Add logging upon failure to edit SystemSettings

Add more logs about file state and file permission state upon failing to
read or write a Settings file. In the case of failing to create a parent
directory for the settings file, SettingsState will attempt to create
the folder with Files.createDirectories, which throws more informative
errors.

Bug: 119723324
Test: None
Change-Id: Iec8ed903e109558efc3a98906c68d1579b985232

Author: Nate Myren

packages/SettingsProvider/src/com/android/providers/settings/SettingsState.java

@@ -64,6 +64,8 @@
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
@@ -716,6 +718,23 @@ private void doWriteState() {
                 }
             } catch (Throwable t) {
                 Slog.wtf(LOG_TAG, "Failed to write settings, restoring backup", t);
+                if (t instanceof IOException) {
+                    // we failed to create a directory, so log the permissions and existence
+                    // state for the settings file and directory
+                    logSettingsDirectoryInformation(destination.getBaseFile());
+                    if (t.getMessage().contains("Couldn't create directory")) {
+                        // attempt to create the directory with Files.createDirectories, which
+                        // throws more informative errors than File.mkdirs.
+                        Path parentPath = destination.getBaseFile().getParentFile().toPath();
+                        try {
+                            Files.createDirectories(parentPath);
+                            Slog.i(LOG_TAG, "Successfully created " + parentPath);
+                        } catch (Throwable t2) {
+                            Slog.e(LOG_TAG, "Failed to write " + parentPath
+                                    + " with Files.writeDirectories", t2);
+                        }
+                    }
+                }
                 destination.failWrite(out);
             } finally {
                 IoUtils.closeQuietly(out);
@@ -729,6 +748,33 @@ private void doWriteState() {
         }
     }
 
+    private static void logSettingsDirectoryInformation(File settingsFile) {
+        File parent = settingsFile.getParentFile();
+        Slog.i(LOG_TAG, "directory info for directory/file " + settingsFile
+                + " with stacktrace ", new Exception());
+        File ancestorDir = parent;
+        while (ancestorDir != null) {
+            if (!ancestorDir.exists()) {
+                Slog.i(LOG_TAG, "ancestor directory " + ancestorDir
+                        + " does not exist");
+                ancestorDir = ancestorDir.getParentFile();
+            } else {
+                Slog.i(LOG_TAG, "ancestor directory " + ancestorDir
+                        + " exists");
+                Slog.i(LOG_TAG, "ancestor directory " + ancestorDir
+                        + " permissions: r: " + ancestorDir.canRead() + " w: "
+                        + ancestorDir.canWrite() + " x: " + ancestorDir.canExecute());
+                File ancestorParent = ancestorDir.getParentFile();
+                if (ancestorParent != null) {
+                    Slog.i(LOG_TAG, "ancestor's parent directory " + ancestorParent
+                            + " permissions: r: " + ancestorParent.canRead() + " w: "
+                            + ancestorParent.canWrite() + " x: " + ancestorParent.canExecute());
+                }
+                break;
+            }
+        }
+    }
+
     static void writeSingleSetting(int version, XmlSerializer serializer, String id,
             String name, String value, String defaultValue, String packageName,
             String tag, boolean defaultSysSet) throws IOException {
@@ -803,6 +849,7 @@ private void readStateSyncLocked() {
             in = new AtomicFile(mStatePersistFile).openRead();
         } catch (FileNotFoundException fnfe) {
             Slog.i(LOG_TAG, "No settings state " + mStatePersistFile);
+            logSettingsDirectoryInformation(mStatePersistFile);
             addHistoricalOperationLocked(HISTORICAL_OPERATION_INITIALIZE, null);
             return;
         }