/* * This file is distributed as part of the MariaDB Corporation MaxScale. It 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, * version 2. * * 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, write to the Free Software Foundation, Inc., 51 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * * Copyright MariaDB Corporation Ab 2013-2014 */ /** * @file dcb.c - Descriptor Control Block generic functions * * Descriptor control blocks provide the key mechanism for the interface * with the non-blocking socket polling routines. The descriptor control * block is the user data that is handled by the epoll system and contains * the state data and pointers to other components that relate to the * use of a file descriptor. * * @verbatim * Revision History * * Date Who Description * 12/06/13 Mark Riddoch Initial implementation * 21/06/13 Massimiliano Pinto free_dcb is used * 25/06/13 Massimiliano Pinto Added checks to session and router_session * 28/06/13 Mark Riddoch Changed the free mechanism to * introduce a zombie state for the * dcb * 02/07/2013 Massimiliano Pinto Addition of delayqlock, delayq and * authlock for handling backend * asynchronous protocol connection * and a generic lock for backend * authentication * 16/07/2013 Massimiliano Pinto Added command type for dcb * 23/07/2013 Mark Riddoch Tidy up logging * 02/09/2013 Massimiliano Pinto Added session refcount * 27/09/2013 Massimiliano Pinto dcb_read returns 0 if ioctl returns no * error and 0 bytes to read. * This fixes a bug with many reads from * backend * 07/05/2014 Mark Riddoch Addition of callback mechanism * 20/06/2014 Mark Riddoch Addition of dcb_clone * * @endverbatim */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** Defined in log_manager.cc */ extern int lm_enabled_logfiles_bitmask; extern size_t log_ses_count[]; extern __thread log_info_t tls_log_info; static DCB *allDCBs = NULL; /* Diagnostics need a list of DCBs */ static DCB *zombies = NULL; static SPINLOCK dcbspin = SPINLOCK_INIT; static SPINLOCK zombiespin = SPINLOCK_INIT; static void dcb_final_free(DCB *dcb); static bool dcb_set_state_nomutex( DCB* dcb, const dcb_state_t new_state, dcb_state_t* old_state); static void dcb_call_callback(DCB *dcb, DCB_REASON reason); static DCB* dcb_get_next (DCB* dcb); static int dcb_null_write(DCB *dcb, GWBUF *buf); static int dcb_null_close(DCB *dcb); static int dcb_null_auth(DCB *dcb, SERVER *server, SESSION *session, GWBUF *buf); static int dcb_isvalid_nolock(DCB *dcb); size_t dcb_get_session_id( DCB* dcb) { size_t rval; if (dcb != NULL && dcb->session != NULL) { rval = dcb->session->ses_id; } else { rval = 0; } return rval; } /** * Read log info from session through DCB and store values to memory locations * passed as parameters. * * @param dcb DCB * @param sesid location where session id is to be copied * @param enabled_logs bit field indicating which log types are enabled for the * session * *@return true if call arguments included memory addresses, false if any of the *parameters was NULL. */ bool dcb_get_ses_log_info( DCB* dcb, size_t* sesid, int* enabled_logs) { bool succp; if (dcb == NULL || dcb->session == NULL || sesid == NULL || enabled_logs == NULL) { succp = false; } else { *sesid = dcb->session->ses_id; *enabled_logs = dcb->session->ses_enabled_logs; succp = true; } return succp; } /** * Return the pointer to the list of zombie DCB's * * @return Zombies DCB list */ DCB * dcb_get_zombies(void) { return zombies; } /** * Allocate a new DCB. * * This routine performs the generic initialisation on the DCB before returning * the newly allocated DCB. * * @return A newly allocated DCB or NULL if non could be allocated. */ DCB * dcb_alloc(dcb_role_t role) { DCB *rval; if ((rval = calloc(1, sizeof(DCB))) == NULL) { return NULL; } #if defined(SS_DEBUG) rval->dcb_chk_top = CHK_NUM_DCB; rval->dcb_chk_tail = CHK_NUM_DCB; #endif rval->dcb_errhandle_called = false; rval->dcb_role = role; spinlock_init(&rval->dcb_initlock); spinlock_init(&rval->writeqlock); spinlock_init(&rval->delayqlock); spinlock_init(&rval->authlock); spinlock_init(&rval->cb_lock); spinlock_init(&rval->pollinlock); spinlock_init(&rval->polloutlock); rval->pollinbusy = 0; rval->readcheck = 0; rval->polloutbusy = 0; rval->writecheck = 0; rval->fd = DCBFD_CLOSED; rval->evq.next = NULL; rval->evq.prev = NULL; rval->evq.pending_events = 0; rval->evq.processing = 0; spinlock_init(&rval->evq.eventqlock); memset(&rval->stats, 0, sizeof(DCBSTATS)); // Zero the statistics rval->state = DCB_STATE_ALLOC; bitmask_init(&rval->memdata.bitmask); rval->writeqlen = 0; rval->high_water = 0; rval->low_water = 0; rval->next = NULL; rval->callbacks = NULL; rval->data = NULL; rval->remote = NULL; rval->user = NULL; rval->flags = 0; spinlock_acquire(&dcbspin); if (allDCBs == NULL) allDCBs = rval; else { DCB *ptr = allDCBs; while (ptr->next) ptr = ptr->next; ptr->next = rval; } spinlock_release(&dcbspin); return rval; } /** * Free a DCB that has not been associated with a descriptor. * * @param dcb The DCB to free */ void dcb_free(DCB *dcb) { if (dcb->fd == DCBFD_CLOSED) { dcb_final_free(dcb); } else { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Attempt to free a DCB via dcb_free " "that has been associated with a descriptor."))); } } /** * Add the DCB to the end of zombies list. * * Adding to list occurs once per DCB. This is ensured by changing the * state of DCB to DCB_STATE_ZOMBIE after addition. Prior insertion, DCB state * is checked and operation proceeds only if state differs from DCB_STATE_ZOMBIE. * @param dcb The DCB to add to the zombie list * @return none */ void dcb_add_to_zombieslist(DCB *dcb) { bool succp = false; dcb_state_t prev_state = DCB_STATE_UNDEFINED; CHK_DCB(dcb); /*< * Protect zombies list access. */ spinlock_acquire(&zombiespin); /*< * If dcb is already added to zombies list, return. */ if (dcb->state != DCB_STATE_NOPOLLING) { ss_dassert(dcb->state != DCB_STATE_POLLING && dcb->state != DCB_STATE_LISTENING); spinlock_release(&zombiespin); return; } /*< * Add closing dcb to the top of the list. */ dcb->memdata.next = zombies; zombies = dcb; /*< * Set state which indicates that it has been added to zombies * list. */ succp = dcb_set_state(dcb, DCB_STATE_ZOMBIE, &prev_state); ss_info_dassert(succp, "Failed to set DCB_STATE_ZOMBIE"); spinlock_release(&zombiespin); } /* * Clone a DCB for internal use, mostly used for specialist filters * to create dummy clients based on real clients. * * @param orig The DCB to clone * @return A DCB that can be used as a client */ DCB * dcb_clone(DCB *orig) { DCB *clone; if ((clone = dcb_alloc(DCB_ROLE_REQUEST_HANDLER)) == NULL) { return NULL; } clone->fd = DCBFD_CLOSED; clone->flags |= DCBF_CLONE; clone->state = orig->state; clone->data = orig->data; if (orig->remote) clone->remote = strdup(orig->remote); if (orig->user) clone->user = strdup(orig->user); clone->protocol = orig->protocol; clone->func.write = dcb_null_write; /** * Close triggers closing of router session as well which is needed. */ clone->func.close = orig->func.close; clone->func.auth = dcb_null_auth; return clone; } /** * Free a DCB and remove it from the chain of all DCBs * * NB This is called with the caller holding the zombie queue * spinlock * * @param dcb The DCB to free */ static void dcb_final_free(DCB *dcb) { DCB_CALLBACK *cb; CHK_DCB(dcb); ss_info_dassert(dcb->state == DCB_STATE_DISCONNECTED || dcb->state == DCB_STATE_ALLOC, "dcb not in DCB_STATE_DISCONNECTED not in DCB_STATE_ALLOC state."); if (DCB_POLL_BUSY(dcb)) { /* Check if DCB has outstanding poll events */ LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "dcb_final_free: DCB %p has outstanding events", dcb))); } /*< First remove this DCB from the chain */ spinlock_acquire(&dcbspin); if (allDCBs == dcb) { /*< * Deal with the special case of removing the DCB at the head of * the chain. */ allDCBs = dcb->next; } else { /*< * We find the DCB that point to the one we are removing and then * set the next pointer of that DCB to the next pointer of the * DCB we are removing. */ DCB *ptr = allDCBs; while (ptr && ptr->next != dcb) ptr = ptr->next; if (ptr) ptr->next = dcb->next; } spinlock_release(&dcbspin); if (dcb->session) { /*< * Terminate client session. */ { SESSION *local_session = dcb->session; dcb->session = NULL; CHK_SESSION(local_session); /** * Set session's client pointer NULL so that other threads * won't try to call dcb_close for client DCB * after this call. */ if (local_session->client == dcb) { spinlock_acquire(&local_session->ses_lock); local_session->client = NULL; spinlock_release(&local_session->ses_lock); } session_free(local_session); } } if (dcb->protocol && (!DCB_IS_CLONE(dcb))) free(dcb->protocol); if (dcb->remote) free(dcb->remote); if (dcb->user) free(dcb->user); /* Clear write and read buffers */ if (dcb->delayq) { GWBUF *queue = dcb->delayq; while ((queue = gwbuf_consume(queue, GWBUF_LENGTH(queue))) != NULL); } if (dcb->dcb_readqueue) { GWBUF* queue = dcb->dcb_readqueue; while ((queue = gwbuf_consume(queue, GWBUF_LENGTH(queue))) != NULL); } spinlock_acquire(&dcb->cb_lock); while ((cb = dcb->callbacks) != NULL) { dcb->callbacks = cb->next; free(cb); } spinlock_release(&dcb->cb_lock); bitmask_free(&dcb->memdata.bitmask); free(dcb); } /** * Process the DCB zombie queue * * This routine is called by each of the polling threads with * the thread id of the polling thread. It must clear the bit in * the memdata bitmask for the polling thread that calls it. If the * operation of clearing this bit means that no bits are set in * the memdata.bitmask then the DCB is no longer able to be * referenced and it can be finally removed. * * @param threadid The thread ID of the caller */ DCB * dcb_process_zombies(int threadid) { DCB *ptr, *lptr; DCB* dcb_list = NULL; DCB* dcb = NULL; bool succp = false; /** * Perform a dirty read to see if there is anything in the queue. * This avoids threads hitting the queue spinlock when the queue * is empty. This will really help when the only entry is being * freed, since the queue is updated before the expensive call to * dcb_final_free. */ if (!zombies) return NULL; /* * Process the zombie queue and create a list of DCB's that can be * finally freed. This processing is down under a spinlock that * will prevent new entries being added to the zombie queue. Therefore * we do not want to do any expensive operations under this spinlock * as it will block other threads. The expensive operations will be * performed on the victim queue within holding the zombie queue * spinlock. */ spinlock_acquire(&zombiespin); ptr = zombies; lptr = NULL; while (ptr) { CHK_DCB(ptr); /* * Skip processing of DCB's that are * in the event queue waiting to be processed. */ if (ptr->evq.next || ptr->evq.prev) { lptr = ptr; ptr = ptr->memdata.next; } else { bitmask_clear(&ptr->memdata.bitmask, threadid); if (bitmask_isallclear(&ptr->memdata.bitmask)) { /** * Remove the DCB from the zombie queue * and call the final free routine for the * DCB * * ptr is the DCB we are processing * lptr is the previous DCB on the zombie queue * or NULL if the DCB is at the head of the * queue tptr is the DCB after the one we are * processing on the zombie queue */ DCB *tptr = ptr->memdata.next; if (lptr == NULL) zombies = tptr; else lptr->memdata.next = tptr; LOGIF(LD, (skygw_log_write_flush( LOGFILE_DEBUG, "%lu [dcb_process_zombies] Remove dcb " "%p fd %d " "in state %s from the " "list of zombies.", pthread_self(), ptr, ptr->fd, STRDCBSTATE(ptr->state)))); ss_info_dassert(ptr->state == DCB_STATE_ZOMBIE, "dcb not in DCB_STATE_ZOMBIE state."); /*< * Move dcb to linked list of victim dcbs. */ if (dcb_list == NULL) { dcb_list = ptr; dcb = dcb_list; } else { dcb->memdata.next = ptr; dcb = dcb->memdata.next; } dcb->memdata.next = NULL; ptr = tptr; } else { lptr = ptr; ptr = ptr->memdata.next; } } } spinlock_release(&zombiespin); /* * Process the victim queue. These are DCBs that are not in * use by any thread. * The corresponding file descriptor is closed, the DCB marked * as disconnected and the DCB itself is fianlly freed. */ dcb = dcb_list; while (dcb != NULL) { DCB* dcb_next = NULL; int rc = 0; if (dcb->fd > 0) { /*< * Close file descriptor and move to clean-up phase. */ rc = close(dcb->fd); if (rc < 0) { int eno = errno; errno = 0; LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Failed to close " "socket %d on dcb %p due error %d, %s.", dcb->fd, dcb, eno, strerror(eno)))); } else { dcb->fd = DCBFD_CLOSED; LOGIF(LD, (skygw_log_write_flush( LOGFILE_DEBUG, "%lu [dcb_process_zombies] Closed socket " "%d on dcb %p.", pthread_self(), dcb->fd, dcb))); #if defined(FAKE_CODE) conn_open[dcb->fd] = false; #endif /* FAKE_CODE */ } } LOGIF_MAYBE(LT, (dcb_get_ses_log_info( dcb, &tls_log_info.li_sesid, &tls_log_info.li_enabled_logs))); succp = dcb_set_state(dcb, DCB_STATE_DISCONNECTED, NULL); ss_dassert(succp); dcb_next = dcb->memdata.next; dcb_final_free(dcb); dcb = dcb_next; } /** Reset threads session data */ LOGIF(LT, tls_log_info.li_sesid = 0); return zombies; } /** * Connect to a server * * This routine will create a server connection * If succesful the new dcb will be put in * epoll set by dcb->func.connect * * @param server The server to connect to * @param session The session this connection is being made for * @param protocol The protocol module to use * @return The new allocated dcb or NULL if the DCB was not connected */ DCB * dcb_connect(SERVER *server, SESSION *session, const char *protocol) { DCB *dcb; GWPROTOCOL *funcs; int fd; int rc; if ((dcb = dcb_alloc(DCB_ROLE_REQUEST_HANDLER)) == NULL) { return NULL; } if ((funcs = (GWPROTOCOL *)load_module(protocol, MODULE_PROTOCOL)) == NULL) { dcb_set_state(dcb, DCB_STATE_DISCONNECTED, NULL); dcb_final_free(dcb); LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Failed to load protocol module for %s, free " "dcb %p\n", protocol, dcb))); return NULL; } memcpy(&(dcb->func), funcs, sizeof(GWPROTOCOL)); /** * Link dcb to session. Unlink is called in dcb_final_free */ if (!session_link_dcb(session, dcb)) { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_connect] Failed to link to session, the " "session has been removed.", pthread_self()))); dcb_final_free(dcb); return NULL; } fd = dcb->func.connect(dcb, server, session); if (fd == DCBFD_CLOSED) { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_connect] Failed to connect to server %s:%d, " "from backend dcb %p, client dcp %p fd %d.", pthread_self(), server->name, server->port, dcb, session->client, session->client->fd))); dcb_set_state(dcb, DCB_STATE_DISCONNECTED, NULL); dcb_final_free(dcb); return NULL; } else { LOGIF(LD, (skygw_log_write_flush( LOGFILE_DEBUG, "%lu [dcb_connect] Connected to server %s:%d, " "from backend dcb %p, client dcp %p fd %d.", pthread_self(), server->name, server->port, dcb, session->client, session->client->fd))); } ss_dassert(dcb->fd == DCBFD_CLOSED); /*< must be uninitialized at this point */ /** * Successfully connected to backend. Assign file descriptor to dcb */ dcb->fd = fd; /** * Add server pointer to dcb */ dcb->server = server; /** Copy status field to DCB */ dcb->dcb_server_status = server->status; ss_debug(dcb->dcb_port = server->port;) /** * backend_dcb is connected to backend server, and once backend_dcb * is added to poll set, authentication takes place as part of * EPOLLOUT event that will be received once the connection * is established. */ /** * Add the dcb in the poll set */ rc = poll_add_dcb(dcb); if (rc == DCBFD_CLOSED) { dcb_set_state(dcb, DCB_STATE_DISCONNECTED, NULL); dcb_final_free(dcb); return NULL; } /** * The dcb will be addded into poll set by dcb->func.connect */ atomic_add(&server->stats.n_connections, 1); atomic_add(&server->stats.n_current, 1); return dcb; } /** * General purpose read routine to read data from a socket in the * Descriptor Control Block and append it to a linked list of buffers. * The list may be empty, in which case *head == NULL * * @param dcb The DCB to read from * @param head Pointer to linked list to append data to * @return -1 on error, otherwise the number of read bytes on the last * iteration of while loop. 0 is returned if no data available. */ int dcb_read( DCB *dcb, GWBUF **head) { GWBUF *buffer = NULL; int b; int rc; int n; int nread = 0; CHK_DCB(dcb); if (dcb->fd <= 0) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Read failed, dcb is %s.", dcb->fd == DCBFD_CLOSED ? "closed" : "cloned, not readable"))); n = 0; goto return_n; } while (true) { int bufsize; rc = ioctl(dcb->fd, FIONREAD, &b); if (rc == -1) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : ioctl FIONREAD for dcb %p in " "state %s fd %d failed due error %d, %s.", dcb, STRDCBSTATE(dcb->state), dcb->fd, errno, strerror(errno)))); n = -1; goto return_n; } if (b == 0 && nread == 0) { /** Handle closed client socket */ if (dcb_isclient(dcb)) { char c; int l_errno = 0; int r = -1; /* try to read 1 byte, without consuming the socket buffer */ r = recv(dcb->fd, &c, sizeof(char), MSG_PEEK); l_errno = errno; if (r <= 0 && l_errno != EAGAIN && l_errno != EWOULDBLOCK && l_errno != 0) { n = -1; goto return_n; } } n = 0; goto return_n; } else if (b == 0) { n = 0; goto return_n; } dcb->last_read = hkheartbeat; bufsize = MIN(b, MAX_BUFFER_SIZE); if ((buffer = gwbuf_alloc(bufsize)) == NULL) { /*< * This is a fatal error which should cause shutdown. * Todo shutdown if memory allocation fails. */ LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Failed to allocate read buffer " "for dcb %p fd %d, due %d, %s.", dcb, dcb->fd, errno, strerror(errno)))); n = -1; goto return_n; } GW_NOINTR_CALL(n = read(dcb->fd, GWBUF_DATA(buffer), bufsize); dcb->stats.n_reads++); if (n <= 0) { if (errno != 0 && errno != EAGAIN && errno != EWOULDBLOCK) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Read failed, dcb %p in state " "%s fd %d, due %d, %s.", dcb, STRDCBSTATE(dcb->state), dcb->fd, errno, strerror(errno)))); } gwbuf_free(buffer); goto return_n; } nread += n; LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_read] Read %d bytes from dcb %p in state %s " "fd %d.", pthread_self(), n, dcb, STRDCBSTATE(dcb->state), dcb->fd))); /*< Append read data to the gwbuf */ *head = gwbuf_append(*head, buffer); } /*< while (true) */ return_n: return n; } /** * General purpose routine to write to a DCB * * @param dcb The DCB of the client * @param queue Queue of buffers to write */ int dcb_write(DCB *dcb, GWBUF *queue) { int w; int saved_errno = 0; int below_water; below_water = (dcb->high_water && dcb->writeqlen < dcb->high_water) ? 1 : 0; ss_dassert(queue != NULL); if (dcb->fd <= 0) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Write failed, dcb is %s.", dcb->fd == DCBFD_CLOSED ? "closed" : "cloned, not writable"))); return 0; } /** * SESSION_STATE_STOPPING means that one of the backends is closing * the router session. Some backends may have not completed * authentication yet and thus they have no information about router * being closed. Session state is changed to SESSION_STATE_STOPPING * before router's closeSession is called and that tells that DCB may * still be writable. */ if (queue == NULL || (dcb->state != DCB_STATE_ALLOC && dcb->state != DCB_STATE_POLLING && dcb->state != DCB_STATE_LISTENING && dcb->state != DCB_STATE_NOPOLLING && (dcb->session == NULL || dcb->session->state != SESSION_STATE_STOPPING))) { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_write] Write aborted to dcb %p because " "it is in state %s", pthread_self(), dcb->stats.n_buffered, dcb, STRDCBSTATE(dcb->state), dcb->fd))); //ss_dassert(false); return 0; } spinlock_acquire(&dcb->writeqlock); if (dcb->writeq != NULL) { /* * We have some queued data, so add our data to * the write queue and return. * The assumption is that there will be an EPOLLOUT * event to drain what is already queued. We are protected * by the spinlock, which will also be acquired by the * the routine that drains the queue data, so we should * not have a race condition on the event. */ if (queue) { int qlen; qlen = gwbuf_length(queue); atomic_add(&dcb->writeqlen, qlen); dcb->writeq = gwbuf_append(dcb->writeq, queue); dcb->stats.n_buffered++; LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_write] Append to writequeue. %d writes " "buffered for dcb %p in state %s fd %d", pthread_self(), dcb->stats.n_buffered, dcb, STRDCBSTATE(dcb->state), dcb->fd))); } } else { /* * Loop over the buffer chain that has been passed to us * from the reading side. * Send as much of the data in that chain as possible and * add any balance to the write queue. */ while (queue != NULL) { int qlen; #if defined(FAKE_CODE) if (dcb->dcb_role == DCB_ROLE_REQUEST_HANDLER && dcb->session != NULL) { if (dcb_isclient(dcb) && fail_next_client_fd) { dcb_fake_write_errno[dcb->fd] = 32; dcb_fake_write_ev[dcb->fd] = 29; fail_next_client_fd = false; } else if (!dcb_isclient(dcb) && fail_next_backend_fd) { dcb_fake_write_errno[dcb->fd] = 32; dcb_fake_write_ev[dcb->fd] = 29; fail_next_backend_fd = false; } } #endif /* FAKE_CODE */ qlen = GWBUF_LENGTH(queue); GW_NOINTR_CALL( w = gw_write(dcb, GWBUF_DATA(queue), qlen); dcb->stats.n_writes++; ); if (w < 0) { saved_errno = errno; errno = 0; if (LOG_IS_ENABLED(LOGFILE_DEBUG)) { if (saved_errno == EPIPE) { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_write] Write to dcb " "%p in state %s fd %d failed " "due errno %d, %s", pthread_self(), dcb, STRDCBSTATE(dcb->state), dcb->fd, saved_errno, strerror(saved_errno)))); } } if (LOG_IS_ENABLED(LOGFILE_ERROR)) { if (saved_errno != EPIPE && saved_errno != EAGAIN && saved_errno != EWOULDBLOCK) { LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Write to dcb %p in " "state %s fd %d failed due " "errno %d, %s", dcb, STRDCBSTATE(dcb->state), dcb->fd, saved_errno, strerror(saved_errno)))); } } break; } /* * Pull the number of bytes we have written from * queue with have. */ queue = gwbuf_consume(queue, w); LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_write] Wrote %d Bytes to dcb %p in " "state %s fd %d", pthread_self(), w, dcb, STRDCBSTATE(dcb->state), dcb->fd))); } /*< while (queue != NULL) */ /*< * What wasn't successfully written is stored to write queue * for suspended write. */ dcb->writeq = queue; if (queue) { int qlen; qlen = gwbuf_length(queue); atomic_add(&dcb->writeqlen, qlen); dcb->stats.n_buffered++; } } /* if (dcb->writeq) */ if (saved_errno != 0 && queue != NULL && saved_errno != EAGAIN && saved_errno != EWOULDBLOCK) { bool dolog = true; /** * Do not log if writing COM_QUIT to backend failed. */ if (GWBUF_IS_TYPE_MYSQL(queue)) { uint8_t* data = GWBUF_DATA(queue); if (data[4] == 0x01) { dolog = false; } } if (dolog) { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_write] Writing to %s socket failed due %d, %s.", pthread_self(), dcb_isclient(dcb) ? "client" : "backend server", saved_errno, strerror(saved_errno)))); } spinlock_release(&dcb->writeqlock); return 0; } spinlock_release(&dcb->writeqlock); if (dcb->high_water && dcb->writeqlen > dcb->high_water && below_water) { atomic_add(&dcb->stats.n_high_water, 1); dcb_call_callback(dcb, DCB_REASON_HIGH_WATER); } return 1; } /** * Drain the write queue of a DCB. This is called as part of the EPOLLOUT handling * of a socket and will try to send any buffered data from the write queue * up until the point the write would block. * * @param dcb DCB to drain the write queue of * @return The number of bytes written */ int dcb_drain_writeq(DCB *dcb) { int n = 0; int w; int saved_errno = 0; int above_water; above_water = (dcb->low_water && dcb->writeqlen > dcb->low_water) ? 1 : 0; spinlock_acquire(&dcb->writeqlock); if (dcb->writeq) { int len; /* * Loop over the buffer chain in the pending writeq * Send as much of the data in that chain as possible and * leave any balance on the write queue. */ while (dcb->writeq != NULL) { len = GWBUF_LENGTH(dcb->writeq); GW_NOINTR_CALL(w = gw_write(dcb, GWBUF_DATA(dcb->writeq), len);); saved_errno = errno; errno = 0; if (w < 0) { #if defined(SS_DEBUG) if (saved_errno == EAGAIN || saved_errno == EWOULDBLOCK) #else if (saved_errno == EAGAIN || saved_errno == EWOULDBLOCK || saved_errno == EPIPE) #endif { break; } LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Write to dcb %p " "in state %s fd %d failed due errno %d, %s", dcb, STRDCBSTATE(dcb->state), dcb->fd, saved_errno, strerror(saved_errno)))); break; } /* * Pull the number of bytes we have written from * queue with have. */ dcb->writeq = gwbuf_consume(dcb->writeq, w); LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_drain_writeq] Wrote %d Bytes to dcb %p " "in state %s fd %d", pthread_self(), w, dcb, STRDCBSTATE(dcb->state), dcb->fd))); n += w; } } spinlock_release(&dcb->writeqlock); atomic_add(&dcb->writeqlen, -n); /* The write queue has drained, potentially need to call a callback function */ if (dcb->writeq == NULL) dcb_call_callback(dcb, DCB_REASON_DRAINED); if (above_water && dcb->writeqlen < dcb->low_water) { atomic_add(&dcb->stats.n_low_water, 1); dcb_call_callback(dcb, DCB_REASON_LOW_WATER); } return n; } /** * Removes dcb from poll set, and adds it to zombies list. As a consequense, * dcb first moves to DCB_STATE_NOPOLLING, and then to DCB_STATE_ZOMBIE state. * At the end of the function state may not be DCB_STATE_ZOMBIE because once * dcb_initlock is released parallel threads may change the state. * * Parameters: * @param dcb The DCB to close * * */ void dcb_close(DCB *dcb) { int rc = 0; CHK_DCB(dcb); LOGIF(LD, (skygw_log_write(LOGFILE_DEBUG, "%lu [dcb_close]", pthread_self()))); /** * dcb_close may be called for freshly created dcb, in which case * it only needs to be freed. */ if (dcb->state == DCB_STATE_ALLOC) { dcb_set_state(dcb, DCB_STATE_DISCONNECTED, NULL); dcb_final_free(dcb); return; } ss_dassert(dcb->state == DCB_STATE_POLLING || dcb->state == DCB_STATE_NOPOLLING || dcb->state == DCB_STATE_ZOMBIE); /*< * Stop dcb's listening and modify state accordingly. */ if (dcb->state == DCB_STATE_POLLING) { rc = poll_remove_dcb(dcb); if (rc == 0) { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_close] Removed dcb %p in state %s from " "poll set.", pthread_self(), dcb, STRDCBSTATE(dcb->state)))); } else { LOGIF(LE, (skygw_log_write( LOGFILE_ERROR, "Error : Removing DCB fd == %d in state %s from " "poll set failed.", dcb->fd, STRDCBSTATE(dcb->state)))); } if (rc == 0) { /** * close protocol and router session */ if (dcb->func.close != NULL) { dcb->func.close(dcb); } /** Call possible callback for this DCB in case of close */ dcb_call_callback(dcb, DCB_REASON_CLOSE); if (dcb->state == DCB_STATE_NOPOLLING) { dcb_add_to_zombieslist(dcb); } } ss_dassert(dcb->state == DCB_STATE_NOPOLLING || dcb->state == DCB_STATE_ZOMBIE); } } /** * Diagnostic to print a DCB * * @param dcb The DCB to print * */ void printDCB(DCB *dcb) { printf("DCB: %p\n", (void *)dcb); printf("\tDCB state: %s\n", gw_dcb_state2string(dcb->state)); if (dcb->remote) printf("\tConnected to: %s\n", dcb->remote); if (dcb->user) printf("\tUsername to: %s\n", dcb->user); if (dcb->writeq) printf("\tQueued write data: %d\n",gwbuf_length(dcb->writeq)); printf("\tStatistics:\n"); printf("\t\tNo. of Reads: %d\n", dcb->stats.n_reads); printf("\t\tNo. of Writes: %d\n", dcb->stats.n_writes); printf("\t\tNo. of Buffered Writes: %d\n", dcb->stats.n_buffered); printf("\t\tNo. of Accepts: %d\n", dcb->stats.n_accepts); printf("\t\tNo. of High Water Events: %d\n", dcb->stats.n_high_water); printf("\t\tNo. of Low Water Events: %d\n", dcb->stats.n_low_water); } /** * Display an entry from the spinlock statistics data * * @param dcb The DCB to print to * @param desc Description of the statistic * @param value The statistic value */ static void spin_reporter(void *dcb, char *desc, int value) { dcb_printf((DCB *)dcb, "\t\t%-40s %d\n", desc, value); } /** * Diagnostic to print all DCB allocated in the system * */ void printAllDCBs() { DCB *dcb; spinlock_acquire(&dcbspin); dcb = allDCBs; while (dcb) { printDCB(dcb); dcb = dcb->next; } spinlock_release(&dcbspin); } /** * Diagnostic to print all DCB allocated in the system * */ void dprintAllDCBs(DCB *pdcb) { DCB *dcb; spinlock_acquire(&dcbspin); #if SPINLOCK_PROFILE dcb_printf(pdcb, "DCB List Spinlock Statistics:\n"); spinlock_stats(&dcbspin, spin_reporter, pdcb); dcb_printf(pdcb, "Zombie Queue Lock Statistics:\n"); spinlock_stats(&zombiespin, spin_reporter, pdcb); #endif dcb = allDCBs; while (dcb) { dcb_printf(pdcb, "DCB: %p\n", (void *)dcb); dcb_printf(pdcb, "\tDCB state: %s\n", gw_dcb_state2string(dcb->state)); if (dcb->session && dcb->session->service) dcb_printf(pdcb, "\tService: %s\n", dcb->session->service->name); if (dcb->remote) dcb_printf(pdcb, "\tConnected to: %s\n", dcb->remote); if (dcb->user) dcb_printf(pdcb, "\tUsername: %s\n", dcb->user); if (dcb->writeq) dcb_printf(pdcb, "\tQueued write data: %d\n", gwbuf_length(dcb->writeq)); dcb_printf(pdcb, "\tStatistics:\n"); dcb_printf(pdcb, "\t\tNo. of Reads: %d\n", dcb->stats.n_reads); dcb_printf(pdcb, "\t\tNo. of Writes: %d\n", dcb->stats.n_writes); dcb_printf(pdcb, "\t\tNo. of Buffered Writes: %d\n", dcb->stats.n_buffered); dcb_printf(pdcb, "\t\tNo. of Accepts: %d\n", dcb->stats.n_accepts); dcb_printf(pdcb, "\t\tNo. of High Water Events: %d\n", dcb->stats.n_high_water); dcb_printf(pdcb, "\t\tNo. of Low Water Events: %d\n", dcb->stats.n_low_water); if (dcb->flags & DCBF_CLONE) dcb_printf(pdcb, "\t\tDCB is a clone.\n"); dcb = dcb->next; } spinlock_release(&dcbspin); } /** * Diagnotic routine to print DCB data in a tabular form. * * @param pdcb DCB to print results to */ void dListDCBs(DCB *pdcb) { DCB *dcb; spinlock_acquire(&dcbspin); dcb = allDCBs; dcb_printf(pdcb, "Descriptor Control Blocks\n"); dcb_printf(pdcb, "------------------+----------------------------+--------------------+----------\n"); dcb_printf(pdcb, " %-16s | %-26s | %-18s | %s\n", "DCB", "State", "Service", "Remote"); dcb_printf(pdcb, "------------------+----------------------------+--------------------+----------\n"); while (dcb) { dcb_printf(pdcb, " %-16p | %-26s | %-18s | %s\n", dcb, gw_dcb_state2string(dcb->state), ((dcb->session && dcb->session->service) ? dcb->session->service->name : ""), (dcb->remote ? dcb->remote : "")); dcb = dcb->next; } dcb_printf(pdcb, "------------------+----------------------------+--------------------+----------\n\n"); spinlock_release(&dcbspin); } /** * Diagnotic routine to print client DCB data in a tabular form. * * @param pdcb DCB to print results to */ void dListClients(DCB *pdcb) { DCB *dcb; spinlock_acquire(&dcbspin); dcb = allDCBs; dcb_printf(pdcb, "Client Connections\n"); dcb_printf(pdcb, "-----------------+------------------+----------------------+------------\n"); dcb_printf(pdcb, " %-15s | %-16s | %-20s | %s\n", "Client", "DCB", "Service", "Session"); dcb_printf(pdcb, "-----------------+------------------+----------------------+------------\n"); while (dcb) { if (dcb_isclient(dcb) && dcb->dcb_role == DCB_ROLE_REQUEST_HANDLER) { dcb_printf(pdcb, " %-15s | %16p | %-20s | %10p\n", (dcb->remote ? dcb->remote : ""), dcb, (dcb->session->service ? dcb->session->service->name : ""), dcb->session); } dcb = dcb->next; } dcb_printf(pdcb, "-----------------+------------------+----------------------+------------\n\n"); spinlock_release(&dcbspin); } /** * Diagnostic to print a DCB to another DCB * * @param pdcb The DCB to which send the output * @param dcb The DCB to print */ void dprintDCB(DCB *pdcb, DCB *dcb) { dcb_printf(pdcb, "DCB: %p\n", (void *)dcb); dcb_printf(pdcb, "\tDCB state: %s\n", gw_dcb_state2string(dcb->state)); if (dcb->session && dcb->session->service) dcb_printf(pdcb, "\tService: %s\n", dcb->session->service->name); if (dcb->remote) dcb_printf(pdcb, "\tConnected to: %s\n", dcb->remote); if (dcb->user) dcb_printf(pdcb, "\tUsername: %s\n", dcb->user); dcb_printf(pdcb, "\tOwning Session: %p\n", dcb->session); if (dcb->writeq) dcb_printf(pdcb, "\tQueued write data: %d\n", gwbuf_length(dcb->writeq)); if (dcb->delayq) dcb_printf(pdcb, "\tDelayed write data: %d\n", gwbuf_length(dcb->delayq)); dcb_printf(pdcb, "\tStatistics:\n"); dcb_printf(pdcb, "\t\tNo. of Reads: %d\n", dcb->stats.n_reads); dcb_printf(pdcb, "\t\tNo. of Writes: %d\n", dcb->stats.n_writes); dcb_printf(pdcb, "\t\tNo. of Buffered Writes: %d\n", dcb->stats.n_buffered); dcb_printf(pdcb, "\t\tNo. of Accepts: %d\n", dcb->stats.n_accepts); dcb_printf(pdcb, "\t\tNo. of High Water Events: %d\n", dcb->stats.n_high_water); dcb_printf(pdcb, "\t\tNo. of Low Water Events: %d\n", dcb->stats.n_low_water); if (DCB_POLL_BUSY(dcb)) { dcb_printf(pdcb, "\t\tPending events in the queue: %x %s\n", dcb->evq.pending_events, dcb->evq.processing ? "(processing)" : ""); } if (dcb->flags & DCBF_CLONE) dcb_printf(pdcb, "\t\tDCB is a clone.\n"); #if SPINLOCK_PROFILE dcb_printf(pdcb, "\tInitlock Statistics:\n"); spinlock_stats(&dcb->dcb_initlock, spin_reporter, pdcb); dcb_printf(pdcb, "\tWrite Queue Lock Statistics:\n"); spinlock_stats(&dcb->writeqlock, spin_reporter, pdcb); dcb_printf(pdcb, "\tDelay Queue Lock Statistics:\n"); spinlock_stats(&dcb->delayqlock, spin_reporter, pdcb); dcb_printf(pdcb, "\tPollin Lock Statistics:\n"); spinlock_stats(&dcb->pollinlock, spin_reporter, pdcb); dcb_printf(pdcb, "\tPollout Lock Statistics:\n"); spinlock_stats(&dcb->polloutlock, spin_reporter, pdcb); dcb_printf(pdcb, "\tCallback Lock Statistics:\n"); spinlock_stats(&dcb->cb_lock, spin_reporter, pdcb); #endif } /** * Return a string representation of a DCB state. * * @param state The DCB state * @return String representation of the state * */ const char * gw_dcb_state2string (int state) { switch(state) { case DCB_STATE_ALLOC: return "DCB Allocated"; case DCB_STATE_POLLING: return "DCB in the polling loop"; case DCB_STATE_LISTENING: return "DCB for listening socket"; case DCB_STATE_DISCONNECTED: return "DCB socket closed"; case DCB_STATE_FREED: return "DCB memory could be freed"; case DCB_STATE_ZOMBIE: return "DCB Zombie"; default: return "DCB (unknown)"; } } /** * A DCB based wrapper for printf. Allows formatting printing to * a descritor control block. * * @param dcb Descriptor to write to * @param fmt A printf format string * @param ... Variable arguments for the print format */ void dcb_printf(DCB *dcb, const char *fmt, ...) { GWBUF *buf; va_list args; if ((buf = gwbuf_alloc(10240)) == NULL) return; va_start(args, fmt); vsnprintf(GWBUF_DATA(buf), 10240, fmt, args); va_end(args); buf->end = GWBUF_DATA(buf) + strlen(GWBUF_DATA(buf)); dcb->func.write(dcb, buf); } /** * Determine the role that a DCB plays within a session. * * @param dcb * @return Non-zero if the DCB is the client of the session */ int dcb_isclient(DCB *dcb) { if (dcb->state != DCB_STATE_LISTENING && dcb->session) { if (dcb->session->client) { return (dcb->session && dcb == dcb->session->client); } } return 0; } /** * Print hash table statistics to a DCB * * @param dcb The DCB to send the information to * @param table The hash table */ void dcb_hashtable_stats( DCB* dcb, void* table) { int total; int longest; int hashsize; total = 0; longest = 0; hashtable_get_stats(table, &hashsize, &total, &longest); dcb_printf(dcb, "Hashtable: %p, size %d\n", table, hashsize); dcb_printf(dcb, "\tNo. of entries: %d\n", total); dcb_printf(dcb, "\tAverage chain length: %.1f\n", (hashsize == 0 ? (float)hashsize : (float)total / hashsize)); dcb_printf(dcb, "\tLongest chain length: %d\n", longest); } bool dcb_set_state( DCB* dcb, const dcb_state_t new_state, dcb_state_t* old_state) { bool succp; dcb_state_t state ; CHK_DCB(dcb); spinlock_acquire(&dcb->dcb_initlock); succp = dcb_set_state_nomutex(dcb, new_state, &state); spinlock_release(&dcb->dcb_initlock); if (old_state != NULL) { *old_state = state; } return succp; } static bool dcb_set_state_nomutex( DCB* dcb, const dcb_state_t new_state, dcb_state_t* old_state) { bool succp = false; dcb_state_t state = DCB_STATE_UNDEFINED; CHK_DCB(dcb); state = dcb->state; if (old_state != NULL) { *old_state = state; } switch (state) { case DCB_STATE_UNDEFINED: dcb->state = new_state; succp = true; break; case DCB_STATE_ALLOC: switch (new_state) { /** fall through, for client requests */ case DCB_STATE_POLLING: /** fall through, for connect listeners */ case DCB_STATE_LISTENING: /** for failed connections */ case DCB_STATE_DISCONNECTED: dcb->state = new_state; succp = true; break; default: ss_dassert(old_state != NULL); break; } break; case DCB_STATE_POLLING: switch(new_state) { case DCB_STATE_NOPOLLING: dcb->state = new_state; succp = true; break; default: ss_dassert(old_state != NULL); break; } break; case DCB_STATE_LISTENING: switch(new_state) { case DCB_STATE_NOPOLLING: dcb->state = new_state; succp = true; break; default: ss_dassert(old_state != NULL); break; } break; case DCB_STATE_NOPOLLING: switch (new_state) { case DCB_STATE_ZOMBIE: /*< fall through */ dcb->state = new_state; case DCB_STATE_POLLING: /*< ok to try but state can't change */ succp = true; break; default: ss_dassert(old_state != NULL); break; } break; case DCB_STATE_ZOMBIE: switch (new_state) { case DCB_STATE_DISCONNECTED: /*< fall through */ dcb->state = new_state; case DCB_STATE_POLLING: /*< ok to try but state can't change */ succp = true; break; default: ss_dassert(old_state != NULL); break; } break; case DCB_STATE_DISCONNECTED: switch (new_state) { case DCB_STATE_FREED: dcb->state = new_state; succp = true; break; default: ss_dassert(old_state != NULL); break; } break; case DCB_STATE_FREED: ss_dassert(old_state != NULL); break; default: LOGIF(LE, (skygw_log_write_flush( LOGFILE_ERROR, "Error : Unknown dcb state %s for " "dcb %p", STRDCBSTATE(dcb->state), dcb))); ss_dassert(false); break; } /*< switch (dcb->state) */ if (succp) { LOGIF(LD, (skygw_log_write_flush( LOGFILE_DEBUG, "%lu [dcb_set_state_nomutex] dcb %p fd %d %s -> %s", pthread_self(), dcb, dcb->fd, STRDCBSTATE(state), STRDCBSTATE(dcb->state)))); } else { LOGIF(LD, (skygw_log_write( LOGFILE_DEBUG, "%lu [dcb_set_state_nomutex] Failed " "to change state of DCB %p. " "Old state %s > new state %s.", pthread_self(), dcb, (old_state == NULL ? "NULL" : STRDCBSTATE(*old_state)), STRDCBSTATE(new_state)))); } return succp; } /** * Write data to a DCB * * @param dcb The DCB to write buffer * @param buf Buffer to write * @param nbytes Number of bytes to write * @return Number of written bytes */ int gw_write(DCB *dcb, const void *buf, size_t nbytes) { int w = 0; int fd = dcb->fd; #if defined(FAKE_CODE) if (fd > 0 && dcb_fake_write_errno[fd] != 0) { ss_dassert(dcb_fake_write_ev[fd] != 0); w = write(fd, buf, nbytes/2); /*< leave peer to read missing bytes */ if (w > 0) { w = -1; errno = dcb_fake_write_errno[fd]; } } else if (fd > 0) { w = write(fd, buf, nbytes); } #else if (fd > 0) { w = write(fd, buf, nbytes); } #endif /* FAKE_CODE */ #if defined(SS_DEBUG_MYSQL) { size_t len; uint8_t* packet = (uint8_t *)buf; char* str; /** Print only MySQL packets */ if (w > 5) { str = (char *)&packet[5]; len = packet[0]; len += 256*packet[1]; len += 256*256*packet[2]; if (strncmp(str, "insert", 6) == 0 || strncmp(str, "create", 6) == 0 || strncmp(str, "drop", 4) == 0) { ss_dassert((dcb->dcb_server_status & (SERVER_RUNNING|SERVER_MASTER|SERVER_SLAVE))==(SERVER_RUNNING|SERVER_MASTER)); } if (strncmp(str, "set autocommit", 14) == 0 && nbytes > 17) { char* s = (char *)calloc(1, nbytes+1); if (nbytes-5 > len) { size_t len2 = packet[4+len]; len2 += 256*packet[4+len+1]; len2 += 256*256*packet[4+len+2]; char* str2 = (char *)&packet[4+len+5]; snprintf(s, 5+len+len2, "long %s %s", (char *)str, (char *)str2); } else { snprintf(s, len, "%s", (char *)str); } LOGIF(LT, (skygw_log_write( LOGFILE_TRACE, "%lu [gw_write] Wrote %d bytes : %s ", pthread_self(), w, s))); free(s); } } } #endif return w; } /** * Add a callback * * Duplicate registrations are not allowed, therefore an error will be * returned if the specific function, reason and userdata triple * are already registered. * An error will also be returned if the is insufficient memeory available to * create the registration. * * @param dcb The DCB to add the callback to * @param reason The callback reason * @param callback The callback function to call * @param userdata User data to send in the call * @return Non-zero (true) if the callback was added */ int dcb_add_callback(DCB *dcb, DCB_REASON reason, int (*callback)(struct dcb *, DCB_REASON, void *), void *userdata) { DCB_CALLBACK *cb, *ptr; int rval = 1; if ((ptr = (DCB_CALLBACK *)malloc(sizeof(DCB_CALLBACK))) == NULL) { return 0; } ptr->reason = reason; ptr->cb = callback; ptr->userdata = userdata; ptr->next = NULL; spinlock_acquire(&dcb->cb_lock); cb = dcb->callbacks; if (cb == NULL) { dcb->callbacks = ptr; spinlock_release(&dcb->cb_lock); } else { while (cb) { if (cb->reason == reason && cb->cb == callback && cb->userdata == userdata) { free(ptr); spinlock_release(&dcb->cb_lock); return 0; } if (cb->next == NULL) { cb->next = ptr; break; } cb = cb->next; } spinlock_release(&dcb->cb_lock); } return rval; } /** * Remove a callback from the callback list for the DCB * * Searches down the linked list to find the callback with a matching reason, function * and userdata. * * @param dcb The DCB to add the callback to * @param reason The callback reason * @param callback The callback function to call * @param userdata User data to send in the call * @return Non-zero (true) if the callback was removed */ int dcb_remove_callback(DCB *dcb, DCB_REASON reason, int (*callback)(struct dcb *, DCB_REASON, void *), void *userdata) { DCB_CALLBACK *cb, *pcb = NULL; int rval = 0; spinlock_acquire(&dcb->cb_lock); cb = dcb->callbacks; if (cb == NULL) { rval = 0; } else { while (cb) { if (cb->reason == reason && cb->cb == callback && cb->userdata == userdata) { if (pcb != NULL) pcb->next = cb->next; else dcb->callbacks = cb->next; spinlock_release(&dcb->cb_lock); free(cb); rval = 1; break; } pcb = cb; cb = cb->next; } } if (!rval) spinlock_release(&dcb->cb_lock); return rval; } /** * Call the set of callbacks registered for a particular reason. * * @param dcb The DCB to call the callbacks regarding * @param reason The reason that has triggered the call */ static void dcb_call_callback(DCB *dcb, DCB_REASON reason) { DCB_CALLBACK *cb, *nextcb; spinlock_acquire(&dcb->cb_lock); cb = dcb->callbacks; while (cb) { if (cb->reason == reason) { nextcb = cb->next; spinlock_release(&dcb->cb_lock); LOGIF(LD, (skygw_log_write(LOGFILE_DEBUG, "%lu [dcb_call_callback] %s", pthread_self(), STRDCBREASON(reason)))); cb->cb(dcb, reason, cb->userdata); spinlock_acquire(&dcb->cb_lock); cb = nextcb; } else cb = cb->next; } spinlock_release(&dcb->cb_lock); } /** * Check the passed DCB to ensure it is in the list of allDCBS * * @param dcb The DCB to check * @return 1 if the DCB is in the list, otherwise 0 */ int dcb_isvalid(DCB *dcb) { int rval = 0; if (dcb) { spinlock_acquire(&dcbspin); rval = dcb_isvalid_nolock(dcb); spinlock_release(&dcbspin); } return rval; } /** * Check the passed DCB to ensure it is in the list of allDCBS. * Requires that the DCB list is already locked before call. * * @param dcb The DCB to check * @return 1 if the DCB is in the list, otherwise 0 */ static int dcb_isvalid_nolock(DCB *dcb) { DCB *ptr; int rval = 0; if (dcb) { ptr = allDCBs; while (ptr && ptr != dcb) { ptr = ptr->next; } rval = (ptr == dcb); } return rval; } /** * Get the next DCB in the list of all DCB's * * @param dcb The current DCB * @return The pointer to the next DCB or NULL if this is the last */ static DCB * dcb_get_next (DCB* dcb) { spinlock_acquire(&dcbspin); if (dcb) { dcb = dcb_isvalid_nolock(dcb) ? dcb->next : NULL; } else dcb = allDCBs; spinlock_release(&dcbspin); return dcb; } /** * Call all the callbacks on all DCB's that match the server and the reason given * * @param reason The DCB_REASON that triggers the callback */ void dcb_call_foreach(struct server* server, DCB_REASON reason) { LOGIF(LD, (skygw_log_write(LOGFILE_DEBUG, "%lu [dcb_call_foreach]", pthread_self()))); switch (reason) { case DCB_REASON_CLOSE: case DCB_REASON_DRAINED: case DCB_REASON_HIGH_WATER: case DCB_REASON_LOW_WATER: case DCB_REASON_ERROR: case DCB_REASON_HUP: case DCB_REASON_NOT_RESPONDING: { DCB* dcb; dcb = dcb_get_next(NULL); while (dcb != NULL) { if (dcb->state == DCB_STATE_POLLING && dcb->server && strcmp(dcb->server->unique_name,server->unique_name) == 0) { dcb_call_callback(dcb, DCB_REASON_NOT_RESPONDING); } dcb = dcb_get_next(dcb); } break; } default: break; } return; } /** * Null protocol write routine used for cloned dcb's. It merely consumes * buffers written on the cloned DCB and sets the DCB_REPLIED flag. * * @param dcb The descriptor control block * @param buf The buffer being written * @return Always returns a good write operation result */ static int dcb_null_write(DCB *dcb, GWBUF *buf) { while (buf) { buf = gwbuf_consume(buf, GWBUF_LENGTH(buf)); } dcb->flags |= DCBF_REPLIED; return 1; } /** * Null protocol close operation for use by cloned DCB's. * * @param dcb The DCB being closed. */ static int dcb_null_close(DCB *dcb) { return 0; } /** * Null protocol auth operation for use by cloned DCB's. * * @param dcb The DCB being closed. * @param server The server to auth against * @param session The user session * @param buf The buffer with the new auth request */ static int dcb_null_auth(DCB *dcb, SERVER *server, SESSION *session, GWBUF *buf) { return 0; } /** * Return DCB counts optionally filtered by usage * * @param usage The usage of the DCB * @return A count of DCBs in the desired state */ int dcb_count_by_usage(DCB_USAGE usage) { int rval = 0; DCB *ptr; spinlock_acquire(&dcbspin); ptr = allDCBs; while (ptr) { switch (usage) { case DCB_USAGE_CLIENT: if (dcb_isclient(ptr)) rval++; break; case DCB_USAGE_LISTENER: if (ptr->state == DCB_STATE_LISTENING) rval++; break; case DCB_USAGE_BACKEND: if (dcb_isclient(ptr) == 0 && ptr->dcb_role == DCB_ROLE_REQUEST_HANDLER) rval++; break; case DCB_USAGE_INTERNAL: if (ptr->dcb_role == DCB_ROLE_REQUEST_HANDLER) rval++; break; case DCB_USAGE_ZOMBIE: if (DCB_ISZOMBIE(ptr)) rval++; break; case DCB_USAGE_ALL: rval++; break; } ptr = ptr->next; } spinlock_release(&dcbspin); return rval; }