[systemd-devel] Requiring hardware device and escaping device names

Sun Mar 30 08:48:11 PDT 2014

On 26 March 2014 22:55, "Jóhann B. Guðmundsson" <johannbg at gmail.com> wrote:
> SUBSYSTEM=="input", ENV{ID_INPUT_KEYBOARD}=="?*", ENV{.INPUT_CLASS}="kbd",
> TAG+="systemd", ENV{SYSTEMD_WANTS}+="shkd@%p.service"

Trying to teach myself how to fish here. How did you know it would
match this particular device?

$ udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[290197.779159] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input7/event0
(input)
KERNEL[290197.788432] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input7
(input)
KERNEL[290197.791409] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0008/hidraw/hidraw0
(hidr
aw)
KERNEL[290197.799059] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0008
(hid)
KERNEL[290197.799463] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0 (usb)
KERNEL[290197.799878] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2 (usb)
UDEV  [290198.000420] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input7/event0
(input)
UDEV  [290198.019272] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0008/hidraw/hidraw0
(hidr
aw)
UDEV  [290198.028247] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input7
(input)
UDEV  [290198.033868] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0008
(hid)
UDEV  [290198.051687] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0 (usb)
UDEV  [290198.057794] remove
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2 (usb)
KERNEL[290199.905920] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2 (usb)
UDEV  [290199.916744] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2 (usb)
KERNEL[290199.918617] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0 (usb)
KERNEL[290199.926306] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0009
(hid)
KERNEL[290199.926697] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input8
(input)
KERNEL[290199.934673] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input8/event0
(input)
KERNEL[290199.936852] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0009/hidraw/hidraw0
(hidr
aw)
UDEV  [290199.979780] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0 (usb)
UDEV  [290200.026897] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0009
(hid)
UDEV  [290200.046996] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/0003:13BA:0001.0009/hidraw/hidraw0
(hidr
aw)
UDEV  [290200.059797] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input8
(input)
UDEV  [290200.121850] add
/devices/platform/bcm2708_usb/usb1/1-1/1-1.2/1-1.2.2/1-1.2.2:1.0/input/input8/event0
(input)

> /etc/systemd/system/shkd at .service
>
> [Unit]
> Description=Simple HotKey Daemon
>
> [Service]
> ExecStart=/usr/local/bin/shkd %I
> Restart=always
>
> [Install]
> WantedBy=multi-user.target

So IIUC, just have the udev rule there will start the systemd service.
No need to enable anything?

Anyway, it doesn't seem to work.

[hendry at alarmpi ~]$ systemctl | grep shk
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-event0.service
                              loaded failed     failed       Simple
HotKey Daemon
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.service
                                     loaded failed     failed
Simple HotKey Daemon
system-shkd.slice
                                                         loaded active
    active       system-shkd.slice
[hendry at alarmpi ~]$ sudo systemctl status
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-event0.service
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-event0.service
- Simple HotKey Daemon
   Loaded: loaded (/etc/systemd/system/shkd at .service; disabled)
   Active: failed (Result: start-limit) since Thu 1970-01-01 07:30:16
SGT; 44 years 2 months ago
  Process: 200 ExecStart=/usr/local/bin/shkd %I (code=exited, status=1/FAILURE)
 Main PID: 200 (code=exited, status=1/FAILURE)
Jan 01 07:30:16 alarmpi systemd[1]: Unit
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-ev...
state.
Jan 01 07:30:16 alarmpi systemd[1]:
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-event0....estart.
Jan 01 07:30:16 alarmpi systemd[1]: Stopping Simple HotKey Daemon...
Jan 01 07:30:16 alarmpi systemd[1]: Starting Simple HotKey Daemon...
Jan 01 07:30:16 alarmpi systemd[1]:
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-event0....
start.
Jan 01 07:30:16 alarmpi systemd[1]: Failed to start Simple HotKey Daemon.
Jan 01 07:30:16 alarmpi systemd[1]: Unit
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0-ev...
state.
Hint: Some lines were ellipsized, use -l to show in full.
[hendry at alarmpi ~]$ sudo systemctl status
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.service
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.service
- Simple HotKey Daemon
   Loaded: loaded (/etc/systemd/system/shkd at .service; disabled)
   Active: failed (Result: start-limit) since Thu 1970-01-01 07:30:16
SGT; 44 years 2 months ago
  Process: 199 ExecStart=/usr/local/bin/shkd %I (code=exited, status=1/FAILURE)
 Main PID: 199 (code=exited, status=1/FAILURE)
Jan 01 07:30:16 alarmpi systemd[1]:
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.service...FAILURE
Jan 01 07:30:16 alarmpi systemd[1]: Unit
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.se...
state.
Jan 01 07:30:16 alarmpi systemd[1]:
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.service...estart.
Jan 01 07:30:16 alarmpi systemd[1]: Stopping Simple HotKey Daemon...
Jan 01 07:30:16 alarmpi systemd[1]: Starting Simple HotKey Daemon...
Jan 01 07:30:16 alarmpi systemd[1]:
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.service...
start.
Jan 01 07:30:16 alarmpi systemd[1]: Failed to start Simple HotKey Daemon.
Jan 01 07:30:16 alarmpi systemd[1]: Unit
shkd at -devices-platform-bcm2708_usb-usb1-1-1-1-1.2-1-1.2.2-1-1.2.2:1.0-input-input0.se...
state.
Hint: Some lines were ellipsized, use -l to show in full.

Not sure what happened "/dev/input/by-id/usb-13ba_0001-event-kbd".

What is a slice?

Is there another forum for udev help? Many thanks,