Re: [Qemu-devel] [PATCH 02/18] Introduce read() to FdMigrationState.

[Anthony Liguori <anthony@codemonkey.ws>]

On 02/10/2011 10:30 AM, Yoshiaki Tamura wrote:
> Currently FdMigrationState doesn't support read(), and this patch
> introduces it to get response from the other side.
>
> Signed-off-by: Yoshiaki Tamura<tamura.yoshiaki@lab.ntt.co.jp>
>    

Migration is unidirectional.  Changing this is fundamental and not 
something to be done lightly.

I thought we previously discussed using a protocol wrapper around the 
existing migration protocol?

Regards,

Anthony Liguori

> ---
>   migration-tcp.c |   15 +++++++++++++++
>   migration.c     |   13 +++++++++++++
>   migration.h     |    3 +++
>   3 files changed, 31 insertions(+), 0 deletions(-)
>
> diff --git a/migration-tcp.c b/migration-tcp.c
> index b55f419..55777c8 100644
> --- a/migration-tcp.c
> +++ b/migration-tcp.c
> @@ -39,6 +39,20 @@ static int socket_write(FdMigrationState *s, const void * buf, size_t size)
>       return send(s->fd, buf, size, 0);
>   }
>
> +static int socket_read(FdMigrationState *s, const void * buf, size_t size)
> +{
> +    ssize_t len;
> +
> +    do {
> +        len = recv(s->fd, (void *)buf, size, 0);
> +    } while (len == -1&&  socket_error() == EINTR);
> +    if (len == -1) {
> +        len = -socket_error();
> +    }
> +
> +    return len;
> +}
> +
>   static int tcp_close(FdMigrationState *s)
>   {
>       DPRINTF("tcp_close\n");
> @@ -94,6 +108,7 @@ MigrationState *tcp_start_outgoing_migration(Monitor *mon,
>
>       s->get_error = socket_errno;
>       s->write = socket_write;
> +    s->read = socket_read;
>       s->close = tcp_close;
>       s->mig_state.cancel = migrate_fd_cancel;
>       s->mig_state.get_status = migrate_fd_get_status;
> diff --git a/migration.c b/migration.c
> index 3612572..f0df5fc 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -340,6 +340,19 @@ ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
>       return ret;
>   }
>
> +int migrate_fd_get_buffer(void *opaque, uint8_t *data, int64_t pos, size_t size)
> +{
> +    FdMigrationState *s = opaque;
> +    int ret;
> +
> +    ret = s->read(s, data, size);
> +    if (ret == -1) {
> +        ret = -(s->get_error(s));
> +    }
> +
> +    return ret;
> +}
> +
>   void migrate_fd_connect(FdMigrationState *s)
>   {
>       int ret;
> diff --git a/migration.h b/migration.h
> index 2170792..88a6987 100644
> --- a/migration.h
> +++ b/migration.h
> @@ -48,6 +48,7 @@ struct FdMigrationState
>       int (*get_error)(struct FdMigrationState*);
>       int (*close)(struct FdMigrationState*);
>       int (*write)(struct FdMigrationState*, const void *, size_t);
> +    int (*read)(struct FdMigrationState *, const void *, size_t);
>       void *opaque;
>   };
>
> @@ -116,6 +117,8 @@ void migrate_fd_put_notify(void *opaque);
>
>   ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size);
>
> +int migrate_fd_get_buffer(void *opaque, uint8_t *data, int64_t pos, size_t size);
> +
>   void migrate_fd_connect(FdMigrationState *s);
>
>   void migrate_fd_put_ready(void *opaque);
>