src/rdb.c

   1 #include "redis.h"
   2 #include "lzf.h"    /* LZF compression library */
   3 #include "zipmap.h"
   4 #include "endianconv.h"
   5
   6 #include <math.h>
   7 #include <sys/types.h>
   8 #include <sys/time.h>
   9 #include <sys/resource.h>
  10 #include <sys/wait.h>
  11 #include <arpa/inet.h>
  12 #include <sys/stat.h>
  13
  14 static int rdbWriteRaw(rio *rdb, void *p, size_t len) {
  15     if (rdb && rioWrite(rdb,p,len) == 0)
  16         return -1;
  17     return len;
  18 }
  19
  20 int rdbSaveType(rio *rdb, unsigned char type) {
  21     return rdbWriteRaw(rdb,&type,1);
  22 }
  23
  24 /* Load a "type" in RDB format, that is a one byte unsigned integer.
  25  * This function is not only used to load object types, but also special
  26  * "types" like the end-of-file type, the EXPIRE type, and so forth. */
  27 int rdbLoadType(rio *rdb) {
  28     unsigned char type;
  29     if (rioRead(rdb,&type,1) == 0) return -1;
  30     return type;
  31 }
  32
  33 time_t rdbLoadTime(rio *rdb) {
  34     int32_t t32;
  35     if (rioRead(rdb,&t32,4) == 0) return -1;
  36     return (time_t)t32;
  37 }
  38
  39 int rdbSaveMillisecondTime(rio *rdb, long long t) {
  40     int64_t t64 = (int64_t) t;
  41     return rdbWriteRaw(rdb,&t64,8);
  42 }
  43
  44 long long rdbLoadMillisecondTime(rio *rdb) {
  45     int64_t t64;
  46     if (rioRead(rdb,&t64,8) == 0) return -1;
  47     return (long long)t64;
  48 }
  49
  50 /* Saves an encoded length. The first two bits in the first byte are used to
  51  * hold the encoding type. See the REDIS_RDB_* definitions for more information
  52  * on the types of encoding. */
  53 int rdbSaveLen(rio *rdb, uint32_t len) {
  54     unsigned char buf[2];
  55     size_t nwritten;
  56
  57     if (len < (1<<6)) {
  58         /* Save a 6 bit len */
  59         buf[0] = (len&0xFF)|(REDIS_RDB_6BITLEN<<6);
  60         if (rdbWriteRaw(rdb,buf,1) == -1) return -1;
  61         nwritten = 1;
  62     } else if (len < (1<<14)) {
  63         /* Save a 14 bit len */
  64         buf[0] = ((len>>8)&0xFF)|(REDIS_RDB_14BITLEN<<6);
  65         buf[1] = len&0xFF;
  66         if (rdbWriteRaw(rdb,buf,2) == -1) return -1;
  67         nwritten = 2;
  68     } else {
  69         /* Save a 32 bit len */
  70         buf[0] = (REDIS_RDB_32BITLEN<<6);
  71         if (rdbWriteRaw(rdb,buf,1) == -1) return -1;
  72         len = htonl(len);
  73         if (rdbWriteRaw(rdb,&len,4) == -4) return -1;
  74         nwritten = 1+4;
  75     }
  76     return nwritten;
  77 }
  78
  79 /* Load an encoded length. The "isencoded" argument is set to 1 if the length
  80  * is not actually a length but an "encoding type". See the REDIS_RDB_ENC_*
  81  * definitions in rdb.h for more information. */
  82 uint32_t rdbLoadLen(rio *rdb, int *isencoded) {
  83     unsigned char buf[2];
  84     uint32_t len;
  85     int type;
  86
  87     if (isencoded) *isencoded = 0;
  88     if (rioRead(rdb,buf,1) == 0) return REDIS_RDB_LENERR;
  89     type = (buf[0]&0xC0)>>6;
  90     if (type == REDIS_RDB_ENCVAL) {
  91         /* Read a 6 bit encoding type. */
  92         if (isencoded) *isencoded = 1;
  93         return buf[0]&0x3F;
  94     } else if (type == REDIS_RDB_6BITLEN) {
  95         /* Read a 6 bit len. */
  96         return buf[0]&0x3F;
  97     } else if (type == REDIS_RDB_14BITLEN) {
  98         /* Read a 14 bit len. */
  99         if (rioRead(rdb,buf+1,1) == 0) return REDIS_RDB_LENERR;
 100         return ((buf[0]&0x3F)<<8)|buf[1];
 101     } else {
 102         /* Read a 32 bit len. */
 103         if (rioRead(rdb,&len,4) == 0) return REDIS_RDB_LENERR;
 104         return ntohl(len);
 105     }
 106 }
 107
 108 /* Encodes the "value" argument as integer when it fits in the supported ranges
 109  * for encoded types. If the function successfully encodes the integer, the
 110  * representation is stored in the buffer pointer to by "enc" and the string
 111  * length is returned. Otherwise 0 is returned. */
 112 int rdbEncodeInteger(long long value, unsigned char *enc) {
 113     if (value >= -(1<<7) && value <= (1<<7)-1) {
 114         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT8;
 115         enc[1] = value&0xFF;
 116         return 2;
 117     } else if (value >= -(1<<15) && value <= (1<<15)-1) {
 118         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT16;
 119         enc[1] = value&0xFF;
 120         enc[2] = (value>>8)&0xFF;
 121         return 3;
 122     } else if (value >= -((long long)1<<31) && value <= ((long long)1<<31)-1) {
 123         enc[0] = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_INT32;
 124         enc[1] = value&0xFF;
 125         enc[2] = (value>>8)&0xFF;
 126         enc[3] = (value>>16)&0xFF;
 127         enc[4] = (value>>24)&0xFF;
 128         return 5;
 129     } else {
 130         return 0;
 131     }
 132 }
 133
 134 /* Loads an integer-encoded object with the specified encoding type "enctype".
 135  * If the "encode" argument is set the function may return an integer-encoded
 136  * string object, otherwise it always returns a raw string object. */
 137 robj *rdbLoadIntegerObject(rio *rdb, int enctype, int encode) {
 138     unsigned char enc[4];
 139     long long val;
 140
 141     if (enctype == REDIS_RDB_ENC_INT8) {
 142         if (rioRead(rdb,enc,1) == 0) return NULL;
 143         val = (signed char)enc[0];
 144     } else if (enctype == REDIS_RDB_ENC_INT16) {
 145         uint16_t v;
 146         if (rioRead(rdb,enc,2) == 0) return NULL;
 147         v = enc[0]|(enc[1]<<8);
 148         val = (int16_t)v;
 149     } else if (enctype == REDIS_RDB_ENC_INT32) {
 150         uint32_t v;
 151         if (rioRead(rdb,enc,4) == 0) return NULL;
 152         v = enc[0]|(enc[1]<<8)|(enc[2]<<16)|(enc[3]<<24);
 153         val = (int32_t)v;
 154     } else {
 155         val = 0; /* anti-warning */
 156         redisPanic("Unknown RDB integer encoding type");
 157     }
 158     if (encode)
 159         return createStringObjectFromLongLong(val);
 160     else
 161         return createObject(REDIS_STRING,sdsfromlonglong(val));
 162 }
 163
 164 /* String objects in the form "2391" "-100" without any space and with a
 165  * range of values that can fit in an 8, 16 or 32 bit signed value can be
 166  * encoded as integers to save space */
 167 int rdbTryIntegerEncoding(char *s, size_t len, unsigned char *enc) {
 168     long long value;
 169     char *endptr, buf[32];
 170
 171     /* Check if it's possible to encode this value as a number */
 172     value = strtoll(s, &endptr, 10);
 173     if (endptr[0] != '\0') return 0;
 174     ll2string(buf,32,value);
 175
 176     /* If the number converted back into a string is not identical
 177      * then it's not possible to encode the string as integer */
 178     if (strlen(buf) != len || memcmp(buf,s,len)) return 0;
 179
 180     return rdbEncodeInteger(value,enc);
 181 }
 182
 183 int rdbSaveLzfStringObject(rio *rdb, unsigned char *s, size_t len) {
 184     size_t comprlen, outlen;
 185     unsigned char byte;
 186     int n, nwritten = 0;
 187     void *out;
 188
 189     /* We require at least four bytes compression for this to be worth it */
 190     if (len <= 4) return 0;
 191     outlen = len-4;
 192     if ((out = zmalloc(outlen+1)) == NULL) return 0;
 193     comprlen = lzf_compress(s, len, out, outlen);
 194     if (comprlen == 0) {
 195         zfree(out);
 196         return 0;
 197     }
 198     /* Data compressed! Let's save it on disk */
 199     byte = (REDIS_RDB_ENCVAL<<6)|REDIS_RDB_ENC_LZF;
 200     if ((n = rdbWriteRaw(rdb,&byte,1)) == -1) goto writeerr;
 201     nwritten += n;
 202
 203     if ((n = rdbSaveLen(rdb,comprlen)) == -1) goto writeerr;
 204     nwritten += n;
 205
 206     if ((n = rdbSaveLen(rdb,len)) == -1) goto writeerr;
 207     nwritten += n;
 208
 209     if ((n = rdbWriteRaw(rdb,out,comprlen)) == -1) goto writeerr;
 210     nwritten += n;
 211
 212     zfree(out);
 213     return nwritten;
 214
 215 writeerr:
 216     zfree(out);
 217     return -1;
 218 }
 219
 220 robj *rdbLoadLzfStringObject(rio *rdb) {
 221     unsigned int len, clen;
 222     unsigned char *c = NULL;
 223     sds val = NULL;
 224
 225     if ((clen = rdbLoadLen(rdb,NULL)) == REDIS_RDB_LENERR) return NULL;
 226     if ((len = rdbLoadLen(rdb,NULL)) == REDIS_RDB_LENERR) return NULL;
 227     if ((c = zmalloc(clen)) == NULL) goto err;
 228     if ((val = sdsnewlen(NULL,len)) == NULL) goto err;
 229     if (rioRead(rdb,c,clen) == 0) goto err;
 230     if (lzf_decompress(c,clen,val,len) == 0) goto err;
 231     zfree(c);
 232     return createObject(REDIS_STRING,val);
 233 err:
 234     zfree(c);
 235     sdsfree(val);
 236     return NULL;
 237 }
 238
 239 /* Save a string objet as [len][data] on disk. If the object is a string
 240  * representation of an integer value we try to save it in a special form */
 241 int rdbSaveRawString(rio *rdb, unsigned char *s, size_t len) {
 242     int enclen;
 243     int n, nwritten = 0;
 244
 245     /* Try integer encoding */
 246     if (len <= 11) {
 247         unsigned char buf[5];
 248         if ((enclen = rdbTryIntegerEncoding((char*)s,len,buf)) > 0) {
 249             if (rdbWriteRaw(rdb,buf,enclen) == -1) return -1;
 250             return enclen;
 251         }
 252     }
 253
 254     /* Try LZF compression - under 20 bytes it's unable to compress even
 255      * aaaaaaaaaaaaaaaaaa so skip it */
 256     if (server.rdb_compression && len > 20) {
 257         n = rdbSaveLzfStringObject(rdb,s,len);
 258         if (n == -1) return -1;
 259         if (n > 0) return n;
 260         /* Return value of 0 means data can't be compressed, save the old way */
 261     }
 262
 263     /* Store verbatim */
 264     if ((n = rdbSaveLen(rdb,len)) == -1) return -1;
 265     nwritten += n;
 266     if (len > 0) {
 267         if (rdbWriteRaw(rdb,s,len) == -1) return -1;
 268         nwritten += len;
 269     }
 270     return nwritten;
 271 }
 272
 273 /* Save a long long value as either an encoded string or a string. */
 274 int rdbSaveLongLongAsStringObject(rio *rdb, long long value) {
 275     unsigned char buf[32];
 276     int n, nwritten = 0;
 277     int enclen = rdbEncodeInteger(value,buf);
 278     if (enclen > 0) {
 279         return rdbWriteRaw(rdb,buf,enclen);
 280     } else {
 281         /* Encode as string */
 282         enclen = ll2string((char*)buf,32,value);
 283         redisAssert(enclen < 32);
 284         if ((n = rdbSaveLen(rdb,enclen)) == -1) return -1;
 285         nwritten += n;
 286         if ((n = rdbWriteRaw(rdb,buf,enclen)) == -1) return -1;
 287         nwritten += n;
 288     }
 289     return nwritten;
 290 }
 291
 292 /* Like rdbSaveStringObjectRaw() but handle encoded objects */
 293 int rdbSaveStringObject(rio *rdb, robj *obj) {
 294     /* Avoid to decode the object, then encode it again, if the
 295      * object is alrady integer encoded. */
 296     if (obj->encoding == REDIS_ENCODING_INT) {
 297         return rdbSaveLongLongAsStringObject(rdb,(long)obj->ptr);
 298     } else {
 299         redisAssertWithInfo(NULL,obj,obj->encoding == REDIS_ENCODING_RAW);
 300         return rdbSaveRawString(rdb,obj->ptr,sdslen(obj->ptr));
 301     }
 302 }
 303
 304 robj *rdbGenericLoadStringObject(rio *rdb, int encode) {
 305     int isencoded;
 306     uint32_t len;
 307     sds val;
 308
 309     len = rdbLoadLen(rdb,&isencoded);
 310     if (isencoded) {
 311         switch(len) {
 312         case REDIS_RDB_ENC_INT8:
 313         case REDIS_RDB_ENC_INT16:
 314         case REDIS_RDB_ENC_INT32:
 315             return rdbLoadIntegerObject(rdb,len,encode);
 316         case REDIS_RDB_ENC_LZF:
 317             return rdbLoadLzfStringObject(rdb);
 318         default:
 319             redisPanic("Unknown RDB encoding type");
 320         }
 321     }
 322
 323     if (len == REDIS_RDB_LENERR) return NULL;
 324     val = sdsnewlen(NULL,len);
 325     if (len && rioRead(rdb,val,len) == 0) {
 326         sdsfree(val);
 327         return NULL;
 328     }
 329     return createObject(REDIS_STRING,val);
 330 }
 331
 332 robj *rdbLoadStringObject(rio *rdb) {
 333     return rdbGenericLoadStringObject(rdb,0);
 334 }
 335
 336 robj *rdbLoadEncodedStringObject(rio *rdb) {
 337     return rdbGenericLoadStringObject(rdb,1);
 338 }
 339
 340 /* Save a double value. Doubles are saved as strings prefixed by an unsigned
 341  * 8 bit integer specifing the length of the representation.
 342  * This 8 bit integer has special values in order to specify the following
 343  * conditions:
 344  * 253: not a number
 345  * 254: + inf
 346  * 255: - inf
 347  */
 348 int rdbSaveDoubleValue(rio *rdb, double val) {
 349     unsigned char buf[128];
 350     int len;
 351
 352     if (isnan(val)) {
 353         buf[0] = 253;
 354         len = 1;
 355     } else if (!isfinite(val)) {
 356         len = 1;
 357         buf[0] = (val < 0) ? 255 : 254;
 358     } else {
 359 #if (DBL_MANT_DIG >= 52) && (LLONG_MAX == 0x7fffffffffffffffLL)
 360         /* Check if the float is in a safe range to be casted into a
 361          * long long. We are assuming that long long is 64 bit here.
 362          * Also we are assuming that there are no implementations around where
 363          * double has precision < 52 bit.
 364          *
 365          * Under this assumptions we test if a double is inside an interval
 366          * where casting to long long is safe. Then using two castings we
 367          * make sure the decimal part is zero. If all this is true we use
 368          * integer printing function that is much faster. */
 369         double min = -4503599627370495; /* (2^52)-1 */
 370         double max = 4503599627370496; /* -(2^52) */
 371         if (val > min && val < max && val == ((double)((long long)val)))
 372             ll2string((char*)buf+1,sizeof(buf),(long long)val);
 373         else
 374 #endif
 375             snprintf((char*)buf+1,sizeof(buf)-1,"%.17g",val);
 376         buf[0] = strlen((char*)buf+1);
 377         len = buf[0]+1;
 378     }
 379     return rdbWriteRaw(rdb,buf,len);
 380 }
 381
 382 /* For information about double serialization check rdbSaveDoubleValue() */
 383 int rdbLoadDoubleValue(rio *rdb, double *val) {
 384     char buf[128];
 385     unsigned char len;
 386
 387     if (rioRead(rdb,&len,1) == 0) return -1;
 388     switch(len) {
 389     case 255: *val = R_NegInf; return 0;
 390     case 254: *val = R_PosInf; return 0;
 391     case 253: *val = R_Nan; return 0;
 392     default:
 393         if (rioRead(rdb,buf,len) == 0) return -1;
 394         buf[len] = '\0';
 395         sscanf(buf, "%lg", val);
 396         return 0;
 397     }
 398 }
 399
 400 /* Save the object type of object "o". */
 401 int rdbSaveObjectType(rio *rdb, robj *o) {
 402     switch (o->type) {
 403     case REDIS_STRING:
 404         return rdbSaveType(rdb,REDIS_RDB_TYPE_STRING);
 405     case REDIS_LIST:
 406         if (o->encoding == REDIS_ENCODING_ZIPLIST)
 407             return rdbSaveType(rdb,REDIS_RDB_TYPE_LIST_ZIPLIST);
 408         else if (o->encoding == REDIS_ENCODING_LINKEDLIST)
 409             return rdbSaveType(rdb,REDIS_RDB_TYPE_LIST);
 410         else
 411             redisPanic("Unknown list encoding");
 412     case REDIS_SET:
 413         if (o->encoding == REDIS_ENCODING_INTSET)
 414             return rdbSaveType(rdb,REDIS_RDB_TYPE_SET_INTSET);
 415         else if (o->encoding == REDIS_ENCODING_HT)
 416             return rdbSaveType(rdb,REDIS_RDB_TYPE_SET);
 417         else
 418             redisPanic("Unknown set encoding");
 419     case REDIS_ZSET:
 420         if (o->encoding == REDIS_ENCODING_ZIPLIST)
 421             return rdbSaveType(rdb,REDIS_RDB_TYPE_ZSET_ZIPLIST);
 422         else if (o->encoding == REDIS_ENCODING_SKIPLIST)
 423             return rdbSaveType(rdb,REDIS_RDB_TYPE_ZSET);
 424         else
 425             redisPanic("Unknown sorted set encoding");
 426     case REDIS_HASH:
 427         if (o->encoding == REDIS_ENCODING_ZIPLIST)
 428             return rdbSaveType(rdb,REDIS_RDB_TYPE_HASH_ZIPLIST);
 429         else if (o->encoding == REDIS_ENCODING_HT)
 430             return rdbSaveType(rdb,REDIS_RDB_TYPE_HASH);
 431         else
 432             redisPanic("Unknown hash encoding");
 433     default:
 434         redisPanic("Unknown object type");
 435     }
 436     return -1; /* avoid warning */
 437 }
 438
 439 /* Use rdbLoadType() to load a TYPE in RDB format, but returns -1 if the
 440  * type is not specifically a valid Object Type. */
 441 int rdbLoadObjectType(rio *rdb) {
 442     int type;
 443     if ((type = rdbLoadType(rdb)) == -1) return -1;
 444     if (!rdbIsObjectType(type)) return -1;
 445     return type;
 446 }
 447
 448 /* Save a Redis object. Returns -1 on error, 0 on success. */
 449 int rdbSaveObject(rio *rdb, robj *o) {
 450     int n, nwritten = 0;
 451
 452     if (o->type == REDIS_STRING) {
 453         /* Save a string value */
 454         if ((n = rdbSaveStringObject(rdb,o)) == -1) return -1;
 455         nwritten += n;
 456     } else if (o->type == REDIS_LIST) {
 457         /* Save a list value */
 458         if (o->encoding == REDIS_ENCODING_ZIPLIST) {
 459             size_t l = ziplistBlobLen((unsigned char*)o->ptr);
 460
 461             if ((n = rdbSaveRawString(rdb,o->ptr,l)) == -1) return -1;
 462             nwritten += n;
 463         } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) {
 464             list *list = o->ptr;
 465             listIter li;
 466             listNode *ln;
 467
 468             if ((n = rdbSaveLen(rdb,listLength(list))) == -1) return -1;
 469             nwritten += n;
 470
 471             listRewind(list,&li);
 472             while((ln = listNext(&li))) {
 473                 robj *eleobj = listNodeValue(ln);
 474                 if ((n = rdbSaveStringObject(rdb,eleobj)) == -1) return -1;
 475                 nwritten += n;
 476             }
 477         } else {
 478             redisPanic("Unknown list encoding");
 479         }
 480     } else if (o->type == REDIS_SET) {
 481         /* Save a set value */
 482         if (o->encoding == REDIS_ENCODING_HT) {
 483             dict *set = o->ptr;
 484             dictIterator *di = dictGetIterator(set);
 485             dictEntry *de;
 486
 487             if ((n = rdbSaveLen(rdb,dictSize(set))) == -1) return -1;
 488             nwritten += n;
 489
 490             while((de = dictNext(di)) != NULL) {
 491                 robj *eleobj = dictGetKey(de);
 492                 if ((n = rdbSaveStringObject(rdb,eleobj)) == -1) return -1;
 493                 nwritten += n;
 494             }
 495             dictReleaseIterator(di);
 496         } else if (o->encoding == REDIS_ENCODING_INTSET) {
 497             size_t l = intsetBlobLen((intset*)o->ptr);
 498
 499             if ((n = rdbSaveRawString(rdb,o->ptr,l)) == -1) return -1;
 500             nwritten += n;
 501         } else {
 502             redisPanic("Unknown set encoding");
 503         }
 504     } else if (o->type == REDIS_ZSET) {
 505         /* Save a sorted set value */
 506         if (o->encoding == REDIS_ENCODING_ZIPLIST) {
 507             size_t l = ziplistBlobLen((unsigned char*)o->ptr);
 508
 509             if ((n = rdbSaveRawString(rdb,o->ptr,l)) == -1) return -1;
 510             nwritten += n;
 511         } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
 512             zset *zs = o->ptr;
 513             dictIterator *di = dictGetIterator(zs->dict);
 514             dictEntry *de;
 515
 516             if ((n = rdbSaveLen(rdb,dictSize(zs->dict))) == -1) return -1;
 517             nwritten += n;
 518
 519             while((de = dictNext(di)) != NULL) {
 520                 robj *eleobj = dictGetKey(de);
 521                 double *score = dictGetVal(de);
 522
 523                 if ((n = rdbSaveStringObject(rdb,eleobj)) == -1) return -1;
 524                 nwritten += n;
 525                 if ((n = rdbSaveDoubleValue(rdb,*score)) == -1) return -1;
 526                 nwritten += n;
 527             }
 528             dictReleaseIterator(di);
 529         } else {
 530             redisPanic("Unknown sorted set encoding");
 531         }
 532     } else if (o->type == REDIS_HASH) {
 533         /* Save a hash value */
 534         if (o->encoding == REDIS_ENCODING_ZIPLIST) {
 535             size_t l = ziplistBlobLen((unsigned char*)o->ptr);
 536
 537             if ((n = rdbSaveRawString(rdb,o->ptr,l)) == -1) return -1;
 538             nwritten += n;
 539
 540         } else if (o->encoding == REDIS_ENCODING_HT) {
 541             dictIterator *di = dictGetIterator(o->ptr);
 542             dictEntry *de;
 543
 544             if ((n = rdbSaveLen(rdb,dictSize((dict*)o->ptr))) == -1) return -1;
 545             nwritten += n;
 546
 547             while((de = dictNext(di)) != NULL) {
 548                 robj *key = dictGetKey(de);
 549                 robj *val = dictGetVal(de);
 550
 551                 if ((n = rdbSaveStringObject(rdb,key)) == -1) return -1;
 552                 nwritten += n;
 553                 if ((n = rdbSaveStringObject(rdb,val)) == -1) return -1;
 554                 nwritten += n;
 555             }
 556             dictReleaseIterator(di);
 557
 558         } else {
 559             redisPanic("Unknown hash encoding");
 560         }
 561
 562     } else {
 563         redisPanic("Unknown object type");
 564     }
 565     return nwritten;
 566 }
 567
 568 /* Return the length the object will have on disk if saved with
 569  * the rdbSaveObject() function. Currently we use a trick to get
 570  * this length with very little changes to the code. In the future
 571  * we could switch to a faster solution. */
 572 off_t rdbSavedObjectLen(robj *o) {
 573     int len = rdbSaveObject(NULL,o);
 574     redisAssertWithInfo(NULL,o,len != -1);
 575     return len;
 576 }
 577
 578 /* Save a key-value pair, with expire time, type, key, value.
 579  * On error -1 is returned.
 580  * On success if the key was actaully saved 1 is returned, otherwise 0
 581  * is returned (the key was already expired). */
 582 int rdbSaveKeyValuePair(rio *rdb, robj *key, robj *val,
 583                         long long expiretime, long long now)
 584 {
 585     /* Save the expire time */
 586     if (expiretime != -1) {
 587         /* If this key is already expired skip it */
 588         if (expiretime < now) return 0;
 589         if (rdbSaveType(rdb,REDIS_RDB_OPCODE_EXPIRETIME_MS) == -1) return -1;
 590         if (rdbSaveMillisecondTime(rdb,expiretime) == -1) return -1;
 591     }
 592
 593     /* Save type, key, value */
 594     if (rdbSaveObjectType(rdb,val) == -1) return -1;
 595     if (rdbSaveStringObject(rdb,key) == -1) return -1;
 596     if (rdbSaveObject(rdb,val) == -1) return -1;
 597     return 1;
 598 }
 599
 600 /* Save the DB on disk. Return REDIS_ERR on error, REDIS_OK on success */
 601 int rdbSave(char *filename) {
 602     dictIterator *di = NULL;
 603     dictEntry *de;
 604     char tmpfile[256];
 605     char magic[10];
 606     int j;
 607     long long now = mstime();
 608     FILE *fp;
 609     rio rdb;
 610     uint64_t cksum;
 611
 612     snprintf(tmpfile,256,"temp-%d.rdb", (int) getpid());
 613     fp = fopen(tmpfile,"w");
 614     if (!fp) {
 615         redisLog(REDIS_WARNING, "Failed opening .rdb for saving: %s",
 616             strerror(errno));
 617         return REDIS_ERR;
 618     }
 619
 620     rioInitWithFile(&rdb,fp);
 621     if (server.rdb_checksum)
 622         rdb.update_cksum = rioGenericUpdateChecksum;
 623     snprintf(magic,sizeof(magic),"REDIS%04d",REDIS_RDB_VERSION);
 624     if (rdbWriteRaw(&rdb,magic,9) == -1) goto werr;
 625
 626     for (j = 0; j < server.dbnum; j++) {
 627         redisDb *db = server.db+j;
 628         dict *d = db->dict;
 629         if (dictSize(d) == 0) continue;
 630         di = dictGetSafeIterator(d);
 631         if (!di) {
 632             fclose(fp);
 633             return REDIS_ERR;
 634         }
 635
 636         /* Write the SELECT DB opcode */
 637         if (rdbSaveType(&rdb,REDIS_RDB_OPCODE_SELECTDB) == -1) goto werr;
 638         if (rdbSaveLen(&rdb,j) == -1) goto werr;
 639
 640         /* Iterate this DB writing every entry */
 641         while((de = dictNext(di)) != NULL) {
 642             sds keystr = dictGetKey(de);
 643             robj key, *o = dictGetVal(de);
 644             long long expire;
 645
 646             initStaticStringObject(key,keystr);
 647             expire = getExpire(db,&key);
 648             if (rdbSaveKeyValuePair(&rdb,&key,o,expire,now) == -1) goto werr;
 649         }
 650         dictReleaseIterator(di);
 651     }
 652     di = NULL; /* So that we don't release it again on error. */
 653
 654     /* EOF opcode */
 655     if (rdbSaveType(&rdb,REDIS_RDB_OPCODE_EOF) == -1) goto werr;
 656
 657     /* CRC64 checksum. It will be zero if checksum computation is disabled, the
 658      * loading code skips the check in this case. */
 659     cksum = rdb.cksum;
 660     memrev64ifbe(&cksum);
 661     rioWrite(&rdb,&cksum,8);
 662
 663     /* Make sure data will not remain on the OS's output buffers */
 664     fflush(fp);
 665     fsync(fileno(fp));
 666     fclose(fp);
 667
 668     /* Use RENAME to make sure the DB file is changed atomically only
 669      * if the generate DB file is ok. */
 670     if (rename(tmpfile,filename) == -1) {
 671         redisLog(REDIS_WARNING,"Error moving temp DB file on the final destination: %s", strerror(errno));
 672         unlink(tmpfile);
 673         return REDIS_ERR;
 674     }
 675     redisLog(REDIS_NOTICE,"DB saved on disk");
 676     server.dirty = 0;
 677     server.lastsave = time(NULL);
 678     server.lastbgsave_status = REDIS_OK;
 679     return REDIS_OK;
 680
 681 werr:
 682     fclose(fp);
 683     unlink(tmpfile);
 684     redisLog(REDIS_WARNING,"Write error saving DB on disk: %s", strerror(errno));
 685     if (di) dictReleaseIterator(di);
 686     return REDIS_ERR;
 687 }
 688
 689 int rdbSaveBackground(char *filename) {
 690     pid_t childpid;
 691     long long start;
 692
 693     if (server.rdb_child_pid != -1) return REDIS_ERR;
 694
 695     server.dirty_before_bgsave = server.dirty;
 696
 697     start = ustime();
 698     if ((childpid = fork()) == 0) {
 699         int retval;
 700
 701         /* Child */
 702         if (server.ipfd > 0) close(server.ipfd);
 703         if (server.sofd > 0) close(server.sofd);
 704         retval = rdbSave(filename);
 705         exitFromChild((retval == REDIS_OK) ? 0 : 1);
 706     } else {
 707         /* Parent */
 708         server.stat_fork_time = ustime()-start;
 709         if (childpid == -1) {
 710             redisLog(REDIS_WARNING,"Can't save in background: fork: %s",
 711                 strerror(errno));
 712             return REDIS_ERR;
 713         }
 714         redisLog(REDIS_NOTICE,"Background saving started by pid %d",childpid);
 715         server.rdb_save_time_start = time(NULL);
 716         server.rdb_child_pid = childpid;
 717         updateDictResizePolicy();
 718         return REDIS_OK;
 719     }
 720     return REDIS_OK; /* unreached */
 721 }
 722
 723 void rdbRemoveTempFile(pid_t childpid) {
 724     char tmpfile[256];
 725
 726     snprintf(tmpfile,256,"temp-%d.rdb", (int) childpid);
 727     unlink(tmpfile);
 728 }
 729
 730 /* Load a Redis object of the specified type from the specified file.
 731  * On success a newly allocated object is returned, otherwise NULL. */
 732 robj *rdbLoadObject(int rdbtype, rio *rdb) {
 733     robj *o, *ele, *dec;
 734     size_t len;
 735     unsigned int i;
 736
 737     redisLog(REDIS_DEBUG,"LOADING OBJECT %d (at %d)\n",rdbtype,rioTell(rdb));
 738     if (rdbtype == REDIS_RDB_TYPE_STRING) {
 739         /* Read string value */
 740         if ((o = rdbLoadEncodedStringObject(rdb)) == NULL) return NULL;
 741         o = tryObjectEncoding(o);
 742     } else if (rdbtype == REDIS_RDB_TYPE_LIST) {
 743         /* Read list value */
 744         if ((len = rdbLoadLen(rdb,NULL)) == REDIS_RDB_LENERR) return NULL;
 745
 746         /* Use a real list when there are too many entries */
 747         if (len > server.list_max_ziplist_entries) {
 748             o = createListObject();
 749         } else {
 750             o = createZiplistObject();
 751         }
 752
 753         /* Load every single element of the list */
 754         while(len--) {
 755             if ((ele = rdbLoadEncodedStringObject(rdb)) == NULL) return NULL;
 756
 757             /* If we are using a ziplist and the value is too big, convert
 758              * the object to a real list. */
 759             if (o->encoding == REDIS_ENCODING_ZIPLIST &&
 760                 ele->encoding == REDIS_ENCODING_RAW &&
 761                 sdslen(ele->ptr) > server.list_max_ziplist_value)
 762                     listTypeConvert(o,REDIS_ENCODING_LINKEDLIST);
 763
 764             if (o->encoding == REDIS_ENCODING_ZIPLIST) {
 765                 dec = getDecodedObject(ele);
 766                 o->ptr = ziplistPush(o->ptr,dec->ptr,sdslen(dec->ptr),REDIS_TAIL);
 767                 decrRefCount(dec);
 768                 decrRefCount(ele);
 769             } else {
 770                 ele = tryObjectEncoding(ele);
 771                 listAddNodeTail(o->ptr,ele);
 772             }
 773         }
 774     } else if (rdbtype == REDIS_RDB_TYPE_SET) {
 775         /* Read list/set value */
 776         if ((len = rdbLoadLen(rdb,NULL)) == REDIS_RDB_LENERR) return NULL;
 777
 778         /* Use a regular set when there are too many entries. */
 779         if (len > server.set_max_intset_entries) {
 780             o = createSetObject();
 781             /* It's faster to expand the dict to the right size asap in order
 782              * to avoid rehashing */
 783             if (len > DICT_HT_INITIAL_SIZE)
 784                 dictExpand(o->ptr,len);
 785         } else {
 786             o = createIntsetObject();
 787         }
 788
 789         /* Load every single element of the list/set */
 790         for (i = 0; i < len; i++) {
 791             long long llval;
 792             if ((ele = rdbLoadEncodedStringObject(rdb)) == NULL) return NULL;
 793             ele = tryObjectEncoding(ele);
 794
 795             if (o->encoding == REDIS_ENCODING_INTSET) {
 796                 /* Fetch integer value from element */
 797                 if (isObjectRepresentableAsLongLong(ele,&llval) == REDIS_OK) {
 798                     o->ptr = intsetAdd(o->ptr,llval,NULL);
 799                 } else {
 800                     setTypeConvert(o,REDIS_ENCODING_HT);
 801                     dictExpand(o->ptr,len);
 802                 }
 803             }
 804
 805             /* This will also be called when the set was just converted
 806              * to regular hash table encoded set */
 807             if (o->encoding == REDIS_ENCODING_HT) {
 808                 dictAdd((dict*)o->ptr,ele,NULL);
 809             } else {
 810                 decrRefCount(ele);
 811             }
 812         }
 813     } else if (rdbtype == REDIS_RDB_TYPE_ZSET) {
 814         /* Read list/set value */
 815         size_t zsetlen;
 816         size_t maxelelen = 0;
 817         zset *zs;
 818
 819         if ((zsetlen = rdbLoadLen(rdb,NULL)) == REDIS_RDB_LENERR) return NULL;
 820         o = createZsetObject();
 821         zs = o->ptr;
 822
 823         /* Load every single element of the list/set */
 824         while(zsetlen--) {
 825             robj *ele;
 826             double score;
 827             zskiplistNode *znode;
 828
 829             if ((ele = rdbLoadEncodedStringObject(rdb)) == NULL) return NULL;
 830             ele = tryObjectEncoding(ele);
 831             if (rdbLoadDoubleValue(rdb,&score) == -1) return NULL;
 832
 833             /* Don't care about integer-encoded strings. */
 834             if (ele->encoding == REDIS_ENCODING_RAW &&
 835                 sdslen(ele->ptr) > maxelelen)
 836                     maxelelen = sdslen(ele->ptr);
 837
 838             znode = zslInsert(zs->zsl,score,ele);
 839             dictAdd(zs->dict,ele,&znode->score);
 840             incrRefCount(ele); /* added to skiplist */
 841         }
 842
 843         /* Convert *after* loading, since sorted sets are not stored ordered. */
 844         if (zsetLength(o) <= server.zset_max_ziplist_entries &&
 845             maxelelen <= server.zset_max_ziplist_value)
 846                 zsetConvert(o,REDIS_ENCODING_ZIPLIST);
 847     } else if (rdbtype == REDIS_RDB_TYPE_HASH) {
 848         size_t len;
 849         int ret;
 850
 851         len = rdbLoadLen(rdb, NULL);
 852         if (len == REDIS_RDB_LENERR) return NULL;
 853
 854         o = createHashObject();
 855
 856         /* Too many entries? Use an hash table. */
 857         if (len > server.hash_max_ziplist_entries)
 858             hashTypeConvert(o, REDIS_ENCODING_HT);
 859
 860         /* Load every field and value into the ziplist */
 861         while (o->encoding == REDIS_ENCODING_ZIPLIST && len > 0) {
 862             robj *field, *value;
 863
 864             len--;
 865             /* Load raw strings */
 866             field = rdbLoadStringObject(rdb);
 867             if (field == NULL) return NULL;
 868             redisAssert(field->encoding == REDIS_ENCODING_RAW);
 869             value = rdbLoadStringObject(rdb);
 870             if (value == NULL) return NULL;
 871             redisAssert(field->encoding == REDIS_ENCODING_RAW);
 872
 873             /* Add pair to ziplist */
 874             o->ptr = ziplistPush(o->ptr, field->ptr, sdslen(field->ptr), ZIPLIST_TAIL);
 875             o->ptr = ziplistPush(o->ptr, value->ptr, sdslen(value->ptr), ZIPLIST_TAIL);
 876             /* Convert to hash table if size threshold is exceeded */
 877             if (sdslen(field->ptr) > server.hash_max_ziplist_value ||
 878                 sdslen(value->ptr) > server.hash_max_ziplist_value)
 879             {
 880                 decrRefCount(field);
 881                 decrRefCount(value);
 882                 hashTypeConvert(o, REDIS_ENCODING_HT);
 883                 break;
 884             }
 885             decrRefCount(field);
 886             decrRefCount(value);
 887         }
 888
 889         /* Load remaining fields and values into the hash table */
 890         while (o->encoding == REDIS_ENCODING_HT && len > 0) {
 891             robj *field, *value;
 892
 893             len--;
 894             /* Load encoded strings */
 895             field = rdbLoadEncodedStringObject(rdb);
 896             if (field == NULL) return NULL;
 897             value = rdbLoadEncodedStringObject(rdb);
 898             if (value == NULL) return NULL;
 899
 900             field = tryObjectEncoding(field);
 901             value = tryObjectEncoding(value);
 902
 903             /* Add pair to hash table */
 904             ret = dictAdd((dict*)o->ptr, field, value);
 905             redisAssert(ret == REDIS_OK);
 906         }
 907
 908         /* All pairs should be read by now */
 909         redisAssert(len == 0);
 910
 911     } else if (rdbtype == REDIS_RDB_TYPE_HASH_ZIPMAP  ||
 912                rdbtype == REDIS_RDB_TYPE_LIST_ZIPLIST ||
 913                rdbtype == REDIS_RDB_TYPE_SET_INTSET   ||
 914                rdbtype == REDIS_RDB_TYPE_ZSET_ZIPLIST ||
 915                rdbtype == REDIS_RDB_TYPE_HASH_ZIPLIST)
 916     {
 917         robj *aux = rdbLoadStringObject(rdb);
 918
 919         if (aux == NULL) return NULL;
 920         o = createObject(REDIS_STRING,NULL); /* string is just placeholder */
 921         o->ptr = zmalloc(sdslen(aux->ptr));
 922         memcpy(o->ptr,aux->ptr,sdslen(aux->ptr));
 923         decrRefCount(aux);
 924
 925         /* Fix the object encoding, and make sure to convert the encoded
 926          * data type into the base type if accordingly to the current
 927          * configuration there are too many elements in the encoded data
 928          * type. Note that we only check the length and not max element
 929          * size as this is an O(N) scan. Eventually everything will get
 930          * converted. */
 931         switch(rdbtype) {
 932             case REDIS_RDB_TYPE_HASH_ZIPMAP:
 933                 /* Convert to ziplist encoded hash. This must be deprecated
 934                  * when loading dumps created by Redis 2.4 gets deprecated. */
 935                 {
 936                     unsigned char *zl = ziplistNew();
 937                     unsigned char *zi = zipmapRewind(o->ptr);
 938                     unsigned char *fstr, *vstr;
 939                     unsigned int flen, vlen;
 940                     unsigned int maxlen = 0;
 941
 942                     while ((zi = zipmapNext(zi, &fstr, &flen, &vstr, &vlen)) != NULL) {
 943                         if (flen > maxlen) maxlen = flen;
 944                         if (vlen > maxlen) maxlen = vlen;
 945                         zl = ziplistPush(zl, fstr, flen, ZIPLIST_TAIL);
 946                         zl = ziplistPush(zl, vstr, vlen, ZIPLIST_TAIL);
 947                     }
 948
 949                     zfree(o->ptr);
 950                     o->ptr = zl;
 951                     o->type = REDIS_HASH;
 952                     o->encoding = REDIS_ENCODING_ZIPLIST;
 953
 954                     if (hashTypeLength(o) > server.hash_max_ziplist_entries ||
 955                         maxlen > server.hash_max_ziplist_value)
 956                     {
 957                         hashTypeConvert(o, REDIS_ENCODING_HT);
 958                     }
 959                 }
 960                 break;
 961             case REDIS_RDB_TYPE_LIST_ZIPLIST:
 962                 o->type = REDIS_LIST;
 963                 o->encoding = REDIS_ENCODING_ZIPLIST;
 964                 if (ziplistLen(o->ptr) > server.list_max_ziplist_entries)
 965                     listTypeConvert(o,REDIS_ENCODING_LINKEDLIST);
 966                 break;
 967             case REDIS_RDB_TYPE_SET_INTSET:
 968                 o->type = REDIS_SET;
 969                 o->encoding = REDIS_ENCODING_INTSET;
 970                 if (intsetLen(o->ptr) > server.set_max_intset_entries)
 971                     setTypeConvert(o,REDIS_ENCODING_HT);
 972                 break;
 973             case REDIS_RDB_TYPE_ZSET_ZIPLIST:
 974                 o->type = REDIS_ZSET;
 975                 o->encoding = REDIS_ENCODING_ZIPLIST;
 976                 if (zsetLength(o) > server.zset_max_ziplist_entries)
 977                     zsetConvert(o,REDIS_ENCODING_SKIPLIST);
 978                 break;
 979             case REDIS_RDB_TYPE_HASH_ZIPLIST:
 980                 o->type = REDIS_HASH;
 981                 o->encoding = REDIS_ENCODING_ZIPLIST;
 982                 if (hashTypeLength(o) > server.hash_max_ziplist_entries)
 983                     hashTypeConvert(o, REDIS_ENCODING_HT);
 984                 break;
 985             default:
 986                 redisPanic("Unknown encoding");
 987                 break;
 988         }
 989     } else {
 990         redisPanic("Unknown object type");
 991     }
 992     return o;
 993 }
 994
 995 /* Mark that we are loading in the global state and setup the fields
 996  * needed to provide loading stats. */
 997 void startLoading(FILE *fp) {
 998     struct stat sb;
 999
1000     /* Load the DB */
1001     server.loading = 1;
1002     server.loading_start_time = time(NULL);
1003     if (fstat(fileno(fp), &sb) == -1) {
1004         server.loading_total_bytes = 1; /* just to avoid division by zero */
1005     } else {
1006         server.loading_total_bytes = sb.st_size;
1007     }
1008 }
1009
1010 /* Refresh the loading progress info */
1011 void loadingProgress(off_t pos) {
1012     server.loading_loaded_bytes = pos;
1013 }
1014
1015 /* Loading finished */
1016 void stopLoading(void) {
1017     server.loading = 0;
1018 }
1019
1020 int rdbLoad(char *filename) {
1021     uint32_t dbid;
1022     int type, rdbver;
1023     redisDb *db = server.db+0;
1024     char buf[1024];
1025     long long expiretime, now = mstime();
1026     long loops = 0;
1027     FILE *fp;
1028     rio rdb;
1029
1030     fp = fopen(filename,"r");
1031     if (!fp) {
1032         errno = ENOENT;
1033         return REDIS_ERR;
1034     }
1035     rioInitWithFile(&rdb,fp);
1036     if (server.rdb_checksum)
1037         rdb.update_cksum = rioGenericUpdateChecksum;
1038     if (rioRead(&rdb,buf,9) == 0) goto eoferr;
1039     buf[9] = '\0';
1040     if (memcmp(buf,"REDIS",5) != 0) {
1041         fclose(fp);
1042         redisLog(REDIS_WARNING,"Wrong signature trying to load DB from file");
1043         errno = EINVAL;
1044         return REDIS_ERR;
1045     }
1046     rdbver = atoi(buf+5);
1047     if (rdbver < 1 || rdbver > REDIS_RDB_VERSION) {
1048         fclose(fp);
1049         redisLog(REDIS_WARNING,"Can't handle RDB format version %d",rdbver);
1050         errno = EINVAL;
1051         return REDIS_ERR;
1052     }
1053
1054     startLoading(fp);
1055     while(1) {
1056         robj *key, *val;
1057         expiretime = -1;
1058
1059         /* Serve the clients from time to time */
1060         if (!(loops++ % 1000)) {
1061             loadingProgress(rioTell(&rdb));
1062             aeProcessEvents(server.el, AE_FILE_EVENTS|AE_DONT_WAIT);
1063         }
1064
1065         /* Read type. */
1066         if ((type = rdbLoadType(&rdb)) == -1) goto eoferr;
1067         if (type == REDIS_RDB_OPCODE_EXPIRETIME) {
1068             if ((expiretime = rdbLoadTime(&rdb)) == -1) goto eoferr;
1069             /* We read the time so we need to read the object type again. */
1070             if ((type = rdbLoadType(&rdb)) == -1) goto eoferr;
1071             /* the EXPIRETIME opcode specifies time in seconds, so convert
1072              * into milliesconds. */
1073             expiretime *= 1000;
1074         } else if (type == REDIS_RDB_OPCODE_EXPIRETIME_MS) {
1075             /* Milliseconds precision expire times introduced with RDB
1076              * version 3. */
1077             if ((expiretime = rdbLoadMillisecondTime(&rdb)) == -1) goto eoferr;
1078             /* We read the time so we need to read the object type again. */
1079             if ((type = rdbLoadType(&rdb)) == -1) goto eoferr;
1080         }
1081
1082         if (type == REDIS_RDB_OPCODE_EOF)
1083             break;
1084
1085         /* Handle SELECT DB opcode as a special case */
1086         if (type == REDIS_RDB_OPCODE_SELECTDB) {
1087             if ((dbid = rdbLoadLen(&rdb,NULL)) == REDIS_RDB_LENERR)
1088                 goto eoferr;
1089             if (dbid >= (unsigned)server.dbnum) {
1090                 redisLog(REDIS_WARNING,"FATAL: Data file was created with a Redis server configured to handle more than %d databases. Exiting\n", server.dbnum);
1091                 exit(1);
1092             }
1093             db = server.db+dbid;
1094             continue;
1095         }
1096         /* Read key */
1097         if ((key = rdbLoadStringObject(&rdb)) == NULL) goto eoferr;
1098         /* Read value */
1099         if ((val = rdbLoadObject(type,&rdb)) == NULL) goto eoferr;
1100         /* Check if the key already expired. This function is used when loading
1101          * an RDB file from disk, either at startup, or when an RDB was
1102          * received from the master. In the latter case, the master is
1103          * responsible for key expiry. If we would expire keys here, the
1104          * snapshot taken by the master may not be reflected on the slave. */
1105         if (server.masterhost == NULL && expiretime != -1 && expiretime < now) {
1106             decrRefCount(key);
1107             decrRefCount(val);
1108             continue;
1109         }
1110         /* Add the new object in the hash table */
1111         dbAdd(db,key,val);
1112
1113         /* Set the expire time if needed */
1114         if (expiretime != -1) setExpire(db,key,expiretime);
1115
1116         decrRefCount(key);
1117     }
1118     /* Verify the checksum if RDB version is >= 5 */
1119     if (rdbver >= 5 && server.rdb_checksum) {
1120         uint64_t cksum, expected = rdb.cksum;
1121
1122         if (rioRead(&rdb,&cksum,8) == 0) goto eoferr;
1123         memrev64ifbe(&cksum);
1124         if (cksum == 0) {
1125             redisLog(REDIS_WARNING,"RDB file was saved with checksum disabled: no check performed.");
1126         } else if (cksum != expected) {
1127             redisLog(REDIS_WARNING,"Wrong RDB checksum. Aborting now.");
1128             exit(1);
1129         }
1130     }
1131
1132     fclose(fp);
1133     stopLoading();
1134     return REDIS_OK;
1135
1136 eoferr: /* unexpected end of file is handled here with a fatal exit */
1137     redisLog(REDIS_WARNING,"Short read or OOM loading DB. Unrecoverable error, aborting now.");
1138     exit(1);
1139     return REDIS_ERR; /* Just to avoid warning */
1140 }
1141
1142 /* A background saving child (BGSAVE) terminated its work. Handle this. */
1143 void backgroundSaveDoneHandler(int exitcode, int bysignal) {
1144     if (!bysignal && exitcode == 0) {
1145         redisLog(REDIS_NOTICE,
1146             "Background saving terminated with success");
1147         server.dirty = server.dirty - server.dirty_before_bgsave;
1148         server.lastsave = time(NULL);
1149         server.lastbgsave_status = REDIS_OK;
1150     } else if (!bysignal && exitcode != 0) {
1151         redisLog(REDIS_WARNING, "Background saving error");
1152         server.lastbgsave_status = REDIS_ERR;
1153     } else {
1154         redisLog(REDIS_WARNING,
1155             "Background saving terminated by signal %d", bysignal);
1156         rdbRemoveTempFile(server.rdb_child_pid);
1157         server.lastbgsave_status = REDIS_ERR;
1158     }
1159     server.rdb_child_pid = -1;
1160     server.rdb_save_time_last = time(NULL)-server.rdb_save_time_start;
1161     server.rdb_save_time_start = -1;
1162     /* Possibly there are slaves waiting for a BGSAVE in order to be served
1163      * (the first stage of SYNC is a bulk transfer of dump.rdb) */
1164     updateSlavesWaitingBgsave(exitcode == 0 ? REDIS_OK : REDIS_ERR);
1165 }
1166
1167 void saveCommand(redisClient *c) {
1168     if (server.rdb_child_pid != -1) {
1169         addReplyError(c,"Background save already in progress");
1170         return;
1171     }
1172     if (rdbSave(server.rdb_filename) == REDIS_OK) {
1173         addReply(c,shared.ok);
1174     } else {
1175         addReply(c,shared.err);
1176     }
1177 }
1178
1179 void bgsaveCommand(redisClient *c) {
1180     if (server.rdb_child_pid != -1) {
1181         addReplyError(c,"Background save already in progress");
1182     } else if (server.aof_child_pid != -1) {
1183         addReplyError(c,"Can't BGSAVE while AOF log rewriting is in progress");
1184     } else if (rdbSaveBackground(server.rdb_filename) == REDIS_OK) {
1185         addReplyStatus(c,"Background saving started");
1186     } else {
1187         addReply(c,shared.err);
1188     }
1189 }