aa517205b7
First attempt to split MySQL routines in client and backend libraries. Compiled on Centos but not tested mysql_protocol.h header file is coming soon.
268 lines
7.3 KiB
C
268 lines
7.3 KiB
C
/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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#include "mysql_protocol.h"
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/*
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* MySQL Protocol module for handling the protocol between the gateway
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* and the backend MySQL database.
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*
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* Revision History
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* Date Who Description
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* 14/06/2013 Mark Riddoch Initial version
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* 17/06/2013 Massimiliano Pinto Added Gateway To Backends routines
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*/
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static char *version_str = "V1.0.0";
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static int gw_read_backend_event(DCB* dcb, int epfd);
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static int gw_write_backend_event(DCB *dcb, int epfd);
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static int gw_MySQLWrite_backend(DCB *dcb, GWBUF *queue);
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static int gw_error_backend_event(DCB *dcb, int epfd, int event);
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static GWPROTOCOL MyObject = {
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gw_read_backend_event, /* Read - EPOLLIN handler */
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gw_MySQLWrite_backend, /* Write - data from gateway */
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gw_write_backend_event, /* WriteReady - EPOLLOUT handler */
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gw_error_backend_event, /* Error - EPOLLERR handler */
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NULL, /* HangUp - EPOLLHUP handler */
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NULL, /* Accept */
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NULL, /* Connect */
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NULL /* Close */
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};
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/*
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* Implementation of the mandatory version entry point
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*
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* @return version string of the module
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*/
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char *
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version()
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{
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return version_str;
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}
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/*
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* The module initialisation routine, called when the module
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* is first loaded.
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*/
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void
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ModuleInit()
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{
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fprintf(stderr, "Initial MySQL Client Protcol module.\n");
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}
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/*
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* The module entry point routine. It is this routine that
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* must populate the structure that is referred to as the
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* "module object", this is a structure with the set of
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* external entry points for this module.
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*
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* @return The module object
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*/
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GWPROTOCOL *
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GetModuleObject()
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{
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return &MyObject;
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}
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//////////////////////////////////////////
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//backend read event triggered by EPOLLIN
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//////////////////////////////////////////
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int gw_read_backend_event(DCB *dcb, int epfd) {
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int n;
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MySQLProtocol *client_protocol = NULL;
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if (dcb)
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if(dcb->session)
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client_protocol = SESSION_PROTOCOL(dcb->session, MySQLProtocol);
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#ifdef GW_DEBUG_READ_EVENT
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fprintf(stderr, "Backend ready! Read from Backend %i, write to client %i, client state %i\n", dcb->fd, dcb->session->client->fd, client_protocol->state);
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#endif
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if ((client_protocol->state == MYSQL_WAITING_RESULT) || (client_protocol->state == MYSQL_IDLE)) {
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struct epoll_event new_event;
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int w;
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int b = -1;
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int tot_b = -1;
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uint8_t *ptr_buffer;
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GWBUF *buffer, *head;
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if (ioctl(dcb->fd, FIONREAD, &b)) {
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fprintf(stderr, "Backend Ioctl FIONREAD error %i, %s\n", errno , strerror(errno));
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} else {
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//fprintf(stderr, "Backend IOCTL FIONREAD bytes to read = %i\n", b);
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}
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/*
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* Read all the data that is available into a chain of buffers
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*/
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head = NULL;
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while (b > 0)
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{
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int bufsize = b < MAX_BUFFER_SIZE ? b : MAX_BUFFER_SIZE;
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if ((buffer = gwbuf_alloc(bufsize)) == NULL)
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{
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/* Bad news, we have run out of memory */
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return 0;
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}
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GW_NOINTR_CALL(n = read(dcb->fd, GWBUF_DATA(buffer), bufsize); dcb->stats.n_reads++);
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if (n < 0)
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{
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// if eerno == EAGAIN || EWOULDBLOCK is missing
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// do the right task, not just break
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break;
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}
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head = gwbuf_append(head, buffer);
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// how many bytes left
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b -= n;
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}
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// write the gwbuffer to client
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dcb->session->client->func.write(dcb->session->client, head);
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return 1;
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}
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return 1;
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}
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//////////////////////////////////////////
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//backend write event triggered by EPOLLOUT
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//////////////////////////////////////////
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int gw_write_backend_event(DCB *dcb, int epfd) {
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//fprintf(stderr, ">>> gw_write_backend_event for %i\n", dcb->fd);
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return 0;
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}
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/*
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* Write function for client DCB
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*
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* @param dcb The DCB of the client
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* @param queue Queue of buffers to write
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*/
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int
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gw_MySQLWrite_backend(DCB *dcb, GWBUF *queue)
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{
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int w, saved_errno = 0;
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spinlock_acquire(&dcb->writeqlock);
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if (dcb->writeq)
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{
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/*
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* We have some queued data, so add our data to
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* the write queue and return.
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* The assumption is that there will be an EPOLLOUT
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* event to drain what is already queued. We are protected
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* by the spinlock, which will also be acquired by the
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* the routine that drains the queue data, so we should
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* not have a race condition on the event.
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*/
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dcb->writeq = gwbuf_append(dcb->writeq, queue);
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dcb->stats.n_buffered++;
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}
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else
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{
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int len;
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/*
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* Loop over the buffer chain that has been passed to us
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* from the reading side.
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* Send as much of the data in that chain as possible and
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* add any balance to the write queue.
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*/
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while (queue != NULL)
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{
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len = GWBUF_LENGTH(queue);
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GW_NOINTR_CALL(w = write(dcb->fd, GWBUF_DATA(queue), len); dcb->stats.n_writes++);
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saved_errno = errno;
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if (w < 0)
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{
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break;
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}
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/*
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* Pull the number of bytes we have written from
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* queue with have.
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*/
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queue = gwbuf_consume(queue, w);
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if (w < len)
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{
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/* We didn't write all the data */
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}
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}
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/* Buffer the balance of any data */
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dcb->writeq = queue;
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if (queue)
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{
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dcb->stats.n_buffered++;
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}
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}
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spinlock_release(&dcb->writeqlock);
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if (queue && (saved_errno != EAGAIN || saved_errno != EWOULDBLOCK))
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{
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/* We had a real write failure that we must deal with */
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return 0;
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}
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return 1;
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}
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int gw_error_backend_event(DCB *dcb, int epfd, int event) {
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struct epoll_event ed;
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MySQLProtocol *protocol = DCB_PROTOCOL(dcb, MySQLProtocol);
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fprintf(stderr, "#### Handle Backend error function for %i\n", dcb->fd);
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#ifdef GW_EVENT_DEBUG
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if (event != -1) {
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fprintf(stderr, ">>>>>> Backend DCB state %i, Protocol State %i: event %i, %i\n", dcb->state, dcb->proto_state, event & EPOLLERR, event & EPOLLHUP);
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if(event & EPOLLHUP)
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fprintf(stderr, "EPOLLHUP\n");
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if(event & EPOLLERR)
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fprintf(stderr, "EPOLLERR\n");
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if(event & EPOLLPRI)
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fprintf(stderr, "EPOLLPRI\n");
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}
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#endif
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if (dcb->state != DCB_STATE_LISTENING) {
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if (epoll_ctl(epfd, EPOLL_CTL_DEL, dcb->fd, &ed) == -1) {
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fprintf(stderr, "Backend epoll_ctl_del: from events check failed to delete %i, [%i]:[%s]\n", dcb->fd, errno, strerror(errno));
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}
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#ifdef GW_EVENT_DEBUG
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fprintf(stderr, "Backend closing fd [%i]=%i, from events check\n", dcb->fd, protocol->fd);
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#endif
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if (dcb->fd) {
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dcb->state = DCB_STATE_DISCONNECTED;
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fprintf(stderr, "Freeing backend MySQL conn %p, %p\n", dcb->protocol, &dcb->protocol);
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gw_mysql_close((MySQLProtocol **)&dcb->protocol);
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fprintf(stderr, "Freeing backend MySQL conn %p, %p\n", dcb->protocol, &dcb->protocol);
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}
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}
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}
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