source: mainline/uspace/srv/hid/remcons/user.c@ c23a1fe

/*
 * Copyright (c) 2024 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 <stdio.h>
#include <stdlib.h>
#include <adt/prodcons.h>
#include <errno.h>
#include <macros.h>
#include <mem.h>
#include <str_error.h>
#include <loc.h>
#include <io/keycode.h>
#include <align.h>
#include <as.h>
#include <fibril_synch.h>
#include <task.h>
#include <inet/tcp.h>
#include <io/console.h>
#include <inttypes.h>
#include <assert.h>
#include "remcons.h"
#include "user.h"
#include "telnet.h"

static FIBRIL_MUTEX_INITIALIZE(users_guard);
static LIST_INITIALIZE(users);

/** Create new telnet user.
 *
 * @param conn Incoming connection.
 * @return New telnet user or NULL when out of memory.
 */
telnet_user_t *telnet_user_create(tcp_conn_t *conn)
{
        static int telnet_user_id_counter = 0;

        telnet_user_t *user = malloc(sizeof(telnet_user_t));
        if (user == NULL) {
                return NULL;
        }

        user->id = ++telnet_user_id_counter;

        int rc = asprintf(&user->service_name, "%s/telnet%u.%d", NAMESPACE,
            (unsigned)task_get_id(), user->id);
        if (rc < 0) {
                free(user);
                return NULL;
        }

        user->conn = conn;
        user->service_id = (service_id_t) -1;
        prodcons_initialize(&user->in_events);
        link_initialize(&user->link);
        user->socket_buffer_len = 0;
        user->socket_buffer_pos = 0;
        user->send_buf_used = 0;

        fibril_condvar_initialize(&user->refcount_cv);
        fibril_mutex_initialize(&user->guard);
        user->task_finished = false;
        user->socket_closed = false;
        user->locsrv_connection_count = 0;

        user->cursor_x = 0;
        user->cursor_y = 0;

        return user;
}

void telnet_user_add(telnet_user_t *user)
{
        fibril_mutex_lock(&users_guard);
        list_append(&user->link, &users);
        fibril_mutex_unlock(&users_guard);
}

/** Destroy telnet user structure.
 *
 * @param user User to be destroyed.
 */
void telnet_user_destroy(telnet_user_t *user)
{
        assert(user);

        fibril_mutex_lock(&users_guard);
        list_remove(&user->link);
        fibril_mutex_unlock(&users_guard);

        free(user);
}

/** Find user by service id and increments reference counter.
 *
 * @param id Location service id of the telnet user's terminal.
 */
telnet_user_t *telnet_user_get_for_client_connection(service_id_t id)
{
        telnet_user_t *user = NULL;

        fibril_mutex_lock(&users_guard);
        list_foreach(users, link, telnet_user_t, tmp) {
                if (tmp->service_id == id) {
                        user = tmp;
                        break;
                }
        }
        if (user == NULL) {
                fibril_mutex_unlock(&users_guard);
                return NULL;
        }

        telnet_user_t *tmp = user;
        fibril_mutex_lock(&tmp->guard);
        user->locsrv_connection_count++;

        /*
         * Refuse to return user whose task already finished or when
         * the socket is already closed().
         */
        if (user->task_finished || user->socket_closed) {
                user = NULL;
                user->locsrv_connection_count--;
        }

        fibril_mutex_unlock(&tmp->guard);

        fibril_mutex_unlock(&users_guard);

        return user;
}

/** Notify that client disconnected from the remote terminal.
 *
 * @param user To which user the client was connected.
 */
void telnet_user_notify_client_disconnected(telnet_user_t *user)
{
        fibril_mutex_lock(&user->guard);
        assert(user->locsrv_connection_count > 0);
        user->locsrv_connection_count--;
        fibril_condvar_signal(&user->refcount_cv);
        fibril_mutex_unlock(&user->guard);
}

/** Tell whether the launched task already exited and socket is already closed.
 *
 * @param user Telnet user in question.
 */
bool telnet_user_is_zombie(telnet_user_t *user)
{
        fibril_mutex_lock(&user->guard);
        bool zombie = user->socket_closed || user->task_finished;
        fibril_mutex_unlock(&user->guard);

        return zombie;
}

static errno_t telnet_user_fill_recv_buf(telnet_user_t *user)
{
        errno_t rc;
        size_t recv_length;

        rc = tcp_conn_recv_wait(user->conn, user->socket_buffer,
            BUFFER_SIZE, &recv_length);
        if (rc != EOK)
                return rc;

        if (recv_length == 0) {
                user->socket_closed = true;
                user->srvs.aborted = true;
                return ENOENT;
        }

        user->socket_buffer_len = recv_length;
        user->socket_buffer_pos = 0;

        return EOK;
}

/** Receive next byte from a socket (use buffering.
 * We need to return the value via extra argument because the read byte
 * might be negative.
 */
static errno_t telnet_user_recv_next_byte_no_lock(telnet_user_t *user, char *byte)
{
        errno_t rc;

        /* No more buffered data? */
        if (user->socket_buffer_len <= user->socket_buffer_pos) {
                rc = telnet_user_fill_recv_buf(user);
                if (rc != EOK)
                        return rc;
        }

        *byte = user->socket_buffer[user->socket_buffer_pos++];
        return EOK;
}

errno_t telnet_user_recv(telnet_user_t *user, void *data, size_t size,
    size_t *nread)
{
        errno_t rc;
        size_t nb;

        /* No more buffered data? */
        if (user->socket_buffer_len <= user->socket_buffer_pos) {
                rc = telnet_user_fill_recv_buf(user);
                if (rc != EOK)
                        return rc;
        }

        nb = user->socket_buffer_len - user->socket_buffer_pos;
        memcpy(data, user->socket_buffer + user->socket_buffer_pos, nb);
        user->socket_buffer_pos += nb;
        *nread = nb;
        return EOK;
}

/** Creates new keyboard event from given char.
 *
 * @param type Event type (press / release).
 * @param c Pressed character.
 */
static kbd_event_t *new_kbd_event(kbd_event_type_t type, char32_t c)
{
        kbd_event_t *event = malloc(sizeof(kbd_event_t));
        assert(event);

        link_initialize(&event->link);
        event->type = type;
        event->c = c;
        event->mods = 0;

        switch (c) {
        case '\n':
                event->key = KC_ENTER;
                break;
        case '\t':
                event->key = KC_TAB;
                break;
        case '\b':
        case 127: /* This is what Linux telnet sends. */
                event->key = KC_BACKSPACE;
                event->c = '\b';
                break;
        default:
                event->key = KC_A;
                break;
        }

        return event;
}

/** Process telnet command (currently only print to screen).
 *
 * @param user Telnet user structure.
 * @param option_code Command option code.
 * @param cmd Telnet command.
 */
static void process_telnet_command(telnet_user_t *user,
    telnet_cmd_t option_code, telnet_cmd_t cmd)
{
        if (option_code != 0) {
                telnet_user_log(user, "Ignoring telnet command %u %u %u.",
                    TELNET_IAC, option_code, cmd);
        } else {
                telnet_user_log(user, "Ignoring telnet command %u %u.",
                    TELNET_IAC, cmd);
        }
}

/** Get next keyboard event.
 *
 * @param user Telnet user.
 * @param event Where to store the keyboard event.
 * @return Error code.
 */
errno_t telnet_user_get_next_keyboard_event(telnet_user_t *user, kbd_event_t *event)
{
        fibril_mutex_lock(&user->guard);
        if (list_empty(&user->in_events.list)) {
                char next_byte = 0;
                bool inside_telnet_command = false;

                telnet_cmd_t telnet_option_code = 0;

                /* Skip zeros, bail-out on error. */
                while (next_byte == 0) {
                        fibril_mutex_unlock(&user->guard);

                        errno_t rc = telnet_user_recv_next_byte_no_lock(user, &next_byte);
                        if (rc != EOK)
                                return rc;

                        uint8_t byte = (uint8_t) next_byte;
                        fibril_mutex_lock(&user->guard);

                        /* Skip telnet commands. */
                        if (inside_telnet_command) {
                                inside_telnet_command = false;
                                next_byte = 0;
                                if (TELNET_IS_OPTION_CODE(byte)) {
                                        telnet_option_code = byte;
                                        inside_telnet_command = true;
                                } else {
                                        process_telnet_command(user,
                                            telnet_option_code, byte);
                                }
                        }
                        if (byte == TELNET_IAC) {
                                inside_telnet_command = true;
                                next_byte = 0;
                        }
                }

                /* CR-LF conversions. */
                if (next_byte == 13) {
                        next_byte = 10;
                }

                kbd_event_t *down = new_kbd_event(KEY_PRESS, next_byte);
                kbd_event_t *up = new_kbd_event(KEY_RELEASE, next_byte);
                assert(down);
                assert(up);
                prodcons_produce(&user->in_events, &down->link);
                prodcons_produce(&user->in_events, &up->link);
        }

        link_t *link = prodcons_consume(&user->in_events);
        kbd_event_t *tmp = list_get_instance(link, kbd_event_t, link);

        fibril_mutex_unlock(&user->guard);

        *event = *tmp;

        free(tmp);

        return EOK;
}

static errno_t telnet_user_send_raw(telnet_user_t *user,
    const void *data, size_t size)
{
        size_t remain;
        size_t now;
        errno_t rc;

        remain = sizeof(user->send_buf) - user->send_buf_used;
        while (size > 0) {
                if (remain == 0) {
                        rc = tcp_conn_send(user->conn, user->send_buf,
                            sizeof(user->send_buf));
                        if (rc != EOK)
                                return rc;

                        user->send_buf_used = 0;
                        remain = sizeof(user->send_buf);
                }

                now = min(remain, size);
                memcpy(user->send_buf + user->send_buf_used, data, now);
                user->send_buf_used += now;
                remain -= now;
                data += now;
                size -= now;
        }

        return EOK;
}

/** Send data (convert them first) to the socket, no locking.
 *
 * @param user Telnet user.
 * @param data Data buffer (not zero terminated).
 * @param size Size of @p data buffer in bytes.
 */
static errno_t telnet_user_send_data_no_lock(telnet_user_t *user,
    const char *data, size_t size)
{
        uint8_t *converted = malloc(3 * size + 1);
        assert(converted);
        int converted_size = 0;

        /* Convert new-lines. */
        for (size_t i = 0; i < size; i++) {
                if (data[i] == 10) {
                        converted[converted_size++] = 13;
                        converted[converted_size++] = 10;
                        user->cursor_x = 0;
                        if (user->cursor_y < (int)user->rows - 1)
                                ++user->cursor_y;
                } else {
                        converted[converted_size++] = data[i];
                        if (data[i] == '\b') {
                                user->cursor_x--;
                        } else {
                                user->cursor_x++;
                        }
                }
        }

        errno_t rc = telnet_user_send_raw(user, converted, converted_size);
        free(converted);

        return rc;
}

/** Send data (convert them first) to the socket.
 *
 * @param user Telnet user.
 * @param data Data buffer (not zero terminated).
 * @param size Size of @p data buffer in bytes.
 */
errno_t telnet_user_send_data(telnet_user_t *user, const char *data,
    size_t size)
{
        fibril_mutex_lock(&user->guard);

        errno_t rc = telnet_user_send_data_no_lock(user, data, size);

        fibril_mutex_unlock(&user->guard);

        return rc;
}

errno_t telnet_user_flush(telnet_user_t *user)
{
        errno_t rc;

        fibril_mutex_lock(&user->guard);
        rc = tcp_conn_send(user->conn, user->send_buf, user->send_buf_used);

        if (rc != EOK) {
                fibril_mutex_unlock(&user->guard);
                return rc;
        }

        user->send_buf_used = 0;
        fibril_mutex_unlock(&user->guard);
        return EOK;
}

/** Update cursor X position.
 *
 * This call may result in sending control commands over socket.
 *
 * @param user Telnet user.
 * @param new_x New cursor location.
 */
void telnet_user_update_cursor_x(telnet_user_t *user, int new_x)
{
        fibril_mutex_lock(&user->guard);
        if (user->cursor_x - 1 == new_x) {
                char data = '\b';
                /* Ignore errors. */
                telnet_user_send_data_no_lock(user, &data, 1);
        }
        user->cursor_x = new_x;
        fibril_mutex_unlock(&user->guard);

}

/**
 * @}
 */