udev rules help

[Jacek Konieczny]

On 2016-08-31 07:28, Elan Ruusamäe wrote:
> i'm trying to write udev rule to start service when usb device is attached
>
> here's what i got. yet it doesn't work
>
> # grep add /etc/udev/rules.d/80-idcard.rules
> SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device",
> ENV{ID_MODEL}=="*Smart*Card*Reader*", RUN+="/sbin/service pcscd start"

What init do you use. This _might_ work with systemd, as 'service' just 
shcedules a systemd job, but won't work with rc-scripts, as udev rules 
are not allowed to start long running processes.

udev rules are not a place for starting daemons, which is well 
documented thing.

> i even tried something very simple:
> ACTION=="add", RUN+="/sbin/service pcscd start"
>
> that also didn't work (attaching device did not start the service), how
> to debug this?

Just don't do this. Switch to systemd and use systemd device 
dependencies in the .service file to start the service.

If you want to stick with rc-scripts, then wait for the device in the 
init script.

Jacek