xref: /redis-3.2.3/src/debug.c (revision ace86cfa)
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();
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();
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:%lu",
296             (void*)val, val->refcount,
297             strenc, (long long) rdbSavedObjectLen(val),
298             val->lru, estimateObjectIdleTime(val));
299     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
300         long keys, j;
301         robj *key, *val;
302         char buf[128];
303 
304         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
305             return;
306         for (j = 0; j < keys; j++) {
307             snprintf(buf,sizeof(buf),"key:%lu",j);
308             key = createStringObject(buf,strlen(buf));
309             if (lookupKeyRead(c->db,key) != NULL) {
310                 decrRefCount(key);
311                 continue;
312             }
313             snprintf(buf,sizeof(buf),"value:%lu",j);
314             val = createStringObject(buf,strlen(buf));
315             dbAdd(c->db,key,val);
316             decrRefCount(key);
317         }
318         addReply(c,shared.ok);
319     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
320         unsigned char digest[20];
321         sds d = sdsempty();
322         int j;
323 
324         computeDatasetDigest(digest);
325         for (j = 0; j < 20; j++)
326             d = sdscatprintf(d, "%02x",digest[j]);
327         addReplyStatus(c,d);
328         sdsfree(d);
329     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
330         double dtime = strtod(c->argv[2]->ptr,NULL);
331         long long utime = dtime*1000000;
332 
333         usleep(utime);
334         addReply(c,shared.ok);
335     } else if (!strcasecmp(c->argv[1]->ptr,"set-active-expire") &&
336                c->argc == 3)
337     {
338         server.active_expire_enabled = atoi(c->argv[2]->ptr);
339         addReply(c,shared.ok);
340     } else {
341         addReplyErrorFormat(c, "Unknown DEBUG subcommand or wrong number of arguments for '%s'",
342             (char*)c->argv[1]->ptr);
343     }
344 }
345 
346 /* =========================== Crash handling  ============================== */
347 
348 void _redisAssert(char *estr, char *file, int line) {
349     bugReportStart();
350     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
351     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
352 #ifdef HAVE_BACKTRACE
353     server.assert_failed = estr;
354     server.assert_file = file;
355     server.assert_line = line;
356     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
357 #endif
358     *((char*)-1) = 'x';
359 }
360 
361 void _redisAssertPrintClientInfo(redisClient *c) {
362     int j;
363 
364     bugReportStart();
365     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
366     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
367     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
368     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
369     for (j=0; j < c->argc; j++) {
370         char buf[128];
371         char *arg;
372 
373         if (c->argv[j]->type == REDIS_STRING &&
374             c->argv[j]->encoding == REDIS_ENCODING_RAW)
375         {
376             arg = (char*) c->argv[j]->ptr;
377         } else {
378             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
379                 c->argv[j]->type, c->argv[j]->encoding);
380             arg = buf;
381         }
382         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
383             j, arg, c->argv[j]->refcount);
384     }
385 }
386 
387 void redisLogObjectDebugInfo(robj *o) {
388     redisLog(REDIS_WARNING,"Object type: %d", o->type);
389     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
390     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
391     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
392         redisLog(REDIS_WARNING,"Object raw string len: %zu", sdslen(o->ptr));
393         if (sdslen(o->ptr) < 4096)
394             redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
395     } else if (o->type == REDIS_LIST) {
396         redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
397     } else if (o->type == REDIS_SET) {
398         redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
399     } else if (o->type == REDIS_HASH) {
400         redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
401     } else if (o->type == REDIS_ZSET) {
402         redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
403         if (o->encoding == REDIS_ENCODING_SKIPLIST)
404             redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
405     }
406 }
407 
408 void _redisAssertPrintObject(robj *o) {
409     bugReportStart();
410     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
411     redisLogObjectDebugInfo(o);
412 }
413 
414 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
415     if (c) _redisAssertPrintClientInfo(c);
416     if (o) _redisAssertPrintObject(o);
417     _redisAssert(estr,file,line);
418 }
419 
420 void _redisPanic(char *msg, char *file, int line) {
421     bugReportStart();
422     redisLog(REDIS_WARNING,"------------------------------------------------");
423     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
424     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
425 #ifdef HAVE_BACKTRACE
426     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
427 #endif
428     redisLog(REDIS_WARNING,"------------------------------------------------");
429     *((char*)-1) = 'x';
430 }
431 
432 void bugReportStart(void) {
433     if (server.bug_report_start == 0) {
434         redisLog(REDIS_WARNING,
435             "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
436         server.bug_report_start = 1;
437     }
438 }
439 
440 #ifdef HAVE_BACKTRACE
441 static void *getMcontextEip(ucontext_t *uc) {
442 #if defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
443     /* OSX < 10.6 */
444     #if defined(__x86_64__)
445     return (void*) uc->uc_mcontext->__ss.__rip;
446     #elif defined(__i386__)
447     return (void*) uc->uc_mcontext->__ss.__eip;
448     #else
449     return (void*) uc->uc_mcontext->__ss.__srr0;
450     #endif
451 #elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
452     /* OSX >= 10.6 */
453     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
454     return (void*) uc->uc_mcontext->__ss.__rip;
455     #else
456     return (void*) uc->uc_mcontext->__ss.__eip;
457     #endif
458 #elif defined(__linux__)
459     /* Linux */
460     #if defined(__i386__)
461     return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
462     #elif defined(__X86_64__) || defined(__x86_64__)
463     return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
464     #elif defined(__ia64__) /* Linux IA64 */
465     return (void*) uc->uc_mcontext.sc_ip;
466     #endif
467 #else
468     return NULL;
469 #endif
470 }
471 
472 void logStackContent(void **sp) {
473     int i;
474     for (i = 15; i >= 0; i--) {
475         unsigned long addr = (unsigned long) sp+i;
476         unsigned long val = (unsigned long) sp[i];
477 
478         if (sizeof(long) == 4)
479             redisLog(REDIS_WARNING, "(%08lx) -> %08lx", addr, val);
480         else
481             redisLog(REDIS_WARNING, "(%016lx) -> %016lx", addr, val);
482     }
483 }
484 
485 void logRegisters(ucontext_t *uc) {
486     redisLog(REDIS_WARNING, "--- REGISTERS");
487 
488 /* OSX */
489 #if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
490   /* OSX AMD64 */
491     #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
492     redisLog(REDIS_WARNING,
493     "\n"
494     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
495     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
496     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
497     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
498     "RIP:%016lx EFL:%016lx\nCS :%016lx FS:%016lx  GS:%016lx",
499         (unsigned long) uc->uc_mcontext->__ss.__rax,
500         (unsigned long) uc->uc_mcontext->__ss.__rbx,
501         (unsigned long) uc->uc_mcontext->__ss.__rcx,
502         (unsigned long) uc->uc_mcontext->__ss.__rdx,
503         (unsigned long) uc->uc_mcontext->__ss.__rdi,
504         (unsigned long) uc->uc_mcontext->__ss.__rsi,
505         (unsigned long) uc->uc_mcontext->__ss.__rbp,
506         (unsigned long) uc->uc_mcontext->__ss.__rsp,
507         (unsigned long) uc->uc_mcontext->__ss.__r8,
508         (unsigned long) uc->uc_mcontext->__ss.__r9,
509         (unsigned long) uc->uc_mcontext->__ss.__r10,
510         (unsigned long) uc->uc_mcontext->__ss.__r11,
511         (unsigned long) uc->uc_mcontext->__ss.__r12,
512         (unsigned long) uc->uc_mcontext->__ss.__r13,
513         (unsigned long) uc->uc_mcontext->__ss.__r14,
514         (unsigned long) uc->uc_mcontext->__ss.__r15,
515         (unsigned long) uc->uc_mcontext->__ss.__rip,
516         (unsigned long) uc->uc_mcontext->__ss.__rflags,
517         (unsigned long) uc->uc_mcontext->__ss.__cs,
518         (unsigned long) uc->uc_mcontext->__ss.__fs,
519         (unsigned long) uc->uc_mcontext->__ss.__gs
520     );
521     logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
522     #else
523     /* OSX x86 */
524     redisLog(REDIS_WARNING,
525     "\n"
526     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
527     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
528     "SS:%08lx  EFL:%08lx EIP:%08lx CS :%08lx\n"
529     "DS:%08lx  ES:%08lx  FS :%08lx GS :%08lx",
530         (unsigned long) uc->uc_mcontext->__ss.__eax,
531         (unsigned long) uc->uc_mcontext->__ss.__ebx,
532         (unsigned long) uc->uc_mcontext->__ss.__ecx,
533         (unsigned long) uc->uc_mcontext->__ss.__edx,
534         (unsigned long) uc->uc_mcontext->__ss.__edi,
535         (unsigned long) uc->uc_mcontext->__ss.__esi,
536         (unsigned long) uc->uc_mcontext->__ss.__ebp,
537         (unsigned long) uc->uc_mcontext->__ss.__esp,
538         (unsigned long) uc->uc_mcontext->__ss.__ss,
539         (unsigned long) uc->uc_mcontext->__ss.__eflags,
540         (unsigned long) uc->uc_mcontext->__ss.__eip,
541         (unsigned long) uc->uc_mcontext->__ss.__cs,
542         (unsigned long) uc->uc_mcontext->__ss.__ds,
543         (unsigned long) uc->uc_mcontext->__ss.__es,
544         (unsigned long) uc->uc_mcontext->__ss.__fs,
545         (unsigned long) uc->uc_mcontext->__ss.__gs
546     );
547     logStackContent((void**)uc->uc_mcontext->__ss.__esp);
548     #endif
549 /* Linux */
550 #elif defined(__linux__)
551     /* Linux x86 */
552     #if defined(__i386__)
553     redisLog(REDIS_WARNING,
554     "\n"
555     "EAX:%08lx EBX:%08lx ECX:%08lx EDX:%08lx\n"
556     "EDI:%08lx ESI:%08lx EBP:%08lx ESP:%08lx\n"
557     "SS :%08lx EFL:%08lx EIP:%08lx CS:%08lx\n"
558     "DS :%08lx ES :%08lx FS :%08lx GS:%08lx",
559         (unsigned long) uc->uc_mcontext.gregs[11],
560         (unsigned long) uc->uc_mcontext.gregs[8],
561         (unsigned long) uc->uc_mcontext.gregs[10],
562         (unsigned long) uc->uc_mcontext.gregs[9],
563         (unsigned long) uc->uc_mcontext.gregs[4],
564         (unsigned long) uc->uc_mcontext.gregs[5],
565         (unsigned long) uc->uc_mcontext.gregs[6],
566         (unsigned long) uc->uc_mcontext.gregs[7],
567         (unsigned long) uc->uc_mcontext.gregs[18],
568         (unsigned long) uc->uc_mcontext.gregs[17],
569         (unsigned long) uc->uc_mcontext.gregs[14],
570         (unsigned long) uc->uc_mcontext.gregs[15],
571         (unsigned long) uc->uc_mcontext.gregs[3],
572         (unsigned long) uc->uc_mcontext.gregs[2],
573         (unsigned long) uc->uc_mcontext.gregs[1],
574         (unsigned long) uc->uc_mcontext.gregs[0]
575     );
576     logStackContent((void**)uc->uc_mcontext.gregs[7]);
577     #elif defined(__X86_64__) || defined(__x86_64__)
578     /* Linux AMD64 */
579     redisLog(REDIS_WARNING,
580     "\n"
581     "RAX:%016lx RBX:%016lx\nRCX:%016lx RDX:%016lx\n"
582     "RDI:%016lx RSI:%016lx\nRBP:%016lx RSP:%016lx\n"
583     "R8 :%016lx R9 :%016lx\nR10:%016lx R11:%016lx\n"
584     "R12:%016lx R13:%016lx\nR14:%016lx R15:%016lx\n"
585     "RIP:%016lx EFL:%016lx\nCSGSFS:%016lx",
586         (unsigned long) uc->uc_mcontext.gregs[13],
587         (unsigned long) uc->uc_mcontext.gregs[11],
588         (unsigned long) uc->uc_mcontext.gregs[14],
589         (unsigned long) uc->uc_mcontext.gregs[12],
590         (unsigned long) uc->uc_mcontext.gregs[8],
591         (unsigned long) uc->uc_mcontext.gregs[9],
592         (unsigned long) uc->uc_mcontext.gregs[10],
593         (unsigned long) uc->uc_mcontext.gregs[15],
594         (unsigned long) uc->uc_mcontext.gregs[0],
595         (unsigned long) uc->uc_mcontext.gregs[1],
596         (unsigned long) uc->uc_mcontext.gregs[2],
597         (unsigned long) uc->uc_mcontext.gregs[3],
598         (unsigned long) uc->uc_mcontext.gregs[4],
599         (unsigned long) uc->uc_mcontext.gregs[5],
600         (unsigned long) uc->uc_mcontext.gregs[6],
601         (unsigned long) uc->uc_mcontext.gregs[7],
602         (unsigned long) uc->uc_mcontext.gregs[16],
603         (unsigned long) uc->uc_mcontext.gregs[17],
604         (unsigned long) uc->uc_mcontext.gregs[18]
605     );
606     logStackContent((void**)uc->uc_mcontext.gregs[15]);
607     #endif
608 #else
609     redisLog(REDIS_WARNING,
610         "  Dumping of registers not supported for this OS/arch");
611 #endif
612 }
613 
614 /* Logs the stack trace using the backtrace() call. This function is designed
615  * to be called from signal handlers safely. */
616 void logStackTrace(ucontext_t *uc) {
617     void *trace[100];
618     int trace_size = 0, fd;
619 
620     /* Open the log file in append mode. */
621     fd = server.logfile ?
622         open(server.logfile, O_APPEND|O_CREAT|O_WRONLY, 0644) :
623         STDOUT_FILENO;
624     if (fd == -1) return;
625 
626     /* Generate the stack trace */
627     trace_size = backtrace(trace, 100);
628 
629     /* overwrite sigaction with caller's address */
630     if (getMcontextEip(uc) != NULL)
631         trace[1] = getMcontextEip(uc);
632 
633     /* Write symbols to log file */
634     backtrace_symbols_fd(trace, trace_size, fd);
635 
636     /* Cleanup */
637     if (server.logfile) close(fd);
638 }
639 
640 /* Log information about the "current" client, that is, the client that is
641  * currently being served by Redis. May be NULL if Redis is not serving a
642  * client right now. */
643 void logCurrentClient(void) {
644     if (server.current_client == NULL) return;
645 
646     redisClient *cc = server.current_client;
647     sds client;
648     int j;
649 
650     redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
651     client = getClientInfoString(cc);
652     redisLog(REDIS_WARNING,"client: %s", client);
653     sdsfree(client);
654     for (j = 0; j < cc->argc; j++) {
655         robj *decoded;
656 
657         decoded = getDecodedObject(cc->argv[j]);
658         redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
659         decrRefCount(decoded);
660     }
661     /* Check if the first argument, usually a key, is found inside the
662      * selected DB, and if so print info about the associated object. */
663     if (cc->argc >= 1) {
664         robj *val, *key;
665         dictEntry *de;
666 
667         key = getDecodedObject(cc->argv[1]);
668         de = dictFind(cc->db->dict, key->ptr);
669         if (de) {
670             val = dictGetVal(de);
671             redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", (char*)key->ptr);
672             redisLogObjectDebugInfo(val);
673         }
674         decrRefCount(key);
675     }
676 }
677 
678 #if defined(HAVE_PROC_MAPS)
679 void memtest_non_destructive_invert(void *addr, size_t size);
680 void memtest_non_destructive_swap(void *addr, size_t size);
681 #define MEMTEST_MAX_REGIONS 128
682 
683 int memtest_test_linux_anonymous_maps(void) {
684     FILE *fp = fopen("/proc/self/maps","r");
685     char line[1024];
686     size_t start_addr, end_addr, size;
687     size_t start_vect[MEMTEST_MAX_REGIONS];
688     size_t size_vect[MEMTEST_MAX_REGIONS];
689     int regions = 0, j;
690     uint64_t crc1 = 0, crc2 = 0, crc3 = 0;
691 
692     while(fgets(line,sizeof(line),fp) != NULL) {
693         char *start, *end, *p = line;
694 
695         start = p;
696         p = strchr(p,'-');
697         if (!p) continue;
698         *p++ = '\0';
699         end = p;
700         p = strchr(p,' ');
701         if (!p) continue;
702         *p++ = '\0';
703         if (strstr(p,"stack") ||
704             strstr(p,"vdso") ||
705             strstr(p,"vsyscall")) continue;
706         if (!strstr(p,"00:00")) continue;
707         if (!strstr(p,"rw")) continue;
708 
709         start_addr = strtoul(start,NULL,16);
710         end_addr = strtoul(end,NULL,16);
711         size = end_addr-start_addr;
712 
713         start_vect[regions] = start_addr;
714         size_vect[regions] = size;
715         printf("Testing %lx %lu\n", (unsigned long) start_vect[regions],
716                                     (unsigned long) size_vect[regions]);
717         regions++;
718     }
719 
720     /* Test all the regions as an unique sequential region.
721      * 1) Take the CRC64 of the memory region. */
722     for (j = 0; j < regions; j++) {
723         crc1 = crc64(crc1,(void*)start_vect[j],size_vect[j]);
724     }
725 
726     /* 2) Invert bits, swap adjacent words, swap again, invert bits.
727      * This is the error amplification step. */
728     for (j = 0; j < regions; j++)
729         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
730     for (j = 0; j < regions; j++)
731         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
732     for (j = 0; j < regions; j++)
733         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
734     for (j = 0; j < regions; j++)
735         memtest_non_destructive_invert((void*)start_vect[j],size_vect[j]);
736 
737     /* 3) Take the CRC64 sum again. */
738     for (j = 0; j < regions; j++)
739         crc2 = crc64(crc2,(void*)start_vect[j],size_vect[j]);
740 
741     /* 4) Swap + Swap again */
742     for (j = 0; j < regions; j++)
743         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
744     for (j = 0; j < regions; j++)
745         memtest_non_destructive_swap((void*)start_vect[j],size_vect[j]);
746 
747     /* 5) Take the CRC64 sum again. */
748     for (j = 0; j < regions; j++)
749         crc3 = crc64(crc3,(void*)start_vect[j],size_vect[j]);
750 
751     /* NOTE: It is very important to close the file descriptor only now
752      * because closing it before may result into unmapping of some memory
753      * region that we are testing. */
754     fclose(fp);
755 
756     /* If the two CRC are not the same, we trapped a memory error. */
757     return crc1 != crc2 || crc2 != crc3;
758 }
759 #endif
760 
761 void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
762     ucontext_t *uc = (ucontext_t*) secret;
763     sds infostring, clients;
764     struct sigaction act;
765     REDIS_NOTUSED(info);
766 
767     bugReportStart();
768     redisLog(REDIS_WARNING,
769         "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
770     redisLog(REDIS_WARNING,
771         "    Failed assertion: %s (%s:%d)", server.assert_failed,
772                         server.assert_file, server.assert_line);
773 
774     /* Log the stack trace */
775     redisLog(REDIS_WARNING, "--- STACK TRACE");
776     logStackTrace(uc);
777 
778     /* Log INFO and CLIENT LIST */
779     redisLog(REDIS_WARNING, "--- INFO OUTPUT");
780     infostring = genRedisInfoString("all");
781     infostring = sdscatprintf(infostring, "hash_init_value: %u\n",
782         dictGetHashFunctionSeed());
783     redisLogRaw(REDIS_WARNING, infostring);
784     redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
785     clients = getAllClientsInfoString();
786     redisLogRaw(REDIS_WARNING, clients);
787     sdsfree(infostring);
788     sdsfree(clients);
789 
790     /* Log the current client */
791     logCurrentClient();
792 
793     /* Log dump of processor registers */
794     logRegisters(uc);
795 
796 #if defined(HAVE_PROC_MAPS)
797     /* Test memory */
798     redisLog(REDIS_WARNING, "--- FAST MEMORY TEST");
799     bioKillThreads();
800     if (memtest_test_linux_anonymous_maps()) {
801         redisLog(REDIS_WARNING,
802             "!!! MEMORY ERROR DETECTED! Check your memory ASAP !!!");
803     } else {
804         redisLog(REDIS_WARNING,
805             "Fast memory test PASSED, however your memory can still be broken. Please run a memory test for several hours if possible.");
806     }
807 #endif
808 
809     redisLog(REDIS_WARNING,
810 "\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
811 "       Please report the crash opening an issue on github:\n\n"
812 "           http://github.com/antirez/redis/issues\n\n"
813 "  Suspect RAM error? Use redis-server --test-memory to veryfy it.\n\n"
814 );
815     /* free(messages); Don't call free() with possibly corrupted memory. */
816     if (server.daemonize) unlink(server.pidfile);
817 
818     /* Make sure we exit with the right signal at the end. So for instance
819      * the core will be dumped if enabled. */
820     sigemptyset (&act.sa_mask);
821     act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
822     act.sa_handler = SIG_DFL;
823     sigaction (sig, &act, NULL);
824     kill(getpid(),sig);
825 }
826 #endif /* HAVE_BACKTRACE */
827 
828 /* ==================== Logging functions for debugging ===================== */
829 
830 void redisLogHexDump(int level, char *descr, void *value, size_t len) {
831     char buf[65], *b;
832     unsigned char *v = value;
833     char charset[] = "0123456789abcdef";
834 
835     redisLog(level,"%s (hexdump):", descr);
836     b = buf;
837     while(len) {
838         b[0] = charset[(*v)>>4];
839         b[1] = charset[(*v)&0xf];
840         b[2] = '\0';
841         b += 2;
842         len--;
843         v++;
844         if (b-buf == 64 || len == 0) {
845             redisLogRaw(level|REDIS_LOG_RAW,buf);
846             b = buf;
847         }
848     }
849     redisLogRaw(level|REDIS_LOG_RAW,"\n");
850 }
851 
852 /* =========================== Software Watchdog ============================ */
853 #include <sys/time.h>
854 
855 void watchdogSignalHandler(int sig, siginfo_t *info, void *secret) {
856 #ifdef HAVE_BACKTRACE
857     ucontext_t *uc = (ucontext_t*) secret;
858 #endif
859     REDIS_NOTUSED(info);
860     REDIS_NOTUSED(sig);
861 
862     redisLogFromHandler(REDIS_WARNING,"\n--- WATCHDOG TIMER EXPIRED ---");
863 #ifdef HAVE_BACKTRACE
864     logStackTrace(uc);
865 #else
866     redisLogFromHandler(REDIS_WARNING,"Sorry: no support for backtrace().");
867 #endif
868     redisLogFromHandler(REDIS_WARNING,"--------\n");
869 }
870 
871 /* Schedule a SIGALRM delivery after the specified period in milliseconds.
872  * If a timer is already scheduled, this function will re-schedule it to the
873  * specified time. If period is 0 the current timer is disabled. */
874 void watchdogScheduleSignal(int period) {
875     struct itimerval it;
876 
877     /* Will stop the timer if period is 0. */
878     it.it_value.tv_sec = period/1000;
879     it.it_value.tv_usec = (period%1000)*1000;
880     /* Don't automatically restart. */
881     it.it_interval.tv_sec = 0;
882     it.it_interval.tv_usec = 0;
883     setitimer(ITIMER_REAL, &it, NULL);
884 }
885 
886 /* Enable the software watchdog with the specified period in milliseconds. */
887 void enableWatchdog(int period) {
888     int min_period;
889 
890     if (server.watchdog_period == 0) {
891         struct sigaction act;
892 
893         /* Watchdog was actually disabled, so we have to setup the signal
894          * handler. */
895         sigemptyset(&act.sa_mask);
896         act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_SIGINFO;
897         act.sa_sigaction = watchdogSignalHandler;
898         sigaction(SIGALRM, &act, NULL);
899     }
900     /* If the configured period is smaller than twice the timer period, it is
901      * too short for the software watchdog to work reliably. Fix it now
902      * if needed. */
903     min_period = (1000/server.hz)*2;
904     if (period < min_period) period = min_period;
905     watchdogScheduleSignal(period); /* Adjust the current timer. */
906     server.watchdog_period = period;
907 }
908 
909 /* Disable the software watchdog. */
910 void disableWatchdog(void) {
911     struct sigaction act;
912     if (server.watchdog_period == 0) return; /* Already disabled. */
913     watchdogScheduleSignal(0); /* Stop the current timer. */
914 
915     /* Set the signal handler to SIG_IGN, this will also remove pending
916      * signals from the queue. */
917     sigemptyset(&act.sa_mask);
918     act.sa_flags = 0;
919     act.sa_handler = SIG_IGN;
920     sigaction(SIGALRM, &act, NULL);
921     server.watchdog_period = 0;
922 }
923