ttynvt/nvtsrv/nvtsrv.c

/*
 * RFC2217 test server
 */
#include <poll.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "lib/nvt_log.h"
#include "lib/nvt_socket.h"
#include "telnet.h"


/**INDENT-OFF**/
static const char help_text[] =
    "Usage: nvtsrv OPTIONS... HOST:PORT\n"
    "OPTIONS:\n"
    "  -d         : Enable debug\n"
    "  -e         : Echo received data\n"
    "  -q         : Quiet\n"
    ;
/**INDENT-ON**/

struct {
    unsigned char   mline;
    tn_ctx_t       *tnct;
} dd;

struct pollfd   pfds[3];
int             nfds;

#define fd_srv pfds[1].fd
#define fd_cli pfds[2].fd


static void _usage(int rc)
{
    printf(help_text);
    exit(rc);
}

static void _tn_cli_close(void)
{
    int             i = 2;

    nvt_log(LOG_INFO, "%d: fd=%d: Closed\n", i, pfds[i].fd);
    close(pfds[i].fd);
    pfds[i].fd = -1;
    nfds = 2;
}

static void _tn_tx(void *cctx, const void *buf, int len)
{
    int             nw;

    DBG2_BUF("Tx", buf, len);

    if (fd_cli < 0)
    {
        nvt_log(LOG_NOTICE, "Write fd is closed - drop Tx\n");
        return;
    }

    nw = write(fd_cli, buf, len);
    if (nw != len)
    {
        nvt_log(LOG_ERR, "Write failed %d != %d\n", nw, len);
        _tn_cli_close();
    }
}

static void _tn_ss(void *cctx, int signal, int value)
{
    DBG("RFC2217 signal %d: %02x", signal, value);
}

static void _nvtsrv_init(void)
{
    free(dd.tnct);

    memset(&dd, 0, sizeof(dd));

    dd.tnct = telnet_ctx_init(NULL, _tn_tx, _tn_ss);
}

static void _nvtsrv_cmd(tn_ctx_t *tcc, const char *line, int len)
{
    int             val;

    if (line[0] == '*' && len > 2)
    {
        /* Special features */
        if (line[1] == 'm')
        {
            sscanf(line + 2, "%x", &val);
            telnet_rfc2217_change_modemstate(tcc, val);
        }
    }
    else
    {
        /* Send all input */
        _tn_tx(NULL, line, len);
    }
}

static void _nvtsrv_set_signal_handlers(void)
{
    struct sigaction sa = {
        .sa_handler = SIG_IGN,
        .sa_flags = SA_RESTART,
    };

    sigemptyset(&sa.sa_mask);
    sigaction(SIGPIPE, &sa, NULL);
}

int main(int argc, char **argv)
{
    int             opt;
    char            buf[128];
    int             rc, nr, i, len;
    int             debug, quiet;
    bool            do_echo;

    debug = quiet = 0;
    do_echo = false;

    while ((opt = getopt(argc, argv, "deq")) != -1)
    {
        switch (opt)
        {
        default:               /* '?' */
            _usage(0);
            break;
        case 'd':
            debug += 1;
            break;
        case 'e':              /* Echo received data */
            do_echo = true;
            break;
        case 'q':
            quiet = 1;
            break;
        }
    }

    argc -= optind;
    argv += optind;
    if (argc <= 0)
        _usage(1);

    nvt_log_level(quiet, debug);
    nvt_log_dest(NVT_LOG_STDOUT);

    _nvtsrv_set_signal_handlers();

    memset(pfds, 0, sizeof(pfds));

    pfds[0].fd = STDIN_FILENO;
    pfds[0].events = POLLIN;

    pfds[1].fd = socket_create_server(argv[0]);
    pfds[1].events = POLLIN;

    pfds[2].fd = -1;
    pfds[2].events = POLLIN;

    nfds = 2;

    for (;;)
    {
        for (i = 0; i < 3; i++)
            pfds[i].revents = 0;

        rc = poll(pfds, nfds, -1);
        if (rc < 0)
        {
            nvt_log(LOG_ERR, "poll failed: %m\n");
            break;
        }

        i = 0;
        if (pfds[i].revents)
        {
            nr = read(pfds[i].fd, buf, sizeof(buf) - 1);
            if (nr <= 0)
                break;
            buf[nr] = 0;
            DBG2_BUF("Con Rx", buf, nr);
            _nvtsrv_cmd(dd.tnct, buf, nr);
        }

        i = 2;
        if (pfds[i].revents)
        {
            nr = 0;
            if (pfds[i].revents & POLLIN)
            {
                nr = read(pfds[i].fd, buf, sizeof(buf));
                if (nr <= 0)
                {
                    _tn_cli_close();
                    continue;
                }
            }
            if (pfds[i].revents & (POLLERR | POLLHUP))
            {
                _tn_cli_close();
            }

            if (nr > 0)
            {
                buf[nr] = 0;
                DBG2_BUF("Rx", buf, nr);
                len = nr;
                rc = telnet_rx(dd.tnct, buf, &len);
                if (do_echo)
                {
                    /* Echo received */
                    _tn_tx(NULL, buf, len);
                }
            }
        }

        i = 1;
        if (pfds[i].revents)
        {
            if (pfds[2].fd >= 0)
            {
                nvt_log(LOG_NOTICE, "Client already connected on fd=%d\n",
                        pfds[2].fd);
                break;
            }
            pfds[2].fd = socket_create_server_client(pfds[i].fd);
            nvt_log(LOG_INFO, "%d: fd=%d: Connected\n", 2, pfds[2].fd);
            pfds[2].events = POLLIN;
            nfds = 3;
            _nvtsrv_init();
        }
    }

    return 0;
}