• Davide Libenzi's avatar
    [PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications · f348d70a
    Davide Libenzi authored
    Implement the half-closed devices notifiation, by adding a new POLLRDHUP
    (and its alias EPOLLRDHUP) bit to the existing poll/select sets.  Since the
    existing POLLHUP handling, that does not report correctly half-closed
    devices, was feared to be changed, this implementation leaves the current
    POLLHUP reporting unchanged and simply add a new bit that is set in the few
    places where it makes sense.  The same thing was discussed and conceptually
    agreed quite some time ago:
    
    http://lkml.org/lkml/2003/7/12/116
    
    Since this new event bit is added to the existing Linux poll infrastruture,
    even the existing poll/select system calls will be able to use it.  As far
    as the existing POLLHUP handling, the patch leaves it as is.  The
    pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing
    archs and sets the bit in the six relevant files.  The other attached diff
    is the simple change required to sys/epoll.h to add the EPOLLRDHUP
    definition.
    
    There is "a stupid program" to test POLLRDHUP delivery here:
    
     http://www.xmailserver.org/pollrdhup-test.c
    
    It tests poll(2), but since the delivery is same epoll(2) will work equally.
    Signed-off-by: default avatarDavide Libenzi <davidel@xmailserver.org>
    Cc: "David S. Miller" <davem@davemloft.net>
    Cc: Michael Kerrisk <mtk-manpages@gmx.net>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    f348d70a
poll.h 410 Bytes