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Re: poll() emulation in git
From: |
Paolo Bonzini |
Subject: |
Re: poll() emulation in git |
Date: |
Thu, 06 Sep 2012 16:31:44 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 |
Il 06/09/2012 16:02, Joachim Schmitz ha scritto:
>
> But is there something that could be done to make git work even without
> poll()?
> It is used in 5 places:
>
> $ grep -n poll\( *.c */*.c
> credential-cache--daemon.c:175: if (poll(&pfd, 1, 1000 * wakeup) < 0) {
> daemon.c:1018: if (poll(pfd, socklist->nr, -1) < 0) {
> help.c:361: poll(NULL, 0, autocorrect * 100);
> upload-pack.c:232: if (poll(pfd, pollsize, -1) < 0) {
> builtin/upload-archive.c:125: if (poll(pfd, 2, -1) < 0) {
>
> Don't quite understand why in help.c it has that NULL, which should always
> result in an EFAULT and other than that basically is a
> NOP (at least in the poll() emulation)? Seems a usleep(autocorrect * 100) is
> meant to happen here instead?
> So I think here a poll() isn't needed at all. But also the 'broken' one
> shouldn't harm too much.
Yes, it's an usleep(autocorrect * 100000) basically (poll takes
milliseconds, not micro).
> ...
> # else
> char data[64];
> r = recv (fd, data, sizeof (data), MSG_PEEK);
> socket_errno = (r < 0) ? errno : 0;
> # endif
> if (r == 0)
> happened |= POLLHUP;
>
> /* If the event happened on an unconnected server socket,
> that's fine. */
> else if (r > 0 || ( /* (r == -1) && */ socket_errno == ENOTCONN))
> happened |= (POLLIN | POLLRDNORM) & sought;
>
> /* Distinguish hung-up sockets from other errors. */
> else if (socket_errno == ESHUTDOWN || socket_errno == ECONNRESET
> || socket_errno == ECONNABORTED || socket_errno == ENETRESET)
> happened |= POLLHUP;
>
> #ifdef __TANDEM /* as we can't recv(...,MSG_PEEK) on a non-socket */
> else if (socket_errno == ENOTSOCK)
> happened |= (POLLIN | POLLRDNORM) & sought;
> #endif
> else
> happened |= POLLERR;
> }
> ...
>
> We won't detect POLLHUP that way I think. However it seems to work, we've
> been able to clone, push, pull, branch that way with
> NonStop being the (ssh-)server, something that didn't work at all without
> that hack (and yes, I believe it is just that).
> Someone in for a cleaner way of managing this?
I suppose it works to always handle ENOTSOCK that way, even on
non-__TANDEM systems.
Paolo
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/05
- Re: poll() emulation in git, Bastien ROUCARIES, 2012/09/05
- Re: poll() emulation in git, Paolo Bonzini, 2012/09/05
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/05
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/05
- Re: poll() emulation in git, Paolo Bonzini, 2012/09/05
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/06
- Re: poll() emulation in git,
Paolo Bonzini <=
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/06
- Re: poll() emulation in git, Paolo Bonzini, 2012/09/06
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/07
- RE: poll() emulation in git, Joachim Schmitz, 2012/09/07
- Re: poll() emulation in git, Paolo Bonzini, 2012/09/07