Function sendSync

src/redis-cli.c:6182–6217

Sends SYNC and reads the number of bytes in the payload. Used both by * slaveMode() and getRDB(). * returns 0 in case an EOF marker is used. */

 * slaveMode() and getRDB().
 * returns 0 in case an EOF marker is used. */
unsigned long long sendSync(redisContext *c, char *out_eof) {
    /* To start we need to send the SYNC command and return the payload.
     * The hiredis client lib does not understand this part of the protocol
     * and we don't want to mess with its buffers, so everything is performed
     * using direct low-level I/O. */
    char buf[4096], *p;
    ssize_t nread;

    /* Send the SYNC command. */
    if (cliWriteConn(c, "SYNC\r\n", 6) != 6) {
        fprintf(stderr,"Error writing to master\n");
        exit(1);
    }

    /* Read $<payload>\r\n, making sure to read just up to "\n" */
    p = buf;
    while(1) {
        nread = readConn(c,p,1);
        if (nread <= 0) {
            fprintf(stderr,"Error reading bulk length while SYNCing\n");
            exit(1);
        }
        if (*p == '\n' && p != buf) break;
        if (*p != '\n') p++;
    }
    *p = '\0';
    if (buf[0] == '-') {
        fprintf(stderr, "SYNC with master failed: %s\n", buf);
        exit(1);
    }
    if (strncmp(buf+1,"EOF:",4) == 0 && strlen(buf+5) >= RDB_EOF_MARK_SIZE) {
        memcpy(out_eof, buf+5, RDB_EOF_MARK_SIZE);
        return 0;
    }
    return strtoull(buf+1,NULL,10);
}

static void slaveMode(void) {
    static char eofmark[RDB_EOF_MARK_SIZE];