diff --git a/apexd/apex_file.cpp b/apexd/apex_file.cpp
new file mode 100644
index 0000000..2be4d26
--- /dev/null
+++ b/apexd/apex_file.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#include <android-base/logging.h>
+#include <ziparchive/zip_archive.h>
+#include <memory>
+#include <string>
+
+#include "apex_file.h"
+
+namespace android {
+namespace apex {
+
+std::unique_ptr<ApexFile> ApexFile::Open(const std::string& apex_filename) {
+  std::unique_ptr<ApexFile> ret(new ApexFile(apex_filename));
+  if (ret->OpenInternal() < 0) {
+    return nullptr;
+  }
+  return ret;
+}
+
+ApexFile::~ApexFile() {
+  if (handle_ != nullptr) {
+    CloseArchive(handle_);
+  }
+}
+
+static constexpr const char* kImageFilename = "image.img";
+
+int ApexFile::OpenInternal() {
+  if (handle_ != nullptr) {
+    // Already opened.
+    return 0;
+  }
+  int ret = OpenArchive(apex_filename_.c_str(), &handle_);
+  if (ret < 0) {
+    LOG(ERROR) << "Failed to open package " << apex_filename_ << ": "
+               << ErrorCodeString(ret);
+    return ret;
+  }
+
+  // Locate the mountable image within the zipfile and store offset and size.
+  ZipEntry entry;
+  ret = FindEntry(handle_, ZipString(kImageFilename), &entry);
+  if (ret < 0) {
+    LOG(ERROR) << "Could not find entry \"" << kImageFilename
+               << "\" in package " << apex_filename_ << ": "
+               << ErrorCodeString(ret);
+    return ret;
+  }
+  image_offset_ = entry.offset;
+  image_size_ = entry.uncompressed_length;
+  return 0;
+}
+
+}  // namespace apex
+}  // namespace android