xref: /redis-3.2.3/src/debug.c (revision fceef8e0)
1 /*
2  * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *
8  *   * Redistributions of source code must retain the above copyright notice,
9  *     this list of conditions and the following disclaimer.
10  *   * Redistributions in binary form must reproduce the above copyright
11  *     notice, this list of conditions and the following disclaimer in the
12  *     documentation and/or other materials provided with the distribution.
13  *   * Neither the name of Redis nor the names of its contributors may be used
14  *     to endorse or promote products derived from this software without
15  *     specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include "redis.h"
31 #include "sha1.h"   /* SHA1 is used for DEBUG DIGEST */
32 #include "crc64.h"
33 
34 #include <arpa/inet.h>
35 #include <signal.h>
36 
37 #ifdef HAVE_BACKTRACE
38 #include <execinfo.h>
39 #include <ucontext.h>
40 #include <fcntl.h>
41 #include "bio.h"
42 #endif /* HAVE_BACKTRACE */
43 
44 #ifdef __CYGWIN__
45 #ifndef SA_ONSTACK
46 #define SA_ONSTACK 0x08000000
47 #endif
48 #endif
49 
50 /* ================================= Debugging ============================== */
51 
52 /* Compute the sha1 of string at 's' with 'len' bytes long.
53  * The SHA1 is then xored against the string pointed by digest.
54  * Since xor is commutative, this operation is used in order to
55  * "add" digests relative to unordered elements.
56  *
57  * So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
58 void xorDigest(unsigned char *digest, void *ptr, size_t len) {
59     SHA1_CTX ctx;
60     unsigned char hash[20], *s = ptr;
61     int j;
62 
63     SHA1Init(&ctx);
64     SHA1Update(&ctx,s,len);
65     SHA1Final(hash,&ctx);
66 
67     for (j = 0; j < 20; j++)
68         digest[j] ^= hash[j];
69 }
70 
71 void xorObjectDigest(unsigned char *digest, robj *o) {
72     o = getDecodedObject(o);
73     xorDigest(digest,o->ptr,sdslen(o->ptr));
74     decrRefCount(o);
75 }
76 
77 /* This function instead of just computing the SHA1 and xoring it
78  * against digest, also perform the digest of "digest" itself and
79  * replace the old value with the new one.
80  *
81  * So the final digest will be:
82  *
83  * digest = SHA1(digest xor SHA1(data))
84  *
85  * This function is used every time we want to preserve the order so
86  * that digest(a,b,c,d) will be different than digest(b,c,d,a)
87  *
88  * Also note that mixdigest("foo") followed by mixdigest("bar")
89  * will lead to a different digest compared to "fo", "obar".
90  */
91 void mixDigest(unsigned char *digest, void *ptr, size_t len) {
92     SHA1_CTX ctx;
93     char *s = ptr;
94 
95     xorDigest(digest,s,len);
96     SHA1Init(&ctx);
97     SHA1Update(&ctx,digest,20);
98     SHA1Final(digest,&ctx);
99 }
100 
101 void mixObjectDigest(unsigned char *digest, robj *o) {
102     o = getDecodedObject(o);
103     mixDigest(digest,o->ptr,sdslen(o->ptr));
104     decrRefCount(o);
105 }
106 
107 /* Compute the dataset digest. Since keys, sets elements, hashes elements
108  * are not ordered, we use a trick: every aggregate digest is the xor
109  * of the digests of their elements. This way the order will not change
110  * the result. For list instead we use a feedback entering the output digest
111  * as input in order to ensure that a different ordered list will result in
112  * a different digest. */
113 void computeDatasetDigest(unsigned char *final) {
114     unsigned char digest[20];
115     char buf[128];
116     dictIterator *di = NULL;
117     dictEntry *de;
118     int j;
119     uint32_t aux;
120 
121     memset(final,0,20); /* Start with a clean result */
122 
123     for (j = 0; j < server.dbnum; j++) {
124         redisDb *db = server.db+j;
125 
126         if (dictSize(db->dict) == 0) continue;
127         di = dictGetIterator(db->dict);
128 
129         /* hash the DB id, so the same dataset moved in a different
130          * DB will lead to a different digest */
131         aux = htonl(j);
132         mixDigest(final,&aux,sizeof(aux));
133 
134         /* Iterate this DB writing every entry */
135         while((de = dictNext(di)) != NULL) {
136             sds key;
137             robj *keyobj, *o;
138             long long expiretime;
139 
140             memset(digest,0,20); /* This key-val digest */
141             key = dictGetKey(de);
142             keyobj = createStringObject(key,sdslen(key));
143 
144             mixDigest(digest,key,sdslen(key));
145 
146             o = dictGetVal(de);
147 
148             aux = htonl(o->type);
149             mixDigest(digest,&aux,sizeof(aux));
150             expiretime = getExpire(db,keyobj);
151 
152             /* Save the key and associated value */
153             if (o->type == REDIS_STRING) {
154                 mixObjectDigest(digest,o);
155             } else if (o->type == REDIS_LIST) {
156                 listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
157                 listTypeEntry entry;
158                 while(listTypeNext(li,&entry)) {
159                     robj *eleobj = listTypeGet(&entry);
160                     mixObjectDigest(digest,eleobj);
161                     decrRefCount(eleobj);
162                 }
163                 listTypeReleaseIterator(li);
164             } else if (o->type == REDIS_SET) {
165                 setTypeIterator *si = setTypeInitIterator(o);
166                 robj *ele;
167                 while((ele = setTypeNextObject(si)) != NULL) {
168                     xorObjectDigest(digest,ele);
169                     decrRefCount(ele);
170                 }
171                 setTypeReleaseIterator(si);
172             } else if (o->type == REDIS_ZSET) {
173                 unsigned char eledigest[20];
174 
175                 if (o->encoding == REDIS_ENCODING_ZIPLIST) {
176                     unsigned char *zl = o->ptr;
177                     unsigned char *eptr, *sptr;
178                     unsigned char *vstr;
179                     unsigned int vlen;
180                     long long vll;
181                     double score;
182 
183                     eptr = ziplistIndex(zl,0);
184                     redisAssert(eptr != NULL);
185                     sptr = ziplistNext(zl,eptr);
186                     redisAssert(sptr != NULL);
187 
188                     while (eptr != NULL) {
189                         redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
190                         score = zzlGetScore(sptr);
191 
192                         memset(eledigest,0,20);
193                         if (vstr != NULL) {
194                             mixDigest(eledigest,vstr,vlen);
195                         } else {
196                             ll2string(buf,sizeof(buf),vll);
197                             mixDigest(eledigest,buf,strlen(buf));
198                         }
199 
200                         snprintf(buf,sizeof(buf),"%.17g",score);
201                         mixDigest(eledigest,buf,strlen(buf));
202                         xorDigest(digest,eledigest,20);
203                         zzlNext(zl,&eptr,&sptr);
204                     }
205                 } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
206                     zset *zs = o->ptr;
207                     dictIterator *di = dictGetIterator(zs->dict);
208                     dictEntry *de;
209 
210                     while((de = dictNext(di)) != NULL) {
211                         robj *eleobj = dictGetKey(de);
212                         double *score = dictGetVal(de);
213 
214                         snprintf(buf,sizeof(buf),"%.17g",*score);
215                         memset(eledigest,0,20);
216                         mixObjectDigest(eledigest,eleobj);
217                         mixDigest(eledigest,buf,strlen(buf));
218                         xorDigest(digest,eledigest,20);
219                     }
220                     dictReleaseIterator(di);
221                 } else {
222                     redisPanic("Unknown sorted set encoding");
223                 }
224             } else if (o->type == REDIS_HASH) {
225                 hashTypeIterator *hi;
226                 robj *obj;
227 
228                 hi = hashTypeInitIterator(o);
229                 while (hashTypeNext(hi) != REDIS_ERR) {
230                     unsigned char eledigest[20];
231 
232                     memset(eledigest,0,20);
233                     obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
234                     mixObjectDigest(eledigest,obj);
235                     decrRefCount(obj);
236                     obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
237                     mixObjectDigest(eledigest,obj);
238                     decrRefCount(obj);
239                     xorDigest(digest,eledigest,20);
240                 }
241                 hashTypeReleaseIterator(hi);
242             } else {
243                 redisPanic("Unknown object type");
244             }
245             /* If the key has an expire, add it to the mix */
246             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
247             /* We can finally xor the key-val digest to the final digest */
248             xorDigest(final,digest,20);
249             decrRefCount(keyobj);
250         }
251         dictReleaseIterator(di);
252     }
253 }
254 
255 void debugCommand(redisClient *c) {
256     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
257         *((char*)-1) = 'x';
258     } else if (!strcasecmp(c->argv[1]->ptr,"oom")) {
259         void *ptr = zmalloc(ULONG_MAX); /* Should trigger an out of memory. */
260         zfree(ptr);
261         addReply(c,shared.ok);
262     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
263         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
264         redisAssertWithInfo(c,c->argv[0],1 == 2);
265     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
266         if (rdbSave(server.rdb_filename) != REDIS_OK) {
267             addReply(c,shared.err);
268             return;
269         }
270         emptyDb(NULL);
271         if (rdbLoad(server.rdb_filename) != REDIS_OK) {
272             addReplyError(c,"Error trying to load the RDB dump");
273             return;
274         }
275         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
276         addReply(c,shared.ok);
277     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
278         emptyDb(NULL);
279         if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
280             addReply(c,shared.err);
281             return;
282         }
283         server.dirty = 0; /* Prevent AOF / replication */
284         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
285         addReply(c,shared.ok);
286     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
287         dictEntry *de;
288         robj *val;
289         char *strenc;
290 
291         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
292             addReply(c,shared.nokeyerr);
293             return;
294         }
295         val = dictGetVal(de);
296         strenc = strEncoding(val->encoding);
297 
298         addReplyStatusFormat(c,
299             "Value at:%p refcount:%d "
300             "encoding:%s serializedlength:%lld "
301             "lru:%d lru_seconds_idle:%llu",
302             (void*)val, val->refcount,
303             strenc, (long long) rdbSavedObjectLen(val),
304             val->lru, estimateObjectIdleTime(val));
305     } else if (!strcasecmp(c->argv[1]->ptr,"sdslen") && c->argc == 3) {
306         dictEntry *de;
307         robj *val;
308         sds key;
309 
310         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
311             addReply(c,shared.nokeyerr);
312             return;
313         }
314         val = dictGetVal(de);
315         key = dictGetKey(de);
316 
317         if (val->type != REDIS_STRING || !sdsEncodedObject(val)) {
318             addReplyError(c,"Not an sds encoded string.");
319         } else {
320             addReplyStatusFormat(c,
321                 "key_sds_len:%lld, key_sds_avail:%lld, "
322                 "val_sds_len:%lld, val_sds_avail:%lld",
323                 (long long) sdslen(key),
324                 (long long) sdsavail(key),
325                 (long long) sdslen(val->ptr),
326                 (long long) sdsavail(val->ptr));
327         }
328     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
329         long keys, j;
330         robj *key, *val;
331         char buf[128];
332 
333         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
334             return;
335         dictExpand(c->db->dict,keys);
336         for (j = 0; j < keys; j++) {
337             snprintf(buf,sizeof(buf),"key:%lu",j);
338             key = createStringObject(buf,strlen(buf));
339             if (lookupKeyRead(c->db,key) != NULL) {
340                 decrRefCount(key);
341                 continue;
342             }
343             snprintf(buf,sizeof(buf),"value:%lu",j);
344             val = createStringObject(buf,strlen(buf));
345             dbAdd(c->db,key,val);
346             decrRefCount(key);
347         }
348         addReply(c,shared.ok);
349     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
350         unsigned char digest[20];
351         sds d = sdsempty();
352         int j;
353 
354         computeDatasetDigest(digest);
355         for (j = 0; j < 20; j++)
356             d = sdscatprintf(d, "%02x",digest[j]);
357         addReplyStatus(c,d);
358         sdsfree(d);
359     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
360         double dtime = strtod(c->argv[2]->ptr,NULL);
361         long long utime = dtime*1000000;
362         struct timespec tv;
363 
364         tv.tv_sec = utime / 1000000;
365         tv.tv_nsec = (utime % 1000000) * 1000;
366         nanosleep(&tv, NULL);
367         addReply(c,shared.ok);
368     } else if (!strcasecmp(c->argv[1]->ptr,"set-active-expire") &&
369                c->argc == 3)
370     {
371         server.active_expire_enabled = atoi(c->argv[2]->ptr);
372         addReply(c,shared.ok);
373     } else if (!strcasecmp(c->argv[1]->ptr,"cmdkeys") && c->argc >= 3) {
374         struct redisCommand *cmd = lookupCommand(c->argv[2]->ptr);
375         int *keys, numkeys, j;
376 
377         if (!cmd) {
378             addReplyError(c,"Invalid command specified");
379             return;
380         } else if ((cmd->arity > 0 && cmd->arity != c->argc-2) ||
381                    ((c->argc-2) < -cmd->arity))
382         {
383             addReplyError(c,"Invalid number of arguments specified for command");
384             return;
385         }
386 
387         keys = getKeysFromCommand(cmd,c->argv+2,c->argc-2,&numkeys);
388         addReplyMultiBulkLen(c,numkeys);
389         for (j = 0; j < numkeys; j++) addReplyBulk(c,c->argv[keys[j]+2]);
390         getKeysFreeResult(keys);
391     } else if (!strcasecmp(c->argv[1]->ptr,"error") && c->argc == 3) {
392         sds errstr = sdsnewlen("-",1);
393 
394         errstr = sdscatsds(errstr,c->argv[2]->ptr);
395         errstr = sdsmapchars(errstr,"\n\r","  ",2); /* no newlines in errors. */
396         errstr = sdscatlen(errstr,"\r\n",2);
397         addReplySds(c,errstr);
398     } else {
399         addReplyErrorFormat(c, "Unknown DEBUG subcommand or wrong number of arguments for '%s'",
400             (char*)c->argv[1]->ptr);
401     }
402 }
403 
404 /* =========================== Crash handling  ============================== */
405 
406 void _redisAssert(char *estr, char *file, int line) {
407     bugReportStart();
408     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
409     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
410 #ifdef HAVE_BACKTRACE
411     server.assert_failed = estr;
412     server.assert_file = file;
413     server.assert_line = line;
414     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
415 #endif
416     *((char*)-1) = 'x';
417 }
418 
419 void _redisAssertPrintClientInfo(redisClient *c) {
420     int j;
421 
422     bugReportStart();
423     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
424     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
425     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
426     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
427     for (j=0; j < c->argc; j++) {
428         char buf[128];
429         char *arg;
430 
431         if (c->argv[j]->type == REDIS_STRING && sdsEncodedObject(c->argv[j])) {
432             arg = (char*) c->argv[j]->ptr;
433         } else {
434             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
435                 c->argv[j]->type, c->argv[j]->encoding);
436             arg = buf;
437         }
438         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
439             j, arg, c->argv[j]->refcount);
440     }
441 }
442 
443 void redisLogObjectDebugInfo(robj *o) {
444     redisLog(REDIS_WARNING,"Object type: %d", o->type);
445     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
446     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
447     if (o->type == REDIS_STRING && sdsEncodedObject(o)) {
448         redisLog(REDIS_WARNING,"Object raw string len: %zu", sdslen(o->ptr));
449         if (sdslen(o->ptr) < 4096) {
450             sds repr = sdscatrepr(sdsempty(),o->ptr,sdslen(o->ptr));
451             redisLog(REDIS_WARNING,"Object raw string content: %s", repr);
452             sdsfree(repr);
453         }
454     } else if (o->type == REDIS_LIST) {
455         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
456     } else if (o->type == REDIS_SET) {
457         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
458     } else if (o->type == REDIS_HASH) {
459         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
460     } else if (o->type == REDIS_ZSET) {
461         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
462         if (o->encoding == REDIS_ENCODING_SKIPLIST)
463             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
464     }
465 }
466 
467 void _redisAssertPrintObject(robj *o) {
468     bugReportStart();
469     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
470     redisLogObjectDebugInfo(o);
471 }
472 
473 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
474     if (c) _redisAssertPrintClientInfo(c);
475     if (o) _redisAssertPrintObject(o);
476     _redisAssert(estr,file,line);
477 }
478 
479 void _redisPanic(char *msg, char *file, int line) {
480     bugReportStart();
481     redisLog(REDIS_WARNING,"------------------------------------------------");
482     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
483     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
484 #ifdef HAVE_BACKTRACE
485     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
486 #endif
487     redisLog(REDIS_WARNING,"------------------------------------------------");
488     *((char*)-1) = 'x';
489 }
490 
491 void bugReportStart(void) {
492     if (server.bug_report_start == 0) {
493         redisLog(REDIS_WARNING,
494             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
495         server.bug_report_start = 1;
496     }
497 }
498 
499 #ifdef HAVE_BACKTRACE
500 static void *getMcontextEip(ucontext_t *uc) {
501 #if defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
502     /* OSX < 10.6 */
503     #if defined(__x86_64__)
504     return (void*) uc->uc_mcontext->__ss.__rip;
505     #elif defined(__i386__)
506     return (void*) uc->uc_mcontext->__ss.__eip;
507     #else
508     return (void*) uc->uc_mcontext->__ss.__srr0;
509     #endif
510 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
511     /* OSX >= 10.6 */
512     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
513     return (void*) uc->uc_mcontext->__ss.__rip;
514     #else
515     return (void*) uc->uc_mcontext->__ss.__eip;
516     #endif
517 #elif defined(__linux__)
518     /* Linux */
519     #if defined(__i386__)
520     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
521     #elif defined(__X86_64__) || defined(__x86_64__)
522     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
523     #elif defined(__ia64__) /* Linux IA64 */
524     return (void*) uc->uc_mcontext.sc_ip;
525     #endif
526 #else
527     return NULL;
528 #endif
529 }
530 
531 void logStackContent(void **sp) {
532     int i;
533     for (i = 15; i >= 0; i--) {
534         unsigned long addr = (unsigned long) sp+i;
535         unsigned long val = (unsigned long) sp[i];
536 
537         if (sizeof(long) == 4)
538             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", addr, val);
539         else
540             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", addr, val);
541     }
542 }
543 
544 void logRegisters(ucontext_t *uc) {
545     redisLog(REDIS_WARNING, "--- REGISTERS");
546 
547 /* OSX */
548 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
549   /* OSX AMD64 */
550     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
551     redisLog(REDIS_WARNING,
552     "\n"
553     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
554     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
555     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
556     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
557     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
558         (unsigned long) uc->uc_mcontext->__ss.__rax,
559         (unsigned long) uc->uc_mcontext->__ss.__rbx,
560         (unsigned long) uc->uc_mcontext->__ss.__rcx,
561         (unsigned long) uc->uc_mcontext->__ss.__rdx,
562         (unsigned long) uc->uc_mcontext->__ss.__rdi,
563         (unsigned long) uc->uc_mcontext->__ss.__rsi,
564         (unsigned long) uc->uc_mcontext->__ss.__rbp,
565         (unsigned long) uc->uc_mcontext->__ss.__rsp,
566         (unsigned long) uc->uc_mcontext->__ss.__r8,
567         (unsigned long) uc->uc_mcontext->__ss.__r9,
568         (unsigned long) uc->uc_mcontext->__ss.__r10,
569         (unsigned long) uc->uc_mcontext->__ss.__r11,
570         (unsigned long) uc->uc_mcontext->__ss.__r12,
571         (unsigned long) uc->uc_mcontext->__ss.__r13,
572         (unsigned long) uc->uc_mcontext->__ss.__r14,
573         (unsigned long) uc->uc_mcontext->__ss.__r15,
574         (unsigned long) uc->uc_mcontext->__ss.__rip,
575         (unsigned long) uc->uc_mcontext->__ss.__rflags,
576         (unsigned long) uc->uc_mcontext->__ss.__cs,
577         (unsigned long) uc->uc_mcontext->__ss.__fs,
578         (unsigned long) uc->uc_mcontext->__ss.__gs
579     );
580     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
581     #else
582     /* OSX x86 */
583     redisLog(REDIS_WARNING,
584     "\n"
585     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
586     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
587     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
588     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
589         (unsigned long) uc->uc_mcontext->__ss.__eax,
590         (unsigned long) uc->uc_mcontext->__ss.__ebx,
591         (unsigned long) uc->uc_mcontext->__ss.__ecx,
592         (unsigned long) uc->uc_mcontext->__ss.__edx,
593         (unsigned long) uc->uc_mcontext->__ss.__edi,
594         (unsigned long) uc->uc_mcontext->__ss.__esi,
595         (unsigned long) uc->uc_mcontext->__ss.__ebp,
596         (unsigned long) uc->uc_mcontext->__ss.__esp,
597         (unsigned long) uc->uc_mcontext->__ss.__ss,
598         (unsigned long) uc->uc_mcontext->__ss.__eflags,
599         (unsigned long) uc->uc_mcontext->__ss.__eip,
600         (unsigned long) uc->uc_mcontext->__ss.__cs,
601         (unsigned long) uc->uc_mcontext->__ss.__ds,
602         (unsigned long) uc->uc_mcontext->__ss.__es,
603         (unsigned long) uc->uc_mcontext->__ss.__fs,
604         (unsigned long) uc->uc_mcontext->__ss.__gs
605     );
606     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
607     #endif
608 /* Linux */
609 #elif defined(__linux__)
610     /* Linux x86 */
611     #if defined(__i386__)
612     redisLog(REDIS_WARNING,
613     "\n"
614     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
615     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
616     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
617     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
618         (unsigned long) uc->uc_mcontext.gregs[11],
619         (unsigned long) uc->uc_mcontext.gregs[8],
620         (unsigned long) uc->uc_mcontext.gregs[10],
621         (unsigned long) uc->uc_mcontext.gregs[9],
622         (unsigned long) uc->uc_mcontext.gregs[4],
623         (unsigned long) uc->uc_mcontext.gregs[5],
624         (unsigned long) uc->uc_mcontext.gregs[6],
625         (unsigned long) uc->uc_mcontext.gregs[7],
626         (unsigned long) uc->uc_mcontext.gregs[18],
627         (unsigned long) uc->uc_mcontext.gregs[17],
628         (unsigned long) uc->uc_mcontext.gregs[14],
629         (unsigned long) uc->uc_mcontext.gregs[15],
630         (unsigned long) uc->uc_mcontext.gregs[3],
631         (unsigned long) uc->uc_mcontext.gregs[2],
632         (unsigned long) uc->uc_mcontext.gregs[1],
633         (unsigned long) uc->uc_mcontext.gregs[0]
634     );
635     logStackContent((void**)uc->uc_mcontext.gregs[7]);
636     #elif defined(__X86_64__) || defined(__x86_64__)
637     /* Linux AMD64 */
638     redisLog(REDIS_WARNING,
639     "\n"
640     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
641     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
642     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
643     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
644     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
645         (unsigned long) uc->uc_mcontext.gregs[13],
646         (unsigned long) uc->uc_mcontext.gregs[11],
647         (unsigned long) uc->uc_mcontext.gregs[14],
648         (unsigned long) uc->uc_mcontext.gregs[12],
649         (unsigned long) uc->uc_mcontext.gregs[8],
650         (unsigned long) uc->uc_mcontext.gregs[9],
651         (unsigned long) uc->uc_mcontext.gregs[10],
652         (unsigned long) uc->uc_mcontext.gregs[15],
653         (unsigned long) uc->uc_mcontext.gregs[0],
654         (unsigned long) uc->uc_mcontext.gregs[1],
655         (unsigned long) uc->uc_mcontext.gregs[2],
656         (unsigned long) uc->uc_mcontext.gregs[3],
657         (unsigned long) uc->uc_mcontext.gregs[4],
658         (unsigned long) uc->uc_mcontext.gregs[5],
659         (unsigned long) uc->uc_mcontext.gregs[6],
660         (unsigned long) uc->uc_mcontext.gregs[7],
661         (unsigned long) uc->uc_mcontext.gregs[16],
662         (unsigned long) uc->uc_mcontext.gregs[17],
663         (unsigned long) uc->uc_mcontext.gregs[18]
664     );
665     logStackContent((void**)uc->uc_mcontext.gregs[15]);
666     #endif
667 #else
668     redisLog(REDIS_WARNING,
669         "  Dumping of registers not supported for this OS/arch");
670 #endif
671 }
672 
673 /* Logs the stack trace using the backtrace() call. This function is designed
674  * to be called from signal handlers safely. */
675 void logStackTrace(ucontext_t *uc) {
676     void *trace[100];
677     int trace_size = 0, fd;
678     int log_to_stdout = server.logfile[0] == '\0';
679 
680     /* Open the log file in append mode. */
681     fd = log_to_stdout ?
682         STDOUT_FILENO :
683         open(server.logfile, O_APPEND|O_CREAT|O_WRONLY, 0644);
684     if (fd == -1) return;
685 
686     /* Generate the stack trace */
687     trace_size = backtrace(trace, 100);
688 
689     /* overwrite sigaction with caller's address */
690     if (getMcontextEip(uc) != NULL)
691         trace[1] = getMcontextEip(uc);
692 
693     /* Write symbols to log file */
694     backtrace_symbols_fd(trace, trace_size, fd);
695 
696     /* Cleanup */
697     if (!log_to_stdout) close(fd);
698 }
699 
700 /* Log information about the "current" client, that is, the client that is
701  * currently being served by Redis. May be NULL if Redis is not serving a
702  * client right now. */
703 void logCurrentClient(void) {
704     if (server.current_client == NULL) return;
705 
706     redisClient *cc = server.current_client;
707     sds client;
708     int j;
709 
710     redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
711     client = catClientInfoString(sdsempty(),cc);
712     redisLog(REDIS_WARNING,"client: %s", client);
713     sdsfree(client);
714     for (j = 0; j < cc->argc; j++) {
715         robj *decoded;
716 
717         decoded = getDecodedObject(cc->argv[j]);
718         redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
719         decrRefCount(decoded);
720     }
721     /* Check if the first argument, usually a key, is found inside the
722      * selected DB, and if so print info about the associated object. */
723     if (cc->argc >= 1) {
724         robj *val, *key;
725         dictEntry *de;
726 
727         key = getDecodedObject(cc->argv[1]);
728         de = dictFind(cc->db->dict, key->ptr);
729         if (de) {
730             val = dictGetVal(de);
731             redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", (char*)key->ptr);
732             redisLogObjectDebugInfo(val);
733         }
734         decrRefCount(key);
735     }
736 }
737 
738 #if defined(HAVE_PROC_MAPS)
739 void memtest_non_destructive_invert(void *addr, size_t size);
740 void memtest_non_destructive_swap(void *addr, size_t size);
741 #define MEMTEST_MAX_REGIONS 128
742 
743 int memtest_test_linux_anonymous_maps(void) {
744     FILE *fp = fopen("/proc/self/maps","r");
745     char line[1024];
746     size_t start_addr, end_addr, size;
747     size_t start_vect[MEMTEST_MAX_REGIONS];
748     size_t size_vect[MEMTEST_MAX_REGIONS];
749     int regions = 0, j;
750     uint64_t crc1 = 0, crc2 = 0, crc3 = 0;
751 
752     while(fgets(line,sizeof(line),fp) != NULL) {
753         char *start, *end, *p = line;
754 
755         start = p;
756         p = strchr(p,'-');
757         if (!p) continue;
758         *p++ = '\0';
759         end = p;
760         p = strchr(p,' ');
761         if (!p) continue;
762         *p++ = '\0';
763         if (strstr(p,"stack") ||
764             strstr(p,"vdso") ||
765             strstr(p,"vsyscall")) continue;
766         if (!strstr(p,"00:00")) continue;
767         if (!strstr(p,"rw")) continue;
768 
769         start_addr = strtoul(start,NULL,16);
770         end_addr = strtoul(end,NULL,16);
771         size = end_addr-start_addr;
772 
773         start_vect[regions] = start_addr;
774         size_vect[regions] = size;
775         printf("Testing %lx %lu\n", (unsigned long) start_vect[regions],
776                                     (unsigned long) size_vect[regions]);
777         regions++;
778     }
779 
780     /* Test all the regions as an unique sequential region.
781      * 1) Take the CRC64 of the memory region. */
782     for (j = 0; j < regions; j++) {
783         crc1 = crc64(crc1,(void*)start_vect[j],size_vect[j]);
784     }
785 
786     /* 2) Invert bits, swap adjacent words, swap again, invert bits.
787      * This is the error amplification step. */
788     for (j = 0; j < regions; j++)
789         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
790     for (j = 0; j < regions; j++)
791         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
792     for (j = 0; j < regions; j++)
793         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
794     for (j = 0; j < regions; j++)
795         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
796 
797     /* 3) Take the CRC64 sum again. */
798     for (j = 0; j < regions; j++)
799         crc2 = crc64(crc2,(void*)start_vect[j],size_vect[j]);
800 
801     /* 4) Swap + Swap again */
802     for (j = 0; j < regions; j++)
803         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
804     for (j = 0; j < regions; j++)
805         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
806 
807     /* 5) Take the CRC64 sum again. */
808     for (j = 0; j < regions; j++)
809         crc3 = crc64(crc3,(void*)start_vect[j],size_vect[j]);
810 
811     /* NOTE: It is very important to close the file descriptor only now
812      * because closing it before may result into unmapping of some memory
813      * region that we are testing. */
814     fclose(fp);
815 
816     /* If the two CRC are not the same, we trapped a memory error. */
817     return crc1 != crc2 || crc2 != crc3;
818 }
819 #endif
820 
821 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
822     ucontext_t *uc = (ucontext_t*) secret;
823     sds infostring, clients;
824     struct sigaction act;
825     REDIS_NOTUSED(info);
826 
827     bugReportStart();
828     redisLog(REDIS_WARNING,
829         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
830     redisLog(REDIS_WARNING,
831         "    Failed assertion: %s (%s:%d)", server.assert_failed,
832                         server.assert_file, server.assert_line);
833 
834     /* Log the stack trace */
835     redisLog(REDIS_WARNING, "--- STACK TRACE");
836     logStackTrace(uc);
837 
838     /* Log INFO and CLIENT LIST */
839     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
840     infostring = genRedisInfoString("all");
841     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
842         dictGetHashFunctionSeed());
843     redisLogRaw(REDIS_WARNING, infostring);
844     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
845     clients = getAllClientsInfoString();
846     redisLogRaw(REDIS_WARNING, clients);
847     sdsfree(infostring);
848     sdsfree(clients);
849 
850     /* Log the current client */
851     logCurrentClient();
852 
853     /* Log dump of processor registers */
854     logRegisters(uc);
855 
856 #if defined(HAVE_PROC_MAPS)
857     /* Test memory */
858     redisLog(REDIS_WARNING, "--- FAST MEMORY TEST");
859     bioKillThreads();
860     if (memtest_test_linux_anonymous_maps()) {
861         redisLog(REDIS_WARNING,
862             "!!! MEMORY ERROR DETECTED! Check your memory ASAP !!!");
863     } else {
864         redisLog(REDIS_WARNING,
865             "Fast memory test PASSED, however your memory can still be broken. Please run a memory test for several hours if possible.");
866     }
867 #endif
868 
869     redisLog(REDIS_WARNING,
870 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
871 "       Please report the crash opening an issue on github:\n\n"
872 "           http://github.com/antirez/redis/issues\n\n"
873 "  Suspect RAM error? Use redis-server --test-memory to verify it.\n\n"
874 );
875     /* free(messages); Don't call free() with possibly corrupted memory. */
876     if (server.daemonize) unlink(server.pidfile);
877 
878     /* Make sure we exit with the right signal at the end. So for instance
879      * the core will be dumped if enabled. */
880     sigemptyset (&act.sa_mask);
881     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
882     act.sa_handler = SIG_DFL;
883     sigaction (sig, &act, NULL);
884     kill(getpid(),sig);
885 }
886 #endif /* HAVE_BACKTRACE */
887 
888 /* ==================== Logging functions for debugging ===================== */
889 
890 void redisLogHexDump(int level, char *descr, void *value, size_t len) {
891     char buf[65], *b;
892     unsigned char *v = value;
893     char charset[] = "0123456789abcdef";
894 
895     redisLog(level,"%s (hexdump):", descr);
896     b = buf;
897     while(len) {
898         b[0] = charset[(*v)>>4];
899         b[1] = charset[(*v)&0xf];
900         b[2] = '\0';
901         b += 2;
902         len--;
903         v++;
904         if (b-buf == 64 || len == 0) {
905             redisLogRaw(level|REDIS_LOG_RAW,buf);
906             b = buf;
907         }
908     }
909     redisLogRaw(level|REDIS_LOG_RAW,"\n");
910 }
911 
912 /* =========================== Software Watchdog ============================ */
913 #include <sys/time.h>
914 
915 void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
916 #ifdef HAVE_BACKTRACE
917     ucontext_t *uc = (ucontext_t*) secret;
918 #endif
919     REDIS_NOTUSED(info);
920     REDIS_NOTUSED(sig);
921 
922     redisLogFromHandler(REDIS_WARNING,"\n--- WATCHDOG TIMER EXPIRED ---");
923 #ifdef HAVE_BACKTRACE
924     logStackTrace(uc);
925 #else
926     redisLogFromHandler(REDIS_WARNING,"Sorry: no support for backtrace().");
927 #endif
928     redisLogFromHandler(REDIS_WARNING,"--------\n");
929 }
930 
931 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
932  * If a timer is already scheduled, this function will re-schedule it to the
933  * specified time. If period is 0 the current timer is disabled. */
934 void watchdogScheduleSignal(int period) {
935     struct itimerval it;
936 
937     /* Will stop the timer if period is 0. */
938     it.it_value.tv_sec = period/1000;
939     it.it_value.tv_usec = (period%1000)*1000;
940     /* Don't automatically restart. */
941     it.it_interval.tv_sec = 0;
942     it.it_interval.tv_usec = 0;
943     setitimer(ITIMER_REAL, &it, NULL);
944 }
945 
946 /* Enable the software watchdog with the specified period in milliseconds. */
947 void enableWatchdog(int period) {
948     int min_period;
949 
950     if (server.watchdog_period == 0) {
951         struct sigaction act;
952 
953         /* Watchdog was actually disabled, so we have to setup the signal
954          * handler. */
955         sigemptyset(&act.sa_mask);
956         act.sa_flags = SA_ONSTACK | SA_SIGINFO;
957         act.sa_sigaction = watchdogSignalHandler;
958         sigaction(SIGALRM, &act, NULL);
959     }
960     /* If the configured period is smaller than twice the timer period, it is
961      * too short for the software watchdog to work reliably. Fix it now
962      * if needed. */
963     min_period = (1000/server.hz)*2;
964     if (period < min_period) period = min_period;
965     watchdogScheduleSignal(period); /* Adjust the current timer. */
966     server.watchdog_period = period;
967 }
968 
969 /* Disable the software watchdog. */
970 void disableWatchdog(void) {
971     struct sigaction act;
972     if (server.watchdog_period == 0) return; /* Already disabled. */
973     watchdogScheduleSignal(0); /* Stop the current timer. */
974 
975     /* Set the signal handler to SIG_IGN, this will also remove pending
976      * signals from the queue. */
977     sigemptyset(&act.sa_mask);
978     act.sa_flags = 0;
979     act.sa_handler = SIG_IGN;
980     sigaction(SIGALRM, &act, NULL);
981     server.watchdog_period = 0;
982 }
983