blob: 6a7175c3092f2b0f07c41b1a400f0b2351094ee7 [file] [log] [blame]
// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library fuchsia.update;
using zx;
/// A reporter for whether the currently booted system is committed. When an
/// update is committed, this means:
/// * The currently booted slot is marked as healthy (e.g. successfully booted).
/// * The alternate slot (if present) is marked as unbootable.
/// * The system will not roll back to the previous version of the OS on reboot.
/// * The previous version of the OS may be garbage collected.
/// Until the update is committed, the system retains the prior version of the OS.
/// That way, if we discover the newly written version is bad (e.g. it cannot itself
/// update), then the system can fall back to the previous committed version.
protocol CommitStatusProvider {
/// Determines whether the currently booted system is committed, and immediately
/// returns an EventPair.
/// * If the currently booted system is committed, the `ZX_USER_SIGNAL_0` signal
/// is asserted on the EventPair, e.g. the signal is asserted before the
/// EventPair is returned.
/// * If the commit is pending, no signals are asserted on the EventPair. When the
/// system is committed, `ZX_USER_SIGNAL_0` is asserted on the EventPair.
/// * If the system fails to commit the currently booted version, the system
/// will reboot and terminate the component serving [`CommitStatusProvider`],
/// which will assert `ZX_EVENTPAIR_PEER_CLOSED`. At this point, any remaining
/// EventPairs will observe the `ZX_EVENTPAIR_PEER_CLOSED` signal.
/// - response `event` an EventPair with rights `ZX_RIGHTS_BASIC`.
IsCurrentSystemCommitted() -> (zx.handle:EVENTPAIR event);