[LEDE-DEV] procd: service instance restart does not wait for old process to be closed before lanching the new one

[John Crispin]

On 08/02/2017 15:55, Alin Năstac wrote:
> Hi John,
> 
> One of the daemons I use takes sometime a couple of seconds to close
> after receiving SIGTERM, so when I issue "/etc/init.d/mydaemon
> restart" there will be 2 instances of that service running in parallel
> until the initial instance will finally manage to handle the SIGTERM
> signal. This daemon registers its own ubus object, but new instance
> will fail to register its object due to name conflict with an object
> that is already existing.
> 
> The root cause of this defect is the way procd restarts a service by
> issuing a service_stop followed immediately by a service_start:
>   1) service_stop call translates to
>     - instance_stop() ->  send SIGTERM signal to the old instance
>     - instance_free() -> call uloop_process_delete(), which means
> in->proc.pending will be set to 0
>   2) sevice_start will launch the new instance becaise previous
> process has been already deleted
> 
> Shouldn't uloop_process_delete() be called only when process was
> closed, as it is the case in uloop.c? If so, instance_start() should
> at least set restart to 1 when (in->proc.pending && in->halt).
> 
> And isn't a bit too optimistic to assume all daemons will be stopped by SIGTERM?

Hi,

probably, feel free to send a patch to fix the issue. we can help test it.

	John


> BR,
> Alin
> 
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