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/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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 "mds-registry.h"
#include "util.h"
#include "globals.h"
#include "registry.h"
#include <libmdsserver/macros.h>
#include <libmdsserver/hash-help.h>
#include <libmdsserver/linked-list.h>
#include <errno.h>
#include <stdio.h>
#define reconnect_to_display() -1
/**
* This variable should declared by the actual server implementation.
* It must be configured before `main` is invoked.
*
* This tells the server-base how to behave
*/
server_characteristics_t server_characteristics =
{
.require_privileges = 0,
.require_display = 1,
.require_respawn_info = 0,
.sanity_check_argc = 1,
.fork_for_safety = 0,
.danger_is_deadly = 0
};
/**
* This function will be invoked before `initialise_server` (if not re-exec:ing)
* or before `unmarshal_server` (if re-exec:ing)
*
* @return Non-zero on error
*/
int preinitialise_server(void)
{
int stage = 0;
fail_if ((errno = pthread_mutex_init(&slave_mutex, NULL))); stage++;
fail_if ((errno = pthread_cond_init(&slave_cond, NULL))); stage++;
linked_list_create(&slave_list, 2);
return 0;
pfail:
xperror(*argv);
if (stage >= 1) pthread_mutex_destroy(&slave_mutex);
if (stage >= 2) pthread_cond_destroy(&slave_cond);
return 1;
}
/**
* This function should initialise the server,
* and it not invoked after a re-exec.
*
* @return Non-zero on error
*/
int initialise_server(void)
{
const char* const message =
"Command: intercept\n"
"Message ID: 0\n"
"Length: 32\n"
"\n"
"Command: register\n"
"Client closed\n"
/* -- NEXT MESSAGE -- */
"Command: reregister\n"
"Message ID: 1\n"
"\n";
/* We are asking all servers to reregister their
protocols for two reasons:
1) The server would otherwise not get registrations
from servers started before this server.
2) If this server crashes we may miss registrations
that happen between the crash and the recovery.
*/
if (full_send(message, strlen(message)))
return 1;
if (hash_table_create_tuned(®_table, 32))
{
xperror(*argv);
hash_table_destroy(®_table, NULL, NULL);
return 1;
}
reg_table.key_comparator = (compare_func*)string_comparator;
reg_table.hasher = (hash_func*)string_hash;
fail_if (server_initialised() < 0);
fail_if (mds_message_initialise(&received));
return 0;
pfail:
xperror(*argv);
mds_message_destroy(&received);
return 1;
}
/**
* This function will be invoked after `initialise_server` (if not re-exec:ing)
* or after `unmarshal_server` (if re-exec:ing)
*
* @return Non-zero on error
*/
int postinitialise_server(void)
{
if (connected)
return 0;
if (reconnect_to_display())
{
mds_message_destroy(&received);
return 1;
}
connected = 1;
return 0;
}
/**
* Perform the server's mission
*
* @return Non-zero on error
*/
int master_loop(void)
{
int rc = 1, r;
while (!reexecing && !terminating)
{
if (danger)
{
danger = 0;
free(send_buffer), send_buffer = NULL;
send_buffer_size = 0;
with_mutex (slave_mutex, linked_list_pack(&slave_list););
}
if (r = mds_message_read(&received, socket_fd), r == 0)
if (r = handle_message(), r == 0)
continue;
if (r == -2)
{
eprint("corrupt message received, aborting.");
goto fail;
}
else if (errno == EINTR)
continue;
else
fail_if (errno != ECONNRESET);
eprint("lost connection to server.");
mds_message_destroy(&received);
mds_message_initialise(&received);
connected = 0;
if (reconnect_to_display())
goto fail;
connected = 1;
}
rc = 0;
goto fail;
pfail:
xperror(*argv);
fail:
/* Join with all slaves threads. */
with_mutex (slave_mutex,
while (running_slaves > 0)
pthread_cond_wait(&slave_cond, &slave_mutex););
if (rc || !reexecing)
{
hash_table_destroy(®_table, (free_func*)reg_table_free_key, (free_func*)reg_table_free_value);
mds_message_destroy(&received);
}
pthread_mutex_destroy(&slave_mutex);
pthread_cond_destroy(&slave_cond);
free(send_buffer);
return rc;
}
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