Re: [Chicken-users] daemonize egg: redirect I/O?

[Ozzi]

Thomas Christian Chust wrote:

> I think it would suffice for daemonize to wrap the call to the daemon's
> main procedure in a dynamic-wind block and call the cleanup function
> from the exit thunk. Unless the daemon procedure terminates itself with
> a low-level _exit or by sending itself a kill signal, the cleanup code
> should then always be executed.


Ok, I think I understand what you're getting it. Unfortunately I can't get it to 
work. You'll have to excuse the thrown-together quality of the code below, but 
it demonstrates the problem I have. Perhaps I am just mis-using dynamic-wind, or 
I have to use something besides (exit) when catching the kill signal, I'm not sure.

(use posix)

(define (silly-daemon)
  (dynamic-wind
      ;; Before: Create our test pid file. It's empty, that's ok.
      (lambda () (system "touch /tmp/test.pid"))
      ;; Proc: Sleep a bit.
      (lambda ()
        ;; Exit cleanly (?) on kill.
        (set-signal-handler! signal/term (lambda () (exit)))
        (sleep 5))
      ;; After: Delete our test pid file.
      (lambda () (system "rm /tmp/test.pid"))))

;; Start silly-daemon.
(let ((pid (process-fork silly-daemon)))
  ;; Wait long enough for silly-daemon to finish sleeping.
  (sleep 7)
  ;; See if it deleted the pid file.
  (if (file-exists? "/tmp/test.pid")
      (print "Failure!")
      (print "Success!")))

;; "Success!" is printed.

;; Start silly-daemon.
(let ((pid (process-fork silly-daemon)))
  ;; Wait a second, then...
  (sleep 1)
  ;; ...kill silly-daemon before it finishes sleeping.
  (system (format "kill ~a" pid))
  ;; Wait a second before...
  (sleep 1)
  ;; ...checking to see if it deleted the pid file.
  (if (file-exists? "/tmp/test.pid")
      (print "Failure!")
      (print "Success!")))

;; "Failure!" is printed.

Thomas Christian Chust wrote:
> Ozzi wrote:

> cu,
> Thomas