Require a vendor_ prefix for users/groups in /vendor/etc/{passwd,group}

Bug: 79528966
Test: successful build with vendor_ prefixed users/groups
Test: expected build failure when not using vendor_ prefixed users/groups
Change-Id: If006c70178aa5bdcc9521a06ef8df2500f70bbb9
diff --git a/tools/fs_config/Android.mk b/tools/fs_config/Android.mk
index f946303..a01e702 100644
--- a/tools/fs_config/Android.mk
+++ b/tools/fs_config/Android.mk
@@ -254,7 +254,7 @@
 include $(BUILD_HEADER_LIBRARY)
 
 ##################################
-# Generate the system/etc/passwd text file for the target
+# Generate the vendor/etc/passwd text file for the target
 # This file may be empty if no AIDs are defined in
 # TARGET_FS_CONFIG_GEN files.
 include $(CLEAR_VARS)
@@ -270,10 +270,10 @@
 $(LOCAL_BUILT_MODULE): PRIVATE_ANDROID_FS_HDR := $(system_android_filesystem_config)
 $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/fs_config_generator.py $(TARGET_FS_CONFIG_GEN) $(system_android_filesystem_config)
 	@mkdir -p $(dir $@)
-	$(hide) $< passwd --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
+	$(hide) $< passwd --required-prefix=vendor_ --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
 
 ##################################
-# Generate the system/etc/group text file for the target
+# Generate the vendor/etc/group text file for the target
 # This file may be empty if no AIDs are defined in
 # TARGET_FS_CONFIG_GEN files.
 include $(CLEAR_VARS)
@@ -289,7 +289,7 @@
 $(LOCAL_BUILT_MODULE): PRIVATE_ANDROID_FS_HDR := $(system_android_filesystem_config)
 $(LOCAL_BUILT_MODULE): $(LOCAL_PATH)/fs_config_generator.py $(TARGET_FS_CONFIG_GEN) $(system_android_filesystem_config)
 	@mkdir -p $(dir $@)
-	$(hide) $< group --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
+	$(hide) $< group --required-prefix=vendor_ --aid-header=$(PRIVATE_ANDROID_FS_HDR) $(PRIVATE_TARGET_FS_CONFIG_GEN) > $@
 
 system_android_filesystem_config :=
 endif