Android/frameworks_base
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Use AtomicFile

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This should guarantee the integrity of the file content and
prevent the issue like b/170697897#comment2.

Bug: 170697897
Test: atest StagedRollbackTest
Change-Id: I4c2acb80fd9c806e31aa04d6defb480dafcf2c50
This commit is contained in:
JW Wang
2020-10-13 15:04:51 +08:00
parent e24a2c454e
commit ca07fd6d7c
1 changed files with 10 additions and 3 deletions
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13
services/core/java/com/android/server/rollback/RollbackStore.java
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@@ -25,6 +25,7 @@ import android.content.rollback.PackageRollbackInfo;
import android.content.rollback.PackageRollbackInfo.RestoreInfo;
import android.content.rollback.RollbackInfo;
import android.os.UserHandle;
import android.util.AtomicFile;
import android.util.Slog;
import android.util.SparseIntArray;
@@ -37,6 +38,7 @@ import org.json.JSONException;
import org.json.JSONObject;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.file.Files;
@@ -66,8 +68,6 @@ class RollbackStore {
//
// * XXX, YYY are the rollbackIds for the corresponding rollbacks.
// * rollback.json contains all relevant metadata for the rollback.
//
// TODO: Use AtomicFile for all the .json files?
private final File mRollbackDataDir;
RollbackStore(File rollbackDataDir) {
@@ -259,6 +259,8 @@ class RollbackStore {
* Saves the given rollback to persistent storage.
*/
static void saveRollback(Rollback rollback) {
FileOutputStream fos = null;
AtomicFile file = new AtomicFile(new File(rollback.getBackupDir(), "rollback.json"));
try {
JSONObject dataJson = new JSONObject();
dataJson.put("info", rollbackInfoToJson(rollback.info));
@@ -272,11 +274,16 @@ class RollbackStore {
dataJson.putOpt(
"extensionVersions", extensionVersionsToJson(rollback.getExtensionVersions()));
PrintWriter pw = new PrintWriter(new File(rollback.getBackupDir(), "rollback.json"));
fos = file.startWrite();
PrintWriter pw = new PrintWriter(fos);
pw.println(dataJson.toString());
pw.close();
file.finishWrite(fos);
} catch (JSONException | IOException e) {
Slog.e(TAG, "Unable to save rollback for: " + rollback.info.getRollbackId(), e);
if (fos != null) {
file.failWrite(fos);
}
}
}