【redis6.0.6】redis源码慢慢学，慢慢看 -- 第四天：提纲掣领main函数（server）

#ifdef REDIS_TEST
    if (argc == 3 && !strcasecmp(argv[1], "test")) {
        if (!strcasecmp(argv[2], "ziplist")) {
            return ziplistTest(argc, argv);
        } else if (!strcasecmp(argv[2], "quicklist")) {
            quicklistTest(argc, argv);
        } else if (!strcasecmp(argv[2], "intset")) {
            return intsetTest(argc, argv);
        } else if (!strcasecmp(argv[2], "zipmap")) {
            return zipmapTest(argc, argv);
        } else if (!strcasecmp(argv[2], "sha1test")) {
            return sha1Test(argc, argv);
        } else if (!strcasecmp(argv[2], "util")) {
            return utilTest(argc, argv);
        } else if (!strcasecmp(argv[2], "endianconv")) {
            return endianconvTest(argc, argv);
        } else if (!strcasecmp(argv[2], "crc64")) {
            return crc64Test(argc, argv);
        } else if (!strcasecmp(argv[2], "zmalloc")) {
            return zmalloc_test(argc, argv);
        }

        return -1; /* test not found */
    }
#endif

#ifdef INIT_SETPROCTITLE_REPLACEMENT
    spt_init(argc, argv);
#endif

	setlocale(LC_COLLATE,"");	//更改字符编码
    tzset(); /* Populates 'timezone' global. */
    zmalloc_set_oom_handler(redisOutOfMemoryHandler);	//oom时的处理,主要是内存不足时，将需要的memory的值打印出来
    srand(time(NULL)^getpid());	//    根据当前时间和pid获取随机值的
    gettimeofday(&tv,NULL);		// 1970年1月1日到现在的时间
    crc64_init();

	//哈希种子
	uint8_t hashseed[16];
    getRandomBytes(hashseed,sizeof(hashseed));
    dictSetHashFunctionSeed(hashseed);
	
	 // 检查服务器是否以 Sentinel 模式启动
    server.sentinel_mode = checkForSentinelMode(argc,argv);

	// 初始化服务器
    initServerConfig();
    ACLInit(); /* The ACL subsystem must be initialized ASAP because the
                  basic networking code and client creation depends on it. */
    moduleInitModulesSystem();
    tlsInit();

	/* Store the executable path and arguments in a safe place in order
     * to be able to restart the server later. */
    server.executable = getAbsolutePath(argv[0]);
    server.exec_argv = zmalloc(sizeof(char*)*(argc+1));
    server.exec_argv[argc] = NULL;
    for (j = 0; j < argc; j++) server.exec_argv[j] = zstrdup(argv[j]);

	// 如果服务器以 Sentinel 模式启动，那么进行 Sentinel 功能相关的初始化
    // 并为要监视的主服务器创建一些相应的数据结构
    if (server.sentinel_mode) {
        initSentinelConfig();
        initSentinel();
    }

	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);

    //检查用户是否指定了配置文件，或者配置选项
	if (argc >= 2) {
        j = 1; /* First option to parse in argv[] */
        sds options = sdsempty();
        char *configfile = NULL;

	//处理特殊选项 -h 、-v 和 --test-memory
        /* 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 4096nn");
                exit(1);
            }
        }

// 如果第一个参数（argv[1]）不是以 "--" 开头，那么它应该是一个配置文件
 		 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++;
        }

		// 对用户给定的其余选项进行分析，并将分析所得的字符串追加稍后载入的配置文件的内容之后
		// 比如 --port 6380 会被分析为 "port 6380n"
		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();	 // 重置保存条件
	        loadServerConfig(configfile,options);	// 载入配置文件， options 是前面分析出的给定选项
	        sdsfree(options);
	   }

    serverLog(LL_WARNING, "oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo");
    serverLog(LL_WARNING,
        "Redis version=%s, bits=%d, commit=%s, modified=%d, pid=%d, just started",
            REDIS_VERSION,
            (sizeof(long) == 8) ? 64 : 32,
            redisGitSHA1(),
            strtol(redisGitDirty(),NULL,10) > 0,
            (int)getpid());
 
    if (argc == 1) {
        serverLog(LL_WARNING, "Warning: no config file specified, using the default config. In order to specify a config file use %s /path/to/%s.conf", argv[0], server.sentinel_mode ? "sentinel" : "redis");
    } else {
        serverLog(LL_WARNING, "Configuration loaded");
    }
 
  
    server.supervised = redisIsSupervised(server.supervised_mode);
    int background = server.daemonize && !server.supervised;
    if (background) daemonize();

	server.supervised = redisIsSupervised(server.supervised_mode);
    int background = server.daemonize && !server.supervised;
    if (background) daemonize();

    //sever端的初始化
    initServer();

    // 设置进程的title
    if (background || server.pidfile) createPidFile();
    redisSetProcTitle(argv[0]);
    redisAsciiArt();
    checkTcpBacklogSettings();

// 如果服务器不是运行在 SENTINEL 模式，那么执行以下代码
if (!server.sentinel_mode) {
        /* Things not needed when running in Sentinel mode. */
        serverLog(LL_WARNING,"Server initialized");	
    #ifdef __linux__
        linuxMemoryWarnings();	// 打印内存警告
    #endif
        moduleLoadFromQueue();
        ACLLoadUsersAtStartup();
        InitServerLast();
        loadDataFromDisk();	// 从 AOF 文件或者 RDB 文件中载入数据
        if (server.cluster_enabled) {	// 启动集群？
            if (verifyClusterConfigWithData() == C_ERR) {
                serverLog(LL_WARNING,
                    "You can't have keys in a DB different than DB 0 when in "
                    "Cluster mode. Exiting.");
                exit(1);
            }
        }
        if (server.ipfd_count > 0 || server.tlsfd_count > 0)
            serverLog(LL_NOTICE,"Ready to accept connections");
        if (server.sofd > 0)
            serverLog(LL_NOTICE,"The server is now ready to accept connections at %s", server.unixsocket);
        if (server.supervised_mode == SUPERVISED_SYSTEMD) {
            if (!server.masterhost) {
                redisCommunicateSystemd("STATUS=Ready to accept connectionsn");
                redisCommunicateSystemd("READY=1n");
            } else {
                redisCommunicateSystemd("STATUS=Waiting for MASTER <-> REPLICA syncn");
            }
        }
    } else {
        InitServerLast();
        sentinelIsRunning();	        // 检测sentinel的配置是否有效
        if (server.supervised_mode == SUPERVISED_SYSTEMD) {
            redisCommunicateSystemd("STATUS=Ready to accept connectionsn");
            redisCommunicateSystemd("READY=1n");
        }
    }

    // 检查不正常的 maxmemory 配置
    if (server.maxmemory > 0 && server.maxmemory < 1024*1024) {
        serverLog(LL_WARNING,"WARNING: You specified a maxmemory value that is less than 1MB (current value is %llu bytes). Are you sure this is what you really want?", server.maxmemory);
    }

 // 运行事件处理器，一直到服务器关闭为止
    redisSetCpuAffinity(server.server_cpulist);
    aeMain(server.el);	
    aeDeleteEventLoop(server.el);	// 服务器关闭，停止事件循环
    return 0;
}