No worries. Do you want to commit that fix by itself, or should I?
On Thu, Aug 7, 2014 at 2:30 PM, Deepak Panickal <[email protected]> wrote: > Yeah, I had done that, thanks. > Just wanted to find out if it’s just us with the issue as didn’t see > anything mentioned on the list. > > On 7 Aug 2014, at 22:26, Zachary Turner <[email protected]> wrote: > > Ahh, I see. Can you just put an #ifdef _WIN32 that doesn't add the > pipe_fd to the fd_set for Windows? It's broken either way, but at least > this way it's less broken. > > > On Thu, Aug 7, 2014 at 2:25 PM, Deepak Panickal <[email protected]> > wrote: > >> Yes, we have a regression in behaviour. >> >> Before _pipe() was added, pipes were ignored on Windows. They were >> not added to the read_fds list for select(). So, the BytesAvailable() did >> not error. >> >> However, now since pipes are created, it is added to the read_fds list >> and then select() fails like you said, because it is not a socket. It fails >> with a WSAENOTSOCK error. Due to this, the BytesAvailable() errors out and >> no data is read from the remote socket connection. >> >> I only found this after the merge, as we were not able to read data from >> our remote debug stub. >> >> On 7 Aug 2014, at 22:15, Zachary Turner <[email protected]> wrote: >> >> Yes, that's correct. It's just that on Windows, select() won't accept a >> pipe, it will just return an error. Which we also don't handle correctly, >> it turns out, since we assume that the error it's returning is an errno, >> which on Windows it's not. >> >> That said, I'm pretty sure ConnectionFileDescriptor has never worked on >> Windows. Are you seeing a regression in behavior? i.e. something worked >> before you merged, but now it doesn't? >> >> >> On Thu, Aug 7, 2014 at 2:06 PM, Deepak Panickal <[email protected]> >> wrote: >> >>> Ah, so it is a known issue. Thanks, got it now. >>> We recently did a merge which brought in the new changes from upstream. >>> >>> Isn’t the ::select used in ConnectionFileDescriptor to wait till input >>> is available? >>> Not just from the command pipe, but also from the sockets. >>> >>> On 7 Aug 2014, at 21:38, Zachary Turner <[email protected]> wrote: >>> >>> Sorry, hit enter too soon. I have been thinking about next steps for >>> fixing this in the longer term. I think the way to go is that on Windows, >>> ConnectionFileDescriptor shouldn't even use select at all, nor should it >>> use the command pipe. The purpose of the command pipe seems to be so that >>> various interrupt commands can be sent to interrupt the select, and then >>> terminate the connection or something else so that it doesn't block forever. >>> >>> On Windows, the closest equivalent to select is WaitForMultipleObjects. >>> So I think on Windows we need to switch to using WFMO instead of select(). >>> The command pipe will be replaced by various event objects, which the user >>> will set according to which interruption command they want to send. WFMO >>> doesn't accept sockets though, so we need to call WSAEventSelect() to get >>> an event handle corresponding to read/write operations on the socket. >>> >>> There's numerous other portability issues with this class currently, >>> most notably that select() on windows doesn't set errno >>> >>> >>> On Thu, Aug 7, 2014 at 1:34 PM, Zachary Turner <[email protected]> >>> wrote: >>> >>>> This is a known issue. But I don't think this is a regression. It's >>>> just always been this way. Basically on Windows, select() only deals with >>>> sockets. It doesn't work with pipes, files, or anything else. In other >>>> words, ConnectionFileDescriptor is just fundamentally broken on Windows. I >>>> recently pushed a large refactor to the socket logic in >>>> ConnectionFileDescriptor which is aimed at addressing this. But it's only >>>> one step of what I think will be a long process to get >>>> ConnectionFileDescriptor working on Windows. >>>> >>>> >>>> On Thu, Aug 7, 2014 at 1:01 PM, Deepak Panickal <[email protected]> >>>> wrote: >>>> >>>>> Hi, >>>>> >>>>> I have been seeing an issue with the refactored pipe support changes >>>>> on Windows using _pipe(). >>>>> >>>>> This is specifically at the ::select function in >>>>> ConnectionFileDescriptor::BytesAvailable(). >>>>> On Windows, the ::select fails if the pipe file descriptor is also >>>>> included and so the connection fails. >>>>> >>>>> >>>>> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Core/ConnectionFileDescriptor.cpp?view=markup >>>>> >>>>> Wanted to ask if anybody else on Windows is seeing any such issue? >>>>> >>>>> Thanks, >>>>> Deepak >>>>> >>>>> >>>>> _______________________________________________ >>>>> lldb-dev mailing list >>>>> [email protected] >>>>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev >>>>> >>>> >>>> >>> >>> >> >> > >
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