| /* |
| * 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 "config.h" |
| |
| #include "guacamole/protocol.h" |
| #include "guacamole/socket.h" |
| #include "guacamole/unicode.h" |
| |
| #include <stddef.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| /** |
| * The maximum number of bytes to buffer before sending a "nest" instruction. |
| * As some of the 8 KB space available for each instruction will be taken up by |
| * the "nest" opcode and other parameters, and 1 KB will be more than enough |
| * space for that extra data, this space is reduced to an even 7 KB. |
| */ |
| #define GUAC_SOCKET_NEST_BUFFER_SIZE 7168 |
| |
| /** |
| * Internal data associated with an open socket which writes via a series of |
| * "nest" instructions to some underlying, parent socket. |
| */ |
| typedef struct guac_socket_nest_data { |
| |
| /** |
| * The underlying socket which should be used to write "nest" instructions. |
| */ |
| guac_socket* parent; |
| |
| /** |
| * The arbitrary index of the nested socket, assigned at time of |
| * allocation. |
| */ |
| int index; |
| |
| /** |
| * The number of bytes currently in the main write buffer. |
| */ |
| int written; |
| |
| /** |
| * The main write buffer. Bytes written go here before being flushed |
| * as nest instructions. Space is included for the null terminator |
| * required by guac_protocol_send_nest(). |
| */ |
| char buffer[GUAC_SOCKET_NEST_BUFFER_SIZE]; |
| |
| /** |
| * Lock which is acquired when an instruction is being written, and |
| * released when the instruction is finished being written. |
| */ |
| pthread_mutex_t socket_lock; |
| |
| /** |
| * Lock which protects access to the internal buffer of this socket, |
| * guaranteeing atomicity of writes and flushes. |
| */ |
| pthread_mutex_t buffer_lock; |
| |
| } guac_socket_nest_data; |
| |
| /** |
| * Flushes the contents of the output buffer of the given socket immediately, |
| * without first locking access to the output buffer. This function must ONLY |
| * be called if the buffer lock has already been acquired. |
| * |
| * @param socket |
| * The guac_socket to flush. |
| * |
| * @return |
| * Zero if the flush operation was successful, non-zero otherwise. |
| */ |
| static ssize_t guac_socket_nest_flush(guac_socket* socket) { |
| |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| |
| /* Flush remaining bytes in buffer */ |
| if (data->written > 0) { |
| |
| /* Determine length of buffer containing complete UTF-8 characters |
| * (buffer may end with a partial, multi-byte character) */ |
| int length = 0; |
| while (length < data->written) |
| length += guac_utf8_charsize(*(data->buffer + length)); |
| |
| /* Add null terminator, preserving overwritten character for later |
| * restoration (guac_protocol_send_nest() requires null-terminated |
| * strings) */ |
| char overwritten = data->buffer[length]; |
| data->buffer[length] = '\0'; |
| |
| /* Write ALL bytes in buffer as nest instruction */ |
| int retval = guac_protocol_send_nest(data->parent, data->index, data->buffer); |
| |
| /* Restore original value overwritten by null terminator */ |
| data->buffer[length] = overwritten; |
| |
| if (retval) |
| return 1; |
| |
| /* Shift any remaining data to beginning of buffer */ |
| memcpy(data->buffer, data->buffer + length, data->written - length); |
| data->written -= length; |
| |
| } |
| |
| return 0; |
| |
| } |
| |
| /** |
| * Flushes the internal buffer of the given guac_socket, writing all data |
| * to the underlying socket using "nest" instructions. |
| * |
| * @param socket |
| * The guac_socket to flush. |
| * |
| * @return |
| * Zero if the flush operation was successful, non-zero otherwise. |
| */ |
| static ssize_t guac_socket_nest_flush_handler(guac_socket* socket) { |
| |
| int retval; |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| |
| /* Acquire exclusive access to buffer */ |
| pthread_mutex_lock(&(data->buffer_lock)); |
| |
| /* Flush contents of buffer */ |
| retval = guac_socket_nest_flush(socket); |
| |
| /* Relinquish exclusive access to buffer */ |
| pthread_mutex_unlock(&(data->buffer_lock)); |
| |
| return retval; |
| |
| } |
| |
| /** |
| * Writes the contents of the buffer to the output buffer of the given socket, |
| * flushing the output buffer as necessary, without first locking access to the |
| * output buffer. This function must ONLY be called if the buffer lock has |
| * already been acquired. |
| * |
| * @param socket |
| * The guac_socket to write the given buffer to. |
| * |
| * @param buf |
| * The buffer to write to the given socket. |
| * |
| * @param count |
| * The number of bytes in the given buffer. |
| * |
| * @return |
| * The number of bytes written, or a negative value if an error occurs |
| * during write. |
| */ |
| static ssize_t guac_socket_nest_write_buffered(guac_socket* socket, |
| const void* buf, size_t count) { |
| |
| size_t original_count = count; |
| const char* current = buf; |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| |
| /* Append to buffer, flush if necessary */ |
| while (count > 0) { |
| |
| int chunk_size; |
| |
| /* Calculate space remaining, including one extra byte for the null |
| * terminator added upon flush */ |
| int remaining = sizeof(data->buffer) - data->written - 1; |
| |
| /* If no space left in buffer, flush and retry */ |
| if (remaining == 0) { |
| |
| /* Abort if error occurs during flush */ |
| if (guac_socket_nest_flush(socket)) |
| return -1; |
| |
| /* Retry buffer append */ |
| continue; |
| |
| } |
| |
| /* Calculate size of chunk to be written to buffer */ |
| chunk_size = count; |
| if (chunk_size > remaining) |
| chunk_size = remaining; |
| |
| /* Update output buffer */ |
| memcpy(data->buffer + data->written, current, chunk_size); |
| data->written += chunk_size; |
| |
| /* Update provided buffer */ |
| current += chunk_size; |
| count -= chunk_size; |
| |
| } |
| |
| /* All bytes have been written, possibly some to the internal buffer */ |
| return original_count; |
| |
| } |
| |
| /** |
| * Appends the provided data to the internal buffer for future writing. The |
| * actual write attempt will occur only upon flush, or when the internal buffer |
| * is full. |
| * |
| * @param socket |
| * The guac_socket being write to. |
| * |
| * @param buf |
| * The arbitrary buffer containing the data to be written. |
| * |
| * @param count |
| * The number of bytes contained within the buffer. |
| * |
| * @return |
| * The number of bytes written, or -1 if an error occurs. |
| */ |
| static ssize_t guac_socket_nest_write_handler(guac_socket* socket, |
| const void* buf, size_t count) { |
| |
| int retval; |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| |
| /* Acquire exclusive access to buffer */ |
| pthread_mutex_lock(&(data->buffer_lock)); |
| |
| /* Write provided data to buffer */ |
| retval = guac_socket_nest_write_buffered(socket, buf, count); |
| |
| /* Relinquish exclusive access to buffer */ |
| pthread_mutex_unlock(&(data->buffer_lock)); |
| |
| return retval; |
| |
| } |
| |
| /** |
| * Frees all implementation-specific data associated with the given socket, but |
| * not the socket object itself. |
| * |
| * @param socket |
| * The guac_socket whose associated data should be freed. |
| * |
| * @return |
| * Zero if the data was successfully freed, non-zero otherwise. This |
| * implementation always succeeds, and will always return zero. |
| */ |
| static int guac_socket_nest_free_handler(guac_socket* socket) { |
| |
| /* Free associated data */ |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| free(data); |
| |
| return 0; |
| |
| } |
| |
| /** |
| * Acquires exclusive access to the given socket. |
| * |
| * @param socket |
| * The guac_socket to which exclusive access is required. |
| */ |
| static void guac_socket_nest_lock_handler(guac_socket* socket) { |
| |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| |
| /* Acquire exclusive access to socket */ |
| pthread_mutex_lock(&(data->socket_lock)); |
| |
| } |
| |
| /** |
| * Relinquishes exclusive access to the given socket. |
| * |
| * @param socket |
| * The guac_socket to which exclusive access is no longer required. |
| */ |
| static void guac_socket_nest_unlock_handler(guac_socket* socket) { |
| |
| guac_socket_nest_data* data = (guac_socket_nest_data*) socket->data; |
| |
| /* Relinquish exclusive access to socket */ |
| pthread_mutex_unlock(&(data->socket_lock)); |
| |
| } |
| |
| guac_socket* guac_socket_nest(guac_socket* parent, int index) { |
| |
| /* Allocate socket and associated data */ |
| guac_socket* socket = guac_socket_alloc(); |
| guac_socket_nest_data* data = malloc(sizeof(guac_socket_nest_data)); |
| |
| /* Store nested socket details as socket data */ |
| data->parent = parent; |
| data->index = index; |
| socket->data = data; |
| |
| /* Set relevant handlers */ |
| socket->write_handler = guac_socket_nest_write_handler; |
| socket->lock_handler = guac_socket_nest_lock_handler; |
| socket->unlock_handler = guac_socket_nest_unlock_handler; |
| socket->flush_handler = guac_socket_nest_flush_handler; |
| socket->free_handler = guac_socket_nest_free_handler; |
| |
| return socket; |
| |
| } |
| |