init: do not load persistent properties from temporary /data

With full disk encryption, a temporary /data partition is mounted to
start a minimum subset of the frameworks.  Later, once /data can be
decrypted it is mounted again.  load_persist_props is called both when
the temporary /data partition is mounted and again after the real
/data is mounted; this is a mistake.

This change checks to see if we're a FDE device and if so, returns the
first time load_persist_props is called.

Test: boot bullhead (FDE) with and without boot pin and check that
      persistent properties are loaded
Test: boot sailfish (FBE) and check that persistent properties are loaded
Change-Id: I6ed725072bdb27d80bfa6575d0a4876b08c6a4bc
diff --git a/init/property_service.cpp b/init/property_service.cpp
index e07550a..f0e4d2e 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -690,6 +690,17 @@
  * has mounted /data.
  */
 void load_persist_props(void) {
+    // Devices with FDE have load_persist_props called twice; the first time when the temporary
+    // /data partition is mounted and then again once /data is truly mounted.  We do not want to
+    // read persistent properties from the temporary /data partition or mark persistent properties
+    // as having been loaded during the first call, so we return in that case.
+    std::string crypto_state = android::base::GetProperty("ro.crypto.state", "");
+    std::string crypto_type = android::base::GetProperty("ro.crypto.type", "");
+    if (crypto_state == "encrypted" && crypto_type == "block") {
+        static size_t num_calls = 0;
+        if (++num_calls == 1) return;
+    }
+
     load_override_properties();
     /* Read persistent properties after all default values have been loaded. */
     load_persistent_properties();