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Re: [Qemu-devel] [PATCH 11/27] hmp: hmp_cont(): don't rely on QERR_DEVIC
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH 11/27] hmp: hmp_cont(): don't rely on QERR_DEVICE_ENCRYPTED |
Date: |
Wed, 01 Aug 2012 13:37:44 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) |
Luiz Capitulino <address@hidden> writes:
> Today, hmp_cont() checks for QERR_DEVICE_ENCRYPTED in order to know
> if qmp_cont() failed due to an encrypted device. If it did,
> hmp_cont() accesses QERR_DEVICE_ENCRYPTED's data member 'device' to
> precisely know for which device an encryption key must be set.
>
> However, all errors data members are going to be dropped by a later
> commit, so hmp_cont() can't do this anymore.
>
> This commit changes hmp_cont() to loop through all block devices
> and proactively set an encryption key for any encrypted device
> without a valid one.
>
> Signed-off-by: Luiz Capitulino <address@hidden>
> ---
> hmp.c | 43 +++++++++++++++++++++++++------------------
> 1 file changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/hmp.c b/hmp.c
> index 6b72a64..a906f8a 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -610,34 +610,41 @@ void hmp_pmemsave(Monitor *mon, const QDict *qdict)
>
> static void hmp_cont_cb(void *opaque, int err)
> {
> - Monitor *mon = opaque;
> -
> if (!err) {
> - hmp_cont(mon, NULL);
> + qmp_cont(NULL);
> }
> }
>
> -void hmp_cont(Monitor *mon, const QDict *qdict)
> +static bool block_dev_is_encrypted(const BlockInfo *bdev)
> {
> - Error *errp = NULL;
> -
> - qmp_cont(&errp);
> - if (error_is_set(&errp)) {
> - if (error_is_type(errp, QERR_DEVICE_ENCRYPTED)) {
> - const char *device;
> + return (bdev->inserted && bdev->inserted->encrypted);
> +}
>
> - /* The device is encrypted. Ask the user for the password
> - and retry */
> +static bool block_dev_key_is_set(const BlockInfo *bdev)
> +{
> + return (bdev->inserted && bdev->inserted->valid_encryption_key);
> +}
New static helpers block_dev_is_encrypted(), block_dev_key_is_set().
They work on BlockInfo. Call them blockinfo_{is_encrypted,key_is_set}()?
>
> - device = error_get_field(errp, "device");
> - assert(device != NULL);
> +void hmp_cont(Monitor *mon, const QDict *qdict)
> +{
> + BlockInfoList *bdev_list, *bdev;
> + Error *errp = NULL;
>
> - monitor_read_block_device_key(mon, device, hmp_cont_cb, mon);
> - error_free(errp);
> - return;
> + bdev_list = qmp_query_block(NULL);
> + for (bdev = bdev_list; bdev; bdev = bdev->next) {
> + if (block_dev_is_encrypted(bdev->value) &&
> + !block_dev_key_is_set(bdev->value)) {
> + monitor_read_block_device_key(mon, bdev->value->device,
> + hmp_cont_cb, NULL);
> + goto out;
Any particular reason for creating BlockInfos just to find out whether
we lack the key? Why not bdrv_key_required()?
> }
> - hmp_handle_error(mon, &errp);
> }
> +
> + qmp_cont(&errp);
> + hmp_handle_error(mon, &errp);
> +
> +out:
> + qapi_free_BlockInfoList(bdev_list);
> }
>
> void hmp_system_wakeup(Monitor *mon, const QDict *qdict)
Diff makes this change look worse than it is. Odd: M-x ediff gets it
right. Anyway, here's how I think it works:
Unchanged qmp_cont(): search the bdrv_states for the first encrypted one
without a key. If found, set err argument to QERR_DEVICE_ENCRYPTED.
Other errors unrelated to encrypted devices are also possible.
hmp_cont() before: try qmp_cont(). If we get QERR_DEVICE_ENCRYPTED,
extract the device from the error object, and prompt for its key, with a
callback that retries hmp_cont() if the key was provided.
After: search the bdrv_states for an encrypted one without a key. If
there is none, qmp_cont(), no special error handling. If there is one,
prompt for its key, with a callback that runs qmp_cont() if the key was
provided.
Have you tested this with multiple devices lacking their key?
- Re: [Qemu-devel] [PATCH 11/27] hmp: hmp_cont(): don't rely on QERR_DEVICE_ENCRYPTED,
Markus Armbruster <=