xref: /redis-3.2.3/src/debug.c (revision b9bb7e2d)
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,"error") && c->argc == 3) {
374         sds errstr = sdsnewlen("-",1);
375 
376         errstr = sdscatsds(errstr,c->argv[2]->ptr);
377         errstr = sdsmapchars(errstr,"\n\r","  ",2); /* no newlines in errors. */
378         errstr = sdscatlen(errstr,"\r\n",2);
379         addReplySds(c,errstr);
380     } else {
381         addReplyErrorFormat(c, "Unknown DEBUG subcommand or wrong number of arguments for '%s'",
382             (char*)c->argv[1]->ptr);
383     }
384 }
385 
386 /* =========================== Crash handling  ============================== */
387 
388 void _redisAssert(char *estr, char *file, int line) {
389     bugReportStart();
390     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
391     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
392 #ifdef HAVE_BACKTRACE
393     server.assert_failed = estr;
394     server.assert_file = file;
395     server.assert_line = line;
396     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
397 #endif
398     *((char*)-1) = 'x';
399 }
400 
401 void _redisAssertPrintClientInfo(redisClient *c) {
402     int j;
403 
404     bugReportStart();
405     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
406     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
407     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
408     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
409     for (j=0; j < c->argc; j++) {
410         char buf[128];
411         char *arg;
412 
413         if (c->argv[j]->type == REDIS_STRING && sdsEncodedObject(c->argv[j])) {
414             arg = (char*) c->argv[j]->ptr;
415         } else {
416             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
417                 c->argv[j]->type, c->argv[j]->encoding);
418             arg = buf;
419         }
420         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
421             j, arg, c->argv[j]->refcount);
422     }
423 }
424 
425 void redisLogObjectDebugInfo(robj *o) {
426     redisLog(REDIS_WARNING,"Object type: %d", o->type);
427     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
428     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
429     if (o->type == REDIS_STRING && sdsEncodedObject(o)) {
430         redisLog(REDIS_WARNING,"Object raw string len: %zu", sdslen(o->ptr));
431         if (sdslen(o->ptr) < 4096) {
432             sds repr = sdscatrepr(sdsempty(),o->ptr,sdslen(o->ptr));
433             redisLog(REDIS_WARNING,"Object raw string content: %s", repr);
434             sdsfree(repr);
435         }
436     } else if (o->type == REDIS_LIST) {
437         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
438     } else if (o->type == REDIS_SET) {
439         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
440     } else if (o->type == REDIS_HASH) {
441         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
442     } else if (o->type == REDIS_ZSET) {
443         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
444         if (o->encoding == REDIS_ENCODING_SKIPLIST)
445             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
446     }
447 }
448 
449 void _redisAssertPrintObject(robj *o) {
450     bugReportStart();
451     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
452     redisLogObjectDebugInfo(o);
453 }
454 
455 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
456     if (c) _redisAssertPrintClientInfo(c);
457     if (o) _redisAssertPrintObject(o);
458     _redisAssert(estr,file,line);
459 }
460 
461 void _redisPanic(char *msg, char *file, int line) {
462     bugReportStart();
463     redisLog(REDIS_WARNING,"------------------------------------------------");
464     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
465     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
466 #ifdef HAVE_BACKTRACE
467     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
468 #endif
469     redisLog(REDIS_WARNING,"------------------------------------------------");
470     *((char*)-1) = 'x';
471 }
472 
473 void bugReportStart(void) {
474     if (server.bug_report_start == 0) {
475         redisLog(REDIS_WARNING,
476             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
477         server.bug_report_start = 1;
478     }
479 }
480 
481 #ifdef HAVE_BACKTRACE
482 static void *getMcontextEip(ucontext_t *uc) {
483 #if defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
484     /* OSX < 10.6 */
485     #if defined(__x86_64__)
486     return (void*) uc->uc_mcontext->__ss.__rip;
487     #elif defined(__i386__)
488     return (void*) uc->uc_mcontext->__ss.__eip;
489     #else
490     return (void*) uc->uc_mcontext->__ss.__srr0;
491     #endif
492 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
493     /* OSX >= 10.6 */
494     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
495     return (void*) uc->uc_mcontext->__ss.__rip;
496     #else
497     return (void*) uc->uc_mcontext->__ss.__eip;
498     #endif
499 #elif defined(__linux__)
500     /* Linux */
501     #if defined(__i386__)
502     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
503     #elif defined(__X86_64__) || defined(__x86_64__)
504     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
505     #elif defined(__ia64__) /* Linux IA64 */
506     return (void*) uc->uc_mcontext.sc_ip;
507     #endif
508 #else
509     return NULL;
510 #endif
511 }
512 
513 void logStackContent(void **sp) {
514     int i;
515     for (i = 15; i >= 0; i--) {
516         unsigned long addr = (unsigned long) sp+i;
517         unsigned long val = (unsigned long) sp[i];
518 
519         if (sizeof(long) == 4)
520             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", addr, val);
521         else
522             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", addr, val);
523     }
524 }
525 
526 void logRegisters(ucontext_t *uc) {
527     redisLog(REDIS_WARNING, "--- REGISTERS");
528 
529 /* OSX */
530 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
531   /* OSX AMD64 */
532     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
533     redisLog(REDIS_WARNING,
534     "\n"
535     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
536     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
537     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
538     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
539     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
540         (unsigned long) uc->uc_mcontext->__ss.__rax,
541         (unsigned long) uc->uc_mcontext->__ss.__rbx,
542         (unsigned long) uc->uc_mcontext->__ss.__rcx,
543         (unsigned long) uc->uc_mcontext->__ss.__rdx,
544         (unsigned long) uc->uc_mcontext->__ss.__rdi,
545         (unsigned long) uc->uc_mcontext->__ss.__rsi,
546         (unsigned long) uc->uc_mcontext->__ss.__rbp,
547         (unsigned long) uc->uc_mcontext->__ss.__rsp,
548         (unsigned long) uc->uc_mcontext->__ss.__r8,
549         (unsigned long) uc->uc_mcontext->__ss.__r9,
550         (unsigned long) uc->uc_mcontext->__ss.__r10,
551         (unsigned long) uc->uc_mcontext->__ss.__r11,
552         (unsigned long) uc->uc_mcontext->__ss.__r12,
553         (unsigned long) uc->uc_mcontext->__ss.__r13,
554         (unsigned long) uc->uc_mcontext->__ss.__r14,
555         (unsigned long) uc->uc_mcontext->__ss.__r15,
556         (unsigned long) uc->uc_mcontext->__ss.__rip,
557         (unsigned long) uc->uc_mcontext->__ss.__rflags,
558         (unsigned long) uc->uc_mcontext->__ss.__cs,
559         (unsigned long) uc->uc_mcontext->__ss.__fs,
560         (unsigned long) uc->uc_mcontext->__ss.__gs
561     );
562     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
563     #else
564     /* OSX x86 */
565     redisLog(REDIS_WARNING,
566     "\n"
567     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
568     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
569     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
570     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
571         (unsigned long) uc->uc_mcontext->__ss.__eax,
572         (unsigned long) uc->uc_mcontext->__ss.__ebx,
573         (unsigned long) uc->uc_mcontext->__ss.__ecx,
574         (unsigned long) uc->uc_mcontext->__ss.__edx,
575         (unsigned long) uc->uc_mcontext->__ss.__edi,
576         (unsigned long) uc->uc_mcontext->__ss.__esi,
577         (unsigned long) uc->uc_mcontext->__ss.__ebp,
578         (unsigned long) uc->uc_mcontext->__ss.__esp,
579         (unsigned long) uc->uc_mcontext->__ss.__ss,
580         (unsigned long) uc->uc_mcontext->__ss.__eflags,
581         (unsigned long) uc->uc_mcontext->__ss.__eip,
582         (unsigned long) uc->uc_mcontext->__ss.__cs,
583         (unsigned long) uc->uc_mcontext->__ss.__ds,
584         (unsigned long) uc->uc_mcontext->__ss.__es,
585         (unsigned long) uc->uc_mcontext->__ss.__fs,
586         (unsigned long) uc->uc_mcontext->__ss.__gs
587     );
588     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
589     #endif
590 /* Linux */
591 #elif defined(__linux__)
592     /* Linux x86 */
593     #if defined(__i386__)
594     redisLog(REDIS_WARNING,
595     "\n"
596     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
597     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
598     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
599     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
600         (unsigned long) uc->uc_mcontext.gregs[11],
601         (unsigned long) uc->uc_mcontext.gregs[8],
602         (unsigned long) uc->uc_mcontext.gregs[10],
603         (unsigned long) uc->uc_mcontext.gregs[9],
604         (unsigned long) uc->uc_mcontext.gregs[4],
605         (unsigned long) uc->uc_mcontext.gregs[5],
606         (unsigned long) uc->uc_mcontext.gregs[6],
607         (unsigned long) uc->uc_mcontext.gregs[7],
608         (unsigned long) uc->uc_mcontext.gregs[18],
609         (unsigned long) uc->uc_mcontext.gregs[17],
610         (unsigned long) uc->uc_mcontext.gregs[14],
611         (unsigned long) uc->uc_mcontext.gregs[15],
612         (unsigned long) uc->uc_mcontext.gregs[3],
613         (unsigned long) uc->uc_mcontext.gregs[2],
614         (unsigned long) uc->uc_mcontext.gregs[1],
615         (unsigned long) uc->uc_mcontext.gregs[0]
616     );
617     logStackContent((void**)uc->uc_mcontext.gregs[7]);
618     #elif defined(__X86_64__) || defined(__x86_64__)
619     /* Linux AMD64 */
620     redisLog(REDIS_WARNING,
621     "\n"
622     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
623     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
624     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
625     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
626     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
627         (unsigned long) uc->uc_mcontext.gregs[13],
628         (unsigned long) uc->uc_mcontext.gregs[11],
629         (unsigned long) uc->uc_mcontext.gregs[14],
630         (unsigned long) uc->uc_mcontext.gregs[12],
631         (unsigned long) uc->uc_mcontext.gregs[8],
632         (unsigned long) uc->uc_mcontext.gregs[9],
633         (unsigned long) uc->uc_mcontext.gregs[10],
634         (unsigned long) uc->uc_mcontext.gregs[15],
635         (unsigned long) uc->uc_mcontext.gregs[0],
636         (unsigned long) uc->uc_mcontext.gregs[1],
637         (unsigned long) uc->uc_mcontext.gregs[2],
638         (unsigned long) uc->uc_mcontext.gregs[3],
639         (unsigned long) uc->uc_mcontext.gregs[4],
640         (unsigned long) uc->uc_mcontext.gregs[5],
641         (unsigned long) uc->uc_mcontext.gregs[6],
642         (unsigned long) uc->uc_mcontext.gregs[7],
643         (unsigned long) uc->uc_mcontext.gregs[16],
644         (unsigned long) uc->uc_mcontext.gregs[17],
645         (unsigned long) uc->uc_mcontext.gregs[18]
646     );
647     logStackContent((void**)uc->uc_mcontext.gregs[15]);
648     #endif
649 #else
650     redisLog(REDIS_WARNING,
651         "  Dumping of registers not supported for this OS/arch");
652 #endif
653 }
654 
655 /* Logs the stack trace using the backtrace() call. This function is designed
656  * to be called from signal handlers safely. */
657 void logStackTrace(ucontext_t *uc) {
658     void *trace[100];
659     int trace_size = 0, fd;
660     int log_to_stdout = server.logfile[0] == '\0';
661 
662     /* Open the log file in append mode. */
663     fd = log_to_stdout ?
664         STDOUT_FILENO :
665         open(server.logfile, O_APPEND|O_CREAT|O_WRONLY, 0644);
666     if (fd == -1) return;
667 
668     /* Generate the stack trace */
669     trace_size = backtrace(trace, 100);
670 
671     /* overwrite sigaction with caller's address */
672     if (getMcontextEip(uc) != NULL)
673         trace[1] = getMcontextEip(uc);
674 
675     /* Write symbols to log file */
676     backtrace_symbols_fd(trace, trace_size, fd);
677 
678     /* Cleanup */
679     if (!log_to_stdout) close(fd);
680 }
681 
682 /* Log information about the "current" client, that is, the client that is
683  * currently being served by Redis. May be NULL if Redis is not serving a
684  * client right now. */
685 void logCurrentClient(void) {
686     if (server.current_client == NULL) return;
687 
688     redisClient *cc = server.current_client;
689     sds client;
690     int j;
691 
692     redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
693     client = catClientInfoString(sdsempty(),cc);
694     redisLog(REDIS_WARNING,"client: %s", client);
695     sdsfree(client);
696     for (j = 0; j < cc->argc; j++) {
697         robj *decoded;
698 
699         decoded = getDecodedObject(cc->argv[j]);
700         redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
701         decrRefCount(decoded);
702     }
703     /* Check if the first argument, usually a key, is found inside the
704      * selected DB, and if so print info about the associated object. */
705     if (cc->argc >= 1) {
706         robj *val, *key;
707         dictEntry *de;
708 
709         key = getDecodedObject(cc->argv[1]);
710         de = dictFind(cc->db->dict, key->ptr);
711         if (de) {
712             val = dictGetVal(de);
713             redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", (char*)key->ptr);
714             redisLogObjectDebugInfo(val);
715         }
716         decrRefCount(key);
717     }
718 }
719 
720 #if defined(HAVE_PROC_MAPS)
721 void memtest_non_destructive_invert(void *addr, size_t size);
722 void memtest_non_destructive_swap(void *addr, size_t size);
723 #define MEMTEST_MAX_REGIONS 128
724 
725 int memtest_test_linux_anonymous_maps(void) {
726     FILE *fp = fopen("/proc/self/maps","r");
727     char line[1024];
728     size_t start_addr, end_addr, size;
729     size_t start_vect[MEMTEST_MAX_REGIONS];
730     size_t size_vect[MEMTEST_MAX_REGIONS];
731     int regions = 0, j;
732     uint64_t crc1 = 0, crc2 = 0, crc3 = 0;
733 
734     while(fgets(line,sizeof(line),fp) != NULL) {
735         char *start, *end, *p = line;
736 
737         start = p;
738         p = strchr(p,'-');
739         if (!p) continue;
740         *p++ = '\0';
741         end = p;
742         p = strchr(p,' ');
743         if (!p) continue;
744         *p++ = '\0';
745         if (strstr(p,"stack") ||
746             strstr(p,"vdso") ||
747             strstr(p,"vsyscall")) continue;
748         if (!strstr(p,"00:00")) continue;
749         if (!strstr(p,"rw")) continue;
750 
751         start_addr = strtoul(start,NULL,16);
752         end_addr = strtoul(end,NULL,16);
753         size = end_addr-start_addr;
754 
755         start_vect[regions] = start_addr;
756         size_vect[regions] = size;
757         printf("Testing %lx %lu\n", (unsigned long) start_vect[regions],
758                                     (unsigned long) size_vect[regions]);
759         regions++;
760     }
761 
762     /* Test all the regions as an unique sequential region.
763      * 1) Take the CRC64 of the memory region. */
764     for (j = 0; j < regions; j++) {
765         crc1 = crc64(crc1,(void*)start_vect[j],size_vect[j]);
766     }
767 
768     /* 2) Invert bits, swap adjacent words, swap again, invert bits.
769      * This is the error amplification step. */
770     for (j = 0; j < regions; j++)
771         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
772     for (j = 0; j < regions; j++)
773         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
774     for (j = 0; j < regions; j++)
775         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
776     for (j = 0; j < regions; j++)
777         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
778 
779     /* 3) Take the CRC64 sum again. */
780     for (j = 0; j < regions; j++)
781         crc2 = crc64(crc2,(void*)start_vect[j],size_vect[j]);
782 
783     /* 4) Swap + Swap again */
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 
789     /* 5) Take the CRC64 sum again. */
790     for (j = 0; j < regions; j++)
791         crc3 = crc64(crc3,(void*)start_vect[j],size_vect[j]);
792 
793     /* NOTE: It is very important to close the file descriptor only now
794      * because closing it before may result into unmapping of some memory
795      * region that we are testing. */
796     fclose(fp);
797 
798     /* If the two CRC are not the same, we trapped a memory error. */
799     return crc1 != crc2 || crc2 != crc3;
800 }
801 #endif
802 
803 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
804     ucontext_t *uc = (ucontext_t*) secret;
805     sds infostring, clients;
806     struct sigaction act;
807     REDIS_NOTUSED(info);
808 
809     bugReportStart();
810     redisLog(REDIS_WARNING,
811         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
812     redisLog(REDIS_WARNING,
813         "    Failed assertion: %s (%s:%d)", server.assert_failed,
814                         server.assert_file, server.assert_line);
815 
816     /* Log the stack trace */
817     redisLog(REDIS_WARNING, "--- STACK TRACE");
818     logStackTrace(uc);
819 
820     /* Log INFO and CLIENT LIST */
821     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
822     infostring = genRedisInfoString("all");
823     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
824         dictGetHashFunctionSeed());
825     redisLogRaw(REDIS_WARNING, infostring);
826     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
827     clients = getAllClientsInfoString();
828     redisLogRaw(REDIS_WARNING, clients);
829     sdsfree(infostring);
830     sdsfree(clients);
831 
832     /* Log the current client */
833     logCurrentClient();
834 
835     /* Log dump of processor registers */
836     logRegisters(uc);
837 
838 #if defined(HAVE_PROC_MAPS)
839     /* Test memory */
840     redisLog(REDIS_WARNING, "--- FAST MEMORY TEST");
841     bioKillThreads();
842     if (memtest_test_linux_anonymous_maps()) {
843         redisLog(REDIS_WARNING,
844             "!!! MEMORY ERROR DETECTED! Check your memory ASAP !!!");
845     } else {
846         redisLog(REDIS_WARNING,
847             "Fast memory test PASSED, however your memory can still be broken. Please run a memory test for several hours if possible.");
848     }
849 #endif
850 
851     redisLog(REDIS_WARNING,
852 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
853 "       Please report the crash opening an issue on github:\n\n"
854 "           http://github.com/antirez/redis/issues\n\n"
855 "  Suspect RAM error? Use redis-server --test-memory to verify it.\n\n"
856 );
857     /* free(messages); Don't call free() with possibly corrupted memory. */
858     if (server.daemonize) unlink(server.pidfile);
859 
860     /* Make sure we exit with the right signal at the end. So for instance
861      * the core will be dumped if enabled. */
862     sigemptyset (&act.sa_mask);
863     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
864     act.sa_handler = SIG_DFL;
865     sigaction (sig, &act, NULL);
866     kill(getpid(),sig);
867 }
868 #endif /* HAVE_BACKTRACE */
869 
870 /* ==================== Logging functions for debugging ===================== */
871 
872 void redisLogHexDump(int level, char *descr, void *value, size_t len) {
873     char buf[65], *b;
874     unsigned char *v = value;
875     char charset[] = "0123456789abcdef";
876 
877     redisLog(level,"%s (hexdump):", descr);
878     b = buf;
879     while(len) {
880         b[0] = charset[(*v)>>4];
881         b[1] = charset[(*v)&0xf];
882         b[2] = '\0';
883         b += 2;
884         len--;
885         v++;
886         if (b-buf == 64 || len == 0) {
887             redisLogRaw(level|REDIS_LOG_RAW,buf);
888             b = buf;
889         }
890     }
891     redisLogRaw(level|REDIS_LOG_RAW,"\n");
892 }
893 
894 /* =========================== Software Watchdog ============================ */
895 #include <sys/time.h>
896 
897 void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
898 #ifdef HAVE_BACKTRACE
899     ucontext_t *uc = (ucontext_t*) secret;
900 #endif
901     REDIS_NOTUSED(info);
902     REDIS_NOTUSED(sig);
903 
904     redisLogFromHandler(REDIS_WARNING,"\n--- WATCHDOG TIMER EXPIRED ---");
905 #ifdef HAVE_BACKTRACE
906     logStackTrace(uc);
907 #else
908     redisLogFromHandler(REDIS_WARNING,"Sorry: no support for backtrace().");
909 #endif
910     redisLogFromHandler(REDIS_WARNING,"--------\n");
911 }
912 
913 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
914  * If a timer is already scheduled, this function will re-schedule it to the
915  * specified time. If period is 0 the current timer is disabled. */
916 void watchdogScheduleSignal(int period) {
917     struct itimerval it;
918 
919     /* Will stop the timer if period is 0. */
920     it.it_value.tv_sec = period/1000;
921     it.it_value.tv_usec = (period%1000)*1000;
922     /* Don't automatically restart. */
923     it.it_interval.tv_sec = 0;
924     it.it_interval.tv_usec = 0;
925     setitimer(ITIMER_REAL, &it, NULL);
926 }
927 
928 /* Enable the software watchdog with the specified period in milliseconds. */
929 void enableWatchdog(int period) {
930     int min_period;
931 
932     if (server.watchdog_period == 0) {
933         struct sigaction act;
934 
935         /* Watchdog was actually disabled, so we have to setup the signal
936          * handler. */
937         sigemptyset(&act.sa_mask);
938         act.sa_flags = SA_ONSTACK | SA_SIGINFO;
939         act.sa_sigaction = watchdogSignalHandler;
940         sigaction(SIGALRM, &act, NULL);
941     }
942     /* If the configured period is smaller than twice the timer period, it is
943      * too short for the software watchdog to work reliably. Fix it now
944      * if needed. */
945     min_period = (1000/server.hz)*2;
946     if (period < min_period) period = min_period;
947     watchdogScheduleSignal(period); /* Adjust the current timer. */
948     server.watchdog_period = period;
949 }
950 
951 /* Disable the software watchdog. */
952 void disableWatchdog(void) {
953     struct sigaction act;
954     if (server.watchdog_period == 0) return; /* Already disabled. */
955     watchdogScheduleSignal(0); /* Stop the current timer. */
956 
957     /* Set the signal handler to SIG_IGN, this will also remove pending
958      * signals from the queue. */
959     sigemptyset(&act.sa_mask);
960     act.sa_flags = 0;
961     act.sa_handler = SIG_IGN;
962     sigaction(SIGALRM, &act, NULL);
963     server.watchdog_period = 0;
964 }
965