class WireSyncClientImpl

Requests that the driver format the underlying block device as described

by the parameters in `config`, and enter `authoring` mode.

If `config` has any unpopulated fields, or those fields contain enum

values that are not known to this version of the driver, this method

will return `ZX_ERR_INVALID_ARGS`.

If the device was not in `closed` mode at the time of the call, this

method will return `ZX_ERR_BAD_STATE`.

If the underlying block device returns an error, this method will return

that same error code.

On success, the driver will enter `authoring` mode, expose a child

device named `mutable` which speaks the `fuchsia.hardware.block`

protocol in the device tree, then return.

Allocates 80 bytes of message buffer on the stack. No heap allocation necessary.

Requests that the device in `authoring` mode:

* unbind the child device named `mutable`

* regenerate the integrity data necessary to provide the guarantees

expected by `OpenForVerifiedRead`

* flush all writes to the underlying block device

* switch to `closed` mode

* return a `Seal` that can be used to ensure that any data read in the

future from this device matches that which was written prior to this

particular call of `CloseAndGenerateSeal`.

If the device was not in "authoring" mode at the time of the call, this

function will return `ZX_ERR_BAD_STATE` and have no visible side effects.

If the underlying block device returns a failure while regenerating

integrity data or flushing writes, the device will enter the `failed` mode

and this call will propagate that error.

On success, the returned `seal` will contain a hash of the device

superblock that should be stored in tamper-proof storage, so it can be

retrieved and presented in a future `OpenForVerifiedRead` call.

Allocates 96 bytes of message buffer on the stack. No heap allocation necessary.

Requests that the device verify that the provided `config` matches the

one on disk, and that the given `seal` covers the content of the

superblock. If all match as expected, then the device will bind a child

device named `verified` which speaks the `fuchsia.hardware.block`

protocol and enter the `verified-read` mode. Reads issued to the

`verified` block device will either successfully return the same content

as the `mutable` block device would have returned at the time the volume

was authored, or return a failure. That is to say: modifying the

underlying storage will cause the `verified` device to return read

failures for any modified blocks as `ZX_ERR_IO_DATA_INTEGRITY` rather

than data other than what was present at the time `CloseAndGenerateSeal`

was called.

* Returns `ZX_ERR_BAD_STATE` if the device was not in the `closed`

state at the time of the call

* Returns `ZX_ERR_INVALID_ARGS` if `config` lacks either `hash_function` or `block_size`

* Returns `ZX_ERR_INVALID_ARGS` if `seal` is of an unrecognized variant

* Returns `ZX_ERR_IO_DATA_INTEGRITY` if the `seal` provided is inconsistent with

the superblock, or if the properties in `config` are inconsistent with the

configuration data stored in the superblock on the underlying block device.

* Returns the underlying I/O error code if the underlying block device

returns an error.

On success, the device binds a child device `verified`, enters

`verified-read` mode, and returns from this call.

Allocates 128 bytes of message buffer on the stack. No heap allocation necessary.

Requests that the device in either `authoring` mode or `verified-read` mode

unbind any child devices and return to `closed` mode.

Returns `ZX_ERR_BAD_STATE` if the device is not in `authoring` or

`verified-read` mode at the time of the call.

On success, the device does the following:

* If the device was in `authoring` mode, removes the child `mutable` device

* If the device was in `verified-read` mode, removes the child `verified` device

* Enters `closed` mode.

* Returns from this call

Allocates 48 bytes of message buffer on the stack. No heap allocation necessary.