src/debug.c

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

#include <arpa/inet.h>

/* ================================= 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;
            time_t expiretime;

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

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

            /* Make sure the key is loaded if VM is active */
            o = lookupKeyRead(db,keyobj);

            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) {
                zset *zs = o->ptr;
                dictIterator *di = dictGetIterator(zs->dict);
                dictEntry *de;

                while((de = dictNext(di)) != NULL) {
                    robj *eleobj = dictGetEntryKey(de);
                    double *score = dictGetEntryVal(de);
                    unsigned char eledigest[20];

                    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 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,"flushcache")) {
        if (!server.ds_enabled) {
            addReplyError(c, "DEBUG FLUSHCACHE called with diskstore off.");
            return;
        } else if (server.bgsavethread != (pthread_t) -1) {
            addReplyError(c, "Can't flush cache while BGSAVE is in progress.");
            return;
        } else {
            /* To flush the whole cache we need to wait for everything to
             * be flushed on disk... */
            cacheForcePointInTime();
            emptyDb();
            addReply(c,shared.ok);
            return;
        }
    } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
        if (server.ds_enabled) {
            addReply(c,shared.ok);
            return;
        }
        if (rdbSave(server.dbfilename) != REDIS_OK) {
            addReply(c,shared.err);
            return;
        }
        emptyDb();
        if (rdbLoad(server.dbfilename) != REDIS_OK) {
            addReply(c,shared.err);
            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.appendfilename) != REDIS_OK) {
            addReply(c,shared.err);
            return;
        }
        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 (server.ds_enabled) lookupKeyRead(c->db,c->argv[2]);
        if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
            addReply(c,shared.nokeyerr);
            return;
        }
        val = dictGetEntryVal(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 {
        addReplyError(c,
            "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
    }
}

void _redisAssert(char *estr, char *file, int line) {
    redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
    redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
#ifdef HAVE_BACKTRACE
    redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
    *((char*)-1) = 'x';
#endif
}

void _redisPanic(char *msg, char *file, int line) {
    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
}
Commit	Line	Data
	1	#include "redis.h"
	2	#include "sha1.h" /* SHA1 is used for DEBUG DIGEST */
	3
	4	#include <arpa/inet.h>
	5
	6	/* ================================= Debugging ============================== */
	7
	8	/* Compute the sha1 of string at 's' with 'len' bytes long.
	9	* The SHA1 is then xored againt the string pointed by digest.
	10	* Since xor is commutative, this operation is used in order to
	11	* "add" digests relative to unordered elements.
	12	*
	13	* So digest(a,b,c,d) will be the same of digest(b,a,c,d) */
	14	void xorDigest(unsigned char digest, void ptr, size_t len) {
	15	SHA1_CTX ctx;
	16	unsigned char hash[20], *s = ptr;
	17	int j;
	18
	19	SHA1Init(&ctx);
	20	SHA1Update(&ctx,s,len);
	21	SHA1Final(hash,&ctx);
	22
	23	for (j = 0; j < 20; j++)
	24	digest[j] ^= hash[j];
	25	}
	26
	27	void xorObjectDigest(unsigned char digest, robj o) {
	28	o = getDecodedObject(o);
	29	xorDigest(digest,o->ptr,sdslen(o->ptr));
	30	decrRefCount(o);
	31	}
	32
	33	/* This function instead of just computing the SHA1 and xoring it
	34	* against diget, also perform the digest of "digest" itself and
	35	* replace the old value with the new one.
	36	*
	37	* So the final digest will be:
	38	*
	39	* digest = SHA1(digest xor SHA1(data))
	40	*
	41	* This function is used every time we want to preserve the order so
	42	* that digest(a,b,c,d) will be different than digest(b,c,d,a)
	43	*
	44	* Also note that mixdigest("foo") followed by mixdigest("bar")
	45	* will lead to a different digest compared to "fo", "obar".
	46	*/
	47	void mixDigest(unsigned char digest, void ptr, size_t len) {
	48	SHA1_CTX ctx;
	49	char *s = ptr;
	50
	51	xorDigest(digest,s,len);
	52	SHA1Init(&ctx);
	53	SHA1Update(&ctx,digest,20);
	54	SHA1Final(digest,&ctx);
	55	}
	56
	57	void mixObjectDigest(unsigned char digest, robj o) {
	58	o = getDecodedObject(o);
	59	mixDigest(digest,o->ptr,sdslen(o->ptr));
	60	decrRefCount(o);
	61	}
	62
	63	/* Compute the dataset digest. Since keys, sets elements, hashes elements
	64	* are not ordered, we use a trick: every aggregate digest is the xor
	65	* of the digests of their elements. This way the order will not change
	66	* the result. For list instead we use a feedback entering the output digest
	67	* as input in order to ensure that a different ordered list will result in
	68	* a different digest. */
	69	void computeDatasetDigest(unsigned char *final) {
	70	unsigned char digest[20];
	71	char buf[128];
	72	dictIterator *di = NULL;
	73	dictEntry *de;
	74	int j;
	75	uint32_t aux;
	76
	77	memset(final,0,20); /* Start with a clean result */
	78
	79	for (j = 0; j < server.dbnum; j++) {
	80	redisDb *db = server.db+j;
	81
	82	if (dictSize(db->dict) == 0) continue;
	83	di = dictGetIterator(db->dict);
	84
	85	/* hash the DB id, so the same dataset moved in a different
	86	* DB will lead to a different digest */
	87	aux = htonl(j);
	88	mixDigest(final,&aux,sizeof(aux));
	89
	90	/* Iterate this DB writing every entry */
	91	while((de = dictNext(di)) != NULL) {
	92	sds key;
	93	robj keyobj, o;
	94	time_t expiretime;
	95
	96	memset(digest,0,20); /* This key-val digest */
	97	key = dictGetEntryKey(de);
	98	keyobj = createStringObject(key,sdslen(key));
	99
	100	mixDigest(digest,key,sdslen(key));
	101
	102	/* Make sure the key is loaded if VM is active */
	103	o = lookupKeyRead(db,keyobj);
	104
	105	aux = htonl(o->type);
	106	mixDigest(digest,&aux,sizeof(aux));
	107	expiretime = getExpire(db,keyobj);
	108
	109	/* Save the key and associated value */
	110	if (o->type == REDIS_STRING) {
	111	mixObjectDigest(digest,o);
	112	} else if (o->type == REDIS_LIST) {
	113	listTypeIterator *li = listTypeInitIterator(o,0,REDIS_TAIL);
	114	listTypeEntry entry;
	115	while(listTypeNext(li,&entry)) {
	116	robj *eleobj = listTypeGet(&entry);
	117	mixObjectDigest(digest,eleobj);
	118	decrRefCount(eleobj);
	119	}
	120	listTypeReleaseIterator(li);
	121	} else if (o->type == REDIS_SET) {
	122	setTypeIterator *si = setTypeInitIterator(o);
	123	robj *ele;
	124	while((ele = setTypeNextObject(si)) != NULL) {
	125	xorObjectDigest(digest,ele);
	126	decrRefCount(ele);
	127	}
	128	setTypeReleaseIterator(si);
	129	} else if (o->type == REDIS_ZSET) {
	130	zset *zs = o->ptr;
	131	dictIterator *di = dictGetIterator(zs->dict);
	132	dictEntry *de;
	133
	134	while((de = dictNext(di)) != NULL) {
	135	robj *eleobj = dictGetEntryKey(de);
	136	double *score = dictGetEntryVal(de);
	137	unsigned char eledigest[20];
	138
	139	snprintf(buf,sizeof(buf),"%.17g",*score);
	140	memset(eledigest,0,20);
	141	mixObjectDigest(eledigest,eleobj);
	142	mixDigest(eledigest,buf,strlen(buf));
	143	xorDigest(digest,eledigest,20);
	144	}
	145	dictReleaseIterator(di);
	146	} else if (o->type == REDIS_HASH) {
	147	hashTypeIterator *hi;
	148	robj *obj;
	149
	150	hi = hashTypeInitIterator(o);
	151	while (hashTypeNext(hi) != REDIS_ERR) {
	152	unsigned char eledigest[20];
	153
	154	memset(eledigest,0,20);
	155	obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
	156	mixObjectDigest(eledigest,obj);
	157	decrRefCount(obj);
	158	obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
	159	mixObjectDigest(eledigest,obj);
	160	decrRefCount(obj);
	161	xorDigest(digest,eledigest,20);
	162	}
	163	hashTypeReleaseIterator(hi);
	164	} else {
	165	redisPanic("Unknown object type");
	166	}
	167	/* If the key has an expire, add it to the mix */
	168	if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
	169	/* We can finally xor the key-val digest to the final digest */
	170	xorDigest(final,digest,20);
	171	decrRefCount(keyobj);
	172	}
	173	dictReleaseIterator(di);
	174	}
	175	}
	176
	177	void debugCommand(redisClient *c) {
	178	if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
	179	((char)-1) = 'x';
	180	} else if (!strcasecmp(c->argv[1]->ptr,"flushcache")) {
	181	if (!server.ds_enabled) {
	182	addReplyError(c, "DEBUG FLUSHCACHE called with diskstore off.");
	183	return;
	184	} else if (server.bgsavethread != (pthread_t) -1) {
	185	addReplyError(c, "Can't flush cache while BGSAVE is in progress.");
	186	return;
	187	} else {
	188	/* To flush the whole cache we need to wait for everything to
	189	* be flushed on disk... */
	190	cacheForcePointInTime();
	191	emptyDb();
	192	addReply(c,shared.ok);
	193	return;
	194	}
	195	} else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
	196	if (server.ds_enabled) {
	197	addReply(c,shared.ok);
	198	return;
	199	}
	200	if (rdbSave(server.dbfilename) != REDIS_OK) {
	201	addReply(c,shared.err);
	202	return;
	203	}
	204	emptyDb();
	205	if (rdbLoad(server.dbfilename) != REDIS_OK) {
	206	addReply(c,shared.err);
	207	return;
	208	}
	209	redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
	210	addReply(c,shared.ok);
	211	} else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
	212	emptyDb();
	213	if (loadAppendOnlyFile(server.appendfilename) != REDIS_OK) {
	214	addReply(c,shared.err);
	215	return;
	216	}
	217	redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
	218	addReply(c,shared.ok);
	219	} else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
	220	dictEntry *de;
	221	robj *val;
	222	char *strenc;
	223
	224	if (server.ds_enabled) lookupKeyRead(c->db,c->argv[2]);
	225	if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
	226	addReply(c,shared.nokeyerr);
	227	return;
	228	}
	229	val = dictGetEntryVal(de);
	230	strenc = strEncoding(val->encoding);
	231
	232	addReplyStatusFormat(c,
	233	"Value at:%p refcount:%d "
	234	"encoding:%s serializedlength:%lld "
	235	"lru:%d lru_seconds_idle:%lu",
	236	(void*)val, val->refcount,
	237	strenc, (long long) rdbSavedObjectLen(val),
	238	val->lru, estimateObjectIdleTime(val));
	239	} else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
	240	long keys, j;
	241	robj key, val;
	242	char buf[128];
	243
	244	if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
	245	return;
	246	for (j = 0; j < keys; j++) {
	247	snprintf(buf,sizeof(buf),"key:%lu",j);
	248	key = createStringObject(buf,strlen(buf));
	249	if (lookupKeyRead(c->db,key) != NULL) {
	250	decrRefCount(key);
	251	continue;
	252	}
	253	snprintf(buf,sizeof(buf),"value:%lu",j);
	254	val = createStringObject(buf,strlen(buf));
	255	dbAdd(c->db,key,val);
	256	decrRefCount(key);
	257	}
	258	addReply(c,shared.ok);
	259	} else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
	260	unsigned char digest[20];
	261	sds d = sdsempty();
	262	int j;
	263
	264	computeDatasetDigest(digest);
	265	for (j = 0; j < 20; j++)
	266	d = sdscatprintf(d, "%02x",digest[j]);
	267	addReplyStatus(c,d);
	268	sdsfree(d);
	269	} else {
	270	addReplyError(c,
	271	"Syntax error, try DEBUG [SEGFAULT\|OBJECT <key>\|SWAPIN <key>\|SWAPOUT <key>\|RELOAD]");
	272	}
	273	}
	274
	275	void _redisAssert(char estr, char file, int line) {
	276	redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
	277	redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
	278	#ifdef HAVE_BACKTRACE
	279	redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
	280	((char)-1) = 'x';
	281	#endif
	282	}
	283
	284	void _redisPanic(char msg, char file, int line) {
	285	redisLog(REDIS_WARNING,"------------------------------------------------");
	286	redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
	287	redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
	288	#ifdef HAVE_BACKTRACE
	289	redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
	290	redisLog(REDIS_WARNING,"------------------------------------------------");
	291	((char)-1) = 'x';
	292	#endif
	293	}