/**
* coopgammad -- Cooperative gamma server
* Copyright (C) 2016 Mattias Andrée (maandree@kth.se)
*
* This library 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 library 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 library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "server.h"
#include "util.h"
#include <sys/select.h>
#include <sys/socket.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
/**
* List of all client's file descriptors
*
* Unused slots, with index less than `connections_used`,
* should have the value -1 (negative)
*/
int* connections = NULL;
/**
* The number of elements allocated for `connections`
*/
size_t connections_alloc = 0;
/**
* The index of the first unused slot in `connections`
*/
size_t connections_ptr = 0;
/**
* The index of the last used slot in `connections`, plus 1
*/
size_t connections_used = 0;
/**
* The clients' connections' message buffers
*/
struct message* client_messages = NULL;
/**
* The server socket's file descriptor
*/
extern int socketfd;
/**
* Has the process receive a signal
* telling it to re-execute?
*/
extern volatile sig_atomic_t reexec;
/**
* Has the process receive a signal
* telling it to terminate?
*/
extern volatile sig_atomic_t terminate;
/**
* Destroy the state of the connections
*
* @param disconnect Disconnect all connections?
*/
void server_destroy(int disconnect)
{
size_t i;
/* TODO */ (void) disconnect;
for (i = 0; i < connections_used; i++)
if (connections[i] >= 0)
message_destroy(client_messages + i);
free(client_messages);
free(connections);
}
/**
* Marshal the state of the connections
*
* @param buf Output buffer for the marshalled data,
* `NULL` to only measure how many bytes
* this buffer needs
* @return The number of marshalled bytes
*/
size_t server_marshal(void* buf)
{
size_t i, off = 0;
char* bs = buf;
if (bs != NULL)
*(size_t*)(bs + off) = connections_ptr;
off += sizeof(size_t);
if (bs != NULL)
*(size_t*)(bs + off) = connections_used;
off += sizeof(size_t);
if (bs != NULL)
memcpy(bs + off, connections, connections_used * sizeof(*connections));
off += connections_used * sizeof(*connections);
for (i = 0; i < connections_used; i++)
if (connections[i] >= 0)
off += message_marshal(client_messages + i, bs ? bs + off : NULL);
return off;
}
/**
* Unmarshal the state of the connections
*
* @param buf Buffer for the marshalled data
* @return The number of unmarshalled bytes, 0 on error
*/
size_t server_unmarshal(const void* buf)
{
size_t off = 0, i, n;
const char* bs = buf;
connections = NULL;
client_messages = NULL;
connections_ptr = *(const size_t*)(bs + off);
off += sizeof(size_t);
connections_alloc = connections_used = *(const size_t*)(bs + off);
off += sizeof(size_t);
if (connections_alloc > 0)
{
connections = memdup(bs + off, connections_alloc * sizeof(*connections));
if (connections == NULL)
return 0;
off += connections_used * sizeof(*connections);
client_messages = malloc(connections_alloc * sizeof(*client_messages));
if (client_messages == NULL)
return 0;
}
for (i = 0; i < connections_used; i++)
if (connections[i] >= 0)
{
off += n = message_unmarshal(client_messages + i, bs ? bs + off : NULL);
if (n == 0)
return 0;
}
return off;
}
/**
* Sets the file descriptor set that includes
* the server socket and all connections
*
* @param fds The file descritor set
* @return The highest set file descritor plus 1
*/
static int update_fdset(fd_set* fds)
{
int fdmax = socketfd;
size_t i;
FD_ZERO(fds);
FD_SET(socketfd, fds);
for (i = 0; i < connections_used; i++)
if (connections[i] >= 0)
{
FD_SET(connections[i], fds);
if (fdmax < connections[i])
fdmax = connections[i];
}
return fdmax + 1;
}
/**
* Handle event on the server socket
*
* @return 1: New connection accepted
* 0: Successful
* -1: Failure
*/
static int handle_server(void)
{
int fd;
fd = accept(socketfd, NULL, NULL);
if (fd < 0)
switch (errno)
{
case EINTR:
return 0;
case ECONNABORTED:
case EINVAL:
terminate = 1;
return 0;
default:
return -1;
}
if (connections_ptr == connections_alloc)
{
int* new;
new = realloc(connections, (connections_alloc + 10) * sizeof(*connections));
if (new == NULL)
return -1;
connections = new;
connections_alloc += 10;
}
connections[connections_ptr++] = fd;
while (connections_ptr < connections_used)
if (connections[connections_ptr] >= 0)
connections_ptr++;
if (connections_used < connections_ptr)
connections_used = connections_ptr;
return 1;
}
/**
* Handle event on a connection to a client
*
* @param conn The index of the connection
* @return 1: New connection accepted
* 0: Successful
* -1: Failure
*/
static int handle_connection(size_t conn)
{
/* TODO */
return 0;
}
/**
* The program's main loop
*
* @return Zero on success, -1 on error
*/
int main_loop(void)
{
fd_set fds_orig, fds_read, fds_ex;
int i, r, update, fdn = update_fdset(&fds_orig);
size_t j;
while (!reexec && !terminate)
{
memcpy(&fds_read, &fds_orig, sizeof(fd_set));
memcpy(&fds_ex, &fds_orig, sizeof(fd_set));
if (select(fdn, &fds_read, NULL, &fds_ex, NULL) < 0)
{
if (errno == EINTR)
continue;
return -1;
}
update = 0;
for (i = 0; i < fdn; i++)
if (FD_ISSET(i, &fds_read) || FD_ISSET(i, &fds_ex))
{
if (i == socketfd)
r = handle_server();
else
{
for (j = 0;; j++)
if (connections[j] == i)
break;
r = handle_connection(j);
}
switch (r)
{
case 0:
break;
case 1:
update = 1;
break;
default:
return -1;
}
}
if (update)
update_fdset(&fds_orig);
}
return 0;
}
