449 lines
12 KiB
C
449 lines
12 KiB
C
/*
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing,
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* software distributed under the License is distributed on an
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* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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* KIND, either express or implied. See the License for the
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* specific language governing permissions and limitations
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* under the License.
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*/
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#include "error.h"
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#include "socket.h"
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#include <pthread.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <winsock2.h>
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/**
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* Data associated with an open socket which uses the Windows Socket API.
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*/
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typedef struct guac_socket_wsa_data {
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/**
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* The associated Windows socket handle.
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*/
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SOCKET sock;
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/**
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* The number of bytes currently in the main write buffer.
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*/
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int written;
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/**
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* The main write buffer. Bytes written go here before being flushed
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* to the open socket.
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*/
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char out_buf[GUAC_SOCKET_OUTPUT_BUFFER_SIZE];
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/**
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* Lock which is acquired when an instruction is being written, and
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* released when the instruction is finished being written.
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*/
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pthread_mutex_t socket_lock;
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/**
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* Lock which protects access to the internal buffer of this socket,
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* guaranteeing atomicity of writes and flushes.
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*/
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pthread_mutex_t buffer_lock;
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} guac_socket_wsa_data;
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/**
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* Writes the entire contents of the given buffer to the SOCKET handle
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* associated with the given socket, retrying as necessary until the whole
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* buffer is written, and aborting if an error occurs.
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*
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* @param socket
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* The guac_socket associated with the SOCKET handle to which the given
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* buffer should be written.
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*
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* @param buf
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* The buffer of data to write to the given guac_socket.
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*
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* @param count
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* The number of bytes within the given buffer.
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*
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* @return
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* The number of bytes written, which will be exactly the size of the given
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* buffer, or a negative value if an error occurs.
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*/
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ssize_t guac_socket_wsa_write(guac_socket* socket,
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const void* buf, size_t count) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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const char* buffer = buf;
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/* Write until completely written */
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while (count > 0) {
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int retval = send(data->sock, buffer, count, 0);
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/* Record errors in guac_error */
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if (retval < 0) {
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guac_error = GUAC_STATUS_SEE_ERRNO;
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guac_error_message = "Error writing data to socket";
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return retval;
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}
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/* Advance buffer as data retval */
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buffer += retval;
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count -= retval;
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}
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return 0;
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}
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/**
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* Attempts to read from the underlying SOCKET handle of the given guac_socket,
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* populating the given buffer.
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*
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* @param socket
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* The guac_socket being read from.
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*
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* @param buf
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* The arbitrary buffer which we must populate with data.
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*
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* @param count
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* The maximum number of bytes to read into the buffer.
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*
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* @return
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* The number of bytes read, or -1 if an error occurs.
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*/
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static ssize_t guac_socket_wsa_read_handler(guac_socket* socket,
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void* buf, size_t count) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Read from socket */
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int retval = recv(data->sock, buf, count, 0);
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/* Record errors in guac_error */
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if (retval < 0) {
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guac_error = GUAC_STATUS_SEE_ERRNO;
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guac_error_message = "Error reading data from socket";
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}
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return retval;
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}
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/**
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* Flushes the contents of the output buffer of the given socket immediately,
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* without first locking access to the output buffer. This function must ONLY
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* be called if the buffer lock has already been acquired.
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*
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* @param socket
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* The guac_socket to flush.
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*
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* @return
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* Zero if the flush operation was successful, non-zero otherwise.
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*/
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static ssize_t guac_socket_wsa_flush(guac_socket* socket) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Flush remaining bytes in buffer */
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if (data->written > 0) {
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/* Write ALL bytes in buffer immediately */
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if (guac_socket_wsa_write(socket, data->out_buf, data->written))
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return 1;
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data->written = 0;
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}
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return 0;
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}
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/**
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* Flushes the internal buffer of the given guac_socket, writing all data
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* to the underlying SOCKET handle.
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*
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* @param socket
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* The guac_socket to flush.
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*
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* @return
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* Zero if the flush operation was successful, non-zero otherwise.
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*/
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static ssize_t guac_socket_wsa_flush_handler(guac_socket* socket) {
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int retval;
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Acquire exclusive access to buffer */
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pthread_mutex_lock(&(data->buffer_lock));
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/* Flush contents of buffer */
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retval = guac_socket_wsa_flush(socket);
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/* Relinquish exclusive access to buffer */
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pthread_mutex_unlock(&(data->buffer_lock));
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return retval;
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}
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/**
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* Writes the contents of the buffer to the output buffer of the given socket,
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* flushing the output buffer as necessary, without first locking access to the
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* output buffer. This function must ONLY be called if the buffer lock has
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* already been acquired.
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*
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* @param socket
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* The guac_socket to write the given buffer to.
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*
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* @param buf
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* The buffer to write to the given socket.
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*
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* @param count
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* The number of bytes in the given buffer.
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*
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* @return
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* The number of bytes written, or a negative value if an error occurs
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* during write.
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*/
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static ssize_t guac_socket_wsa_write_buffered(guac_socket* socket,
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const void* buf, size_t count) {
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size_t original_count = count;
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const char* current = buf;
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Append to buffer, flush if necessary */
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while (count > 0) {
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int chunk_size;
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int remaining = sizeof(data->out_buf) - data->written;
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/* If no space left in buffer, flush and retry */
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if (remaining == 0) {
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/* Abort if error occurs during flush */
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if (guac_socket_wsa_flush(socket))
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return -1;
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/* Retry buffer append */
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continue;
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}
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/* Calculate size of chunk to be written to buffer */
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chunk_size = count;
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if (chunk_size > remaining)
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chunk_size = remaining;
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/* Update output buffer */
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memcpy(data->out_buf + data->written, current, chunk_size);
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data->written += chunk_size;
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/* Update provided buffer */
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current += chunk_size;
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count -= chunk_size;
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}
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/* All bytes have been written, possibly some to the internal buffer */
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return original_count;
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}
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/**
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* Appends the provided data to the internal buffer for future writing. The
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* actual write attempt will occur only upon flush, or when the internal buffer
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* is full.
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*
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* @param socket
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* The guac_socket being write to.
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*
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* @param buf
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* The arbitrary buffer containing the data to be written.
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*
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* @param count
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* The number of bytes contained within the buffer.
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*
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* @return
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* The number of bytes written, or -1 if an error occurs.
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*/
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static ssize_t guac_socket_wsa_write_handler(guac_socket* socket,
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const void* buf, size_t count) {
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int retval;
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Acquire exclusive access to buffer */
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pthread_mutex_lock(&(data->buffer_lock));
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/* Write provided data to buffer */
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retval = guac_socket_wsa_write_buffered(socket, buf, count);
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/* Relinquish exclusive access to buffer */
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pthread_mutex_unlock(&(data->buffer_lock));
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return retval;
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}
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/**
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* Waits for data on the underlying SOCKET handle of the given socket to
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* become available such that the next read operation will not block.
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*
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* @param socket
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* The guac_socket to wait for.
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*
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* @param usec_timeout
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* The maximum amount of time to wait for data, in microseconds, or -1 to
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* potentially wait forever.
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*
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* @return
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* A positive value on success, zero if the timeout elapsed and no data is
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* available, or a negative value if an error occurs.
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*/
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static int guac_socket_wsa_select_handler(guac_socket* socket,
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int usec_timeout) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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fd_set sockets;
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struct timeval timeout;
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int retval;
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/* Initialize fd_set with single underlying socket handle */
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FD_ZERO(&sockets);
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FD_SET(data->sock, &sockets);
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/* No timeout if usec_timeout is negative */
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if (usec_timeout < 0)
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retval = select(0, &sockets, NULL, NULL, NULL);
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/* Handle timeout if specified */
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else {
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timeout.tv_sec = usec_timeout / 1000000;
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timeout.tv_usec = usec_timeout % 1000000;
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retval = select(0, &sockets, NULL, NULL, &timeout);
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}
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/* Properly set guac_error */
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if (retval < 0) {
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guac_error = GUAC_STATUS_SEE_ERRNO;
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guac_error_message = "Error while waiting for data on socket";
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}
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if (retval == 0) {
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guac_error = GUAC_STATUS_TIMEOUT;
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guac_error_message = "Timeout while waiting for data on socket";
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}
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return retval;
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}
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/**
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* Frees all implementation-specific data associated with the given socket, but
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* not the socket object itself.
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*
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* @param socket
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* The guac_socket whose associated data should be freed.
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*
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* @return
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* Zero if the data was successfully freed, non-zero otherwise. This
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* implementation always succeeds, and will always return zero.
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*/
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static int guac_socket_wsa_free_handler(guac_socket* socket) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Destroy locks */
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pthread_mutex_destroy(&(data->socket_lock));
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pthread_mutex_destroy(&(data->buffer_lock));
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/* Close socket */
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closesocket(data->sock);
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free(data);
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return 0;
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}
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/**
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* Acquires exclusive access to the given socket.
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*
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* @param socket
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* The guac_socket to which exclusive access is required.
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*/
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static void guac_socket_wsa_lock_handler(guac_socket* socket) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Acquire exclusive access to socket */
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pthread_mutex_lock(&(data->socket_lock));
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}
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/**
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* Relinquishes exclusive access to the given socket.
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*
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* @param socket
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* The guac_socket to which exclusive access is no longer required.
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*/
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static void guac_socket_wsa_unlock_handler(guac_socket* socket) {
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guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
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/* Relinquish exclusive access to socket */
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pthread_mutex_unlock(&(data->socket_lock));
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}
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guac_socket* guac_socket_open_wsa(SOCKET sock) {
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pthread_mutexattr_t lock_attributes;
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/* Allocate socket and associated data */
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guac_socket* socket = guac_socket_alloc();
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guac_socket_wsa_data* data = malloc(sizeof(guac_socket_wsa_data));
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/* Store socket as socket data */
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data->sock = sock;
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data->written = 0;
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socket->data = data;
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pthread_mutexattr_init(&lock_attributes);
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pthread_mutexattr_setpshared(&lock_attributes, PTHREAD_PROCESS_SHARED);
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/* Init locks */
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pthread_mutex_init(&(data->socket_lock), &lock_attributes);
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pthread_mutex_init(&(data->buffer_lock), &lock_attributes);
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/* Set read/write handlers */
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socket->read_handler = guac_socket_wsa_read_handler;
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socket->write_handler = guac_socket_wsa_write_handler;
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socket->select_handler = guac_socket_wsa_select_handler;
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socket->lock_handler = guac_socket_wsa_lock_handler;
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socket->unlock_handler = guac_socket_wsa_unlock_handler;
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socket->flush_handler = guac_socket_wsa_flush_handler;
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socket->free_handler = guac_socket_wsa_free_handler;
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return socket;
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}
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