本文主要是介绍漫话Redis源码之二十九，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
这里主要讲rdb的一些check信息，不是咱们缕清逻辑的重点，不想看的话，可以跳过：
struct {rio *rio;robj *key; /* Current key we are reading. */int key_type; /* Current key type if != -1. */unsigned long keys; /* Number of keys processed. */unsigned long expires; /* Number of keys with an expire. */unsigned long already_expired; /* Number of keys already expired. */int doing; /* The state while reading the RDB. */int error_set; /* True if error is populated. */char error[1024];
} rdbstate;/* At every loading step try to remember what we were about to do, so that* we can log this information when an error is encountered. */
#define RDB_CHECK_DOING_START 0
#define RDB_CHECK_DOING_READ_TYPE 1
#define RDB_CHECK_DOING_READ_EXPIRE 2
#define RDB_CHECK_DOING_READ_KEY 3
#define RDB_CHECK_DOING_READ_OBJECT_VALUE 4
#define RDB_CHECK_DOING_CHECK_SUM 5
#define RDB_CHECK_DOING_READ_LEN 6
#define RDB_CHECK_DOING_READ_AUX 7
#define RDB_CHECK_DOING_READ_MODULE_AUX 8char *rdb_check_doing_string[] = {"start","read-type","read-expire","read-key","read-object-value","check-sum","read-len","read-aux","read-module-aux"
};char *rdb_type_string[] = {"string","list-linked","set-hashtable","zset-v1","hash-hashtable","zset-v2","module-value","","","hash-zipmap","list-ziplist","set-intset","zset-ziplist","hash-ziplist","quicklist","stream"
};/* Show a few stats collected into 'rdbstate' */
void rdbShowGenericInfo(void) {printf("[info] %lu keys read\n", rdbstate.keys);printf("[info] %lu expires\n", rdbstate.expires);printf("[info] %lu already expired\n", rdbstate.already_expired);
}/* Called on RDB errors. Provides details about the RDB and the offset* we were when the error was detected. */
void rdbCheckError(const char *fmt, ...) {char msg[1024];va_list ap;va_start(ap, fmt);vsnprintf(msg, sizeof(msg), fmt, ap);va_end(ap);printf("--- RDB ERROR DETECTED ---\n");printf("[offset %llu] %s\n",(unsigned long long) (rdbstate.rio ?rdbstate.rio->processed_bytes : 0), msg);printf("[additional info] While doing: %s\n",rdb_check_doing_string[rdbstate.doing]);if (rdbstate.key)printf("[additional info] Reading key '%s'\n",(char*)rdbstate.key->ptr);if (rdbstate.key_type != -1)printf("[additional info] Reading type %d (%s)\n",rdbstate.key_type,((unsigned)rdbstate.key_type <sizeof(rdb_type_string)/sizeof(char*)) ?rdb_type_string[rdbstate.key_type] : "unknown");rdbShowGenericInfo();
}/* Print informations during RDB checking. */
void rdbCheckInfo(const char *fmt, ...) {char msg[1024];va_list ap;va_start(ap, fmt);vsnprintf(msg, sizeof(msg), fmt, ap);va_end(ap);printf("[offset %llu] %s\n",(unsigned long long) (rdbstate.rio ?rdbstate.rio->processed_bytes : 0), msg);
}/* Used inside rdb.c in order to log specific errors happening inside* the RDB loading internals. */
void rdbCheckSetError(const char *fmt, ...) {va_list ap;va_start(ap, fmt);vsnprintf(rdbstate.error, sizeof(rdbstate.error), fmt, ap);va_end(ap);rdbstate.error_set = 1;
}/* During RDB check we setup a special signal handler for memory violations* and similar conditions, so that we can log the offending part of the RDB* if the crash is due to broken content. */
void rdbCheckHandleCrash(int sig, siginfo_t *info, void *secret) {UNUSED(sig);UNUSED(info);UNUSED(secret);rdbCheckError("Server crash checking the specified RDB file!");exit(1);
}void rdbCheckSetupSignals(void) {struct sigaction act;sigemptyset(&act.sa_mask);act.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;act.sa_sigaction = rdbCheckHandleCrash;sigaction(SIGSEGV, &act, NULL);sigaction(SIGBUS, &act, NULL);sigaction(SIGFPE, &act, NULL);sigaction(SIGILL, &act, NULL);sigaction(SIGABRT, &act, NULL);
}/* Check the specified RDB file. Return 0 if the RDB looks sane, otherwise* 1 is returned.* The file is specified as a filename in 'rdbfilename' if 'fp' is not NULL,* otherwise the already open file 'fp' is checked. */
int redis_check_rdb(char *rdbfilename, FILE *fp) {uint64_t dbid;int type, rdbver;char buf[1024];long long expiretime, now = mstime();static rio rdb; /* Pointed by global struct riostate. */int closefile = (fp == NULL);if (fp == NULL && (fp = fopen(rdbfilename,"r")) == NULL) return 1;startLoadingFile(fp, rdbfilename, RDBFLAGS_NONE);rioInitWithFile(&rdb,fp);rdbstate.rio = &rdb;rdb.update_cksum = rdbLoadProgressCallback;if (rioRead(&rdb,buf,9) == 0) goto eoferr;buf[9] = '\0';if (memcmp(buf,"REDIS",5) != 0) {rdbCheckError("Wrong signature trying to load DB from file");goto err;}rdbver = atoi(buf+5);if (rdbver < 1 || rdbver > RDB_VERSION) {rdbCheckError("Can't handle RDB format version %d",rdbver);goto err;}expiretime = -1;while(1) {robj *key, *val;/* Read type. */rdbstate.doing = RDB_CHECK_DOING_READ_TYPE;if ((type = rdbLoadType(&rdb)) == -1) goto eoferr;/* Handle special types. */if (type == RDB_OPCODE_EXPIRETIME) {rdbstate.doing = RDB_CHECK_DOING_READ_EXPIRE;/* EXPIRETIME: load an expire associated with the next key* to load. Note that after loading an expire we need to* load the actual type, and continue. */expiretime = rdbLoadTime(&rdb);expiretime *= 1000;if (rioGetReadError(&rdb)) goto eoferr;continue; /* Read next opcode. */} else if (type == RDB_OPCODE_EXPIRETIME_MS) {/* EXPIRETIME_MS: milliseconds precision expire times introduced* with RDB v3. Like EXPIRETIME but no with more precision. */rdbstate.doing = RDB_CHECK_DOING_READ_EXPIRE;expiretime = rdbLoadMillisecondTime(&rdb, rdbver);if (rioGetReadError(&rdb)) goto eoferr;continue; /* Read next opcode. */} else if (type == RDB_OPCODE_FREQ) {/* FREQ: LFU frequency. */uint8_t byte;if (rioRead(&rdb,&byte,1) == 0) goto eoferr;continue; /* Read next opcode. */} else if (type == RDB_OPCODE_IDLE) {/* IDLE: LRU idle time. */if (rdbLoadLen(&rdb,NULL) == RDB_LENERR) goto eoferr;continue; /* Read next opcode. */} else if (type == RDB_OPCODE_EOF) {/* EOF: End of file, exit the main loop. */break;} else if (type == RDB_OPCODE_SELECTDB) {/* SELECTDB: Select the specified database. */rdbstate.doing = RDB_CHECK_DOING_READ_LEN;if ((dbid = rdbLoadLen(&rdb,NULL)) == RDB_LENERR)goto eoferr;rdbCheckInfo("Selecting DB ID %llu", (unsigned long long)dbid);continue; /* Read type again. */} else if (type == RDB_OPCODE_RESIZEDB) {/* RESIZEDB: Hint about the size of the keys in the currently* selected data base, in order to avoid useless rehashing. */uint64_t db_size, expires_size;rdbstate.doing = RDB_CHECK_DOING_READ_LEN;if ((db_size = rdbLoadLen(&rdb,NULL)) == RDB_LENERR)goto eoferr;if ((expires_size = rdbLoadLen(&rdb,NULL)) == RDB_LENERR)goto eoferr;continue; /* Read type again. */} else if (type == RDB_OPCODE_AUX) {/* AUX: generic string-string fields. Use to add state to RDB* which is backward compatible. Implementations of RDB loading* are requierd to skip AUX fields they don't understand.** An AUX field is composed of two strings: key and value. */robj *auxkey, *auxval;rdbstate.doing = RDB_CHECK_DOING_READ_AUX;if ((auxkey = rdbLoadStringObject(&rdb)) == NULL) goto eoferr;if ((auxval = rdbLoadStringObject(&rdb)) == NULL) goto eoferr;rdbCheckInfo("AUX FIELD %s = '%s'",(char*)auxkey->ptr, (char*)auxval->ptr);decrRefCount(auxkey);decrRefCount(auxval);continue; /* Read type again. */} else if (type == RDB_OPCODE_MODULE_AUX) {/* AUX: Auxiliary data for modules. */uint64_t moduleid, when_opcode, when;rdbstate.doing = RDB_CHECK_DOING_READ_MODULE_AUX;if ((moduleid = rdbLoadLen(&rdb,NULL)) == RDB_LENERR) goto eoferr;if ((when_opcode = rdbLoadLen(&rdb,NULL)) == RDB_LENERR) goto eoferr;if ((when = rdbLoadLen(&rdb,NULL)) == RDB_LENERR) goto eoferr;char name[10];moduleTypeNameByID(name,moduleid);rdbCheckInfo("MODULE AUX for: %s", name);robj *o = rdbLoadCheckModuleValue(&rdb,name);decrRefCount(o);continue; /* Read type again. */} else {if (!rdbIsObjectType(type)) {rdbCheckError("Invalid object type: %d", type);goto err;}rdbstate.key_type = type;}/* Read key */rdbstate.doing = RDB_CHECK_DOING_READ_KEY;if ((key = rdbLoadStringObject(&rdb)) == NULL) goto eoferr;rdbstate.key = key;rdbstate.keys++;/* Read value */rdbstate.doing = RDB_CHECK_DOING_READ_OBJECT_VALUE;if ((val = rdbLoadObject(type,&rdb,key->ptr,NULL)) == NULL) goto eoferr;/* Check if the key already expired. */if (expiretime != -1 && expiretime < now)rdbstate.already_expired++;if (expiretime != -1) rdbstate.expires++;rdbstate.key = NULL;decrRefCount(key);decrRefCount(val);rdbstate.key_type = -1;expiretime = -1;}/* Verify the checksum if RDB version is >= 5 */if (rdbver >= 5 && server.rdb_checksum) {uint64_t cksum, expected = rdb.cksum;rdbstate.doing = RDB_CHECK_DOING_CHECK_SUM;if (rioRead(&rdb,&cksum,8) == 0) goto eoferr;memrev64ifbe(&cksum);if (cksum == 0) {rdbCheckInfo("RDB file was saved with checksum disabled: no check performed.");} else if (cksum != expected) {rdbCheckError("RDB CRC error");goto err;} else {rdbCheckInfo("Checksum OK");}}if (closefile) fclose(fp);stopLoading(1);return 0;eoferr: /* unexpected end of file is handled here with a fatal exit */if (rdbstate.error_set) {rdbCheckError(rdbstate.error);} else {rdbCheckError("Unexpected EOF reading RDB file");}
err:if (closefile) fclose(fp);stopLoading(0);return 1;
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