I need to use cutils library and headers to implement ashmem on my NDK project but I could not find anything related to cutils in my system. Where is it located or from where can I obtain it?
The Android "cutils" library, found in the sources at system/core/libcutils, is not part of the NDK. The code there changes with every release, so it's not something you can rely on.
The best approach for now is to copy the source for the relevant portions of the library into your project.