init: restorecon libsnapshot rollback indicator

The rollback indicator is created during first stage init and
is unlabeled. Need to restorecon it properly so that it can
be properly deleted by update_engine later.

Bug: 149956852
Bug: 150907679
Test: apply OTA, reboot, look at serial console
Change-Id: Ie954023b557865691fec2ae378145596bf1973a9
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index 32345d2..81f616c 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -125,6 +125,9 @@
     // might be needed to perform first-stage mounts.
     static bool IsSnapshotManagerNeeded();
 
+    // Helper function for second stage init to restorecon on the rollback indicator.
+    static std::string GetGlobalRollbackIndicatorPath();
+
     // Begin an update. This must be called before creating any snapshots. It
     // will fail if GetUpdateState() != None.
     bool BeginUpdate();
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 61fc2df..154b5d7 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -81,6 +81,7 @@
 using namespace std::string_literals;
 
 static constexpr char kBootIndicatorPath[] = "/metadata/ota/snapshot-boot";
+static constexpr char kRollbackIndicatorPath[] = "/metadata/ota/rollback-indicator";
 static constexpr auto kUpdateStateCheckInterval = 2s;
 
 // Note: IImageManager is an incomplete type in the header, so the default
@@ -1012,7 +1013,7 @@
 }
 
 std::string SnapshotManager::GetRollbackIndicatorPath() {
-    return metadata_dir_ + "/rollback-indicator";
+    return metadata_dir_ + "/" + android::base::Basename(kRollbackIndicatorPath);
 }
 
 void SnapshotManager::AcknowledgeMergeSuccess(LockedFile* lock) {
@@ -1469,6 +1470,10 @@
     return access(kBootIndicatorPath, F_OK) == 0;
 }
 
+std::string SnapshotManager::GetGlobalRollbackIndicatorPath() {
+    return kRollbackIndicatorPath;
+}
+
 bool SnapshotManager::NeedSnapshotsInFirstStageMount() {
     // If we fail to read, we'll wind up using CreateLogicalPartitions, which
     // will create devices that look like the old slot, except with extra
diff --git a/init/selinux.cpp b/init/selinux.cpp
index 2faa167..acbcbd6 100644
--- a/init/selinux.cpp
+++ b/init/selinux.cpp
@@ -66,6 +66,7 @@
 #include <android-base/unique_fd.h>
 #include <fs_avb/fs_avb.h>
 #include <libgsi/libgsi.h>
+#include <libsnapshot/snapshot.h>
 #include <selinux/android.h>
 
 #include "debug_ramdisk.h"
@@ -78,6 +79,7 @@
 using android::base::Timer;
 using android::base::unique_fd;
 using android::fs_mgr::AvbHandle;
+using android::snapshot::SnapshotManager;
 
 namespace android {
 namespace init {
@@ -538,6 +540,8 @@
     // adb remount, snapshot-based updates, and DSUs all create files during
     // first-stage init.
     selinux_android_restorecon("/metadata", SELINUX_ANDROID_RESTORECON_RECURSE);
+
+    selinux_android_restorecon(SnapshotManager::GetGlobalRollbackIndicatorPath().c_str(), 0);
 }
 
 int SelinuxKlogCallback(int type, const char* fmt, ...) {