| 1.4. Runlevel Editor Library | ||
|---|---|---|
 | Chapter 1. Modules and Libraries |  |
| 1.4. Runlevel Editor Library | ||
|---|---|---|
| | Chapter 1. Modules and Libraries | |
If you need to activate or de-activate services in YaST, use module Service. It is a replacement for the old client runlevel_adjust that you should have been using before You may also use it to obtain information about services. Following functions are self-containing.
Service::Adjust (string name,
string action) does some operation with init script.
name is the name of the init script.
action is one of:
"enable"
enables service, which means that if service is not set to run in any runlevel, it will set it to run in default runlevels. Otherwise it will not touch the service. Use it when you want the service to run, because it preserves user-defined state. If user sets service to run in some non-default runlevels, this will not destroy her own settings.
"disable"
disables service, which means that it sets it not to run in any runlevel.
"default"
sets service to run in its default runlevels, which are the runlevels listed in init script comment, fiels Default-Start.
"enable" and "disable" take no action when init script links are OK, but "default" always runs insserv.
Service::Adjust ("cups", "disable");
Service::Finetune
(string name, list rl)
sets service to run in list rl.
rl is list of strings.
Service::Finetune ("cups", [ "5" ]);
Service::Finetune ("cups", [ "S", "3", "5" ]);
Service::RunInitScript
(string name, string param)
runs init script name
with parameter param. Returns init scripts exit
value. I do not think it is worth to import module
Service only because of this one function when you
may simply call SCR::Execute (.target.bash, ...)
with the same result. But if you use Service for something else, this
function may increase readability of the code.
Service::RunInitScript ("cups", "restart");
Service::Status (string name),
Service::Info (string name) and
Service::FullInfo
(string name)
Service::Status tells whether service runs. It calls init script status and returns exit value.
Service::Info returns information about service. The map contains:
$[ "defstart" : [ ... ], // list of strings "defstop" : [ ... ], // list of default runlevels "start" : [ ... ], // list of strings "stop" : [ ... ], // list of real runlevels "reqstart" : [ ... ], // list of strings "reqstop" : [ ... ], // prerequisites "description": string,// description ]
Values "def{start|stop}", "req{start|stop}" and "description" are taken from init script comments. "start" and "stop" are taken from links. Service::FullInfo combines info from Service::Info and Service::Status into one map. It adds key "started" with integeral value of script status. Service is enabled if "start" is not empty.
Service::Enabled
(string name) returns true if service is set to run in any
runlevel. False otherwise.
![[Note]](../images/note.png)
import "Service";
boolean Read () {
if (0 != Service::RunInitScript ("foo", "restart"))
{
y2error ("Can not start service");
return false;
}
// ... your code ...
}
boolean Write () {
// ... write settings ...
// set service to correct state
if (start_it)
{
// enable service
Service::Adjust ("foo", "enable");
// reload changed settings
Service::RunInitScript ("foo", "reload");
}
else
{
// disable service
Service::Adjust ("foo", "disable");
// and stop it
Service::RunInitScript ("foo", "stop");
}
}It has sense to run some services only in case that some other service runs. Now the only case known to me is portmap that is needed by NFS, NIS and others. Runlevel UI cares about this case. But if you use functions like Service::Adjust, you must take care about these dependencies yourself. If you know about other dependencies, let me know, I will implement them in UI.
Just for your info: Runleve UI warns user who wants to stop service xdm. If you know about another cases where it is wise idea to warn user, please let us know...
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| 1.3. Advanced YaST2 command line parsing |  | UI Layout and Events |