src/debug.c

#include "redis.h"
#include "sha1.h"   /* SHA1 is used for DEBUG DIGEST */

#include <arpa/inet.h>
#include <signal.h>

#ifdef HAVE_BACKTRACE
#include <execinfo.h>
#include <ucontext.h>
#endif /* HAVE_BACKTRACE */

/* ================================= Debugging ============================== */

/* Compute the sha1 of string at 's' with 'len' bytes long.
 * The SHA1 is then xored againt the string pointed by digest.
 * Since xor is commutative, this operation is used in order to
 * "add" digests relative to unordered elements.
 *
 * So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
void xorDigest(unsigned char *digest, void *ptr, size_t len) {
    SHA1_CTX ctx;
    unsigned char hash[20], *s = ptr;
    int j;

    SHA1Init(&ctx);
    SHA1Update(&ctx,s,len);
    SHA1Final(hash,&ctx);

    for (j = 0; j < 20; j++)
        digest[j] ^= hash[j];
}

void xorObjectDigest(unsigned char *digest, robj *o) {
    o = getDecodedObject(o);
    xorDigest(digest,o->ptr,sdslen(o->ptr));
    decrRefCount(o);
}

/* This function instead of just computing the SHA1 and xoring it
 * against diget, also perform the digest of "digest" itself and
 * replace the old value with the new one.
 *
 * So the final digest will be:
 *
 * digest = SHA1(digest xor SHA1(data))
 *
 * This function is used every time we want to preserve the order so
 * that digest(a,b,c,d) will be different than digest(b,c,d,a)
 *
 * Also note that mixdigest("foo") followed by mixdigest("bar")
 * will lead to a different digest compared to "fo", "obar".
 */
void mixDigest(unsigned char *digest, void *ptr, size_t len) {
    SHA1_CTX ctx;
    char *s = ptr;

    xorDigest(digest,s,len);
    SHA1Init(&ctx);
    SHA1Update(&ctx,digest,20);
    SHA1Final(digest,&ctx);
}

void mixObjectDigest(unsigned char *digest, robj *o) {
    o = getDecodedObject(o);
    mixDigest(digest,o->ptr,sdslen(o->ptr));
    decrRefCount(o);
}

/* Compute the dataset digest. Since keys, sets elements, hashes elements
 * are not ordered, we use a trick: every aggregate digest is the xor
 * of the digests of their elements. This way the order will not change
 * the result. For list instead we use a feedback entering the output digest
 * as input in order to ensure that a different ordered list will result in
 * a different digest. */
void computeDatasetDigest(unsigned char *final) {
    unsigned char digest[20];
    char buf[128];
    dictIterator *di = NULL;
    dictEntry *de;
    int j;
    uint32_t aux;

    memset(final,0,20); /* Start with a clean result */

    for (j = 0; j < server.dbnum; j++) {
        redisDb *db = server.db+j;

        if (dictSize(db->dict) == 0) continue;
        di = dictGetIterator(db->dict);

        /* hash the DB id, so the same dataset moved in a different
         * DB will lead to a different digest */
        aux = htonl(j);
        mixDigest(final,&aux,sizeof(aux));

        /* Iterate this DB writing every entry */
        while((de = dictNext(di)) != NULL) {
            sds key;
            robj *keyobj, *o;
            long long expiretime;

            memset(digest,0,20); /* This key-val digest */
            key = dictGetKey(de);
            keyobj = createStringObject(key,sdslen(key));

            mixDigest(digest,key,sdslen(key));

            /* Make sure the key is loaded if VM is active */
            o = dictGetVal(de);

            aux = htonl(o->type);
            mixDigest(digest,&aux,sizeof(aux));
            expiretime = getExpire(db,keyobj);

            /* Save the key and associated value */
            if (o->type == REDIS_STRING) {
                mixObjectDigest(digest,o);
            } else if (o->type == REDIS_LIST) {
                listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
                listTypeEntry entry;
                while(listTypeNext(li,&entry)) {
                    robj *eleobj = listTypeGet(&entry);
                    mixObjectDigest(digest,eleobj);
                    decrRefCount(eleobj);
                }
                listTypeReleaseIterator(li);
            } else if (o->type == REDIS_SET) {
                setTypeIterator *si = setTypeInitIterator(o);
                robj *ele;
                while((ele = setTypeNextObject(si)) != NULL) {
                    xorObjectDigest(digest,ele);
                    decrRefCount(ele);
                }
                setTypeReleaseIterator(si);
            } else if (o->type == REDIS_ZSET) {
                unsigned char eledigest[20];

                if (o->encoding == REDIS_ENCODING_ZIPLIST) {
                    unsigned char *zl = o->ptr;
                    unsigned char *eptr, *sptr;
                    unsigned char *vstr;
                    unsigned int vlen;
                    long long vll;
                    double score;

                    eptr = ziplistIndex(zl,0);
                    redisAssert(eptr != NULL);
                    sptr = ziplistNext(zl,eptr);
                    redisAssert(sptr != NULL);

                    while (eptr != NULL) {
                        redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
                        score = zzlGetScore(sptr);

                        memset(eledigest,0,20);
                        if (vstr != NULL) {
                            mixDigest(eledigest,vstr,vlen);
                        } else {
                            ll2string(buf,sizeof(buf),vll);
                            mixDigest(eledigest,buf,strlen(buf));
                        }

                        snprintf(buf,sizeof(buf),"%.17g",score);
                        mixDigest(eledigest,buf,strlen(buf));
                        xorDigest(digest,eledigest,20);
                        zzlNext(zl,&eptr,&sptr);
                    }
                } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
                    zset *zs = o->ptr;
                    dictIterator *di = dictGetIterator(zs->dict);
                    dictEntry *de;

                    while((de = dictNext(di)) != NULL) {
                        robj *eleobj = dictGetKey(de);
                        double *score = dictGetVal(de);

                        snprintf(buf,sizeof(buf),"%.17g",*score);
                        memset(eledigest,0,20);
                        mixObjectDigest(eledigest,eleobj);
                        mixDigest(eledigest,buf,strlen(buf));
                        xorDigest(digest,eledigest,20);
                    }
                    dictReleaseIterator(di);
                } else {
                    redisPanic("Unknown sorted set encoding");
                }
            } else if (o->type == REDIS_HASH) {
                hashTypeIterator *hi;
                robj *obj;

                hi = hashTypeInitIterator(o);
                while (hashTypeNext(hi) != REDIS_ERR) {
                    unsigned char eledigest[20];

                    memset(eledigest,0,20);
                    obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
                    mixObjectDigest(eledigest,obj);
                    decrRefCount(obj);
                    obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
                    mixObjectDigest(eledigest,obj);
                    decrRefCount(obj);
                    xorDigest(digest,eledigest,20);
                }
                hashTypeReleaseIterator(hi);
            } else {
                redisPanic("Unknown object type");
            }
            /* If the key has an expire, add it to the mix */
            if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
            /* We can finally xor the key-val digest to the final digest */
            xorDigest(final,digest,20);
            decrRefCount(keyobj);
        }
        dictReleaseIterator(di);
    }
}

void debugCommand(redisClient *c) {
    if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
        *((char*)-1) = 'x';
    } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
        if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
        redisAssertWithInfo(c,c->argv[0],1 == 2);
    } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
        if (rdbSave(server.rdb_filename) != REDIS_OK) {
            addReply(c,shared.err);
            return;
        }
        emptyDb();
        if (rdbLoad(server.rdb_filename) != REDIS_OK) {
            addReplyError(c,"Error trying to load the RDB dump");
            return;
        }
        redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
        addReply(c,shared.ok);
    } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
        emptyDb();
        if (loadAppendOnlyFile(server.aof_filename) != REDIS_OK) {
            addReply(c,shared.err);
            return;
        }
        server.dirty = 0; /* Prevent AOF / replication */
        redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
        addReply(c,shared.ok);
    } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
        dictEntry *de;
        robj *val;
        char *strenc;

        if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
            addReply(c,shared.nokeyerr);
            return;
        }
        val = dictGetVal(de);
        strenc = strEncoding(val->encoding);

        addReplyStatusFormat(c,
            "Value at:%p refcount:%d "
            "encoding:%s serializedlength:%lld "
            "lru:%d lru_seconds_idle:%lu",
            (void*)val, val->refcount,
            strenc, (long long) rdbSavedObjectLen(val),
            val->lru, estimateObjectIdleTime(val));
    } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
        long keys, j;
        robj *key, *val;
        char buf[128];

        if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
            return;
        for (j = 0; j < keys; j++) {
            snprintf(buf,sizeof(buf),"key:%lu",j);
            key = createStringObject(buf,strlen(buf));
            if (lookupKeyRead(c->db,key) != NULL) {
                decrRefCount(key);
                continue;
            }
            snprintf(buf,sizeof(buf),"value:%lu",j);
            val = createStringObject(buf,strlen(buf));
            dbAdd(c->db,key,val);
            decrRefCount(key);
        }
        addReply(c,shared.ok);
    } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
        unsigned char digest[20];
        sds d = sdsempty();
        int j;

        computeDatasetDigest(digest);
        for (j = 0; j < 20; j++)
            d = sdscatprintf(d, "%02x",digest[j]);
        addReplyStatus(c,d);
        sdsfree(d);
    } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
        double dtime = strtod(c->argv[2]->ptr,NULL);
        long long utime = dtime*1000000;

        usleep(utime);
        addReply(c,shared.ok);
    } else {
        addReplyError(c,
            "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
    }
}

/* =========================== Crash handling  ============================== */

void _redisAssert(char *estr, char *file, int line) {
    bugReportStart();
    redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
    redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
#ifdef HAVE_BACKTRACE
    server.assert_failed = estr;
    server.assert_file = file;
    server.assert_line = line;
    redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
    *((char*)-1) = 'x';
#endif
}

void _redisAssertPrintClientInfo(redisClient *c) {
    int j;

    bugReportStart();
    redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
    redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
    redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
    redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
    for (j=0; j < c->argc; j++) {
        char buf[128];
        char *arg;

        if (c->argv[j]->type == REDIS_STRING &&
            c->argv[j]->encoding == REDIS_ENCODING_RAW)
        {
            arg = (char*) c->argv[j]->ptr;
        } else {
            snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
                c->argv[j]->type, c->argv[j]->encoding);
            arg = buf;
        }
        redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
            j, arg, c->argv[j]->refcount);
    }
}

void redisLogObjectDebugInfo(robj *o) {
    redisLog(REDIS_WARNING,"Object type: %d", o->type);
    redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
    redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
    if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
        redisLog(REDIS_WARNING,"Object raw string len: %d", sdslen(o->ptr));
        if (sdslen(o->ptr) < 4096)
            redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
    } else if (o->type == REDIS_LIST) {
        redisLog(REDIS_WARNING,"List length: %d", (int) listTypeLength(o));
    } else if (o->type == REDIS_SET) {
        redisLog(REDIS_WARNING,"Set size: %d", (int) setTypeSize(o));
    } else if (o->type == REDIS_HASH) {
        redisLog(REDIS_WARNING,"Hash size: %d", (int) hashTypeLength(o));
    } else if (o->type == REDIS_ZSET) {
        redisLog(REDIS_WARNING,"Sorted set size: %d", (int) zsetLength(o));
        if (o->encoding == REDIS_ENCODING_SKIPLIST)
            redisLog(REDIS_WARNING,"Skiplist level: %d", (int) ((zset*)o->ptr)->zsl->level);
    }
}

void _redisAssertPrintObject(robj *o) {
    bugReportStart();
    redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
    redisLogObjectDebugInfo(o);
}

void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
    if (c) _redisAssertPrintClientInfo(c);
    if (o) _redisAssertPrintObject(o);
    _redisAssert(estr,file,line);
}

void _redisPanic(char *msg, char *file, int line) {
    bugReportStart();
    redisLog(REDIS_WARNING,"------------------------------------------------");
    redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
    redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
#ifdef HAVE_BACKTRACE
    redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
    redisLog(REDIS_WARNING,"------------------------------------------------");
    *((char*)-1) = 'x';
#endif
}

#ifdef HAVE_BACKTRACE
static void *getMcontextEip(ucontext_t *uc) {
#if defined(__FreeBSD__)
    return (void*) uc->uc_mcontext.mc_eip;
#elif defined(__dietlibc__)
    return (void*) uc->uc_mcontext.eip;
#elif defined(__APPLE__) && !defined(MAC_OS_X_VERSION_10_6)
  #if __x86_64__
    return (void*) uc->uc_mcontext->__ss.__rip;
  #elif __i386__
    return (void*) uc->uc_mcontext->__ss.__eip;
  #else
    return (void*) uc->uc_mcontext->__ss.__srr0;
  #endif
#elif defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
  #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
    return (void*) uc->uc_mcontext->__ss.__rip;
  #else
    return (void*) uc->uc_mcontext->__ss.__eip;
  #endif
#elif defined(__i386__)
    return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
#elif defined(__X86_64__) || defined(__x86_64__)
    return (void*) uc->uc_mcontext.gregs[16]; /* Linux 64 */
#elif defined(__ia64__) /* Linux IA64 */
    return (void*) uc->uc_mcontext.sc_ip;
#else
    return NULL;
#endif
}

void bugReportStart(void) {
    if (server.bug_report_start == 0) {
        redisLog(REDIS_WARNING,
            "\n\n=== REDIS BUG REPORT START: Cut & paste starting from here ===");
        server.bug_report_start = 1;
    }
}

void logStackContent(void **sp) {
    int i;
    for (i = 15; i >= 0; i--) {
        redisLog(REDIS_WARNING, "(%p) -> %p", sp+i, sp[i]);
    }
}

void logRegisters(ucontext_t *uc) {
    redisLog(REDIS_WARNING, "--- REGISTERS");
#if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
  #if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
    redisLog(REDIS_WARNING,
    "\n"
    "RAX:%p RBX:%p RCX:%p RDX:%p\n"
    "RDI:%p RSI:%p RBP:%p RSP:%p\n"
    "R8:%p  R9:%p  R10:%p R11:%p\n"
    "R12:%p R13:%p R14:%p R15:%p\n"
    "RIP:%p EFL:%p CS:%p  FS:%p GS:%p",
        uc->uc_mcontext->__ss.__rax,
        uc->uc_mcontext->__ss.__rbx,
        uc->uc_mcontext->__ss.__rcx,
        uc->uc_mcontext->__ss.__rdx,
        uc->uc_mcontext->__ss.__rdi,
        uc->uc_mcontext->__ss.__rsi,
        uc->uc_mcontext->__ss.__rbp,
        uc->uc_mcontext->__ss.__rsp,
        uc->uc_mcontext->__ss.__r8,
        uc->uc_mcontext->__ss.__r9,
        uc->uc_mcontext->__ss.__r10,
        uc->uc_mcontext->__ss.__r11,
        uc->uc_mcontext->__ss.__r12,
        uc->uc_mcontext->__ss.__r13,
        uc->uc_mcontext->__ss.__r14,
        uc->uc_mcontext->__ss.__r15,
        uc->uc_mcontext->__ss.__rip,
        uc->uc_mcontext->__ss.__rflags,
        uc->uc_mcontext->__ss.__cs,
        uc->uc_mcontext->__ss.__fs,
        uc->uc_mcontext->__ss.__gs
    );
    logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
  #else
    redisLog(REDIS_WARNING,
    "\n"
    "EAX:%p EBX:%p ECX:%p EDX:%p\n"
    "EDI:%p ESI:%p EBP:%p ESP:%p\n"
    "SS:%p  EFL:%p EIP:%p CS:%p\n"
    "DS:%p  ES:%p  FS:%p  GS:%p",
        uc->uc_mcontext->__ss.__eax,
        uc->uc_mcontext->__ss.__ebx,
        uc->uc_mcontext->__ss.__ecx,
        uc->uc_mcontext->__ss.__edx,
        uc->uc_mcontext->__ss.__edi,
        uc->uc_mcontext->__ss.__esi,
        uc->uc_mcontext->__ss.__ebp,
        uc->uc_mcontext->__ss.__esp,
        uc->uc_mcontext->__ss.__ss,
        uc->uc_mcontext->__ss.__eflags,
        uc->uc_mcontext->__ss.__eip,
        uc->uc_mcontext->__ss.__cs,
        uc->uc_mcontext->__ss.__ds,
        uc->uc_mcontext->__ss.__es,
        uc->uc_mcontext->__ss.__fs,
        uc->uc_mcontext->__ss.__gs
    );
    logStackContent((void**)uc->uc_mcontext->__ss.__esp);
  #endif
#elif defined(__i386__)
    return (void*) uc->uc_mcontext.gregs[14]; /* Linux 32 */
#elif defined(__X86_64__) || defined(__x86_64__)
    redisLog(REDIS_WARNING,
    "\n"
    "RAX:%p RBX:%p RCX:%p RDX:%p\n"
    "RDI:%p RSI:%p RBP:%p RSP:%p\n"
    "R8:%p  R9:%p  R10:%p R11:%p\n"
    "R12:%p R13:%p R14:%p R15:%p\n"
    "RIP:%p EFL:%p CSGSFS:%p",
        uc->uc_mcontext.gregs[13],
        uc->uc_mcontext.gregs[11],
        uc->uc_mcontext.gregs[14],
        uc->uc_mcontext.gregs[12],
        uc->uc_mcontext.gregs[8],
        uc->uc_mcontext.gregs[9],
        uc->uc_mcontext.gregs[10],
        uc->uc_mcontext.gregs[15],
        uc->uc_mcontext.gregs[0],
        uc->uc_mcontext.gregs[1],
        uc->uc_mcontext.gregs[2],
        uc->uc_mcontext.gregs[3],
        uc->uc_mcontext.gregs[4],
        uc->uc_mcontext.gregs[5],
        uc->uc_mcontext.gregs[6],
        uc->uc_mcontext.gregs[7],
        uc->uc_mcontext.gregs[16],
        uc->uc_mcontext.gregs[17],
        uc->uc_mcontext.gregs[18]
    );
    logStackContent((void**)uc->uc_mcontext.gregs[15]);
#else
    redisLog(REDIS_WARNING,
        "  Dumping of registers not supported for this OS/arch");
#endif
}

void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
    void *trace[100];
    char **messages = NULL;
    int i, trace_size = 0;
    ucontext_t *uc = (ucontext_t*) secret;
    sds infostring, clients;
    struct sigaction act;
    REDIS_NOTUSED(info);

    bugReportStart();
    redisLog(REDIS_WARNING,
        "    Redis %s crashed by signal: %d", REDIS_VERSION, sig);
    redisLog(REDIS_WARNING,
        "    Failed assertion: %s (%s:%d)", server.assert_failed,
                        server.assert_file, server.assert_line);

    /* Generate the stack trace */
    trace_size = backtrace(trace, 100);

    /* overwrite sigaction with caller's address */
    if (getMcontextEip(uc) != NULL) {
        trace[1] = getMcontextEip(uc);
    }
    messages = backtrace_symbols(trace, trace_size);
    redisLog(REDIS_WARNING, "--- STACK TRACE");
    for (i=1; i<trace_size; ++i)
        redisLog(REDIS_WARNING,"%s", messages[i]);

    /* Log INFO and CLIENT LIST */
    redisLog(REDIS_WARNING, "--- INFO OUTPUT");
    infostring = genRedisInfoString("all");
    redisLogRaw(REDIS_WARNING, infostring);
    redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
    clients = getAllClientsInfoString();
    redisLogRaw(REDIS_WARNING, clients);
    /* Don't sdsfree() strings to avoid a crash. Memory may be corrupted. */

    /* Log CURRENT CLIENT info */
    if (server.current_client) {
        redisClient *cc = server.current_client;
        sds client;
        int j;

        redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
        client = getClientInfoString(cc);
        redisLog(REDIS_WARNING,"client: %s", client);
        /* Missing sdsfree(client) to avoid crash if memory is corrupted. */
        for (j = 0; j < cc->argc; j++) {
            robj *decoded;

            decoded = getDecodedObject(cc->argv[j]);
            redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
            decrRefCount(decoded);
        }
        /* Check if the first argument, usually a key, is found inside the
         * selected DB, and if so print info about the associated object. */
        if (cc->argc >= 1) {
            robj *val, *key;
            dictEntry *de;

            key = getDecodedObject(cc->argv[1]);
            de = dictFind(cc->db->dict, key->ptr);
            if (de) {
                val = dictGetVal(de);
                redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
                redisLogObjectDebugInfo(val);
            }
            decrRefCount(key);
        }
    }

    /* Log dump of processor registers */
    logRegisters(uc);

    redisLog(REDIS_WARNING,
"\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
"    Please report the crash opening an issue on github:\n\n"
"        http://github.com/antirez/redis/issues\n\n"
);
    /* free(messages); Don't call free() with possibly corrupted memory. */
    if (server.daemonize) unlink(server.pidfile);

    /* Make sure we exit with the right signal at the end. So for instance
     * the core will be dumped if enabled. */
    sigemptyset (&act.sa_mask);
    /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
     * is used. Otherwise, sa_handler is used */
    act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
    act.sa_handler = SIG_DFL;
    sigaction (sig, &act, NULL);
    kill(getpid(),sig);
}
#endif /* HAVE_BACKTRACE */
Commit	Line	Data
	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	redisLog(REDIS_WARNING, "(%p) -> %p", sp+i, sp[i]);
	435	}
	436	}
	437
	438	void logRegisters(ucontext_t *uc) {
	439	redisLog(REDIS_WARNING, "--- REGISTERS");
	440	#if defined(__APPLE__) && defined(MAC_OS_X_VERSION_10_6)
	441	#if defined(_STRUCT_X86_THREAD_STATE64) && !defined(__i386__)
	442	redisLog(REDIS_WARNING,
	443	"\n"
	444	"RAX:%p RBX:%p RCX:%p RDX:%p\n"
	445	"RDI:%p RSI:%p RBP:%p RSP:%p\n"
	446	"R8:%p R9:%p R10:%p R11:%p\n"
	447	"R12:%p R13:%p R14:%p R15:%p\n"
	448	"RIP:%p EFL:%p CS:%p FS:%p GS:%p",
	449	uc->uc_mcontext->__ss.__rax,
	450	uc->uc_mcontext->__ss.__rbx,
	451	uc->uc_mcontext->__ss.__rcx,
	452	uc->uc_mcontext->__ss.__rdx,
	453	uc->uc_mcontext->__ss.__rdi,
	454	uc->uc_mcontext->__ss.__rsi,
	455	uc->uc_mcontext->__ss.__rbp,
	456	uc->uc_mcontext->__ss.__rsp,
	457	uc->uc_mcontext->__ss.__r8,
	458	uc->uc_mcontext->__ss.__r9,
	459	uc->uc_mcontext->__ss.__r10,
	460	uc->uc_mcontext->__ss.__r11,
	461	uc->uc_mcontext->__ss.__r12,
	462	uc->uc_mcontext->__ss.__r13,
	463	uc->uc_mcontext->__ss.__r14,
	464	uc->uc_mcontext->__ss.__r15,
	465	uc->uc_mcontext->__ss.__rip,
	466	uc->uc_mcontext->__ss.__rflags,
	467	uc->uc_mcontext->__ss.__cs,
	468	uc->uc_mcontext->__ss.__fs,
	469	uc->uc_mcontext->__ss.__gs
	470	);
	471	logStackContent((void**)uc->uc_mcontext->__ss.__rsp);
	472	#else
	473	redisLog(REDIS_WARNING,
	474	"\n"
	475	"EAX:%p EBX:%p ECX:%p EDX:%p\n"
	476	"EDI:%p ESI:%p EBP:%p ESP:%p\n"
	477	"SS:%p EFL:%p EIP:%p CS:%p\n"
	478	"DS:%p ES:%p FS:%p GS:%p",
	479	uc->uc_mcontext->__ss.__eax,
	480	uc->uc_mcontext->__ss.__ebx,
	481	uc->uc_mcontext->__ss.__ecx,
	482	uc->uc_mcontext->__ss.__edx,
	483	uc->uc_mcontext->__ss.__edi,
	484	uc->uc_mcontext->__ss.__esi,
	485	uc->uc_mcontext->__ss.__ebp,
	486	uc->uc_mcontext->__ss.__esp,
	487	uc->uc_mcontext->__ss.__ss,
	488	uc->uc_mcontext->__ss.__eflags,
	489	uc->uc_mcontext->__ss.__eip,
	490	uc->uc_mcontext->__ss.__cs,
	491	uc->uc_mcontext->__ss.__ds,
	492	uc->uc_mcontext->__ss.__es,
	493	uc->uc_mcontext->__ss.__fs,
	494	uc->uc_mcontext->__ss.__gs
	495	);
	496	logStackContent((void**)uc->uc_mcontext->__ss.__esp);
	497	#endif
	498	#elif defined(__i386__)
	499	return (void) uc->uc_mcontext.gregs[14]; / Linux 32 */
	500	#elif defined(__X86_64__) \|\| defined(__x86_64__)
	501	redisLog(REDIS_WARNING,
	502	"\n"
	503	"RAX:%p RBX:%p RCX:%p RDX:%p\n"
	504	"RDI:%p RSI:%p RBP:%p RSP:%p\n"
	505	"R8:%p R9:%p R10:%p R11:%p\n"
	506	"R12:%p R13:%p R14:%p R15:%p\n"
	507	"RIP:%p EFL:%p CSGSFS:%p",
	508	uc->uc_mcontext.gregs[13],
	509	uc->uc_mcontext.gregs[11],
	510	uc->uc_mcontext.gregs[14],
	511	uc->uc_mcontext.gregs[12],
	512	uc->uc_mcontext.gregs[8],
	513	uc->uc_mcontext.gregs[9],
	514	uc->uc_mcontext.gregs[10],
	515	uc->uc_mcontext.gregs[15],
	516	uc->uc_mcontext.gregs[0],
	517	uc->uc_mcontext.gregs[1],
	518	uc->uc_mcontext.gregs[2],
	519	uc->uc_mcontext.gregs[3],
	520	uc->uc_mcontext.gregs[4],
	521	uc->uc_mcontext.gregs[5],
	522	uc->uc_mcontext.gregs[6],
	523	uc->uc_mcontext.gregs[7],
	524	uc->uc_mcontext.gregs[16],
	525	uc->uc_mcontext.gregs[17],
	526	uc->uc_mcontext.gregs[18]
	527	);
	528	logStackContent((void**)uc->uc_mcontext.gregs[15]);
	529	#else
	530	redisLog(REDIS_WARNING,
	531	" Dumping of registers not supported for this OS/arch");
	532	#endif
	533	}
	534
	535	void sigsegvHandler(int sig, siginfo_t info, void secret) {
	536	void *trace[100];
	537	char **messages = NULL;
	538	int i, trace_size = 0;
	539	ucontext_t uc = (ucontext_t) secret;
	540	sds infostring, clients;
	541	struct sigaction act;
	542	REDIS_NOTUSED(info);
	543
	544	bugReportStart();
	545	redisLog(REDIS_WARNING,
	546	" Redis %s crashed by signal: %d", REDIS_VERSION, sig);
	547	redisLog(REDIS_WARNING,
	548	" Failed assertion: %s (%s:%d)", server.assert_failed,
	549	server.assert_file, server.assert_line);
	550
	551	/* Generate the stack trace */
	552	trace_size = backtrace(trace, 100);
	553
	554	/* overwrite sigaction with caller's address */
	555	if (getMcontextEip(uc) != NULL) {
	556	trace[1] = getMcontextEip(uc);
	557	}
	558	messages = backtrace_symbols(trace, trace_size);
	559	redisLog(REDIS_WARNING, "--- STACK TRACE");
	560	for (i=1; i<trace_size; ++i)
	561	redisLog(REDIS_WARNING,"%s", messages[i]);
	562
	563	/* Log INFO and CLIENT LIST */
	564	redisLog(REDIS_WARNING, "--- INFO OUTPUT");
	565	infostring = genRedisInfoString("all");
	566	redisLogRaw(REDIS_WARNING, infostring);
	567	redisLog(REDIS_WARNING, "--- CLIENT LIST OUTPUT");
	568	clients = getAllClientsInfoString();
	569	redisLogRaw(REDIS_WARNING, clients);
	570	/* Don't sdsfree() strings to avoid a crash. Memory may be corrupted. */
	571
	572	/* Log CURRENT CLIENT info */
	573	if (server.current_client) {
	574	redisClient *cc = server.current_client;
	575	sds client;
	576	int j;
	577
	578	redisLog(REDIS_WARNING, "--- CURRENT CLIENT INFO");
	579	client = getClientInfoString(cc);
	580	redisLog(REDIS_WARNING,"client: %s", client);
	581	/* Missing sdsfree(client) to avoid crash if memory is corrupted. */
	582	for (j = 0; j < cc->argc; j++) {
	583	robj *decoded;
	584
	585	decoded = getDecodedObject(cc->argv[j]);
	586	redisLog(REDIS_WARNING,"argv[%d]: '%s'", j, (char*)decoded->ptr);
	587	decrRefCount(decoded);
	588	}
	589	/* Check if the first argument, usually a key, is found inside the
	590	* selected DB, and if so print info about the associated object. */
	591	if (cc->argc >= 1) {
	592	robj val, key;
	593	dictEntry *de;
	594
	595	key = getDecodedObject(cc->argv[1]);
	596	de = dictFind(cc->db->dict, key->ptr);
	597	if (de) {
	598	val = dictGetVal(de);
	599	redisLog(REDIS_WARNING,"key '%s' found in DB containing the following object:", key->ptr);
	600	redisLogObjectDebugInfo(val);
	601	}
	602	decrRefCount(key);
	603	}
	604	}
	605
	606	/* Log dump of processor registers */
	607	logRegisters(uc);
	608
	609	redisLog(REDIS_WARNING,
	610	"\n=== REDIS BUG REPORT END. Make sure to include from START to END. ===\n\n"
	611	" Please report the crash opening an issue on github:\n\n"
	612	" http://github.com/antirez/redis/issues\n\n"
	613	);
	614	/* free(messages); Don't call free() with possibly corrupted memory. */
	615	if (server.daemonize) unlink(server.pidfile);
	616
	617	/* Make sure we exit with the right signal at the end. So for instance
	618	* the core will be dumped if enabled. */
	619	sigemptyset (&act.sa_mask);
	620	/* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
	621	* is used. Otherwise, sa_handler is used */
	622	act.sa_flags = SA_NODEFER \| SA_ONSTACK \| SA_RESETHAND;
	623	act.sa_handler = SIG_DFL;
	624	sigaction (sig, &act, NULL);
	625	kill(getpid(),sig);
	626	}
	627	#endif /* HAVE_BACKTRACE */