libt2n: (gerd) more documentation-polishing

[libt2n] / src / socket_client.cpp

/***************************************************************************
 *   Copyright (C) 2006 by Gerd v. Egidy                                   *
 *   gve@intra2net.com                                                     *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Lesser General Public License version   *
 *   2.1 as published by the Free Software Foundation.                     *
 *                                                                         *
 *   This library is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU Lesser General Public License for more details.                   *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this program; if not, write to the                 *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netdb.h>
#include <fcntl.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>

#include <sstream>

#include "socket_client.hxx"
#include "t2n_exception.hxx"
#include "log.hxx"

using namespace std;

namespace libt2n
{

/// returns a closed connection if connection could not be established, call get_last_error_msg() for details
socket_client_connection::socket_client_connection(int _port, const std::string& _server, 
            long long _connect_timeout_usec, int _max_retries,
            std::ostream *_logstream, log_level_values _log_level)
    : client_connection(), socket_handler(0,tcp_s)
{
    max_retries=_max_retries;
    connect_timeout_usec=_connect_timeout_usec;

    server=_server;
    port=_port;

    set_logging(_logstream,_log_level);

    try
    {
        tcp_connect(max_retries);
    }
    catch (t2n_communication_error &e)
    {
        lastErrorMsg=e.what();
        LOGSTREAM(debug,"tcp connect error: " << lastErrorMsg);
        close();
    }

    if (!connection::is_closed())
        do_callbacks(new_connection);
}

/// returns a closed connection if connection could not be established, call get_last_error_msg() for details
socket_client_connection::socket_client_connection(const std::string& _path,
            long long _connect_timeout_usec, int _max_retries,
            std::ostream *_logstream, log_level_values _log_level)
    : client_connection(), socket_handler(0,unix_s)
{
    max_retries=_max_retries;
    connect_timeout_usec=_connect_timeout_usec;

    path=_path;

    set_logging(_logstream,_log_level);

    try
    {
        unix_connect(max_retries);
    }
    catch (t2n_communication_error &e)
    {
        lastErrorMsg=e.what();
        LOGSTREAM(debug,"unix connect error: " << lastErrorMsg);
        close();
    }

    if (!connection::is_closed())
        do_callbacks(new_connection);
}

/// establish a connection via tcp
void socket_client_connection::tcp_connect(int max_retries)
{
    struct sockaddr_in sock_addr;

    sock_addr.sin_family = AF_INET;
    sock_addr.sin_port = htons(port);

    // find the target ip
    if (inet_aton(server.c_str(),&sock_addr.sin_addr)==0)
    {
        struct hostent *server_hent;
        server_hent=gethostbyname(server.c_str());
        if (server_hent == NULL)
            throw t2n_connect_error(string("can't find server ")+server);

        memcpy(&sock_addr.sin_addr,server_hent->h_addr_list[0],sizeof(sock_addr.sin_addr));
    }

    sock = socket(PF_INET, SOCK_STREAM, 0);
    if (!sock)
        throw t2n_connect_error(string("socket() error: ")+strerror(errno));

    try
    {
        connect_with_timeout((struct sockaddr *) &sock_addr,sizeof(sock_addr));
    }
    catch (t2n_connect_error &e)
    {
        // recurse if retries left
        if (max_retries > 0)
        {
            LOGSTREAM(debug,"retrying connect after connect error");
            tcp_connect(max_retries-1);
        }
        else
            throw t2n_connect_error("no more retries left after connect error");
    }
}

/// establish a connection via unix-socket
void socket_client_connection::unix_connect(int max_retries)
{
    struct sockaddr_un unix_addr;

    unix_addr.sun_family = AF_UNIX;
    strcpy (unix_addr.sun_path, path.c_str());

    sock = socket(PF_UNIX, SOCK_STREAM, 0);
    if (!sock)
        throw t2n_connect_error(string("socket() error: ")+strerror(errno));

    try
    {
        connect_with_timeout((struct sockaddr *) &unix_addr, sizeof(unix_addr));
    }
    catch (t2n_connect_error &e)
    {
        // recurse if retries left
        if (max_retries > 0)
        {
            LOGSTREAM(debug,"retrying connect after connect error");
            unix_connect(max_retries-1);
        }
        else
            throw t2n_connect_error("no more retries left after connect error");
    }
}

/// execute a connect on a prepared socket (tcp or unix) respecting timeouts
void socket_client_connection::connect_with_timeout(struct sockaddr *sock_addr,unsigned int sockaddr_size)
{
    set_socket_options(sock);

    LOGSTREAM(debug,"connect_with_timeout()");
    int ret=::connect(sock,sock_addr, sockaddr_size);

    if (ret < 0)
    {
        if (errno==EINPROGRESS)
        {
            LOGSTREAM(debug,"connect_with_timeout(): EINPROGRESS");

            /* set timeout */
            struct timeval tval;
            struct timeval *timeout_ptr;

            if (connect_timeout_usec == -1)
                timeout_ptr = NULL;
            else
            {
                timeout_ptr = &tval;

                // convert timeout from long long usec to int sec + int usec
                tval.tv_sec = connect_timeout_usec / 1000000;
                tval.tv_usec = connect_timeout_usec % 1000000;
            }

            fd_set connect_socket_set;
            FD_ZERO(&connect_socket_set);
            FD_SET(sock,&connect_socket_set);

            int ret;
            while ((ret=select(FD_SETSIZE, NULL, &connect_socket_set, NULL, timeout_ptr)) &&
                    ret < 0 && errno==EINTR);

            if (ret < 0)
                throw t2n_connect_error(string("connect() error (select): ")+strerror(errno));

            socklen_t sopt=sizeof(int);
            int valopt;
            ret=getsockopt(sock, SOL_SOCKET, SO_ERROR, (void*)(&valopt), &sopt);
            if (ret < 0 || valopt)
                throw t2n_connect_error(string("connect() error (getsockopt): ")+strerror(errno));
        }
        else
            throw t2n_connect_error(string("connect() error: ")+strerror(errno));
    }

    LOGSTREAM(debug,"connect_with_timeout(): success");
}

void socket_client_connection::close()
{
    if (!client_connection::is_closed())
    {
        socket_handler::close();
        client_connection::close();
    }
}

/** @brief try to reconnect the current connection with the same connection credentials (host and port or path)

    @note will throw an exeption if reconnecting not possible
*/
void socket_client_connection::reconnect()
{
    LOGSTREAM(debug,"reconnect()");

    // close the current connection if still open
    close();

    socket_type_value type=get_type();

    if (type == tcp_s)
        tcp_connect(max_retries);
    else if (type == unix_s)
        unix_connect(max_retries);

    // connection is open now, otherwise an execption would have been thrown
    reopen();

    LOGSTREAM(debug,"reconnect() done, client_connection::is_closed() now " << client_connection::is_closed());
}

}