/**
* mds — A micro-display server
* Copyright © 2014, 2015, 2016, 2017 Mattias Andrée (maandree@kth.se)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "sending.h"
#include "globals.h"
#include "client.h"
#include "queued-interception.h"
#include "multicast.h"
#include <libmdsserver/mds-message.h>
#include <libmdsserver/macros.h>
#include <libmdsserver/util.h>
#include <stddef.h>
#include <stdint.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
/**
* Get the client by its socket's file descriptor in a synchronised manner
*
* @param client_fd The file descriptor of the client's socket
* @return The client
*/
static client_t *
client_by_socket(int client_fd)
{
size_t address;
with_mutex (slave_mutex, address = fd_table_get(&client_map, client_fd););
return (client_t*)(void*)address;
}
/**
* Send a multicast message to one recipient
*
* @param multicast The message
* @param recipient The recipient
* @param modifying Whether the recipient may modify the message
* @return Evaluates to true if and only if the entire message was sent
*/
static int __attribute__((nonnull))
send_multicast_to_recipient(multicast_t *multicast, client_t *recipient, int modifying)
{
char *msg = multicast->message + multicast->message_ptr;
size_t n = multicast->message_length - multicast->message_ptr;
size_t sent;
/* Skip Modify ID header if the interceptors will not perform a modification. */
if (!modifying && !multicast->message_ptr) {
n -= multicast->message_prefix;
multicast->message_ptr += multicast->message_prefix;
}
/* Send the message. */
n *= sizeof(char);
with_mutex (recipient->mutex,
if (recipient->open) {
sent = send_message(recipient->socket_fd, msg + multicast->message_ptr, n);
n -= sent;
multicast->message_ptr += sent / sizeof(char);
if (n > 0 && errno != EINTR)
xperror(*argv);
}
);
return !n;
}
/**
* Wait for the recipient of a multicast to reply
*
* @param recipient The recipient
* @param modify_id The modify ID of the multicast
*/
static void __attribute__((nonnull))
wait_for_reply(client_t *recipient, uint64_t modify_id)
{
/* pthread_cond_timedwait is required to handle re-exec and termination because
pthread_cond_timedwait and pthread_cond_wait ignore interruptions via signals. */
struct timespec timeout = {
.tv_sec = 1,
.tv_nsec = 0
};
with_mutex_if (modify_mutex, !recipient->modify_message,
if (!hash_table_contains_key(&modify_map, (size_t)modify_id)) {
hash_table_put(&modify_map, (size_t)modify_id, (size_t)(void*)recipient);
pthread_cond_signal(&slave_cond);
}
);
with_mutex_if (recipient->modify_mutex, !recipient->modify_message,
while (!recipient->modify_message && !terminating)
pthread_cond_timedwait(&slave_cond, &slave_mutex, &timeout);
if (!terminating)
hash_table_remove(&modify_map, (size_t)modify_id);
);
}
/**
* Multicast a message
*
* @param multicast The multicast message
*/
void multicast_message(multicast_t *multicast)
{
int consumed = 0, modifying = 0;
uint64_t modify_id = 0;
size_t i, n = strlen("Modify ID: ");
char *value, *lf, *old_buf;
mds_message_t* mod;
client_t* client;
queued_interception_t client_;
if (startswith_n(multicast->message, "Modify ID: ", multicast->message_length, n)) {
value = multicast->message + n;
lf = strchr(value, '\n');
*lf = '\0';
modify_id = atou64(value);
*lf = '\n';
}
for (; multicast->interceptions_ptr < multicast->interceptions_count; multicast->interceptions_ptr++) {
client_ = multicast->interceptions[multicast->interceptions_ptr];
client = client_.client;
modifying = 0;
/* After unmarshalling at re-exec, client will be NULL and must be mapped from its socket. */
if (!client)
client_.client = client = client_by_socket(client_.socket_fd);
/* Send the message to the recipient. */
if (!send_multicast_to_recipient(multicast, client, client_.modifying)) {
/* Stop if we are re-exec:ing or terminating, or continue to next recipient on error. */
if (terminating)
return;
else
continue;
}
/* Do not wait for a reply if it is non-modifying. */
if (!client_.modifying) {
/* Reset how much of the message has been sent before we continue with next recipient. */
multicast->message_ptr = 0;
continue;
}
/* Wait for a reply. */
wait_for_reply(client, modify_id);
if (terminating)
return;
/* Act upon the reply. */
mod = client->modify_message;
for (i = 0; i < mod->header_count; i++) {
if (strequals(mod->headers[i], "Modify: yes")) {
modifying = 1;
consumed = mod->payload_size == 0;
break;
}
}
if (modifying && !consumed) {
n = mod->payload_size;
old_buf = multicast->message;
if (xrealloc(multicast->message, multicast->message_prefix + n, char)) {
xperror(*argv);
multicast->message = old_buf;
} else {
memcpy(multicast->message + multicast->message_prefix, mod->payload, n);
}
}
/* Free the reply. */
mds_message_destroy(client->modify_message);
/* Reset how much of the message has been sent before we continue with next recipient. */
multicast->message_ptr = 0;
if (consumed)
break;
}
}
/**
* Send the next message in a clients multicast queue
*
* @param client The client
*/
void
send_multicast_queue(client_t *client)
{
multicast_t multicast;
size_t c;
while (client->multicasts_count > 0) {
with_mutex_if (client->mutex, client->multicasts_count > 0,
c = (client->multicasts_count -= 1) * sizeof(multicast_t);
multicast = client->multicasts[0];
memmove(client->multicasts, client->multicasts + 1, c);
if (c == 0) {
free(client->multicasts);
client->multicasts = NULL;
}
);
multicast_message(&multicast);
multicast_destroy(&multicast);
}
}
/**
* Send the messages that are in a clients reply queue
*
* @param client The client
*/
void
send_reply_queue(client_t *client)
{
char *sendbuf = client->send_pending;
char *sendbuf_ = sendbuf;
size_t sent, n;
if (!client->send_pending_size)
return;
n = client->send_pending_size;
client->send_pending_size = 0;
client->send_pending = NULL;
with_mutex (client->mutex,
while (n > 0) {
sent = send_message(client->socket_fd, sendbuf_, n);
n -= sent;
sendbuf_ += sent / sizeof(char);
if (n > 0 && errno != EINTR) { /* Ignore EINTR */
xperror(*argv);
break;
}
}
free(sendbuf);
);
}
