Re: [Qemu-devel] [PATCH 5/5] qmp: add DEVICE_TRAY_MOVED event

[Markus Armbruster]

Luiz Capitulino <address@hidden> writes:

> It's emitted whenever the tray is moved by the guest or by HMP/QMP
> commands.
>
> Signed-off-by: Luiz Capitulino <address@hidden>
> ---
>  QMP/qmp-events.txt |   18 ++++++++++++++++++
>  block.c            |   24 ++++++++++++++++++++++++
>  monitor.c          |    3 +++
>  monitor.h          |    1 +
>  4 files changed, 46 insertions(+), 0 deletions(-)
>
> diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
> index 06cb404..9286af5 100644
> --- a/QMP/qmp-events.txt
> +++ b/QMP/qmp-events.txt
> @@ -26,6 +26,24 @@ Example:
>  Note: If action is "stop", a STOP event will eventually follow the
>  BLOCK_IO_ERROR event.
>  
> +DEVICE_TRAY_MOVED
> +-----------------
> +
> +It's emitted whenever the tray of a removable device is moved by the guest
> +or by HMP/QMP commands.
> +
> +Data:
> +
> +- "device": device name (json-string)
> +- "tray-open": true if the tray has been opened or false if it has been 
> closed
> +               (json-bool)
> +
> +{ "event": "DEVICE_TRAY_MOVED",
> +  "data": { "device": "ide1-cd0",
> +            "tray-open": true
> +  },
> +  "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }
> +
>  RESET
>  -----
>  
> diff --git a/block.c b/block.c
> index bfb0dec..e27d528 100644
> --- a/block.c
> +++ b/block.c
> @@ -972,10 +972,30 @@ void bdrv_emit_qmp_error_event(const BlockDriverState 
> *bdrv,
>      qobject_decref(data);
>  }
>  
> +static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected)
> +{
> +    QObject *data;
> +
> +    data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }",
> +                              bdrv_get_device_name(bs), ejected);
> +    monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data);
> +
> +    qobject_decref(data);
> +}
> +
>  static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
>  {
>      if (bs->dev_ops && bs->dev_ops->change_media_cb) {
> +        bool tray_was_closed = !bdrv_dev_is_tray_open(bs);
>          bs->dev_ops->change_media_cb(bs->dev_opaque, load);
> +        if (tray_was_closed) {
> +            /* tray open */
> +            bdrv_emit_qmp_eject_event(bs, true);
> +        }
> +        if (load) {
> +            /* tray close */
> +            bdrv_emit_qmp_eject_event(bs, false);
> +        }
>      }
>  }
>  

This one's subtle.  I discussed why it works in my review of v2, but
I'll be hanged if I remember now.  I'd ask for a comment, if I hadn't
already asked for replacing the BlockDevOps method by one that's easier
to use, in a followup patch.

> @@ -3616,6 +3636,10 @@ void bdrv_eject(BlockDriverState *bs, bool eject_flag)
>      if (drv && drv->bdrv_eject) {
>          drv->bdrv_eject(bs, eject_flag);
>      }
> +
> +    if (bs->device_name[0] != '\0') {
> +        bdrv_emit_qmp_eject_event(bs, eject_flag);
> +    }

Condition needed when we stack "raw" on top of another driver.
raw_eject() uses bdrv_eject() to pass down the call.

Only the topmost driver ("raw" in this case) has a non-empty
device_name.

Perhaps worth a comment.

>  }
>  
>  /**
> diff --git a/monitor.c b/monitor.c
> index aadbdcb..38d876e 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -485,6 +485,9 @@ void monitor_protocol_event(MonitorEvent event, QObject 
> *data)
>          case QEVENT_BLOCK_JOB_CANCELLED:
>              event_name = "BLOCK_JOB_CANCELLED";
>              break;
> +        case QEVENT_DEVICE_TRAY_MOVED:
> +             event_name = "DEVICE_TRAY_MOVED";
> +            break;
>          default:
>              abort();
>              break;
> diff --git a/monitor.h b/monitor.h
> index b72ea07..b6f700f 100644
> --- a/monitor.h
> +++ b/monitor.h
> @@ -38,6 +38,7 @@ typedef enum MonitorEvent {
>      QEVENT_SPICE_DISCONNECTED,
>      QEVENT_BLOCK_JOB_COMPLETED,
>      QEVENT_BLOCK_JOB_CANCELLED,
> +    QEVENT_DEVICE_TRAY_MOVED,
>      QEVENT_MAX,
>  } MonitorEvent;