source: mainline/uspace/srv/hid/remcons/remcons.c@ e63e74a

/*
 * Copyright (c) 2023 Jiri Svoboda
 * Copyright (c) 2012 Vojtech Horky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup remcons
 * @{
 */
/** @file
 */

#include <async.h>
#include <errno.h>
#include <io/con_srv.h>
#include <stdio.h>
#include <stdlib.h>
#include <str_error.h>
#include <loc.h>
#include <io/keycode.h>
#include <align.h>
#include <fibril_synch.h>
#include <task.h>
#include <inet/addr.h>
#include <inet/endpoint.h>
#include <inet/tcp.h>
#include <io/console.h>
#include <inttypes.h>
#include <str.h>
#include "telnet.h"
#include "user.h"

#define APP_GETTERM  "/app/getterm"
#define APP_SHELL "/app/bdsh"

/** Telnet commands to force character mode
 * (redundant to be on the safe side).
 * See
 * http://stackoverflow.com/questions/273261/force-telnet-user-into-character-mode
 * for discussion.
 */
static const telnet_cmd_t telnet_force_character_mode_command[] = {
        TELNET_IAC, TELNET_WILL, TELNET_ECHO,
        TELNET_IAC, TELNET_WILL, TELNET_SUPPRESS_GO_AHEAD,
        TELNET_IAC, TELNET_WONT, TELNET_LINEMODE
};

static const size_t telnet_force_character_mode_command_count =
    sizeof(telnet_force_character_mode_command) / sizeof(telnet_cmd_t);

static errno_t remcons_open(con_srvs_t *, con_srv_t *);
static errno_t remcons_close(con_srv_t *);
static errno_t remcons_write(con_srv_t *, void *, size_t, size_t *);
static void remcons_sync(con_srv_t *);
static void remcons_clear(con_srv_t *);
static void remcons_set_pos(con_srv_t *, sysarg_t col, sysarg_t row);
static errno_t remcons_get_pos(con_srv_t *, sysarg_t *, sysarg_t *);
static errno_t remcons_get_size(con_srv_t *, sysarg_t *, sysarg_t *);
static errno_t remcons_get_color_cap(con_srv_t *, console_caps_t *);
static errno_t remcons_get_event(con_srv_t *, cons_event_t *);

static con_ops_t con_ops = {
        .open = remcons_open,
        .close = remcons_close,
        .read = NULL,
        .write = remcons_write,
        .sync = remcons_sync,
        .clear = remcons_clear,
        .set_pos = remcons_set_pos,
        .get_pos = remcons_get_pos,
        .get_size = remcons_get_size,
        .get_color_cap = remcons_get_color_cap,
        .set_style = NULL,
        .set_color = NULL,
        .set_rgb_color = NULL,
        .set_cursor_visibility = NULL,
        .get_event = remcons_get_event
};

static void remcons_new_conn(tcp_listener_t *lst, tcp_conn_t *conn);

static tcp_listen_cb_t listen_cb = {
        .new_conn = remcons_new_conn
};

static tcp_cb_t conn_cb = {
        .connected = NULL
};

static loc_srv_t *remcons_srv;

static telnet_user_t *srv_to_user(con_srv_t *srv)
{
        return srv->srvs->sarg;
}

static errno_t remcons_open(con_srvs_t *srvs, con_srv_t *srv)
{
        telnet_user_t *user = srv_to_user(srv);

        telnet_user_log(user, "New client connected (%p).", srv);

        /* Force character mode. */
        (void) tcp_conn_send(user->conn, (void *)telnet_force_character_mode_command,
            telnet_force_character_mode_command_count);

        return EOK;
}

static errno_t remcons_close(con_srv_t *srv)
{
        telnet_user_t *user = srv_to_user(srv);

        telnet_user_notify_client_disconnected(user);
        telnet_user_log(user, "Client disconnected (%p).", srv);

        return EOK;
}

static errno_t remcons_write(con_srv_t *srv, void *data, size_t size, size_t *nwritten)
{
        telnet_user_t *user = srv_to_user(srv);
        errno_t rc;

        rc = telnet_user_send_data(user, data, size);
        if (rc != EOK)
                return rc;

        *nwritten = size;
        return EOK;
}

static void remcons_sync(con_srv_t *srv)
{
        (void) srv;
}

static void remcons_clear(con_srv_t *srv)
{
        (void) srv;
}

static void remcons_set_pos(con_srv_t *srv, sysarg_t col, sysarg_t row)
{
        telnet_user_t *user = srv_to_user(srv);

        telnet_user_update_cursor_x(user, col);
}

static errno_t remcons_get_pos(con_srv_t *srv, sysarg_t *col, sysarg_t *row)
{
        telnet_user_t *user = srv_to_user(srv);

        *col = user->cursor_x;
        *row = 0;

        return EOK;
}

static errno_t remcons_get_size(con_srv_t *srv, sysarg_t *cols, sysarg_t *rows)
{
        (void) srv;

        *cols = 100;
        *rows = 1;

        return EOK;
}

static errno_t remcons_get_color_cap(con_srv_t *srv, console_caps_t *ccaps)
{
        (void) srv;
        *ccaps = CONSOLE_CAP_NONE;

        return EOK;
}

static errno_t remcons_get_event(con_srv_t *srv, cons_event_t *event)
{
        telnet_user_t *user = srv_to_user(srv);
        kbd_event_t kevent;
        errno_t rc;

        rc = telnet_user_get_next_keyboard_event(user, &kevent);
        if (rc != EOK) {
                /* XXX What? */
                memset(event, 0, sizeof(*event));
                return EOK;
        }

        event->type = CEV_KEY;
        event->ev.key = kevent;

        return EOK;
}

/** Callback when client connects to a telnet terminal. */
static void client_connection(ipc_call_t *icall, void *arg)
{
        /* Find the user. */
        telnet_user_t *user = telnet_user_get_for_client_connection(ipc_get_arg2(icall));
        if (user == NULL) {
                async_answer_0(icall, ENOENT);
                return;
        }

        /* Handle messages. */
        con_conn(icall, &user->srvs);
}

/** Fibril for spawning the task running after user connects.
 *
 * @param arg Corresponding @c telnet_user_t structure.
 */
static errno_t spawn_task_fibril(void *arg)
{
        telnet_user_t *user = arg;

        task_id_t task;
        task_wait_t wait;
        errno_t rc = task_spawnl(&task, &wait, APP_GETTERM, APP_GETTERM, user->service_name,
            "/loc", "--msg", "--", APP_SHELL, NULL);
        if (rc != EOK) {
                telnet_user_error(user, "Spawning `%s %s /loc --msg -- %s' "
                    "failed: %s.", APP_GETTERM, user->service_name, APP_SHELL,
                    str_error(rc));
                fibril_mutex_lock(&user->guard);
                user->task_finished = true;
                user->srvs.aborted = true;
                fibril_condvar_signal(&user->refcount_cv);
                fibril_mutex_unlock(&user->guard);
                return EOK;
        }

        fibril_mutex_lock(&user->guard);
        user->task_id = task;
        fibril_mutex_unlock(&user->guard);

        task_exit_t task_exit;
        int task_retval;
        task_wait(&wait, &task_exit, &task_retval);
        telnet_user_log(user, "%s terminated %s, exit code %d.", APP_GETTERM,
            task_exit == TASK_EXIT_NORMAL ? "normally" : "unexpectedly",
            task_retval);

        /* Announce destruction. */
        fibril_mutex_lock(&user->guard);
        user->task_finished = true;
        user->srvs.aborted = true;
        fibril_condvar_signal(&user->refcount_cv);
        fibril_mutex_unlock(&user->guard);

        return EOK;
}

/** Tell whether given user can be destroyed (has no active clients).
 *
 * @param user The telnet user in question.
 */
static bool user_can_be_destroyed_no_lock(telnet_user_t *user)
{
        return user->task_finished && user->socket_closed &&
            (user->locsrv_connection_count == 0);
}

/** Handle network connection.
 *
 * @param lst  Listener
 * @param conn Connection
 */
static void remcons_new_conn(tcp_listener_t *lst, tcp_conn_t *conn)
{
        telnet_user_t *user = telnet_user_create(conn);
        assert(user);

        con_srvs_init(&user->srvs);
        user->srvs.ops = &con_ops;
        user->srvs.sarg = user;
        user->srvs.abort_timeout = 1000;

        telnet_user_add(user);

        errno_t rc = loc_service_register(remcons_srv, user->service_name,
            &user->service_id);
        if (rc != EOK) {
                telnet_user_error(user, "Unable to register %s with loc: %s.",
                    user->service_name, str_error(rc));
                return;
        }

        telnet_user_log(user, "Service %s registerd with id %" PRIun ".",
            user->service_name, user->service_id);

        fid_t spawn_fibril = fibril_create(spawn_task_fibril, user);
        assert(spawn_fibril);
        fibril_add_ready(spawn_fibril);

        /* Wait for all clients to exit. */
        fibril_mutex_lock(&user->guard);
        while (!user_can_be_destroyed_no_lock(user)) {
                if (user->task_finished) {
                        user->conn = NULL;
                        user->socket_closed = true;
                        user->srvs.aborted = true;
                        continue;
                } else if (user->socket_closed) {
                        if (user->task_id != 0) {
                                task_kill(user->task_id);
                        }
                }
                fibril_condvar_wait_timeout(&user->refcount_cv, &user->guard, 1000);
        }
        fibril_mutex_unlock(&user->guard);

        rc = loc_service_unregister(remcons_srv, user->service_id);
        if (rc != EOK) {
                telnet_user_error(user,
                    "Unable to unregister %s from loc: %s (ignored).",
                    user->service_name, str_error(rc));
        }

        telnet_user_log(user, "Destroying...");
        telnet_user_destroy(user);
}

int main(int argc, char *argv[])
{
        errno_t rc;
        tcp_listener_t *lst;
        tcp_t *tcp;
        inet_ep_t ep;

        async_set_fallback_port_handler(client_connection, NULL);
        rc = loc_server_register(NAME, &remcons_srv);
        if (rc != EOK) {
                fprintf(stderr, "%s: Unable to register server\n", NAME);
                return rc;
        }

        rc = tcp_create(&tcp);
        if (rc != EOK) {
                fprintf(stderr, "%s: Error initializing TCP.\n", NAME);
                return rc;
        }

        inet_ep_init(&ep);
        ep.port = 2223;

        rc = tcp_listener_create(tcp, &ep, &listen_cb, NULL, &conn_cb, NULL,
            &lst);
        if (rc != EOK) {
                fprintf(stderr, "%s: Error creating listener.\n", NAME);
                return rc;
        }

        printf("%s: HelenOS Remote console service\n", NAME);
        task_retval(0);
        async_manager();

        /* Not reached */
        return 0;
}

/** @}
 */