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Date: Wed, 10 May 1995 16:02:45 -0700
From: Bill Paul <wpaul>
Message-Id: <199505102302.QAA08441@freefall.cdrom.com>
To: CVS-commiters, cvs-usrsbin
Subject: cvs commit: src/usr.sbin/ypbind ypbind.c
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wpaul       95/05/10 16:02:44

  Modified:    usr.sbin/ypbind  ypbind.c
  Log:
  Performace improvements/simplifications/cleanups:
  
  - Make the child process reaper signal-driven. (Previously, we called reaper()
    once a second each time we went through the select() loop. This was
    convenient, but inefficient.)
  
  - Increase main select() timeout from 1 second to 60 seconds and use
    this as the ping timer instead of using timestamps in the _dom_binding
    structure. This nd the reaper() change noted above makes ypbind a little
    less CPU-intensive.
  
  - Don't flag EINTR's from select() as errors since they will happen as a
    result of incoming SIGCHLD's interrupting select().
  
  - Prevent possible resource hogging. Currently we malloc() memory
    each time a user process asks us to establish a binding for a domain,
    but we never free it. This could lead to serious memory leakage if a
    'clever' user did something like ask ypwhich to check the bindings
    for domains 0.0.0.0.0.0.0.0.0.0 through 9.9.9.9.9.9.9.9.9.9 inclusive.
    (This would also make a mess out of the /var/yp/binding directory.)
  
    We now avoid this silliness by a) limiting the maximum number of
    simultaneous bindings we can manage to 200, and b) free()ing _dom_binding
    structures of secondary domains whose servers have stopped responding.
    We unlink the /var/yp/binding/domain.vers files for the free()ed
    domains too.
  
    (This is safe to do since a client can prod us into reestablishing the
    binding, at which time we'll simply allocate a new _dom_binding structure
    for it.)
  
    We keep count of the total number of domains. If asked to
    allocate more than the maximum, we return an error. I have yet to hear
    of anybody needing 200 simultaneous NIS bindings, so this should be
    enough. (I chose the number 200 arbitrarily. It can be increased if need
    be.)
  
  - Changed "server not responding"/"server OK" messages to display server
    IP addresses again since it looks spiffier.
  
  - Use daemon() to daemonify ourselves,
  
  - Added a SIGTERM handler that removes all binding files and unregisters
    the ypbind service from the portmapper when a SIGTERM in received.
  
  - The comment 'blow away everything in BINDINGDIR' has no associated code.
    Give it some: clean out /var/yp/binding at startup (if it exists).
  
  This completes my ypbind wishlist. Barring bug fixes, I shouldn't need to
  go poking around in here anymore. (Of course, this means I can start
  working on my ypserv whishlist now... :)