I am beginning to use the sd-bus library. I have been able to get a couple of
properties, MainPID and SubState.
I would like to use the Stop method. I am using cups as an example. This
commands shows that in thee Unit interface there is a Start and Stop method:
$ busctl introspect org.freedesktop.systemd1
/org/freedesktop/systemd1/unit/cups_2eservice
NAME TYPE SIGNATURE RESULT/VALUE FLAGS
org.freedesktop.systemd1.Unit interface - -
-
.Start method s o
-
.Stop method s o
-
Each has a signature of "s" I assume it takes one parameter of type string.
I have tried the sample on this page. Pasting it into a file and compiling and
running it works
great.
https://0pointer.net/blog/the-new-sd-bus-api-of-systemd.html
This sample starts the cups service by acccessing the systemd Manager and
calling StartUnit.
|/* Issue the method call and store the respons message in m */
r=sd_bus_call_method(bus, "org.freedesktop.systemd1",/* service to
contact */ "/org/freedesktop/systemd1",/* object path */
"org.freedesktop.systemd1.Manager",/* interface name */ "StartUnit",/*
method name */ &error,/* object to return error in */ &m,/* return
message on success */ "ss",/* input signature */ "cups.service",/* first
argument */ "replace");/* second argument */ It has a signature of "ss"
which I assume means the method takes 2 arguments each of a type string.
My question is for any given method how do I get what the arguments for
it are ? Like if I use Start what are valid values to pass for the one
argument? In StartUnit the first argument seems obvious with an example
to be the unit you want to start. I am not sure what the "replace" means
or what other strings would be valid. Again I am interested in the Stop
method specifically, but in general would like to know where I can get a
list of the arguments and possible values for any method. Thanks Chris |
