Android fanotify_init: Function not implemented

[Fabian B]

I'm trying to use fanotify on Android and like to archive that with an executable file (compiled with the ndk). I'm using fsmon (small application which calls the fanotify systemcall) to start the monitor. But on executing the file (on a rooted device as root) I'm getting following error:

generic_x86:/data/local/tmp # ./fsmon -B fanotify /storage/emulated/0/
fanotify_init: Function not implemented

fanotify is available in kernel version > 2.6.37 (which is shipped in Android 5+).

I had tried it on a x86-emulator (Android 7) and on a Samsung I9300 armeabi-v7a (Android 6) with CM13 (both rooted). Kernel version of the x86 emulator: 3.4.67+ and of the Samsung device: 3.0.101-CM-g9c98896

Then I had a look into the x86-emulator goldfish kernel files in /goldfish/fs/notify/fanotify/Kconfig:

config FANOTIFY
    bool "Filesystem wide access notification"
    select FSNOTIFY
    select ANON_INODES
    default n
    ---help---
       Say Y here to enable fanotify suport.  fanotify is a file access
       notification system which differs from inotify in that it sends
       an open file descriptor to the userspace listener along with
       the event.


       If unsure, say Y.


config FANOTIFY_ACCESS_PERMISSIONS
    bool "fanotify permissions checking"
    depends on FANOTIFY
    depends on SECURITY
    default n
    ---help---
       Say Y here is you want fanotify listeners to be able to make permissions
       decisions concerning filesystem events.  This is used by some fanotify
       listeners which need to scan files before allowing the system access to
       use those files.  This is used by some anti-malware vendors and by some
       hierarchical storage managent systems.


       If unsure, say N.

So, I set both to Y, make clean and recompile the kernel - but same problem like before.. Have I overlooked something?

[Fabian B]

Ok apparently was the fault to use an uppercase "Y" instead of a lowercase "y" ...