From 6455f27e1b7f0bb7e59132f8b7f625d1dc460558 Mon Sep 17 00:00:00 2001
From: Yi-Yo Chiang <yochiang@google.com>
Date: Tue, 2 Nov 2021 21:37:03 +0800
Subject: [PATCH] Make clean_scratch_files work

clean_scratch_files.rc seems to never work as intended due to
missing domain transition rules.
Add a 'remount' domain to the platform policies to allow
remount-related operations, including clean_scratch_files.
Merge remount and clean_scratch_files binary to simplify the added
policies.

Bug: 204836146
Test: 1. Use a VAB device, for example bramble-userdebug
  2. adb remount system
  3. adb reboot fastboot && fastboot flash system system.img
  4. recovery (fastbootd) should mark the remount scratch as disabled
  5. fastboot reboot && adb shell mount | grep scratch => nothing
  6. adb logcat | grep 'clean_scratch_files|gsid' => shows that
    disabled image "scratch" is removed during boot
Change-Id: I18d543868d1f37d43b483eae7517b707e46df1bd
---
 fs_mgr/Android.bp                  | 22 +++-------------------
 fs_mgr/clean_scratch_files.cpp     | 22 ----------------------
 fs_mgr/fs_mgr_remount.cpp          | 16 ++++++++++++++++
 fs_mgr/libfiemap/image_manager.cpp |  7 ++++++-
 4 files changed, 25 insertions(+), 42 deletions(-)
 delete mode 100644 fs_mgr/clean_scratch_files.cpp

diff --git a/fs_mgr/Android.bp b/fs_mgr/Android.bp
index cb74ae09b..5872ddab6 100644
--- a/fs_mgr/Android.bp
+++ b/fs_mgr/Android.bp
@@ -246,28 +246,12 @@ cc_binary {
                 "-UALLOW_ADBD_DISABLE_VERITY",
                 "-DALLOW_ADBD_DISABLE_VERITY=1",
             ],
-        },
-    },
-    required: [
-        "clean_scratch_files",
-    ],
-}
-
-cc_binary {
-    name: "clean_scratch_files",
-    defaults: ["fs_mgr_defaults"],
-    shared_libs: [
-        "libbase",
-        "libfs_mgr_binder",
-    ],
-    srcs: [
-        "clean_scratch_files.cpp",
-    ],
-    product_variables: {
-        debuggable: {
             init_rc: [
                 "clean_scratch_files.rc",
             ],
         },
     },
+    symlinks: [
+        "clean_scratch_files",
+    ],
 }
diff --git a/fs_mgr/clean_scratch_files.cpp b/fs_mgr/clean_scratch_files.cpp
deleted file mode 100644
index 42fe35a59..000000000
--- a/fs_mgr/clean_scratch_files.cpp
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- * Copyright (C) 2020 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 <fs_mgr_overlayfs.h>
-
-int main() {
-    android::fs_mgr::CleanupOldScratchFiles();
-    return 0;
-}
diff --git a/fs_mgr/fs_mgr_remount.cpp b/fs_mgr/fs_mgr_remount.cpp
index bf53c1424..deaf5f72d 100644
--- a/fs_mgr/fs_mgr_remount.cpp
+++ b/fs_mgr/fs_mgr_remount.cpp
@@ -42,6 +42,8 @@
 #include <libavb_user/libavb_user.h>
 #include <libgsi/libgsid.h>
 
+using namespace std::literals;
+
 namespace {
 
 [[noreturn]] void usage(int exit_status) {
@@ -142,6 +144,7 @@ enum RemountStatus {
     BINDER_ERROR,
     CHECKPOINTING,
     GSID_ERROR,
+    CLEAN_SCRATCH_FILES,
 };
 
 static int do_remount(int argc, char* argv[]) {
@@ -163,6 +166,7 @@ static int do_remount(int argc, char* argv[]) {
             {"help", no_argument, nullptr, 'h'},
             {"reboot", no_argument, nullptr, 'R'},
             {"verbose", no_argument, nullptr, 'v'},
+            {"clean_scratch_files", no_argument, nullptr, 'C'},
             {0, 0, nullptr, 0},
     };
     for (int opt; (opt = ::getopt_long(argc, argv, "hRT:v", longopts, nullptr)) != -1;) {
@@ -183,6 +187,8 @@ static int do_remount(int argc, char* argv[]) {
             case 'v':
                 verbose = true;
                 break;
+            case 'C':
+                return CLEAN_SCRATCH_FILES;
             default:
                 LOG(ERROR) << "Bad Argument -" << char(opt);
                 usage(BADARG);
@@ -476,14 +482,24 @@ static int do_remount(int argc, char* argv[]) {
     return retval;
 }
 
+static int do_clean_scratch_files() {
+    android::fs_mgr::CleanupOldScratchFiles();
+    return 0;
+}
+
 int main(int argc, char* argv[]) {
     android::base::InitLogging(argv, MyLogger);
+    if (argc > 0 && android::base::Basename(argv[0]) == "clean_scratch_files"s) {
+        return do_clean_scratch_files();
+    }
     int result = do_remount(argc, argv);
     if (result == MUST_REBOOT) {
         LOG(INFO) << "Now reboot your device for settings to take effect";
         result = 0;
     } else if (result == REMOUNT_SUCCESS) {
         printf("remount succeeded\n");
+    } else if (result == CLEAN_SCRATCH_FILES) {
+        return do_clean_scratch_files();
     } else {
         printf("remount failed\n");
     }
diff --git a/fs_mgr/libfiemap/image_manager.cpp b/fs_mgr/libfiemap/image_manager.cpp
index dcbbc5448..2c14c8ac0 100644
--- a/fs_mgr/libfiemap/image_manager.cpp
+++ b/fs_mgr/libfiemap/image_manager.cpp
@@ -696,7 +696,12 @@ bool ImageManager::RemoveDisabledImages() {
     bool ok = true;
     for (const auto& partition : metadata->partitions) {
         if (partition.attributes & LP_PARTITION_ATTR_DISABLED) {
-            ok &= DeleteBackingImage(GetPartitionName(partition));
+            const auto name = GetPartitionName(partition);
+            if (!DeleteBackingImage(name)) {
+                ok = false;
+            } else {
+                LOG(INFO) << "Removed disabled partition image: " << name;
+            }
         }
     }
     return ok;