src/debug.c

   1 #include "redis.h"
   2 #include "sha1.h"   /* SHA1 is used for DEBUG DIGEST */
   3
   4 #include <arpa/inet.h>
   5 #include <signal.h>
   6
   7 #ifdef HAVE_BACKTRACE
   8 #include <execinfo.h>
   9 #include <ucontext.h>
  10 #endif /* HAVE_BACKTRACE */
  11
  12 /* ================================= Debugging ============================== */
  13
  14 /* Compute the sha1 of string at 's' with 'len' bytes long.
  15  * The SHA1 is then xored againt the string pointed by digest.
  16  * Since xor is commutative, this operation is used in order to
  17  * "add" digests relative to unordered elements.
  18  *
  19  * So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
  20 void xorDigest(unsigned char *digest, void *ptr, size_t len) {
  21     SHA1_CTX ctx;
  22     unsigned char hash[20], *s = ptr;
  23     int j;
  24
  25     SHA1Init(&ctx);
  26     SHA1Update(&ctx,s,len);
  27     SHA1Final(hash,&ctx);
  28
  29     for (j = 0; j < 20; j++)
  30         digest[j] ^= hash[j];
  31 }
  32
  33 void xorObjectDigest(unsigned char *digest, robj *o) {
  34     o = getDecodedObject(o);
  35     xorDigest(digest,o->ptr,sdslen(o->ptr));
  36     decrRefCount(o);
  37 }
  38
  39 /* This function instead of just computing the SHA1 and xoring it
  40  * against diget, also perform the digest of "digest" itself and
  41  * replace the old value with the new one.
  42  *
  43  * So the final digest will be:
  44  *
  45  * digest = SHA1(digest xor SHA1(data))
  46  *
  47  * This function is used every time we want to preserve the order so
  48  * that digest(a,b,c,d) will be different than digest(b,c,d,a)
  49  *
  50  * Also note that mixdigest("foo") followed by mixdigest("bar")
  51  * will lead to a different digest compared to "fo", "obar".
  52  */
  53 void mixDigest(unsigned char *digest, void *ptr, size_t len) {
  54     SHA1_CTX ctx;
  55     char *s = ptr;
  56
  57     xorDigest(digest,s,len);
  58     SHA1Init(&ctx);
  59     SHA1Update(&ctx,digest,20);
  60     SHA1Final(digest,&ctx);
  61 }
  62
  63 void mixObjectDigest(unsigned char *digest, robj *o) {
  64     o = getDecodedObject(o);
  65     mixDigest(digest,o->ptr,sdslen(o->ptr));
  66     decrRefCount(o);
  67 }
  68
  69 /* Compute the dataset digest. Since keys, sets elements, hashes elements
  70  * are not ordered, we use a trick: every aggregate digest is the xor
  71  * of the digests of their elements. This way the order will not change
  72  * the result. For list instead we use a feedback entering the output digest
  73  * as input in order to ensure that a different ordered list will result in
  74  * a different digest. */
  75 void computeDatasetDigest(unsigned char *final) {
  76     unsigned char digest[20];
  77     char buf[128];
  78     dictIterator *di = NULL;
  79     dictEntry *de;
  80     int j;
  81     uint32_t aux;
  82
  83     memset(final,0,20); /* Start with a clean result */
  84
  85     for (j = 0; j < server.dbnum; j++) {
  86         redisDb *db = server.db+j;
  87
  88         if (dictSize(db->dict) == 0) continue;
  89         di = dictGetIterator(db->dict);
  90
  91         /* hash the DB id, so the same dataset moved in a different
  92          * DB will lead to a different digest */
  93         aux = htonl(j);
  94         mixDigest(final,&aux,sizeof(aux));
  95
  96         /* Iterate this DB writing every entry */
  97         while((de = dictNext(di)) != NULL) {
  98             sds key;
  99             robj *keyobj, *o;
 100             long long expiretime;
 101
 102             memset(digest,0,20); /* This key-val digest */
 103             key = dictGetKey(de);
 104             keyobj = createStringObject(key,sdslen(key));
 105
 106             mixDigest(digest,key,sdslen(key));
 107
 108             o = dictGetVal(de);
 109
 110             aux = htonl(o->type);
 111             mixDigest(digest,&aux,sizeof(aux));
 112             expiretime = getExpire(db,keyobj);
 113
 114             /* Save the key and associated value */
 115             if (o->type == REDIS_STRING) {
 116                 mixObjectDigest(digest,o);
 117             } else if (o->type == REDIS_LIST) {
 118                 listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
 119                 listTypeEntry entry;
 120                 while(listTypeNext(li,&entry)) {
 121                     robj *eleobj = listTypeGet(&entry);
 122                     mixObjectDigest(digest,eleobj);
 123                     decrRefCount(eleobj);
 124                 }
 125                 listTypeReleaseIterator(li);
 126             } else if (o->type == REDIS_SET) {
 127                 setTypeIterator *si = setTypeInitIterator(o);
 128                 robj *ele;
 129                 while((ele = setTypeNextObject(si)) != NULL) {
 130                     xorObjectDigest(digest,ele);
 131                     decrRefCount(ele);
 132                 }
 133                 setTypeReleaseIterator(si);
 134             } else if (o->type == REDIS_ZSET) {
 135                 unsigned char eledigest[20];
 136
 137                 if (o->encoding == REDIS_ENCODING_ZIPLIST) {
 138                     unsigned char *zl = o->ptr;
 139                     unsigned char *eptr, *sptr;
 140                     unsigned char *vstr;
 141                     unsigned int vlen;
 142                     long long vll;
 143                     double score;
 144
 145                     eptr = ziplistIndex(zl,0);
 146                     redisAssert(eptr != NULL);
 147                     sptr = ziplistNext(zl,eptr);
 148                     redisAssert(sptr != NULL);
 149
 150                     while (eptr != NULL) {
 151                         redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
 152                         score = zzlGetScore(sptr);
 153
 154                         memset(eledigest,0,20);
 155                         if (vstr != NULL) {
 156                             mixDigest(eledigest,vstr,vlen);
 157                         } else {
 158                             ll2string(buf,sizeof(buf),vll);
 159                             mixDigest(eledigest,buf,strlen(buf));
 160                         }
 161
 162                         snprintf(buf,sizeof(buf),"%.17g",score);
 163                         mixDigest(eledigest,buf,strlen(buf));
 164                         xorDigest(digest,eledigest,20);
 165                         zzlNext(zl,&eptr,&sptr);
 166                     }
 167                 } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
 168                     zset *zs = o->ptr;
 169                     dictIterator *di = dictGetIterator(zs->dict);
 170                     dictEntry *de;
 171
 172                     while((de = dictNext(di)) != NULL) {
 173                         robj *eleobj = dictGetKey(de);
 174                         double *score = dictGetVal(de);
 175
 176                         snprintf(buf,sizeof(buf),"%.17g",*score);
 177                         memset(eledigest,0,20);
 178                         mixObjectDigest(eledigest,eleobj);
 179                         mixDigest(eledigest,buf,strlen(buf));
 180                         xorDigest(digest,eledigest,20);
 181                     }
 182                     dictReleaseIterator(di);
 183                 } else {
 184                     redisPanic("Unknown sorted set encoding");
 185                 }
 186             } else if (o->type == REDIS_HASH) {
 187                 hashTypeIterator *hi;
 188                 robj *obj;
 189
 190                 hi = hashTypeInitIterator(o);
 191                 while (hashTypeNext(hi) != REDIS_ERR) {
 192                     unsigned char eledigest[20];
 193
 194                     memset(eledigest,0,20);
 195                     obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
 196                     mixObjectDigest(eledigest,obj);
 197                     decrRefCount(obj);
 198                     obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
 199                     mixObjectDigest(eledigest,obj);
 200                     decrRefCount(obj);
 201                     xorDigest(digest,eledigest,20);
 202                 }
 203                 hashTypeReleaseIterator(hi);
 204             } else {
 205                 redisPanic("Unknown object type");
 206             }
 207             /* If the key has an expire, add it to the mix */
 208             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
 209             /* We can finally xor the key-val digest to the final digest */
 210             xorDigest(final,digest,20);
 211             decrRefCount(keyobj);
 212         }
 213         dictReleaseIterator(di);
 214     }
 215 }
 216
 217 void debugCommand(redisClient *c) {
 218     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
 219         *((char*)-1) = 'x';
 220     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
 221         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
 222         redisAssertWithInfo(c,c->argv[0],1 == 2);
 223     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
 224         if (rdbSave(server.rdb_filename) != REDIS_OK) {
 225             addReply(c,shared.err);
 226             return;
 227         }
 228         emptyDb();
 229         if (rdbLoad(server.rdb_filename) != REDIS_OK) {
 230             addReplyError(c,"Error trying to load the RDB dump");
 231             return;
 232         }
 233         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
 234         addReply(c,shared.ok);
 235     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
 236         emptyDb();
 237         if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
 238             addReply(c,shared.err);
 239             return;
 240         }
 241         server.dirty = 0; /* Prevent AOF / replication */
 242         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
 243         addReply(c,shared.ok);
 244     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
 245         dictEntry *de;
 246         robj *val;
 247         char *strenc;
 248
 249         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
 250             addReply(c,shared.nokeyerr);
 251             return;
 252         }
 253         val = dictGetVal(de);
 254         strenc = strEncoding(val->encoding);
 255
 256         addReplyStatusFormat(c,
 257             "Value at:%p refcount:%d "
 258             "encoding:%s serializedlength:%lld "
 259             "lru:%d lru_seconds_idle:%lu",
 260             (void*)val, val->refcount,
 261             strenc, (long long) rdbSavedObjectLen(val),
 262             val->lru, estimateObjectIdleTime(val));
 263     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
 264         long keys, j;
 265         robj *key, *val;
 266         char buf[128];
 267
 268         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
 269             return;
 270         for (j = 0; j < keys; j++) {
 271             snprintf(buf,sizeof(buf),"key:%lu",j);
 272             key = createStringObject(buf,strlen(buf));
 273             if (lookupKeyRead(c->db,key) != NULL) {
 274                 decrRefCount(key);
 275                 continue;
 276             }
 277             snprintf(buf,sizeof(buf),"value:%lu",j);
 278             val = createStringObject(buf,strlen(buf));
 279             dbAdd(c->db,key,val);
 280             decrRefCount(key);
 281         }
 282         addReply(c,shared.ok);
 283     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
 284         unsigned char digest[20];
 285         sds d = sdsempty();
 286         int j;
 287
 288         computeDatasetDigest(digest);
 289         for (j = 0; j < 20; j++)
 290             d = sdscatprintf(d, "%02x",digest[j]);
 291         addReplyStatus(c,d);
 292         sdsfree(d);
 293     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
 294         double dtime = strtod(c->argv[2]->ptr,NULL);
 295         long long utime = dtime*1000000;
 296
 297         usleep(utime);
 298         addReply(c,shared.ok);
 299     } else {
 300         addReplyError(c,
 301             "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
 302     }
 303 }
 304
 305 /* =========================== Crash handling  ============================== */
 306
 307 void _redisAssert(char *estr, char *file, int line) {
 308     bugReportStart();
 309     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
 310     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
 311 #ifdef HAVE_BACKTRACE
 312     server.assert_failed = estr;
 313     server.assert_file = file;
 314     server.assert_line = line;
 315     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
 316 #endif
 317     *((char*)-1) = 'x';
 318 }
 319
 320 void _redisAssertPrintClientInfo(redisClient *c) {
 321     int j;
 322
 323     bugReportStart();
 324     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
 325     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
 326     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
 327     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
 328     for (j=0; j < c->argc; j++) {
 329         char buf[128];
 330         char *arg;
 331
 332         if (c->argv[j]->type == REDIS_STRING &&
 333             c->argv[j]->encoding == REDIS_ENCODING_RAW)
 334         {
 335             arg = (char*) c->argv[j]->ptr;
 336         } else {
 337             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
 338                 c->argv[j]->type, c->argv[j]->encoding);
 339             arg = buf;
 340         }
 341         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
 342             j, arg, c->argv[j]->refcount);
 343     }
 344 }
 345
 346 void redisLogObjectDebugInfo(robj *o) {
 347     redisLog(REDIS_WARNING,"Object type: %d", o->type);
 348     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
 349     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
 350     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
 351         redisLog(REDIS_WARNING,"Object raw string len: %d", sdslen(o->ptr));
 352         if (sdslen(o->ptr) < 4096)
 353             redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
 354     } else if (o->type == REDIS_LIST) {
 355         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
 356     } else if (o->type == REDIS_SET) {
 357         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
 358     } else if (o->type == REDIS_HASH) {
 359         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
 360     } else if (o->type == REDIS_ZSET) {
 361         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
 362         if (o->encoding == REDIS_ENCODING_SKIPLIST)
 363             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
 364     }
 365 }
 366
 367 void _redisAssertPrintObject(robj *o) {
 368     bugReportStart();
 369     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
 370     redisLogObjectDebugInfo(o);
 371 }
 372
 373 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
 374     if (c) _redisAssertPrintClientInfo(c);
 375     if (o) _redisAssertPrintObject(o);
 376     _redisAssert(estr,file,line);
 377 }
 378
 379 void _redisPanic(char *msg, char *file, int line) {
 380     bugReportStart();
 381     redisLog(REDIS_WARNING,"------------------------------------------------");
 382     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
 383     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
 384 #ifdef HAVE_BACKTRACE
 385     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
 386 #endif
 387     redisLog(REDIS_WARNING,"------------------------------------------------");
 388     *((char*)-1) = 'x';
 389 }
 390
 391 void bugReportStart(void) {
 392     if (server.bug_report_start == 0) {
 393         redisLog(REDIS_WARNING,
 394             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
 395         server.bug_report_start = 1;
 396     }
 397 }
 398
 399 #ifdef HAVE_BACKTRACE
 400 static void *getMcontextEip(ucontext_t *uc) {
 401 #if defined(__FreeBSD__)
 402     return (void*) uc->uc_mcontext.mc_eip;
 403 #elif defined(__dietlibc__)
 404     return (void*) uc->uc_mcontext.eip;
 405 #elif defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
 406   #if __x86_64__
 407     return (void*) uc->uc_mcontext->__ss.__rip;
 408   #elif __i386__
 409     return (void*) uc->uc_mcontext->__ss.__eip;
 410   #else
 411     return (void*) uc->uc_mcontext->__ss.__srr0;
 412   #endif
 413 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
 414   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
 415     return (void*) uc->uc_mcontext->__ss.__rip;
 416   #else
 417     return (void*) uc->uc_mcontext->__ss.__eip;
 418   #endif
 419 #elif defined(__i386__)
 420     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
 421 #elif defined(__X86_64__) || defined(__x86_64__)
 422     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
 423 #elif defined(__ia64__) /* Linux IA64 */
 424     return (void*) uc->uc_mcontext.sc_ip;
 425 #else
 426     return NULL;
 427 #endif
 428 }
 429
 430 void logStackContent(void **sp) {
 431     int i;
 432     for (i = 15; i >= 0; i--) {
 433         if (sizeof(long) == 4)
 434             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", sp+i, sp[i]);
 435         else
 436             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", sp+i, sp[i]);
 437     }
 438 }
 439
 440 void logRegisters(ucontext_t *uc) {
 441     redisLog(REDIS_WARNING, "--- REGISTERS");
 442 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
 443   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
 444     redisLog(REDIS_WARNING,
 445     "\n"
 446     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
 447     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
 448     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
 449     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
 450     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
 451         uc->uc_mcontext->__ss.__rax,
 452         uc->uc_mcontext->__ss.__rbx,
 453         uc->uc_mcontext->__ss.__rcx,
 454         uc->uc_mcontext->__ss.__rdx,
 455         uc->uc_mcontext->__ss.__rdi,
 456         uc->uc_mcontext->__ss.__rsi,
 457         uc->uc_mcontext->__ss.__rbp,
 458         uc->uc_mcontext->__ss.__rsp,
 459         uc->uc_mcontext->__ss.__r8,
 460         uc->uc_mcontext->__ss.__r9,
 461         uc->uc_mcontext->__ss.__r10,
 462         uc->uc_mcontext->__ss.__r11,
 463         uc->uc_mcontext->__ss.__r12,
 464         uc->uc_mcontext->__ss.__r13,
 465         uc->uc_mcontext->__ss.__r14,
 466         uc->uc_mcontext->__ss.__r15,
 467         uc->uc_mcontext->__ss.__rip,
 468         uc->uc_mcontext->__ss.__rflags,
 469         uc->uc_mcontext->__ss.__cs,
 470         uc->uc_mcontext->__ss.__fs,
 471         uc->uc_mcontext->__ss.__gs
 472     );
 473     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
 474   #else
 475     redisLog(REDIS_WARNING,
 476     "\n"
 477     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
 478     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
 479     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
 480     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
 481         uc->uc_mcontext->__ss.__eax,
 482         uc->uc_mcontext->__ss.__ebx,
 483         uc->uc_mcontext->__ss.__ecx,
 484         uc->uc_mcontext->__ss.__edx,
 485         uc->uc_mcontext->__ss.__edi,
 486         uc->uc_mcontext->__ss.__esi,
 487         uc->uc_mcontext->__ss.__ebp,
 488         uc->uc_mcontext->__ss.__esp,
 489         uc->uc_mcontext->__ss.__ss,
 490         uc->uc_mcontext->__ss.__eflags,
 491         uc->uc_mcontext->__ss.__eip,
 492         uc->uc_mcontext->__ss.__cs,
 493         uc->uc_mcontext->__ss.__ds,
 494         uc->uc_mcontext->__ss.__es,
 495         uc->uc_mcontext->__ss.__fs,
 496         uc->uc_mcontext->__ss.__gs
 497     );
 498     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
 499   #endif
 500 #elif defined(__i386__)
 501     redisLog(REDIS_WARNING,
 502     "\n"
 503     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
 504     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
 505     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
 506     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
 507         uc->uc_mcontext.gregs[11],
 508         uc->uc_mcontext.gregs[8],
 509         uc->uc_mcontext.gregs[10],
 510         uc->uc_mcontext.gregs[9],
 511         uc->uc_mcontext.gregs[4],
 512         uc->uc_mcontext.gregs[5],
 513         uc->uc_mcontext.gregs[6],
 514         uc->uc_mcontext.gregs[7],
 515         uc->uc_mcontext.gregs[18],
 516         uc->uc_mcontext.gregs[17],
 517         uc->uc_mcontext.gregs[14],
 518         uc->uc_mcontext.gregs[15],
 519         uc->uc_mcontext.gregs[3],
 520         uc->uc_mcontext.gregs[2],
 521         uc->uc_mcontext.gregs[1],
 522         uc->uc_mcontext.gregs[0]
 523     );
 524     logStackContent((void**)uc->uc_mcontext.gregs[7]);
 525 #elif defined(__X86_64__) || defined(__x86_64__)
 526     redisLog(REDIS_WARNING,
 527     "\n"
 528     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
 529     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
 530     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
 531     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
 532     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
 533         uc->uc_mcontext.gregs[13],
 534         uc->uc_mcontext.gregs[11],
 535         uc->uc_mcontext.gregs[14],
 536         uc->uc_mcontext.gregs[12],
 537         uc->uc_mcontext.gregs[8],
 538         uc->uc_mcontext.gregs[9],
 539         uc->uc_mcontext.gregs[10],
 540         uc->uc_mcontext.gregs[15],
 541         uc->uc_mcontext.gregs[0],
 542         uc->uc_mcontext.gregs[1],
 543         uc->uc_mcontext.gregs[2],
 544         uc->uc_mcontext.gregs[3],
 545         uc->uc_mcontext.gregs[4],
 546         uc->uc_mcontext.gregs[5],
 547         uc->uc_mcontext.gregs[6],
 548         uc->uc_mcontext.gregs[7],
 549         uc->uc_mcontext.gregs[16],
 550         uc->uc_mcontext.gregs[17],
 551         uc->uc_mcontext.gregs[18]
 552     );
 553     logStackContent((void**)uc->uc_mcontext.gregs[15]);
 554 #else
 555     redisLog(REDIS_WARNING,
 556         "  Dumping of registers not supported for this OS/arch");
 557 #endif
 558 }
 559
 560 /* Logs the stack trace using the backtrace() call. */
 561 sds getStackTrace(ucontext_t *uc) {
 562     void *trace[100];
 563     int i, trace_size = 0;
 564     char **messages = NULL;
 565     sds st = sdsempty();
 566
 567     /* Generate the stack trace */
 568     trace_size = backtrace(trace, 100);
 569
 570     /* overwrite sigaction with caller's address */
 571     if (getMcontextEip(uc) != NULL) {
 572         trace[1] = getMcontextEip(uc);
 573     }
 574     messages = backtrace_symbols(trace, trace_size);
 575     for (i=1; i<trace_size; ++i) {
 576         st = sdscat(st,messages[i]);
 577         st = sdscatlen(st,"\n",1);
 578     }
 579     zlibc_free(messages);
 580     return st;
 581 }
 582
 583 /* Log information about the "current" client, that is, the client that is
 584  * currently being served by Redis. May be NULL if Redis is not serving a
 585  * client right now. */
 586 void logCurrentClient(void) {
 587     if (server.current_client == NULL) return;
 588
 589     redisClient *cc = server.current_client;
 590     sds client;
 591     int j;
 592
 593     redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
 594     client = getClientInfoString(cc);
 595     redisLog(REDIS_WARNING,"client: %s", client);
 596     sdsfree(client);
 597     for (j = 0; j < cc->argc; j++) {
 598         robj *decoded;
 599
 600         decoded = getDecodedObject(cc->argv[j]);
 601         redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
 602         decrRefCount(decoded);
 603     }
 604     /* Check if the first argument, usually a key, is found inside the
 605      * selected DB, and if so print info about the associated object. */
 606     if (cc->argc >= 1) {
 607         robj *val, *key;
 608         dictEntry *de;
 609
 610         key = getDecodedObject(cc->argv[1]);
 611         de = dictFind(cc->db->dict, key->ptr);
 612         if (de) {
 613             val = dictGetVal(de);
 614             redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
 615             redisLogObjectDebugInfo(val);
 616         }
 617         decrRefCount(key);
 618     }
 619 }
 620
 621 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
 622     ucontext_t *uc = (ucontext_t*) secret;
 623     sds infostring, clients, st;
 624     struct sigaction act;
 625     REDIS_NOTUSED(info);
 626
 627     bugReportStart();
 628     redisLog(REDIS_WARNING,
 629         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
 630     redisLog(REDIS_WARNING,
 631         "    Failed assertion: %s (%s:%d)", server.assert_failed,
 632                         server.assert_file, server.assert_line);
 633
 634     /* Log the stack trace */
 635     st = getStackTrace(uc);
 636     redisLog(REDIS_WARNING, "--- STACK TRACE\n%s", st);
 637     sdsfree(st);
 638
 639     /* Log INFO and CLIENT LIST */
 640     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
 641     infostring = genRedisInfoString("all");
 642     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
 643         dictGetHashFunctionSeed());
 644     redisLogRaw(REDIS_WARNING, infostring);
 645     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
 646     clients = getAllClientsInfoString();
 647     redisLogRaw(REDIS_WARNING, clients);
 648     sdsfree(infostring);
 649     sdsfree(clients);
 650
 651     /* Log the current client */
 652     logCurrentClient();
 653
 654     /* Log dump of processor registers */
 655     logRegisters(uc);
 656
 657     redisLog(REDIS_WARNING,
 658 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
 659 "       Please report the crash opening an issue on github:\n\n"
 660 "           http://github.com/antirez/redis/issues\n\n"
 661 "  Suspect RAM error? Use redis-server --test-memory to veryfy it.\n\n"
 662 );
 663     /* free(messages); Don't call free() with possibly corrupted memory. */
 664     if (server.daemonize) unlink(server.pidfile);
 665
 666     /* Make sure we exit with the right signal at the end. So for instance
 667      * the core will be dumped if enabled. */
 668     sigemptyset (&act.sa_mask);
 669     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
 670     act.sa_handler = SIG_DFL;
 671     sigaction (sig, &act, NULL);
 672     kill(getpid(),sig);
 673 }
 674 #endif /* HAVE_BACKTRACE */
 675
 676 /* =========================== Software Watchdog ============================ */
 677 #include <sys/time.h>
 678
 679 void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
 680     ucontext_t *uc = (ucontext_t*) secret;
 681     REDIS_NOTUSED(info);
 682     REDIS_NOTUSED(sig);
 683     sds st, log;
 684
 685     log = sdsnew("\n--- WATCHDOG TIMER EXPIRED ---\n");
 686 #ifdef HAVE_BACKTRACE
 687     st = getStackTrace(uc);
 688 #else
 689     st = sdsnew("Sorry: no support for backtrace().\n");
 690 #endif
 691     log = sdscatsds(log,st);
 692     log = sdscat(log,"------\n");
 693     redisLogFromHandler(REDIS_WARNING,log);
 694     sdsfree(st);
 695     sdsfree(log);
 696 }
 697
 698 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
 699  * If a timer is already scheduled, this function will re-schedule it to the
 700  * specified time. If period is 0 the current timer is disabled. */
 701 void watchdogScheduleSignal(int period) {
 702     struct itimerval it;
 703
 704     /* Will stop the timer if period is 0. */
 705     it.it_value.tv_sec = period/1000;
 706     it.it_value.tv_usec = (period%1000)*1000;
 707     /* Don't automatically restart. */
 708     it.it_interval.tv_sec = 0;
 709     it.it_interval.tv_usec = 0;
 710     setitimer(ITIMER_REAL, &it, NULL);
 711 }
 712
 713 /* Enable the software watchdong with the specified period in milliseconds. */
 714 void enableWatchdog(int period) {
 715     if (server.watchdog_period == 0) {
 716         struct sigaction act;
 717
 718         /* Watchdog was actually disabled, so we have to setup the signal
 719          * handler. */
 720         sigemptyset(&act.sa_mask);
 721         act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_SIGINFO;
 722         act.sa_sigaction = watchdogSignalHandler;
 723         sigaction(SIGALRM, &act, NULL);
 724     }
 725     if (period < 200) period = 200; /* We don't accept periods < 200 ms. */
 726     watchdogScheduleSignal(period); /* Adjust the current timer. */
 727     server.watchdog_period = period;
 728 }
 729
 730 /* Disable the software watchdog. */
 731 void disableWatchdog(void) {
 732     struct sigaction act;
 733     if (server.watchdog_period == 0) return; /* Already disabled. */
 734     watchdogScheduleSignal(0); /* Stop the current timer. */
 735
 736     /* Set the signal handler to SIG_IGN, this will also remove pending
 737      * signals from the queue. */
 738     sigemptyset(&act.sa_mask);
 739     act.sa_flags = 0;
 740     act.sa_handler = SIG_IGN;
 741     sigaction(SIGALRM, &act, NULL);
 742     server.watchdog_period = 0;
 743 }