cvs commit: src/sys/fs/fifofs fifo_vnops.c

[Robert Watson]

rwatson     2005-09-12 19:59:12 UTC

  FreeBSD src repository

  Modified files:
    sys/fs/fifofs        fifo_vnops.c 
  Log:
  Introduce no-op nosup fifo kqueue filter and detach routine, which are
  used when a read filter is requested on a write-only fifo descriptor, or
  a write filter is requested on a read-only fifo descriptor.  This
  permits the filters to be registered, but never raises the event, which
  causes kqueue behavior for fifos to more closely match similar semantics
  for poll and select, which permit testing for the condition even though
  the condition will never be raised, and is consistent with POSIX's notion
  that a fifo has identical semantics to a one-way IPC channel created
  using pipe() on most operating systems.
  
  The fifo regression test suite can now run to completion on HEAD without
  errors.
  
  MFC after:      3 days
  
  Revision  Changes    Path
  1.121     +33 -1     src/sys/fs/fifofs/fifo_vnops.c