fprintd: ** Message: No devices in use, exit

Question

I keep getting following messages inside of /var/log/messages:

4/7/2016, 11:03:49 AM   fprintd[3277]   Launching FprintObject
4/7/2016, 11:03:49 AM   fprintd[3277]   ** Message: D-Bus service launched with name: net.reactivated.Fprint
4/7/2016, 11:03:49 AM   fprintd[3277]   ** Message: entering main loop
4/7/2016, 11:04:20 AM   fprintd[3277]   ** Message: No devices in use, exit

on following system:

$ cat /etc/redhat-release 
CentOS Linux release 7.2.1511 (Core) 
$ uname -a
Linux X 3.10.0-327.13.1.el7.x86_64 #1 SMP Thu Mar 31 16:04:38 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
$ 

even though service is disabled:

$ systemctl status fprintd
● fprintd.service - Fingerprint Authentication Daemon
   Loaded: loaded (/usr/lib/systemd/system/fprintd.service; static; vendor preset: disabled)
   Active: inactive (dead)
     Docs: man:fprintd(1)

Apr 07 11:05:27 X fprintd[4871]: Launching FprintObject
Apr 07 11:05:27 X fprintd[4871]: ** Message: D-Bus service launched with name: net.reactivated.Fprint
Apr 07 11:05:27 X fprintd[4871]: ** Message: entering main loop
Apr 07 11:05:58 X fprintd[4871]: ** Message: No devices in use, exit
Apr 07 11:18:22 X systemd[1]: Starting Fingerprint Authentication Daemon...
Apr 07 11:18:22 X systemd[1]: Started Fingerprint Authentication Daemon.
Apr 07 11:18:22 X fprintd[7010]: Launching FprintObject
Apr 07 11:18:22 X fprintd[7010]: ** Message: D-Bus service launched with name: net.reactivated.Fprint
Apr 07 11:18:22 X fprintd[7010]: ** Message: entering main loop
Apr 07 11:18:52 X fprintd[7010]: ** Message: No devices in use, exit
$ 

how do I REALLY disable, so this won't show up in my logs at all?

$ systemctl status dbus
● dbus.service - D-Bus System Message Bus
   Loaded: loaded (/usr/lib/systemd/system/dbus.service; static; vendor preset: disabled)
   Active: active (running) since Thu 2016-04-07 11:03:16 EDT; 57min ago
 Main PID: 904 (dbus-daemon)
   CGroup: /system.slice/dbus.service
           └─904 /bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation

Apr 07 11:14:35 X dbus[904]: [system] Successfully activated service 'org.freedesktop.hostname1'
Apr 07 11:14:35 X dbus-daemon[904]: dbus[904]: [system] Successfully activated service 'org.freedesktop.hostname1'
Apr 07 11:16:25 X dbus-daemon[904]: dbus[904]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 07 11:16:25 X dbus[904]: [system] Activating service name='org.freedesktop.problems' (using servicehelper)
Apr 07 11:16:25 X dbus[904]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 07 11:16:25 X dbus-daemon[904]: dbus[904]: [system] Successfully activated service 'org.freedesktop.problems'
Apr 07 11:18:22 X dbus-daemon[904]: dbus[904]: [system] Activating via systemd: service name='net.reactivated.Fprint' unit='fprintd.service'
Apr 07 11:18:22 X dbus[904]: [system] Activating via systemd: service name='net.reactivated.Fprint' unit='fprintd.service'
Apr 07 11:18:22 X dbus[904]: [system] Successfully activated service 'net.reactivated.Fprint'
Apr 07 11:18:22 X dbus-daemon[904]: dbus[904]: [system] Successfully activated service 'net.reactivated.Fprint'
$ 

I asked same question on CentOS board (fprintd: ** Message: No devices in use, exit - CentOS), however didn't get an answer, yet anyway..

Solution

This service is not "disabled", it is "static". This means it cannot normally be launched directly, but is launched by systemd in response to some event.

Since this service is meant to drive a fingerprint reader, it's a good bet that it will be fired during a console login attempt.

If you don't have a fingerprint reader and don't intend to ever have one, you can mask the service, so that it can never be started, even if it is uninstalled and reinstalled, and even if a dependency asks for it:

systemctl mask fprintd.service

The messages are (relatively) harmless and can be ignored, providing you have the extra few KB of disk space for storing them. If you do intend to have a fingerprint reader in future, you may wish to leave this service untouched, or at least carefully document that you have masked the service, so that future you remains aware of it.

Comments

[alexus]

+1 for such a great answer! it was driving me bananas:))

[alexus]

I mask service per your answer, however the outcome wasn't what I was expecting as I no longer was able to login into my system, even after I restart it, after ssh'ing to system and unmask service back and followed by reboot, I'm back in)

[Michael Hampton]

That's bad news? Well, if life gives you bananas, make a banana split :)

[alexus]

I went for banana sundae))