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Commit 1bbf8f04 authored by Akilesh Kailash's avatar Akilesh Kailash
Browse files

libsnapshot: Check if the vendor is updated from Android S for GRF 



In a GRF config, if Vendor partition is updated from Android 12; post
OTA reboot, first stage init will communicate to daemon to check if the
daemon can support socket handoff. If that succeeds, then it is a signal
that the vendor has been updated from Android 12. Use a marker in
/metadata to signal that the vendor was updated. If the marker is present,
then post OTA reboot, userspace snapshot will be used.

Bug: 333854394
Test: OTA
Android U (system) + S (vendor) -> Android V (system) + V (Vendor)

Change-Id: Ie38c4379010789a84e5b44529b407f9f82135271
Signed-off-by: default avatarAkilesh Kailash <akailash@google.com>
parent 116a7133

fs_mgr/libsnapshot/include/libsnapshot/snapshot.h

+4 −0
Original line number Diff line number Diff line
@@ -335,6 +335,9 @@ class SnapshotManager final : public ISnapshotManager { 
    // after loading selinux policy.

    bool PrepareSnapuserdArgsForSelinux(std::vector<std::string>* snapuserd_argv);



    // If snapuserd from first stage init was started from system partition.

    bool MarkSnapuserdFromSystem();



    // Detach dm-user devices from the first stage snapuserd. Load

    // new dm-user tables after loading selinux policy.

    bool DetachFirstStageSnapuserdForSelinux();
@@ -670,6 +673,7 @@ class SnapshotManager final : public ISnapshotManager { 
    std::string GetForwardMergeIndicatorPath();

    std::string GetOldPartitionMetadataPath();

    std::string GetBootSnapshotsWithoutSlotSwitchPath();

    std::string GetSnapuserdFromSystemPath();



    const LpMetadata* ReadOldPartitionMetadata(LockedFile* lock);

fs_mgr/libsnapshot/snapshot.cpp

+31 −1
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ static constexpr char kBootSnapshotsWithoutSlotSwitch[] = 
        "/metadata/ota/snapshot-boot-without-slot-switch";

static constexpr char kBootIndicatorPath[] = "/metadata/ota/snapshot-boot";

static constexpr char kRollbackIndicatorPath[] = "/metadata/ota/rollback-indicator";

static constexpr char kSnapuserdFromSystem[] = "/metadata/ota/snapuserd-from-system";

static constexpr auto kUpdateStateCheckInterval = 2s;

/*

 * The readahead size is set to 32kb so that
@@ -318,7 +319,7 @@ bool SnapshotManager::RemoveAllUpdateState(LockedFile* lock, const std::function 
    std::vector<std::string> files = {

            GetSnapshotBootIndicatorPath(),          GetRollbackIndicatorPath(),

            GetForwardMergeIndicatorPath(),          GetOldPartitionMetadataPath(),

            GetBootSnapshotsWithoutSlotSwitchPath(),

            GetBootSnapshotsWithoutSlotSwitchPath(), GetSnapuserdFromSystemPath(),

    };

    for (const auto& file : files) {

        RemoveFileIfExists(file);
@@ -1457,6 +1458,10 @@ std::string SnapshotManager::GetRollbackIndicatorPath() { 
    return metadata_dir_ + "/" + android::base::Basename(kRollbackIndicatorPath);

}



std::string SnapshotManager::GetSnapuserdFromSystemPath() {

    return metadata_dir_ + "/" + android::base::Basename(kSnapuserdFromSystem);

}



std::string SnapshotManager::GetForwardMergeIndicatorPath() {

    return metadata_dir_ + "/allow-forward-merge";

}
@@ -2122,6 +2127,16 @@ bool SnapshotManager::UpdateUsesODirect(LockedFile* lock) { 
    return update_status.o_direct();

}



bool SnapshotManager::MarkSnapuserdFromSystem() {

    auto path = GetSnapuserdFromSystemPath();



    if (!android::base::WriteStringToFile("1", path)) {

        PLOG(ERROR) << "Unable to write to vendor update path: " << path;

        return false;

    }

    return true;

}



/*

 * Please see b/304829384 for more details.

 *
@@ -2158,11 +2173,26 @@ bool SnapshotManager::UpdateUsesODirect(LockedFile* lock) { 
 *         iii: If both (i) and (ii) are true, then use the dm-snapshot based

 *         approach.

 *

 * 3: Post OTA reboot, if the vendor partition was updated from Android 12 to

 * any other release post Android 12, then snapuserd binary will be "system"

 * partition as post Android 12, init_boot will contain a copy of snapuserd

 * binary. Thus, during first stage init, if init is able to communicate to

 * daemon, that gives us a signal that the binary is from "system" copy. Hence,

 * there is no need to fallback to legacy dm-snapshot. Thus, init will use a

 * marker in /metadata to signal that the snapuserd binary from first stage init

 * can handle userspace snapshots.

 *

 */

bool SnapshotManager::IsLegacySnapuserdPostReboot() {

    if (is_legacy_snapuserd_.has_value() && is_legacy_snapuserd_.value() == true) {

        auto slot = GetCurrentSlot();

        if (slot == Slot::Target) {

            // If this marker is present, then daemon can handle userspace

            // snapshots; also, it indicates that the vendor partition was

            // updated from Android 12.

            if (access(GetSnapuserdFromSystemPath().c_str(), F_OK) == 0) {

                return false;

            }

            return true;

        }

    }

init/first_stage_mount.cpp

+1 −6
Original line number Diff line number Diff line
@@ -395,12 +395,7 @@ bool FirstStageMountVBootV2::CreateSnapshotPartitions(SnapshotManager* sm) { 


    use_snapuserd_ = sm->IsSnapuserdRequired();

    if (use_snapuserd_) {

        if (sm->UpdateUsesUserSnapshots()) {

        LaunchFirstStageSnapuserd();

        } else {

            LOG(FATAL) << "legacy virtual-ab is no longer supported";

            return false;

        }

    }



    sm->SetUeventRegenCallback([this](const std::string& device) -> bool {

init/snapuserd_transition.cpp

+4 −0
Original line number Diff line number Diff line
@@ -100,6 +100,10 @@ void LaunchFirstStageSnapuserd() { 
    }

    if (client->SupportsSecondStageSocketHandoff()) {

        setenv(kSnapuserdFirstStageInfoVar, "socket", 1);

        auto sm = SnapshotManager::NewForFirstStageMount();

        if (!sm->MarkSnapuserdFromSystem()) {

            LOG(ERROR) << "Failed to update MarkSnapuserdFromSystem";

        }

    }



    setenv(kSnapuserdFirstStagePidVar, std::to_string(pid).c_str(), 1);