Ticket #12319: class_NetworktimeprefletAsAddon.cpp

//#pragma mark - class NetworktimeprefletAsAddon -


class NetworktimeprefletAsAddon
{
    /*
    This allows to invoke the /system/preferences/Time preflet.. Not with load_image()
    but outright with load_add_on() so that we can call its ntp_update_time() function directly.
    The source for that particular function is here:
        http://cgit.haiku-os.org/haiku/tree/src/preferences/time/ntp.cpp
    which is (in the original Time preflet) called from
        http://cgit.haiku-os.org/haiku/tree/src/preferences/time/NetworkTimeView.cpp
    */
    
public:

        NetworktimeprefletAsAddon();
        ~NetworktimeprefletAsAddon();
        
        void UpdateSystemTime();

private:  // CODE

    static status_t thread_func( void * );


private:  // DATA

        image_id  addonId;
        thread_id updaterThread;
};


NetworktimeprefletAsAddon::NetworktimeprefletAsAddon()
:   addonId( -1 ),
    updaterThread( -1 )
{
    addonId = load_add_on( "/system/preferences/Time" );
    if( addonId < B_OK )
    {
        printf( "** NetworktimeprefletAsAddon failure: can't load Time preflet: " );
        perror( strerror(addonId) );
    }
    //printf("addonId %ld\n", addonId);
}

NetworktimeprefletAsAddon::~NetworktimeprefletAsAddon()
{
    // make sure to kill the thread dead before we unload_add_on() the add-on
    // and its TEXT segment which the thread is running, or that will crash good! :
    
    if( updaterThread > 0 )
        kill_thread( updaterThread );
    
    if( addonId > 0 )
        unload_add_on( addonId );
}


void NetworktimeprefletAsAddon::UpdateSystemTime()
{
    status_t (*ntp_update_time)( const char *host, const char** errorString, int32* errorCode )
        = NULL
        ;
    status_t sta = get_image_symbol(
            addonId,
            "ntp_update_time__FPCcPPCcPl",  // "ntp_update_time" with some gcc2 name-mangling :-/
            B_SYMBOL_TYPE_TEXT,
            reinterpret_cast<void**>( &ntp_update_time )
            );
    //printf("func %p\n", ntp_update_time);
    
    if( sta != B_OK || NULL == ntp_update_time )
    {
        printf( "** NetworktimeprefletAsAddon: get_image_symbol failure: " );
        perror( strerror(sta) );
        
        //
        return;
        //
    }
    
    updaterThread = spawn_thread(
        thread_func, "(add-on)ntp_update_time",
        B_NORMAL_PRIORITY,
        ntp_update_time
        );
    resume_thread( updaterThread );
    
    // wait for (at most) 2 seconds:
    for( int i = 0; i < 20; i++ )
    {
        snooze( 100000 );
        
        // "resume_thread" is a good way to test if a thread is still running or not:
        status_t test = resume_thread( updaterThread );
        //printf( "0x%lx for updaterThread\n", test );
        if( B_BAD_THREAD_ID == test )
            // the thread has exited, no need to wait any longer
            return;
            //
    }
    
    // if we're here, we've waited for 2 seconds and the thread is STILL running...
    printf( "* NetworktimeprefletAsAddon: network thread stuck for too long, aborting (will try again later)\n" );
}

status_t NetworktimeprefletAsAddon::thread_func( void * func_inside_addon )
{
    // SUMMARY
    // - load settings BMessage
    // - call function
    
    status_t (*ntp_update_time)( const char *host, const char** errorString, int32* errorCode )
        = NULL
        ;
    (void*)ntp_update_time = func_inside_addon;
    
    const char * error_string = NULL;
    int32 error_code = 0;
    BString server;
    {
        // load "~/config/settings/networktime settings":
        EasyMessage system_settings;
        {
            BPath path;
            find_directory( B_USER_SETTINGS_DIRECTORY, &path );
            path.Append( "networktime settings" );
            
            system_settings.LoadFrom( path.Path() );
        }
        server = system_settings.String( "server" );  // server[0] contains e.g. "pool.ntp.org"
        
        // notes:
        // - passing "invalid.blah" results in message << NTP STATUS = 0x80006003 error_string=<Could not contact server> error_code=0x0 >>
        // - passing "invalid.com" stays stuck for many seconds (the invalid.com server probably fails to respond to our port probing..)
    }
    ;
    status_t status = ntp_update_time(
        server,
        &error_string,
        &error_code
        );
    
    if( B_OK != status )
        printf( "** NetworktimeprefletAsAddon status = 0x%lx error_string=<%s> error_code=0x%lx\n", status, error_string, error_code );
    
    return 0;
}