Re: [PATCH v4 2/2] migration: check magic value for deciding the mapping of channels

[Peter Xu]

On Wed, Nov 23, 2022 at 03:05:27PM +0000, manish.mishra wrote:
> +int migration_channel_read_peek(QIOChannel *ioc,
> +                                const char *buf,
> +                                const size_t buflen,
> +                                Error **errp)
> +{
> +   ssize_t len = 0;
> +   struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
> +
> +   while (len < buflen) {
> +       len = qio_channel_readv_full(ioc, &iov, 1, NULL,
> +                                    NULL, QIO_CHANNEL_READ_FLAG_MSG_PEEK, 
> errp);
> +
> +       if (len == QIO_CHANNEL_ERR_BLOCK) {

This needs to take care of partial len too?

> +            if (qemu_in_coroutine()) {
> +                /* 1ms sleep. */
> +                qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000);
> +            } else {
> +                qio_channel_wait(ioc, G_IO_IN);
> +            }
> +            continue;
> +       }
> +       if (len == 0) {
> +           error_setg(errp,
> +                      "Unexpected end-of-file on channel");
> +           return -1;
> +       }
> +       if (len < 0) {
> +           return -1;
> +       }
> +   }
> +
> +   return 0;
> +}

-- 
Peter Xu