Re: [PATCH] compat: Add another rudimentary poll() emulation

On Thu, May 27, 2010 at 1:00 PM, Erik Faye-Lund
[off-list ref] wrote:

On Thu, May 27, 2010 at 12:10 PM, Jonathan Nieder [off-list ref] wrote:

quoted

Implement the subset of poll() semantics needed by git in terms of
select(), for use by the Interix port.  Inspired by commit 6ed807f
(Windows: A rudimentary poll() emulation, 2007-12-01).

A possible problem with this approach is that the maximum number of
file descriptors poll can handle limited by RLIMIT_NOFILE, whereas the
maximum number of file descriptors select can handle is limited by
FD_SETSIZE.

I don't think this is a big problem in reality, though - both values
seem to be pretty high in most implementations. And IIRC git-daemon is
the only one who needs more than 2, and it doesn't even check
RLIMIT_NOFILE.

To be clear: I think this strategy is the best option (at least for
non-Windows, where select() might be our only option).

But perhaps you should include a check along the lines of this:

if (nfds > FD_SETSIZE)
	return errno = EINVAL, error("poll: nfds must be below %d", FD_SETSIZE);

Just so we can know when the code fails :)

-- 
Erik "kusma" Faye-Lund