xref: /redis-3.2.3/src/debug.c (revision 2f75bbab)
1 #include "redis.h"
2 #include "sha1.h"   /* SHA1 is used for DEBUG DIGEST */
3 
4 #include <arpa/inet.h>
5 #include <signal.h>
6 
7 #ifdef HAVE_BACKTRACE
8 #include <execinfo.h>
9 #include <ucontext.h>
10 #endif /* HAVE_BACKTRACE */
11 
12 /* ================================= Debugging ============================== */
13 
14 /* Compute the sha1 of string at 's' with 'len' bytes long.
15  * The SHA1 is then xored againt the string pointed by digest.
16  * Since xor is commutative, this operation is used in order to
17  * "add" digests relative to unordered elements.
18  *
19  * So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
20 void xorDigest(unsigned char *digest, void *ptr, size_t len) {
21     SHA1_CTX ctx;
22     unsigned char hash[20], *s = ptr;
23     int j;
24 
25     SHA1Init(&ctx);
26     SHA1Update(&ctx,s,len);
27     SHA1Final(hash,&ctx);
28 
29     for (j = 0; j < 20; j++)
30         digest[j] ^= hash[j];
31 }
32 
33 void xorObjectDigest(unsigned char *digest, robj *o) {
34     o = getDecodedObject(o);
35     xorDigest(digest,o->ptr,sdslen(o->ptr));
36     decrRefCount(o);
37 }
38 
39 /* This function instead of just computing the SHA1 and xoring it
40  * against diget, also perform the digest of "digest" itself and
41  * replace the old value with the new one.
42  *
43  * So the final digest will be:
44  *
45  * digest = SHA1(digest xor SHA1(data))
46  *
47  * This function is used every time we want to preserve the order so
48  * that digest(a,b,c,d) will be different than digest(b,c,d,a)
49  *
50  * Also note that mixdigest("foo") followed by mixdigest("bar")
51  * will lead to a different digest compared to "fo", "obar".
52  */
53 void mixDigest(unsigned char *digest, void *ptr, size_t len) {
54     SHA1_CTX ctx;
55     char *s = ptr;
56 
57     xorDigest(digest,s,len);
58     SHA1Init(&ctx);
59     SHA1Update(&ctx,digest,20);
60     SHA1Final(digest,&ctx);
61 }
62 
63 void mixObjectDigest(unsigned char *digest, robj *o) {
64     o = getDecodedObject(o);
65     mixDigest(digest,o->ptr,sdslen(o->ptr));
66     decrRefCount(o);
67 }
68 
69 /* Compute the dataset digest. Since keys, sets elements, hashes elements
70  * are not ordered, we use a trick: every aggregate digest is the xor
71  * of the digests of their elements. This way the order will not change
72  * the result. For list instead we use a feedback entering the output digest
73  * as input in order to ensure that a different ordered list will result in
74  * a different digest. */
75 void computeDatasetDigest(unsigned char *final) {
76     unsigned char digest[20];
77     char buf[128];
78     dictIterator *di = NULL;
79     dictEntry *de;
80     int j;
81     uint32_t aux;
82 
83     memset(final,0,20); /* Start with a clean result */
84 
85     for (j = 0; j < server.dbnum; j++) {
86         redisDb *db = server.db+j;
87 
88         if (dictSize(db->dict) == 0) continue;
89         di = dictGetIterator(db->dict);
90 
91         /* hash the DB id, so the same dataset moved in a different
92          * DB will lead to a different digest */
93         aux = htonl(j);
94         mixDigest(final,&aux,sizeof(aux));
95 
96         /* Iterate this DB writing every entry */
97         while((de = dictNext(di)) != NULL) {
98             sds key;
99             robj *keyobj, *o;
100             long long expiretime;
101 
102             memset(digest,0,20); /* This key-val digest */
103             key = dictGetKey(de);
104             keyobj = createStringObject(key,sdslen(key));
105 
106             mixDigest(digest,key,sdslen(key));
107 
108             /* Make sure the key is loaded if VM is active */
109             o = dictGetVal(de);
110 
111             aux = htonl(o->type);
112             mixDigest(digest,&aux,sizeof(aux));
113             expiretime = getExpire(db,keyobj);
114 
115             /* Save the key and associated value */
116             if (o->type == REDIS_STRING) {
117                 mixObjectDigest(digest,o);
118             } else if (o->type == REDIS_LIST) {
119                 listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
120                 listTypeEntry entry;
121                 while(listTypeNext(li,&entry)) {
122                     robj *eleobj = listTypeGet(&entry);
123                     mixObjectDigest(digest,eleobj);
124                     decrRefCount(eleobj);
125                 }
126                 listTypeReleaseIterator(li);
127             } else if (o->type == REDIS_SET) {
128                 setTypeIterator *si = setTypeInitIterator(o);
129                 robj *ele;
130                 while((ele = setTypeNextObject(si)) != NULL) {
131                     xorObjectDigest(digest,ele);
132                     decrRefCount(ele);
133                 }
134                 setTypeReleaseIterator(si);
135             } else if (o->type == REDIS_ZSET) {
136                 unsigned char eledigest[20];
137 
138                 if (o->encoding == REDIS_ENCODING_ZIPLIST) {
139                     unsigned char *zl = o->ptr;
140                     unsigned char *eptr, *sptr;
141                     unsigned char *vstr;
142                     unsigned int vlen;
143                     long long vll;
144                     double score;
145 
146                     eptr = ziplistIndex(zl,0);
147                     redisAssert(eptr != NULL);
148                     sptr = ziplistNext(zl,eptr);
149                     redisAssert(sptr != NULL);
150 
151                     while (eptr != NULL) {
152                         redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
153                         score = zzlGetScore(sptr);
154 
155                         memset(eledigest,0,20);
156                         if (vstr != NULL) {
157                             mixDigest(eledigest,vstr,vlen);
158                         } else {
159                             ll2string(buf,sizeof(buf),vll);
160                             mixDigest(eledigest,buf,strlen(buf));
161                         }
162 
163                         snprintf(buf,sizeof(buf),"%.17g",score);
164                         mixDigest(eledigest,buf,strlen(buf));
165                         xorDigest(digest,eledigest,20);
166                         zzlNext(zl,&eptr,&sptr);
167                     }
168                 } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
169                     zset *zs = o->ptr;
170                     dictIterator *di = dictGetIterator(zs->dict);
171                     dictEntry *de;
172 
173                     while((de = dictNext(di)) != NULL) {
174                         robj *eleobj = dictGetKey(de);
175                         double *score = dictGetVal(de);
176 
177                         snprintf(buf,sizeof(buf),"%.17g",*score);
178                         memset(eledigest,0,20);
179                         mixObjectDigest(eledigest,eleobj);
180                         mixDigest(eledigest,buf,strlen(buf));
181                         xorDigest(digest,eledigest,20);
182                     }
183                     dictReleaseIterator(di);
184                 } else {
185                     redisPanic("Unknown sorted set encoding");
186                 }
187             } else if (o->type == REDIS_HASH) {
188                 hashTypeIterator *hi;
189                 robj *obj;
190 
191                 hi = hashTypeInitIterator(o);
192                 while (hashTypeNext(hi) != REDIS_ERR) {
193                     unsigned char eledigest[20];
194 
195                     memset(eledigest,0,20);
196                     obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
197                     mixObjectDigest(eledigest,obj);
198                     decrRefCount(obj);
199                     obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
200                     mixObjectDigest(eledigest,obj);
201                     decrRefCount(obj);
202                     xorDigest(digest,eledigest,20);
203                 }
204                 hashTypeReleaseIterator(hi);
205             } else {
206                 redisPanic("Unknown object type");
207             }
208             /* If the key has an expire, add it to the mix */
209             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
210             /* We can finally xor the key-val digest to the final digest */
211             xorDigest(final,digest,20);
212             decrRefCount(keyobj);
213         }
214         dictReleaseIterator(di);
215     }
216 }
217 
218 void debugCommand(redisClient *c) {
219     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
220         *((char*)-1) = 'x';
221     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
222         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
223         redisAssertWithInfo(c,c->argv[0],1 == 2);
224     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
225         if (rdbSave(server.rdb_filename) != REDIS_OK) {
226             addReply(c,shared.err);
227             return;
228         }
229         emptyDb();
230         if (rdbLoad(server.rdb_filename) != REDIS_OK) {
231             addReplyError(c,"Error trying to load the RDB dump");
232             return;
233         }
234         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
235         addReply(c,shared.ok);
236     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
237         emptyDb();
238         if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
239             addReply(c,shared.err);
240             return;
241         }
242         server.dirty = 0; /* Prevent AOF / replication */
243         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
244         addReply(c,shared.ok);
245     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
246         dictEntry *de;
247         robj *val;
248         char *strenc;
249 
250         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
251             addReply(c,shared.nokeyerr);
252             return;
253         }
254         val = dictGetVal(de);
255         strenc = strEncoding(val->encoding);
256 
257         addReplyStatusFormat(c,
258             "Value at:%p refcount:%d "
259             "encoding:%s serializedlength:%lld "
260             "lru:%d lru_seconds_idle:%lu",
261             (void*)val, val->refcount,
262             strenc, (long long) rdbSavedObjectLen(val),
263             val->lru, estimateObjectIdleTime(val));
264     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
265         long keys, j;
266         robj *key, *val;
267         char buf[128];
268 
269         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
270             return;
271         for (j = 0; j < keys; j++) {
272             snprintf(buf,sizeof(buf),"key:%lu",j);
273             key = createStringObject(buf,strlen(buf));
274             if (lookupKeyRead(c->db,key) != NULL) {
275                 decrRefCount(key);
276                 continue;
277             }
278             snprintf(buf,sizeof(buf),"value:%lu",j);
279             val = createStringObject(buf,strlen(buf));
280             dbAdd(c->db,key,val);
281             decrRefCount(key);
282         }
283         addReply(c,shared.ok);
284     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
285         unsigned char digest[20];
286         sds d = sdsempty();
287         int j;
288 
289         computeDatasetDigest(digest);
290         for (j = 0; j < 20; j++)
291             d = sdscatprintf(d, "%02x",digest[j]);
292         addReplyStatus(c,d);
293         sdsfree(d);
294     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
295         double dtime = strtod(c->argv[2]->ptr,NULL);
296         long long utime = dtime*1000000;
297 
298         usleep(utime);
299         addReply(c,shared.ok);
300     } else {
301         addReplyError(c,
302             "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
303     }
304 }
305 
306 /* =========================== Crash handling  ============================== */
307 
308 void _redisAssert(char *estr, char *file, int line) {
309     bugReportStart();
310     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
311     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
312 #ifdef HAVE_BACKTRACE
313     server.assert_failed = estr;
314     server.assert_file = file;
315     server.assert_line = line;
316     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
317     *((char*)-1) = 'x';
318 #endif
319 }
320 
321 void _redisAssertPrintClientInfo(redisClient *c) {
322     int j;
323 
324     bugReportStart();
325     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
326     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
327     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
328     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
329     for (j=0; j < c->argc; j++) {
330         char buf[128];
331         char *arg;
332 
333         if (c->argv[j]->type == REDIS_STRING &&
334             c->argv[j]->encoding == REDIS_ENCODING_RAW)
335         {
336             arg = (char*) c->argv[j]->ptr;
337         } else {
338             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
339                 c->argv[j]->type, c->argv[j]->encoding);
340             arg = buf;
341         }
342         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
343             j, arg, c->argv[j]->refcount);
344     }
345 }
346 
347 void redisLogObjectDebugInfo(robj *o) {
348     redisLog(REDIS_WARNING,"Object type: %d", o->type);
349     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
350     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
351     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
352         redisLog(REDIS_WARNING,"Object raw string len: %d", sdslen(o->ptr));
353         if (sdslen(o->ptr) < 4096)
354             redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
355     } else if (o->type == REDIS_LIST) {
356         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
357     } else if (o->type == REDIS_SET) {
358         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
359     } else if (o->type == REDIS_HASH) {
360         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
361     } else if (o->type == REDIS_ZSET) {
362         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
363         if (o->encoding == REDIS_ENCODING_SKIPLIST)
364             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
365     }
366 }
367 
368 void _redisAssertPrintObject(robj *o) {
369     bugReportStart();
370     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
371     redisLogObjectDebugInfo(o);
372 }
373 
374 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
375     if (c) _redisAssertPrintClientInfo(c);
376     if (o) _redisAssertPrintObject(o);
377     _redisAssert(estr,file,line);
378 }
379 
380 void _redisPanic(char *msg, char *file, int line) {
381     bugReportStart();
382     redisLog(REDIS_WARNING,"------------------------------------------------");
383     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
384     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
385 #ifdef HAVE_BACKTRACE
386     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
387     redisLog(REDIS_WARNING,"------------------------------------------------");
388     *((char*)-1) = 'x';
389 #endif
390 }
391 
392 #ifdef HAVE_BACKTRACE
393 static void *getMcontextEip(ucontext_t *uc) {
394 #if defined(__FreeBSD__)
395     return (void*) uc->uc_mcontext.mc_eip;
396 #elif defined(__dietlibc__)
397     return (void*) uc->uc_mcontext.eip;
398 #elif defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
399   #if __x86_64__
400     return (void*) uc->uc_mcontext->__ss.__rip;
401   #elif __i386__
402     return (void*) uc->uc_mcontext->__ss.__eip;
403   #else
404     return (void*) uc->uc_mcontext->__ss.__srr0;
405   #endif
406 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
407   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
408     return (void*) uc->uc_mcontext->__ss.__rip;
409   #else
410     return (void*) uc->uc_mcontext->__ss.__eip;
411   #endif
412 #elif defined(__i386__)
413     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
414 #elif defined(__X86_64__) || defined(__x86_64__)
415     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
416 #elif defined(__ia64__) /* Linux IA64 */
417     return (void*) uc->uc_mcontext.sc_ip;
418 #else
419     return NULL;
420 #endif
421 }
422 
423 void bugReportStart(void) {
424     if (server.bug_report_start == 0) {
425         redisLog(REDIS_WARNING,
426             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
427         server.bug_report_start = 1;
428     }
429 }
430 
431 void logStackContent(void **sp) {
432     int i;
433     for (i = 15; i >= 0; i--) {
434         if (sizeof(long) == 4)
435             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", sp+i, sp[i]);
436         else
437             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", sp+i, sp[i]);
438     }
439 }
440 
441 void logRegisters(ucontext_t *uc) {
442     redisLog(REDIS_WARNING, "--- REGISTERS");
443 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
444   #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
445     redisLog(REDIS_WARNING,
446     "\n"
447     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
448     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
449     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
450     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
451     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
452         uc->uc_mcontext->__ss.__rax,
453         uc->uc_mcontext->__ss.__rbx,
454         uc->uc_mcontext->__ss.__rcx,
455         uc->uc_mcontext->__ss.__rdx,
456         uc->uc_mcontext->__ss.__rdi,
457         uc->uc_mcontext->__ss.__rsi,
458         uc->uc_mcontext->__ss.__rbp,
459         uc->uc_mcontext->__ss.__rsp,
460         uc->uc_mcontext->__ss.__r8,
461         uc->uc_mcontext->__ss.__r9,
462         uc->uc_mcontext->__ss.__r10,
463         uc->uc_mcontext->__ss.__r11,
464         uc->uc_mcontext->__ss.__r12,
465         uc->uc_mcontext->__ss.__r13,
466         uc->uc_mcontext->__ss.__r14,
467         uc->uc_mcontext->__ss.__r15,
468         uc->uc_mcontext->__ss.__rip,
469         uc->uc_mcontext->__ss.__rflags,
470         uc->uc_mcontext->__ss.__cs,
471         uc->uc_mcontext->__ss.__fs,
472         uc->uc_mcontext->__ss.__gs
473     );
474     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
475   #else
476     redisLog(REDIS_WARNING,
477     "\n"
478     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
479     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
480     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
481     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
482         uc->uc_mcontext->__ss.__eax,
483         uc->uc_mcontext->__ss.__ebx,
484         uc->uc_mcontext->__ss.__ecx,
485         uc->uc_mcontext->__ss.__edx,
486         uc->uc_mcontext->__ss.__edi,
487         uc->uc_mcontext->__ss.__esi,
488         uc->uc_mcontext->__ss.__ebp,
489         uc->uc_mcontext->__ss.__esp,
490         uc->uc_mcontext->__ss.__ss,
491         uc->uc_mcontext->__ss.__eflags,
492         uc->uc_mcontext->__ss.__eip,
493         uc->uc_mcontext->__ss.__cs,
494         uc->uc_mcontext->__ss.__ds,
495         uc->uc_mcontext->__ss.__es,
496         uc->uc_mcontext->__ss.__fs,
497         uc->uc_mcontext->__ss.__gs
498     );
499     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
500   #endif
501 #elif defined(__i386__)
502     redisLog(REDIS_WARNING,
503     "\n"
504     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
505     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
506     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
507     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
508         uc->uc_mcontext.gregs[11],
509         uc->uc_mcontext.gregs[8],
510         uc->uc_mcontext.gregs[10],
511         uc->uc_mcontext.gregs[9],
512         uc->uc_mcontext.gregs[4],
513         uc->uc_mcontext.gregs[5],
514         uc->uc_mcontext.gregs[6],
515         uc->uc_mcontext.gregs[7],
516         uc->uc_mcontext.gregs[18],
517         uc->uc_mcontext.gregs[17],
518         uc->uc_mcontext.gregs[14],
519         uc->uc_mcontext.gregs[15],
520         uc->uc_mcontext.gregs[3],
521         uc->uc_mcontext.gregs[2],
522         uc->uc_mcontext.gregs[1],
523         uc->uc_mcontext.gregs[0]
524     );
525     logStackContent((void**)uc->uc_mcontext.gregs[7]);
526 #elif defined(__X86_64__) || defined(__x86_64__)
527     redisLog(REDIS_WARNING,
528     "\n"
529     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
530     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
531     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
532     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
533     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
534         uc->uc_mcontext.gregs[13],
535         uc->uc_mcontext.gregs[11],
536         uc->uc_mcontext.gregs[14],
537         uc->uc_mcontext.gregs[12],
538         uc->uc_mcontext.gregs[8],
539         uc->uc_mcontext.gregs[9],
540         uc->uc_mcontext.gregs[10],
541         uc->uc_mcontext.gregs[15],
542         uc->uc_mcontext.gregs[0],
543         uc->uc_mcontext.gregs[1],
544         uc->uc_mcontext.gregs[2],
545         uc->uc_mcontext.gregs[3],
546         uc->uc_mcontext.gregs[4],
547         uc->uc_mcontext.gregs[5],
548         uc->uc_mcontext.gregs[6],
549         uc->uc_mcontext.gregs[7],
550         uc->uc_mcontext.gregs[16],
551         uc->uc_mcontext.gregs[17],
552         uc->uc_mcontext.gregs[18]
553     );
554     logStackContent((void**)uc->uc_mcontext.gregs[15]);
555 #else
556     redisLog(REDIS_WARNING,
557         "  Dumping of registers not supported for this OS/arch");
558 #endif
559 }
560 
561 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
562     void *trace[100];
563     char **messages = NULL;
564     int i, trace_size = 0;
565     ucontext_t *uc = (ucontext_t*) secret;
566     sds infostring, clients;
567     struct sigaction act;
568     REDIS_NOTUSED(info);
569 
570     bugReportStart();
571     redisLog(REDIS_WARNING,
572         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
573     redisLog(REDIS_WARNING,
574         "    Failed assertion: %s (%s:%d)", server.assert_failed,
575                         server.assert_file, server.assert_line);
576 
577     /* Generate the stack trace */
578     trace_size = backtrace(trace, 100);
579 
580     /* overwrite sigaction with caller's address */
581     if (getMcontextEip(uc) != NULL) {
582         trace[1] = getMcontextEip(uc);
583     }
584     messages = backtrace_symbols(trace, trace_size);
585     redisLog(REDIS_WARNING, "--- STACK TRACE");
586     for (i=1; i<trace_size; ++i)
587         redisLog(REDIS_WARNING,"%s", messages[i]);
588 
589     /* Log INFO and CLIENT LIST */
590     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
591     infostring = genRedisInfoString("all");
592     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
593         dictGetHashFunctionSeed());
594     redisLogRaw(REDIS_WARNING, infostring);
595     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
596     clients = getAllClientsInfoString();
597     redisLogRaw(REDIS_WARNING, clients);
598     /* Don't sdsfree() strings to avoid a crash. Memory may be corrupted. */
599 
600     /* Log CURRENT CLIENT info */
601     if (server.current_client) {
602         redisClient *cc = server.current_client;
603         sds client;
604         int j;
605 
606         redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
607         client = getClientInfoString(cc);
608         redisLog(REDIS_WARNING,"client: %s", client);
609         /* Missing sdsfree(client) to avoid crash if memory is corrupted. */
610         for (j = 0; j < cc->argc; j++) {
611             robj *decoded;
612 
613             decoded = getDecodedObject(cc->argv[j]);
614             redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
615             decrRefCount(decoded);
616         }
617         /* Check if the first argument, usually a key, is found inside the
618          * selected DB, and if so print info about the associated object. */
619         if (cc->argc >= 1) {
620             robj *val, *key;
621             dictEntry *de;
622 
623             key = getDecodedObject(cc->argv[1]);
624             de = dictFind(cc->db->dict, key->ptr);
625             if (de) {
626                 val = dictGetVal(de);
627                 redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
628                 redisLogObjectDebugInfo(val);
629             }
630             decrRefCount(key);
631         }
632     }
633 
634     /* Log dump of processor registers */
635     logRegisters(uc);
636 
637     redisLog(REDIS_WARNING,
638 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
639 "    Please report the crash opening an issue on github:\n\n"
640 "        http://github.com/antirez/redis/issues\n\n"
641 );
642     /* free(messages); Don't call free() with possibly corrupted memory. */
643     if (server.daemonize) unlink(server.pidfile);
644 
645     /* Make sure we exit with the right signal at the end. So for instance
646      * the core will be dumped if enabled. */
647     sigemptyset (&act.sa_mask);
648     /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
649      * is used. Otherwise, sa_handler is used */
650     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
651     act.sa_handler = SIG_DFL;
652     sigaction (sig, &act, NULL);
653     kill(getpid(),sig);
654 }
655 #endif /* HAVE_BACKTRACE */
656