src/protocols/vnc/clipboard.c

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

#include "client.h"
#include "clipboard.h"
#include "common/clipboard.h"
#include "common/iconv.h"
#include "user.h"
#include "vnc.h"

#include <guacamole/client.h>
#include <guacamole/mem.h>
#include <guacamole/stream.h>
#include <guacamole/user.h>
#include <rfb/rfbclient.h>
#include <rfb/rfbconfig.h>
#include <rfb/rfbproto.h>

int guac_vnc_set_clipboard_encoding(guac_client* client,
        const char* name) {

    guac_vnc_client* vnc_client = (guac_vnc_client*) client->data;

    /* Use ISO8859-1 if explicitly selected or NULL */
    if (name == NULL || strcmp(name, "ISO8859-1") == 0) {
        vnc_client->clipboard_reader = GUAC_READ_ISO8859_1;
        vnc_client->clipboard_writer = GUAC_WRITE_ISO8859_1;
        return 0;
    }

    /* UTF-8 */
    if (strcmp(name, "UTF-8") == 0) {
        vnc_client->clipboard_reader = GUAC_READ_UTF8;
        vnc_client->clipboard_writer = GUAC_WRITE_UTF8;
        return 1;
    }

    /* UTF-16 */
    if (strcmp(name, "UTF-16") == 0) {
        vnc_client->clipboard_reader = GUAC_READ_UTF16;
        vnc_client->clipboard_writer = GUAC_WRITE_UTF16;
        return 1;
    }

    /* CP1252 */
    if (strcmp(name, "CP1252") == 0) {
        vnc_client->clipboard_reader = GUAC_READ_CP1252;
        vnc_client->clipboard_writer = GUAC_WRITE_CP1252;
        return 1;
    }

    /* MacRoman */
    if (strcmp(name, "MacRoman") == 0) {
        vnc_client->clipboard_reader = GUAC_READ_MACROMAN;
        vnc_client->clipboard_writer = GUAC_WRITE_MACROMAN;
        return 1;
    }

    /* If encoding unrecognized, warn and default to ISO8859-1 */
    guac_client_log(client, GUAC_LOG_WARNING,
            "Encoding '%s' is invalid. Defaulting to ISO8859-1.", name);

    vnc_client->clipboard_reader = GUAC_READ_ISO8859_1;
    vnc_client->clipboard_writer = GUAC_WRITE_ISO8859_1;
    return 0;

}

int guac_vnc_clipboard_handler(guac_user* user, guac_stream* stream,
        char* mimetype) {

    /* Clear clipboard and prepare for new data */
    guac_vnc_client* vnc_client = (guac_vnc_client*) user->client->data;
    guac_common_clipboard_reset(vnc_client->clipboard, mimetype);

    /* Set handlers for clipboard stream */
    stream->blob_handler = guac_vnc_clipboard_blob_handler;
    stream->end_handler = guac_vnc_clipboard_end_handler;

    return 0;
}

int guac_vnc_clipboard_blob_handler(guac_user* user, guac_stream* stream,
        void* data, int length) {

    /* Append new data */
    guac_vnc_client* vnc_client = (guac_vnc_client*) user->client->data;
    guac_common_clipboard_append(vnc_client->clipboard, (char*) data, length);

    return 0;
}

int guac_vnc_clipboard_end_handler(guac_user* user, guac_stream* stream) {

    guac_vnc_client* vnc_client = (guac_vnc_client*) user->client->data;
    guac_client* client = user->client;
    rfbClient* rfb_client = vnc_client->rfb_client;

    /* Send via VNC only if finished connecting */
    if (rfb_client == NULL)
        return 0;

#ifdef LIBVNC_CLIENT_HAS_EXTENDED_CLIPBOARD
    /*
     * Guacamole stores clipboard text as UTF-8. The clipboard-encoding
     * setting only applies to the classic VNC clipboard path, where text
     * must be converted from UTF-8 to the configured wire encoding.
     *
     * If clipboard-encoding is UTF-8, try the Extended Clipboard  path first
     * since it can send UTF-8 directly. Otherwise, or if that fails, fall
     * back to classic clipboard conversion.
     *
     * Text coming back from the VNC server follows the same idea in reverse:
     * classic clipboard text is decoded using clipboard-encoding, while
     * Extended Clipboard text is already UTF-8.
     */

    const char* clipboard_encoding = vnc_client->settings->clipboard_encoding;
    int use_utf8_clipboard = clipboard_encoding != NULL &&
        strcmp(clipboard_encoding, "UTF-8") == 0;

    if (use_utf8_clipboard) {
        if (SendClientCutTextUTF8(rfb_client, vnc_client->clipboard->buffer,
                    vnc_client->clipboard->length))
            return 0;
    }
#endif

    /* Fall back to classic clipboard with encoding conversion */
    char* output_data = guac_mem_alloc(GUAC_COMMON_CLIPBOARD_MAX_LENGTH);
    if (output_data == NULL) {
        guac_client_log(client, GUAC_LOG_WARNING,
                "Clipboard conversion failed: unable to allocate output "
                "buffer.");
        return 1;
    }

    const char* input = vnc_client->clipboard->buffer;
    char* output = output_data;
    guac_iconv_write* writer = vnc_client->clipboard_writer;

    /* Convert clipboard contents */
    guac_iconv(GUAC_READ_UTF8, &input, vnc_client->clipboard->length,
            writer, &output, GUAC_COMMON_CLIPBOARD_MAX_LENGTH);

    SendClientCutText(rfb_client, output_data, output - output_data);

    guac_mem_free(output_data);
    return 0;
}

void guac_vnc_cut_text(rfbClient* client, const char* text, int textlen) {

    guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
    guac_vnc_client* vnc_client = (guac_vnc_client*) gc->data;

    /* Ignore received text if outbound clipboard transfer is disabled */
    if (vnc_client->settings->disable_copy)
        return;

    char* received_data = guac_mem_alloc(GUAC_COMMON_CLIPBOARD_MAX_LENGTH);
    if (received_data == NULL) {
        guac_client_log(gc, GUAC_LOG_WARNING,
                "Clipboard conversion failed: unable to allocate receive "
                "buffer.");
        return;
    }

    const char* input = text;
    char* output = received_data;
    guac_iconv_read* reader = vnc_client->clipboard_reader;

    /* Convert clipboard contents */
    guac_iconv(reader, &input, textlen,
            GUAC_WRITE_UTF8, &output, GUAC_COMMON_CLIPBOARD_MAX_LENGTH);

    /* Send converted data */
    guac_common_clipboard_reset(vnc_client->clipboard, "text/plain");
    guac_common_clipboard_append(vnc_client->clipboard, received_data, output - received_data);
    guac_common_clipboard_send(vnc_client->clipboard, gc);

    guac_mem_free(received_data);

}

#ifdef LIBVNC_CLIENT_HAS_EXTENDED_CLIPBOARD
void guac_vnc_cut_text_utf8(rfbClient* client, const char* text, int textlen) {

    guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
    guac_vnc_client* vnc_client = (guac_vnc_client*) gc->data;

    /* Ignore received text if outbound clipboard transfer is disabled */
    if (vnc_client->settings->disable_copy)
        return;

    char* received_data = guac_mem_alloc(GUAC_COMMON_CLIPBOARD_MAX_LENGTH);
    if (received_data == NULL) {
        guac_client_log(gc, GUAC_LOG_WARNING,
                "Clipboard conversion failed: unable to allocate UTF-8 "
                "receive buffer.");
        return;
    }

    const char* input = text;
    char* output = received_data;

    /* Extended clipboard always delivers UTF-8; iconv() here enforces
     * GUAC_COMMON_CLIPBOARD_MAX_LENGTH and replaces invalid lead bytes
     * with the Unicode replacement character (U+FFFD, ?) */
    guac_iconv(GUAC_READ_UTF8, &input, textlen,
            GUAC_WRITE_UTF8, &output, GUAC_COMMON_CLIPBOARD_MAX_LENGTH);

    /* Send converted data */
    guac_common_clipboard_reset(vnc_client->clipboard, "text/plain");
    guac_common_clipboard_append(vnc_client->clipboard, received_data, output - received_data);
    guac_common_clipboard_send(vnc_client->clipboard, gc);

    guac_mem_free(received_data);

}
#endif