Date: Fri, 25 Jul 1997 11:51:55 -0700 From: Julian Elischer <julian@whistle.com> To: "Richard Seaman, Jr." <lists@tar.com> Cc: "freebsd-current@freebsd.org" <freebsd-current@FreeBSD.ORG> Subject: Re: Whats happened to ping? Message-ID: <33D8F5CB.5E652F78@whistle.com> References: <199707251537.KAA28194@ns.tar.com>
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Richard Seaman, Jr. wrote: I'm to blame.. this is a side effect of something I did I also noticed another yesterday.. I must have coded this wromg because I thought I told it to only not count errors that were ENOBUFS (while in flood mode).. I'll check and fix if needed julian > > It seems that there have recently been changes to the sematics of > "ping -c N". Unless I'm mistaken, the old behavior was that "ping -c N" > meant try to send N packets. Now it means keep trying until N packets > are actually sent. > > The practical effect of this is that "ping -c N" might loop endlessly, > if, for example, the network is down and the sendto fails. An actual > example: > > # ping -c 1 -n -q 204.95.160.35 > PING 204.95.160.35 (204.95.160.35): 56 data bytes > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ping: sendto: Network is down > ^C > --- 204.95.160.35 ping statistics --- > 0 packets transmitted, 0 packets received, > > The problem with this is that if you put "ping -c N" in a script, > expecting it to return at some point, you can now effectively have > your script hang. Which, of course, is what happened to me. > > While I'm sure there are good reasons for the change, I wonder: > > a) If it wouldn't be a good idea to leave the "-c" option with > the old meaning, and have a new option for the new behaviour > > b) If you don't restore the old meaning, a lot of people who > depend on ping to return when using the "-c" option will > get burned when they upgrade to current. > > Now, if I'm the only one affected, I can certainly work around > this new behaviour. But, I wonder if there aren't others in the > same boat.
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