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Commit 8e003772 authored by Yifan Hong's avatar Yifan Hong Committed by Automerger Merge Worker
Browse files

Merge "liblp: Force 10.0 metadata on downgrade to Q." into rvc-dev am:... 

Merge "liblp: Force 10.0 metadata on downgrade to Q." into rvc-dev am: 2ce3ddfe am: 91033bdb am: d393657b

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/12087943

Change-Id: Ie1ebc0ae79a9c5befa8213dbb90a061074c7bce8
parents 9752b428 d393657b

fs_mgr/liblp/builder.cpp

+12 −5
Original line number Diff line number Diff line
@@ -205,13 +205,20 @@ std::unique_ptr<MetadataBuilder> MetadataBuilder::NewForUpdate(const IPartitionO 
        }

    }



    if (IPropertyFetcher::GetInstance()->GetBoolProperty("ro.virtual_ab.enabled", false) &&

        !always_keep_source_slot) {

    if (IPropertyFetcher::GetInstance()->GetBoolProperty("ro.virtual_ab.enabled", false)) {

        if (always_keep_source_slot) {

            // always_keep_source_slot implies the target build does not support snapshots.

            // Clear unsupported attributes.

            SetMetadataHeaderV0(metadata.get());

        } else {

            // !always_keep_source_slot implies the target build supports snapshots. Do snapshot

            // updates.

            if (!UpdateMetadataForInPlaceSnapshot(metadata.get(), source_slot_number,

                                                  target_slot_number)) {

                return nullptr;

            }

        }

    }



    return New(*metadata.get(), &opener);

}

fs_mgr/liblp/include/liblp/builder.h

+4 −2
Original line number Diff line number Diff line
@@ -208,8 +208,10 @@ class MetadataBuilder { 
    // metadata may not have the target slot's devices listed yet, in which

    // case, it is automatically upgraded to include all available block

    // devices.

    // If |always_keep_source_slot| is set, on a Virtual A/B device, source slot

    // partitions are kept. This is useful when applying a downgrade package.

    // If |always_keep_source_slot| is set, on a Virtual A/B device

    // - source slot partitions are kept.

    // - UPDATED flag is cleared.

    // This is useful when applying a downgrade package.

    static std::unique_ptr<MetadataBuilder> NewForUpdate(const IPartitionOpener& opener,

                                                         const std::string& source_partition,

                                                         uint32_t source_slot_number,

fs_mgr/liblp/utility.cpp

+39 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
 */



#include <fcntl.h>

#include <inttypes.h>

#include <stdint.h>

#include <sys/stat.h>

#include <unistd.h>
@@ -29,6 +30,7 @@ 
#include <vector>



#include <android-base/file.h>

#include <android-base/stringprintf.h>

#include <ext4_utils/ext4_utils.h>

#include <openssl/sha.h>
@@ -285,5 +287,42 @@ bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot 
    return true;

}



inline std::string ToHexString(uint64_t value) {

    return android::base::StringPrintf("0x%" PRIx64, value);

}



void SetMetadataHeaderV0(LpMetadata* metadata) {

    if (metadata->header.minor_version <= LP_METADATA_MINOR_VERSION_MIN) {

        return;

    }

    LINFO << "Forcefully setting metadata header version " << LP_METADATA_MAJOR_VERSION << "."

          << metadata->header.minor_version << " to " << LP_METADATA_MAJOR_VERSION << "."

          << LP_METADATA_MINOR_VERSION_MIN;

    metadata->header.minor_version = LP_METADATA_MINOR_VERSION_MIN;

    metadata->header.header_size = sizeof(LpMetadataHeaderV1_0);



    // Retrofit Virtual A/B devices should have version 10.1, so flags shouldn't be set.

    // Warn if this is the case, but zero it out anyways.

    if (metadata->header.flags) {

        LWARN << "Zeroing unexpected flags: " << ToHexString(metadata->header.flags);

    }



    // Zero out all fields beyond LpMetadataHeaderV0.

    static_assert(sizeof(metadata->header) > sizeof(LpMetadataHeaderV1_0));

    memset(reinterpret_cast<uint8_t*>(&metadata->header) + sizeof(LpMetadataHeaderV1_0), 0,

           sizeof(metadata->header) - sizeof(LpMetadataHeaderV1_0));



    // Clear partition attributes unknown to V0.

    // On retrofit Virtual A/B devices, UPDATED flag may be set, so only log info here.

    for (auto& partition : metadata->partitions) {

        if (partition.attributes & ~LP_PARTITION_ATTRIBUTE_MASK_V0) {

            LINFO << "Clearing " << GetPartitionName(partition)

                  << " partition attribute: " << ToHexString(partition.attributes);

        }



        partition.attributes &= LP_PARTITION_ATTRIBUTE_MASK_V0;

    }

}



}  // namespace fs_mgr

}  // namespace android

fs_mgr/liblp/utility.h

+4 −0
Original line number Diff line number Diff line
@@ -103,6 +103,10 @@ bool SetBlockReadonly(int fd, bool readonly); 
bool UpdateMetadataForInPlaceSnapshot(LpMetadata* metadata, uint32_t source_slot_number,

                                      uint32_t target_slot_number);



// Forcefully set metadata header version to 1.0, clearing any incompatible flags and attributes

// so that when downgrading to a build with liblp V0, the device still boots.

void SetMetadataHeaderV0(LpMetadata* metadata);



}  // namespace fs_mgr

}  // namespace android