/**
 * xrdp: A Remote Desktop Protocol server.
 *
 * Copyright (C) Jay Sorg 2004-2023
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 *
 * @file ercp_server.c
 * @brief ercp (executive run-time control protocol) server function
 * @author Matt Burt
 *
 */

#if defined(HAVE_CONFIG_H)
#include <config_ac.h>
#endif

#include "arch.h"

#include "login_info.h"
#include "scp.h"
#include "sesexec.h"
#include "os_calls.h"
#include "session.h"
#include "trans.h"

#include "ercp.h"
#include "ercp_server.h"

/******************************************************************************/
static enum scp_sconnect_status
get_session_fds(struct session_data *sd, unsigned int scp_flags,
                int *display_fd, int *chan_fd)
{
    enum scp_sconnect_status result = E_SCP_SCONNECT_OK;

    if ((*display_fd = session_get_display_server_fd(g_login_info, sd)) < 0)
    {
        result = E_SCP_SCONNECT_SERVER_FAIL;
    }
    else if ((scp_flags & E_SCP_SCONNECT_FLAG_NEED_CHANSRV) == 0)
    {
        // Don't need to try to connect to chansrv
        *chan_fd = -1;
    }
    else
    {
        // If this fails, it's inconvenient, but not a show-stopper
        *chan_fd = session_get_chansrv_fd(g_login_info, sd);
    }

    return result;
}

/******************************************************************************/
static int
handle_connect_session_request(struct trans *self)
{
    int scp_fd = -1;
    unsigned int scp_flags;

    int rv = ercp_get_connect_session_request(self, &scp_fd, &scp_flags);
    if (rv == 0)
    {
        struct trans *scp_trans;

        if ((scp_trans = scp_init_trans_from_fd(scp_fd,
                                                TRANS_TYPE_SERVER,
                                                sesexec_is_term)) == NULL)
        {
            LOG(LOG_LEVEL_ERROR, "Can't create SCP trans");
            rv = 1;
        }
        else
        {
            scp_fd = -1; // Don't close this twice!

            // Now we've got a transport we can send data back to
            // the SCP client
            enum scp_sconnect_status scp_status;
            int display_fd = -1;
            int chan_fd = -1;
            scp_status = get_session_fds(g_session_data, scp_flags,
                                         &display_fd, &chan_fd);
            rv = scp_send_connect_session_response(scp_trans, scp_status,
                                                   display_fd, chan_fd);

            if (rv == 0 && scp_status == E_SCP_SCONNECT_OK)
            {
                // Don't run the reconnect script on the first connect
                if (session_increment_connect_count(g_session_data) == 0)
                {
                    LOG(LOG_LEVEL_INFO, "User %s has connected to a session",
                        g_login_info->username);
                }
                else
                {
                    LOG(LOG_LEVEL_INFO, "User %s has reconnected to a session",
                        g_login_info->username);
                    session_run_reconnect_script(g_login_info, g_session_data);
                }
            }

            // Regardless of the result of the send, we must close all
            // our copies of file descriptors.
            if (display_fd >= 0)
            {
                g_file_close(display_fd);
            }
            if (chan_fd >= 0)
            {
                g_file_close(chan_fd);
            }
            trans_delete(scp_trans);
        }
    }

    if (scp_fd >= 0)
    {
        g_file_close(scp_fd);
    }

    return rv;
}

/******************************************************************************/
int
ercp_server(struct trans *self)
{
    int rv = 0;
    enum ercp_msg_code msgno;

    switch ((msgno = ercp_msg_in_get_msgno(self)))
    {
        case E_ERCP_CONNECT_SESSION_REQUEST:
            rv = handle_connect_session_request(self);
            break;

        default:
        {
            char buff[64];
            ercp_msgno_to_str(msgno, buff, sizeof(buff));
            LOG(LOG_LEVEL_ERROR, "Ignored ERCP message %s", buff);
        }
    }
    return rv;
}