Messages in this thread | | | Date | Wed, 10 Sep 2008 11:10:16 -0700 | From | Andrew Morton <> | Subject | Re: paccept() oddity |
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On Wed, 20 Aug 2008 18:50:54 +0200 Michael Kerrisk <mtk.manpages@googlemail.com> wrote:
> Ulrich, > > [ > 2.6.27-rc has paccept(): > > int paccept(int fd, struct sockaddr *sockaddr, socklen_t *addrlen, > const sigset_t *sigmask, int setsize, int flags) > ] > > While considering the sigset argument for paccept() (see my previous > message), and testing that system call, I realized that there is a certain > oddness in the implementation of paccept(). > > Like accept(), paccept() automatically restarts if interrupted by a signal > handler that was established with the SA_RESTART flag. > > On the other hand, pselect(), ppoll(), and epoll_pwait() are never restarted > if interrupted by a handler, even if the handler was established with > SA_RESTART. (This is the same as with select(), poll(), and epoll_wait().) > > It seems to me that it makes little sense to restart paccept(), especially in > the case where it is interrupted by a handler for one of the signals that is > in sigmask, since the whole point of calling paccept() is to block until a > connection is received, or until one of the signals in sigmask is caught(). > > How about changing paccept() so that it is never automatically restarted if > interrupted by a signal handler, regardless of the SA_RESTART flag. (In > other words, paccept() should be consistent with pselect(), ppoll(), and > epoll_pwait(), rather than being consistent with accept().) What are your > thoughts? >
Oleg, Roland: would you have the time to ponder the above, please?
If we can't get this nailed down very soon I'd suggest that we disable sys_paccept() for 2.6.27. We don't want to be releasing a new system call into 2.6.27 if there are doubts surrounding its userspace-visible behaviour.
Thanks.
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