[CRIU] [PATCH] Query Dirty Tracking support via RPC

[Adrian Reber]

On Thu, Oct 01, 2015 at 03:51:25PM +0300, Pavel Emelyanov wrote:
> On 09/28/2015 05:17 PM, Adrian Reber wrote:
> > From: Adrian Reber <areber at redhat.com>
> > 
> > There are still systems which do not support dirty memory tracking.
> > This offers an interface to query the dirty memory tracking
> > availability via RPC. This is in preparation of a p.haul change
> > which will use this RPC interface to automatically detect if
> > pre-dumps should be executed or not.
> 
> Yes, definitely needed change. Can we however slightly generalize it
> and introduce the CRIU_REQ_TYPE__FEATURE_CHECK and a message containing
> a set of optional bool something bits for individual features the
> requester wants to check. The responce can be the same message with
> the respective bits set to True when supported.

Sure, makes sense. Will provide a reworked patch.

		Adrian

> > Signed-off-by: Adrian Reber <areber at redhat.com>
> > ---
> >  cr-service.c       | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >  protobuf/rpc.proto |  2 ++
> >  2 files changed, 49 insertions(+)
> > 
> > diff --git a/cr-service.c b/cr-service.c
> > index 938ea9e..53ea6e2 100644
> > --- a/cr-service.c
> > +++ b/cr-service.c
> > @@ -32,6 +32,7 @@
> >  #include "security.h"
> >  #include "sockets.h"
> >  #include "irmap.h"
> > +#include "kerndat.h"
> >  
> >  #include "setproctitle.h"
> >  
> > @@ -723,10 +724,53 @@ static int chk_keepopen_req(CriuReq *msg)
> >  	else if (msg->type == CRIU_REQ_TYPE__CPUINFO_DUMP ||
> >  		 msg->type == CRIU_REQ_TYPE__CPUINFO_CHECK)
> >  		return 0;
> > +	else if (msg->type == CRIU_REQ_TYPE__DIRTY_TRACKING)
> > +		return 0;
> >  
> >  	return -1;
> >  }
> >  
> > +static int handle_dirty_tracking(int sk, CriuReq *msg)
> > +{
> > +	CriuResp resp = CRIU_RESP__INIT;
> > +	bool success = false;
> > +	int pid, status;
> > +
> > +	pid = fork();
> > +	if (pid < 0) {
> > +		pr_perror("Can't fork");
> > +		goto out;
> > +	}
> > +
> > +	if (pid == 0) {
> > +		int ret = 1;
> > +
> > +		if (setup_opts_from_req(sk, msg->opts))
> > +			goto cout;
> > +
> > +		setproctitle("dirty-tracking --rpc -D %s",
> > +			     images_dir);
> > +
> > +		kerndat_get_dirty_track();
> > +
> > +		if (kdat.has_dirty_track)
> > +			ret = 0;
> > +cout:
> > +		exit(ret);
> > +	}
> > +
> > +	wait(&status);
> > +	if (!WIFEXITED(status) || WEXITSTATUS(status))
> > +		goto out;
> > +
> > +	success = true;
> > +out:
> > +	resp.type = msg->type;
> > +	resp.success = success;
> > +
> > +	return send_criu_msg(sk, &resp);
> > +}
> > +
> >  static int handle_cpuinfo(int sk, CriuReq *msg)
> >  {
> >  	CriuResp resp = CRIU_RESP__INIT;
> > @@ -804,6 +848,9 @@ more:
> >  	case CRIU_REQ_TYPE__CPUINFO_CHECK:
> >  		ret = handle_cpuinfo(sk, msg);
> >  		break;
> > +	case CRIU_REQ_TYPE__DIRTY_TRACKING:
> > +		ret = handle_dirty_tracking(sk, msg);
> > +		break;
> >  
> >  	default:
> >  		send_criu_err(sk, "Invalid req");
> > diff --git a/protobuf/rpc.proto b/protobuf/rpc.proto
> > index 466780e..1f0e66e 100644
> > --- a/protobuf/rpc.proto
> > +++ b/protobuf/rpc.proto
> > @@ -115,6 +115,8 @@ enum criu_req_type {
> >  
> >  	CPUINFO_DUMP	= 7;
> >  	CPUINFO_CHECK	= 8;
> > +
> > +	DIRTY_TRACKING	= 9;
> >  }
> >  
> >  /*
> >