guacamole-spice-protocol/src/libguac/socket-wsa.c

449 lines
12 KiB
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 "error.h"
#include "socket.h"
#include <pthread.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <winsock2.h>
/**
* Data associated with an open socket which uses the Windows Socket API.
*/
typedef struct guac_socket_wsa_data {
/**
* The associated Windows socket handle.
*/
SOCKET sock;
/**
* The number of bytes currently in the main write buffer.
*/
int written;
/**
* The main write buffer. Bytes written go here before being flushed
* to the open socket.
*/
char out_buf[GUAC_SOCKET_OUTPUT_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_wsa_data;
/**
* Writes the entire contents of the given buffer to the SOCKET handle
* associated with the given socket, retrying as necessary until the whole
* buffer is written, and aborting if an error occurs.
*
* @param socket
* The guac_socket associated with the SOCKET handle to which the given
* buffer should be written.
*
* @param buf
* The buffer of data to write to the given guac_socket.
*
* @param count
* The number of bytes within the given buffer.
*
* @return
* The number of bytes written, which will be exactly the size of the given
* buffer, or a negative value if an error occurs.
*/
ssize_t guac_socket_wsa_write(guac_socket* socket,
const void* buf, size_t count) {
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
const char* buffer = buf;
/* Write until completely written */
while (count > 0) {
int retval = send(data->sock, buffer, count, 0);
/* Record errors in guac_error */
if (retval < 0) {
guac_error = GUAC_STATUS_SEE_ERRNO;
guac_error_message = "Error writing data to socket";
return retval;
}
/* Advance buffer as data retval */
buffer += retval;
count -= retval;
}
return 0;
}
/**
* Attempts to read from the underlying SOCKET handle of the given guac_socket,
* populating the given buffer.
*
* @param socket
* The guac_socket being read from.
*
* @param buf
* The arbitrary buffer which we must populate with data.
*
* @param count
* The maximum number of bytes to read into the buffer.
*
* @return
* The number of bytes read, or -1 if an error occurs.
*/
static ssize_t guac_socket_wsa_read_handler(guac_socket* socket,
void* buf, size_t count) {
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Read from socket */
int retval = recv(data->sock, buf, count, 0);
/* Record errors in guac_error */
if (retval < 0) {
guac_error = GUAC_STATUS_SEE_ERRNO;
guac_error_message = "Error reading data from socket";
}
return retval;
}
/**
* 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_wsa_flush(guac_socket* socket) {
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Flush remaining bytes in buffer */
if (data->written > 0) {
/* Write ALL bytes in buffer immediately */
if (guac_socket_wsa_write(socket, data->out_buf, data->written))
return 1;
data->written = 0;
}
return 0;
}
/**
* Flushes the internal buffer of the given guac_socket, writing all data
* to the underlying SOCKET handle.
*
* @param socket
* The guac_socket to flush.
*
* @return
* Zero if the flush operation was successful, non-zero otherwise.
*/
static ssize_t guac_socket_wsa_flush_handler(guac_socket* socket) {
int retval;
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Acquire exclusive access to buffer */
pthread_mutex_lock(&(data->buffer_lock));
/* Flush contents of buffer */
retval = guac_socket_wsa_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_wsa_write_buffered(guac_socket* socket,
const void* buf, size_t count) {
size_t original_count = count;
const char* current = buf;
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Append to buffer, flush if necessary */
while (count > 0) {
int chunk_size;
int remaining = sizeof(data->out_buf) - data->written;
/* If no space left in buffer, flush and retry */
if (remaining == 0) {
/* Abort if error occurs during flush */
if (guac_socket_wsa_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->out_buf + 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_wsa_write_handler(guac_socket* socket,
const void* buf, size_t count) {
int retval;
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Acquire exclusive access to buffer */
pthread_mutex_lock(&(data->buffer_lock));
/* Write provided data to buffer */
retval = guac_socket_wsa_write_buffered(socket, buf, count);
/* Relinquish exclusive access to buffer */
pthread_mutex_unlock(&(data->buffer_lock));
return retval;
}
/**
* Waits for data on the underlying SOCKET handle of the given socket to
* become available such that the next read operation will not block.
*
* @param socket
* The guac_socket to wait for.
*
* @param usec_timeout
* The maximum amount of time to wait for data, in microseconds, or -1 to
* potentially wait forever.
*
* @return
* A positive value on success, zero if the timeout elapsed and no data is
* available, or a negative value if an error occurs.
*/
static int guac_socket_wsa_select_handler(guac_socket* socket,
int usec_timeout) {
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
fd_set sockets;
struct timeval timeout;
int retval;
/* Initialize fd_set with single underlying socket handle */
FD_ZERO(&sockets);
FD_SET(data->sock, &sockets);
/* No timeout if usec_timeout is negative */
if (usec_timeout < 0)
retval = select(0, &sockets, NULL, NULL, NULL);
/* Handle timeout if specified */
else {
timeout.tv_sec = usec_timeout / 1000000;
timeout.tv_usec = usec_timeout % 1000000;
retval = select(0, &sockets, NULL, NULL, &timeout);
}
/* Properly set guac_error */
if (retval < 0) {
guac_error = GUAC_STATUS_SEE_ERRNO;
guac_error_message = "Error while waiting for data on socket";
}
if (retval == 0) {
guac_error = GUAC_STATUS_TIMEOUT;
guac_error_message = "Timeout while waiting for data on socket";
}
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_wsa_free_handler(guac_socket* socket) {
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Destroy locks */
pthread_mutex_destroy(&(data->socket_lock));
pthread_mutex_destroy(&(data->buffer_lock));
/* Close socket */
closesocket(data->sock);
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_wsa_lock_handler(guac_socket* socket) {
guac_socket_wsa_data* data = (guac_socket_wsa_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_wsa_unlock_handler(guac_socket* socket) {
guac_socket_wsa_data* data = (guac_socket_wsa_data*) socket->data;
/* Relinquish exclusive access to socket */
pthread_mutex_unlock(&(data->socket_lock));
}
guac_socket* guac_socket_open_wsa(SOCKET sock) {
pthread_mutexattr_t lock_attributes;
/* Allocate socket and associated data */
guac_socket* socket = guac_socket_alloc();
guac_socket_wsa_data* data = malloc(sizeof(guac_socket_wsa_data));
/* Store socket as socket data */
data->sock = sock;
data->written = 0;
socket->data = data;
pthread_mutexattr_init(&lock_attributes);
pthread_mutexattr_setpshared(&lock_attributes, PTHREAD_PROCESS_SHARED);
/* Init locks */
pthread_mutex_init(&(data->socket_lock), &lock_attributes);
pthread_mutex_init(&(data->buffer_lock), &lock_attributes);
/* Set read/write handlers */
socket->read_handler = guac_socket_wsa_read_handler;
socket->write_handler = guac_socket_wsa_write_handler;
socket->select_handler = guac_socket_wsa_select_handler;
socket->lock_handler = guac_socket_wsa_lock_handler;
socket->unlock_handler = guac_socket_wsa_unlock_handler;
socket->flush_handler = guac_socket_wsa_flush_handler;
socket->free_handler = guac_socket_wsa_free_handler;
return socket;
}