vtkSocket does not restart interupted call
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
While installing ParaView on Nautilus, http://www.nics.tennessee.edu/computing-resources/nautilus, I hit a bug in vtkSocket that prevents ParaView from running on this machine. While tracking this down I uncovered a couple related issues.
The main issue is that vtkSocket does not handle EINTR. EINTR occurs when a signal is caught by the application during a blocking socket call. While ParaView does not make use of signals they are used for asynchronous communication by some SGI specific libraries on Nautilus that are linked in with SGI MPI. Because Rank 0 pvserver spends quite a bit of its time blocked in socket calls it only takes a few 10s of seconds for EINTR to occur. When faced with EINTR ParaView silently exits leaving the user wondering what the heck happened. Which brings me to the second issue, a lack of error reporting in vtkSocket.
To solve the first issue vtkSocket has to handle EINTR. How EINTR should be handled depends on the specific socket call. For all calls except connect the call can simply be restarted. For EINTR during connect one can't restart the call on all unix, so instead one must block in a select call when connect fails with EINTR. To be portable across Unix one should handle EINTR in all socket calls, even simple ones like set/getsockopt.
The second issue of error reporting applies to all socket related errors in general, my feeling is that when a socket call fails vtkSocket should print a message using vtkErrorMacro, errno, and strerror(or windows equivalent) at the point of failure. I think this should be done inside vtkSocket because this is the only place one can safely assume errno has relevant information and vtkSocket has been implemented returning a single error code, -1, so that returning the real error code would change the API and break existing code, including ParaView. Not to mention that the values for error codes are apparently different on windows and unix.
I took a stab at fixing these issues, patches attached. I tested them on my workstation, nautilus, and laptop running xp. I ran a dashboard on my linux workstation and didn't see any related issues. Would someone at KW mind taking a look at the changes and see if it could be made permanent?
By the way after testing all socket calls for error returns I uncovered a third bug, vtkSocket::Close didn't set the descriptor ivar to -1 which resulted in vtkSocket::~vtkSocket calling close on a closed socket. Not a disasterous error, but this reinforces my opinion that the returns should be tested and error messages printed.