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             /* Make sure the key is loaded if VM is active */
 109             o = dictGetVal(de);
 110
 111             aux = htonl(o->type);
 112             mixDigest(digest,&aux,sizeof(aux));
 113             expiretime = getExpire(db,keyobj);
 114
 115             /* Save the key and associated value */
 116             if (o->type == REDIS_STRING) {
 117                 mixObjectDigest(digest,o);
 118             } else if (o->type == REDIS_LIST) {
 119                 listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
 120                 listTypeEntry entry;
 121                 while(listTypeNext(li,&entry)) {
 122                     robj *eleobj = listTypeGet(&entry);
 123                     mixObjectDigest(digest,eleobj);
 124                     decrRefCount(eleobj);
 125                 }
 126                 listTypeReleaseIterator(li);
 127             } else if (o->type == REDIS_SET) {
 128                 setTypeIterator *si = setTypeInitIterator(o);
 129                 robj *ele;
 130                 while((ele = setTypeNextObject(si)) != NULL) {
 131                     xorObjectDigest(digest,ele);
 132                     decrRefCount(ele);
 133                 }
 134                 setTypeReleaseIterator(si);
 135             } else if (o->type == REDIS_ZSET) {
 136                 unsigned char eledigest[20];
 137
 138                 if (o->encoding == REDIS_ENCODING_ZIPLIST) {
 139                     unsigned char *zl = o->ptr;
 140                     unsigned char *eptr, *sptr;
 141                     unsigned char *vstr;
 142                     unsigned int vlen;
 143                     long long vll;
 144                     double score;
 145
 146                     eptr = ziplistIndex(zl,0);
 147                     redisAssert(eptr != NULL);
 148                     sptr = ziplistNext(zl,eptr);
 149                     redisAssert(sptr != NULL);
 150
 151                     while (eptr != NULL) {
 152                         redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
 153                         score = zzlGetScore(sptr);
 154
 155                         memset(eledigest,0,20);
 156                         if (vstr != NULL) {
 157                             mixDigest(eledigest,vstr,vlen);
 158                         } else {
 159                             ll2string(buf,sizeof(buf),vll);
 160                             mixDigest(eledigest,buf,strlen(buf));
 161                         }
 162
 163                         snprintf(buf,sizeof(buf),"%.17g",score);
 164                         mixDigest(eledigest,buf,strlen(buf));
 165                         xorDigest(digest,eledigest,20);
 166                         zzlNext(zl,&eptr,&sptr);
 167                     }
 168                 } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
 169                     zset *zs = o->ptr;
 170                     dictIterator *di = dictGetIterator(zs->dict);
 171                     dictEntry *de;
 172
 173                     while((de = dictNext(di)) != NULL) {
 174                         robj *eleobj = dictGetKey(de);
 175                         double *score = dictGetVal(de);
 176
 177                         snprintf(buf,sizeof(buf),"%.17g",*score);
 178                         memset(eledigest,0,20);
 179                         mixObjectDigest(eledigest,eleobj);
 180                         mixDigest(eledigest,buf,strlen(buf));
 181                         xorDigest(digest,eledigest,20);
 182                     }
 183                     dictReleaseIterator(di);
 184                 } else {
 185                     redisPanic("Unknown sorted set encoding");
 186                 }
 187             } else if (o->type == REDIS_HASH) {
 188                 hashTypeIterator *hi;
 189                 robj *obj;
 190
 191                 hi = hashTypeInitIterator(o);
 192                 while (hashTypeNext(hi) != REDIS_ERR) {
 193                     unsigned char eledigest[20];
 194
 195                     memset(eledigest,0,20);
 196                     obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
 197                     mixObjectDigest(eledigest,obj);
 198                     decrRefCount(obj);
 199                     obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
 200                     mixObjectDigest(eledigest,obj);
 201                     decrRefCount(obj);
 202                     xorDigest(digest,eledigest,20);
 203                 }
 204                 hashTypeReleaseIterator(hi);
 205             } else {
 206                 redisPanic("Unknown object type");
 207             }
 208             /* If the key has an expire, add it to the mix */
 209             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
 210             /* We can finally xor the key-val digest to the final digest */
 211             xorDigest(final,digest,20);
 212             decrRefCount(keyobj);
 213         }
 214         dictReleaseIterator(di);
 215     }
 216 }
 217
 218 void debugCommand(redisClient *c) {
 219     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
 220         *((char*)-1) = 'x';
 221     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
 222         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
 223         redisAssertWithInfo(c,c->argv[0],1 == 2);
 224     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
 225         if (rdbSave(server.rdb_filename) != REDIS_OK) {
 226             addReply(c,shared.err);
 227             return;
 228         }
 229         emptyDb();
 230         if (rdbLoad(server.rdb_filename) != REDIS_OK) {
 231             addReplyError(c,"Error trying to load the RDB dump");
 232             return;
 233         }
 234         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
 235         addReply(c,shared.ok);
 236     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
 237         emptyDb();
 238         if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
 239             addReply(c,shared.err);
 240             return;
 241         }
 242         server.dirty = 0; /* Prevent AOF / replication */
 243         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
 244         addReply(c,shared.ok);
 245     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
 246         dictEntry *de;
 247         robj *val;
 248         char *strenc;
 249
 250         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
 251             addReply(c,shared.nokeyerr);
 252             return;
 253         }
 254         val = dictGetVal(de);
 255         strenc = strEncoding(val->encoding);
 256
 257         addReplyStatusFormat(c,
 258             "Value at:%p refcount:%d "
 259             "encoding:%s serializedlength:%lld "
 260             "lru:%d lru_seconds_idle:%lu",
 261             (void*)val, val->refcount,
 262             strenc, (long long) rdbSavedObjectLen(val),
 263             val->lru, estimateObjectIdleTime(val));
 264     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
 265         long keys, j;
 266         robj *key, *val;
 267         char buf[128];
 268
 269         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
 270             return;
 271         for (j = 0; j < keys; j++) {
 272             snprintf(buf,sizeof(buf),"key:%lu",j);
 273             key = createStringObject(buf,strlen(buf));
 274             if (lookupKeyRead(c->db,key) != NULL) {
 275                 decrRefCount(key);
 276                 continue;
 277             }
 278             snprintf(buf,sizeof(buf),"value:%lu",j);
 279             val = createStringObject(buf,strlen(buf));
 280             dbAdd(c->db,key,val);
 281             decrRefCount(key);
 282         }
 283         addReply(c,shared.ok);
 284     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
 285         unsigned char digest[20];
 286         sds d = sdsempty();
 287         int j;
 288
 289         computeDatasetDigest(digest);
 290         for (j = 0; j < 20; j++)
 291             d = sdscatprintf(d, "%02x",digest[j]);
 292         addReplyStatus(c,d);
 293         sdsfree(d);
 294     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
 295         double dtime = strtod(c->argv[2]->ptr,NULL);
 296         long long utime = dtime*1000000;
 297
 298         usleep(utime);
 299         addReply(c,shared.ok);
 300     } else {
 301         addReplyError(c,
 302             "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
 303     }
 304 }
 305
 306 /* =========================== Crash handling  ============================== */
 307
 308 void _redisAssert(char *estr, char *file, int line) {
 309     bugReportStart();
 310     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
 311     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
 312 #ifdef HAVE_BACKTRACE
 313     server.assert_failed = estr;
 314     server.assert_file = file;
 315     server.assert_line = line;
 316     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
 317 #endif
 318     *((char*)-1) = 'x';
 319 }
 320
 321 void _redisAssertPrintClientInfo(redisClient *c) {
 322     int j;
 323
 324     bugReportStart();
 325     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
 326     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
 327     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
 328     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
 329     for (j=0; j < c->argc; j++) {
 330         char buf[128];
 331         char *arg;
 332
 333         if (c->argv[j]->type == REDIS_STRING &&
 334             c->argv[j]->encoding == REDIS_ENCODING_RAW)
 335         {
 336             arg = (char*) c->argv[j]->ptr;
 337         } else {
 338             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
 339                 c->argv[j]->type, c->argv[j]->encoding);
 340             arg = buf;
 341         }
 342         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
 343             j, arg, c->argv[j]->refcount);
 344     }
 345 }
 346
 347 void redisLogObjectDebugInfo(robj *o) {
 348     redisLog(REDIS_WARNING,"Object type: %d", o->type);
 349     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
 350     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
 351     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
 352         redisLog(REDIS_WARNING,"Object raw string len: %d", sdslen(o->ptr));
 353         if (sdslen(o->ptr) < 4096)
 354             redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
 355     } else if (o->type == REDIS_LIST) {
 356         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
 357     } else if (o->type == REDIS_SET) {
 358         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
 359     } else if (o->type == REDIS_HASH) {
 360         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
 361     } else if (o->type == REDIS_ZSET) {
 362         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
 363         if (o->encoding == REDIS_ENCODING_SKIPLIST)
 364             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
 365     }
 366 }
 367
 368 void _redisAssertPrintObject(robj *o) {
 369     bugReportStart();
 370     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
 371     redisLogObjectDebugInfo(o);
 372 }
 373
 374 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
 375     if (c) _redisAssertPrintClientInfo(c);
 376     if (o) _redisAssertPrintObject(o);
 377     _redisAssert(estr,file,line);
 378 }
 379
 380 void _redisPanic(char *msg, char *file, int line) {
 381     bugReportStart();
 382     redisLog(REDIS_WARNING,"------------------------------------------------");
 383     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
 384     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
 385 #ifdef HAVE_BACKTRACE
 386     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
 387 #endif
 388     redisLog(REDIS_WARNING,"------------------------------------------------");
 389     *((char*)-1) = 'x';
 390 }
 391
 392 void bugReportStart(void) {
 393     if (server.bug_report_start == 0) {
 394         redisLog(REDIS_WARNING,
 395             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
 396         server.bug_report_start = 1;
 397     }
 398 }
 399
 400 #ifdef HAVE_BACKTRACE
 401 static void *getMcontextEip(ucontext_t *uc) {
 402 #if defined(__FreeBSD__)
 403     return (void*) uc->uc_mcontext.mc_eip;
 404 #elif defined(__dietlibc__)
 405     return (void*) uc->uc_mcontext.eip;
 406 #elif defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
 407   #if __x86_64__
 408     return (void*) uc->uc_mcontext->__ss.__rip;
 409   #elif __i386__
 410     return (void*) uc->uc_mcontext->__ss.__eip;
 411   #else
 412     return (void*) uc->uc_mcontext->__ss.__srr0;
 413   #endif
 414 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
 415   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
 416     return (void*) uc->uc_mcontext->__ss.__rip;
 417   #else
 418     return (void*) uc->uc_mcontext->__ss.__eip;
 419   #endif
 420 #elif defined(__i386__)
 421     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
 422 #elif defined(__X86_64__) || defined(__x86_64__)
 423     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
 424 #elif defined(__ia64__) /* Linux IA64 */
 425     return (void*) uc->uc_mcontext.sc_ip;
 426 #else
 427     return NULL;
 428 #endif
 429 }
 430
 431 void logStackContent(void **sp) {
 432     int i;
 433     for (i = 15; i >= 0; i--) {
 434         if (sizeof(long) == 4)
 435             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", sp+i, sp[i]);
 436         else
 437             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", sp+i, sp[i]);
 438     }
 439 }
 440
 441 void logRegisters(ucontext_t *uc) {
 442     redisLog(REDIS_WARNING, "--- REGISTERS");
 443 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
 444   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
 445     redisLog(REDIS_WARNING,
 446     "\n"
 447     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
 448     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
 449     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
 450     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
 451     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
 452         uc->uc_mcontext->__ss.__rax,
 453         uc->uc_mcontext->__ss.__rbx,
 454         uc->uc_mcontext->__ss.__rcx,
 455         uc->uc_mcontext->__ss.__rdx,
 456         uc->uc_mcontext->__ss.__rdi,
 457         uc->uc_mcontext->__ss.__rsi,
 458         uc->uc_mcontext->__ss.__rbp,
 459         uc->uc_mcontext->__ss.__rsp,
 460         uc->uc_mcontext->__ss.__r8,
 461         uc->uc_mcontext->__ss.__r9,
 462         uc->uc_mcontext->__ss.__r10,
 463         uc->uc_mcontext->__ss.__r11,
 464         uc->uc_mcontext->__ss.__r12,
 465         uc->uc_mcontext->__ss.__r13,
 466         uc->uc_mcontext->__ss.__r14,
 467         uc->uc_mcontext->__ss.__r15,
 468         uc->uc_mcontext->__ss.__rip,
 469         uc->uc_mcontext->__ss.__rflags,
 470         uc->uc_mcontext->__ss.__cs,
 471         uc->uc_mcontext->__ss.__fs,
 472         uc->uc_mcontext->__ss.__gs
 473     );
 474     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
 475   #else
 476     redisLog(REDIS_WARNING,
 477     "\n"
 478     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
 479     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
 480     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
 481     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
 482         uc->uc_mcontext->__ss.__eax,
 483         uc->uc_mcontext->__ss.__ebx,
 484         uc->uc_mcontext->__ss.__ecx,
 485         uc->uc_mcontext->__ss.__edx,
 486         uc->uc_mcontext->__ss.__edi,
 487         uc->uc_mcontext->__ss.__esi,
 488         uc->uc_mcontext->__ss.__ebp,
 489         uc->uc_mcontext->__ss.__esp,
 490         uc->uc_mcontext->__ss.__ss,
 491         uc->uc_mcontext->__ss.__eflags,
 492         uc->uc_mcontext->__ss.__eip,
 493         uc->uc_mcontext->__ss.__cs,
 494         uc->uc_mcontext->__ss.__ds,
 495         uc->uc_mcontext->__ss.__es,
 496         uc->uc_mcontext->__ss.__fs,
 497         uc->uc_mcontext->__ss.__gs
 498     );
 499     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
 500   #endif
 501 #elif defined(__i386__)
 502     redisLog(REDIS_WARNING,
 503     "\n"
 504     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
 505     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
 506     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
 507     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
 508         uc->uc_mcontext.gregs[11],
 509         uc->uc_mcontext.gregs[8],
 510         uc->uc_mcontext.gregs[10],
 511         uc->uc_mcontext.gregs[9],
 512         uc->uc_mcontext.gregs[4],
 513         uc->uc_mcontext.gregs[5],
 514         uc->uc_mcontext.gregs[6],
 515         uc->uc_mcontext.gregs[7],
 516         uc->uc_mcontext.gregs[18],
 517         uc->uc_mcontext.gregs[17],
 518         uc->uc_mcontext.gregs[14],
 519         uc->uc_mcontext.gregs[15],
 520         uc->uc_mcontext.gregs[3],
 521         uc->uc_mcontext.gregs[2],
 522         uc->uc_mcontext.gregs[1],
 523         uc->uc_mcontext.gregs[0]
 524     );
 525     logStackContent((void**)uc->uc_mcontext.gregs[7]);
 526 #elif defined(__X86_64__) || defined(__x86_64__)
 527     redisLog(REDIS_WARNING,
 528     "\n"
 529     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
 530     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
 531     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
 532     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
 533     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
 534         uc->uc_mcontext.gregs[13],
 535         uc->uc_mcontext.gregs[11],
 536         uc->uc_mcontext.gregs[14],
 537         uc->uc_mcontext.gregs[12],
 538         uc->uc_mcontext.gregs[8],
 539         uc->uc_mcontext.gregs[9],
 540         uc->uc_mcontext.gregs[10],
 541         uc->uc_mcontext.gregs[15],
 542         uc->uc_mcontext.gregs[0],
 543         uc->uc_mcontext.gregs[1],
 544         uc->uc_mcontext.gregs[2],
 545         uc->uc_mcontext.gregs[3],
 546         uc->uc_mcontext.gregs[4],
 547         uc->uc_mcontext.gregs[5],
 548         uc->uc_mcontext.gregs[6],
 549         uc->uc_mcontext.gregs[7],
 550         uc->uc_mcontext.gregs[16],
 551         uc->uc_mcontext.gregs[17],
 552         uc->uc_mcontext.gregs[18]
 553     );
 554     logStackContent((void**)uc->uc_mcontext.gregs[15]);
 555 #else
 556     redisLog(REDIS_WARNING,
 557         "  Dumping of registers not supported for this OS/arch");
 558 #endif
 559 }
 560
 561 /* Logs the stack trace using the backtrace() call. */
 562 sds getStackTrace(ucontext_t *uc) {
 563     void *trace[100];
 564     int i, trace_size = 0;
 565     char **messages = NULL;
 566     sds st = sdsempty();
 567
 568     /* Generate the stack trace */
 569     trace_size = backtrace(trace, 100);
 570
 571     /* overwrite sigaction with caller's address */
 572     if (getMcontextEip(uc) != NULL) {
 573         trace[1] = getMcontextEip(uc);
 574     }
 575     messages = backtrace_symbols(trace, trace_size);
 576     for (i=1; i<trace_size; ++i) {
 577         st = sdscat(st,messages[i]);
 578         st = sdscatlen(st,"\n",1);
 579     }
 580     zlibc_free(messages);
 581     return st;
 582 }
 583
 584 /* Log information about the "current" client, that is, the client that is
 585  * currently being served by Redis. May be NULL if Redis is not serving a
 586  * client right now. */
 587 void logCurrentClient(void) {
 588     if (server.current_client == NULL) return;
 589
 590     redisClient *cc = server.current_client;
 591     sds client;
 592     int j;
 593
 594     redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
 595     client = getClientInfoString(cc);
 596     redisLog(REDIS_WARNING,"client: %s", client);
 597     sdsfree(client);
 598     for (j = 0; j < cc->argc; j++) {
 599         robj *decoded;
 600
 601         decoded = getDecodedObject(cc->argv[j]);
 602         redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
 603         decrRefCount(decoded);
 604     }
 605     /* Check if the first argument, usually a key, is found inside the
 606      * selected DB, and if so print info about the associated object. */
 607     if (cc->argc >= 1) {
 608         robj *val, *key;
 609         dictEntry *de;
 610
 611         key = getDecodedObject(cc->argv[1]);
 612         de = dictFind(cc->db->dict, key->ptr);
 613         if (de) {
 614             val = dictGetVal(de);
 615             redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
 616             redisLogObjectDebugInfo(val);
 617         }
 618         decrRefCount(key);
 619     }
 620 }
 621
 622 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
 623     ucontext_t *uc = (ucontext_t*) secret;
 624     sds infostring, clients, st;
 625     struct sigaction act;
 626     REDIS_NOTUSED(info);
 627
 628     bugReportStart();
 629     redisLog(REDIS_WARNING,
 630         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
 631     redisLog(REDIS_WARNING,
 632         "    Failed assertion: %s (%s:%d)", server.assert_failed,
 633                         server.assert_file, server.assert_line);
 634
 635     /* Log the stack trace */
 636     st = getStackTrace(uc);
 637     redisLog(REDIS_WARNING, "--- STACK TRACE\n%s", st);
 638     sdsfree(st);
 639
 640     /* Log INFO and CLIENT LIST */
 641     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
 642     infostring = genRedisInfoString("all");
 643     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
 644         dictGetHashFunctionSeed());
 645     redisLogRaw(REDIS_WARNING, infostring);
 646     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
 647     clients = getAllClientsInfoString();
 648     redisLogRaw(REDIS_WARNING, clients);
 649     sdsfree(infostring);
 650     sdsfree(clients);
 651
 652     /* Log the current client */
 653     logCurrentClient();
 654
 655     /* Log dump of processor registers */
 656     logRegisters(uc);
 657
 658     redisLog(REDIS_WARNING,
 659 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
 660 "       Please report the crash opening an issue on github:\n\n"
 661 "           http://github.com/antirez/redis/issues\n\n"
 662 "  Suspect RAM error? Use redis-server --test-memory to veryfy it.\n\n"
 663 );
 664     /* free(messages); Don't call free() with possibly corrupted memory. */
 665     if (server.daemonize) unlink(server.pidfile);
 666
 667     /* Make sure we exit with the right signal at the end. So for instance
 668      * the core will be dumped if enabled. */
 669     sigemptyset (&act.sa_mask);
 670     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
 671     act.sa_handler = SIG_DFL;
 672     sigaction (sig, &act, NULL);
 673     kill(getpid(),sig);
 674 }
 675 #endif /* HAVE_BACKTRACE */
 676
 677 /* =========================== Software Watchdog ============================ */
 678 #include <sys/time.h>
 679
 680 void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
 681     ucontext_t *uc = (ucontext_t*) secret;
 682     REDIS_NOTUSED(info);
 683     REDIS_NOTUSED(sig);
 684     sds st, log;
 685
 686     log = sdsnew("\n--- WATCHDOG TIMER EXPIRED ---\n");
 687 #ifdef HAVE_BACKTRACE
 688     st = getStackTrace(uc);
 689 #else
 690     st = sdsnew("Sorry: no support for backtrace().\n");
 691 #endif
 692     log = sdscatsds(log,st);
 693     log = sdscat(log,"------\n");
 694     redisLogFromHandler(REDIS_WARNING,log);
 695     sdsfree(st);
 696     sdsfree(log);
 697 }
 698
 699 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
 700  * If a timer is already scheduled, this function will re-schedule it to the
 701  * specified time. If period is 0 the current timer is disabled. */
 702 void watchdogScheduleSignal(int period) {
 703     struct itimerval it;
 704
 705     /* Will stop the timer if period is 0. */
 706     it.it_value.tv_sec = period/1000;
 707     it.it_value.tv_usec = (period%1000)*1000;
 708     /* Don't automatically restart. */
 709     it.it_interval.tv_sec = 0;
 710     it.it_interval.tv_usec = 0;
 711     setitimer(ITIMER_REAL, &it, NULL);
 712 }
 713
 714 /* Enable the software watchdong with the specified period in milliseconds. */
 715 void enableWatchdog(int period) {
 716     if (server.watchdog_period == 0) {
 717         struct sigaction act;
 718
 719         /* Watchdog was actually disabled, so we have to setup the signal
 720          * handler. */
 721         sigemptyset(&act.sa_mask);
 722         act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_SIGINFO;
 723         act.sa_sigaction = watchdogSignalHandler;
 724         sigaction(SIGALRM, &act, NULL);
 725     }
 726     if (period < 200) period = 200; /* We don't accept periods < 200 ms. */
 727     watchdogScheduleSignal(period); /* Adjust the current timer. */
 728     server.watchdog_period = period;
 729 }
 730
 731 /* Disable the software watchdog. */
 732 void disableWatchdog(void) {
 733     struct sigaction act;
 734     if (server.watchdog_period == 0) return; /* Already disabled. */
 735     watchdogScheduleSignal(0); /* Stop the current timer. */
 736
 737     /* Set the signal handler to SIG_IGN, this will also remove pending
 738      * signals from the queue. */
 739     sigemptyset(&act.sa_mask);
 740     act.sa_flags = 0;
 741     act.sa_handler = SIG_IGN;
 742     sigaction(SIGALRM, &act, NULL);
 743     server.watchdog_period = 0;
 744 }