Merge changes from topic "debug_ramdisk_path"

* changes:
  init: adding fallback paths for debug ramdisk
  init: loading debug resources before chroot into first_stage_ramdisk
diff --git a/init/first_stage_init.cpp b/init/first_stage_init.cpp
index 5cde167..84cda98 100644
--- a/init/first_stage_init.cpp
+++ b/init/first_stage_init.cpp
@@ -327,28 +327,22 @@
         LOG(INFO) << "Copied ramdisk prop to " << dest;
     }
 
-    if (ForceNormalBoot(cmdline, bootconfig)) {
-        mkdir("/first_stage_ramdisk", 0755);
-        // SwitchRoot() must be called with a mount point as the target, so we bind mount the
-        // target directory to itself here.
-        if (mount("/first_stage_ramdisk", "/first_stage_ramdisk", nullptr, MS_BIND, nullptr) != 0) {
-            LOG(FATAL) << "Could not bind mount /first_stage_ramdisk to itself";
-        }
-        SwitchRoot("/first_stage_ramdisk");
-    }
-
-    std::string force_debuggable("/force_debuggable");
+    // If "/force_debuggable" is present, the second-stage init will use a userdebug
+    // sepolicy and load adb_debug.prop to allow adb root, if the device is unlocked.
+    bool found_debuggable = false;
     std::string adb_debug_prop("/adb_debug.prop");
     std::string userdebug_sepolicy("/userdebug_plat_sepolicy.cil");
-    if (IsRecoveryMode()) {
-        // Update these file paths since we didn't switch root
-        force_debuggable.insert(0, "/first_stage_ramdisk");
+    if (access("/force_debuggable", F_OK) == 0) {
+        found_debuggable = true;
+    } else if (access("/first_stage_ramdisk/force_debuggable", F_OK) == 0) {
+        // Fallback to legacy debug resource paths.
+        // TODO(b/186485355): removes the fallback path once it is not needed.
+        found_debuggable = true;
         adb_debug_prop.insert(0, "/first_stage_ramdisk");
         userdebug_sepolicy.insert(0, "/first_stage_ramdisk");
     }
-    // If this file is present, the second-stage init will use a userdebug sepolicy
-    // and load adb_debug.prop to allow adb root, if the device is unlocked.
-    if (access(force_debuggable.c_str(), F_OK) == 0) {
+
+    if (found_debuggable) {
         std::error_code ec;  // to invoke the overloaded copy_file() that won't throw.
         if (!fs::copy_file(adb_debug_prop, kDebugRamdiskProp, ec) ||
             !fs::copy_file(userdebug_sepolicy, kDebugRamdiskSEPolicy, ec)) {
@@ -359,6 +353,16 @@
         }
     }
 
+    if (ForceNormalBoot(cmdline, bootconfig)) {
+        mkdir("/first_stage_ramdisk", 0755);
+        // SwitchRoot() must be called with a mount point as the target, so we bind mount the
+        // target directory to itself here.
+        if (mount("/first_stage_ramdisk", "/first_stage_ramdisk", nullptr, MS_BIND, nullptr) != 0) {
+            LOG(FATAL) << "Could not bind mount /first_stage_ramdisk to itself";
+        }
+        SwitchRoot("/first_stage_ramdisk");
+    }
+
     if (!DoFirstStageMount(!created_devices)) {
         LOG(FATAL) << "Failed to mount required partitions early ...";
     }