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redis/src/db.c

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/*
* Copyright (c) 2009-2012, 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 "atomicvar.h"
#include <signal.h>
#include <ctype.h>
/*-----------------------------------------------------------------------------
* C-level DB API
*----------------------------------------------------------------------------*/
/* Low level key lookup API, not actually called directly from commands
* implementations that should instead rely on lookupKeyRead(),
* lookupKeyWrite() and lookupKeyReadWithFlags(). */
robj *lookupKey(redisDb *db, robj *key, int flags) {
dictEntry *de = dictFind(db->dict,key->ptr);
if (de) {
robj *val = dictGetVal(de);
/* Update the access time for the ageing algorithm.
* Don't do it if we have a saving child, as this will trigger
* a copy on write madness. */
if (server.rdb_child_pid == -1 &&
server.aof_child_pid == -1 &&
!(flags & LOOKUP_NOTOUCH))
{
if (server.maxmemory_policy & MAXMEMORY_FLAG_LFU) {
unsigned long ldt = val->lru >> 8;
unsigned long counter = LFULogIncr(val->lru & 255);
val->lru = (ldt << 8) | counter;
} else {
val->lru = LRU_CLOCK();
}
}
return val;
} else {
return NULL;
}
}
/* Lookup a key for read operations, or return NULL if the key is not found
* in the specified DB.
*
* As a side effect of calling this function:
* 1. A key gets expired if it reached it's TTL.
* 2. The key last access time is updated.
* 3. The global keys hits/misses stats are updated (reported in INFO).
*
* This API should not be used when we write to the key after obtaining
* the object linked to the key, but only for read only operations.
*
* Flags change the behavior of this command:
*
* LOOKUP_NONE (or zero): no special flags are passed.
* LOOKUP_NOTOUCH: don't alter the last access time of the key.
*
* Note: this function also returns NULL is the key is logically expired
* but still existing, in case this is a slave, since this API is called only
* for read operations. Even if the key expiry is master-driven, we can
* correctly report a key is expired on slaves even if the master is lagging
* expiring our key via DELs in the replication link. */
robj *lookupKeyReadWithFlags(redisDb *db, robj *key, int flags) {
robj *val;
if (expireIfNeeded(db,key) == 1) {
/* Key expired. If we are in the context of a master, expireIfNeeded()
* returns 0 only when the key does not exist at all, so it's safe
* to return NULL ASAP. */
if (server.masterhost == NULL) return NULL;
/* However if we are in the context of a slave, expireIfNeeded() will
* not really try to expire the key, it only returns information
* about the "logical" status of the key: key expiring is up to the
* master in order to have a consistent view of master's data set.
*
* However, if the command caller is not the master, and as additional
* safety measure, the command invoked is a read-only command, we can
* safely return NULL here, and provide a more consistent behavior
* to clients accessign expired values in a read-only fashion, that
* will say the key as non existing.
*
* Notably this covers GETs when slaves are used to scale reads. */
if (server.current_client &&
server.current_client != server.master &&
server.current_client->cmd &&
server.current_client->cmd->flags & CMD_READONLY)
{
return NULL;
}
}
val = lookupKey(db,key,flags);
if (val == NULL)
server.stat_keyspace_misses++;
else
server.stat_keyspace_hits++;
return val;
}
/* Like lookupKeyReadWithFlags(), but does not use any flag, which is the
* common case. */
robj *lookupKeyRead(redisDb *db, robj *key) {
return lookupKeyReadWithFlags(db,key,LOOKUP_NONE);
}
/* Lookup a key for write operations, and as a side effect, if needed, expires
* the key if its TTL is reached.
*
* Returns the linked value object if the key exists or NULL if the key
* does not exist in the specified DB. */
robj *lookupKeyWrite(redisDb *db, robj *key) {
expireIfNeeded(db,key);
return lookupKey(db,key,LOOKUP_NONE);
}
robj *lookupKeyReadOrReply(client *c, robj *key, robj *reply) {
robj *o = lookupKeyRead(c->db, key);
if (!o) addReply(c,reply);
return o;
}
robj *lookupKeyWriteOrReply(client *c, robj *key, robj *reply) {
robj *o = lookupKeyWrite(c->db, key);
if (!o) addReply(c,reply);
return o;
}
/* Add the key to the DB. It's up to the caller to increment the reference
* counter of the value if needed.
*
* The program is aborted if the key already exists. */
void dbAdd(redisDb *db, robj *key, robj *val) {
sds copy = sdsdup(key->ptr);
int retval = dictAdd(db->dict, copy, val);
serverAssertWithInfo(NULL,key,retval == DICT_OK);
if (val->type == OBJ_LIST) signalListAsReady(db, key);
if (server.cluster_enabled) slotToKeyAdd(key);
}
/* Overwrite an existing key with a new value. Incrementing the reference
* count of the new value is up to the caller.
* This function does not modify the expire time of the existing key.
*
* The program is aborted if the key was not already present. */
void dbOverwrite(redisDb *db, robj *key, robj *val) {
dictEntry *de = dictFind(db->dict,key->ptr);
serverAssertWithInfo(NULL,key,de != NULL);
if (server.maxmemory_policy & MAXMEMORY_FLAG_LFU) {
robj *old = dictGetVal(de);
int saved_lru = old->lru;
dictReplace(db->dict, key->ptr, val);
val->lru = saved_lru;
} else {
dictReplace(db->dict, key->ptr, val);
}
}
/* High level Set operation. This function can be used in order to set
* a key, whatever it was existing or not, to a new object.
*
* 1) The ref count of the value object is incremented.
* 2) clients WATCHing for the destination key notified.
* 3) The expire time of the key is reset (the key is made persistent).
*
* All the new keys in the database should be craeted via this interface. */
void setKey(redisDb *db, robj *key, robj *val) {
if (lookupKeyWrite(db,key) == NULL) {
dbAdd(db,key,val);
} else {
dbOverwrite(db,key,val);
}
incrRefCount(val);
removeExpire(db,key);
signalModifiedKey(db,key);
}
int dbExists(redisDb *db, robj *key) {
return dictFind(db->dict,key->ptr) != NULL;
}
/* Return a random key, in form of a Redis object.
* If there are no keys, NULL is returned.
*
* The function makes sure to return keys not already expired. */
robj *dbRandomKey(redisDb *db) {
dictEntry *de;
while(1) {
sds key;
robj *keyobj;
de = dictGetRandomKey(db->dict);
if (de == NULL) return NULL;
key = dictGetKey(de);
keyobj = createStringObject(key,sdslen(key));
if (dictFind(db->expires,key)) {
if (expireIfNeeded(db,keyobj)) {
decrRefCount(keyobj);
continue; /* search for another key. This expired. */
}
}
return keyobj;
}
}
/* Delete a key, value, and associated expiration entry if any, from the DB */
int dbSyncDelete(redisDb *db, robj *key) {
/* Deleting an entry from the expires dict will not free the sds of
* the key, because it is shared with the main dictionary. */
if (dictSize(db->expires) > 0) dictDelete(db->expires,key->ptr);
if (dictDelete(db->dict,key->ptr) == DICT_OK) {
if (server.cluster_enabled) slotToKeyDel(key);
return 1;
} else {
return 0;
}
}
/* This is a wrapper whose behavior depends on the Redis lazy free
* configuration. Deletes the key synchronously or asynchronously. */
int dbDelete(redisDb *db, robj *key) {
return server.lazyfree_lazy_server_del ? dbAsyncDelete(db,key) :
dbSyncDelete(db,key);
}
/* Prepare the string object stored at 'key' to be modified destructively
* to implement commands like SETBIT or APPEND.
*
* An object is usually ready to be modified unless one of the two conditions
* are true:
*
* 1) The object 'o' is shared (refcount > 1), we don't want to affect
* other users.
* 2) The object encoding is not "RAW".
*
* If the object is found in one of the above conditions (or both) by the
* function, an unshared / not-encoded copy of the string object is stored
* at 'key' in the specified 'db'. Otherwise the object 'o' itself is
* returned.
*
* USAGE:
*
* The object 'o' is what the caller already obtained by looking up 'key'
* in 'db', the usage pattern looks like this:
*
* o = lookupKeyWrite(db,key);
* if (checkType(c,o,OBJ_STRING)) return;
* o = dbUnshareStringValue(db,key,o);
*
* At this point the caller is ready to modify the object, for example
* using an sdscat() call to append some data, or anything else.
*/
robj *dbUnshareStringValue(redisDb *db, robj *key, robj *o) {
serverAssert(o->type == OBJ_STRING);
if (o->refcount != 1 || o->encoding != OBJ_ENCODING_RAW) {
robj *decoded = getDecodedObject(o);
o = createRawStringObject(decoded->ptr, sdslen(decoded->ptr));
decrRefCount(decoded);
dbOverwrite(db,key,o);
}
return o;
}
/* Remove all keys from all the databases in a Redis server.
* If callback is given the function is called from time to time to
* signal that work is in progress.
*
* The dbnum can be -1 if all the DBs should be flushed, or the specified
* DB number if we want to flush only a single Redis database number.
*
* Flags are be EMPTYDB_NO_FLAGS if no special flags are specified or
* EMPTYDB_ASYNC if we want the memory to be freed in a different thread
* and the function to return ASAP.
*
* On success the fuction returns the number of keys removed from the
* database(s). Otherwise -1 is returned in the specific case the
* DB number is out of range, and errno is set to EINVAL. */
long long emptyDb(int dbnum, int flags, void(callback)(void*)) {
int j, async = (flags & EMPTYDB_ASYNC);
long long removed = 0;
if (dbnum < -1 || dbnum >= server.dbnum) {
errno = EINVAL;
return -1;
}
for (j = 0; j < server.dbnum; j++) {
if (dbnum != -1 && dbnum != j) continue;
removed += dictSize(server.db[j].dict);
if (async) {
emptyDbAsync(&server.db[j]);
} else {
dictEmpty(server.db[j].dict,callback);
dictEmpty(server.db[j].expires,callback);
}
}
if (server.cluster_enabled) {
if (async) {
slotToKeyFlushAsync();
} else {
slotToKeyFlush();
}
}
if (dbnum == -1) flushSlaveKeysWithExpireList();
return removed;
}
int selectDb(client *c, int id) {
if (id < 0 || id >= server.dbnum)
return C_ERR;
c->db = &server.db[id];
return C_OK;
}
/*-----------------------------------------------------------------------------
* Hooks for key space changes.
*
* Every time a key in the database is modified the function
* signalModifiedKey() is called.
*
* Every time a DB is flushed the function signalFlushDb() is called.
*----------------------------------------------------------------------------*/
void signalModifiedKey(redisDb *db, robj *key) {
touchWatchedKey(db,key);
}
void signalFlushedDb(int dbid) {
touchWatchedKeysOnFlush(dbid);
}
/*-----------------------------------------------------------------------------
* Type agnostic commands operating on the key space
*----------------------------------------------------------------------------*/
/* Return the set of flags to use for the emptyDb() call for FLUSHALL
* and FLUSHDB commands.
*
* Currently the command just attempts to parse the "ASYNC" option. It
* also checks if the command arity is wrong.
*
* On success C_OK is returned and the flags are stored in *flags, otherwise
* C_ERR is returned and the function sends an error to the client. */
int getFlushCommandFlags(client *c, int *flags) {
/* Parse the optional ASYNC option. */
if (c->argc > 1) {
if (c->argc > 2 || strcasecmp(c->argv[1]->ptr,"async")) {
addReply(c,shared.syntaxerr);
return C_ERR;
}
*flags = EMPTYDB_ASYNC;
} else {
*flags = EMPTYDB_NO_FLAGS;
}
return C_OK;
}
/* FLUSHDB [ASYNC]
*
* Flushes the currently SELECTed Redis DB. */
void flushdbCommand(client *c) {
int flags;
if (getFlushCommandFlags(c,&flags) == C_ERR) return;
signalFlushedDb(c->db->id);
server.dirty += emptyDb(c->db->id,flags,NULL);
addReply(c,shared.ok);
}
/* FLUSHALL [ASYNC]
*
* Flushes the whole server data set. */
void flushallCommand(client *c) {
int flags;
if (getFlushCommandFlags(c,&flags) == C_ERR) return;
signalFlushedDb(-1);
server.dirty += emptyDb(-1,flags,NULL);
addReply(c,shared.ok);
if (server.rdb_child_pid != -1) {
kill(server.rdb_child_pid,SIGUSR1);
rdbRemoveTempFile(server.rdb_child_pid);
}
if (server.saveparamslen > 0) {
/* Normally rdbSave() will reset dirty, but we don't want this here
* as otherwise FLUSHALL will not be replicated nor put into the AOF. */
int saved_dirty = server.dirty;
rdbSave(server.rdb_filename,NULL);
server.dirty = saved_dirty;
}
server.dirty++;
}
/* This command implements DEL and LAZYDEL. */
void delGenericCommand(client *c, int lazy) {
int numdel = 0, j;
for (j = 1; j < c->argc; j++) {
expireIfNeeded(c->db,c->argv[j]);
int deleted = lazy ? dbAsyncDelete(c->db,c->argv[j]) :
dbSyncDelete(c->db,c->argv[j]);
if (deleted) {
signalModifiedKey(c->db,c->argv[j]);
notifyKeyspaceEvent(NOTIFY_GENERIC,
"del",c->argv[j],c->db->id);
server.dirty++;
numdel++;
}
}
addReplyLongLong(c,numdel);
}
void delCommand(client *c) {
delGenericCommand(c,0);
}
void unlinkCommand(client *c) {
delGenericCommand(c,1);
}
/* EXISTS key1 key2 ... key_N.
* Return value is the number of keys existing. */
void existsCommand(client *c) {
long long count = 0;
int j;
for (j = 1; j < c->argc; j++) {
expireIfNeeded(c->db,c->argv[j]);
if (dbExists(c->db,c->argv[j])) count++;
}
addReplyLongLong(c,count);
}
void selectCommand(client *c) {
long id;
if (getLongFromObjectOrReply(c, c->argv[1], &id,
"invalid DB index") != C_OK)
return;
if (server.cluster_enabled && id != 0) {
addReplyError(c,"SELECT is not allowed in cluster mode");
return;
}
if (selectDb(c,id) == C_ERR) {
addReplyError(c,"DB index is out of range");
} else {
addReply(c,shared.ok);
}
}
void randomkeyCommand(client *c) {
robj *key;
if ((key = dbRandomKey(c->db)) == NULL) {
addReply(c,shared.nullbulk);
return;
}
addReplyBulk(c,key);
decrRefCount(key);
}
void keysCommand(client *c) {
dictIterator *di;
dictEntry *de;
sds pattern = c->argv[1]->ptr;
int plen = sdslen(pattern), allkeys;
unsigned long numkeys = 0;
void *replylen = addDeferredMultiBulkLength(c);
di = dictGetSafeIterator(c->db->dict);
allkeys = (pattern[0] == '*' && pattern[1] == '\0');
while((de = dictNext(di)) != NULL) {
sds key = dictGetKey(de);
robj *keyobj;
if (allkeys || stringmatchlen(pattern,plen,key,sdslen(key),0)) {
keyobj = createStringObject(key,sdslen(key));
if (expireIfNeeded(c->db,keyobj) == 0) {
addReplyBulk(c,keyobj);
numkeys++;
}
decrRefCount(keyobj);
}
}
dictReleaseIterator(di);
setDeferredMultiBulkLength(c,replylen,numkeys);
}
/* This callback is used by scanGenericCommand in order to collect elements
* returned by the dictionary iterator into a list. */
void scanCallback(void *privdata, const dictEntry *de) {
void **pd = (void**) privdata;
list *keys = pd[0];
robj *o = pd[1];
robj *key, *val = NULL;
if (o == NULL) {
sds sdskey = dictGetKey(de);
key = createStringObject(sdskey, sdslen(sdskey));
} else if (o->type == OBJ_SET) {
sds keysds = dictGetKey(de);
key = createStringObject(keysds,sdslen(keysds));
} else if (o->type == OBJ_HASH) {
sds sdskey = dictGetKey(de);
sds sdsval = dictGetVal(de);
key = createStringObject(sdskey,sdslen(sdskey));
val = createStringObject(sdsval,sdslen(sdsval));
} else if (o->type == OBJ_ZSET) {
sds sdskey = dictGetKey(de);
key = createStringObject(sdskey,sdslen(sdskey));
val = createStringObjectFromLongDouble(*(double*)dictGetVal(de),0);
} else {
serverPanic("Type not handled in SCAN callback.");
}
listAddNodeTail(keys, key);
if (val) listAddNodeTail(keys, val);
}
/* Try to parse a SCAN cursor stored at object 'o':
* if the cursor is valid, store it as unsigned integer into *cursor and
* returns C_OK. Otherwise return C_ERR and send an error to the
* client. */
int parseScanCursorOrReply(client *c, robj *o, unsigned long *cursor) {
char *eptr;
/* Use strtoul() because we need an *unsigned* long, so
* getLongLongFromObject() does not cover the whole cursor space. */
errno = 0;
*cursor = strtoul(o->ptr, &eptr, 10);
if (isspace(((char*)o->ptr)[0]) || eptr[0] != '\0' || errno == ERANGE)
{
addReplyError(c, "invalid cursor");
return C_ERR;
}
return C_OK;
}
/* This command implements SCAN, HSCAN and SSCAN commands.
* If object 'o' is passed, then it must be a Hash or Set object, otherwise
* if 'o' is NULL the command will operate on the dictionary associated with
* the current database.
*
* When 'o' is not NULL the function assumes that the first argument in
* the client arguments vector is a key so it skips it before iterating
* in order to parse options.
*
* In the case of a Hash object the function returns both the field and value
* of every element on the Hash. */
void scanGenericCommand(client *c, robj *o, unsigned long cursor) {
int i, j;
list *keys = listCreate();
listNode *node, *nextnode;
long count = 10;
sds pat = NULL;
int patlen = 0, use_pattern = 0;
dict *ht;
/* Object must be NULL (to iterate keys names), or the type of the object
* must be Set, Sorted Set, or Hash. */
serverAssert(o == NULL || o->type == OBJ_SET || o->type == OBJ_HASH ||
o->type == OBJ_ZSET);
/* Set i to the first option argument. The previous one is the cursor. */
i = (o == NULL) ? 2 : 3; /* Skip the key argument if needed. */
/* Step 1: Parse options. */
while (i < c->argc) {
j = c->argc - i;
if (!strcasecmp(c->argv[i]->ptr, "count") && j >= 2) {
if (getLongFromObjectOrReply(c, c->argv[i+1], &count, NULL)
!= C_OK)
{
goto cleanup;
}
if (count < 1) {
addReply(c,shared.syntaxerr);
goto cleanup;
}
i += 2;
} else if (!strcasecmp(c->argv[i]->ptr, "match") && j >= 2) {
pat = c->argv[i+1]->ptr;
patlen = sdslen(pat);
/* The pattern always matches if it is exactly "*", so it is
* equivalent to disabling it. */
use_pattern = !(pat[0] == '*' && patlen == 1);
i += 2;
} else {
addReply(c,shared.syntaxerr);
goto cleanup;
}
}
/* Step 2: Iterate the collection.
*
* Note that if the object is encoded with a ziplist, intset, or any other
* representation that is not a hash table, we are sure that it is also
* composed of a small number of elements. So to avoid taking state we
* just return everything inside the object in a single call, setting the
* cursor to zero to signal the end of the iteration. */
/* Handle the case of a hash table. */
ht = NULL;
if (o == NULL) {
ht = c->db->dict;
} else if (o->type == OBJ_SET && o->encoding == OBJ_ENCODING_HT) {
ht = o->ptr;
} else if (o->type == OBJ_HASH && o->encoding == OBJ_ENCODING_HT) {
ht = o->ptr;
count *= 2; /* We return key / value for this type. */
} else if (o->type == OBJ_ZSET && o->encoding == OBJ_ENCODING_SKIPLIST) {
zset *zs = o->ptr;
ht = zs->dict;
count *= 2; /* We return key / value for this type. */
}
if (ht) {
void *privdata[2];
/* We set the max number of iterations to ten times the specified
* COUNT, so if the hash table is in a pathological state (very
* sparsely populated) we avoid to block too much time at the cost
* of returning no or very few elements. */
long maxiterations = count*10;
/* We pass two pointers to the callback: the list to which it will
* add new elements, and the object containing the dictionary so that
* it is possible to fetch more data in a type-dependent way. */
privdata[0] = keys;
privdata[1] = o;
do {
cursor = dictScan(ht, cursor, scanCallback, NULL, privdata);
} while (cursor &&
maxiterations-- &&
listLength(keys) < (unsigned long)count);
} else if (o->type == OBJ_SET) {
int pos = 0;
int64_t ll;
while(intsetGet(o->ptr,pos++,&ll))
listAddNodeTail(keys,createStringObjectFromLongLong(ll));
cursor = 0;
} else if (o->type == OBJ_HASH || o->type == OBJ_ZSET) {
unsigned char *p = ziplistIndex(o->ptr,0);
unsigned char *vstr;
unsigned int vlen;
long long vll;
while(p) {
ziplistGet(p,&vstr,&vlen,&vll);
listAddNodeTail(keys,
(vstr != NULL) ? createStringObject((char*)vstr,vlen) :
createStringObjectFromLongLong(vll));
p = ziplistNext(o->ptr,p);
}
cursor = 0;
} else {
serverPanic("Not handled encoding in SCAN.");
}
/* Step 3: Filter elements. */
node = listFirst(keys);
while (node) {
robj *kobj = listNodeValue(node);
nextnode = listNextNode(node);
int filter = 0;
/* Filter element if it does not match the pattern. */
if (!filter && use_pattern) {
if (sdsEncodedObject(kobj)) {
if (!stringmatchlen(pat, patlen, kobj->ptr, sdslen(kobj->ptr), 0))
filter = 1;
} else {
char buf[LONG_STR_SIZE];
int len;
serverAssert(kobj->encoding == OBJ_ENCODING_INT);
len = ll2string(buf,sizeof(buf),(long)kobj->ptr);
if (!stringmatchlen(pat, patlen, buf, len, 0)) filter = 1;
}
}
/* Filter element if it is an expired key. */
if (!filter && o == NULL && expireIfNeeded(c->db, kobj)) filter = 1;
/* Remove the element and its associted value if needed. */
if (filter) {
decrRefCount(kobj);
listDelNode(keys, node);
}
/* If this is a hash or a sorted set, we have a flat list of
* key-value elements, so if this element was filtered, remove the
* value, or skip it if it was not filtered: we only match keys. */
if (o && (o->type == OBJ_ZSET || o->type == OBJ_HASH)) {
node = nextnode;
nextnode = listNextNode(node);
if (filter) {
kobj = listNodeValue(node);
decrRefCount(kobj);
listDelNode(keys, node);
}
}
node = nextnode;
}
/* Step 4: Reply to the client. */
addReplyMultiBulkLen(c, 2);
addReplyBulkLongLong(c,cursor);
addReplyMultiBulkLen(c, listLength(keys));
while ((node = listFirst(keys)) != NULL) {
robj *kobj = listNodeValue(node);
addReplyBulk(c, kobj);
decrRefCount(kobj);
listDelNode(keys, node);
}
cleanup:
listSetFreeMethod(keys,decrRefCountVoid);
listRelease(keys);
}
/* The SCAN command completely relies on scanGenericCommand. */
void scanCommand(client *c) {
unsigned long cursor;
if (parseScanCursorOrReply(c,c->argv[1],&cursor) == C_ERR) return;
scanGenericCommand(c,NULL,cursor);
}
void dbsizeCommand(client *c) {
addReplyLongLong(c,dictSize(c->db->dict));
}
void lastsaveCommand(client *c) {
addReplyLongLong(c,server.lastsave);
}
void typeCommand(client *c) {
robj *o;
char *type;
o = lookupKeyReadWithFlags(c->db,c->argv[1],LOOKUP_NOTOUCH);
if (o == NULL) {
type = "none";
} else {
switch(o->type) {
case OBJ_STRING: type = "string"; break;
case OBJ_LIST: type = "list"; break;
case OBJ_SET: type = "set"; break;
case OBJ_ZSET: type = "zset"; break;
case OBJ_HASH: type = "hash"; break;
case OBJ_MODULE: {
moduleValue *mv = o->ptr;
type = mv->type->name;
}; break;
default: type = "unknown"; break;
}
}
addReplyStatus(c,type);
}
void shutdownCommand(client *c) {
int flags = 0;
if (c->argc > 2) {
addReply(c,shared.syntaxerr);
return;
} else if (c->argc == 2) {
if (!strcasecmp(c->argv[1]->ptr,"nosave")) {
flags |= SHUTDOWN_NOSAVE;
} else if (!strcasecmp(c->argv[1]->ptr,"save")) {
flags |= SHUTDOWN_SAVE;
} else {
addReply(c,shared.syntaxerr);
return;
}
}
/* When SHUTDOWN is called while the server is loading a dataset in
* memory we need to make sure no attempt is performed to save
* the dataset on shutdown (otherwise it could overwrite the current DB
* with half-read data).
*
* Also when in Sentinel mode clear the SAVE flag and force NOSAVE. */
if (server.loading || server.sentinel_mode)
flags = (flags & ~SHUTDOWN_SAVE) | SHUTDOWN_NOSAVE;
if (prepareForShutdown(flags) == C_OK) exit(0);
addReplyError(c,"Errors trying to SHUTDOWN. Check logs.");
}
void renameGenericCommand(client *c, int nx) {
robj *o;
long long expire;
int samekey = 0;
/* When source and dest key is the same, no operation is performed,
* if the key exists, however we still return an error on unexisting key. */
if (sdscmp(c->argv[1]->ptr,c->argv[2]->ptr) == 0) samekey = 1;
if ((o = lookupKeyWriteOrReply(c,c->argv[1],shared.nokeyerr)) == NULL)
return;
if (samekey) {
addReply(c,nx ? shared.czero : shared.ok);
return;
}
incrRefCount(o);
expire = getExpire(c->db,c->argv[1]);
if (lookupKeyWrite(c->db,c->argv[2]) != NULL) {
if (nx) {
decrRefCount(o);
addReply(c,shared.czero);
return;
}
/* Overwrite: delete the old key before creating the new one
* with the same name. */
dbDelete(c->db,c->argv[2]);
}
dbAdd(c->db,c->argv[2],o);
if (expire != -1) setExpire(c,c->db,c->argv[2],expire);
dbDelete(c->db,c->argv[1]);
signalModifiedKey(c->db,c->argv[1]);
signalModifiedKey(c->db,c->argv[2]);
notifyKeyspaceEvent(NOTIFY_GENERIC,"rename_from",
c->argv[1],c->db->id);
notifyKeyspaceEvent(NOTIFY_GENERIC,"rename_to",
c->argv[2],c->db->id);
server.dirty++;
addReply(c,nx ? shared.cone : shared.ok);
}
void renameCommand(client *c) {
renameGenericCommand(c,0);
}
void renamenxCommand(client *c) {
renameGenericCommand(c,1);
}
void moveCommand(client *c) {
robj *o;
redisDb *src, *dst;
int srcid;
long long dbid, expire;
if (server.cluster_enabled) {
addReplyError(c,"MOVE is not allowed in cluster mode");
return;
}
/* Obtain source and target DB pointers */
src = c->db;
srcid = c->db->id;
if (getLongLongFromObject(c->argv[2],&dbid) == C_ERR ||
dbid < INT_MIN || dbid > INT_MAX ||
selectDb(c,dbid) == C_ERR)
{
addReply(c,shared.outofrangeerr);
return;
}
dst = c->db;
selectDb(c,srcid); /* Back to the source DB */
/* If the user is moving using as target the same
* DB as the source DB it is probably an error. */
if (src == dst) {
addReply(c,shared.sameobjecterr);
return;
}
/* Check if the element exists and get a reference */
o = lookupKeyWrite(c->db,c->argv[1]);
if (!o) {
addReply(c,shared.czero);
return;
}
expire = getExpire(c->db,c->argv[1]);
/* Return zero if the key already exists in the target DB */
if (lookupKeyWrite(dst,c->argv[1]) != NULL) {
addReply(c,shared.czero);
return;
}
dbAdd(dst,c->argv[1],o);
if (expire != -1) setExpire(c,dst,c->argv[1],expire);
incrRefCount(o);
/* OK! key moved, free the entry in the source DB */
dbDelete(src,c->argv[1]);
server.dirty++;
addReply(c,shared.cone);
}
/* Helper function for dbSwapDatabases(): scans the list of keys that have
* one or more blocked clients for B[LR]POP or other list blocking commands
* and signal the keys are ready if they are lists. See the comment where
* the function is used for more info. */
void scanDatabaseForReadyLists(redisDb *db) {
dictEntry *de;
dictIterator *di = dictGetSafeIterator(db->blocking_keys);
while((de = dictNext(di)) != NULL) {
robj *key = dictGetKey(de);
robj *value = lookupKey(db,key,LOOKUP_NOTOUCH);
if (value && value->type == OBJ_LIST)
signalListAsReady(db, key);
}
dictReleaseIterator(di);
}
/* Swap two databases at runtime so that all clients will magically see
* the new database even if already connected. Note that the client
* structure c->db points to a given DB, so we need to be smarter and
* swap the underlying referenced structures, otherwise we would need
* to fix all the references to the Redis DB structure.
*
* Returns C_ERR if at least one of the DB ids are out of range, otherwise
* C_OK is returned. */
int dbSwapDatabases(int id1, int id2) {
if (id1 < 0 || id1 >= server.dbnum ||
id2 < 0 || id2 >= server.dbnum) return C_ERR;
if (id1 == id2) return C_OK;
redisDb aux = server.db[id1];
redisDb *db1 = &server.db[id1], *db2 = &server.db[id2];
/* Swap hash tables. Note that we don't swap blocking_keys,
* ready_keys and watched_keys, since we want clients to
* remain in the same DB they were. */
db1->dict = db2->dict;
db1->expires = db2->expires;
db1->avg_ttl = db2->avg_ttl;
db2->dict = aux.dict;
db2->expires = aux.expires;
db2->avg_ttl = aux.avg_ttl;
/* Now we need to handle clients blocked on lists: as an effect
* of swapping the two DBs, a client that was waiting for list
* X in a given DB, may now actually be unblocked if X happens
* to exist in the new version of the DB, after the swap.
*
* However normally we only do this check for efficiency reasons
* in dbAdd() when a list is created. So here we need to rescan
* the list of clients blocked on lists and signal lists as ready
* if needed. */
scanDatabaseForReadyLists(db1);
scanDatabaseForReadyLists(db2);
return C_OK;
}
/* SWAPDB db1 db2 */
void swapdbCommand(client *c) {
long id1, id2;
/* Not allowed in cluster mode: we have just DB 0 there. */
if (server.cluster_enabled) {
addReplyError(c,"SWAPDB is not allowed in cluster mode");
return;
}
/* Get the two DBs indexes. */
if (getLongFromObjectOrReply(c, c->argv[1], &id1,
"invalid first DB index") != C_OK)
return;
if (getLongFromObjectOrReply(c, c->argv[2], &id2,
"invalid second DB index") != C_OK)
return;
/* Swap... */
if (dbSwapDatabases(id1,id2) == C_ERR) {
addReplyError(c,"DB index is out of range");
return;
} else {
server.dirty++;
addReply(c,shared.ok);
}
}
/*-----------------------------------------------------------------------------
* Expires API
*----------------------------------------------------------------------------*/
int removeExpire(redisDb *db, robj *key) {
/* An expire may only be removed if there is a corresponding entry in the
* main dict. Otherwise, the key will never be freed. */
serverAssertWithInfo(NULL,key,dictFind(db->dict,key->ptr) != NULL);
return dictDelete(db->expires,key->ptr) == DICT_OK;
}
/* Set an expire to the specified key. If the expire is set in the context
* of an user calling a command 'c' is the client, otherwise 'c' is set
* to NULL. The 'when' parameter is the absolute unix time in milliseconds
* after which the key will no longer be considered valid. */
void setExpire(client *c, redisDb *db, robj *key, long long when) {
dictEntry *kde, *de;
/* Reuse the sds from the main dict in the expire dict */
kde = dictFind(db->dict,key->ptr);
serverAssertWithInfo(NULL,key,kde != NULL);
de = dictAddOrFind(db->expires,dictGetKey(kde));
dictSetSignedIntegerVal(de,when);
int writable_slave = server.masterhost && server.repl_slave_ro == 0;
if (c && writable_slave && !(c->flags & CLIENT_MASTER))
rememberSlaveKeyWithExpire(db,key);
}
/* Return the expire time of the specified key, or -1 if no expire
* is associated with this key (i.e. the key is non volatile) */
long long getExpire(redisDb *db, robj *key) {
dictEntry *de;
/* No expire? return ASAP */
if (dictSize(db->expires) == 0 ||
(de = dictFind(db->expires,key->ptr)) == NULL) return -1;
/* The entry was found in the expire dict, this means it should also
* be present in the main dict (safety check). */
serverAssertWithInfo(NULL,key,dictFind(db->dict,key->ptr) != NULL);
return dictGetSignedIntegerVal(de);
}
/* Propagate expires into slaves and the AOF file.
* When a key expires in the master, a DEL operation for this key is sent
* to all the slaves and the AOF file if enabled.
*
* This way the key expiry is centralized in one place, and since both
* AOF and the master->slave link guarantee operation ordering, everything
* will be consistent even if we allow write operations against expiring
* keys. */
void propagateExpire(redisDb *db, robj *key, int lazy) {
robj *argv[2];
argv[0] = lazy ? shared.unlink : shared.del;
argv[1] = key;
incrRefCount(argv[0]);
incrRefCount(argv[1]);
if (server.aof_state != AOF_OFF)
feedAppendOnlyFile(server.delCommand,db->id,argv,2);
replicationFeedSlaves(server.slaves,db->id,argv,2);
decrRefCount(argv[0]);
decrRefCount(argv[1]);
}
int expireIfNeeded(redisDb *db, robj *key) {
mstime_t when = getExpire(db,key);
mstime_t now;
if (when < 0) return 0; /* No expire for this key */
/* Don't expire anything while loading. It will be done later. */
if (server.loading) return 0;
/* If we are in the context of a Lua script, we claim that time is
* blocked to when the Lua script started. This way a key can expire
* only the first time it is accessed and not in the middle of the
* script execution, making propagation to slaves / AOF consistent.
* See issue #1525 on Github for more information. */
now = server.lua_caller ? server.lua_time_start : mstime();
/* If we are running in the context of a slave, return ASAP:
* the slave key expiration is controlled by the master that will
* send us synthesized DEL operations for expired keys.
*
* Still we try to return the right information to the caller,
* that is, 0 if we think the key should be still valid, 1 if
* we think the key is expired at this time. */
if (server.masterhost != NULL) return now > when;
/* Return when this key has not expired */
if (now <= when) return 0;
/* Delete the key */
server.stat_expiredkeys++;
propagateExpire(db,key,server.lazyfree_lazy_expire);
notifyKeyspaceEvent(NOTIFY_EXPIRED,
"expired",key,db->id);
return server.lazyfree_lazy_expire ? dbAsyncDelete(db,key) :
dbSyncDelete(db,key);
}
/* -----------------------------------------------------------------------------
* API to get key arguments from commands
* ---------------------------------------------------------------------------*/
/* The base case is to use the keys position as given in the command table
* (firstkey, lastkey, step). */
int *getKeysUsingCommandTable(struct redisCommand *cmd,robj **argv, int argc, int *numkeys) {
int j, i = 0, last, *keys;
UNUSED(argv);
if (cmd->firstkey == 0) {
*numkeys = 0;
return NULL;
}
last = cmd->lastkey;
if (last < 0) last = argc+last;
keys = zmalloc(sizeof(int)*((last - cmd->firstkey)+1));
for (j = cmd->firstkey; j <= last; j += cmd->keystep) {
if (j >= argc) {
/* Modules command do not have dispatch time arity checks, so
* we need to handle the case where the user passed an invalid
* number of arguments here. In this case we return no keys
* and expect the module command to report an arity error. */
if (cmd->flags & CMD_MODULE) {
zfree(keys);
*numkeys = 0;
return NULL;
} else {
serverPanic("Redis built-in command declared keys positions not matching the arity requirements.");
}
}
keys[i++] = j;
}
*numkeys = i;
return keys;
}
/* Return all the arguments that are keys in the command passed via argc / argv.
*
* The command returns the positions of all the key arguments inside the array,
* so the actual return value is an heap allocated array of integers. The
* length of the array is returned by reference into *numkeys.
*
* 'cmd' must be point to the corresponding entry into the redisCommand
* table, according to the command name in argv[0].
*
* This function uses the command table if a command-specific helper function
* is not required, otherwise it calls the command-specific function. */
int *getKeysFromCommand(struct redisCommand *cmd, robj **argv, int argc, int *numkeys) {
if (cmd->flags & CMD_MODULE_GETKEYS) {
return moduleGetCommandKeysViaAPI(cmd,argv,argc,numkeys);
} else if (!(cmd->flags & CMD_MODULE) && cmd->getkeys_proc) {
return cmd->getkeys_proc(cmd,argv,argc,numkeys);
} else {
return getKeysUsingCommandTable(cmd,argv,argc,numkeys);
}
}
/* Free the result of getKeysFromCommand. */
void getKeysFreeResult(int *result) {
zfree(result);
}
/* Helper function to extract keys from following commands:
* ZUNIONSTORE <destkey> <num-keys> <key> <key> ... <key> <options>
* ZINTERSTORE <destkey> <num-keys> <key> <key> ... <key> <options> */
int *zunionInterGetKeys(struct redisCommand *cmd, robj **argv, int argc, int *numkeys) {
int i, num, *keys;
UNUSED(cmd);
num = atoi(argv[2]->ptr);
/* Sanity check. Don't return any key if the command is going to
* reply with syntax error. */
if (num > (argc-3)) {
*numkeys = 0;
return NULL;
}
/* Keys in z{union,inter}store come from two places:
* argv[1] = storage key,
* argv[3...n] = keys to intersect */
keys = zmalloc(sizeof(int)*(num+1));
/* Add all key positions for argv[3...n] to keys[] */
for (i = 0; i < num; i++) keys[i] = 3+i;
/* Finally add the argv[1] key position (the storage key target). */
keys[num] = 1;
*numkeys = num+1; /* Total keys = {union,inter} keys + storage key */
return keys;
}
/* Helper function to extract keys from the following commands:
* EVAL <script> <num-keys> <key> <key> ... <key> [more stuff]
* EVALSHA <script> <num-keys> <key> <key> ... <key> [more stuff] */
int *evalGetKeys(struct redisCommand *cmd, robj **argv, int argc, int *numkeys) {
int i, num, *keys;
UNUSED(cmd);
num = atoi(argv[2]->ptr);
/* Sanity check. Don't return any key if the command is going to
* reply with syntax error. */
if (num > (argc-3)) {
*numkeys = 0;
return NULL;
}
keys = zmalloc(sizeof(int)*num);
*numkeys = num;
/* Add all key positions for argv[3...n] to keys[] */
for (i = 0; i < num; i++) keys[i] = 3+i;
return keys;
}
/* Helper function to extract keys from the SORT command.
*
* SORT <sort-key> ... STORE <store-key> ...
*
* The first argument of SORT is always a key, however a list of options
* follow in SQL-alike style. Here we parse just the minimum in order to
* correctly identify keys in the "STORE" option. */
int *sortGetKeys(struct redisCommand *cmd, robj **argv, int argc, int *numkeys) {
int i, j, num, *keys, found_store = 0;
UNUSED(cmd);
num = 0;
keys = zmalloc(sizeof(int)*2); /* Alloc 2 places for the worst case. */
keys[num++] = 1; /* <sort-key> is always present. */
/* Search for STORE option. By default we consider options to don't
* have arguments, so if we find an unknown option name we scan the
* next. However there are options with 1 or 2 arguments, so we
* provide a list here in order to skip the right number of args. */
struct {
char *name;
int skip;
} skiplist[] = {
{"limit", 2},
{"get", 1},
{"by", 1},
{NULL, 0} /* End of elements. */
};
for (i = 2; i < argc; i++) {
for (j = 0; skiplist[j].name != NULL; j++) {
if (!strcasecmp(argv[i]->ptr,skiplist[j].name)) {
i += skiplist[j].skip;
break;
} else if (!strcasecmp(argv[i]->ptr,"store") && i+1 < argc) {
/* Note: we don't increment "num" here and continue the loop
* to be sure to process the *last* "STORE" option if multiple
* ones are provided. This is same behavior as SORT. */
found_store = 1;
keys[num] = i+1; /* <store-key> */
break;
}
}
}
*numkeys = num + found_store;
return keys;
}
int *migrateGetKeys(struct redisCommand *cmd, robj **argv, int argc, int *numkeys) {
int i, num, first, *keys;
UNUSED(cmd);
/* Assume the obvious form. */
first = 3;
num = 1;
/* But check for the extended one with the KEYS option. */
if (argc > 6) {
for (i = 6; i < argc; i++) {
if (!strcasecmp(argv[i]->ptr,"keys") &&
sdslen(argv[3]->ptr) == 0)
{
first = i+1;
num = argc-first;
break;
}
}
}
keys = zmalloc(sizeof(int)*num);
for (i = 0; i < num; i++) keys[i] = first+i;
*numkeys = num;
return keys;
}
/* Helper function to extract keys from following commands:
* GEORADIUS key x y radius unit [WITHDIST] [WITHHASH] [WITHCOORD] [ASC|DESC]
* [COUNT count] [STORE key] [STOREDIST key]
* GEORADIUSBYMEMBER key member radius unit ... options ... */
int *georadiusGetKeys(struct redisCommand *cmd, robj **argv, int argc, int *numkeys) {
int i, num, *keys;
UNUSED(cmd);
/* Check for the presence of the stored key in the command */
int stored_key = -1;
for (i = 5; i < argc; i++) {
char *arg = argv[i]->ptr;
/* For the case when user specifies both "store" and "storedist" options, the
* second key specified would override the first key. This behavior is kept
* the same as in georadiusCommand method.
*/
if ((!strcasecmp(arg, "store") || !strcasecmp(arg, "storedist")) && ((i+1) < argc)) {
stored_key = i+1;
i++;
}
}
num = 1 + (stored_key == -1 ? 0 : 1);
/* Keys in the command come from two places:
* argv[1] = key,
* argv[5...n] = stored key if present
*/
keys = zmalloc(sizeof(int) * num);
/* Add all key positions to keys[] */
keys[0] = 1;
if(num > 1) {
keys[1] = stored_key;
}
*numkeys = num;
return keys;
}
/* Slot to Key API. This is used by Redis Cluster in order to obtain in
* a fast way a key that belongs to a specified hash slot. This is useful
* while rehashing the cluster and in other conditions when we need to
* understand if we have keys for a given hash slot. */
void slotToKeyUpdateKey(robj *key, int add) {
unsigned int hashslot = keyHashSlot(key->ptr,sdslen(key->ptr));
unsigned char buf[64];
unsigned char *indexed = buf;
size_t keylen = sdslen(key->ptr);
server.cluster->slots_keys_count[hashslot] += add ? 1 : -1;
if (keylen+2 > 64) indexed = zmalloc(keylen+2);
indexed[0] = (hashslot >> 8) & 0xff;
indexed[1] = hashslot & 0xff;
memcpy(indexed+2,key->ptr,keylen);
if (add) {
raxInsert(server.cluster->slots_to_keys,indexed,keylen+2,NULL,NULL);
} else {
raxRemove(server.cluster->slots_to_keys,indexed,keylen+2,NULL);
}
if (indexed != buf) zfree(indexed);
}
void slotToKeyAdd(robj *key) {
slotToKeyUpdateKey(key,1);
}
void slotToKeyDel(robj *key) {
slotToKeyUpdateKey(key,0);
}
void slotToKeyFlush(void) {
raxFree(server.cluster->slots_to_keys);
server.cluster->slots_to_keys = raxNew();
memset(server.cluster->slots_keys_count,0,
sizeof(server.cluster->slots_keys_count));
}
/* Pupulate the specified array of objects with keys in the specified slot.
* New objects are returned to represent keys, it's up to the caller to
* decrement the reference count to release the keys names. */
unsigned int getKeysInSlot(unsigned int hashslot, robj **keys, unsigned int count) {
raxIterator iter;
int j = 0;
unsigned char indexed[2];
indexed[0] = (hashslot >> 8) & 0xff;
indexed[1] = hashslot & 0xff;
raxStart(&iter,server.cluster->slots_to_keys);
raxSeek(&iter,">=",indexed,2);
while(count-- && raxNext(&iter)) {
if (iter.key[0] != indexed[0] || iter.key[1] != indexed[1]) break;
keys[j++] = createStringObject((char*)iter.key+2,iter.key_len-2);
}
raxStop(&iter);
return j;
}
/* Remove all the keys in the specified hash slot.
* The number of removed items is returned. */
unsigned int delKeysInSlot(unsigned int hashslot) {
raxIterator iter;
int j = 0;
unsigned char indexed[2];
indexed[0] = (hashslot >> 8) & 0xff;
indexed[1] = hashslot & 0xff;
raxStart(&iter,server.cluster->slots_to_keys);
while(server.cluster->slots_keys_count[hashslot]) {
raxSeek(&iter,">=",indexed,2);
raxNext(&iter);
robj *key = createStringObject((char*)iter.key+2,iter.key_len-2);
dbDelete(&server.db[0],key);
decrRefCount(key);
j++;
}
raxStop(&iter);
return j;
}
unsigned int countKeysInSlot(unsigned int hashslot) {
return server.cluster->slots_keys_count[hashslot];
}
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