ASIO - Using IO service from main program in a .so loaded with dlopen, dlsym, etc.
Dear Community, I've got an application that loads a .so using dlopen, dlsym, etc. It also starts up an IO service pool and manages them. The application implements a socket server, that starts a thread for each incoming connection. Inside each of the threads started, a .so function is called based on information received on the socket. Inside the function of the .so, I want to connect to a remote server using the IO service in the main program (that called the dlopen, etc.). It seems, however, that if I use an IO service not created inside the .so, the handle_connect never gets called by ASIO. Is anyone aware of this problem. I suppose I'm just doing something stupid w.r.t. shared object usage (maybe permissions, etc.). Or is the ASIO library not initialised inside the DLL? When I create an IO service pool inside the .so, everything works, but obviously this is not ideal as the pool starts threads that execute the run() method on the io service. Interesting thing is that I can actually pass a session object (from the socket server accept operation) from my main program to the .so function and have messages read and written on the socket. But when I try and create a new connection using the session's IO service (e.g. from a sock.get_io_service() call), then I never get the handle_connect. I've even tried: #pragma GCC visibility push(default) #include <boost/asio.hpp> #include <boost/bind.hpp> #include <boost/thread.hpp> #pragma GCC visibility pop around the boost includes, but no luck. Any help on this would be greatly appreciated. Kind regards, Derik Thirion
J.W.F. Thirion wrote:
Interesting thing is that I can actually pass a session object (from the socket server accept operation) from my main program to the .so function and have messages read and written on the socket. But when I try and create a new connection using the session's IO service (e.g. from a sock.get_io_service() call), then I never get the handle_connect.
Does your main program export dynamic symbols (--export-dynamic in GNU ld) ? see here: http://www.nondot.org/~sabre/Mirrored/libtool-2.1a/libtool_9.html If for whatever reason the dynamically loaded code needs to resolve a symbol at runtime, and this has not been exported by your main program, I would expect the code to either be terminated with a runtime linker exception, or fail silently.
Hi there, Thanks. Let me expand a little here: I have a communication library, called libcomm. It has a session class that sends and receives messages on the socket (reads into a queue and writes from a queue). Users of the class simply call readMessage and writeMessage to access the queues and the library takes care of everything else. It also provides a connect function to connect to a remote server. In this class, I have all of the handleResolve, handleConnect, handleRead, handleWrite, etc. handlers. The session class inherits from enable_shared_from_this and makes use of shared_ptrs to make sure the object doesn't go out of scope with handlers outstanding. I also have a server class in this library that implements all of the functionality such as accepting connections, handleAccept, etc. A newly accepted connection results in a session object (which holds the underlying tcp socket). This appears to work correctly. The libcomm library is a libtool convenience library. I have linked the communication library statically into my main server program (that makes use of a server class in libcomm). I've also linked the library statically into my shared object, lets call it application.so. I am able to open (with dlopen) and load the main function in application.so with dlsym, I can even execute the main function in the .so. So in other words, I am able to resolve the symbol name in the shared object correctly. My main server program passes the session object from the server's accepted "session"/connection to the main function in the shared object application.so. Now I am able to continue reading /writing messages and have the handleRead and handleWrite on the session called through calls to async_read, etc. in libcomm from the shared object. It is just that new sessions created inside the shared object fails to have the handleConnect called. Hope this makes sense. Thanks for the help! Derik On Sat, 2009-08-29 at 13:53 +0100, Bruce Simpson wrote:
J.W.F. Thirion wrote:
Interesting thing is that I can actually pass a session object (from the socket server accept operation) from my main program to the .so function and have messages read and written on the socket. But when I try and create a new connection using the session's IO service (e.g. from a sock.get_io_service() call), then I never get the handle_connect.
Does your main program export dynamic symbols (--export-dynamic in GNU ld) ? see here: http://www.nondot.org/~sabre/Mirrored/libtool-2.1a/libtool_9.html
If for whatever reason the dynamically loaded code needs to resolve a symbol at runtime, and this has not been exported by your main program, I would expect the code to either be terminated with a runtime linker exception, or fail silently. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
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J.W.F. Thirion