Re: libssh multi-threading issue

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Hi Anne,

Sorry nobody in libssh team is experienced in windows programming. The
concept is exactly the same, however there is no equivalent to
libssh-pthreads, you will have to implement the threading callbacks by
yourself. Feel free to take inspiration from
http://git.libssh.org/projects/libssh.git/tree/src/threads/pthread.c
I'm sure the windows code will be very similar.

Aris

Le 17/04/14 22:45, Anne Zhang a écrit :
> Any tips on how to get this working on windows? It will be very helpful.
>
> Thanks,
>
> Anne
>
>
> On Wed, Apr 16, 2014 at 6:58 PM, Anne Zhang <meantobe997@xxxxxxxxxxx
> <mailto:meantobe997@xxxxxxxxxxx>> wrote:
>
>     Hi Aris,
>
>     Thanks so much for the reply. It works in my Linux environment! I
>     tried:
>
>             static int initialized=0;
>     static pthread_mutex_t mutex1 = PTHREAD_MUTEX_INITIALIZER;
>     pthread_mutex_lock(&mutex1);
>     if (!initialized){
>     ssh_threads_set_callbacks(ssh_threads_get_pthread());
>     ssh_init();
>       initialized = 1;
>     }
>     pthread_mutex_unlock( &mutex1 );
>
>     So is there a similar mechanism in Windows? I noticed there is a
>     libssh_threads.so in libssh for linux but not for window.
>
>      What do I pass in ssh_threads_set_callbacks() for windows? Is
>     there anything i should notice for the build of libssh under windows?
>
>
>     On Wed, Apr 16, 2014 at 11:43 AM, Dustin Oprea
>     <myselfasunder@xxxxxxxxx <mailto:myselfasunder@xxxxxxxxx>> wrote:
>
>         On Wed, Apr 16, 2014 at 2:26 PM, Aris Adamantiadis
>         <aris@xxxxxxxxxxxx <mailto:aris@xxxxxxxxxxxx>> wrote:
>
>             Hi Anne,
>
>             There's an easy solution: before every ssh_connect, put an
>             initialization procedure protected by a mutex. This is not
>             optimal
>             (because every new connection will have to lock+unlock a
>             mutex) but you
>             are guaranteed that ssh_init gets called only once.
>
>
>         I like it. That's a cute solution for her requirements, Aris.
>
>
>
>         Dustin
>          
>
>             Pseudocode:
>
>             do_my_connect(){
>             static int initialized=0;
>             static mutex init_mutex;
>
>             mutex_lock(&init_mutex);
>             if (!initialized){
>               initialize_threading();
>               initialized = 1;
>             }
>             mutex_unlock(&init_mutex);
>
>
>             Regards,
>
>             Aris
>
>             Le 16/04/14 17:53, Anne Zhang a écrit :
>             > Hi Mike,
>             >
>             > Thanks for the reply. Unfortunately, I am only
>             implementing an .so
>             > file and have no access to the main program. I
>             understand ssh_init()
>             > would solve the problem but my library is being called
>             within a thread
>             > and I cannot change what's in the main/original thread.
>             >
>             > Look forward to additional input.
>             >
>             > Thanks,
>             >
>             > Anne
>             >
>             >
>             > On Wed, Apr 16, 2014 at 2:53 AM, Mike Jones
>             <mrjones@xxxxxxxxxx <mailto:mrjones@xxxxxxxxxx>
>             > <mailto:mrjones@xxxxxxxxxx <mailto:mrjones@xxxxxxxxxx>>>
>             wrote:
>             >
>             >     On 4/16/2014 1:51 AM, ZhangAnne wrote:
>             >>     Hi,
>             >>
>             >>     I am implementing a shared library, and met the
>             threading issue
>             >>     when the program calls my library and executes
>             multiple threads
>             >>     in parallel. Since my lib is being called by other
>             program, I
>             >>     cannot initialize the threading outside of any
>             threading context
>             >>     as mentioned
>             >>     here:
>             http://api.libssh.org/master/libssh_tutor_threads.html
>             >>
>             >>     My control to the code is limited within the scope
>             of my library.
>             >>     I am wondering if there is any workaround other
>             than changing
>             >>     code ouside my library?
>             >>
>             >>     Thanks,
>             >>
>             >>     Anne
>             >
>             >     If it helps, I used libssh in a multi-threaded
>             application without
>             >     calling ssh_threads_set_callbacks() or linking
>             libssh_threads.
>             >     In fact, I never even read this part of the libssh
>             documentation
>             >     before today. :)
>             >
>             >     The main/original thread of the application calls
>             ssh_init() and
>             >     then spawns off one additional thread that makes all
>             the other
>             >     libssh calls.
>             >     The freeing of resources and ssh_finalize() are done
>             back in the
>             >     original thread after this other thread has finished.
>             >
>             >     So far there have been no issues that I can
>             attribute to using it
>             >     this way.
>             >
>             >     We're running on Linux (RedHat 6.x) and using
>             libpthread.
>             >
>             >     - Mike
>             >
>             >
>             >
>             >
>
>
>
>
>