OtaInfo.java

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import android.util.Base64;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;

public class OtaInfo {

	public static void pollOtaCerts(Map<String, JsonElement> results) {
		File keystore = new File("/system/etc/security/otacerts.zip");
		List<String> otaCerts = new ArrayList<>();
		ZipFile zip = null;
		try {
			zip = new ZipFile(keystore);
			Enumeration<? extends ZipEntry> entries = zip.entries();
			byte[] temp = new byte[4096];
			MessageDigest md = MessageDigest.getInstance("SHA-1");
			while (entries.hasMoreElements()) {
				InputStream is = zip.getInputStream((ZipEntry) entries.nextElement());
				md.reset();
				while (true) {
					int read = is.read(temp);
					if (read <= 0) {
						break;
					}
					md.update(temp, 0, read);
				}
				is.close();
				otaCerts.add(Base64.encodeToString(md.digest(), 2));
			}
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		} finally {
			if (zip != null)
				try {
					zip.close();
				} catch (IOException e) {
				}
		}

		JsonElement certs = SystemInfoApp.GSON.toJsonTree(otaCerts);

		File f = new File("/system/recovery-from-boot.p");

		boolean otaInstalled = f.exists();

		JsonObject ota = new JsonObject();
		ota.add("otaInstalled", new JsonPrimitive(otaInstalled));
		ota.add("certs", certs);

		results.put("otaInfo", ota);

	}
}