Zabbix

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** This program 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 Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

#include "async_telnet.h"

​

#include "zbxasyncpoller.h"

#include "zbxpoller.h"

#include "zbxtimekeeper.h"

#include "zbxcomms.h"

#include "zbxself.h"

​

ZBX_VECTOR_IMPL(telnet_recv, unsigned char)

​

static const char   *get_telnet_step_string(zbx_zabbix_telnet_step_t step)

{

    switch (step)

    {

        case ZABBIX_TELNET_STEP_CONNECT_INIT:

            return "init";

        case ZABBIX_TELNET_STEP_CONNECT_WAIT:

            return "connect";

        case ZABBIX_TELNET_STEP_SEND:

            return "send";

        case ZABBIX_TELNET_STEP_RECV:

            return "receive";

        default:

            return "unknown";

    }

}

​

static char telnet_lastchar(const char *buf, int offset)

{

    while (0 < offset)

    {

        offset--;

        if (' ' != buf[offset])

            return buf[offset];

    }

​

    return '\0';

}

​

static zbx_telnet_protocol_step_t   async_telnet_recv(zbx_telnet_context_t *telnet_context, short *events)

{

#define CMD_IAC     255

#define CMD_WILL    251

#define CMD_WONT    252

#define CMD_DO      253

#define CMD_DONT    254

#define OPT_SGA     3

​

    ssize_t         nbytes;

    zbx_socket_t        *s = &telnet_context->s;

    zbx_recv_context_t  *r = &telnet_context->recv_context;

​

    zabbix_log(LOG_LEVEL_DEBUG, "In %s():%u", __func__, r->state);

​

    if (ZABBIX_TELNET_PROTOCOL_SEND == r->state)

        r->state = ZABBIX_TELNET_PROTOCOL_RECV_FIRST;

​

    if (0 == r->buff.values_num)

        zbx_vector_telnet_recv_reserve(&r->buff, 255);

​

    do

    {

        switch (r->state)

        {

            case ZABBIX_TELNET_PROTOCOL_RECV_FIRST:

                if (1 > (nbytes = zbx_tcp_read(s, (char *)&r->c1, 1, events)))

                {

                    if (ZBX_PROTO_ERROR == nbytes && 0 == events)

                        r->state = ZABBIX_TELNET_PROTOCOL_RECV_FAIL;

​

                    break;

                }

​

                if (CMD_IAC != r->c1)

                {

                    zbx_vector_telnet_recv_append(&r->buff, r->c1);

                    break;