src/debug.c

   1 #include "redis.h"
   2 #include "sha1.h"   /* SHA1 is used for DEBUG DIGEST */
   3
   4 #include <arpa/inet.h>
   5
   6 /* ================================= Debugging ============================== */
   7
   8 /* Compute the sha1 of string at 's' with 'len' bytes long.
   9  * The SHA1 is then xored againt the string pointed by digest.
  10  * Since xor is commutative, this operation is used in order to
  11  * "add" digests relative to unordered elements.
  12  *
  13  * So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
  14 void xorDigest(unsigned char *digest, void *ptr, size_t len) {
  15     SHA1_CTX ctx;
  16     unsigned char hash[20], *s = ptr;
  17     int j;
  18
  19     SHA1Init(&ctx);
  20     SHA1Update(&ctx,s,len);
  21     SHA1Final(hash,&ctx);
  22
  23     for (j = 0; j < 20; j++)
  24         digest[j] ^= hash[j];
  25 }
  26
  27 void xorObjectDigest(unsigned char *digest, robj *o) {
  28     o = getDecodedObject(o);
  29     xorDigest(digest,o->ptr,sdslen(o->ptr));
  30     decrRefCount(o);
  31 }
  32
  33 /* This function instead of just computing the SHA1 and xoring it
  34  * against diget, also perform the digest of "digest" itself and
  35  * replace the old value with the new one.
  36  *
  37  * So the final digest will be:
  38  *
  39  * digest = SHA1(digest xor SHA1(data))
  40  *
  41  * This function is used every time we want to preserve the order so
  42  * that digest(a,b,c,d) will be different than digest(b,c,d,a)
  43  *
  44  * Also note that mixdigest("foo") followed by mixdigest("bar")
  45  * will lead to a different digest compared to "fo", "obar".
  46  */
  47 void mixDigest(unsigned char *digest, void *ptr, size_t len) {
  48     SHA1_CTX ctx;
  49     char *s = ptr;
  50
  51     xorDigest(digest,s,len);
  52     SHA1Init(&ctx);
  53     SHA1Update(&ctx,digest,20);
  54     SHA1Final(digest,&ctx);
  55 }
  56
  57 void mixObjectDigest(unsigned char *digest, robj *o) {
  58     o = getDecodedObject(o);
  59     mixDigest(digest,o->ptr,sdslen(o->ptr));
  60     decrRefCount(o);
  61 }
  62
  63 /* Compute the dataset digest. Since keys, sets elements, hashes elements
  64  * are not ordered, we use a trick: every aggregate digest is the xor
  65  * of the digests of their elements. This way the order will not change
  66  * the result. For list instead we use a feedback entering the output digest
  67  * as input in order to ensure that a different ordered list will result in
  68  * a different digest. */
  69 void computeDatasetDigest(unsigned char *final) {
  70     unsigned char digest[20];
  71     char buf[128];
  72     dictIterator *di = NULL;
  73     dictEntry *de;
  74     int j;
  75     uint32_t aux;
  76
  77     memset(final,0,20); /* Start with a clean result */
  78
  79     for (j = 0; j < server.dbnum; j++) {
  80         redisDb *db = server.db+j;
  81
  82         if (dictSize(db->dict) == 0) continue;
  83         di = dictGetIterator(db->dict);
  84
  85         /* hash the DB id, so the same dataset moved in a different
  86          * DB will lead to a different digest */
  87         aux = htonl(j);
  88         mixDigest(final,&aux,sizeof(aux));
  89
  90         /* Iterate this DB writing every entry */
  91         while((de = dictNext(di)) != NULL) {
  92             sds key;
  93             robj *keyobj, *o;
  94             time_t expiretime;
  95
  96             memset(digest,0,20); /* This key-val digest */
  97             key = dictGetEntryKey(de);
  98             keyobj = createStringObject(key,sdslen(key));
  99
 100             mixDigest(digest,key,sdslen(key));
 101
 102             /* Make sure the key is loaded if VM is active */
 103             o = lookupKeyRead(db,keyobj);
 104
 105             aux = htonl(o->type);
 106             mixDigest(digest,&aux,sizeof(aux));
 107             expiretime = getExpire(db,keyobj);
 108
 109             /* Save the key and associated value */
 110             if (o->type == REDIS_STRING) {
 111                 mixObjectDigest(digest,o);
 112             } else if (o->type == REDIS_LIST) {
 113                 listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
 114                 listTypeEntry entry;
 115                 while(listTypeNext(li,&entry)) {
 116                     robj *eleobj = listTypeGet(&entry);
 117                     mixObjectDigest(digest,eleobj);
 118                     decrRefCount(eleobj);
 119                 }
 120                 listTypeReleaseIterator(li);
 121             } else if (o->type == REDIS_SET) {
 122                 dict *set = o->ptr;
 123                 dictIterator *di = dictGetIterator(set);
 124                 dictEntry *de;
 125
 126                 while((de = dictNext(di)) != NULL) {
 127                     robj *eleobj = dictGetEntryKey(de);
 128
 129                     xorObjectDigest(digest,eleobj);
 130                 }
 131                 dictReleaseIterator(di);
 132             } else if (o->type == REDIS_ZSET) {
 133                 zset *zs = o->ptr;
 134                 dictIterator *di = dictGetIterator(zs->dict);
 135                 dictEntry *de;
 136
 137                 while((de = dictNext(di)) != NULL) {
 138                     robj *eleobj = dictGetEntryKey(de);
 139                     double *score = dictGetEntryVal(de);
 140                     unsigned char eledigest[20];
 141
 142                     snprintf(buf,sizeof(buf),"%.17g",*score);
 143                     memset(eledigest,0,20);
 144                     mixObjectDigest(eledigest,eleobj);
 145                     mixDigest(eledigest,buf,strlen(buf));
 146                     xorDigest(digest,eledigest,20);
 147                 }
 148                 dictReleaseIterator(di);
 149             } else if (o->type == REDIS_HASH) {
 150                 hashTypeIterator *hi;
 151                 robj *obj;
 152
 153                 hi = hashTypeInitIterator(o);
 154                 while (hashTypeNext(hi) != REDIS_ERR) {
 155                     unsigned char eledigest[20];
 156
 157                     memset(eledigest,0,20);
 158                     obj = hashTypeCurrent(hi,REDIS_HASH_KEY);
 159                     mixObjectDigest(eledigest,obj);
 160                     decrRefCount(obj);
 161                     obj = hashTypeCurrent(hi,REDIS_HASH_VALUE);
 162                     mixObjectDigest(eledigest,obj);
 163                     decrRefCount(obj);
 164                     xorDigest(digest,eledigest,20);
 165                 }
 166                 hashTypeReleaseIterator(hi);
 167             } else {
 168                 redisPanic("Unknown object type");
 169             }
 170             /* If the key has an expire, add it to the mix */
 171             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
 172             /* We can finally xor the key-val digest to the final digest */
 173             xorDigest(final,digest,20);
 174             decrRefCount(keyobj);
 175         }
 176         dictReleaseIterator(di);
 177     }
 178 }
 179
 180 void debugCommand(redisClient *c) {
 181     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
 182         *((char*)-1) = 'x';
 183     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
 184         if (rdbSave(server.dbfilename) != REDIS_OK) {
 185             addReply(c,shared.err);
 186             return;
 187         }
 188         emptyDb();
 189         if (rdbLoad(server.dbfilename) != REDIS_OK) {
 190             addReply(c,shared.err);
 191             return;
 192         }
 193         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
 194         addReply(c,shared.ok);
 195     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
 196         emptyDb();
 197         if (loadAppendOnlyFile(server.appendfilename) != REDIS_OK) {
 198             addReply(c,shared.err);
 199             return;
 200         }
 201         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
 202         addReply(c,shared.ok);
 203     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
 204         dictEntry *de = dictFind(c->db->dict,c->argv[2]->ptr);
 205         robj *val;
 206
 207         if (!de) {
 208             addReply(c,shared.nokeyerr);
 209             return;
 210         }
 211         val = dictGetEntryVal(de);
 212         if (!server.vm_enabled || (val->storage == REDIS_VM_MEMORY ||
 213                                    val->storage == REDIS_VM_SWAPPING)) {
 214             char *strenc;
 215
 216             strenc = strEncoding(val->encoding);
 217             addReplySds(c,sdscatprintf(sdsempty(),
 218                 "+Value at:%p refcount:%d "
 219                 "encoding:%s serializedlength:%lld\r\n",
 220                 (void*)val, val->refcount,
 221                 strenc, (long long) rdbSavedObjectLen(val,NULL)));
 222         } else {
 223             vmpointer *vp = (vmpointer*) val;
 224             addReplySds(c,sdscatprintf(sdsempty(),
 225                 "+Value swapped at: page %llu "
 226                 "using %llu pages\r\n",
 227                 (unsigned long long) vp->page,
 228                 (unsigned long long) vp->usedpages));
 229         }
 230     } else if (!strcasecmp(c->argv[1]->ptr,"swapin") && c->argc == 3) {
 231         lookupKeyRead(c->db,c->argv[2]);
 232         addReply(c,shared.ok);
 233     } else if (!strcasecmp(c->argv[1]->ptr,"swapout") && c->argc == 3) {
 234         dictEntry *de = dictFind(c->db->dict,c->argv[2]->ptr);
 235         robj *val;
 236         vmpointer *vp;
 237
 238         if (!server.vm_enabled) {
 239             addReplySds(c,sdsnew("-ERR Virtual Memory is disabled\r\n"));
 240             return;
 241         }
 242         if (!de) {
 243             addReply(c,shared.nokeyerr);
 244             return;
 245         }
 246         val = dictGetEntryVal(de);
 247         /* Swap it */
 248         if (val->storage != REDIS_VM_MEMORY) {
 249             addReplySds(c,sdsnew("-ERR This key is not in memory\r\n"));
 250         } else if (val->refcount != 1) {
 251             addReplySds(c,sdsnew("-ERR Object is shared\r\n"));
 252         } else if ((vp = vmSwapObjectBlocking(val)) != NULL) {
 253             dictGetEntryVal(de) = vp;
 254             addReply(c,shared.ok);
 255         } else {
 256             addReply(c,shared.err);
 257         }
 258     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
 259         long keys, j;
 260         robj *key, *val;
 261         char buf[128];
 262
 263         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
 264             return;
 265         for (j = 0; j < keys; j++) {
 266             snprintf(buf,sizeof(buf),"key:%lu",j);
 267             key = createStringObject(buf,strlen(buf));
 268             if (lookupKeyRead(c->db,key) != NULL) {
 269                 decrRefCount(key);
 270                 continue;
 271             }
 272             snprintf(buf,sizeof(buf),"value:%lu",j);
 273             val = createStringObject(buf,strlen(buf));
 274             dbAdd(c->db,key,val);
 275             decrRefCount(key);
 276         }
 277         addReply(c,shared.ok);
 278     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
 279         unsigned char digest[20];
 280         sds d = sdsnew("+");
 281         int j;
 282
 283         computeDatasetDigest(digest);
 284         for (j = 0; j < 20; j++)
 285             d = sdscatprintf(d, "%02x",digest[j]);
 286
 287         d = sdscatlen(d,"\r\n",2);
 288         addReplySds(c,d);
 289     } else {
 290         addReplySds(c,sdsnew(
 291             "-ERR Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]\r\n"));
 292     }
 293 }
 294
 295 void _redisAssert(char *estr, char *file, int line) {
 296     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
 297     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
 298 #ifdef HAVE_BACKTRACE
 299     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
 300     *((char*)-1) = 'x';
 301 #endif
 302 }
 303
 304 void _redisPanic(char *msg, char *file, int line) {
 305     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
 306     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
 307 #ifdef HAVE_BACKTRACE
 308     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
 309     *((char*)-1) = 'x';
 310 #endif
 311 }