/**
* Allocate a new session for a new client of the specified service.
*
* Create the link to the router session by calling the newSession
* entry point of the router using the router instance of the
* service this session is part of.
*
* @param service The service this connection was established by
* @param client_dcb The client side DCB
* @return The newly created session or NULL if an error occured
*/
SESSION *
session_alloc(SERVICE *service, DCB *client_dcb)
{
SESSION *session;
session = (SESSION *)calloc(1, sizeof(SESSION));
ss_info_dassert(session != NULL, "Allocating memory for session failed.");
if (session == NULL)
{
char errbuf[STRERROR_BUFLEN];
MXS_ERROR("Failed to allocate memory for "
"session object due error %d, %s.",
errno,
strerror_r(errno, errbuf, sizeof(errbuf)));
return NULL;
}
#if defined(SS_DEBUG)
session->ses_chk_top = CHK_NUM_SESSION;
session->ses_chk_tail = CHK_NUM_SESSION;
#endif
session->ses_is_child = (bool) DCB_IS_CLONE(client_dcb);
spinlock_init(&session->ses_lock);
session->service = service;
session->client_dcb = client_dcb;
session->n_filters = 0;
memset(&session->stats, 0, sizeof(SESSION_STATS));
session->stats.connect = time(0);
session->state = SESSION_STATE_ALLOC;
/*<
* Associate the session to the client DCB and set the reference count on
* the session to indicate that there is a single reference to the
* session. There is no need to protect this or use atomic add as the
* session has not been made available to the other threads at this
* point.
*/
session->refcount = 1;
/*<
* This indicates that session is ready to be shared with backend
* DCBs. Note that this doesn't mean that router is initialized yet!
*/
session->state = SESSION_STATE_READY;
/*
* Only create a router session if we are not the listening
* DCB or an internal DCB. Creating a router session may create a connection to a
* backend server, depending upon the router module implementation
* and should be avoided for the listener session
*
* Router session creation may create other DCBs that link to the
* session, therefore it is important that the session lock is
* relinquished before the router call.
*/
if (client_dcb->state != DCB_STATE_LISTENING &&
client_dcb->dcb_role != DCB_ROLE_INTERNAL)
{
session->router_session = service->router->newSession(service->router_instance, session);
if (session->router_session == NULL)
{
session->state = SESSION_STATE_TO_BE_FREED;
MXS_ERROR("Failed to create new router session for service '%s'. "
"See previous errors for more details.", service->name);
}
/*
* Pending filter chain being setup set the head of the chain to
* be the router. As filters are inserted the current head will
* be pushed to the filter and the head updated.
*
* NB This dictates that filters are created starting at the end
* of the chain nearest the router working back to the client
* protocol end of the chain.
*/
session->head.instance = service->router_instance;
session->head.session = session->router_session;
session->head.routeQuery = (void *)(service->router->routeQuery);
session->tail.instance = session;
session->tail.session = session;
session->tail.clientReply = session_reply;
if (SESSION_STATE_TO_BE_FREED != session->state
&& service->n_filters > 0
&& !session_setup_filters(session))
{
session->state = SESSION_STATE_TO_BE_FREED;
MXS_ERROR("Setting up filters failed. "
"Terminating session %s.",
service->name);
}
}
if (SESSION_STATE_TO_BE_FREED != session->state)
{
session->state = SESSION_STATE_ROUTER_READY;
if (session->client_dcb->user == NULL)
{
MXS_INFO("Started session [%lu] for %s service ",
session->ses_id,
service->name);
}
else
{
MXS_INFO("Started %s client session [%lu] for '%s' from %s",
service->name,
session->ses_id,
session->client_dcb->user,
session->client_dcb->remote);
}
}
else
{
MXS_INFO("Start %s client session [%lu] for '%s' from %s failed, will be "
"closed as soon as all related DCBs have been closed.",
service->name,
session->ses_id,
session->client_dcb->user,
session->client_dcb->remote);
}
spinlock_acquire(&session_spin);
/** Assign a session id and increase, insert session into list */
session->ses_id = ++session_id;
session->next = allSessions;
allSessions = session;
spinlock_release(&session_spin);
atomic_add(&service->stats.n_sessions, 1);
atomic_add(&service->stats.n_current, 1);
CHK_SESSION(session);
client_dcb->session = session;
return SESSION_STATE_TO_BE_FREED == session->state ? NULL : session;
}
/**
* Allocate a new session for a new client of the specified service.
*
* Create the link to the router session by calling the newSession
* entry point of the router using the router instance of the
* service this session is part of.
*
* @param service The service this connection was established by
* @param client_dcb The client side DCB
* @return The newly created session or NULL if an error occured
*/
SESSION *
session_alloc(SERVICE *service, DCB *client_dcb)
{
SESSION *session;
session = (SESSION *)calloc(1, sizeof(SESSION));
ss_info_dassert(session != NULL,
"Allocating memory for session failed.");
if (session == NULL) {
int eno = errno;
errno = 0;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Failed to allocate memory for "
"session object due error %d, %s.",
eno,
strerror(eno))));
goto return_session;
}
#if defined(SS_DEBUG)
session->ses_chk_top = CHK_NUM_SESSION;
session->ses_chk_tail = CHK_NUM_SESSION;
#endif
spinlock_init(&session->ses_lock);
/*<
* Prevent backend threads from accessing before session is completely
* initialized.
*/
spinlock_acquire(&session->ses_lock);
session->service = service;
session->client = client_dcb;
session->n_filters = 0;
memset(&session->stats, 0, sizeof(SESSION_STATS));
session->stats.connect = time(0);
session->state = SESSION_STATE_ALLOC;
/*<
* Associate the session to the client DCB and set the reference count on
* the session to indicate that there is a single reference to the
* session. There is no need to protect this or use atomic add as the
* session has not been made available to the other threads at this
* point.
*/
session->data = client_dcb->data;
client_dcb->session = session;
session->refcount = 1;
/*<
* This indicates that session is ready to be shared with backend
* DCBs. Note that this doesn't mean that router is initialized yet!
*/
session->state = SESSION_STATE_READY;
/*< Release session lock */
spinlock_release(&session->ses_lock);
/*
* Only create a router session if we are not the listening
* DCB or an internal DCB. Creating a router session may create a connection to a
* backend server, depending upon the router module implementation
* and should be avoided for the listener session
*
* Router session creation may create other DCBs that link to the
* session, therefore it is important that the session lock is
* relinquished beforethe router call.
*/
if (client_dcb->state != DCB_STATE_LISTENING &&
client_dcb->dcb_role != DCB_ROLE_INTERNAL)
{
session->router_session =
service->router->newSession(service->router_instance,
session);
if (session->router_session == NULL) {
/**
* Inform other threads that session is closing.
*/
session->state = SESSION_STATE_STOPPING;
/*<
* Decrease refcount, set dcb's session pointer NULL
* and set session pointer to NULL.
*/
session_free(session);
client_dcb->session = NULL;
session = NULL;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Failed to create %s session.",
service->name)));
goto return_session;
}
/*
* Pending filter chain being setup set the head of the chain to
* be the router. As filters are inserted the current head will
* be pushed to the filter and the head updated.
*
* NB This dictates that filters are created starting at the end
* of the chain nearest the router working back to the client
* protocol end of the chain.
*/
session->head.instance = service->router_instance;
session->head.session = session->router_session;
session->head.routeQuery = (void *)(service->router->routeQuery);
session->tail.instance = session;
session->tail.session = session;
session->tail.clientReply = session_reply;
if (service->n_filters > 0)
{
if (!session_setup_filters(session))
{
/**
* Inform other threads that session is closing.
*/
session->state = SESSION_STATE_STOPPING;
/*<
* Decrease refcount, set dcb's session pointer NULL
* and set session pointer to NULL.
*/
session_free(session);
client_dcb->session = NULL;
session = NULL;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Failed to create %s session.",
service->name)));
goto return_session;
}
}
}
spinlock_acquire(&session_spin);
if (session->state != SESSION_STATE_READY)
{
session_free(session);
client_dcb->session = NULL;
session = NULL;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Failed to create %s session.",
service->name)));
spinlock_release(&session_spin);
}
else
{
session->state = SESSION_STATE_ROUTER_READY;
session->next = allSessions;
allSessions = session;
spinlock_release(&session_spin);
atomic_add(&service->stats.n_sessions, 1);
atomic_add(&service->stats.n_current, 1);
CHK_SESSION(session);
}
return_session:
return session;
}
