diff --git a/CMakeLists.txt b/CMakeLists.txt
index 044d868e978..446e030d5ba 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -614,3 +614,10 @@ if(WITH_SYSTEMD)
 endif()
 
 include(CTags)
+option(CTAG_EXCLUDES "Exclude files/directories when running ctag.")
+add_tags(ctags
+  SRC_DIR src
+  TAG_FILE tags
+  EXCLUDE_OPTS ${CTAG_EXCLUDES}
+  EXCLUDES "*.js")
+add_custom_target(tags DEPENDS ctags)
diff --git a/cmake/modules/CTags.cmake b/cmake/modules/CTags.cmake
index 7b0d9d0a9ea..7d40984f749 100644
--- a/cmake/modules/CTags.cmake
+++ b/cmake/modules/CTags.cmake
@@ -1,27 +1,37 @@
 find_program(CTAGS_EXECUTABLE ctags)
-if(CTAGS_EXECUTABLE)
-  set(src_dir "src")
-  set(tag_file ${src_dir}/tags)
-  execute_process(
-    COMMAND git config --file .gitmodules --get-regexp path
-    COMMAND awk "/${src_dir}/ { print $2 }"
-    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    OUTPUT_VARIABLE submodules
-    OUTPUT_STRIP_TRAILING_WHITESPACE)
-  string(REPLACE "\n" " " submodules ${submodules})
-  string(REPLACE "${src_dir}/" "--exclude=" excludes ${submodules})
-  # cmake will quote any embedded spaces when expanding ${excludes}
-  # in the command below, so, turn ${excludes} into a cmake List (separated
-  # by semicolons) to let the expansion below simply replace them with spaces
-  # again.
-  separate_arguments(excludes UNIX_COMMAND ${excludes})
-  add_custom_target(ctags
-    COMMAND ${CTAGS_EXECUTABLE} -R --c++-kinds=+p --fields=+iaS --extra=+q --exclude=*.js ${excludes}
-    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/${src_dir}
-    COMMENT "Building ctags file ${tag_file} (no submodules)"
+
+function(add_tags name)
+  cmake_parse_arguments(TAGS "" "SRC_DIR;TAG_FILE" "EXCLUDE_OPTS;EXCLUDES" ${ARGN})
+  set(excludes ${TAGS_EXCLUDES})
+  if(TAGS_EXCLUDE_OPTS)
+    # always respect EXCLUDES_OPTS
+    list(APPEND excludes ${TAGS_EXCLUDE_OPTS})
+  else()
+    # exclude the submodules under SRC_DIR by default
+    execute_process(
+      COMMAND git config --file .gitmodules --get-regexp path
+      COMMAND awk "/${TAGS_SRC_DIR}/ { print $2 }"
+      WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+      OUTPUT_VARIABLE submodules
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+    string(REPLACE "${TAGS_SRC_DIR}/" "" submodules ${submodules})
+    # cmake list uses ";" as the delimiter, so split the string manually
+    # before iterating in it.
+    string(REPLACE "\n" ";" submodules ${submodules})
+    list(APPEND excludes ${submodules})
+  endif()
+  message(STATUS "exclude following files under ${TAGS_SRC_DIR}: ${excludes}")
+  # add_custom_target() accepts a list after "COMMAND" keyword, so we should
+  # make exclude_arg a list, otherwise cmake will quote it. and ctags will
+  # take it as as a single argument.
+  foreach(exclude ${excludes})
+    list(APPEND exclude_args --exclude=${exclude})
+  endforeach()
+  add_custom_target(${name}
+    COMMAND ${CTAGS_EXECUTABLE} -R --c++-kinds=+p --fields=+iaS --extra=+q ${exclude_args}
+    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/${TAGS_SRC_DIR}
+    COMMENT "Building ctags file ${TAGS_TAG_FILE}"
     VERBATIM)
-  add_custom_target(tags
-    DEPENDS ctags)
-  set_source_files_properties(${CMAKE_SOURCE_DIR}/${tag_file} PROPERTIES
+  set_source_files_properties(${CMAKE_SOURCE_DIR}/${TAGS_TAG_FILE} PROPERTIES
     GENERATED true)
-endif(CTAGS_EXECUTABLE)
+endfunction()