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Commit 9ccbab0d authored by Akilesh Kailash's avatar Akilesh Kailash
Browse files

libsnapshot_cow: Create snapshot patch for full OTA 



create_snapshot --target=$ANDROID_PRODUCT_OUT/product.img --compression="zstd"
Snapshot patch: product.patch created successfully

Snapshot patch: product.patch created successfully
$ ls -lh product.patch
-rw-r--r-- 1 akailash primarygroup 1.8G Sep 17 22:21 product.patch

Default compression set to lz4.

Bug: 299011882
Test: create_snapshot --target=$ANDROID_PRODUCT_OUT/product.img --compression="zstd"
Change-Id: I42845ccf5d55fddd2bdfc7dae92510d247bb71e6
Signed-off-by: default avatarAkilesh Kailash <akailash@google.com>
parent c55b2ad4

fs_mgr/libsnapshot/libsnapshot_cow/create_cow.cpp

+42 −18
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ class CreateSnapshot { 
     */

    std::string parsing_file_;

    bool create_snapshot_patch_ = false;

    bool incremental_ = true;



    const int kNumThreads = 6;

    const size_t kBlockSizeToRead = 1_MiB;
@@ -103,6 +104,7 @@ class CreateSnapshot { 
    bool ReadBlocks(off_t offset, const int skip_blocks, const uint64_t dev_sz);

    std::string ToHexString(const uint8_t* buf, size_t len);



    bool CreateSnapshotFullOta();

    bool CreateSnapshotFile();

    bool FindSourceBlockHash();

    bool PrepareParse(std::string& parsing_file, const bool createSnapshot);
@@ -144,6 +146,10 @@ CreateSnapshot::CreateSnapshot(const std::string& src_file, const std::string& t 
    if (!compression.empty()) {

        compression_ = compression;

    }



    if (src_file_.empty()) {

        incremental_ = false;

    }

}



bool CreateSnapshot::PrepareParse(std::string& parsing_file, const bool createSnapshot) {
@@ -259,10 +265,21 @@ bool CreateSnapshot::CreateSnapshotFile() { 
    return ParsePartition();

}



bool CreateSnapshot::CreateSnapshotFullOta() {

    if (!PrepareParse(target_file_, true)) {

        return false;

    }

    return ParsePartition();

}



/*

 * Creates snapshot patch file by comparing source.img and target.img

 */

bool CreateSnapshot::CreateSnapshotPatch() {

    if (!incremental_) {

        return CreateSnapshotFullOta();

    }



    if (!FindSourceBlockHash()) {

        return false;

    }
@@ -289,6 +306,7 @@ std::string CreateSnapshot::ToHexString(const uint8_t* buf, size_t len) { 


void CreateSnapshot::PrepareMergeBlock(const void* buffer, uint64_t block,

                                       std::string& block_hash) {

    if (incremental_) {

        if (std::memcmp(zblock_.get(), buffer, BLOCK_SZ) == 0) {

            std::lock_guard<std::mutex> lock(write_lock_);

            zero_blocks_.push_back(block);
@@ -306,6 +324,7 @@ void CreateSnapshot::PrepareMergeBlock(const void* buffer, uint64_t block, 
            }

            return;

        }

    }

    std::lock_guard<std::mutex> lock(write_lock_);

    replace_blocks_.push_back(block);

}
@@ -615,10 +634,10 @@ bool CreateSnapshot::ParsePartition() { 


constexpr char kUsage[] = R"(

NAME

    create_snapshot - Create snapshot patches by comparing two partition images

    create_snapshot - Create snapshot patches



SYNOPSIS

    create_snapshot --source=<source.img> --target=<target.img> --compression="<compression-algorithm"

    $create_snapshot --source=<source.img> --target=<target.img> --compression="<compression-algorithm"



    source.img -> Source partition image

    target.img -> Target partition image
@@ -639,7 +658,12 @@ int main(int argc, char* argv[]) { 
    ::gflags::SetUsageMessage(kUsage);

    ::gflags::ParseCommandLineFlags(&argc, &argv, true);



    if (FLAGS_source.empty() || FLAGS_target.empty()) {

    if (FLAGS_target.empty()) {

        LOG(INFO) << kUsage;

        return 0;

    }



    if (FLAGS_target.empty() && !FLAGS_source.empty()) {

        LOG(INFO) << kUsage;

        return 0;

    }