lib/module.c

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/* 
   Unix SMB/CIFS implementation.
   module loading system

   Copyright (C) Jelmer Vernooij 2002-2003
   Copyright (C) Stefan (metze) Metzmacher 2003
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

#ifdef HAVE_DLOPEN

/* Load a dynamic module.  Only log a level 0 error if we are not checking 
   for the existence of a module (probling). */

static NTSTATUS do_smb_load_module(const char *module_name, BOOL is_probe)
{
        void *handle;
        init_module_function *init;
        NTSTATUS status;
        const char *error;

        /* Always try to use LAZY symbol resolving; if the plugin has 
         * backwards compatibility, there might be symbols in the 
         * plugin referencing to old (removed) functions
         */
        handle = sys_dlopen(module_name, RTLD_LAZY);

        /* This call should reset any possible non-fatal errors that 
           occured since last call to dl* functions */
        error = sys_dlerror();

        if(!handle) {
                int level = is_probe ? 3 : 0;
                DEBUG(level, ("Error loading module '%s': %s\n", module_name, error ? error : ""));
                return NT_STATUS_UNSUCCESSFUL;
        }

        init = (init_module_function *)sys_dlsym(handle, "init_module");

        /* we must check sys_dlerror() to determine if it worked, because
           sys_dlsym() can validly return NULL */
        error = sys_dlerror();
        if (error) {
                DEBUG(0, ("Error trying to resolve symbol 'init_module' in %s: %s\n", 
                          module_name, error));
                return NT_STATUS_UNSUCCESSFUL;
        }

        DEBUG(2, ("Module '%s' loaded\n", module_name));

        status = init();
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("Module '%s' initialization failed: %s\n",
                            module_name, get_friendly_nt_error_msg(status)));
        }

        return status;
}

NTSTATUS smb_load_module(const char *module_name)
{
        return do_smb_load_module(module_name, False);
}

/* Load all modules in list and return number of 
 * modules that has been successfully loaded */
int smb_load_modules(const char **modules)
{
        int i;
        int success = 0;

        for(i = 0; modules[i]; i++){
                if(NT_STATUS_IS_OK(smb_load_module(modules[i]))) {
                        success++;
                }
        }

        DEBUG(2, ("%d modules successfully loaded\n", success));

        return success;
}

NTSTATUS smb_probe_module(const char *subsystem, const char *module)
{
        pstring full_path;
        
        /* Check for absolute path */

        /* if we make any 'samba multibyte string' 
           calls here, we break 
           for loading string modules */

        DEBUG(5, ("Probing module '%s'\n", module));

        if (module[0] == '/')
                return do_smb_load_module(module, True);
        
        pstrcpy(full_path, lib_path(subsystem));
        pstrcat(full_path, "/");
        pstrcat(full_path, module);
        pstrcat(full_path, ".");
        pstrcat(full_path, shlib_ext());

        DEBUG(5, ("Probing module '%s': Trying to load from %s\n", module, full_path));
        
        return do_smb_load_module(full_path, True);
}

#else /* HAVE_DLOPEN */

NTSTATUS smb_load_module(const char *module_name)
{
        DEBUG(0,("This samba executable has not been built with plugin support\n"));
        return NT_STATUS_NOT_SUPPORTED;
}

int smb_load_modules(const char **modules)
{
        DEBUG(0,("This samba executable has not been built with plugin support\n"));
        return -1;
}

NTSTATUS smb_probe_module(const char *subsystem, const char *module)
{
        DEBUG(0,("This samba executable has not been built with plugin support, not probing\n")); 
        return NT_STATUS_NOT_SUPPORTED;
}

#endif /* HAVE_DLOPEN */

void init_modules(void)
{
        /* FIXME: This can cause undefined symbol errors :
         *  smb_register_vfs() isn't available in nmbd, for example */
        if(lp_preload_modules()) 
                smb_load_modules(lp_preload_modules());
}


/***************************************************************************
 * This Function registers a idle event
 *
 * the registered funtions are run periodically
 * and maybe shutdown idle connections (e.g. to an LDAP server)
 ***************************************************************************/
static smb_event_id_t smb_idle_event_id = 1;

struct smb_idle_list_ent {
        struct smb_idle_list_ent *prev,*next;
        smb_event_id_t id;
        smb_idle_event_fn *fn;
        void *data;
        time_t interval;
        time_t lastrun;
};

static struct smb_idle_list_ent *smb_idle_event_list = NULL;

smb_event_id_t smb_register_idle_event(smb_idle_event_fn *fn, void *data, time_t interval)
{
        struct smb_idle_list_ent *event;

        if (!fn) {      
                return SMB_EVENT_ID_INVALID;
        }

        event = SMB_MALLOC_P(struct smb_idle_list_ent);
        if (!event) {
                DEBUG(0,("malloc() failed!\n"));
                return SMB_EVENT_ID_INVALID;
        }
        event->fn = fn;
        event->data = data;
        event->interval = interval;
        event->lastrun = 0;
        event->id = smb_idle_event_id++;

        DLIST_ADD(smb_idle_event_list,event);

        return event->id;
}

BOOL smb_unregister_idle_event(smb_event_id_t id)
{
        struct smb_idle_list_ent *event = smb_idle_event_list;
        
        while(event) {
                if (event->id == id) {
                        DLIST_REMOVE(smb_idle_event_list,event);
                        SAFE_FREE(event);
                        return True;
                }
                event = event->next;
        }
        
        return False;
}

void smb_run_idle_events(time_t now)
{
        struct smb_idle_list_ent *event = smb_idle_event_list;

        while (event) {
                struct smb_idle_list_ent *next = event->next;
                time_t interval;

                if (event->interval <= 0) {
                        interval = SMB_IDLE_EVENT_DEFAULT_INTERVAL;
                } else if (event->interval >= SMB_IDLE_EVENT_MIN_INTERVAL) {
                        interval = event->interval;
                } else {
                        interval = SMB_IDLE_EVENT_MIN_INTERVAL;
                }
                if (now >(event->lastrun+interval)) {
                        event->lastrun = now;
                        event->fn(&event->data,&event->interval,now);
                }
                event = next;
        }

        return;
}

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