void evalGenericCommand(client *c, int evalsha) {
    lua_State *lua = server.lua;
    char funcname[43];
    long long numkeys;
    long long initial_server_dirty = server.dirty;
    int delhook = 0, err;

    /* When we replicate whole scripts, we want the same PRNG sequence at
     * every call so that our PRNG is not affected by external state. */
    redisSrand48(0);

    /* We set this flag to zero to remember that so far no random command
     * was called. This way we can allow the user to call commands like
     * SRANDMEMBER or RANDOMKEY from Lua scripts as far as no write command
     * is called (otherwise the replication and AOF would end with non
     * deterministic sequences).
     *
     * Thanks to this flag we'll raise an error every time a write command
     * is called after a random command was used. */
    server.lua_random_dirty = 0;
    server.lua_write_dirty = 0;
    server.lua_replicate_commands = server.lua_always_replicate_commands;
    server.lua_multi_emitted = 0;
    server.lua_repl = PROPAGATE_AOF|PROPAGATE_REPL;

    /* Get the number of arguments that are keys */
    if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != C_OK)
        return;
    if (numkeys > (c->argc - 3)) {
        addReplyError(c,"Number of keys can't be greater than number of args");
        return;
    } else if (numkeys < 0) {
        addReplyError(c,"Number of keys can't be negative");
        return;
    }

    /* We obtain the script SHA1, then check if this function is already
     * defined into the Lua state */
    funcname[0] = 'f';
    funcname[1] = '_';
    if (!evalsha) {
        /* Hash the code if this is an EVAL call */
        sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
    } else {
        /* We already have the SHA if it is an EVALSHA */
        int j;
        char *sha = c->argv[1]->ptr;

        /* Convert to lowercase. We don't use tolower since the function
         * managed to always show up in the profiler output consuming
         * a non trivial amount of time. */
        for (j = 0; j < 40; j++)
            funcname[j+2] = (sha[j] >= 'A' && sha[j] <= 'Z') ?
                sha[j]+('a'-'A') : sha[j];
        funcname[42] = '\0';
    }

    /* Push the pcall error handler function on the stack. */
    lua_getglobal(lua, "__redis__err__handler");

    /* Try to lookup the Lua function */
    lua_getglobal(lua, funcname);
    if (lua_isnil(lua,-1)) {
        lua_pop(lua,1); /* remove the nil from the stack */
        /* Function not defined... let's define it if we have the
         * body of the function. If this is an EVALSHA call we can just
         * return an error. */
        if (evalsha) {
            lua_pop(lua,1); /* remove the error handler from the stack. */
            addReply(c, shared.noscripterr);
            return;
        }
        if (luaCreateFunction(c,lua,c->argv[1]) == NULL) {
            lua_pop(lua,1); /* remove the error handler from the stack. */
            /* The error is sent to the client by luaCreateFunction()
             * itself when it returns NULL. */
            return;
        }
        /* Now the following is guaranteed to return non nil */
        lua_getglobal(lua, funcname);
        serverAssert(!lua_isnil(lua,-1));
    }

    /* Populate the argv and keys table accordingly to the arguments that
     * EVAL received. */
    luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
    luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);

    /* Set a hook in order to be able to stop the script execution if it
     * is running for too much time.
     * We set the hook only if the time limit is enabled as the hook will
     * make the Lua script execution slower.
     *
     * If we are debugging, we set instead a "line" hook so that the
     * debugger is call-back at every line executed by the script. */
    server.lua_caller = c;
    server.lua_cur_script = funcname + 2;
    server.lua_time_start = mstime();
    server.lua_kill = 0;
    if (server.lua_time_limit > 0 && ldb.active == 0) {
        lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
        delhook = 1;
    } else if (ldb.active) {
        lua_sethook(server.lua,luaLdbLineHook,LUA_MASKLINE|LUA_MASKCOUNT,100000);
        delhook = 1;
    }

    prepareLuaClient();

    /* At this point whether this script was never seen before or if it was
     * already defined, we can call it. We have zero arguments and expect
     * a single return value. */
    err = lua_pcall(lua,0,1,-2);

    resetLuaClient();

    /* Perform some cleanup that we need to do both on error and success. */
    if (delhook) lua_sethook(lua,NULL,0,0); /* Disable hook */
    if (server.lua_timedout) {
        server.lua_timedout = 0;
        /* Restore the client that was protected when the script timeout
         * was detected. */
        unprotectClient(c);
        if (server.masterhost && server.master)
            queueClientForReprocessing(server.master);
    }
    server.lua_caller = NULL;
    server.lua_cur_script = NULL;

    /* Call the Lua garbage collector from time to time to avoid a
     * full cycle performed by Lua, which adds too latency.
     *
     * The call is performed every LUA_GC_CYCLE_PERIOD executed commands
     * (and for LUA_GC_CYCLE_PERIOD collection steps) because calling it
     * for every command uses too much CPU. */
    #define LUA_GC_CYCLE_PERIOD 50
    {
        static long gc_count = 0;

        gc_count++;
        if (gc_count == LUA_GC_CYCLE_PERIOD) {
            lua_gc(lua,LUA_GCSTEP,LUA_GC_CYCLE_PERIOD);
            gc_count = 0;
        }
    }

    if (err) {
        addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
            funcname, lua_tostring(lua,-1));
        lua_pop(lua,2); /* Consume the Lua reply and remove error handler. */
    } else {
        /* On success convert the Lua return value into Redis protocol, and
         * send it to * the client. */
        luaReplyToRedisReply(c,lua); /* Convert and consume the reply. */
        lua_pop(lua,1); /* Remove the error handler. */
    }

    /* If we are using single commands replication, emit EXEC if there
     * was at least a write. */
    if (server.lua_replicate_commands) {
        preventCommandPropagation(c);
        if (server.lua_multi_emitted) {
            execCommandPropagateExec(c);
        }
    }

    /* EVALSHA should be propagated to Slave and AOF file as full EVAL, unless
     * we are sure that the script was already in the context of all the
     * attached slaves *and* the current AOF file if enabled.
     *
     * To do so we use a cache of SHA1s of scripts that we already propagated
     * as full EVAL, that's called the Replication Script Cache.
     *
     * For replication, everytime a new slave attaches to the master, we need to
     * flush our cache of scripts that can be replicated as EVALSHA, while
     * for AOF we need to do so every time we rewrite the AOF file. */
    if (evalsha && !server.lua_replicate_commands) {
        if (!replicationScriptCacheExists(c->argv[1]->ptr)) {
            /* This script is not in our script cache, replicate it as
             * EVAL, then add it into the script cache, as from now on
             * slaves and AOF know about it. */
            robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);

            replicationScriptCacheAdd(c->argv[1]->ptr);
            serverAssertWithInfo(c,NULL,script != NULL);

            /* If the script did not produce any changes in the dataset we want
             * just to replicate it as SCRIPT LOAD, otherwise we risk running
             * an aborted script on slaves (that may then produce results there)
             * or just running a CPU costly read-only script on the slaves. */
            if (server.dirty == initial_server_dirty) {
                rewriteClientCommandVector(c,3,
                    resetRefCount(createStringObject("SCRIPT",6)),
                    resetRefCount(createStringObject("LOAD",4)),
                    script);
            } else {
                rewriteClientCommandArgument(c,0,
                    resetRefCount(createStringObject("EVAL",4)));
                rewriteClientCommandArgument(c,1,script);
            }
            forceCommandPropagation(c,PROPAGATE_REPL|PROPAGATE_AOF);
        }
    }
}
void evalGenericCommand(client *c, int evalsha) {
    lua_State *lua = server.lua;
    char funcname[43];
    long long numkeys;
    long long initial_server_dirty = server.dirty;
    int delhook = 0, err;

     
    redisSrand48(0);

     
    server.lua_random_dirty = 0;
    server.lua_write_dirty = 0;
    server.lua_replicate_commands = server.lua_always_replicate_commands;
    server.lua_multi_emitted = 0;
    server.lua_repl = PROPAGATE_AOF|PROPAGATE_REPL;

     
    if (getLongLongFromObjectOrReply(c,c->argv[2],&numkeys,NULL) != C_OK)
        return;
    if (numkeys > (c->argc - 3)) {
        addReplyError(c,"Number of keys can't be greater than number of args");
        return;
    } else if (numkeys < 0) {
        addReplyError(c,"Number of keys can't be negative");
        return;
    }

     
    funcname[0] = 'f';
    funcname[1] = '_';
    if (!evalsha) {
         
        sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr));
    } else {
         
        int j;
        char *sha = c->argv[1]->ptr;

         
        for (j = 0; j < 40; j++)
            funcname[j+2] = (sha[j] >= 'A' && sha[j] <= 'Z') ?
                sha[j]+('a'-'A') : sha[j];
        funcname[42] = '\0';
    }

     
    lua_getglobal(lua, "__redis__err__handler");

     
    lua_getglobal(lua, funcname);
    if (lua_isnil(lua,-1)) {
        lua_pop(lua,1);  
         
        if (evalsha) {
            lua_pop(lua,1);  
            addReply(c, shared.noscripterr);
            return;
        }
        if (luaCreateFunction(c,lua,c->argv[1]) == NULL) {
            lua_pop(lua,1);  
             
            return;
        }
         
        lua_getglobal(lua, funcname);
        serverAssert(!lua_isnil(lua,-1));
    }

     
    luaSetGlobalArray(lua,"KEYS",c->argv+3,numkeys);
    luaSetGlobalArray(lua,"ARGV",c->argv+3+numkeys,c->argc-3-numkeys);

     
    server.lua_caller = c;
    server.lua_cur_script = funcname + 2;
    server.lua_time_start = mstime();
    server.lua_kill = 0;
    if (server.lua_time_limit > 0 && ldb.active == 0) {
        lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);
        delhook = 1;
    } else if (ldb.active) {
        lua_sethook(server.lua,luaLdbLineHook,LUA_MASKLINE|LUA_MASKCOUNT,100000);
        delhook = 1;
    }

    prepareLuaClient();

     
    err = lua_pcall(lua,0,1,-2);

    resetLuaClient();

     
    if (delhook) lua_sethook(lua,NULL,0,0);  
    if (server.lua_timedout) {
        server.lua_timedout = 0;
         
        unprotectClient(c);
        if (server.masterhost && server.master)
            queueClientForReprocessing(server.master);
    }
    server.lua_caller = NULL;
    server.lua_cur_script = NULL;

     
    #define LUA_GC_CYCLE_PERIOD 50
    {
        static long gc_count = 0;

        gc_count++;
        if (gc_count == LUA_GC_CYCLE_PERIOD) {
            lua_gc(lua,LUA_GCSTEP,LUA_GC_CYCLE_PERIOD);
            gc_count = 0;
        }
    }

    if (err) {
        addReplyErrorFormat(c,"Error running script (call to %s): %s\n",
            funcname, lua_tostring(lua,-1));
        lua_pop(lua,2);  
    } else {
         
        luaReplyToRedisReply(c,lua);  
        lua_pop(lua,1);  
    }

     
    if (server.lua_replicate_commands) {
        preventCommandPropagation(c);
        if (server.lua_multi_emitted) {
            execCommandPropagateExec(c);
        }
    }

     
    if (evalsha && !server.lua_replicate_commands) {
        if (!replicationScriptCacheExists(c->argv[1]->ptr)) {
             
            robj *script = dictFetchValue(server.lua_scripts,c->argv[1]->ptr);

            replicationScriptCacheAdd(c->argv[1]->ptr);
            serverAssertWithInfo(c,NULL,script != NULL);

             
            if (server.dirty == initial_server_dirty) {
                rewriteClientCommandVector(c,3,
                    resetRefCount(createStringObject("SCRIPT",6)),
                    resetRefCount(createStringObject("LOAD",4)),
                    script);
            } else {
                rewriteClientCommandArgument(c,0,
                    resetRefCount(createStringObject("EVAL",4)));
                rewriteClientCommandArgument(c,1,script);
            }
            forceCommandPropagation(c,PROPAGATE_REPL|PROPAGATE_AOF);
        }
    }
}