xref: /redis-3.2.3/src/networking.c (revision 28343966)
1 /*
2  * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *
8  *   * Redistributions of source code must retain the above copyright notice,
9  *     this list of conditions and the following disclaimer.
10  *   * Redistributions in binary form must reproduce the above copyright
11  *     notice, this list of conditions and the following disclaimer in the
12  *     documentation and/or other materials provided with the distribution.
13  *   * Neither the name of Redis nor the names of its contributors may be used
14  *     to endorse or promote products derived from this software without
15  *     specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include "redis.h"
31 #include <sys/uio.h>
32 #include <math.h>
33 
34 static void setProtocolError(redisClient *c, int pos);
35 
36 /* To evaluate the output buffer size of a client we need to get size of
37  * allocated objects, however we can't used zmalloc_size() directly on sds
38  * strings because of the trick they use to work (the header is before the
39  * returned pointer), so we use this helper function. */
40 size_t zmalloc_size_sds(sds s) {
41     return zmalloc_size(s-sizeof(struct sdshdr));
42 }
43 
44 /* Return the amount of memory used by the sds string at object->ptr
45  * for a string object. */
46 size_t getStringObjectSdsUsedMemory(robj *o) {
47     redisAssertWithInfo(NULL,o,o->type == REDIS_STRING);
48     switch(o->encoding) {
49     case REDIS_ENCODING_RAW: return zmalloc_size_sds(o->ptr);
50     case REDIS_ENCODING_EMBSTR: return sdslen(o->ptr);
51     default: return 0; /* Just integer encoding for now. */
52     }
53 }
54 
55 void *dupClientReplyValue(void *o) {
56     incrRefCount((robj*)o);
57     return o;
58 }
59 
60 int listMatchObjects(void *a, void *b) {
61     return equalStringObjects(a,b);
62 }
63 
64 redisClient *createClient(int fd) {
65     redisClient *c = zmalloc(sizeof(redisClient));
66 
67     /* passing -1 as fd it is possible to create a non connected client.
68      * This is useful since all the Redis commands needs to be executed
69      * in the context of a client. When commands are executed in other
70      * contexts (for instance a Lua script) we need a non connected client. */
71     if (fd != -1) {
72         anetNonBlock(NULL,fd);
73         anetEnableTcpNoDelay(NULL,fd);
74         if (server.tcpkeepalive)
75             anetKeepAlive(NULL,fd,server.tcpkeepalive);
76         if (aeCreateFileEvent(server.el,fd,AE_READABLE,
77             readQueryFromClient, c) == AE_ERR)
78         {
79             close(fd);
80             zfree(c);
81             return NULL;
82         }
83     }
84 
85     selectDb(c,0);
86     c->id = server.next_client_id++;
87     c->fd = fd;
88     c->name = NULL;
89     c->bufpos = 0;
90     c->querybuf = sdsempty();
91     c->querybuf_peak = 0;
92     c->reqtype = 0;
93     c->argc = 0;
94     c->argv = NULL;
95     c->cmd = c->lastcmd = NULL;
96     c->multibulklen = 0;
97     c->bulklen = -1;
98     c->sentlen = 0;
99     c->flags = 0;
100     c->ctime = c->lastinteraction = server.unixtime;
101     c->authenticated = 0;
102     c->replstate = REDIS_REPL_NONE;
103     c->reploff = 0;
104     c->repl_ack_off = 0;
105     c->repl_ack_time = 0;
106     c->slave_listening_port = 0;
107     c->reply = listCreate();
108     c->reply_bytes = 0;
109     c->obuf_soft_limit_reached_time = 0;
110     listSetFreeMethod(c->reply,decrRefCountVoid);
111     listSetDupMethod(c->reply,dupClientReplyValue);
112     c->btype = REDIS_BLOCKED_NONE;
113     c->bpop.timeout = 0;
114     c->bpop.keys = dictCreate(&setDictType,NULL);
115     c->bpop.target = NULL;
116     c->bpop.numreplicas = 0;
117     c->bpop.reploffset = 0;
118     c->woff = 0;
119     c->watched_keys = listCreate();
120     c->pubsub_channels = dictCreate(&setDictType,NULL);
121     c->pubsub_patterns = listCreate();
122     c->peerid = NULL;
123     listSetFreeMethod(c->pubsub_patterns,decrRefCountVoid);
124     listSetMatchMethod(c->pubsub_patterns,listMatchObjects);
125     if (fd != -1) listAddNodeTail(server.clients,c);
126     initClientMultiState(c);
127     return c;
128 }
129 
130 /* This function is called every time we are going to transmit new data
131  * to the client. The behavior is the following:
132  *
133  * If the client should receive new data (normal clients will) the function
134  * returns REDIS_OK, and make sure to install the write handler in our event
135  * loop so that when the socket is writable new data gets written.
136  *
137  * If the client should not receive new data, because it is a fake client,
138  * a master, a slave not yet online, or because the setup of the write handler
139  * failed, the function returns REDIS_ERR.
140  *
141  * Typically gets called every time a reply is built, before adding more
142  * data to the clients output buffers. If the function returns REDIS_ERR no
143  * data should be appended to the output buffers. */
144 int prepareClientToWrite(redisClient *c) {
145     if (c->flags & REDIS_LUA_CLIENT) return REDIS_OK;
146     if ((c->flags & REDIS_MASTER) &&
147         !(c->flags & REDIS_MASTER_FORCE_REPLY)) return REDIS_ERR;
148     if (c->fd <= 0) return REDIS_ERR; /* Fake client */
149     if (c->bufpos == 0 && listLength(c->reply) == 0 &&
150         (c->replstate == REDIS_REPL_NONE ||
151          c->replstate == REDIS_REPL_ONLINE) &&
152         aeCreateFileEvent(server.el, c->fd, AE_WRITABLE,
153         sendReplyToClient, c) == AE_ERR) return REDIS_ERR;
154     return REDIS_OK;
155 }
156 
157 /* Create a duplicate of the last object in the reply list when
158  * it is not exclusively owned by the reply list. */
159 robj *dupLastObjectIfNeeded(list *reply) {
160     robj *new, *cur;
161     listNode *ln;
162     redisAssert(listLength(reply) > 0);
163     ln = listLast(reply);
164     cur = listNodeValue(ln);
165     if (cur->refcount > 1) {
166         new = dupStringObject(cur);
167         decrRefCount(cur);
168         listNodeValue(ln) = new;
169     }
170     return listNodeValue(ln);
171 }
172 
173 /* -----------------------------------------------------------------------------
174  * Low level functions to add more data to output buffers.
175  * -------------------------------------------------------------------------- */
176 
177 int _addReplyToBuffer(redisClient *c, char *s, size_t len) {
178     size_t available = sizeof(c->buf)-c->bufpos;
179 
180     if (c->flags & REDIS_CLOSE_AFTER_REPLY) return REDIS_OK;
181 
182     /* If there already are entries in the reply list, we cannot
183      * add anything more to the static buffer. */
184     if (listLength(c->reply) > 0) return REDIS_ERR;
185 
186     /* Check that the buffer has enough space available for this string. */
187     if (len > available) return REDIS_ERR;
188 
189     memcpy(c->buf+c->bufpos,s,len);
190     c->bufpos+=len;
191     return REDIS_OK;
192 }
193 
194 void _addReplyObjectToList(redisClient *c, robj *o) {
195     robj *tail;
196 
197     if (c->flags & REDIS_CLOSE_AFTER_REPLY) return;
198 
199     if (listLength(c->reply) == 0) {
200         incrRefCount(o);
201         listAddNodeTail(c->reply,o);
202         c->reply_bytes += getStringObjectSdsUsedMemory(o);
203     } else {
204         tail = listNodeValue(listLast(c->reply));
205 
206         /* Append to this object when possible. */
207         if (tail->ptr != NULL &&
208             tail->encoding == REDIS_ENCODING_RAW &&
209             sdslen(tail->ptr)+sdslen(o->ptr) <= REDIS_REPLY_CHUNK_BYTES)
210         {
211             c->reply_bytes -= zmalloc_size_sds(tail->ptr);
212             tail = dupLastObjectIfNeeded(c->reply);
213             tail->ptr = sdscatlen(tail->ptr,o->ptr,sdslen(o->ptr));
214             c->reply_bytes += zmalloc_size_sds(tail->ptr);
215         } else {
216             incrRefCount(o);
217             listAddNodeTail(c->reply,o);
218             c->reply_bytes += getStringObjectSdsUsedMemory(o);
219         }
220     }
221     asyncCloseClientOnOutputBufferLimitReached(c);
222 }
223 
224 /* This method takes responsibility over the sds. When it is no longer
225  * needed it will be free'd, otherwise it ends up in a robj. */
226 void _addReplySdsToList(redisClient *c, sds s) {
227     robj *tail;
228 
229     if (c->flags & REDIS_CLOSE_AFTER_REPLY) {
230         sdsfree(s);
231         return;
232     }
233 
234     if (listLength(c->reply) == 0) {
235         listAddNodeTail(c->reply,createObject(REDIS_STRING,s));
236         c->reply_bytes += zmalloc_size_sds(s);
237     } else {
238         tail = listNodeValue(listLast(c->reply));
239 
240         /* Append to this object when possible. */
241         if (tail->ptr != NULL && tail->encoding == REDIS_ENCODING_RAW &&
242             sdslen(tail->ptr)+sdslen(s) <= REDIS_REPLY_CHUNK_BYTES)
243         {
244             c->reply_bytes -= zmalloc_size_sds(tail->ptr);
245             tail = dupLastObjectIfNeeded(c->reply);
246             tail->ptr = sdscatlen(tail->ptr,s,sdslen(s));
247             c->reply_bytes += zmalloc_size_sds(tail->ptr);
248             sdsfree(s);
249         } else {
250             listAddNodeTail(c->reply,createObject(REDIS_STRING,s));
251             c->reply_bytes += zmalloc_size_sds(s);
252         }
253     }
254     asyncCloseClientOnOutputBufferLimitReached(c);
255 }
256 
257 void _addReplyStringToList(redisClient *c, char *s, size_t len) {
258     robj *tail;
259 
260     if (c->flags & REDIS_CLOSE_AFTER_REPLY) return;
261 
262     if (listLength(c->reply) == 0) {
263         robj *o = createStringObject(s,len);
264 
265         listAddNodeTail(c->reply,o);
266         c->reply_bytes += getStringObjectSdsUsedMemory(o);
267     } else {
268         tail = listNodeValue(listLast(c->reply));
269 
270         /* Append to this object when possible. */
271         if (tail->ptr != NULL && tail->encoding == REDIS_ENCODING_RAW &&
272             sdslen(tail->ptr)+len <= REDIS_REPLY_CHUNK_BYTES)
273         {
274             c->reply_bytes -= zmalloc_size_sds(tail->ptr);
275             tail = dupLastObjectIfNeeded(c->reply);
276             tail->ptr = sdscatlen(tail->ptr,s,len);
277             c->reply_bytes += zmalloc_size_sds(tail->ptr);
278         } else {
279             robj *o = createStringObject(s,len);
280 
281             listAddNodeTail(c->reply,o);
282             c->reply_bytes += getStringObjectSdsUsedMemory(o);
283         }
284     }
285     asyncCloseClientOnOutputBufferLimitReached(c);
286 }
287 
288 /* -----------------------------------------------------------------------------
289  * Higher level functions to queue data on the client output buffer.
290  * The following functions are the ones that commands implementations will call.
291  * -------------------------------------------------------------------------- */
292 
293 void addReply(redisClient *c, robj *obj) {
294     if (prepareClientToWrite(c) != REDIS_OK) return;
295 
296     /* This is an important place where we can avoid copy-on-write
297      * when there is a saving child running, avoiding touching the
298      * refcount field of the object if it's not needed.
299      *
300      * If the encoding is RAW and there is room in the static buffer
301      * we'll be able to send the object to the client without
302      * messing with its page. */
303     if (sdsEncodedObject(obj)) {
304         if (_addReplyToBuffer(c,obj->ptr,sdslen(obj->ptr)) != REDIS_OK)
305             _addReplyObjectToList(c,obj);
306     } else if (obj->encoding == REDIS_ENCODING_INT) {
307         /* Optimization: if there is room in the static buffer for 32 bytes
308          * (more than the max chars a 64 bit integer can take as string) we
309          * avoid decoding the object and go for the lower level approach. */
310         if (listLength(c->reply) == 0 && (sizeof(c->buf) - c->bufpos) >= 32) {
311             char buf[32];
312             int len;
313 
314             len = ll2string(buf,sizeof(buf),(long)obj->ptr);
315             if (_addReplyToBuffer(c,buf,len) == REDIS_OK)
316                 return;
317             /* else... continue with the normal code path, but should never
318              * happen actually since we verified there is room. */
319         }
320         obj = getDecodedObject(obj);
321         if (_addReplyToBuffer(c,obj->ptr,sdslen(obj->ptr)) != REDIS_OK)
322             _addReplyObjectToList(c,obj);
323         decrRefCount(obj);
324     } else {
325         redisPanic("Wrong obj->encoding in addReply()");
326     }
327 }
328 
329 void addReplySds(redisClient *c, sds s) {
330     if (prepareClientToWrite(c) != REDIS_OK) {
331         /* The caller expects the sds to be free'd. */
332         sdsfree(s);
333         return;
334     }
335     if (_addReplyToBuffer(c,s,sdslen(s)) == REDIS_OK) {
336         sdsfree(s);
337     } else {
338         /* This method free's the sds when it is no longer needed. */
339         _addReplySdsToList(c,s);
340     }
341 }
342 
343 void addReplyString(redisClient *c, char *s, size_t len) {
344     if (prepareClientToWrite(c) != REDIS_OK) return;
345     if (_addReplyToBuffer(c,s,len) != REDIS_OK)
346         _addReplyStringToList(c,s,len);
347 }
348 
349 void addReplyErrorLength(redisClient *c, char *s, size_t len) {
350     addReplyString(c,"-ERR ",5);
351     addReplyString(c,s,len);
352     addReplyString(c,"\r\n",2);
353 }
354 
355 void addReplyError(redisClient *c, char *err) {
356     addReplyErrorLength(c,err,strlen(err));
357 }
358 
359 void addReplyErrorFormat(redisClient *c, const char *fmt, ...) {
360     size_t l, j;
361     va_list ap;
362     va_start(ap,fmt);
363     sds s = sdscatvprintf(sdsempty(),fmt,ap);
364     va_end(ap);
365     /* Make sure there are no newlines in the string, otherwise invalid protocol
366      * is emitted. */
367     l = sdslen(s);
368     for (j = 0; j < l; j++) {
369         if (s[j] == '\r' || s[j] == '\n') s[j] = ' ';
370     }
371     addReplyErrorLength(c,s,sdslen(s));
372     sdsfree(s);
373 }
374 
375 void addReplyStatusLength(redisClient *c, char *s, size_t len) {
376     addReplyString(c,"+",1);
377     addReplyString(c,s,len);
378     addReplyString(c,"\r\n",2);
379 }
380 
381 void addReplyStatus(redisClient *c, char *status) {
382     addReplyStatusLength(c,status,strlen(status));
383 }
384 
385 void addReplyStatusFormat(redisClient *c, const char *fmt, ...) {
386     va_list ap;
387     va_start(ap,fmt);
388     sds s = sdscatvprintf(sdsempty(),fmt,ap);
389     va_end(ap);
390     addReplyStatusLength(c,s,sdslen(s));
391     sdsfree(s);
392 }
393 
394 /* Adds an empty object to the reply list that will contain the multi bulk
395  * length, which is not known when this function is called. */
396 void *addDeferredMultiBulkLength(redisClient *c) {
397     /* Note that we install the write event here even if the object is not
398      * ready to be sent, since we are sure that before returning to the
399      * event loop setDeferredMultiBulkLength() will be called. */
400     if (prepareClientToWrite(c) != REDIS_OK) return NULL;
401     listAddNodeTail(c->reply,createObject(REDIS_STRING,NULL));
402     return listLast(c->reply);
403 }
404 
405 /* Populate the length object and try gluing it to the next chunk. */
406 void setDeferredMultiBulkLength(redisClient *c, void *node, long length) {
407     listNode *ln = (listNode*)node;
408     robj *len, *next;
409 
410     /* Abort when *node is NULL (see addDeferredMultiBulkLength). */
411     if (node == NULL) return;
412 
413     len = listNodeValue(ln);
414     len->ptr = sdscatprintf(sdsempty(),"*%ld\r\n",length);
415     len->encoding = REDIS_ENCODING_RAW; /* in case it was an EMBSTR. */
416     c->reply_bytes += zmalloc_size_sds(len->ptr);
417     if (ln->next != NULL) {
418         next = listNodeValue(ln->next);
419 
420         /* Only glue when the next node is non-NULL (an sds in this case) */
421         if (next->ptr != NULL) {
422             c->reply_bytes -= zmalloc_size_sds(len->ptr);
423             c->reply_bytes -= getStringObjectSdsUsedMemory(next);
424             len->ptr = sdscatlen(len->ptr,next->ptr,sdslen(next->ptr));
425             c->reply_bytes += zmalloc_size_sds(len->ptr);
426             listDelNode(c->reply,ln->next);
427         }
428     }
429     asyncCloseClientOnOutputBufferLimitReached(c);
430 }
431 
432 /* Add a double as a bulk reply */
433 void addReplyDouble(redisClient *c, double d) {
434     char dbuf[128], sbuf[128];
435     int dlen, slen;
436     if (isinf(d)) {
437         /* Libc in odd systems (Hi Solaris!) will format infinite in a
438          * different way, so better to handle it in an explicit way. */
439         addReplyBulkCString(c, d > 0 ? "inf" : "-inf");
440     } else {
441         dlen = snprintf(dbuf,sizeof(dbuf),"%.17g",d);
442         slen = snprintf(sbuf,sizeof(sbuf),"$%d\r\n%s\r\n",dlen,dbuf);
443         addReplyString(c,sbuf,slen);
444     }
445 }
446 
447 /* Add a long long as integer reply or bulk len / multi bulk count.
448  * Basically this is used to output <prefix><long long><crlf>. */
449 void addReplyLongLongWithPrefix(redisClient *c, long long ll, char prefix) {
450     char buf[128];
451     int len;
452 
453     /* Things like $3\r\n or *2\r\n are emitted very often by the protocol
454      * so we have a few shared objects to use if the integer is small
455      * like it is most of the times. */
456     if (prefix == '*' && ll < REDIS_SHARED_BULKHDR_LEN) {
457         addReply(c,shared.mbulkhdr[ll]);
458         return;
459     } else if (prefix == '$' && ll < REDIS_SHARED_BULKHDR_LEN) {
460         addReply(c,shared.bulkhdr[ll]);
461         return;
462     }
463 
464     buf[0] = prefix;
465     len = ll2string(buf+1,sizeof(buf)-1,ll);
466     buf[len+1] = '\r';
467     buf[len+2] = '\n';
468     addReplyString(c,buf,len+3);
469 }
470 
471 void addReplyLongLong(redisClient *c, long long ll) {
472     if (ll == 0)
473         addReply(c,shared.czero);
474     else if (ll == 1)
475         addReply(c,shared.cone);
476     else
477         addReplyLongLongWithPrefix(c,ll,':');
478 }
479 
480 void addReplyMultiBulkLen(redisClient *c, long length) {
481     if (length < REDIS_SHARED_BULKHDR_LEN)
482         addReply(c,shared.mbulkhdr[length]);
483     else
484         addReplyLongLongWithPrefix(c,length,'*');
485 }
486 
487 /* Create the length prefix of a bulk reply, example: $2234 */
488 void addReplyBulkLen(redisClient *c, robj *obj) {
489     size_t len;
490 
491     if (sdsEncodedObject(obj)) {
492         len = sdslen(obj->ptr);
493     } else {
494         long n = (long)obj->ptr;
495 
496         /* Compute how many bytes will take this integer as a radix 10 string */
497         len = 1;
498         if (n < 0) {
499             len++;
500             n = -n;
501         }
502         while((n = n/10) != 0) {
503             len++;
504         }
505     }
506 
507     if (len < REDIS_SHARED_BULKHDR_LEN)
508         addReply(c,shared.bulkhdr[len]);
509     else
510         addReplyLongLongWithPrefix(c,len,'$');
511 }
512 
513 /* Add a Redis Object as a bulk reply */
514 void addReplyBulk(redisClient *c, robj *obj) {
515     addReplyBulkLen(c,obj);
516     addReply(c,obj);
517     addReply(c,shared.crlf);
518 }
519 
520 /* Add a C buffer as bulk reply */
521 void addReplyBulkCBuffer(redisClient *c, void *p, size_t len) {
522     addReplyLongLongWithPrefix(c,len,'$');
523     addReplyString(c,p,len);
524     addReply(c,shared.crlf);
525 }
526 
527 /* Add a C nul term string as bulk reply */
528 void addReplyBulkCString(redisClient *c, char *s) {
529     if (s == NULL) {
530         addReply(c,shared.nullbulk);
531     } else {
532         addReplyBulkCBuffer(c,s,strlen(s));
533     }
534 }
535 
536 /* Add a long long as a bulk reply */
537 void addReplyBulkLongLong(redisClient *c, long long ll) {
538     char buf[64];
539     int len;
540 
541     len = ll2string(buf,64,ll);
542     addReplyBulkCBuffer(c,buf,len);
543 }
544 
545 /* Copy 'src' client output buffers into 'dst' client output buffers.
546  * The function takes care of freeing the old output buffers of the
547  * destination client. */
548 void copyClientOutputBuffer(redisClient *dst, redisClient *src) {
549     listRelease(dst->reply);
550     dst->reply = listDup(src->reply);
551     memcpy(dst->buf,src->buf,src->bufpos);
552     dst->bufpos = src->bufpos;
553     dst->reply_bytes = src->reply_bytes;
554 }
555 
556 #define MAX_ACCEPTS_PER_CALL 1000
557 static void acceptCommonHandler(int fd, int flags) {
558     redisClient *c;
559     if ((c = createClient(fd)) == NULL) {
560         redisLog(REDIS_WARNING,
561             "Error registering fd event for the new client: %s (fd=%d)",
562             strerror(errno),fd);
563         close(fd); /* May be already closed, just ignore errors */
564         return;
565     }
566     /* If maxclient directive is set and this is one client more... close the
567      * connection. Note that we create the client instead to check before
568      * for this condition, since now the socket is already set in non-blocking
569      * mode and we can send an error for free using the Kernel I/O */
570     if (listLength(server.clients) > server.maxclients) {
571         char *err = "-ERR max number of clients reached\r\n";
572 
573         /* That's a best effort error message, don't check write errors */
574         if (write(c->fd,err,strlen(err)) == -1) {
575             /* Nothing to do, Just to avoid the warning... */
576         }
577         server.stat_rejected_conn++;
578         freeClient(c);
579         return;
580     }
581     server.stat_numconnections++;
582     c->flags |= flags;
583 }
584 
585 void acceptTcpHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
586     int cport, cfd, max = MAX_ACCEPTS_PER_CALL;
587     char cip[REDIS_IP_STR_LEN];
588     REDIS_NOTUSED(el);
589     REDIS_NOTUSED(mask);
590     REDIS_NOTUSED(privdata);
591 
592     while(max--) {
593         cfd = anetTcpAccept(server.neterr, fd, cip, sizeof(cip), &cport);
594         if (cfd == ANET_ERR) {
595             if (errno != EWOULDBLOCK)
596                 redisLog(REDIS_WARNING,
597                     "Accepting client connection: %s", server.neterr);
598             return;
599         }
600         redisLog(REDIS_VERBOSE,"Accepted %s:%d", cip, cport);
601         acceptCommonHandler(cfd,0);
602     }
603 }
604 
605 void acceptUnixHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
606     int cfd, max = MAX_ACCEPTS_PER_CALL;
607     REDIS_NOTUSED(el);
608     REDIS_NOTUSED(mask);
609     REDIS_NOTUSED(privdata);
610 
611     while(max--) {
612         cfd = anetUnixAccept(server.neterr, fd);
613         if (cfd == ANET_ERR) {
614             if (errno != EWOULDBLOCK)
615                 redisLog(REDIS_WARNING,
616                     "Accepting client connection: %s", server.neterr);
617             return;
618         }
619         redisLog(REDIS_VERBOSE,"Accepted connection to %s", server.unixsocket);
620         acceptCommonHandler(cfd,REDIS_UNIX_SOCKET);
621     }
622 }
623 
624 static void freeClientArgv(redisClient *c) {
625     int j;
626     for (j = 0; j < c->argc; j++)
627         decrRefCount(c->argv[j]);
628     c->argc = 0;
629     c->cmd = NULL;
630 }
631 
632 /* Close all the slaves connections. This is useful in chained replication
633  * when we resync with our own master and want to force all our slaves to
634  * resync with us as well. */
635 void disconnectSlaves(void) {
636     while (listLength(server.slaves)) {
637         listNode *ln = listFirst(server.slaves);
638         freeClient((redisClient*)ln->value);
639     }
640 }
641 
642 /* This function is called when the slave lose the connection with the
643  * master into an unexpected way. */
644 void replicationHandleMasterDisconnection(void) {
645     server.master = NULL;
646     server.repl_state = REDIS_REPL_CONNECT;
647     server.repl_down_since = server.unixtime;
648     /* We lost connection with our master, force our slaves to resync
649      * with us as well to load the new data set.
650      *
651      * If server.masterhost is NULL the user called SLAVEOF NO ONE so
652      * slave resync is not needed. */
653     if (server.masterhost != NULL) disconnectSlaves();
654 }
655 
656 void freeClient(redisClient *c) {
657     listNode *ln;
658 
659     /* If this is marked as current client unset it */
660     if (server.current_client == c) server.current_client = NULL;
661 
662     /* If it is our master that's beging disconnected we should make sure
663      * to cache the state to try a partial resynchronization later.
664      *
665      * Note that before doing this we make sure that the client is not in
666      * some unexpected state, by checking its flags. */
667     if (server.master && c->flags & REDIS_MASTER) {
668         redisLog(REDIS_WARNING,"Connection with master lost.");
669         if (!(c->flags & (REDIS_CLOSE_AFTER_REPLY|
670                           REDIS_CLOSE_ASAP|
671                           REDIS_BLOCKED|
672                           REDIS_UNBLOCKED)))
673         {
674             replicationCacheMaster(c);
675             return;
676         }
677     }
678 
679     /* Log link disconnection with slave */
680     if ((c->flags & REDIS_SLAVE) && !(c->flags & REDIS_MONITOR)) {
681         char ip[REDIS_IP_STR_LEN];
682 
683         if (anetPeerToString(c->fd,ip,sizeof(ip),NULL) != -1) {
684             redisLog(REDIS_WARNING,"Connection with slave %s:%d lost.",
685                 ip, c->slave_listening_port);
686         }
687     }
688 
689     /* Free the query buffer */
690     sdsfree(c->querybuf);
691     c->querybuf = NULL;
692 
693     /* Deallocate structures used to block on blocking ops. */
694     if (c->flags & REDIS_BLOCKED) unblockClient(c);
695     dictRelease(c->bpop.keys);
696 
697     /* UNWATCH all the keys */
698     unwatchAllKeys(c);
699     listRelease(c->watched_keys);
700 
701     /* Unsubscribe from all the pubsub channels */
702     pubsubUnsubscribeAllChannels(c,0);
703     pubsubUnsubscribeAllPatterns(c,0);
704     dictRelease(c->pubsub_channels);
705     listRelease(c->pubsub_patterns);
706 
707     /* Close socket, unregister events, and remove list of replies and
708      * accumulated arguments. */
709     if (c->fd != -1) {
710         aeDeleteFileEvent(server.el,c->fd,AE_READABLE);
711         aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
712         close(c->fd);
713     }
714     listRelease(c->reply);
715     freeClientArgv(c);
716 
717     /* Remove from the list of clients */
718     if (c->fd != -1) {
719         ln = listSearchKey(server.clients,c);
720         redisAssert(ln != NULL);
721         listDelNode(server.clients,ln);
722     }
723 
724     /* When client was just unblocked because of a blocking operation,
725      * remove it from the list of unblocked clients. */
726     if (c->flags & REDIS_UNBLOCKED) {
727         ln = listSearchKey(server.unblocked_clients,c);
728         redisAssert(ln != NULL);
729         listDelNode(server.unblocked_clients,ln);
730     }
731 
732     /* Master/slave cleanup Case 1:
733      * we lost the connection with a slave. */
734     if (c->flags & REDIS_SLAVE) {
735         if (c->replstate == REDIS_REPL_SEND_BULK) {
736             if (c->repldbfd != -1) close(c->repldbfd);
737             if (c->replpreamble) sdsfree(c->replpreamble);
738         }
739         list *l = (c->flags & REDIS_MONITOR) ? server.monitors : server.slaves;
740         ln = listSearchKey(l,c);
741         redisAssert(ln != NULL);
742         listDelNode(l,ln);
743         /* We need to remember the time when we started to have zero
744          * attached slaves, as after some time we'll free the replication
745          * backlog. */
746         if (c->flags & REDIS_SLAVE && listLength(server.slaves) == 0)
747             server.repl_no_slaves_since = server.unixtime;
748         refreshGoodSlavesCount();
749     }
750 
751     /* Master/slave cleanup Case 2:
752      * we lost the connection with the master. */
753     if (c->flags & REDIS_MASTER) replicationHandleMasterDisconnection();
754 
755     /* If this client was scheduled for async freeing we need to remove it
756      * from the queue. */
757     if (c->flags & REDIS_CLOSE_ASAP) {
758         ln = listSearchKey(server.clients_to_close,c);
759         redisAssert(ln != NULL);
760         listDelNode(server.clients_to_close,ln);
761     }
762 
763     /* Release other dynamically allocated client structure fields,
764      * and finally release the client structure itself. */
765     if (c->name) decrRefCount(c->name);
766     zfree(c->argv);
767     freeClientMultiState(c);
768     sdsfree(c->peerid);
769     zfree(c);
770 }
771 
772 /* Schedule a client to free it at a safe time in the serverCron() function.
773  * This function is useful when we need to terminate a client but we are in
774  * a context where calling freeClient() is not possible, because the client
775  * should be valid for the continuation of the flow of the program. */
776 void freeClientAsync(redisClient *c) {
777     if (c->flags & REDIS_CLOSE_ASAP) return;
778     c->flags |= REDIS_CLOSE_ASAP;
779     listAddNodeTail(server.clients_to_close,c);
780 }
781 
782 void freeClientsInAsyncFreeQueue(void) {
783     while (listLength(server.clients_to_close)) {
784         listNode *ln = listFirst(server.clients_to_close);
785         redisClient *c = listNodeValue(ln);
786 
787         c->flags &= ~REDIS_CLOSE_ASAP;
788         freeClient(c);
789         listDelNode(server.clients_to_close,ln);
790     }
791 }
792 
793 void sendReplyToClient(aeEventLoop *el, int fd, void *privdata, int mask) {
794     redisClient *c = privdata;
795     int nwritten = 0, totwritten = 0, objlen;
796     size_t objmem;
797     robj *o;
798     REDIS_NOTUSED(el);
799     REDIS_NOTUSED(mask);
800 
801     while(c->bufpos > 0 || listLength(c->reply)) {
802         if (c->bufpos > 0) {
803             nwritten = write(fd,c->buf+c->sentlen,c->bufpos-c->sentlen);
804             if (nwritten <= 0) break;
805             c->sentlen += nwritten;
806             totwritten += nwritten;
807 
808             /* If the buffer was sent, set bufpos to zero to continue with
809              * the remainder of the reply. */
810             if (c->sentlen == c->bufpos) {
811                 c->bufpos = 0;
812                 c->sentlen = 0;
813             }
814         } else {
815             o = listNodeValue(listFirst(c->reply));
816             objlen = sdslen(o->ptr);
817             objmem = getStringObjectSdsUsedMemory(o);
818 
819             if (objlen == 0) {
820                 listDelNode(c->reply,listFirst(c->reply));
821                 c->reply_bytes -= objmem;
822                 continue;
823             }
824 
825             nwritten = write(fd, ((char*)o->ptr)+c->sentlen,objlen-c->sentlen);
826             if (nwritten <= 0) break;
827             c->sentlen += nwritten;
828             totwritten += nwritten;
829 
830             /* If we fully sent the object on head go to the next one */
831             if (c->sentlen == objlen) {
832                 listDelNode(c->reply,listFirst(c->reply));
833                 c->sentlen = 0;
834                 c->reply_bytes -= objmem;
835             }
836         }
837         /* Note that we avoid to send more than REDIS_MAX_WRITE_PER_EVENT
838          * bytes, in a single threaded server it's a good idea to serve
839          * other clients as well, even if a very large request comes from
840          * super fast link that is always able to accept data (in real world
841          * scenario think about 'KEYS *' against the loopback interface).
842          *
843          * However if we are over the maxmemory limit we ignore that and
844          * just deliver as much data as it is possible to deliver. */
845         if (totwritten > REDIS_MAX_WRITE_PER_EVENT &&
846             (server.maxmemory == 0 ||
847              zmalloc_used_memory() < server.maxmemory)) break;
848     }
849     if (nwritten == -1) {
850         if (errno == EAGAIN) {
851             nwritten = 0;
852         } else {
853             redisLog(REDIS_VERBOSE,
854                 "Error writing to client: %s", strerror(errno));
855             freeClient(c);
856             return;
857         }
858     }
859     if (totwritten > 0) {
860         /* For clients representing masters we don't count sending data
861          * as an interaction, since we always send REPLCONF ACK commands
862          * that take some time to just fill the socket output buffer.
863          * We just rely on data / pings received for timeout detection. */
864         if (!(c->flags & REDIS_MASTER)) c->lastinteraction = server.unixtime;
865     }
866     if (c->bufpos == 0 && listLength(c->reply) == 0) {
867         c->sentlen = 0;
868         aeDeleteFileEvent(server.el,c->fd,AE_WRITABLE);
869 
870         /* Close connection after entire reply has been sent. */
871         if (c->flags & REDIS_CLOSE_AFTER_REPLY) freeClient(c);
872     }
873 }
874 
875 /* resetClient prepare the client to process the next command */
876 void resetClient(redisClient *c) {
877     redisCommandProc *prevcmd = c->cmd ? c->cmd->proc : NULL;
878 
879     freeClientArgv(c);
880     c->reqtype = 0;
881     c->multibulklen = 0;
882     c->bulklen = -1;
883     /* We clear the ASKING flag as well if we are not inside a MULTI, and
884      * if what we just executed is not the ASKING command itself. */
885     if (!(c->flags & REDIS_MULTI) && prevcmd != askingCommand)
886         c->flags &= (~REDIS_ASKING);
887 }
888 
889 int processInlineBuffer(redisClient *c) {
890     char *newline;
891     int argc, j;
892     sds *argv, aux;
893     size_t querylen;
894 
895     /* Search for end of line */
896     newline = strchr(c->querybuf,'\n');
897 
898     /* Nothing to do without a \r\n */
899     if (newline == NULL) {
900         if (sdslen(c->querybuf) > REDIS_INLINE_MAX_SIZE) {
901             addReplyError(c,"Protocol error: too big inline request");
902             setProtocolError(c,0);
903         }
904         return REDIS_ERR;
905     }
906 
907     /* Handle the \r\n case. */
908     if (newline && newline != c->querybuf && *(newline-1) == '\r')
909         newline--;
910 
911     /* Split the input buffer up to the \r\n */
912     querylen = newline-(c->querybuf);
913     aux = sdsnewlen(c->querybuf,querylen);
914     argv = sdssplitargs(aux,&argc);
915     sdsfree(aux);
916     if (argv == NULL) {
917         addReplyError(c,"Protocol error: unbalanced quotes in request");
918         setProtocolError(c,0);
919         return REDIS_ERR;
920     }
921 
922     /* Newline from slaves can be used to refresh the last ACK time.
923      * This is useful for a slave to ping back while loading a big
924      * RDB file. */
925     if (querylen == 0 && c->flags & REDIS_SLAVE)
926         c->repl_ack_time = server.unixtime;
927 
928     /* Leave data after the first line of the query in the buffer */
929     sdsrange(c->querybuf,querylen+2,-1);
930 
931     /* Setup argv array on client structure */
932     if (c->argv) zfree(c->argv);
933     c->argv = zmalloc(sizeof(robj*)*argc);
934 
935     /* Create redis objects for all arguments. */
936     for (c->argc = 0, j = 0; j < argc; j++) {
937         if (sdslen(argv[j])) {
938             c->argv[c->argc] = createObject(REDIS_STRING,argv[j]);
939             c->argc++;
940         } else {
941             sdsfree(argv[j]);
942         }
943     }
944     zfree(argv);
945     return REDIS_OK;
946 }
947 
948 /* Helper function. Trims query buffer to make the function that processes
949  * multi bulk requests idempotent. */
950 static void setProtocolError(redisClient *c, int pos) {
951     if (server.verbosity >= REDIS_VERBOSE) {
952         sds client = catClientInfoString(sdsempty(),c);
953         redisLog(REDIS_VERBOSE,
954             "Protocol error from client: %s", client);
955         sdsfree(client);
956     }
957     c->flags |= REDIS_CLOSE_AFTER_REPLY;
958     sdsrange(c->querybuf,pos,-1);
959 }
960 
961 int processMultibulkBuffer(redisClient *c) {
962     char *newline = NULL;
963     int pos = 0, ok;
964     long long ll;
965 
966     if (c->multibulklen == 0) {
967         /* The client should have been reset */
968         redisAssertWithInfo(c,NULL,c->argc == 0);
969 
970         /* Multi bulk length cannot be read without a \r\n */
971         newline = strchr(c->querybuf,'\r');
972         if (newline == NULL) {
973             if (sdslen(c->querybuf) > REDIS_INLINE_MAX_SIZE) {
974                 addReplyError(c,"Protocol error: too big mbulk count string");
975                 setProtocolError(c,0);
976             }
977             return REDIS_ERR;
978         }
979 
980         /* Buffer should also contain \n */
981         if (newline-(c->querybuf) > ((signed)sdslen(c->querybuf)-2))
982             return REDIS_ERR;
983 
984         /* We know for sure there is a whole line since newline != NULL,
985          * so go ahead and find out the multi bulk length. */
986         redisAssertWithInfo(c,NULL,c->querybuf[0] == '*');
987         ok = string2ll(c->querybuf+1,newline-(c->querybuf+1),&ll);
988         if (!ok || ll > 1024*1024) {
989             addReplyError(c,"Protocol error: invalid multibulk length");
990             setProtocolError(c,pos);
991             return REDIS_ERR;
992         }
993 
994         pos = (newline-c->querybuf)+2;
995         if (ll <= 0) {
996             sdsrange(c->querybuf,pos,-1);
997             return REDIS_OK;
998         }
999 
1000         c->multibulklen = ll;
1001 
1002         /* Setup argv array on client structure */
1003         if (c->argv) zfree(c->argv);
1004         c->argv = zmalloc(sizeof(robj*)*c->multibulklen);
1005     }
1006 
1007     redisAssertWithInfo(c,NULL,c->multibulklen > 0);
1008     while(c->multibulklen) {
1009         /* Read bulk length if unknown */
1010         if (c->bulklen == -1) {
1011             newline = strchr(c->querybuf+pos,'\r');
1012             if (newline == NULL) {
1013                 if (sdslen(c->querybuf) > REDIS_INLINE_MAX_SIZE) {
1014                     addReplyError(c,
1015                         "Protocol error: too big bulk count string");
1016                     setProtocolError(c,0);
1017                     return REDIS_ERR;
1018                 }
1019                 break;
1020             }
1021 
1022             /* Buffer should also contain \n */
1023             if (newline-(c->querybuf) > ((signed)sdslen(c->querybuf)-2))
1024                 break;
1025 
1026             if (c->querybuf[pos] != '$') {
1027                 addReplyErrorFormat(c,
1028                     "Protocol error: expected '$', got '%c'",
1029                     c->querybuf[pos]);
1030                 setProtocolError(c,pos);
1031                 return REDIS_ERR;
1032             }
1033 
1034             ok = string2ll(c->querybuf+pos+1,newline-(c->querybuf+pos+1),&ll);
1035             if (!ok || ll < 0 || ll > 512*1024*1024) {
1036                 addReplyError(c,"Protocol error: invalid bulk length");
1037                 setProtocolError(c,pos);
1038                 return REDIS_ERR;
1039             }
1040 
1041             pos += newline-(c->querybuf+pos)+2;
1042             if (ll >= REDIS_MBULK_BIG_ARG) {
1043                 size_t qblen;
1044 
1045                 /* If we are going to read a large object from network
1046                  * try to make it likely that it will start at c->querybuf
1047                  * boundary so that we can optimize object creation
1048                  * avoiding a large copy of data. */
1049                 sdsrange(c->querybuf,pos,-1);
1050                 pos = 0;
1051                 qblen = sdslen(c->querybuf);
1052                 /* Hint the sds library about the amount of bytes this string is
1053                  * going to contain. */
1054                 if (qblen < (size_t)ll+2)
1055                     c->querybuf = sdsMakeRoomFor(c->querybuf,ll+2-qblen);
1056             }
1057             c->bulklen = ll;
1058         }
1059 
1060         /* Read bulk argument */
1061         if (sdslen(c->querybuf)-pos < (unsigned)(c->bulklen+2)) {
1062             /* Not enough data (+2 == trailing \r\n) */
1063             break;
1064         } else {
1065             /* Optimization: if the buffer contains JUST our bulk element
1066              * instead of creating a new object by *copying* the sds we
1067              * just use the current sds string. */
1068             if (pos == 0 &&
1069                 c->bulklen >= REDIS_MBULK_BIG_ARG &&
1070                 (signed) sdslen(c->querybuf) == c->bulklen+2)
1071             {
1072                 c->argv[c->argc++] = createObject(REDIS_STRING,c->querybuf);
1073                 sdsIncrLen(c->querybuf,-2); /* remove CRLF */
1074                 c->querybuf = sdsempty();
1075                 /* Assume that if we saw a fat argument we'll see another one
1076                  * likely... */
1077                 c->querybuf = sdsMakeRoomFor(c->querybuf,c->bulklen+2);
1078                 pos = 0;
1079             } else {
1080                 c->argv[c->argc++] =
1081                     createStringObject(c->querybuf+pos,c->bulklen);
1082                 pos += c->bulklen+2;
1083             }
1084             c->bulklen = -1;
1085             c->multibulklen--;
1086         }
1087     }
1088 
1089     /* Trim to pos */
1090     if (pos) sdsrange(c->querybuf,pos,-1);
1091 
1092     /* We're done when c->multibulk == 0 */
1093     if (c->multibulklen == 0) return REDIS_OK;
1094 
1095     /* Still not read to process the command */
1096     return REDIS_ERR;
1097 }
1098 
1099 void processInputBuffer(redisClient *c) {
1100     /* Keep processing while there is something in the input buffer */
1101     while(sdslen(c->querybuf)) {
1102         /* Return if clients are paused. */
1103         if (!(c->flags & REDIS_SLAVE) && clientsArePaused()) return;
1104 
1105         /* Immediately abort if the client is in the middle of something. */
1106         if (c->flags & REDIS_BLOCKED) return;
1107 
1108         /* REDIS_CLOSE_AFTER_REPLY closes the connection once the reply is
1109          * written to the client. Make sure to not let the reply grow after
1110          * this flag has been set (i.e. don't process more commands). */
1111         if (c->flags & REDIS_CLOSE_AFTER_REPLY) return;
1112 
1113         /* Determine request type when unknown. */
1114         if (!c->reqtype) {
1115             if (c->querybuf[0] == '*') {
1116                 c->reqtype = REDIS_REQ_MULTIBULK;
1117             } else {
1118                 c->reqtype = REDIS_REQ_INLINE;
1119             }
1120         }
1121 
1122         if (c->reqtype == REDIS_REQ_INLINE) {
1123             if (processInlineBuffer(c) != REDIS_OK) break;
1124         } else if (c->reqtype == REDIS_REQ_MULTIBULK) {
1125             if (processMultibulkBuffer(c) != REDIS_OK) break;
1126         } else {
1127             redisPanic("Unknown request type");
1128         }
1129 
1130         /* Multibulk processing could see a <= 0 length. */
1131         if (c->argc == 0) {
1132             resetClient(c);
1133         } else {
1134             /* Only reset the client when the command was executed. */
1135             if (processCommand(c) == REDIS_OK)
1136                 resetClient(c);
1137         }
1138     }
1139 }
1140 
1141 void readQueryFromClient(aeEventLoop *el, int fd, void *privdata, int mask) {
1142     redisClient *c = (redisClient*) privdata;
1143     int nread, readlen;
1144     size_t qblen;
1145     REDIS_NOTUSED(el);
1146     REDIS_NOTUSED(mask);
1147 
1148     server.current_client = c;
1149     readlen = REDIS_IOBUF_LEN;
1150     /* If this is a multi bulk request, and we are processing a bulk reply
1151      * that is large enough, try to maximize the probability that the query
1152      * buffer contains exactly the SDS string representing the object, even
1153      * at the risk of requiring more read(2) calls. This way the function
1154      * processMultiBulkBuffer() can avoid copying buffers to create the
1155      * Redis Object representing the argument. */
1156     if (c->reqtype == REDIS_REQ_MULTIBULK && c->multibulklen && c->bulklen != -1
1157         && c->bulklen >= REDIS_MBULK_BIG_ARG)
1158     {
1159         int remaining = (unsigned)(c->bulklen+2)-sdslen(c->querybuf);
1160 
1161         if (remaining < readlen) readlen = remaining;
1162     }
1163 
1164     qblen = sdslen(c->querybuf);
1165     if (c->querybuf_peak < qblen) c->querybuf_peak = qblen;
1166     c->querybuf = sdsMakeRoomFor(c->querybuf, readlen);
1167     nread = read(fd, c->querybuf+qblen, readlen);
1168     if (nread == -1) {
1169         if (errno == EAGAIN) {
1170             nread = 0;
1171         } else {
1172             redisLog(REDIS_VERBOSE, "Reading from client: %s",strerror(errno));
1173             freeClient(c);
1174             return;
1175         }
1176     } else if (nread == 0) {
1177         redisLog(REDIS_VERBOSE, "Client closed connection");
1178         freeClient(c);
1179         return;
1180     }
1181     if (nread) {
1182         sdsIncrLen(c->querybuf,nread);
1183         c->lastinteraction = server.unixtime;
1184         if (c->flags & REDIS_MASTER) c->reploff += nread;
1185     } else {
1186         server.current_client = NULL;
1187         return;
1188     }
1189     if (sdslen(c->querybuf) > server.client_max_querybuf_len) {
1190         sds ci = catClientInfoString(sdsempty(),c), bytes = sdsempty();
1191 
1192         bytes = sdscatrepr(bytes,c->querybuf,64);
1193         redisLog(REDIS_WARNING,"Closing client that reached max query buffer length: %s (qbuf initial bytes: %s)", ci, bytes);
1194         sdsfree(ci);
1195         sdsfree(bytes);
1196         freeClient(c);
1197         return;
1198     }
1199     processInputBuffer(c);
1200     server.current_client = NULL;
1201 }
1202 
1203 void getClientsMaxBuffers(unsigned long *longest_output_list,
1204                           unsigned long *biggest_input_buffer) {
1205     redisClient *c;
1206     listNode *ln;
1207     listIter li;
1208     unsigned long lol = 0, bib = 0;
1209 
1210     listRewind(server.clients,&li);
1211     while ((ln = listNext(&li)) != NULL) {
1212         c = listNodeValue(ln);
1213 
1214         if (listLength(c->reply) > lol) lol = listLength(c->reply);
1215         if (sdslen(c->querybuf) > bib) bib = sdslen(c->querybuf);
1216     }
1217     *longest_output_list = lol;
1218     *biggest_input_buffer = bib;
1219 }
1220 
1221 /* This is a helper function for genClientPeerId().
1222  * It writes the specified ip/port to "peerid" as a null termiated string
1223  * in the form ip:port if ip does not contain ":" itself, otherwise
1224  * [ip]:port format is used (for IPv6 addresses basically). */
1225 void formatPeerId(char *peerid, size_t peerid_len, char *ip, int port) {
1226     if (strchr(ip,':'))
1227         snprintf(peerid,peerid_len,"[%s]:%d",ip,port);
1228     else
1229         snprintf(peerid,peerid_len,"%s:%d",ip,port);
1230 }
1231 
1232 /* A Redis "Peer ID" is a colon separated ip:port pair.
1233  * For IPv4 it's in the form x.y.z.k:pork, example: "127.0.0.1:1234".
1234  * For IPv6 addresses we use [] around the IP part, like in "[::1]:1234".
1235  * For Unix socekts we use path:0, like in "/tmp/redis:0".
1236  *
1237  * A Peer ID always fits inside a buffer of REDIS_PEER_ID_LEN bytes, including
1238  * the null term.
1239  *
1240  * The function returns REDIS_OK on succcess, and REDIS_ERR on failure.
1241  *
1242  * On failure the function still populates 'peerid' with the "?:0" string
1243  * in case you want to relax error checking or need to display something
1244  * anyway (see anetPeerToString implementation for more info). */
1245 int genClientPeerId(redisClient *client, char *peerid, size_t peerid_len) {
1246     char ip[REDIS_IP_STR_LEN];
1247     int port;
1248 
1249     if (client->flags & REDIS_UNIX_SOCKET) {
1250         /* Unix socket client. */
1251         snprintf(peerid,peerid_len,"%s:0",server.unixsocket);
1252         return REDIS_OK;
1253     } else {
1254         /* TCP client. */
1255         int retval = anetPeerToString(client->fd,ip,sizeof(ip),&port);
1256         formatPeerId(peerid,peerid_len,ip,port);
1257         return (retval == -1) ? REDIS_ERR : REDIS_OK;
1258     }
1259 }
1260 
1261 /* This function returns the client peer id, by creating and caching it
1262  * if client->perrid is NULL, otherwise returning the cached value.
1263  * The Peer ID never changes during the life of the client, however it
1264  * is expensive to compute. */
1265 char *getClientPeerId(redisClient *c) {
1266     char peerid[REDIS_PEER_ID_LEN];
1267 
1268     if (c->peerid == NULL) {
1269         genClientPeerId(c,peerid,sizeof(peerid));
1270         c->peerid = sdsnew(peerid);
1271     }
1272     return c->peerid;
1273 }
1274 
1275 /* Concatenate a string representing the state of a client in an human
1276  * readable format, into the sds string 's'. */
1277 sds catClientInfoString(sds s, redisClient *client) {
1278     char flags[16], events[3], *p;
1279     int emask;
1280 
1281     p = flags;
1282     if (client->flags & REDIS_SLAVE) {
1283         if (client->flags & REDIS_MONITOR)
1284             *p++ = 'O';
1285         else
1286             *p++ = 'S';
1287     }
1288     if (client->flags & REDIS_MASTER) *p++ = 'M';
1289     if (client->flags & REDIS_MULTI) *p++ = 'x';
1290     if (client->flags & REDIS_BLOCKED) *p++ = 'b';
1291     if (client->flags & REDIS_DIRTY_CAS) *p++ = 'd';
1292     if (client->flags & REDIS_CLOSE_AFTER_REPLY) *p++ = 'c';
1293     if (client->flags & REDIS_UNBLOCKED) *p++ = 'u';
1294     if (client->flags & REDIS_CLOSE_ASAP) *p++ = 'A';
1295     if (client->flags & REDIS_UNIX_SOCKET) *p++ = 'U';
1296     if (client->flags & REDIS_READONLY) *p++ = 'r';
1297     if (p == flags) *p++ = 'N';
1298     *p++ = '\0';
1299 
1300     emask = client->fd == -1 ? 0 : aeGetFileEvents(server.el,client->fd);
1301     p = events;
1302     if (emask & AE_READABLE) *p++ = 'r';
1303     if (emask & AE_WRITABLE) *p++ = 'w';
1304     *p = '\0';
1305     return sdscatfmt(s,
1306         "id=%U addr=%s fd=%i name=%s age=%I idle=%I flags=%s db=%i sub=%i psub=%i multi=%i qbuf=%U qbuf-free=%U obl=%U oll=%U omem=%U events=%s cmd=%s",
1307         (unsigned long long) client->id,
1308         getClientPeerId(client),
1309         client->fd,
1310         client->name ? (char*)client->name->ptr : "",
1311         (long long)(server.unixtime - client->ctime),
1312         (long long)(server.unixtime - client->lastinteraction),
1313         flags,
1314         client->db->id,
1315         (int) dictSize(client->pubsub_channels),
1316         (int) listLength(client->pubsub_patterns),
1317         (client->flags & REDIS_MULTI) ? client->mstate.count : -1,
1318         (unsigned long long) sdslen(client->querybuf),
1319         (unsigned long long) sdsavail(client->querybuf),
1320         (unsigned long long) client->bufpos,
1321         (unsigned long long) listLength(client->reply),
1322         (unsigned long long) getClientOutputBufferMemoryUsage(client),
1323         events,
1324         client->lastcmd ? client->lastcmd->name : "NULL");
1325 }
1326 
1327 sds getAllClientsInfoString(void) {
1328     listNode *ln;
1329     listIter li;
1330     redisClient *client;
1331     sds o = sdsempty();
1332 
1333     o = sdsMakeRoomFor(o,200*listLength(server.clients));
1334     listRewind(server.clients,&li);
1335     while ((ln = listNext(&li)) != NULL) {
1336         client = listNodeValue(ln);
1337         o = catClientInfoString(o,client);
1338         o = sdscatlen(o,"\n",1);
1339     }
1340     return o;
1341 }
1342 
1343 void clientCommand(redisClient *c) {
1344     listNode *ln;
1345     listIter li;
1346     redisClient *client;
1347 
1348     if (!strcasecmp(c->argv[1]->ptr,"list") && c->argc == 2) {
1349         /* CLIENT LIST */
1350         sds o = getAllClientsInfoString();
1351         addReplyBulkCBuffer(c,o,sdslen(o));
1352         sdsfree(o);
1353     } else if (!strcasecmp(c->argv[1]->ptr,"kill")) {
1354         /* CLIENT KILL <ip:port>
1355          * CLIENT KILL <option> [value] ... <option> [value] */
1356         char *addr = NULL;
1357         int type = -1;
1358         uint64_t id = 0;
1359         int skipme = 1;
1360         int killed = 0, close_this_client = 0;
1361 
1362         if (c->argc == 3) {
1363             /* Old style syntax: CLIENT KILL <addr> */
1364             addr = c->argv[2]->ptr;
1365             skipme = 0; /* With the old form, you can kill yourself. */
1366         } else if (c->argc > 3) {
1367             int i = 2; /* Next option index. */
1368 
1369             /* New style syntax: parse options. */
1370             while(i < c->argc) {
1371                 int moreargs = c->argc > i+1;
1372 
1373                 if (!strcasecmp(c->argv[i]->ptr,"id") && moreargs) {
1374                     long long tmp;
1375 
1376                     if (getLongLongFromObjectOrReply(c,c->argv[i+1],&tmp,NULL)
1377                         != REDIS_OK) return;
1378                     id = tmp;
1379                 } else if (!strcasecmp(c->argv[i]->ptr,"type") && moreargs) {
1380                     type = getClientTypeByName(c->argv[i+1]->ptr);
1381                     if (type == -1) {
1382                         addReplyErrorFormat(c,"Unknown client type '%s'",
1383                             (char*) c->argv[i+1]->ptr);
1384                         return;
1385                     }
1386                 } else if (!strcasecmp(c->argv[i]->ptr,"addr") && moreargs) {
1387                     addr = c->argv[i+1]->ptr;
1388                 } else if (!strcasecmp(c->argv[i]->ptr,"skipme") && moreargs) {
1389                     if (!strcasecmp(c->argv[i+1]->ptr,"yes")) {
1390                         skipme = 1;
1391                     } else if (!strcasecmp(c->argv[i+1]->ptr,"no")) {
1392                         skipme = 0;
1393                     } else {
1394                         addReply(c,shared.syntaxerr);
1395                         return;
1396                     }
1397                 } else {
1398                     addReply(c,shared.syntaxerr);
1399                     return;
1400                 }
1401                 i += 2;
1402             }
1403         } else {
1404             addReply(c,shared.syntaxerr);
1405             return;
1406         }
1407 
1408         /* Iterate clients killing all the matching clients. */
1409         listRewind(server.clients,&li);
1410         while ((ln = listNext(&li)) != NULL) {
1411             client = listNodeValue(ln);
1412             if (addr && strcmp(getClientPeerId(client),addr) != 0) continue;
1413             if (type != -1 &&
1414                 (client->flags & REDIS_MASTER ||
1415                  getClientType(client) != type)) continue;
1416             if (id != 0 && client->id != id) continue;
1417             if (c == client && skipme) continue;
1418 
1419             /* Kill it. */
1420             if (c == client) {
1421                 close_this_client = 1;
1422             } else {
1423                 freeClient(client);
1424             }
1425             killed++;
1426         }
1427 
1428         /* Reply according to old/new format. */
1429         if (c->argc == 3) {
1430             if (killed == 0)
1431                 addReplyError(c,"No such client");
1432             else
1433                 addReply(c,shared.ok);
1434         } else {
1435             addReplyLongLong(c,killed);
1436         }
1437 
1438         /* If this client has to be closed, flag it as CLOSE_AFTER_REPLY
1439          * only after we queued the reply to its output buffers. */
1440         if (close_this_client) c->flags |= REDIS_CLOSE_AFTER_REPLY;
1441     } else if (!strcasecmp(c->argv[1]->ptr,"setname") && c->argc == 3) {
1442         int j, len = sdslen(c->argv[2]->ptr);
1443         char *p = c->argv[2]->ptr;
1444 
1445         /* Setting the client name to an empty string actually removes
1446          * the current name. */
1447         if (len == 0) {
1448             if (c->name) decrRefCount(c->name);
1449             c->name = NULL;
1450             addReply(c,shared.ok);
1451             return;
1452         }
1453 
1454         /* Otherwise check if the charset is ok. We need to do this otherwise
1455          * CLIENT LIST format will break. You should always be able to
1456          * split by space to get the different fields. */
1457         for (j = 0; j < len; j++) {
1458             if (p[j] < '!' || p[j] > '~') { /* ASCII is assumed. */
1459                 addReplyError(c,
1460                     "Client names cannot contain spaces, "
1461                     "newlines or special characters.");
1462                 return;
1463             }
1464         }
1465         if (c->name) decrRefCount(c->name);
1466         c->name = c->argv[2];
1467         incrRefCount(c->name);
1468         addReply(c,shared.ok);
1469     } else if (!strcasecmp(c->argv[1]->ptr,"getname") && c->argc == 2) {
1470         if (c->name)
1471             addReplyBulk(c,c->name);
1472         else
1473             addReply(c,shared.nullbulk);
1474     } else if (!strcasecmp(c->argv[1]->ptr,"pause") && c->argc == 3) {
1475         long long duration;
1476 
1477         if (getTimeoutFromObjectOrReply(c,c->argv[2],&duration,UNIT_MILLISECONDS)
1478                                         != REDIS_OK) return;
1479         pauseClients(duration);
1480         addReply(c,shared.ok);
1481     } else {
1482         addReplyError(c, "Syntax error, try CLIENT (LIST | KILL ip:port | GETNAME | SETNAME connection-name)");
1483     }
1484 }
1485 
1486 /* Rewrite the command vector of the client. All the new objects ref count
1487  * is incremented. The old command vector is freed, and the old objects
1488  * ref count is decremented. */
1489 void rewriteClientCommandVector(redisClient *c, int argc, ...) {
1490     va_list ap;
1491     int j;
1492     robj **argv; /* The new argument vector */
1493 
1494     argv = zmalloc(sizeof(robj*)*argc);
1495     va_start(ap,argc);
1496     for (j = 0; j < argc; j++) {
1497         robj *a;
1498 
1499         a = va_arg(ap, robj*);
1500         argv[j] = a;
1501         incrRefCount(a);
1502     }
1503     /* We free the objects in the original vector at the end, so we are
1504      * sure that if the same objects are reused in the new vector the
1505      * refcount gets incremented before it gets decremented. */
1506     for (j = 0; j < c->argc; j++) decrRefCount(c->argv[j]);
1507     zfree(c->argv);
1508     /* Replace argv and argc with our new versions. */
1509     c->argv = argv;
1510     c->argc = argc;
1511     c->cmd = lookupCommandOrOriginal(c->argv[0]->ptr);
1512     redisAssertWithInfo(c,NULL,c->cmd != NULL);
1513     va_end(ap);
1514 }
1515 
1516 /* Rewrite a single item in the command vector.
1517  * The new val ref count is incremented, and the old decremented. */
1518 void rewriteClientCommandArgument(redisClient *c, int i, robj *newval) {
1519     robj *oldval;
1520 
1521     redisAssertWithInfo(c,NULL,i < c->argc);
1522     oldval = c->argv[i];
1523     c->argv[i] = newval;
1524     incrRefCount(newval);
1525     decrRefCount(oldval);
1526 
1527     /* If this is the command name make sure to fix c->cmd. */
1528     if (i == 0) {
1529         c->cmd = lookupCommandOrOriginal(c->argv[0]->ptr);
1530         redisAssertWithInfo(c,NULL,c->cmd != NULL);
1531     }
1532 }
1533 
1534 /* This function returns the number of bytes that Redis is virtually
1535  * using to store the reply still not read by the client.
1536  * It is "virtual" since the reply output list may contain objects that
1537  * are shared and are not really using additional memory.
1538  *
1539  * The function returns the total sum of the length of all the objects
1540  * stored in the output list, plus the memory used to allocate every
1541  * list node. The static reply buffer is not taken into account since it
1542  * is allocated anyway.
1543  *
1544  * Note: this function is very fast so can be called as many time as
1545  * the caller wishes. The main usage of this function currently is
1546  * enforcing the client output length limits. */
1547 unsigned long getClientOutputBufferMemoryUsage(redisClient *c) {
1548     unsigned long list_item_size = sizeof(listNode)+sizeof(robj);
1549 
1550     return c->reply_bytes + (list_item_size*listLength(c->reply));
1551 }
1552 
1553 /* Get the class of a client, used in order to enforce limits to different
1554  * classes of clients.
1555  *
1556  * The function will return one of the following:
1557  * REDIS_CLIENT_TYPE_NORMAL -> Normal client
1558  * REDIS_CLIENT_TYPE_SLAVE  -> Slave or client executing MONITOR command
1559  * REDIS_CLIENT_TYPE_PUBSUB -> Client subscribed to Pub/Sub channels
1560  */
1561 int getClientType(redisClient *c) {
1562     if ((c->flags & REDIS_SLAVE) && !(c->flags & REDIS_MONITOR))
1563         return REDIS_CLIENT_TYPE_SLAVE;
1564     if (c->flags & REDIS_PUBSUB)
1565         return REDIS_CLIENT_TYPE_PUBSUB;
1566     return REDIS_CLIENT_TYPE_NORMAL;
1567 }
1568 
1569 int getClientTypeByName(char *name) {
1570     if (!strcasecmp(name,"normal")) return REDIS_CLIENT_TYPE_NORMAL;
1571     else if (!strcasecmp(name,"slave")) return REDIS_CLIENT_TYPE_SLAVE;
1572     else if (!strcasecmp(name,"pubsub")) return REDIS_CLIENT_TYPE_PUBSUB;
1573     else return -1;
1574 }
1575 
1576 char *getClientTypeName(int class) {
1577     switch(class) {
1578     case REDIS_CLIENT_TYPE_NORMAL: return "normal";
1579     case REDIS_CLIENT_TYPE_SLAVE:  return "slave";
1580     case REDIS_CLIENT_TYPE_PUBSUB: return "pubsub";
1581     default:                       return NULL;
1582     }
1583 }
1584 
1585 /* The function checks if the client reached output buffer soft or hard
1586  * limit, and also update the state needed to check the soft limit as
1587  * a side effect.
1588  *
1589  * Return value: non-zero if the client reached the soft or the hard limit.
1590  *               Otherwise zero is returned. */
1591 int checkClientOutputBufferLimits(redisClient *c) {
1592     int soft = 0, hard = 0, class;
1593     unsigned long used_mem = getClientOutputBufferMemoryUsage(c);
1594 
1595     class = getClientType(c);
1596     if (server.client_obuf_limits[class].hard_limit_bytes &&
1597         used_mem >= server.client_obuf_limits[class].hard_limit_bytes)
1598         hard = 1;
1599     if (server.client_obuf_limits[class].soft_limit_bytes &&
1600         used_mem >= server.client_obuf_limits[class].soft_limit_bytes)
1601         soft = 1;
1602 
1603     /* We need to check if the soft limit is reached continuously for the
1604      * specified amount of seconds. */
1605     if (soft) {
1606         if (c->obuf_soft_limit_reached_time == 0) {
1607             c->obuf_soft_limit_reached_time = server.unixtime;
1608             soft = 0; /* First time we see the soft limit reached */
1609         } else {
1610             time_t elapsed = server.unixtime - c->obuf_soft_limit_reached_time;
1611 
1612             if (elapsed <=
1613                 server.client_obuf_limits[class].soft_limit_seconds) {
1614                 soft = 0; /* The client still did not reached the max number of
1615                              seconds for the soft limit to be considered
1616                              reached. */
1617             }
1618         }
1619     } else {
1620         c->obuf_soft_limit_reached_time = 0;
1621     }
1622     return soft || hard;
1623 }
1624 
1625 /* Asynchronously close a client if soft or hard limit is reached on the
1626  * output buffer size. The caller can check if the client will be closed
1627  * checking if the client REDIS_CLOSE_ASAP flag is set.
1628  *
1629  * Note: we need to close the client asynchronously because this function is
1630  * called from contexts where the client can't be freed safely, i.e. from the
1631  * lower level functions pushing data inside the client output buffers. */
1632 void asyncCloseClientOnOutputBufferLimitReached(redisClient *c) {
1633     redisAssert(c->reply_bytes < ULONG_MAX-(1024*64));
1634     if (c->reply_bytes == 0 || c->flags & REDIS_CLOSE_ASAP) return;
1635     if (checkClientOutputBufferLimits(c)) {
1636         sds client = catClientInfoString(sdsempty(),c);
1637 
1638         freeClientAsync(c);
1639         redisLog(REDIS_WARNING,"Client %s scheduled to be closed ASAP for overcoming of output buffer limits.", client);
1640         sdsfree(client);
1641     }
1642 }
1643 
1644 /* Helper function used by freeMemoryIfNeeded() in order to flush slaves
1645  * output buffers without returning control to the event loop. */
1646 void flushSlavesOutputBuffers(void) {
1647     listIter li;
1648     listNode *ln;
1649 
1650     listRewind(server.slaves,&li);
1651     while((ln = listNext(&li))) {
1652         redisClient *slave = listNodeValue(ln);
1653         int events;
1654 
1655         events = aeGetFileEvents(server.el,slave->fd);
1656         if (events & AE_WRITABLE &&
1657             slave->replstate == REDIS_REPL_ONLINE &&
1658             listLength(slave->reply))
1659         {
1660             sendReplyToClient(server.el,slave->fd,slave,0);
1661         }
1662     }
1663 }
1664 
1665 /* Pause clients up to the specified unixtime (in ms). While clients
1666  * are paused no command is processed from clients, so the data set can't
1667  * change during that time.
1668  *
1669  * However while this function pauses normal and Pub/Sub clients, slaves are
1670  * still served, so this function can be used on server upgrades where it is
1671  * required that slaves process the latest bytes from the replication stream
1672  * before being turned to masters.
1673  *
1674  * This function is also internally used by Redis Cluster for the manual
1675  * failover procedure implemented by CLUSTER FAILOVER.
1676  *
1677  * The function always succeed, even if there is already a pause in progress.
1678  * In such a case, the pause is extended if the duration is more than the
1679  * time left for the previous duration. However if the duration is smaller
1680  * than the time left for the previous pause, no change is made to the
1681  * left duration. */
1682 void pauseClients(mstime_t end) {
1683     if (!server.clients_paused || end > server.clients_pause_end_time)
1684         server.clients_pause_end_time = end;
1685     server.clients_paused = 1;
1686 }
1687 
1688 /* Return non-zero if clients are currently paused. As a side effect the
1689  * function checks if the pause time was reached and clear it. */
1690 int clientsArePaused(void) {
1691     if (server.clients_paused && server.clients_pause_end_time < server.mstime) {
1692         listNode *ln;
1693         listIter li;
1694         redisClient *c;
1695 
1696         server.clients_paused = 0;
1697 
1698         /* Put all the clients in the unblocked clients queue in order to
1699          * force the re-processing of the input buffer if any. */
1700         listRewind(server.clients,&li);
1701         while ((ln = listNext(&li)) != NULL) {
1702             c = listNodeValue(ln);
1703 
1704             if (c->flags & REDIS_SLAVE) continue;
1705             listAddNodeTail(server.unblocked_clients,c);
1706         }
1707     }
1708     return server.clients_paused;
1709 }
1710 
1711 /* This function is called by Redis in order to process a few events from
1712  * time to time while blocked into some not interruptible operation.
1713  * This allows to reply to clients with the -LOADING error while loading the
1714  * data set at startup or after a full resynchronization with the master
1715  * and so forth.
1716  *
1717  * It calls the event loop in order to process a few events. Specifically we
1718  * try to call the event loop for times as long as we receive acknowledge that
1719  * some event was processed, in order to go forward with the accept, read,
1720  * write, close sequence needed to serve a client.
1721  *
1722  * The function returns the total number of events processed. */
1723 int processEventsWhileBlocked(void) {
1724     int iterations = 4; /* See the function top-comment. */
1725     int count = 0;
1726     while (iterations--) {
1727         int events = aeProcessEvents(server.el, AE_FILE_EVENTS|AE_DONT_WAIT);
1728         if (!events) break;
1729         count += events;
1730     }
1731     return count;
1732 }
1733