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/* Copyright (c) 2009-2020, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "server.h"
#include "cluster.h"
#include <math.h>
/* ========================== Clients timeouts ============================= */
/* Check if this blocked client timedout (does nothing if the client is
* not blocked right now). If so send a reply, unblock it, and return 1.
* Otherwise 0 is returned and no operation is performed. */
int checkBlockedClientTimeout(client *c, mstime_t now) {
if (c->flags & CLIENT_BLOCKED &&
c->bstate.timeout != 0
&& c->bstate.timeout < now)
{
/* Handle blocking operation specific timeout. */
unblockClientOnTimeout(c);
return 1;
} else {
return 0;
}
}
/* Check for timeouts. Returns non-zero if the client was terminated.
* The function gets the current time in milliseconds as argument since
* it gets called multiple times in a loop, so calling gettimeofday() for
* each iteration would be costly without any actual gain. */
int clientsCronHandleTimeout(client *c, mstime_t now_ms) {
time_t now = now_ms/1000;
if (server.maxidletime &&
/* This handles the idle clients connection timeout if set. */
!(c->flags & CLIENT_SLAVE) && /* No timeout for slaves and monitors */
!mustObeyClient(c) && /* No timeout for masters and AOF */
!(c->flags & CLIENT_BLOCKED) && /* No timeout for BLPOP */
!(c->flags & CLIENT_PUBSUB) && /* No timeout for Pub/Sub clients */
(now - c->lastinteraction > server.maxidletime))
{
serverLog(LL_VERBOSE,"Closing idle client");
freeClient(c);
return 1;
} else if (c->flags & CLIENT_BLOCKED) {
/* Cluster: handle unblock & redirect of clients blocked
* into keys no longer served by this server. */
if (server.cluster_enabled) {
if (clusterRedirectBlockedClientIfNeeded(c))
unblockClientOnError(c, NULL);
}
}
return 0;
}
/* For blocked clients timeouts we populate a radix tree of 128 bit keys
* composed as such:
*
* [8 byte big endian expire time]+[8 byte client ID]
*
* We don't do any cleanup in the Radix tree: when we run the clients that
* reached the timeout already, if they are no longer existing or no longer
* blocked with such timeout, we just go forward.
*
* Every time a client blocks with a timeout, we add the client in
* the tree. In beforeSleep() we call handleBlockedClientsTimeout() to run
* the tree and unblock the clients. */
#define CLIENT_ST_KEYLEN 16 /* 8 bytes mstime + 8 bytes client ID. */
/* Given client ID and timeout, write the resulting radix tree key in buf. */
void encodeTimeoutKey(unsigned char *buf, uint64_t timeout, client *c) {
timeout = htonu64(timeout);
memcpy(buf,&timeout,sizeof(timeout));
memcpy(buf+8,&c,sizeof(c));
if (sizeof(c) == 4) memset(buf+12,0,4); /* Zero padding for 32bit target. */
}
/* Given a key encoded with encodeTimeoutKey(), resolve the fields and write
* the timeout into *toptr and the client pointer into *cptr. */
void decodeTimeoutKey(unsigned char *buf, uint64_t *toptr, client **cptr) {
memcpy(toptr,buf,sizeof(*toptr));
*toptr = ntohu64(*toptr);
memcpy(cptr,buf+8,sizeof(*cptr));
}
/* Add the specified client id / timeout as a key in the radix tree we use
* to handle blocked clients timeouts. The client is not added to the list
* if its timeout is zero (block forever). */
void addClientToTimeoutTable(client *c) {
if (c->bstate.timeout == 0) return;
uint64_t timeout = c->bstate.timeout;
unsigned char buf[CLIENT_ST_KEYLEN];
encodeTimeoutKey(buf,timeout,c);
if (raxTryInsert(server.clients_timeout_table,buf,sizeof(buf),NULL,NULL))
c->flags |= CLIENT_IN_TO_TABLE;
}
/* Remove the client from the table when it is unblocked for reasons
* different than timing out. */
void removeClientFromTimeoutTable(client *c) {
if (!(c->flags & CLIENT_IN_TO_TABLE)) return;
c->flags &= ~CLIENT_IN_TO_TABLE;
uint64_t timeout = c->bstate.timeout;
unsigned char buf[CLIENT_ST_KEYLEN];
encodeTimeoutKey(buf,timeout,c);
raxRemove(server.clients_timeout_table,buf,sizeof(buf),NULL);
}
/* This function is called in beforeSleep() in order to unblock clients
* that are waiting in blocking operations with a timeout set. */
void handleBlockedClientsTimeout(void) {
if (raxSize(server.clients_timeout_table) == 0) return;
uint64_t now = mstime();
raxIterator ri;
raxStart(&ri,server.clients_timeout_table);
raxSeek(&ri,"^",NULL,0);
while(raxNext(&ri)) {
uint64_t timeout;
client *c;
decodeTimeoutKey(ri.key,&timeout,&c);
if (timeout >= now) break; /* All the timeouts are in the future. */
c->flags &= ~CLIENT_IN_TO_TABLE;
checkBlockedClientTimeout(c,now);
raxRemove(server.clients_timeout_table,ri.key,ri.key_len,NULL);
raxSeek(&ri,"^",NULL,0);
}
raxStop(&ri);
}
/* Get a timeout value from an object and store it into 'timeout'.
* The final timeout is always stored as milliseconds as a time where the
* timeout will expire, however the parsing is performed according to
* the 'unit' that can be seconds or milliseconds.
*
* Note that if the timeout is zero (usually from the point of view of
* commands API this means no timeout) the value stored into 'timeout'
* is zero. */
int getTimeoutFromObjectOrReply(client *c, robj *object, mstime_t *timeout, int unit) {
long long tval;
long double ftval;
mstime_t now = commandTimeSnapshot();
if (unit == UNIT_SECONDS) {
if (getLongDoubleFromObjectOrReply(c,object,&ftval,
"timeout is not a float or out of range") != C_OK)
return C_ERR;
ftval *= 1000.0; /* seconds => millisec */
if (ftval > LLONG_MAX) {
addReplyError(c, "timeout is out of range");
return C_ERR;
}
tval = (long long) ceill(ftval);
} else {
if (getLongLongFromObjectOrReply(c,object,&tval,
"timeout is not an integer or out of range") != C_OK)
return C_ERR;
}
if (tval < 0) {
addReplyError(c,"timeout is negative");
return C_ERR;
}
if (tval > 0) {
if (tval > LLONG_MAX - now) {
addReplyError(c,"timeout is out of range"); /* 'tval+now' would overflow */
return C_ERR;
}
tval += now;
}
*timeout = tval;
return C_OK;
}
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