source/lib/module.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    module loading system
   4
   5    Copyright (C) Jelmer Vernooij 2002-2003
   6    Copyright (C) Stefan (metze) Metzmacher 2003
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 #ifdef HAVE_DLOPEN
  26
  27 /* Load a dynamic module.  Only log a level 0 error if we are not checking
  28    for the existence of a module (probling). */
  29
  30 static NTSTATUS do_smb_load_module(const char *module_name, BOOL is_probe)
  31 {
  32         void *handle;
  33         init_module_function *init;
  34         NTSTATUS status;
  35         const char *error;
  36
  37         /* Always try to use LAZY symbol resolving; if the plugin has
  38          * backwards compatibility, there might be symbols in the
  39          * plugin referencing to old (removed) functions
  40          */
  41         handle = sys_dlopen(module_name, RTLD_LAZY);
  42
  43         if(!handle) {
  44                 int level = is_probe ? 3 : 0;
  45                 error = sys_dlerror();
  46                 DEBUG(level, ("Error loading module '%s': %s\n", module_name, error ? error : ""));
  47                 return NT_STATUS_UNSUCCESSFUL;
  48         }
  49
  50         init = (init_module_function *)sys_dlsym(handle, "init_module");
  51
  52         /* we must check sys_dlerror() to determine if it worked, because
  53            sys_dlsym() can validly return NULL */
  54         error = sys_dlerror();
  55         if (error) {
  56                 DEBUG(0, ("Error trying to resolve symbol 'init_module' in %s: %s\n",
  57                           module_name, error));
  58                 return NT_STATUS_UNSUCCESSFUL;
  59         }
  60
  61         status = init();
  62
  63         DEBUG(2, ("Module '%s' loaded\n", module_name));
  64
  65         return status;
  66 }
  67
  68 NTSTATUS smb_load_module(const char *module_name)
  69 {
  70         return do_smb_load_module(module_name, False);
  71 }
  72
  73 /* Load all modules in list and return number of
  74  * modules that has been successfully loaded */
  75 int smb_load_modules(const char **modules)
  76 {
  77         int i;
  78         int success = 0;
  79
  80         for(i = 0; modules[i]; i++){
  81                 if(NT_STATUS_IS_OK(smb_load_module(modules[i]))) {
  82                         success++;
  83                 }
  84         }
  85
  86         DEBUG(2, ("%d modules successfully loaded\n", success));
  87
  88         return success;
  89 }
  90
  91 NTSTATUS smb_probe_module(const char *subsystem, const char *module)
  92 {
  93         pstring full_path;
  94
  95         /* Check for absolute path */
  96
  97         /* if we make any 'samba multibyte string'
  98            calls here, we break
  99            for loading string modules */
 100
 101         DEBUG(5, ("Probing module '%s'\n", module));
 102
 103         if (module[0] == '/')
 104                 return do_smb_load_module(module, True);
 105
 106         pstrcpy(full_path, lib_path(subsystem));
 107         pstrcat(full_path, "/");
 108         pstrcat(full_path, module);
 109         pstrcat(full_path, ".");
 110         pstrcat(full_path, shlib_ext());
 111
 112         DEBUG(5, ("Probing module '%s': Trying to load from %s\n", module, full_path));
 113
 114         return do_smb_load_module(full_path, True);
 115 }
 116
 117 #else /* HAVE_DLOPEN */
 118
 119 NTSTATUS smb_load_module(const char *module_name)
 120 {
 121         DEBUG(0,("This samba executable has not been built with plugin support\n"));
 122         return NT_STATUS_NOT_SUPPORTED;
 123 }
 124
 125 int smb_load_modules(const char **modules)
 126 {
 127         DEBUG(0,("This samba executable has not been built with plugin support\n"));
 128         return -1;
 129 }
 130
 131 NTSTATUS smb_probe_module(const char *subsystem, const char *module)
 132 {
 133         DEBUG(0,("This samba executable has not been built with plugin support, not probing\n"));
 134         return NT_STATUS_NOT_SUPPORTED;
 135 }
 136
 137 #endif /* HAVE_DLOPEN */
 138
 139 void init_modules(void)
 140 {
 141         /* FIXME: This can cause undefined symbol errors :
 142          *  smb_register_vfs() isn't available in nmbd, for example */
 143         if(lp_preload_modules())
 144                 smb_load_modules(lp_preload_modules());
 145 }
 146
 147
 148 /***************************************************************************
 149  * This Function registers a idle event
 150  *
 151  * the registered funtions are run periodically
 152  * and maybe shutdown idle connections (e.g. to an LDAP server)
 153  ***************************************************************************/
 154 static smb_event_id_t smb_idle_event_id = 1;
 155
 156 struct smb_idle_list_ent {
 157         struct smb_idle_list_ent *prev,*next;
 158         smb_event_id_t id;
 159         smb_idle_event_fn *fn;
 160         void *data;
 161         time_t interval;
 162         time_t lastrun;
 163 };
 164
 165 static struct smb_idle_list_ent *smb_idle_event_list = NULL;
 166
 167 smb_event_id_t smb_register_idle_event(smb_idle_event_fn *fn, void *data, time_t interval)
 168 {
 169         struct smb_idle_list_ent *event;
 170
 171         if (!fn) {
 172                 return SMB_EVENT_ID_INVALID;
 173         }
 174
 175         event = (struct smb_idle_list_ent *)malloc(sizeof(struct smb_idle_list_ent));
 176         if (!event) {
 177                 DEBUG(0,("malloc() failed!\n"));
 178                 return SMB_EVENT_ID_INVALID;
 179         }
 180         event->fn = fn;
 181         event->data = data;
 182         event->interval = interval;
 183         event->lastrun = 0;
 184         event->id = smb_idle_event_id++;
 185
 186         DLIST_ADD(smb_idle_event_list,event);
 187
 188         return event->id;
 189 }
 190
 191 BOOL smb_unregister_idle_event(smb_event_id_t id)
 192 {
 193         struct smb_idle_list_ent *event = smb_idle_event_list;
 194
 195         while(event) {
 196                 if (event->id == id) {
 197                         DLIST_REMOVE(smb_idle_event_list,event);
 198                         SAFE_FREE(event);
 199                         return True;
 200                 }
 201                 event = event->next;
 202         }
 203
 204         return False;
 205 }
 206
 207 void smb_run_idle_events(time_t now)
 208 {
 209         struct smb_idle_list_ent *event = smb_idle_event_list;
 210
 211         while (event) {
 212                 struct smb_idle_list_ent *next = event->next;
 213                 time_t interval;
 214
 215                 if (event->interval <= 0) {
 216                         interval = SMB_IDLE_EVENT_DEFAULT_INTERVAL;
 217                 } else if (event->interval >= SMB_IDLE_EVENT_MIN_INTERVAL) {
 218                         interval = event->interval;
 219                 } else {
 220                         interval = SMB_IDLE_EVENT_MIN_INTERVAL;
 221                 }
 222                 if (now >(event->lastrun+interval)) {
 223                         event->lastrun = now;
 224                         event->fn(&event->data,&event->interval,now);
 225                 }
 226                 event = next;
 227         }
 228
 229         return;
 230 }
 231
 232 /***************************************************************************
 233  * This Function registers a exit event
 234  *
 235  * the registered functions are run on exit()
 236  * and maybe shutdown idle connections (e.g. to an LDAP server)
 237  ***************************************************************************/
 238
 239 struct smb_exit_list_ent {
 240         struct smb_exit_list_ent *prev,*next;
 241         smb_event_id_t id;
 242         smb_exit_event_fn *fn;
 243         void *data;
 244 };
 245
 246 static struct smb_exit_list_ent *smb_exit_event_list = NULL;
 247
 248 smb_event_id_t smb_register_exit_event(smb_exit_event_fn *fn, void *data)
 249 {
 250         struct smb_exit_list_ent *event;
 251         static smb_event_id_t smb_exit_event_id = 1;
 252
 253         if (!fn) {
 254                 return SMB_EVENT_ID_INVALID;
 255         }
 256
 257         event = (struct smb_exit_list_ent *)malloc(sizeof(struct smb_exit_list_ent));
 258         if (!event) {
 259                 DEBUG(0,("malloc() failed!\n"));
 260                 return SMB_EVENT_ID_INVALID;
 261         }
 262         event->fn = fn;
 263         event->data = data;
 264         event->id = smb_exit_event_id++;
 265
 266         DLIST_ADD(smb_exit_event_list,event);
 267
 268         return event->id;
 269 }
 270
 271 BOOL smb_unregister_exit_event(smb_event_id_t id)
 272 {
 273         struct smb_exit_list_ent *event = smb_exit_event_list;
 274
 275         while(event) {
 276                 if (event->id == id) {
 277                         DLIST_REMOVE(smb_exit_event_list,event);
 278                         SAFE_FREE(event);
 279                         return True;
 280                 }
 281                 event = event->next;
 282         }
 283
 284         return False;
 285 }
 286
 287 void smb_run_exit_events(void)
 288 {
 289         struct smb_exit_list_ent *event = smb_exit_event_list;
 290         struct smb_exit_list_ent *tmp = NULL;
 291
 292         while (event) {
 293                 event->fn(&event->data);
 294                 tmp = event;
 295                 event = event->next;
 296                 /* exit event should only run one time :-)*/
 297                 SAFE_FREE(tmp);
 298         }
 299
 300         /* the list is empty now...*/
 301         smb_exit_event_list = NULL;
 302
 303         return;
 304 }