xref: /redis-3.2.3/src/debug.c (revision 86de66e3)
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             long long expiretime;
95 
96             memset(digest,0,20); /* This key-val digest */
97             key = dictGetKey(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 = dictGetVal(de);
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                 unsigned char eledigest[20];
131 
132                 if (o->encoding == REDIS_ENCODING_ZIPLIST) {
133                     unsigned char *zl = o->ptr;
134                     unsigned char *eptr, *sptr;
135                     unsigned char *vstr;
136                     unsigned int vlen;
137                     long long vll;
138                     double score;
139 
140                     eptr = ziplistIndex(zl,0);
141                     redisAssert(eptr != NULL);
142                     sptr = ziplistNext(zl,eptr);
143                     redisAssert(sptr != NULL);
144 
145                     while (eptr != NULL) {
146                         redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
147                         score = zzlGetScore(sptr);
148 
149                         memset(eledigest,0,20);
150                         if (vstr != NULL) {
151                             mixDigest(eledigest,vstr,vlen);
152                         } else {
153                             ll2string(buf,sizeof(buf),vll);
154                             mixDigest(eledigest,buf,strlen(buf));
155                         }
156 
157                         snprintf(buf,sizeof(buf),"%.17g",score);
158                         mixDigest(eledigest,buf,strlen(buf));
159                         xorDigest(digest,eledigest,20);
160                         zzlNext(zl,&eptr,&sptr);
161                     }
162                 } else if (o->encoding == REDIS_ENCODING_SKIPLIST) {
163                     zset *zs = o->ptr;
164                     dictIterator *di = dictGetIterator(zs->dict);
165                     dictEntry *de;
166 
167                     while((de = dictNext(di)) != NULL) {
168                         robj *eleobj = dictGetKey(de);
169                         double *score = dictGetVal(de);
170 
171                         snprintf(buf,sizeof(buf),"%.17g",*score);
172                         memset(eledigest,0,20);
173                         mixObjectDigest(eledigest,eleobj);
174                         mixDigest(eledigest,buf,strlen(buf));
175                         xorDigest(digest,eledigest,20);
176                     }
177                     dictReleaseIterator(di);
178                 } else {
179                     redisPanic("Unknown sorted set encoding");
180                 }
181             } else if (o->type == REDIS_HASH) {
182                 hashTypeIterator *hi;
183                 robj *obj;
184 
185                 hi = hashTypeInitIterator(o);
186                 while (hashTypeNext(hi) != REDIS_ERR) {
187                     unsigned char eledigest[20];
188 
189                     memset(eledigest,0,20);
190                     obj = hashTypeCurrentObject(hi,REDIS_HASH_KEY);
191                     mixObjectDigest(eledigest,obj);
192                     decrRefCount(obj);
193                     obj = hashTypeCurrentObject(hi,REDIS_HASH_VALUE);
194                     mixObjectDigest(eledigest,obj);
195                     decrRefCount(obj);
196                     xorDigest(digest,eledigest,20);
197                 }
198                 hashTypeReleaseIterator(hi);
199             } else {
200                 redisPanic("Unknown object type");
201             }
202             /* If the key has an expire, add it to the mix */
203             if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
204             /* We can finally xor the key-val digest to the final digest */
205             xorDigest(final,digest,20);
206             decrRefCount(keyobj);
207         }
208         dictReleaseIterator(di);
209     }
210 }
211 
212 void debugCommand(redisClient *c) {
213     if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
214         *((char*)-1) = 'x';
215     } else if (!strcasecmp(c->argv[1]->ptr,"assert")) {
216         if (c->argc >= 3) c->argv[2] = tryObjectEncoding(c->argv[2]);
217         redisAssertWithInfo(c,c->argv[0],1 == 2);
218     } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
219         if (rdbSave(server.dbfilename) != REDIS_OK) {
220             addReply(c,shared.err);
221             return;
222         }
223         emptyDb();
224         if (rdbLoad(server.dbfilename) != REDIS_OK) {
225             addReplyError(c,"Error trying to load the RDB dump");
226             return;
227         }
228         redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
229         addReply(c,shared.ok);
230     } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
231         emptyDb();
232         if (loadAppendOnlyFile(server.appendfilename) != REDIS_OK) {
233             addReply(c,shared.err);
234             return;
235         }
236         redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
237         addReply(c,shared.ok);
238     } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
239         dictEntry *de;
240         robj *val;
241         char *strenc;
242 
243         if ((de = dictFind(c->db->dict,c->argv[2]->ptr)) == NULL) {
244             addReply(c,shared.nokeyerr);
245             return;
246         }
247         val = dictGetVal(de);
248         strenc = strEncoding(val->encoding);
249 
250         addReplyStatusFormat(c,
251             "Value at:%p refcount:%d "
252             "encoding:%s serializedlength:%lld "
253             "lru:%d lru_seconds_idle:%lu",
254             (void*)val, val->refcount,
255             strenc, (long long) rdbSavedObjectLen(val),
256             val->lru, estimateObjectIdleTime(val));
257     } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
258         long keys, j;
259         robj *key, *val;
260         char buf[128];
261 
262         if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
263             return;
264         for (j = 0; j < keys; j++) {
265             snprintf(buf,sizeof(buf),"key:%lu",j);
266             key = createStringObject(buf,strlen(buf));
267             if (lookupKeyRead(c->db,key) != NULL) {
268                 decrRefCount(key);
269                 continue;
270             }
271             snprintf(buf,sizeof(buf),"value:%lu",j);
272             val = createStringObject(buf,strlen(buf));
273             dbAdd(c->db,key,val);
274             decrRefCount(key);
275         }
276         addReply(c,shared.ok);
277     } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
278         unsigned char digest[20];
279         sds d = sdsempty();
280         int j;
281 
282         computeDatasetDigest(digest);
283         for (j = 0; j < 20; j++)
284             d = sdscatprintf(d, "%02x",digest[j]);
285         addReplyStatus(c,d);
286         sdsfree(d);
287     } else if (!strcasecmp(c->argv[1]->ptr,"sleep") && c->argc == 3) {
288         double dtime = strtod(c->argv[2]->ptr,NULL);
289         long long utime = dtime*1000000;
290 
291         usleep(utime);
292         addReply(c,shared.ok);
293     } else {
294         addReplyError(c,
295             "Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]");
296     }
297 }
298 
299 void _redisAssert(char *estr, char *file, int line) {
300     bugReportStart();
301     redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
302     redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
303 #ifdef HAVE_BACKTRACE
304     server.assert_failed = estr;
305     server.assert_file = file;
306     server.assert_line = line;
307     redisLog(REDIS_WARNING,"(forcing SIGSEGV to print the bug report.)");
308     *((char*)-1) = 'x';
309 #endif
310 }
311 
312 void _redisAssertPrintClientInfo(redisClient *c) {
313     int j;
314 
315     bugReportStart();
316     redisLog(REDIS_WARNING,"=== ASSERTION FAILED CLIENT CONTEXT ===");
317     redisLog(REDIS_WARNING,"client->flags = %d", c->flags);
318     redisLog(REDIS_WARNING,"client->fd = %d", c->fd);
319     redisLog(REDIS_WARNING,"client->argc = %d", c->argc);
320     for (j=0; j < c->argc; j++) {
321         char buf[128];
322         char *arg;
323 
324         if (c->argv[j]->type == REDIS_STRING &&
325             c->argv[j]->encoding == REDIS_ENCODING_RAW)
326         {
327             arg = (char*) c->argv[j]->ptr;
328         } else {
329             snprintf(buf,sizeof(buf),"Object type: %d, encoding: %d",
330                 c->argv[j]->type, c->argv[j]->encoding);
331             arg = buf;
332         }
333         redisLog(REDIS_WARNING,"client->argv[%d] = \"%s\" (refcount: %d)",
334             j, arg, c->argv[j]->refcount);
335     }
336 }
337 
338 void _redisAssertPrintObject(robj *o) {
339     bugReportStart();
340     redisLog(REDIS_WARNING,"=== ASSERTION FAILED OBJECT CONTEXT ===");
341     redisLog(REDIS_WARNING,"Object type: %d", o->type);
342     redisLog(REDIS_WARNING,"Object encoding: %d", o->encoding);
343     redisLog(REDIS_WARNING,"Object refcount: %d", o->refcount);
344     if (o->type == REDIS_STRING && o->encoding == REDIS_ENCODING_RAW) {
345         redisLog(REDIS_WARNING,"Object raw string len: %d", sdslen(o->ptr));
346         if (sdslen(o->ptr) < 4096)
347             redisLog(REDIS_WARNING,"Object raw string content: \"%s\"", (char*)o->ptr);
348     }
349 }
350 
351 void _redisAssertWithInfo(redisClient *c, robj *o, char *estr, char *file, int line) {
352     if (c) _redisAssertPrintClientInfo(c);
353     if (o) _redisAssertPrintObject(o);
354     _redisAssert(estr,file,line);
355 }
356 
357 void _redisPanic(char *msg, char *file, int line) {
358     bugReportStart();
359     redisLog(REDIS_WARNING,"------------------------------------------------");
360     redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
361     redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
362 #ifdef HAVE_BACKTRACE
363     redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
364     redisLog(REDIS_WARNING,"------------------------------------------------");
365     *((char*)-1) = 'x';
366 #endif
367 }
368