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Commit d2a02475 authored by Yifan Hong's avatar Yifan Hong
Browse files

libsnapshot: Add EnsureMetadataMounted 

In recovery, client is responsible for calling
EnsureMetadataMounted before doing (almost) all
operations on SnapshotManager, e.g.

- CancelUpdate() before sideloading
- BeginUpdate() on retrofit Virtual A/B before sideloading
- Finishing merge before flashing

Test: libsnapshot_test
Test: recovery sideload
Bug: 140749209
Change-Id: I1034a7fa74e31b6850896e61e86341239dbf2699
parent 82f1cbea

fs_mgr/libsnapshot/include/libsnapshot/auto_device.h

0 → 100644
+40 −0
Original line number Diff line number Diff line 
// Copyright (C) 2019 The Android Open Source Project

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//      http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.



#pragma once



#include <string>



#include <android-base/macros.h>



namespace android {

namespace snapshot {



// An abstract "device" that will be cleaned up (unmapped, unmounted, etc.) upon

// destruction.

struct AutoDevice {

    virtual ~AutoDevice(){};

    void Release();



  protected:

    AutoDevice(const std::string& name) : name_(name) {}

    std::string name_;



  private:

    DISALLOW_COPY_AND_ASSIGN(AutoDevice);

    AutoDevice(AutoDevice&& other) = delete;

};



}  // namespace snapshot

}  // namespace android

fs_mgr/libsnapshot/include/libsnapshot/snapshot.h

+19 −0
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ 
#include <liblp/liblp.h>

#include <update_engine/update_metadata.pb.h>



#include <libsnapshot/auto_device.h>



#ifndef FRIEND_TEST

#define FRIEND_TEST(test_set_name, individual_test) \

    friend class test_set_name##_##individual_test##_Test
@@ -120,6 +122,7 @@ class SnapshotManager final { 
        virtual const IPartitionOpener& GetPartitionOpener() const = 0;

        virtual bool IsOverlayfsSetup() const = 0;

        virtual bool SetBootControlMergeStatus(MergeStatus status) = 0;

        virtual bool IsRecovery() const = 0;

    };



    ~SnapshotManager();
@@ -209,6 +212,22 @@ class SnapshotManager final { 
    // Dump debug information.

    bool Dump(std::ostream& os);



    // Ensure metadata directory is mounted in recovery. When the returned

    // AutoDevice is destroyed, the metadata directory is automatically

    // unmounted.

    // Return nullptr if any failure.

    // In Android mode, Return an AutoDevice that does nothing

    // In recovery, return an AutoDevice that does nothing if metadata entry

    // is not found in fstab.

    // Note: if this function is called the second time before the AutoDevice returned from the

    // first call is destroyed, the device will be unmounted when any of these AutoDevices is

    // destroyed. FOr example:

    //   auto a = mgr->EnsureMetadataMounted(); // mounts

    //   auto b = mgr->EnsureMetadataMounted(); // does nothing

    //   b.reset() // unmounts

    //   a.reset() // does nothing

    std::unique_ptr<AutoDevice> EnsureMetadataMounted();



  private:

    FRIEND_TEST(SnapshotTest, CleanFirstStageMount);

    FRIEND_TEST(SnapshotTest, CreateSnapshot);

fs_mgr/libsnapshot/snapshot.cpp

+16 −0
Original line number Diff line number Diff line
@@ -77,6 +77,12 @@ using namespace std::string_literals; 


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



#ifdef __ANDROID_RECOVERY__

constexpr bool kIsRecovery = true;

#else

constexpr bool kIsRecovery = false;

#endif



class DeviceInfo final : public SnapshotManager::IDeviceInfo {

  public:

    std::string GetGsidDir() const override { return "ota"s; }
@@ -89,6 +95,7 @@ class DeviceInfo final : public SnapshotManager::IDeviceInfo { 
    }

    bool IsOverlayfsSetup() const override { return fs_mgr_overlayfs_is_setup(); }

    bool SetBootControlMergeStatus(MergeStatus status) override;

    bool IsRecovery() const override { return kIsRecovery; }



  private:

    android::fs_mgr::PartitionOpener opener_;
@@ -2065,5 +2072,14 @@ bool SnapshotManager::Dump(std::ostream& os) { 
    return ok;

}



std::unique_ptr<AutoDevice> SnapshotManager::EnsureMetadataMounted() {

    if (!device_->IsRecovery()) {

        // No need to mount anything in recovery.

        LOG(INFO) << "EnsureMetadataMounted does nothing in Android mode.";

        return std::unique_ptr<AutoUnmountDevice>(new AutoUnmountDevice());

    }

    return AutoUnmountDevice::New(device_->GetMetadataDir());

}



}  // namespace snapshot

}  // namespace android

fs_mgr/libsnapshot/snapshot_test.cpp

+63 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <android-base/properties.h>

#include <android-base/strings.h>

#include <android-base/unique_fd.h>

#include <fs_mgr/roots.h>

#include <fs_mgr_dm_linear.h>

#include <gtest/gtest.h>

#include <libdm/dm.h>
@@ -47,7 +48,10 @@ using android::fiemap::IImageManager; 
using android::fs_mgr::BlockDeviceInfo;

using android::fs_mgr::CreateLogicalPartitionParams;

using android::fs_mgr::DestroyLogicalPartition;

using android::fs_mgr::EnsurePathMounted;

using android::fs_mgr::EnsurePathUnmounted;

using android::fs_mgr::Extent;

using android::fs_mgr::Fstab;

using android::fs_mgr::GetPartitionGroupName;

using android::fs_mgr::GetPartitionName;

using android::fs_mgr::Interval;
@@ -1056,6 +1060,64 @@ TEST_F(SnapshotUpdateTest, ReclaimCow) { 
    }

}



class MetadataMountedTest : public SnapshotUpdateTest {

  public:

    void SetUp() override {

        metadata_dir_ = test_device->GetMetadataDir();

        ASSERT_TRUE(ReadDefaultFstab(&fstab_));

    }

    void TearDown() override {

        SetUp();

        // Remount /metadata

        test_device->set_recovery(false);

        EXPECT_TRUE(android::fs_mgr::EnsurePathMounted(&fstab_, metadata_dir_));

    }

    AssertionResult IsMetadataMounted() {

        Fstab mounted_fstab;

        if (!ReadFstabFromFile("/proc/mounts", &mounted_fstab)) {

            ADD_FAILURE() << "Failed to scan mounted volumes";

            return AssertionFailure() << "Failed to scan mounted volumes";

        }



        auto entry = GetEntryForPath(&fstab_, metadata_dir_);

        if (entry == nullptr) {

            return AssertionFailure() << "No mount point found in fstab for path " << metadata_dir_;

        }



        auto mv = GetEntryForMountPoint(&mounted_fstab, entry->mount_point);

        if (mv == nullptr) {

            return AssertionFailure() << metadata_dir_ << " is not mounted";

        }

        return AssertionSuccess() << metadata_dir_ << " is mounted";

    }

    std::string metadata_dir_;

    Fstab fstab_;

};



TEST_F(MetadataMountedTest, Android) {

    auto device = sm->EnsureMetadataMounted();

    EXPECT_NE(nullptr, device);

    device.reset();



    EXPECT_TRUE(IsMetadataMounted());

    EXPECT_TRUE(sm->CancelUpdate()) << "Metadata dir should never be unmounted in Android mode";

}



TEST_F(MetadataMountedTest, Recovery) {

    test_device->set_recovery(true);

    metadata_dir_ = test_device->GetMetadataDir();



    EXPECT_TRUE(android::fs_mgr::EnsurePathUnmounted(&fstab_, metadata_dir_));

    EXPECT_FALSE(IsMetadataMounted());



    auto device = sm->EnsureMetadataMounted();

    EXPECT_NE(nullptr, device);

    EXPECT_TRUE(IsMetadataMounted());



    device.reset();

    EXPECT_FALSE(IsMetadataMounted());

}



}  // namespace snapshot

}  // namespace android
@@ -1097,6 +1159,7 @@ int main(int argc, char** argv) { 
    }



    // Clean up previous run.

    MetadataMountedTest().TearDown();

    SnapshotUpdateTest().Cleanup();

    SnapshotTest().Cleanup();

fs_mgr/libsnapshot/test_helpers.h

+3 −0
Original line number Diff line number Diff line
@@ -88,17 +88,20 @@ class TestDeviceInfo : public SnapshotManager::IDeviceInfo { 
        return true;

    }

    bool IsOverlayfsSetup() const override { return false; }

    bool IsRecovery() const override { return recovery_; }



    void set_slot_suffix(const std::string& suffix) { slot_suffix_ = suffix; }

    void set_fake_super(const std::string& path) {

        opener_ = std::make_unique<TestPartitionOpener>(path);

    }

    void set_recovery(bool value) { recovery_ = value; }

    MergeStatus merge_status() const { return merge_status_; }



  private:

    std::string slot_suffix_ = "_a";

    std::unique_ptr<TestPartitionOpener> opener_;

    MergeStatus merge_status_;

    bool recovery_ = false;

};



class SnapshotTestPropertyFetcher : public android::fs_mgr::testing::MockPropertyFetcher {