Experimental Physics and
Industrial Control System

Hej Ralph,

I can see one (possible) problem here:
static void req_server (void *pParm)
{
    rsrv_iface_config *conf = pParm;
    SOCKET IOC_sock;

    taskwdInsert ( epicsThreadGetIdSelf (), NULL, NULL );

    IOC_sock = conf->tcp;

    /* listen and accept new connections */
    if ( listen ( IOC_sock, 20 ) < 0 ) {
        char sockErrBuf[64];
        epicsSocketConvertErrnoToString (
            sockErrBuf, sizeof ( sockErrBuf ) );
        errlogPrintf ( "CAS: Listen error: %s\n",
            sockErrBuf );
        epicsSocketDestroy (IOC_sock);
        epicsThreadSuspendSelf ();
    }

We should be able to print out errno,
to see what is going on and why listen fails.
(could be EAGAIN ??) We need to find out...



On 06/02/20 13:16, Ralph Lange via Core-talk wrote:

Dear Core-talkers,

We have been seeing an IOC lately that occasionally seems to boot fine, does not print the usual "cas warning: Configured TCP port was unavailable. [...]" messages for not being the first one on the host, but then emits a

CAS: Listen error: Address already in use
Thread CAS-TCP (0x3337a20) suspended

and becomes CA unresponsive.

We recently changed our IOC startup to be systemd controlled and are starting all IOCs in parallel. Question: Is there a vulnerability for a race condition where two IOCs are under the impression of being able to use the original CA port, but one of them eventually fails to listen()?

Cheers,
~Ralph

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Re: Weird CAS hangup on IOC Ralph Lange via Core-talk

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