor ex) : _socket(ex) {}

void application::stop() { _context.stop(); }
asio::any_io_executor application::get_executor() {
    return _context.get_executor();
}

int main() {
    application app;
    app.start();
}

Still printing the same Live On Coliru

Upvotes: 1

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