Check permissions of the destination directory before installing - c++

Question

I've been searching in the documentation and SO but I haven't found an answer for this issue.
Using cmake, I'm trying to check the permission of the DESTINATION directory before installing some libraries.
Is there some command in cmake to do this? Do I need to make the checks with custom commands?
As an example, this is my code in my CMakeLists.txt:
INSTALL( TARGETS ${LIBRARY_NAME}
DESTINATION lib/plugins/
PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE GROUP_READ GROUP_EXECUTE WORLD_READ WORLD_EXECUTE )
The idea is to check if the user has the required permissions to write in lib/plugins/ before installing the plugins.

Answer 1

You can use install(SCRIPT ...) command flow for execute some CMake script at install stage. For example:
check_script.cmake.in:
EXECUTE_PROCESS(COMMAND test -w #CMAKE_INSTALL_PREFIX#/lib/plugins
RESULT_VARIABLE res)
IF(res)
MESSAGE(FATAL_ERROR "No write permissions on plugins directory")
ENDIF()
CMakeLists.txt:
CONFIGURE_FILE(check_script.cmake.in check_script.cmake #ONLY)
INSTALL(SCRIPT ${CMAKE_CURRENT_BINARY_DIR}/check_script.cmake)
INSTALL( TARGETS ${LIBRARY_NAME} DESTINATION lib/plugins/ ...)
As you can see, it is too many work to check file permissions on install stage. Actually, you rarely need such checks: if installing of file fails, whole installation process stops immediately, and appropriate message is shown to the user.