[Mono-dev] Anonymous Pipe Stream Implementation
atsushieno at veritas-vos-liberabit.com
Tue Jul 16 09:45:09 UTC 2013
Thanks, that's quite a lot of effort :)
Whoever touches the runtime part should judge if making changes in the
runtime/icalls in this manner is acceptable. I'm particulary not sure
about using icalls from System.Core.dll.
Also we cannot expose any internal API as public, for example:
> Thanks for the feedback
> I started this project merely as an investigation into whether it was
> even possible to implement in unix, and so hadn't really thought far
> enough ahead as to sharing it. The code is now pushed to a fork on
> In terms of compatiblity i have not needed to change any existing dll
> references. At this point i have added two internal calls to the
> corlib\System.IO.MonoIO class. Perhaps you could look over these new
> internal calls and give a little more specific advice on what (if
> anything) needs conditioned out.
> I reused the poll() wrapper from the sockets implementation,
> (as MonoIO.PollFD) so i assume that is ok.
> I am re-using the existing CreatePipe() function for pipe
> creation, so that behaves the same as before.
> The GetPipeHandle() internal call just initializes a handle
> that was inherited from a parent process in mono's file descriptor
> table, which would not strike me as a compatibilty concern on it's own
> as it's only doing mono platform work.
> A new problem has presented itself, which some expert feedback would
> be appreciated. Based on the sample code:
> 1) Process.Start() is called on the server application to launch the
> client application
> 2) When the client application is started, it will inherit the pipe
> handle and eventually start using it
> 3) The server application calls DisposeLocalCopyOfClientHandle()
> 4) The server writes to the pipe
> There is a synchronization issue between when 2 and 3 run, because
> in my testing, sometimes the Process.Start() call has not fully
> completed launching the child process, and closing the client handle
> on the server side cause the pipe to be broken before the client is
> fully booted. Because the pipe is broken step 4 should fail, though
> right now this isn't quite happening :)
> With a Thread.Sleep(10) in DisposeLocalCopyOfClientHandle() the code
> seems to work about 50% of the time on my machine. With no sleep, the
> pipe seems to be broken every time.
> With the technical explanation out of the way, is there any way i
> could wait / yield, and force the Process.Start() to complete
> launching the client before DisploseLocalCopyOfClientHandle()
> complete? I can certainly find some threshold where Thread.Sleep()
> reliably fixes the issue on my machine, but it may not be nearly as
> reliable across platforms either, and may need to be pretty huge
> (multiple seconds maybe?) to really get good reliability that way.
> I also would still appreciate some feedback on the handle inheritance
> There aren't any tests yet, and i'm pretty severely violating the
> coding standards document at this point, so both of those things are
> still on my todo list. I'd also like to throw together the win32
> implementation as well (something that would be compatible with the
> MS.NET <http://MS.NET> implementation).
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