Function helloCommand

app/redis-6.2.6/src/networking.c:2976–3049

HELLO [ [AUTH ] [SETNAME ] ] */

/* HELLO [<protocol-version> [AUTH <user> <password>] [SETNAME <name>] ] */
void helloCommand(client *c) {
    long long ver = 0;
    int next_arg = 1;

    if (c->argc >= 2) {
        if (getLongLongFromObjectOrReply(c, c->argv[next_arg++], &ver,
            "Protocol version is not an integer or out of range") != C_OK) {
            return;
        }

        if (ver < 2 || ver > 3) {
            addReplyError(c,"-NOPROTO unsupported protocol version");
            return;
        }
    }

    for (int j = next_arg; j < c->argc; j++) {
        int moreargs = (c->argc-1) - j;
        const char *opt = c->argv[j]->ptr;
        if (!strcasecmp(opt,"AUTH") && moreargs >= 2) {
            redactClientCommandArgument(c, j+1);
            redactClientCommandArgument(c, j+2);
            if (ACLAuthenticateUser(c, c->argv[j+1], c->argv[j+2]) == C_ERR) {
                addReplyError(c,"-WRONGPASS invalid username-password pair or user is disabled.");
                return;
            }
            j += 2;
        } else if (!strcasecmp(opt,"SETNAME") && moreargs) {
            if (clientSetNameOrReply(c, c->argv[j+1]) == C_ERR) return;
            j++;
        } else {
            addReplyErrorFormat(c,"Syntax error in HELLO option '%s'",opt);
            return;
        }
    }

    /* At this point we need to be authenticated to continue. */
    if (!c->authenticated) {
        addReplyError(c,"-NOAUTH HELLO must be called with the client already "
                        "authenticated, otherwise the HELLO AUTH <user> <pass> "
                        "option can be used to authenticate the client and "
                        "select the RESP protocol version at the same time");
        return;
    }

    /* Let's switch to the specified RESP mode. */
    if (ver) c->resp = ver;
    addReplyMapLen(c,6 + !server.sentinel_mode);

    addReplyBulkCString(c,"server");
    addReplyBulkCString(c,"redis");

    addReplyBulkCString(c,"version");
    addReplyBulkCString(c,REDIS_VERSION);

    addReplyBulkCString(c,"proto");
    addReplyLongLong(c,c->resp);