]> git.saurik.com Git - redis.git/blame - src/debug.c
fix rare condition where 'key' would already be destroyed while is was needed later on
[redis.git] / src / debug.c
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e2641e09 1#include "redis.h"
2#include "sha1.h" /* SHA1 is used for DEBUG DIGEST */
3
3688d7f3 4#include <arpa/inet.h>
5
e2641e09 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) */
14void 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
27void 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 */
47void 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
57void 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. */
69void 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 dict *set = o->ptr;
123 dictIterator *di = dictGetIterator(set);
124 dictEntry *de;
125
126 while((de = dictNext(di)) != NULL) {
127 robj *eleobj = dictGetEntryKey(de);
128
129 xorObjectDigest(digest,eleobj);
130 }
131 dictReleaseIterator(di);
132 } else if (o->type == REDIS_ZSET) {
133 zset *zs = o->ptr;
134 dictIterator *di = dictGetIterator(zs->dict);
135 dictEntry *de;
136
137 while((de = dictNext(di)) != NULL) {
138 robj *eleobj = dictGetEntryKey(de);
139 double *score = dictGetEntryVal(de);
140 unsigned char eledigest[20];
141
142 snprintf(buf,sizeof(buf),"%.17g",*score);
143 memset(eledigest,0,20);
144 mixObjectDigest(eledigest,eleobj);
145 mixDigest(eledigest,buf,strlen(buf));
146 xorDigest(digest,eledigest,20);
147 }
148 dictReleaseIterator(di);
149 } else if (o->type == REDIS_HASH) {
150 hashTypeIterator *hi;
151 robj *obj;
152
153 hi = hashTypeInitIterator(o);
154 while (hashTypeNext(hi) != REDIS_ERR) {
155 unsigned char eledigest[20];
156
157 memset(eledigest,0,20);
158 obj = hashTypeCurrent(hi,REDIS_HASH_KEY);
159 mixObjectDigest(eledigest,obj);
160 decrRefCount(obj);
161 obj = hashTypeCurrent(hi,REDIS_HASH_VALUE);
162 mixObjectDigest(eledigest,obj);
163 decrRefCount(obj);
164 xorDigest(digest,eledigest,20);
165 }
166 hashTypeReleaseIterator(hi);
167 } else {
168 redisPanic("Unknown object type");
169 }
170 /* If the key has an expire, add it to the mix */
171 if (expiretime != -1) xorDigest(digest,"!!expire!!",10);
172 /* We can finally xor the key-val digest to the final digest */
173 xorDigest(final,digest,20);
174 decrRefCount(keyobj);
175 }
176 dictReleaseIterator(di);
177 }
178}
179
180void debugCommand(redisClient *c) {
181 if (!strcasecmp(c->argv[1]->ptr,"segfault")) {
182 *((char*)-1) = 'x';
183 } else if (!strcasecmp(c->argv[1]->ptr,"reload")) {
184 if (rdbSave(server.dbfilename) != REDIS_OK) {
185 addReply(c,shared.err);
186 return;
187 }
188 emptyDb();
189 if (rdbLoad(server.dbfilename) != REDIS_OK) {
190 addReply(c,shared.err);
191 return;
192 }
193 redisLog(REDIS_WARNING,"DB reloaded by DEBUG RELOAD");
194 addReply(c,shared.ok);
195 } else if (!strcasecmp(c->argv[1]->ptr,"loadaof")) {
196 emptyDb();
197 if (loadAppendOnlyFile(server.appendfilename) != REDIS_OK) {
198 addReply(c,shared.err);
199 return;
200 }
201 redisLog(REDIS_WARNING,"Append Only File loaded by DEBUG LOADAOF");
202 addReply(c,shared.ok);
203 } else if (!strcasecmp(c->argv[1]->ptr,"object") && c->argc == 3) {
204 dictEntry *de = dictFind(c->db->dict,c->argv[2]->ptr);
205 robj *val;
206
207 if (!de) {
208 addReply(c,shared.nokeyerr);
209 return;
210 }
211 val = dictGetEntryVal(de);
212 if (!server.vm_enabled || (val->storage == REDIS_VM_MEMORY ||
213 val->storage == REDIS_VM_SWAPPING)) {
214 char *strenc;
215
216 strenc = strEncoding(val->encoding);
217 addReplySds(c,sdscatprintf(sdsempty(),
218 "+Value at:%p refcount:%d "
219 "encoding:%s serializedlength:%lld\r\n",
220 (void*)val, val->refcount,
221 strenc, (long long) rdbSavedObjectLen(val,NULL)));
222 } else {
223 vmpointer *vp = (vmpointer*) val;
224 addReplySds(c,sdscatprintf(sdsempty(),
225 "+Value swapped at: page %llu "
226 "using %llu pages\r\n",
227 (unsigned long long) vp->page,
228 (unsigned long long) vp->usedpages));
229 }
230 } else if (!strcasecmp(c->argv[1]->ptr,"swapin") && c->argc == 3) {
231 lookupKeyRead(c->db,c->argv[2]);
232 addReply(c,shared.ok);
233 } else if (!strcasecmp(c->argv[1]->ptr,"swapout") && c->argc == 3) {
234 dictEntry *de = dictFind(c->db->dict,c->argv[2]->ptr);
235 robj *val;
236 vmpointer *vp;
237
238 if (!server.vm_enabled) {
239 addReplySds(c,sdsnew("-ERR Virtual Memory is disabled\r\n"));
240 return;
241 }
242 if (!de) {
243 addReply(c,shared.nokeyerr);
244 return;
245 }
246 val = dictGetEntryVal(de);
247 /* Swap it */
248 if (val->storage != REDIS_VM_MEMORY) {
249 addReplySds(c,sdsnew("-ERR This key is not in memory\r\n"));
250 } else if (val->refcount != 1) {
251 addReplySds(c,sdsnew("-ERR Object is shared\r\n"));
252 } else if ((vp = vmSwapObjectBlocking(val)) != NULL) {
253 dictGetEntryVal(de) = vp;
254 addReply(c,shared.ok);
255 } else {
256 addReply(c,shared.err);
257 }
258 } else if (!strcasecmp(c->argv[1]->ptr,"populate") && c->argc == 3) {
259 long keys, j;
260 robj *key, *val;
261 char buf[128];
262
263 if (getLongFromObjectOrReply(c, c->argv[2], &keys, NULL) != REDIS_OK)
264 return;
265 for (j = 0; j < keys; j++) {
266 snprintf(buf,sizeof(buf),"key:%lu",j);
267 key = createStringObject(buf,strlen(buf));
268 if (lookupKeyRead(c->db,key) != NULL) {
269 decrRefCount(key);
270 continue;
271 }
272 snprintf(buf,sizeof(buf),"value:%lu",j);
273 val = createStringObject(buf,strlen(buf));
274 dbAdd(c->db,key,val);
275 decrRefCount(key);
276 }
277 addReply(c,shared.ok);
278 } else if (!strcasecmp(c->argv[1]->ptr,"digest") && c->argc == 2) {
279 unsigned char digest[20];
280 sds d = sdsnew("+");
281 int j;
282
283 computeDatasetDigest(digest);
284 for (j = 0; j < 20; j++)
285 d = sdscatprintf(d, "%02x",digest[j]);
286
287 d = sdscatlen(d,"\r\n",2);
288 addReplySds(c,d);
289 } else {
290 addReplySds(c,sdsnew(
291 "-ERR Syntax error, try DEBUG [SEGFAULT|OBJECT <key>|SWAPIN <key>|SWAPOUT <key>|RELOAD]\r\n"));
292 }
293}
294
295void _redisAssert(char *estr, char *file, int line) {
296 redisLog(REDIS_WARNING,"=== ASSERTION FAILED ===");
297 redisLog(REDIS_WARNING,"==> %s:%d '%s' is not true",file,line,estr);
298#ifdef HAVE_BACKTRACE
299 redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
300 *((char*)-1) = 'x';
301#endif
302}
303
304void _redisPanic(char *msg, char *file, int line) {
305 redisLog(REDIS_WARNING,"!!! Software Failure. Press left mouse button to continue");
306 redisLog(REDIS_WARNING,"Guru Meditation: %s #%s:%d",msg,file,line);
307#ifdef HAVE_BACKTRACE
308 redisLog(REDIS_WARNING,"(forcing SIGSEGV in order to print the stack trace)");
309 *((char*)-1) = 'x';
310#endif
311}