From 49327806062652db999f3f0a7f360edb3047791a Mon Sep 17 00:00:00 2001
From: Yifan Hong <elsk@google.com>
Date: Mon, 26 Nov 2018 14:59:09 -0800
Subject: SYSTEM_ROOT -> get_system_root

Add a get_system_root() function in roots.cpp
which returns / or /system based on fstab.
This factors out the 'if' check from recovery.cpp
and fsck_unshare_blocks.cpp.

Test: boot recovery, mount system
Bug: 118634720
Change-Id: If4947cba3a3f08dbe695fd2b50a9354cd302ee03
---
 fsck_unshare_blocks.cpp | 13 ++++---------
 recovery.cpp            | 11 ++---------
 roots.cpp               |  9 +++++++++
 roots.h                 |  2 ++
 4 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/fsck_unshare_blocks.cpp b/fsck_unshare_blocks.cpp
index 684958e38..b653d13ce 100644
--- a/fsck_unshare_blocks.cpp
+++ b/fsck_unshare_blocks.cpp
@@ -40,7 +40,6 @@
 
 static constexpr const char* SYSTEM_E2FSCK_BIN = "/system/bin/e2fsck_static";
 static constexpr const char* TMP_E2FSCK_BIN = "/tmp/e2fsck.bin";
-static constexpr const char* SYSTEM_ROOT = "/system";
 
 static bool copy_file(const char* source, const char* dest) {
   android::base::unique_fd source_fd(open(source, O_RDONLY));
@@ -121,14 +120,10 @@ bool do_fsck_unshare_blocks() {
   std::vector<std::string> partitions = { "/odm", "/oem", "/product", "/vendor" };
 
   // Temporarily mount system so we can copy e2fsck_static.
-  bool mounted = false;
-  if (volume_for_mount_point(SYSTEM_ROOT) == nullptr) {
-    mounted = ensure_path_mounted_at("/", "/mnt/system") != -1;
-    partitions.push_back("/");
-  } else {
-    mounted = ensure_path_mounted_at(SYSTEM_ROOT, "/mnt/system") != -1;
-    partitions.push_back(SYSTEM_ROOT);
-  }
+  std::string system_root = get_system_root();
+  bool mounted = ensure_path_mounted_at(system_root.c_str(), "/mnt/system");
+  partitions.push_back(system_root);
+
   if (!mounted) {
     LOG(ERROR) << "Failed to mount system image.";
     return false;
diff --git a/recovery.cpp b/recovery.cpp
index e17526a95..7e1fa43a6 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -78,7 +78,6 @@ static constexpr const char* CACHE_ROOT = "/cache";
 static constexpr const char* DATA_ROOT = "/data";
 static constexpr const char* METADATA_ROOT = "/metadata";
 static constexpr const char* SDCARD_ROOT = "/sdcard";
-static constexpr const char* SYSTEM_ROOT = "/system";
 
 // We define RECOVERY_API_VERSION in Android.mk, which will be picked up by build system and packed
 // into target_files.zip. Assert the version defined in code and in Android.mk are consistent.
@@ -837,14 +836,8 @@ static Device::BuiltinAction prompt_and_wait(Device* device, int status) {
       }
       case Device::MOUNT_SYSTEM:
         // the system partition is mounted at /mnt/system
-        if (volume_for_mount_point(SYSTEM_ROOT) == nullptr) {
-          if (ensure_path_mounted_at("/", "/mnt/system") != -1) {
-            ui->Print("Mounted /system.\n");
-          }
-        } else {
-          if (ensure_path_mounted_at(SYSTEM_ROOT, "/mnt/system") != -1) {
-            ui->Print("Mounted /system.\n");
-          }
+        if (ensure_path_mounted_at(get_system_root().c_str(), "/mnt/system") != -1) {
+          ui->Print("Mounted /system.\n");
         }
         break;
 
diff --git a/roots.cpp b/roots.cpp
index dc347848a..e68cb20bc 100644
--- a/roots.cpp
+++ b/roots.cpp
@@ -44,6 +44,7 @@
 
 static struct fstab* fstab = nullptr;
 static bool did_map_logical_partitions = false;
+static constexpr const char* SYSTEM_ROOT = "/system";
 
 extern struct selabel_handle* sehandle;
 
@@ -412,3 +413,11 @@ int setup_install_mounts() {
 bool logical_partitions_mapped() {
   return did_map_logical_partitions;
 }
+
+std::string get_system_root() {
+  if (volume_for_mount_point(SYSTEM_ROOT) == nullptr) {
+    return "/";
+  } else {
+    return SYSTEM_ROOT;
+  }
+}
diff --git a/roots.h b/roots.h
index 702af8de5..314eb5f26 100644
--- a/roots.h
+++ b/roots.h
@@ -55,4 +55,6 @@ int setup_install_mounts();
 
 bool logical_partitions_mapped();
 
+std::string get_system_root();
+
 #endif  // RECOVERY_ROOTS_H_
-- 
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