From bb968fb04db3ec5227e84571e1c6bfd265836085 Mon Sep 17 00:00:00 2001
From: Alex Deymo <deymo@google.com>
Date: Mon, 29 Feb 2016 17:23:36 -0800
Subject: [PATCH] Add /postinstall partition when using the A/B updater.

The new top level directory /postinstall is used by the A/B updater to
mount the new partition and run a post-install program before rebooting
into that new system.

init.rc was extended to label this new directory since the initrd has
no extended attributes.

Bug: 27177071
TEST=`ls -laZ /` shows the /postinstall directory on edison-eng

Change-Id: I6cdee7eb1d61ac7d447528962a4fad1a7bbf138d
---
 rootdir/Android.mk | 5 +++++
 rootdir/init.rc    | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/rootdir/Android.mk b/rootdir/Android.mk
index d90f988cc..d53af2ffe 100644
--- a/rootdir/Android.mk
+++ b/rootdir/Android.mk
@@ -70,6 +70,11 @@ ifdef BOARD_ROOT_EXTRA_SYMLINKS
     ; mkdir -p $(dir $(TARGET_ROOT_OUT)/$(word 2,$(p))) \
     ; ln -sf $(word 1,$(p)) $(TARGET_ROOT_OUT)/$(word 2,$(p)))
 endif
+# The A/B updater uses a top-level /postinstall directory to mount the new
+# system before reboot.
+ifeq ($(AB_OTA_UPDATER),true)
+  LOCAL_POST_INSTALL_CMD += ; mkdir -p $(TARGET_ROOT_OUT)/postinstall
+endif
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 1f63fcf74..2b1209978 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -23,6 +23,9 @@ on early-init
     # Shouldn't be necessary, but sdcard won't start without it. http://b/22568628.
     mkdir /mnt 0775 root system
 
+    # Set the security context of /postinstall if present.
+    restorecon /postinstall
+
     start ueventd
 
 on init