Read global ASAN_OPTIONS from a file.

Instead of setting global ASAN_OPTIONS in immutable init.environ.rc,
load them from a file that can be changed later. The file has to be
on the /system partition to both be editable and available at the
early stages of boot.

Also add allocator_may_return_null=1 as that is closer to the
non-ASan allocator behavior.

Bug: 22846541
Change-Id: Ib0f41393c528f2e7cb398470e41f50abf5f4f455

rootdir/Android.mk

@@ -13,6 +13,20 @@ LOCAL_MODULE_PATH := $(TARGET_ROOT_OUT)
 
 include $(BUILD_PREBUILT)
 endif
+
+#######################################
+# asan.options
+ifeq (address,$(strip $(SANITIZE_TARGET)))
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := asan.options
+LOCAL_MODULE_CLASS := ETC
+LOCAL_SRC_FILES := $(LOCAL_MODULE)
+LOCAL_MODULE_PATH := $(TARGET_OUT)
+
+include $(BUILD_PREBUILT)
+endif
+
 #######################################
 # init.environ.rc
 
@@ -21,6 +35,11 @@ LOCAL_MODULE_CLASS := ETC
 LOCAL_MODULE := init.environ.rc
 LOCAL_MODULE_PATH := $(TARGET_ROOT_OUT)
 
+EXPORT_GLOBAL_ASAN_OPTIONS :=
+ifeq (address,$(strip $(SANITIZE_TARGET)))
+  EXPORT_GLOBAL_ASAN_OPTIONS := export ASAN_OPTIONS include=/system/asan.options
+  LOCAL_REQUIRED_MODULES := asan.options
+endif
 # Put it here instead of in init.rc module definition,
 # because init.rc is conditionally included.
 #
@@ -39,11 +58,6 @@ local_post_install_cmd_base :=
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
-EXPORT_GLOBAL_ASAN_OPTIONS :=
-ifeq (address,$(strip $(SANITIZE_TARGET)))
-  EXPORT_GLOBAL_ASAN_OPTIONS := export ASAN_OPTIONS allow_user_segv_handler=1:detect_odr_violation=0:alloc_dealloc_mismatch=0
-endif
-
 # Regenerate init.environ.rc if PRODUCT_BOOTCLASSPATH has changed.
 bcp_md5 := $(word 1, $(shell echo $(PRODUCT_BOOTCLASSPATH) $(PRODUCT_SYSTEM_SERVER_CLASSPATH) | $(MD5SUM)))
 bcp_dep := $(intermediates)/$(bcp_md5).bcp.dep

rootdir/asan.options

@@ -0,0 +1 @@
+allow_user_segv_handler=1:detect_odr_violation=0:alloc_dealloc_mismatch=0:allocator_may_return_null=1