From 8b7af4c0ee245c913ae00dbf052c85156fb1b68e Mon Sep 17 00:00:00 2001
From: Jiyong Park <jiyong@google.com>
Date: Fri, 1 Jun 2018 11:58:54 +0900
Subject: Recovery image is self-contained

Now recovery mode is self-contained, which means we don't need to mount
system.img to run shell, etc. What is needed in recovery mode is all in
the recovery ramdisk image.

Since we no longer use /system as the mount point for the system.img,
this allows us to have identical filesystem layout as the system.img.
Executables and libs are installed to /system/bin and /system/lib.
Right now, we only have adbd, sh, toybox in /system/bin but will move
static executables from /sbin to /system/bin as soon as they are
converted to dynamic executables.

system.img is mounted to /mnt/system instead.

Bug: 63673171
Test: `adb reboot recovery; adb devices` shows the device ID
Test: `adb root && adb shell` and then
$ lsof -p `pidof adbd` shows that libm.so, libc.so, etc. are loaded from
the /lib directory.

Change-Id: I801ebd18f3e0a112db3d9a11e4fbb4e49181652a
---
 etc/init.rc             |  3 ++-
 fsck_unshare_blocks.cpp | 14 +++-----------
 recovery.cpp            |  8 +++-----
 3 files changed, 8 insertions(+), 17 deletions(-)

diff --git a/etc/init.rc b/etc/init.rc
index 0fc6c4c13..96c37b11c 100644
--- a/etc/init.rc
+++ b/etc/init.rc
@@ -22,6 +22,7 @@ on init
     mkdir /data
     mkdir /cache
     mkdir /sideload
+    mkdir /mnt/system
     mount tmpfs tmpfs /tmp
 
     chown root shell /tmp
@@ -87,7 +88,7 @@ service charger /charger -r
 service recovery /sbin/recovery
     seclabel u:r:recovery:s0
 
-service adbd /sbin/adbd --root_seclabel=u:r:su:s0 --device_banner=recovery
+service adbd /system/bin/adbd --root_seclabel=u:r:su:s0 --device_banner=recovery
     disabled
     socket adbd stream 660 system system
     seclabel u:r:adbd:s0
diff --git a/fsck_unshare_blocks.cpp b/fsck_unshare_blocks.cpp
index a100368e7..2e6b5b807 100644
--- a/fsck_unshare_blocks.cpp
+++ b/fsck_unshare_blocks.cpp
@@ -115,14 +115,6 @@ static bool run_e2fsck(const std::string& partition) {
   return true;
 }
 
-static const char* get_system_root() {
-  if (android::base::GetBoolProperty("ro.build.system_root_image", false)) {
-    return "/system_root";
-  } else {
-    return "/system";
-  }
-}
-
 bool do_fsck_unshare_blocks() {
   // List of partitions we will try to e2fsck -E unshare_blocks.
   std::vector<std::string> partitions = { "/odm", "/oem", "/product", "/vendor" };
@@ -130,10 +122,10 @@ bool do_fsck_unshare_blocks() {
   // Temporarily mount system so we can copy e2fsck_static.
   bool mounted = false;
   if (android::base::GetBoolProperty("ro.build.system_root_image", false)) {
-    mounted = ensure_path_mounted_at("/", "/system_root") != -1;
+    mounted = ensure_path_mounted_at("/", "/mnt/system") != -1;
     partitions.push_back("/");
   } else {
-    mounted = ensure_path_mounted("/system") != -1;
+    mounted = ensure_path_mounted_at("/system", "/mnt/system") != -1;
     partitions.push_back("/system");
   }
   if (!mounted) {
@@ -144,7 +136,7 @@ bool do_fsck_unshare_blocks() {
     LOG(ERROR) << "Could not copy e2fsck to /tmp.";
     return false;
   }
-  if (umount(get_system_root()) < 0) {
+  if (umount("/mnt/system") < 0) {
     PLOG(ERROR) << "umount failed";
     return false;
   }
diff --git a/recovery.cpp b/recovery.cpp
index 98cbfed2f..fea65ae9e 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -820,15 +820,13 @@ static Device::BuiltinAction prompt_and_wait(Device* device, int status) {
         break;
       }
       case Device::MOUNT_SYSTEM:
-        // For a system image built with the root directory (i.e. system_root_image == "true"), we
-        // mount it to /system_root, and symlink /system to /system_root/system to make adb shell
-        // work (the symlink is created through the build system). (Bug: 22855115)
+        // the system partition is mounted at /mnt/system
         if (android::base::GetBoolProperty("ro.build.system_root_image", false)) {
-          if (ensure_path_mounted_at("/", "/system_root") != -1) {
+          if (ensure_path_mounted_at("/", "/mnt/system") != -1) {
             ui->Print("Mounted /system.\n");
           }
         } else {
-          if (ensure_path_mounted("/system") != -1) {
+          if (ensure_path_mounted_at("/system", "/mnt/system") != -1) {
             ui->Print("Mounted /system.\n");
           }
         }
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