mike-jumper commented on a change in pull request #297: URL: https://github.com/apache/guacamole-server/pull/297#discussion_r450558885
########## File path: src/libguac/argv.c ########## @@ -0,0 +1,350 @@ +/* + * 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/argv.h" +#include "guacamole/client.h" +#include "guacamole/protocol.h" +#include "guacamole/socket.h" +#include "guacamole/stream.h" +#include "guacamole/string.h" +#include "guacamole/user.h" + +#include <pthread.h> +#include <stdlib.h> +#include <string.h> + +/** + * The state of an argument that will be automatically processed. Note that + * this is distinct from the state of an argument value that is currently being + * processed. Argument value states are dynamically-allocated and scoped by the + * associated guac_stream. + */ +typedef struct guac_argv_state { + + /** + * The name of the argument. + */ + char name[GUAC_ARGV_MAX_NAME_LENGTH]; + + /** + * Whether at least one value for this argument has been received since it + * was registered. + */ + int received; + + /** + * Bitwise OR of all option flags that should affect processing of this + * argument. + */ + int options; + + /** + * The callback that should be invoked when a new value for the associated + * argument has been received. If the GUAC_ARGV_OPTION_ONCE flag is set, + * the callback will be invoked at most once. + */ + guac_argv_callback* callback; + + /** + * The arbitrary data that should be passed to the callback. + */ + void* data; + +} guac_argv_state; + +/** + * The current state of automatic processing of "argv" streams. + */ +typedef struct guac_argv_await_state { + + /** + * Whether automatic argument processing has been stopped via a call to + * guac_argv_stop(). + */ + int stopped; + + /** + * The total number of arguments registered. + */ + unsigned int num_registered; + + /** + * All registered arguments and their corresponding callbacks. + */ + guac_argv_state registered[GUAC_ARGV_MAX_REGISTERED]; + + /** + * Lock which protects multi-threaded access to this entire state + * structure, including the condition that signals specific modifications + * to the structure. + */ + pthread_mutex_t lock; + + /** + * Condition which is signalled whenever the overall state of "argv" + * processing changes, either through the receipt of a new argument value + * or due to a call to guac_argv_stop(). + */ + pthread_cond_t changed; + +} guac_argv_await_state; + +/** + * The value or current status of a connection parameter received over an + * "argv" stream. + */ +typedef struct guac_argv { + + /** + * The state of the specific setting being updated. + */ + guac_argv_state* state; + + /** + * The mimetype of the data being received. + */ + char mimetype[GUAC_ARGV_MAX_MIMETYPE_LENGTH]; + + /** + * Buffer space for containing the received argument value. + */ + char buffer[GUAC_ARGV_MAX_LENGTH]; + + /** + * The number of bytes received so far. + */ + int length; + +} guac_argv; + +/** + * Statically-allocated, shared state of the guac_argv_*() family of functions. + */ +static guac_argv_await_state await_state = { + .lock = PTHREAD_MUTEX_INITIALIZER, + .changed = PTHREAD_COND_INITIALIZER +}; + +/** + * Returns whether at least one value for each of the provided arguments has + * been received. + * + * @param args + * A NULL-terminated array of the names of all arguments to test. + * + * @return + * Non-zero if at least one value has been received for each of the + * provided arguments, zero otherwise. + */ +static int guac_argv_is_received(const char** args) { + + for (int i = 0; i < await_state.num_registered; i++) { + + /* Ignore all received arguments */ + guac_argv_state* state = &await_state.registered[i]; + if (state->received) + continue; + + /* Fail immediately for any matching non-received arguments */ + for (const char** arg = args; *arg != NULL; arg++) { + if (strcmp(state->name, *arg) == 0) + return 0; + } + + } + + /* All arguments were received */ + return 1; + +} + +int guac_argv_register(const char* name, guac_argv_callback* callback, void* data, int options) { + + pthread_mutex_lock(&await_state.lock); + + if (await_state.num_registered == GUAC_ARGV_MAX_REGISTERED) { + pthread_mutex_unlock(&await_state.lock); + return 1; + } + + guac_argv_state* state = &await_state.registered[await_state.num_registered++]; + guac_strlcpy(state->name, name, sizeof(state->name)); + state->options = options; + state->callback = callback; + state->data = data; + + pthread_mutex_unlock(&await_state.lock); + return 0; + +} + +int guac_argv_await(const char** args) { + + /* Wait for all requested arguments to be received (or for receipt to be + * stopped) */ + pthread_mutex_lock(&await_state.lock); + while (!await_state.stopped && !guac_argv_is_received(args)) + pthread_cond_wait(&await_state.changed, &await_state.lock); + + /* Arguments were successfully received only if receipt was not stopped */ + int retval = await_state.stopped; + pthread_mutex_unlock(&await_state.lock); + return retval; + +} + +/** + * Handler for "blob" instructions which appends the data from received blobs + * to the end of the in-progress argument value buffer. + * + * @see guac_user_blob_handler + */ +static int guac_argv_blob_handler(guac_user* user, guac_stream* stream, + void* data, int length) { + + guac_argv* argv = (guac_argv*) stream->data; + + /* Calculate buffer size remaining, including space for null terminator, + * adjusting received length accordingly */ + int remaining = sizeof(argv->buffer) - argv->length - 1; + if (length > remaining) + length = remaining; + + /* Append received data to end of buffer */ + memcpy(argv->buffer + argv->length, data, length); + argv->length += length; + + return 0; + +} + +/** + * Handler for "end" instructions which applies the changes specified by the + * argument value buffer associated with the stream. + * + * @see guac_user_end_handler + */ +static int guac_argv_end_handler(guac_user* user, guac_stream* stream) { + + int result = 0; + + /* Append null terminator to value */ + guac_argv* argv = (guac_argv*) stream->data; + argv->buffer[argv->length] = '\0'; + + pthread_mutex_lock(&await_state.lock); + + /* Invoke callback, limiting to a single invocation if + * GUAC_ARGV_OPTION_ONCE applies */ + guac_argv_state* state = argv->state; + if (!(state->options & GUAC_ARGV_OPTION_ONCE) || !state->received) { + if (state->callback != NULL) + result = state->callback(user, argv->mimetype, state->name, argv->buffer, state->data); + } + + /* Alert connected clients regarding newly-accepted values if echo is + * enabled */ + if (!result && (state->options & GUAC_ARGV_OPTION_ECHO)) { + guac_client* client = user->client; + guac_client_stream_argv(client, client->socket, argv->mimetype, state->name, argv->buffer); + } + + /* Notify that argument has been received */ + state->received = 1; + pthread_cond_broadcast(&await_state.changed); + + pthread_mutex_unlock(&await_state.lock); + + free(argv); + return 0; + +} + +int guac_argv_received(guac_stream* stream, const char* mimetype, const char* name) { + + pthread_mutex_lock(&await_state.lock); + + for (int i = 0; i < await_state.num_registered; i++) { + + /* Ignore any arguments that have already been received if they are + * declared as being acceptable only once */ + guac_argv_state* state = &await_state.registered[i]; + if ((state->options & GUAC_ARGV_OPTION_ONCE) && state->received) + continue; + + /* Argument matched */ + if (strcmp(state->name, name) == 0) { + + guac_argv* argv = malloc(sizeof(guac_argv)); + guac_strlcpy(argv->mimetype, mimetype, sizeof(argv->mimetype)); + argv->state = state; + argv->length = 0; + + stream->data = argv; + stream->blob_handler = guac_argv_blob_handler; + stream->end_handler = guac_argv_end_handler; + + pthread_mutex_unlock(&await_state.lock); + return 0; + + } + + } + + /* No such argument awaiting processing */ + pthread_mutex_unlock(&await_state.lock); + return 1; + +} + +void guac_argv_stop() { + pthread_mutex_lock(&await_state.lock); + + /* Signal any waiting threads that no further argument values will be + * received */ + if (!await_state.stopped) { + await_state.stopped = 1; + pthread_cond_broadcast(&await_state.changed); + + } + + pthread_mutex_unlock(&await_state.lock); +} + +int guac_argv_handler(guac_user* user, guac_stream* stream, + char* mimetype, char* name) { + + /* Refuse stream if not argument is not registered */ Review comment: You're not not not wrong. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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