brnstnd@stealth.acf.nyu.edu (05/25/90)
In article <1990May25.001614.23294@athena.mit.edu> jik@athena.mit.edu (Jonathan I. Kamens) writes: > In article <639@mecky.UUCP>, walter@mecky.UUCP (Walter Mecky) writes: > |> I think, a process in zombie state has no "valid pid" and kill(2) should > |> return -1. Am I wrong ? > Yes. A zombie process is still a process, even if it's in a weird > state. As long as that's true, it's still going to have a PID > associated with it, and therefore signals sent to it are going to work. You're correct up to the last phrase. Signals sent to it aren't going to ``work,'' in the sense that they won't invoke the usual signal handler; QUIT won't dump a zombie. They'll be delivered, but they won't work. ---Dan
jik@athena.mit.edu (Jonathan I. Kamens) (05/26/90)
In article <14276:May2508:53:0790@stealth.acf.nyu.edu>, brnstnd@stealth.acf.nyu.edu writes: |> In article <1990May25.001614.23294@athena.mit.edu> jik@athena.mit.edu |> (Jonathan I. Kamens) writes: |> > Yes. A zombie process is still a process, even if it's in a weird |> > state. As long as that's true, it's still going to have a PID |> > associated with it, and therefore signals sent to it are going to work. |> |> You're correct up to the last phrase. Signals sent to it aren't going to |> ``work,'' in the sense that they won't invoke the usual signal handler; |> QUIT won't dump a zombie. They'll be delivered, but they won't work. It's a matter of semantics; I stand by what I said, because I meant the same thing you did. The original poster said that he thought a kill(2) sent to a zombie process should return -1 (meaning that it "shouldn't work"). I replied that that's incorrect -- signals sent to a zombie process will "work", at least from the sender's point of view. Perhaps I should have said, "... and therefore sending signals to it is still going to work." Jonathan Kamens USnail: MIT Project Athena 11 Ashford Terrace jik@Athena.MIT.EDU Allston, MA 02134 Office: 617-253-8495 Home: 617-782-0710
gwyn@smoke.BRL.MIL (Doug Gwyn) (05/26/90)
In article <1990May25.181610.2342@athena.mit.edu> jik@athena.mit.edu (Jonathan I. Kamens) writes: >In article <14276:May2508:53:0790@stealth.acf.nyu.edu>, >brnstnd@stealth.acf.nyu.edu writes: >|> ... They'll be delivered, but they won't work. > It's a matter of semantics; I stand by what I said, because I meant >the same thing you did. I'm surprised you didn't point out that he also got it wrong. The signals are successfully posted but not never delivered.
brnstnd@stealth.acf.nyu.edu (05/28/90)
In article <13004@smoke.BRL.MIL> gwyn@smoke.BRL.MIL (Doug Gwyn) writes: > In article <1990May25.181610.2342@athena.mit.edu> jik@athena.mit.edu (Jonathan I. Kamens) writes: > > In article <14276:May2508:53:0790@stealth.acf.nyu.edu>, > > brnstnd@stealth.acf.nyu.edu writes: > > |> ... They'll be delivered, but they won't work. > > It's a matter of semantics; I stand by what I said, because I meant > > the same thing you did. > I'm surprised you didn't point out that he also got it wrong. > The signals are successfully posted but not never delivered. It's a matter of semantics; I stand by what I said, because I meant the same thing you did. :-) Actually, to match the terminology in the man pages (rather than anyone's particlar kernel), the signals are *sent* but never delivered. ---Dan