Re: [Qemu-devel] [PATCH 25/25] hmp: add NBD server commands

[Markus Armbruster]

Paolo Bonzini <address@hidden> writes:

> Acked-by: Luiz Capitulino <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  hmp-commands.hx | 29 +++++++++++++++++++++++++++++
>  hmp.c           | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  hmp.h           |  2 ++
>  3 file modificati, 86 inserzioni(+)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index e0b537d..f5d9204 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1274,6 +1274,35 @@ Remove all matches from the access control list, and 
> set the default
>  policy back to @code{deny}.
>  ETEXI
>  
> +    {
> +        .name       = "nbd_server_start",
> +        .args_type  = "writable:-w,uri:s",
> +        .params     = "nbd_server_start [-w] host:port",
> +        .help       = "serve block devices on the given host and port",
> +        .mhandler.cmd = hmp_nbd_server_start,
> +    },
> +STEXI
> address@hidden nbd_server_start @var{host}:@var{port}
> address@hidden nbd_server_start
> +Start an NBD server on the given host and/or port, and serve all of the
> +virtual machine's block devices that have an inserted media on it.
> +The @option{-w} option makes the devices writable.
> +ETEXI
> +
> +    {
> +        .name       = "nbd_server_stop",
> +        .args_type  = "",
> +        .params     = "nbd_server_stop",
> +        .help       = "stop serving block devices using the NBD protocol",
> +        .mhandler.cmd = hmp_nbd_server_stop,
> +    },
> +STEXI
> address@hidden nbd_server_stop
> address@hidden nbd_server_stop
> +Stop the QEMU embedded NBD server.
> +ETEXI
> +
> +

Why's nbd_server_add not needed in HMP?

Oh, it's because HMP's nbd_server_start auto-adds *all* block devices,
unlinke QMP's nbd-server-start.

Are you sure that's a good idea?

>  #if defined(TARGET_I386)
>  
>      {
> diff --git a/hmp.c b/hmp.c
> index 70bdec2..edf6397 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -18,6 +18,7 @@
>  #include "qemu-option.h"
>  #include "qemu-timer.h"
>  #include "qmp-commands.h"
> +#include "qemu_socket.h"
>  #include "monitor.h"
>  #include "console.h"
>  
> @@ -1209,3 +1210,57 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
>      qmp_screendump(filename, &err);
>      hmp_handle_error(mon, &err);
>  }
> +
> +void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
> +{
> +    const char *uri = qdict_get_str(qdict, "uri");
> +    int writable = qdict_get_try_bool(qdict, "writable", 0);
> +    Error *local_err = NULL;
> +    BlockInfoList *block_list, *info;
> +    SocketAddress *addr;
> +
> +    /* First check if the address is valid and start the server.  */
> +    addr = socket_parse(uri, &local_err);
> +    if (local_err != NULL) {
> +        goto exit;
> +    }
> +
> +    qmp_nbd_server_start(addr, &local_err);
> +    qapi_free_SocketAddress(addr);
> +    if (local_err != NULL) {
> +        goto exit;
> +    }
> +
> +    /* Then try adding all block devices.  If one fails, close all and
> +     * exit.
> +     */
> +    block_list = qmp_query_block(NULL);
> +
> +    for (info = block_list; info; info = info->next) {
> +        if (!info->value->has_inserted) {
> +            continue;
> +        }
> +
> +        qmp_nbd_server_add(info->value->device,
> +                           true, !info->value->inserted->ro && writable,
> +                           &local_err);
> +
> +        if (local_err != NULL) {
> +            qmp_nbd_server_stop(NULL);
> +            break;
> +        }
> +    }

Here's where it auto-adds block devices.

> +
> +    qapi_free_BlockInfoList(block_list);
> +
> +exit:
> +    hmp_handle_error(mon, &local_err);
> +}
> +
> +void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict)
> +{
> +    Error *errp = NULL;
> +
> +    qmp_nbd_server_stop(&errp);
> +    hmp_handle_error(mon, &errp);
> +}
> diff --git a/hmp.h b/hmp.h
> index 71ea384..45b7c48 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -75,5 +75,7 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
>  void hmp_closefd(Monitor *mon, const QDict *qdict);
>  void hmp_send_key(Monitor *mon, const QDict *qdict);
>  void hmp_screen_dump(Monitor *mon, const QDict *qdict);
> +void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
> +void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
>  
>  #endif