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Re: [hylafax-users] fax completely stuck

On 2005.02.03 15:10 Christian Schnobrich wrote:

Not recovering from a transfer error might justify a bug report.

Aye. However, it's complicated due to the way that HylaFAX works. faxsend is stuck sending the fax. And it's really stuck, waiting for a write() to return, which never will, because it's blocked. So faxsend cannot recover from the problem itself, alone.

In a better-designed faxsend there would be two permanent faxsend processes. The parent would do flow-control things and supervising of the child process, and it could monitor for when a write() or read() call gets blocked, and then kill the child when stuck. We already fork to do flow-control things, but it's a temporary fork, and we certainly wouldn't want to fork before each and every write() or read(). So, until faxsend gets redesigned faxsend cannot recover from the problem alone.

Now, there's faxq, but faxq doesn't really know what's going on with faxsend; faxsend and faxq do not communicate except at the faxsend startup and the exit status. In-between there's no communication. I guess that faxq would have a pretty good idea that faxsend were stuck if faxsend were running for a long, long time. The problem would be in defining "how long does it have to wait before it can say with certainty that faxsend is stuck". I've seen some faxes go for nearly an hour, without an error. So I'm reluctant to say that faxq has enough information to know what's going on.

Us humans, well, we see that it's not progressing, we look at the log, see that it's stuck, and then kill faxsend. I guess that you could create a cron job that did this for you.


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