Redis源码分析08——服务端

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setlocale(LC_COLLATE,"");   tzset(); /* Populates 'timezone' global. */   zmalloc_set_oom_handler(redisOutOfMemoryHandler);   srand(time(NULL)^getpid());   gettimeofday(&tv,NULL);   char hashseed[16];   //dict的种子   getRandomHexChars(hashseed,sizeof(hashseed));   dictSetHashFunctionSeed((uint8_t*)hashseed);

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void dictSetHashFunctionSeed(uint8_t *seed) {    memcpy(dict_hash_function_seed,seed,sizeof(dict_hash_function_seed));}uint64_t siphash(const uint8_t *in, const size_t inlen, const uint8_t *k);uint64_t siphash_nocase(const uint8_t *in, const size_t inlen, const uint8_t *k);uint64_t dictGenHashFunction(const void *key, int len) {    return siphash(key,len,dict_hash_function_seed);}

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server.sentinel_mode = checkForSentinelMode(argc,argv);int checkForSentinelMode(int argc, char **argv) {    int j;    if (strstr(argv[0],"redis-sentinel") != NULL) return 1;    for (j = 1; j < argc; j++)        if (!strcmp(argv[j],"--sentinel")) return 1;    return 0;}

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if (server.sentinel_mode) {     initSentinelConfig();     initSentinel(); }

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if (strstr(argv[0],"redis-check-rdb") != NULL)       redis_check_rdb_main(argc,argv,NULL);   else if (strstr(argv[0],"redis-check-aof") != NULL)       redis_check_aof_main(argc,argv);

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if (argc >= 2) {        j = 1; /* First option to parse in argv[] */        sds options = sdsempty();        char *configfile = NULL;        /* Handle special options --help and --version */        if (strcmp(argv[1], "-v") == 0 ||            strcmp(argv[1], "--version") == 0) version();        if (strcmp(argv[1], "--help") == 0 ||            strcmp(argv[1], "-h") == 0) usage();        if (strcmp(argv[1], "--test-memory") == 0) {            if (argc == 3) {                memtest(atoi(argv[2]),50);                exit(0);            } else {                fprintf(stderr,"Please specify the amount of memory to test in megabytes.\n");                fprintf(stderr,"Example: ./redis-server --test-memory 4096\n\n");                exit(1);            }        }        /* First argument is the config file name? */        if (argv[j][0] != '-' || argv[j][1] != '-') {            configfile = argv[j];            server.configfile = getAbsolutePath(configfile);            /* Replace the config file in server.exec_argv with             * its absolute path. */            zfree(server.exec_argv[j]);            server.exec_argv[j] = zstrdup(server.configfile);            j++;        }        /* All the other options are parsed and conceptually appended to the         * configuration file. For instance --port 6380 will generate the         * string "port 6380\n" to be parsed after the actual file name         * is parsed, if any. */        while(j != argc) {            if (argv[j][0] == '-' && argv[j][1] == '-') {                /* Option name */                if (!strcmp(argv[j], "--check-rdb")) {                    /* Argument has no options, need to skip for parsing. */                    j++;                    continue;                }                if (sdslen(options)) options = sdscat(options,"\n");                options = sdscat(options,argv[j]+2);                options = sdscat(options," ");            } else {                /* Option argument */                options = sdscatrepr(options,argv[j],strlen(argv[j]));                options = sdscat(options," ");            }            j++;        }        if (server.sentinel_mode && configfile && *configfile == '-') {            serverLog(LL_WARNING,                "Sentinel config from STDIN not allowed.");            serverLog(LL_WARNING,                "Sentinel needs config file on disk to save state.  Exiting...");            exit(1);        }        resetServerSaveParams();        loadServerConfig(configfile,options);        sdsfree(options);    }

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void loadServerConfig(char *filename, char *options) {    sds config = sdsempty();    char buf[CONFIG_MAX_LINE+1];    /* Load the file content */    if (filename) {        FILE *fp;        if (filename[0] == '-' && filename[1] == '\0') {            fp = stdin;        } else {            if ((fp = fopen(filename,"r")) == NULL) {                serverLog(LL_WARNING,                    "Fatal error, can't open config file '%s'", filename);                exit(1);            }        }        while(fgets(buf,CONFIG_MAX_LINE+1,fp) != NULL)            config = sdscat(config,buf);        if (fp != stdin) fclose(fp);    }    /* Append the additional options */    if (options) {        config = sdscat(config,"\n");        config = sdscat(config,options);    }    loadServerConfigFromString(config);    sdsfree(config);}

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void daemonize(void) {    int fd;    if (fork() != 0) exit(0); /* parent exits */    setsid(); /* create a new session */    /* Every output goes to /dev/null. If Redis is daemonized but     * the 'logfile' is set to 'stdout' in the configuration file     * it will not log at all. */    if ((fd = open("/dev/null", O_RDWR, 0)) != -1) {        dup2(fd, STDIN_FILENO);        dup2(fd, STDOUT_FILENO);        dup2(fd, STDERR_FILENO);        if (fd > STDERR_FILENO) close(fd);    }}

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intdaemon_init(const char *pname, int facility){	int		i;	pid_t	pid;	if ( (pid = Fork()) < 0) //创建一个子进程		return (-1);	else if (pid)		_exit(0);			/* parent terminates 父进程退出*/	//子进程继续运行	//此进程是子进程,所以肯定不是组长进程	/* child 1 continues... */	if (setsid() < 0)			/* become session leader 创建会话,成为会话首进程,新的进程组的组长进程*/		return (-1);	Signal(SIGHUP, SIG_IGN); //把挂起信号设置为忽略	if ( (pid = Fork()) < 0) //再创建一个子进程		return (-1);	else if (pid) //父进程退出		_exit(0);			/* child 1 terminates */	//第二个子进程继续运行,因为第二个子进程已经不是会话首进程了,所以永远不会获得控制终端	/* child 2 continues... */	daemon_proc = 1;			/* for err_XXX() functions 再error.c中定义的变量*/	chdir("/");				/* change working directory 调整工作目录到根目录 */	/* close off file descriptors */	for (i = 0; i < MAXFD; i++) //关闭所有文件描述符		close(i);	/* redirect stdin, stdout, and stderr to /dev/null 定义标准输入,标准输出和标准错误到/dev/null */	open("/dev/null", O_RDONLY);	open("/dev/null", O_RDWR);	open("/dev/null", O_RDWR);	openlog(pname, LOG_PID, facility); //打开日志文件	return (0);				/* success 函数运行成功 */}

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signal(SIGHUP, SIG_IGN);signal(SIGPIPE, SIG_IGN);

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void setupSignalHandlers(void) {    struct sigaction act;    /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction is used.     * Otherwise, sa_handler is used. */    sigemptyset(&act.sa_mask);    act.sa_flags = 0;    act.sa_handler = sigShutdownHandler;    sigaction(SIGTERM, &act, NULL);    sigaction(SIGINT, &act, NULL);    return;}

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if (server.syslog_enabled) {      openlog(server.syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT,          server.syslog_facility);  }

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server.hz = server.config_hz;    server.pid = getpid();    server.current_client = NULL;    server.clients = listCreate();    server.clients_index = raxNew();    server.clients_to_close = listCreate();    server.slaves = listCreate();    server.monitors = listCreate();    server.clients_pending_write = listCreate();    server.slaveseldb = -1; /* Force to emit the first SELECT command. */    server.unblocked_clients = listCreate();    server.ready_keys = listCreate();    server.clients_waiting_acks = listCreate();    server.get_ack_from_slaves = 0;    server.clients_paused = 0;    server.system_memory_size = zmalloc_get_memory_size();

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 createSharedObjects();    shared.crlf = createObject(OBJ_STRING,sdsnew("\r\n"));    shared.ok = createObject(OBJ_STRING,sdsnew("+OK\r\n"));    shared.err = createObject(OBJ_STRING,sdsnew("-ERR\r\n"));    shared.emptybulk = createObject(OBJ_STRING,sdsnew("$0\r\n\r\n"));    shared.czero = createObject(OBJ_STRING,sdsnew(":0\r\n"));    shared.cone = createObject(OBJ_STRING,sdsnew(":1\r\n"));    shared.cnegone = createObject(OBJ_STRING,sdsnew(":-1\r\n"));    shared.nullbulk = createObject(OBJ_STRING,sdsnew("$-1\r\n"));    shared.nullmultibulk = createObject(OBJ_STRING,sdsnew("*-1\r\n"));    shared.emptymultibulk = createObject(OBJ_STRING,sdsnew("*0\r\n"));    shared.pong = createObject(OBJ_STRING,sdsnew("+PONG\r\n"));    shared.queued = createObject(OBJ_STRING,sdsnew("+QUEUED\r\n"));    shared.emptyscan = createObject(OBJ_STRING,sdsnew("*2\r\n$1\r\n0\r\n*0\r\n"));    shared.wrongtypeerr = createObject(OBJ_STRING,sdsnew(        "-WRONGTYPE Operation against a key holding the wrong kind of value\r\n"));....

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adjustOpenFilesLimit()

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server.el = aeCreateEventLoop(server.maxclients+CONFIG_FDSET_INCR);    if (server.el == NULL) {        serverLog(LL_WARNING,            "Failed creating the event loop. Error message: '%s'",            strerror(errno));        exit(1);    }    server.db = zmalloc(sizeof(redisDb)*server.dbnum);    /* Open the TCP listening socket for the user commands. */    if (server.port != 0 &&        listenToPort(server.port,server.ipfd,&server.ipfd_count) == C_ERR)        exit(1);    /* Open the listening Unix domain socket. */    if (server.unixsocket != NULL) {        unlink(server.unixsocket); /* don't care if this fails */        server.sofd = anetUnixServer(server.neterr,server.unixsocket,            server.unixsocketperm, server.tcp_backlog);        if (server.sofd == ANET_ERR) {            serverLog(LL_WARNING, "Opening Unix socket: %s", server.neterr);            exit(1);        }        anetNonBlock(NULL,server.sofd);    }

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void evictionPoolAlloc(void) {    struct evictionPoolEntry *ep;    int j;    ep = zmalloc(sizeof(*ep)*EVPOOL_SIZE);    for (j = 0; j < EVPOOL_SIZE; j++) {        ep[j].idle = 0;        ep[j].key = NULL;        ep[j].cached = sdsnewlen(NULL,EVPOOL_CACHED_SDS_SIZE);        ep[j].dbid = 0;    }    EvictionPoolLRU = ep;}

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server.rdb_child_pid = -1;   server.aof_child_pid = -1;   server.rdb_child_type = RDB_CHILD_TYPE_NONE;   server.rdb_bgsave_scheduled = 0;   server.child_info_pipe[0] = -1;   server.child_info_pipe[1] = -1;   server.child_info_data.magic = 0;   aofRewriteBufferReset();   server.aof_buf = sdsempty();   server.lastsave = time(NULL); /* At startup we consider the DB saved. */   server.lastbgsave_try = 0;    /* At startup we never tried to BGSAVE. */   server.rdb_save_time_last = -1;   server.rdb_save_time_start = -1;   server.dirty = 0;

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resetServerStats();    /* A few stats we don't want to reset: server startup time, and peak mem. */server.stat_starttime = time(NULL);server.stat_peak_memory = 0;server.stat_rdb_cow_bytes = 0;server.stat_aof_cow_bytes = 0;server.cron_malloc_stats.zmalloc_used = 0;server.cron_malloc_stats.process_rss = 0;server.cron_malloc_stats.allocator_allocated = 0;server.cron_malloc_stats.allocator_active = 0;server.cron_malloc_stats.allocator_resident = 0;server.lastbgsave_status = C_OK;server.aof_last_write_status = C_OK;server.aof_last_write_errno = 0;server.repl_good_slaves_count = 0;

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/* Create the timer callback, this is our way to process many background * operations incrementally, like clients timeout, eviction of unaccessed * expired keys and so forth. */if (aeCreateTimeEvent(server.el, 1, serverCron, NULL, NULL) == AE_ERR) {    serverPanic("Can't create event loop timers.");    exit(1);}/* Create an event handler for accepting new connections in TCP and Unix * domain sockets. */for (j = 0; j < server.ipfd_count; j++) {    if (aeCreateFileEvent(server.el, server.ipfd[j], AE_READABLE,        acceptTcpHandler,NULL) == AE_ERR)        {            serverPanic(                "Unrecoverable error creating server.ipfd file event.");        }}if (server.sofd > 0 && aeCreateFileEvent(server.el,server.sofd,AE_READABLE,    acceptUnixHandler,NULL) == AE_ERR) serverPanic("Unrecoverable error creating server.sofd file event.");/* Register a readable event for the pipe used to awake the event loop * when a blocked client in a module needs attention. */if (aeCreateFileEvent(server.el, server.module_blocked_pipe[0], AE_READABLE,    moduleBlockedClientPipeReadable,NULL) == AE_ERR) {        serverPanic(            "Error registering the readable event for the module "            "blocked clients subsystem.");}

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void slowlogInit(void) {    server.slowlog = listCreate();    server.slowlog_entry_id = 0;    listSetFreeMethod(server.slowlog,slowlogFreeEntry);}

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/* Background job opcodes */#define BIO_CLOSE_FILE    0 /* Deferred close(2) syscall. */#define BIO_AOF_FSYNC     1 /* Deferred AOF fsync. */#define BIO_LAZY_FREE     2 /* Deferred objects freeing. */#define BIO_NUM_OPS       3

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/* Initialize the background system, spawning the thread. */void bioInit(void) {    pthread_attr_t attr;    pthread_t thread;    size_t stacksize;    int j;    /* Initialization of state vars and objects */    for (j = 0; j < BIO_NUM_OPS; j++) {        pthread_mutex_init(&bio_mutex[j],NULL);        pthread_cond_init(&bio_newjob_cond[j],NULL);        pthread_cond_init(&bio_step_cond[j],NULL);        bio_jobs[j] = listCreate();        bio_pending[j] = 0;    }    /* Set the stack size as by default it may be small in some system */    pthread_attr_init(&attr);    pthread_attr_getstacksize(&attr,&stacksize);    if (!stacksize) stacksize = 1; /* The world is full of Solaris Fixes */    while (stacksize < REDIS_THREAD_STACK_SIZE) stacksize *= 2;    pthread_attr_setstacksize(&attr, stacksize);    /* Ready to spawn our threads. We use the single argument the thread     * function accepts in order to pass the job ID the thread is     * responsible of. */    for (j = 0; j < BIO_NUM_OPS; j++) {        void *arg = (void*)(unsigned long) j;        if (pthread_create(&thread,&attr,bioProcessBackgroundJobs,arg) != 0) {            serverLog(LL_WARNING,"Fatal: Can't initialize Background Jobs.");            exit(1);        }        bio_threads[j] = thread;    }}

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scriptingInit()

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void moduleLoadFromQueue(void) {    listIter li;    listNode *ln;    listRewind(server.loadmodule_queue,&li);    while((ln = listNext(&li))) {        struct moduleLoadQueueEntry *loadmod = ln->value;        if (moduleLoad(loadmod->path,(void **)loadmod->argv,loadmod->argc)            == C_ERR)        {            serverLog(LL_WARNING,                "Can't load module from %s: server aborting",                loadmod->path);            exit(1);        }    }}

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void loadDataFromDisk(void) {    long long start = ustime();    if (server.aof_state == AOF_ON) {        if (loadAppendOnlyFile(server.aof_filename) == C_OK)            serverLog(LL_NOTICE,"DB loaded from append only file: %.3f seconds",(float)(ustime()-start)/1000000);    } else {        rdbSaveInfo rsi = RDB_SAVE_INFO_INIT;        if (rdbLoad(server.rdb_filename,&rsi) == C_OK) {            serverLog(LL_NOTICE,"DB loaded from disk: %.3f seconds",                (float)(ustime()-start)/1000000);            /* Restore the replication ID / offset from the RDB file. */            if (server.masterhost &&                rsi.repl_id_is_set &&                rsi.repl_offset != -1 &&                /* Note that older implementations may save a repl_stream_db                 * of -1 inside the RDB file in a wrong way, see more information                 * in function rdbPopulateSaveInfo. */                rsi.repl_stream_db != -1)            {                memcpy(server.replid,rsi.repl_id,sizeof(server.replid));                server.master_repl_offset = rsi.repl_offset;                /* If we are a slave, create a cached master from this                 * information, in order to allow partial resynchronizations                 * with masters. */                replicationCacheMasterUsingMyself();                selectDb(server.cached_master,rsi.repl_stream_db);            }        } else if (errno != ENOENT) {            serverLog(LL_WARNING,"Fatal error loading the DB: %s. Exiting.",strerror(errno));            exit(1);        }    }}

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aeSetBeforeSleepProc(server.el,beforeSleep);    aeSetAfterSleepProc(server.el,afterSleep);

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void beforeSleep(struct aeEventLoop *eventLoop) {    UNUSED(eventLoop);    /* Call the Redis Cluster before sleep function. Note that this function     * may change the state of Redis Cluster (from ok to fail or vice versa),     * so it's a good idea to call it before serving the unblocked clients     * later in this function. */    if (server.cluster_enabled) clusterBeforeSleep();    /* Run a fast expire cycle (the called function will return     * ASAP if a fast cycle is not needed). */    if (server.active_expire_enabled && server.masterhost == NULL)        activeExpireCycle(ACTIVE_EXPIRE_CYCLE_FAST);    /* Send all the slaves an ACK request if at least one client blocked     * during the previous event loop iteration. */    if (server.get_ack_from_slaves) {        robj *argv[3];        argv[0] = createStringObject("REPLCONF",8);        argv[1] = createStringObject("GETACK",6);        argv[2] = createStringObject("*",1); /* Not used argument. */        replicationFeedSlaves(server.slaves, server.slaveseldb, argv, 3);        decrRefCount(argv[0]);        decrRefCount(argv[1]);        decrRefCount(argv[2]);        server.get_ack_from_slaves = 0;    }    /* Unblock all the clients blocked for synchronous replication     * in WAIT. */    if (listLength(server.clients_waiting_acks))        processClientsWaitingReplicas();    /* Check if there are clients unblocked by modules that implement     * blocking commands. */    moduleHandleBlockedClients();    /* Try to process pending commands for clients that were just unblocked. */    if (listLength(server.unblocked_clients))        processUnblockedClients();    /* Write the AOF buffer on disk */    flushAppendOnlyFile(0);    /* Handle writes with pending output buffers. */    handleClientsWithPendingWrites();    /* Before we are going to sleep, let the threads access the dataset by     * releasing the GIL. Redis main thread will not touch anything at this     * time. */    if (moduleCount()) moduleReleaseGIL();}

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void aeMain(aeEventLoop *eventLoop) {    eventLoop->stop = 0;    while (!eventLoop->stop) {        // 这很重要，写AOF文件在这里进行        if (eventLoop->beforesleep != NULL)            eventLoop->beforesleep(eventLoop);        aeProcessEvents(eventLoop, AE_ALL_EVENTS|AE_CALL_AFTER_SLEEP);    }}//而after函数是在aeProcessEvents函数中//表示睡眠一段时间之后执行        /* After sleep callback. */        if (eventLoop->aftersleep != NULL && flags & AE_CALL_AFTER_SLEEP)            eventLoop->aftersleep(eventLoop);