Fix some format strings and some return types.

[moritzbuhl]

No description provided.

[lxin]

including 'read(fd, req->data, req->len)', can you make the above into a loop? like:

off = req->data;
left = req->len;

while (left > 0) {
    ret = read(fd, off, left);
    if (ret < 0)
        goto err
    off += ret;
    left -= ret;
}

also try to move the variables definition at the beginning of the function in reversed Christmas tree order, like:

        struct http_request *req = user_data;
        char len[10], status[] = "200";
        nghttp3_data_reader dr = {};
        char path[128] = {};
        nghttp3_nv nva[4];
        struct stat st;
        uint8_t *off;
        int ret, fd;
        size_t left;

[lxin]

here, move 'sent' and 'n' down just to look better, :-)

        int ret, i, flags = 0, fin = 0;
        int64_t stream_id = -1;
        nghttp3_vec vec[16];
        nghttp3_ssize cnt;
        size_t sent;
        ssize_t n;