xref: /redis-3.2.3/src/debug.c (revision efbe1739)
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 /* ================================= Debugging ============================== */
45 
46 /* Compute the sha1 of string at 's' with 'len' bytes long.
47  * The SHA1 is then xored against the string pointed by digest.
48  * Since xor is commutative, this operation is used in order to
49  * "add" digests relative to unordered elements.
50  *
51  * So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
52 void xorDigest(unsigned char *digest, void *ptr, size_t len) {
53     SHA1_CTX ctx;
54     unsigned char hash[20], *s = ptr;
55     int j;
56 
57     SHA1Init(&ctx);
58     SHA1Update(&ctx,s,len);
59     SHA1Final(hash,&ctx);
60 
61     for (j = 0; j < 20; j++)
62         digest[j] ^= hash[j];
63 }
64 
65 void xorObjectDigest(unsigned char *digest, robj *o) {
66     o = getDecodedObject(o);
67     xorDigest(digest,o->ptr,sdslen(o->ptr));
68     decrRefCount(o);
69 }
70 
71 /* This function instead of just computing the SHA1 and xoring it
72  * against digest, also perform the digest of "digest" itself and
73  * replace the old value with the new one.
74  *
75  * So the final digest will be:
76  *
77  * digest = SHA1(digest xor SHA1(data))
78  *
79  * This function is used every time we want to preserve the order so
80  * that digest(a,b,c,d) will be different than digest(b,c,d,a)
81  *
82  * Also note that mixdigest("foo") followed by mixdigest("bar")
83  * will lead to a different digest compared to "fo", "obar".
84  */
85 void mixDigest(unsigned char *digest, void *ptr, size_t len) {
86     SHA1_CTX ctx;
87     char *s = ptr;
88 
89     xorDigest(digest,s,len);
90     SHA1Init(&ctx);
91     SHA1Update(&ctx,digest,20);
92     SHA1Final(digest,&ctx);
93 }
94 
95 void mixObjectDigest(unsigned char *digest, robj *o) {
96     o = getDecodedObject(o);
97     mixDigest(digest,o->ptr,sdslen(o->ptr));
98     decrRefCount(o);
99 }
100 
101 /* Compute the dataset digest. Since keys, sets elements, hashes elements
102  * are not ordered, we use a trick: every aggregate digest is the xor
103  * of the digests of their elements. This way the order will not change
104  * the result. For list instead we use a feedback entering the output digest
105  * as input in order to ensure that a different ordered list will result in
106  * a different digest. */
107 void computeDatasetDigest(unsigned char *final) {
108     unsigned char digest[20];
109     char buf[128];
110     dictIterator *di = NULL;
111     dictEntry *de;
112     int j;
113     uint32_t aux;
114 
115     memset(final,0,20); /* Start with a clean result */
116 
117     for (j = 0; j < server.dbnum; j++) {
118         redisDb *db = server.db+j;
119 
120         if (dictSize(db->dict) == 0) continue;
121         di = dictGetIterator(db->dict);
122 
123         /* hash the DB id, so the same dataset moved in a different
124          * DB will lead to a different digest */
125         aux = htonl(j);
126         mixDigest(final,&aux,sizeof(aux));
127 
128         /* Iterate this DB writing every entry */
129         while((de = dictNext(di)) != NULL) {
130             sds key;
131             robj *keyobj, *o;
132             long long expiretime;
133 
134             memset(digest,0,20); /* This key-val digest */
135             key = dictGetKey(de);
136             keyobj = createStringObject(key,sdslen(key));
137 
138             mixDigest(digest,key,sdslen(key));
139 
140             o = dictGetVal(de);
141 
142             aux = htonl(o->type);
143             mixDigest(digest,&aux,sizeof(aux));
144             expiretime = getExpire(db,keyobj);
145 
146             /* Save the key and associated value */
147             if (o->type == REDIS_STRING) {
148                 mixObjectDigest(digest,o);
149             } else if (o->type == REDIS_LIST) {
150                 listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
151                 listTypeEntry entry;
152                 while(listTypeNext(li,&entry)) {
153                     robj *eleobj = listTypeGet(&entry);
154                     mixObjectDigest(digest,eleobj);
155                     decrRefCount(eleobj);
156                 }
157                 listTypeReleaseIterator(li);
158             } else if (o->type == REDIS_SET) {
159                 setTypeIterator *si = setTypeInitIterator(o);
160                 robj *ele;
161                 while((ele = setTypeNextObject(si)) != NULL) {
162                     xorObjectDigest(digest,ele);
163                     decrRefCount(ele);
164                 }
165                 setTypeReleaseIterator(si);
166             } else if (o->type == REDIS_ZSET) {
167                 unsigned char eledigest[20];
168 
169                 if (o->encoding == REDIS_ENCODING_ZIPLIST) {
170                     unsigned char *zl = o->ptr;
171                     unsigned char *eptr, *sptr;
172                     unsigned char *vstr;
173                     unsigned int vlen;
174                     long long vll;
175                     double score;
176 
177                     eptr = ziplistIndex(zl,0);
178                     redisAssert(eptr != NULL);
179                     sptr = ziplistNext(zl,eptr);
180                     redisAssert(sptr != NULL);
181 
182                     while (eptr != NULL) {
183                         redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
184                         score = zzlGetScore(sptr);
185 
186                         memset(eledigest,0,20);
187                         if (vstr != NULL) {
188                             mixDigest(eledigest,vstr,vlen);
189                         } else {
190                             ll2string(buf,sizeof(buf),vll);
191                             mixDigest(eledigest,buf,strlen(buf));
192                         }
193 
194                         snprintf(buf,sizeof(buf),"%.17g",score);
195                         mixDigest(eledigest,buf,strlen(buf));
196                         xorDigest(digest,eledigest,20);
197                         zzlNext(zl,&eptr,&sptr);
198                     }
199                 } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
200                     zset *zs = o->ptr;
201                     dictIterator *di = dictGetIterator(zs->dict);
202                     dictEntry *de;
203 
204                     while((de = dictNext(di)) != NULL) {
205                         robj *eleobj = dictGetKey(de);
206                         double *score = dictGetVal(de);
207 
208                         snprintf(buf,sizeof(buf),"%.17g",*score);
209                         memset(eledigest,0,20);
210                         mixObjectDigest(eledigest,eleobj);
211                         mixDigest(eledigest,buf,strlen(buf));
212                         xorDigest(digest,eledigest,20);
213                     }
214                     dictReleaseIterator(di);
215                 } else {
216                     redisPanic("Unknown sorted set encoding");
217                 }
218             } else if (o->type == REDIS_HASH) {
219                 hashTypeIterator *hi;
220                 robj *obj;
221 
222                 hi = hashTypeInitIterator(o);
223                 while (hashTypeNext(hi) != REDIS_ERR) {
224                     unsigned char eledigest[20];
225 
226                     memset(eledigest,0,20);
227                     obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
228                     mixObjectDigest(eledigest,obj);
229                     decrRefCount(obj);
230                     obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
231                     mixObjectDigest(eledigest,obj);
232                     decrRefCount(obj);
233                     xorDigest(digest,eledigest,20);
234                 }
235                 hashTypeReleaseIterator(hi);
236             } else {
237                 redisPanic("Unknown object type");
238             }
239             /* If the key has an expire, add it to the mix */
240             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
241             /* We can finally xor the key-val digest to the final digest */
242             xorDigest(final,digest,20);
243             decrRefCount(keyobj);
244         }
245         dictReleaseIterator(di);
246     }
247 }
248 
249 void debugCommand(redisClient *c) {
250     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
251         *((char*)-1) = 'x';
252     } else if (!strcasecmp(c->argv[1]->ptr,"oom")) {
253         void *ptr = zmalloc(ULONG_MAX); /* Should trigger an out of memory. */
254         zfree(ptr);
255         addReply(c,shared.ok);
256     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
257         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
258         redisAssertWithInfo(c,c->argv[0],1 == 2);
259     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
260         if (rdbSave(server.rdb_filename) != REDIS_OK) {
261             addReply(c,shared.err);
262             return;
263         }
264         emptyDb(NULL);
265         if (rdbLoad(server.rdb_filename) != REDIS_OK) {
266             addReplyError(c,"Error trying to load the RDB dump");
267             return;
268         }
269         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
270         addReply(c,shared.ok);
271     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
272         emptyDb(NULL);
273         if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
274             addReply(c,shared.err);
275             return;
276         }
277         server.dirty = 0; /* Prevent AOF / replication */
278         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
279         addReply(c,shared.ok);
280     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
281         dictEntry *de;
282         robj *val;
283         char *strenc;
284 
285         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
286             addReply(c,shared.nokeyerr);
287             return;
288         }
289         val = dictGetVal(de);
290         strenc = strEncoding(val->encoding);
291 
292         addReplyStatusFormat(c,
293             "Value at:%p refcount:%d "
294             "encoding:%s serializedlength:%lld "
295             "lru:%d lru_seconds_idle:%llu",
296             (void*)val, val->refcount,
297             strenc, (long long) rdbSavedObjectLen(val),
298             val->lru, estimateObjectIdleTime(val));
299     } else if (!strcasecmp(c->argv[1]->ptr,"sdslen") && c->argc == 3) {
300         dictEntry *de;
301         robj *val;
302         sds key;
303 
304         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
305             addReply(c,shared.nokeyerr);
306             return;
307         }
308         val = dictGetVal(de);
309         key = dictGetKey(de);
310 
311         if (val->type != REDIS_STRING || !sdsEncodedObject(val)) {
312             addReplyError(c,"Not an sds encoded string.");
313         } else {
314             addReplyStatusFormat(c,
315                 "key_sds_len:%lld, key_sds_avail:%lld, "
316                 "val_sds_len:%lld, val_sds_avail:%lld",
317                 (long long) sdslen(key),
318                 (long long) sdsavail(key),
319                 (long long) sdslen(val->ptr),
320                 (long long) sdsavail(val->ptr));
321         }
322     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
323         long keys, j;
324         robj *key, *val;
325         char buf[128];
326 
327         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
328             return;
329         dictExpand(c->db->dict,keys);
330         for (j = 0; j < keys; j++) {
331             snprintf(buf,sizeof(buf),"key:%lu",j);
332             key = createStringObject(buf,strlen(buf));
333             if (lookupKeyRead(c->db,key) != NULL) {
334                 decrRefCount(key);
335                 continue;
336             }
337             snprintf(buf,sizeof(buf),"value:%lu",j);
338             val = createStringObject(buf,strlen(buf));
339             dbAdd(c->db,key,val);
340             decrRefCount(key);
341         }
342         addReply(c,shared.ok);
343     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
344         unsigned char digest[20];
345         sds d = sdsempty();
346         int j;
347 
348         computeDatasetDigest(digest);
349         for (j = 0; j < 20; j++)
350             d = sdscatprintf(d, "%02x",digest[j]);
351         addReplyStatus(c,d);
352         sdsfree(d);
353     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
354         double dtime = strtod(c->argv[2]->ptr,NULL);
355         long long utime = dtime*1000000;
356         struct timespec tv;
357 
358         tv.tv_sec = utime / 1000000;
359         tv.tv_nsec = (utime % 1000000) * 1000;
360         nanosleep(&tv, NULL);
361         addReply(c,shared.ok);
362     } else if (!strcasecmp(c->argv[1]->ptr,"set-active-expire") &&
363                c->argc == 3)
364     {
365         server.active_expire_enabled = atoi(c->argv[2]->ptr);
366         addReply(c,shared.ok);
367     } else if (!strcasecmp(c->argv[1]->ptr,"cmdkeys") && c->argc >= 3) {
368         struct redisCommand *cmd = lookupCommand(c->argv[2]->ptr);
369         int *keys, numkeys, j;
370 
371         if (!cmd) {
372             addReplyError(c,"Invalid command specified");
373             return;
374         } else if ((cmd->arity > 0 && cmd->arity != c->argc-2) ||
375                    ((c->argc-2) < -cmd->arity))
376         {
377             addReplyError(c,"Invalid number of arguments specified for command");
378             return;
379         }
380 
381         keys = getKeysFromCommand(cmd,c->argv+2,c->argc-2,&numkeys);
382         addReplyMultiBulkLen(c,numkeys);
383         for (j = 0; j < numkeys; j++) addReplyBulk(c,c->argv[keys[j]+2]);
384         getKeysFreeResult(keys);
385     } else if (!strcasecmp(c->argv[1]->ptr,"error") && c->argc == 3) {
386         sds errstr = sdsnewlen("-",1);
387 
388         errstr = sdscatsds(errstr,c->argv[2]->ptr);
389         errstr = sdsmapchars(errstr,"\n\r","  ",2); /* no newlines in errors. */
390         errstr = sdscatlen(errstr,"\r\n",2);
391         addReplySds(c,errstr);
392     } else {
393         addReplyErrorFormat(c, "Unknown DEBUG subcommand or wrong number of arguments for '%s'",
394             (char*)c->argv[1]->ptr);
395     }
396 }
397 
398 /* =========================== Crash handling  ============================== */
399 
400 void _redisAssert(char *estr, char *file, int line) {
401     bugReportStart();
402     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
403     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
404 #ifdef HAVE_BACKTRACE
405     server.assert_failed = estr;
406     server.assert_file = file;
407     server.assert_line = line;
408     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
409 #endif
410     *((char*)-1) = 'x';
411 }
412 
413 void _redisAssertPrintClientInfo(redisClient *c) {
414     int j;
415 
416     bugReportStart();
417     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
418     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
419     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
420     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
421     for (j=0; j < c->argc; j++) {
422         char buf[128];
423         char *arg;
424 
425         if (c->argv[j]->type == REDIS_STRING && sdsEncodedObject(c->argv[j])) {
426             arg = (char*) c->argv[j]->ptr;
427         } else {
428             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
429                 c->argv[j]->type, c->argv[j]->encoding);
430             arg = buf;
431         }
432         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
433             j, arg, c->argv[j]->refcount);
434     }
435 }
436 
437 void redisLogObjectDebugInfo(robj *o) {
438     redisLog(REDIS_WARNING,"Object type: %d", o->type);
439     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
440     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
441     if (o->type == REDIS_STRING && sdsEncodedObject(o)) {
442         redisLog(REDIS_WARNING,"Object raw string len: %zu", sdslen(o->ptr));
443         if (sdslen(o->ptr) < 4096) {
444             sds repr = sdscatrepr(sdsempty(),o->ptr,sdslen(o->ptr));
445             redisLog(REDIS_WARNING,"Object raw string content: %s", repr);
446             sdsfree(repr);
447         }
448     } else if (o->type == REDIS_LIST) {
449         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
450     } else if (o->type == REDIS_SET) {
451         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
452     } else if (o->type == REDIS_HASH) {
453         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
454     } else if (o->type == REDIS_ZSET) {
455         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
456         if (o->encoding == REDIS_ENCODING_SKIPLIST)
457             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
458     }
459 }
460 
461 void _redisAssertPrintObject(robj *o) {
462     bugReportStart();
463     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
464     redisLogObjectDebugInfo(o);
465 }
466 
467 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
468     if (c) _redisAssertPrintClientInfo(c);
469     if (o) _redisAssertPrintObject(o);
470     _redisAssert(estr,file,line);
471 }
472 
473 void _redisPanic(char *msg, char *file, int line) {
474     bugReportStart();
475     redisLog(REDIS_WARNING,"------------------------------------------------");
476     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
477     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
478 #ifdef HAVE_BACKTRACE
479     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
480 #endif
481     redisLog(REDIS_WARNING,"------------------------------------------------");
482     *((char*)-1) = 'x';
483 }
484 
485 void bugReportStart(void) {
486     if (server.bug_report_start == 0) {
487         redisLog(REDIS_WARNING,
488             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
489         server.bug_report_start = 1;
490     }
491 }
492 
493 #ifdef HAVE_BACKTRACE
494 static void *getMcontextEip(ucontext_t *uc) {
495 #if defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
496     /* OSX < 10.6 */
497     #if defined(__x86_64__)
498     return (void*) uc->uc_mcontext->__ss.__rip;
499     #elif defined(__i386__)
500     return (void*) uc->uc_mcontext->__ss.__eip;
501     #else
502     return (void*) uc->uc_mcontext->__ss.__srr0;
503     #endif
504 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
505     /* OSX >= 10.6 */
506     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
507     return (void*) uc->uc_mcontext->__ss.__rip;
508     #else
509     return (void*) uc->uc_mcontext->__ss.__eip;
510     #endif
511 #elif defined(__linux__)
512     /* Linux */
513     #if defined(__i386__)
514     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
515     #elif defined(__X86_64__) || defined(__x86_64__)
516     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
517     #elif defined(__ia64__) /* Linux IA64 */
518     return (void*) uc->uc_mcontext.sc_ip;
519     #endif
520 #else
521     return NULL;
522 #endif
523 }
524 
525 void logStackContent(void **sp) {
526     int i;
527     for (i = 15; i >= 0; i--) {
528         unsigned long addr = (unsigned long) sp+i;
529         unsigned long val = (unsigned long) sp[i];
530 
531         if (sizeof(long) == 4)
532             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", addr, val);
533         else
534             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", addr, val);
535     }
536 }
537 
538 void logRegisters(ucontext_t *uc) {
539     redisLog(REDIS_WARNING, "--- REGISTERS");
540 
541 /* OSX */
542 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
543   /* OSX AMD64 */
544     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
545     redisLog(REDIS_WARNING,
546     "\n"
547     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
548     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
549     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
550     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
551     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
552         (unsigned long) uc->uc_mcontext->__ss.__rax,
553         (unsigned long) uc->uc_mcontext->__ss.__rbx,
554         (unsigned long) uc->uc_mcontext->__ss.__rcx,
555         (unsigned long) uc->uc_mcontext->__ss.__rdx,
556         (unsigned long) uc->uc_mcontext->__ss.__rdi,
557         (unsigned long) uc->uc_mcontext->__ss.__rsi,
558         (unsigned long) uc->uc_mcontext->__ss.__rbp,
559         (unsigned long) uc->uc_mcontext->__ss.__rsp,
560         (unsigned long) uc->uc_mcontext->__ss.__r8,
561         (unsigned long) uc->uc_mcontext->__ss.__r9,
562         (unsigned long) uc->uc_mcontext->__ss.__r10,
563         (unsigned long) uc->uc_mcontext->__ss.__r11,
564         (unsigned long) uc->uc_mcontext->__ss.__r12,
565         (unsigned long) uc->uc_mcontext->__ss.__r13,
566         (unsigned long) uc->uc_mcontext->__ss.__r14,
567         (unsigned long) uc->uc_mcontext->__ss.__r15,
568         (unsigned long) uc->uc_mcontext->__ss.__rip,
569         (unsigned long) uc->uc_mcontext->__ss.__rflags,
570         (unsigned long) uc->uc_mcontext->__ss.__cs,
571         (unsigned long) uc->uc_mcontext->__ss.__fs,
572         (unsigned long) uc->uc_mcontext->__ss.__gs
573     );
574     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
575     #else
576     /* OSX x86 */
577     redisLog(REDIS_WARNING,
578     "\n"
579     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
580     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
581     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
582     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
583         (unsigned long) uc->uc_mcontext->__ss.__eax,
584         (unsigned long) uc->uc_mcontext->__ss.__ebx,
585         (unsigned long) uc->uc_mcontext->__ss.__ecx,
586         (unsigned long) uc->uc_mcontext->__ss.__edx,
587         (unsigned long) uc->uc_mcontext->__ss.__edi,
588         (unsigned long) uc->uc_mcontext->__ss.__esi,
589         (unsigned long) uc->uc_mcontext->__ss.__ebp,
590         (unsigned long) uc->uc_mcontext->__ss.__esp,
591         (unsigned long) uc->uc_mcontext->__ss.__ss,
592         (unsigned long) uc->uc_mcontext->__ss.__eflags,
593         (unsigned long) uc->uc_mcontext->__ss.__eip,
594         (unsigned long) uc->uc_mcontext->__ss.__cs,
595         (unsigned long) uc->uc_mcontext->__ss.__ds,
596         (unsigned long) uc->uc_mcontext->__ss.__es,
597         (unsigned long) uc->uc_mcontext->__ss.__fs,
598         (unsigned long) uc->uc_mcontext->__ss.__gs
599     );
600     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
601     #endif
602 /* Linux */
603 #elif defined(__linux__)
604     /* Linux x86 */
605     #if defined(__i386__)
606     redisLog(REDIS_WARNING,
607     "\n"
608     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
609     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
610     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
611     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
612         (unsigned long) uc->uc_mcontext.gregs[11],
613         (unsigned long) uc->uc_mcontext.gregs[8],
614         (unsigned long) uc->uc_mcontext.gregs[10],
615         (unsigned long) uc->uc_mcontext.gregs[9],
616         (unsigned long) uc->uc_mcontext.gregs[4],
617         (unsigned long) uc->uc_mcontext.gregs[5],
618         (unsigned long) uc->uc_mcontext.gregs[6],
619         (unsigned long) uc->uc_mcontext.gregs[7],
620         (unsigned long) uc->uc_mcontext.gregs[18],
621         (unsigned long) uc->uc_mcontext.gregs[17],
622         (unsigned long) uc->uc_mcontext.gregs[14],
623         (unsigned long) uc->uc_mcontext.gregs[15],
624         (unsigned long) uc->uc_mcontext.gregs[3],
625         (unsigned long) uc->uc_mcontext.gregs[2],
626         (unsigned long) uc->uc_mcontext.gregs[1],
627         (unsigned long) uc->uc_mcontext.gregs[0]
628     );
629     logStackContent((void**)uc->uc_mcontext.gregs[7]);
630     #elif defined(__X86_64__) || defined(__x86_64__)
631     /* Linux AMD64 */
632     redisLog(REDIS_WARNING,
633     "\n"
634     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
635     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
636     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
637     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
638     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
639         (unsigned long) uc->uc_mcontext.gregs[13],
640         (unsigned long) uc->uc_mcontext.gregs[11],
641         (unsigned long) uc->uc_mcontext.gregs[14],
642         (unsigned long) uc->uc_mcontext.gregs[12],
643         (unsigned long) uc->uc_mcontext.gregs[8],
644         (unsigned long) uc->uc_mcontext.gregs[9],
645         (unsigned long) uc->uc_mcontext.gregs[10],
646         (unsigned long) uc->uc_mcontext.gregs[15],
647         (unsigned long) uc->uc_mcontext.gregs[0],
648         (unsigned long) uc->uc_mcontext.gregs[1],
649         (unsigned long) uc->uc_mcontext.gregs[2],
650         (unsigned long) uc->uc_mcontext.gregs[3],
651         (unsigned long) uc->uc_mcontext.gregs[4],
652         (unsigned long) uc->uc_mcontext.gregs[5],
653         (unsigned long) uc->uc_mcontext.gregs[6],
654         (unsigned long) uc->uc_mcontext.gregs[7],
655         (unsigned long) uc->uc_mcontext.gregs[16],
656         (unsigned long) uc->uc_mcontext.gregs[17],
657         (unsigned long) uc->uc_mcontext.gregs[18]
658     );
659     logStackContent((void**)uc->uc_mcontext.gregs[15]);
660     #endif
661 #else
662     redisLog(REDIS_WARNING,
663         "  Dumping of registers not supported for this OS/arch");
664 #endif
665 }
666 
667 /* Logs the stack trace using the backtrace() call. This function is designed
668  * to be called from signal handlers safely. */
669 void logStackTrace(ucontext_t *uc) {
670     void *trace[100];
671     int trace_size = 0, fd;
672     int log_to_stdout = server.logfile[0] == '\0';
673 
674     /* Open the log file in append mode. */
675     fd = log_to_stdout ?
676         STDOUT_FILENO :
677         open(server.logfile, O_APPEND|O_CREAT|O_WRONLY, 0644);
678     if (fd == -1) return;
679 
680     /* Generate the stack trace */
681     trace_size = backtrace(trace, 100);
682 
683     /* overwrite sigaction with caller's address */
684     if (getMcontextEip(uc) != NULL)
685         trace[1] = getMcontextEip(uc);
686 
687     /* Write symbols to log file */
688     backtrace_symbols_fd(trace, trace_size, fd);
689 
690     /* Cleanup */
691     if (!log_to_stdout) close(fd);
692 }
693 
694 /* Log information about the "current" client, that is, the client that is
695  * currently being served by Redis. May be NULL if Redis is not serving a
696  * client right now. */
697 void logCurrentClient(void) {
698     if (server.current_client == NULL) return;
699 
700     redisClient *cc = server.current_client;
701     sds client;
702     int j;
703 
704     redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
705     client = catClientInfoString(sdsempty(),cc);
706     redisLog(REDIS_WARNING,"client: %s", client);
707     sdsfree(client);
708     for (j = 0; j < cc->argc; j++) {
709         robj *decoded;
710 
711         decoded = getDecodedObject(cc->argv[j]);
712         redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
713         decrRefCount(decoded);
714     }
715     /* Check if the first argument, usually a key, is found inside the
716      * selected DB, and if so print info about the associated object. */
717     if (cc->argc >= 1) {
718         robj *val, *key;
719         dictEntry *de;
720 
721         key = getDecodedObject(cc->argv[1]);
722         de = dictFind(cc->db->dict, key->ptr);
723         if (de) {
724             val = dictGetVal(de);
725             redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", (char*)key->ptr);
726             redisLogObjectDebugInfo(val);
727         }
728         decrRefCount(key);
729     }
730 }
731 
732 #if defined(HAVE_PROC_MAPS)
733 void memtest_non_destructive_invert(void *addr, size_t size);
734 void memtest_non_destructive_swap(void *addr, size_t size);
735 #define MEMTEST_MAX_REGIONS 128
736 
737 int memtest_test_linux_anonymous_maps(void) {
738     FILE *fp = fopen("/proc/self/maps","r");
739     char line[1024];
740     size_t start_addr, end_addr, size;
741     size_t start_vect[MEMTEST_MAX_REGIONS];
742     size_t size_vect[MEMTEST_MAX_REGIONS];
743     int regions = 0, j;
744     uint64_t crc1 = 0, crc2 = 0, crc3 = 0;
745 
746     while(fgets(line,sizeof(line),fp) != NULL) {
747         char *start, *end, *p = line;
748 
749         start = p;
750         p = strchr(p,'-');
751         if (!p) continue;
752         *p++ = '\0';
753         end = p;
754         p = strchr(p,' ');
755         if (!p) continue;
756         *p++ = '\0';
757         if (strstr(p,"stack") ||
758             strstr(p,"vdso") ||
759             strstr(p,"vsyscall")) continue;
760         if (!strstr(p,"00:00")) continue;
761         if (!strstr(p,"rw")) continue;
762 
763         start_addr = strtoul(start,NULL,16);
764         end_addr = strtoul(end,NULL,16);
765         size = end_addr-start_addr;
766 
767         start_vect[regions] = start_addr;
768         size_vect[regions] = size;
769         printf("Testing %lx %lu\n", (unsigned long) start_vect[regions],
770                                     (unsigned long) size_vect[regions]);
771         regions++;
772     }
773 
774     /* Test all the regions as an unique sequential region.
775      * 1) Take the CRC64 of the memory region. */
776     for (j = 0; j < regions; j++) {
777         crc1 = crc64(crc1,(void*)start_vect[j],size_vect[j]);
778     }
779 
780     /* 2) Invert bits, swap adjacent words, swap again, invert bits.
781      * This is the error amplification step. */
782     for (j = 0; j < regions; j++)
783         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
784     for (j = 0; j < regions; j++)
785         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
786     for (j = 0; j < regions; j++)
787         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
788     for (j = 0; j < regions; j++)
789         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
790 
791     /* 3) Take the CRC64 sum again. */
792     for (j = 0; j < regions; j++)
793         crc2 = crc64(crc2,(void*)start_vect[j],size_vect[j]);
794 
795     /* 4) Swap + Swap again */
796     for (j = 0; j < regions; j++)
797         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
798     for (j = 0; j < regions; j++)
799         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
800 
801     /* 5) Take the CRC64 sum again. */
802     for (j = 0; j < regions; j++)
803         crc3 = crc64(crc3,(void*)start_vect[j],size_vect[j]);
804 
805     /* NOTE: It is very important to close the file descriptor only now
806      * because closing it before may result into unmapping of some memory
807      * region that we are testing. */
808     fclose(fp);
809 
810     /* If the two CRC are not the same, we trapped a memory error. */
811     return crc1 != crc2 || crc2 != crc3;
812 }
813 #endif
814 
815 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
816     ucontext_t *uc = (ucontext_t*) secret;
817     sds infostring, clients;
818     struct sigaction act;
819     REDIS_NOTUSED(info);
820 
821     bugReportStart();
822     redisLog(REDIS_WARNING,
823         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
824     redisLog(REDIS_WARNING,
825         "    Failed assertion: %s (%s:%d)", server.assert_failed,
826                         server.assert_file, server.assert_line);
827 
828     /* Log the stack trace */
829     redisLog(REDIS_WARNING, "--- STACK TRACE");
830     logStackTrace(uc);
831 
832     /* Log INFO and CLIENT LIST */
833     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
834     infostring = genRedisInfoString("all");
835     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
836         dictGetHashFunctionSeed());
837     redisLogRaw(REDIS_WARNING, infostring);
838     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
839     clients = getAllClientsInfoString();
840     redisLogRaw(REDIS_WARNING, clients);
841     sdsfree(infostring);
842     sdsfree(clients);
843 
844     /* Log the current client */
845     logCurrentClient();
846 
847     /* Log dump of processor registers */
848     logRegisters(uc);
849 
850 #if defined(HAVE_PROC_MAPS)
851     /* Test memory */
852     redisLog(REDIS_WARNING, "--- FAST MEMORY TEST");
853     bioKillThreads();
854     if (memtest_test_linux_anonymous_maps()) {
855         redisLog(REDIS_WARNING,
856             "!!! MEMORY ERROR DETECTED! Check your memory ASAP !!!");
857     } else {
858         redisLog(REDIS_WARNING,
859             "Fast memory test PASSED, however your memory can still be broken. Please run a memory test for several hours if possible.");
860     }
861 #endif
862 
863     redisLog(REDIS_WARNING,
864 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
865 "       Please report the crash opening an issue on github:\n\n"
866 "           http://github.com/antirez/redis/issues\n\n"
867 "  Suspect RAM error? Use redis-server --test-memory to veryfy it.\n\n"
868 );
869     /* free(messages); Don't call free() with possibly corrupted memory. */
870     if (server.daemonize) unlink(server.pidfile);
871 
872     /* Make sure we exit with the right signal at the end. So for instance
873      * the core will be dumped if enabled. */
874     sigemptyset (&act.sa_mask);
875     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
876     act.sa_handler = SIG_DFL;
877     sigaction (sig, &act, NULL);
878     kill(getpid(),sig);
879 }
880 #endif /* HAVE_BACKTRACE */
881 
882 /* ==================== Logging functions for debugging ===================== */
883 
884 void redisLogHexDump(int level, char *descr, void *value, size_t len) {
885     char buf[65], *b;
886     unsigned char *v = value;
887     char charset[] = "0123456789abcdef";
888 
889     redisLog(level,"%s (hexdump):", descr);
890     b = buf;
891     while(len) {
892         b[0] = charset[(*v)>>4];
893         b[1] = charset[(*v)&0xf];
894         b[2] = '\0';
895         b += 2;
896         len--;
897         v++;
898         if (b-buf == 64 || len == 0) {
899             redisLogRaw(level|REDIS_LOG_RAW,buf);
900             b = buf;
901         }
902     }
903     redisLogRaw(level|REDIS_LOG_RAW,"\n");
904 }
905 
906 /* =========================== Software Watchdog ============================ */
907 #include <sys/time.h>
908 
909 void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
910 #ifdef HAVE_BACKTRACE
911     ucontext_t *uc = (ucontext_t*) secret;
912 #endif
913     REDIS_NOTUSED(info);
914     REDIS_NOTUSED(sig);
915 
916     redisLogFromHandler(REDIS_WARNING,"\n--- WATCHDOG TIMER EXPIRED ---");
917 #ifdef HAVE_BACKTRACE
918     logStackTrace(uc);
919 #else
920     redisLogFromHandler(REDIS_WARNING,"Sorry: no support for backtrace().");
921 #endif
922     redisLogFromHandler(REDIS_WARNING,"--------\n");
923 }
924 
925 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
926  * If a timer is already scheduled, this function will re-schedule it to the
927  * specified time. If period is 0 the current timer is disabled. */
928 void watchdogScheduleSignal(int period) {
929     struct itimerval it;
930 
931     /* Will stop the timer if period is 0. */
932     it.it_value.tv_sec = period/1000;
933     it.it_value.tv_usec = (period%1000)*1000;
934     /* Don't automatically restart. */
935     it.it_interval.tv_sec = 0;
936     it.it_interval.tv_usec = 0;
937     setitimer(ITIMER_REAL, &it, NULL);
938 }
939 
940 /* Enable the software watchdog with the specified period in milliseconds. */
941 void enableWatchdog(int period) {
942     int min_period;
943 
944     if (server.watchdog_period == 0) {
945         struct sigaction act;
946 
947         /* Watchdog was actually disabled, so we have to setup the signal
948          * handler. */
949         sigemptyset(&act.sa_mask);
950         act.sa_flags = SA_ONSTACK | SA_SIGINFO;
951         act.sa_sigaction = watchdogSignalHandler;
952         sigaction(SIGALRM, &act, NULL);
953     }
954     /* If the configured period is smaller than twice the timer period, it is
955      * too short for the software watchdog to work reliably. Fix it now
956      * if needed. */
957     min_period = (1000/server.hz)*2;
958     if (period < min_period) period = min_period;
959     watchdogScheduleSignal(period); /* Adjust the current timer. */
960     server.watchdog_period = period;
961 }
962 
963 /* Disable the software watchdog. */
964 void disableWatchdog(void) {
965     struct sigaction act;
966     if (server.watchdog_period == 0) return; /* Already disabled. */
967     watchdogScheduleSignal(0); /* Stop the current timer. */
968 
969     /* Set the signal handler to SIG_IGN, this will also remove pending
970      * signals from the queue. */
971     sigemptyset(&act.sa_mask);
972     act.sa_flags = 0;
973     act.sa_handler = SIG_IGN;
974     sigaction(SIGALRM, &act, NULL);
975     server.watchdog_period = 0;
976 }
977