Re: poll() emulation in git

From: Paolo Bonzini <bonzini@gnu.org>
Date: Sep 5, 2012, 12:05 UTC
Message-ID: <50474001.5030407@gnu.org>
In-Reply-To: <00c001cd8b59$028e41c0$07aac540$@schmitz-digital.de>

Il 05/09/2012 13:24, Joachim Schmitz ha scritto:

> However: this poll implementation, while compiling OK, doesn't work properly.
> Because it uses recv(...,MSG_PEEK), it works on sockets only (returns ENOTSOCK on anything else), while the real poll() works on all
> kind if file descriptors, at least that is my understanding.

Actually recv(...,MSG_PEEK) on most Unix variants works on non-sockets too. The trick is taken from GNU Pth in turn.

> Here on HP NonStop, when being connected via an non-interactive SSH, we get a set of pipes (stdin, stdout, stderr) instead of a
> socket to talk to, so the poll() just hangs/loops.

Does your system have a working FIONREAD ioctl for pipes?

Show 5 quoted lines

> As git's implementation is based on ('stolen' from?) gnulib's and still pretty similar, CC to the gnulib list and Paolo
> 
> Any idea how this could get solved? I.e. how to implement a poll() that works on non-sockets too?
> There is some code that pertains to a seemingly similar problem in Mac OS X, but my problem is not identical, as that fix doesn't
> help.

Paolo