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

1 files changed, 9 insertions, 0 deletions

diff --git a/roots.cpp b/roots.cpp
index dc347848..e68cb20b 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;
+  }
+}