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         /* This call should reset any possible non-fatal errors that
  44            occured since last call to dl* functions */
  45         error = sys_dlerror();
  46
  47         if(!handle) {
  48                 int level = is_probe ? 3 : 0;
  49                 DEBUG(level, ("Error loading module '%s': %s\n", module_name, error ? error : ""));
  50                 return NT_STATUS_UNSUCCESSFUL;
  51         }
  52
  53         init = (init_module_function *)sys_dlsym(handle, "init_module");
  54
  55         /* we must check sys_dlerror() to determine if it worked, because
  56            sys_dlsym() can validly return NULL */
  57         error = sys_dlerror();
  58         if (error) {
  59                 DEBUG(0, ("Error trying to resolve symbol 'init_module' in %s: %s\n",
  60                           module_name, error));
  61                 return NT_STATUS_UNSUCCESSFUL;
  62         }
  63
  64         status = init();
  65
  66         DEBUG(2, ("Module '%s' loaded\n", module_name));
  67
  68         return status;
  69 }
  70
  71 NTSTATUS smb_load_module(const char *module_name)
  72 {
  73         return do_smb_load_module(module_name, False);
  74 }
  75
  76 /* Load all modules in list and return number of
  77  * modules that has been successfully loaded */
  78 int smb_load_modules(const char **modules)
  79 {
  80         int i;
  81         int success = 0;
  82
  83         for(i = 0; modules[i]; i++){
  84                 if(NT_STATUS_IS_OK(smb_load_module(modules[i]))) {
  85                         success++;
  86                 }
  87         }
  88
  89         DEBUG(2, ("%d modules successfully loaded\n", success));
  90
  91         return success;
  92 }
  93
  94 NTSTATUS smb_probe_module(const char *subsystem, const char *module)
  95 {
  96         pstring full_path;
  97
  98         /* Check for absolute path */
  99
 100         /* if we make any 'samba multibyte string'
 101            calls here, we break
 102            for loading string modules */
 103
 104         DEBUG(5, ("Probing module '%s'\n", module));
 105
 106         if (module[0] == '/')
 107                 return do_smb_load_module(module, True);
 108
 109         pstrcpy(full_path, lib_path(subsystem));
 110         pstrcat(full_path, "/");
 111         pstrcat(full_path, module);
 112         pstrcat(full_path, ".");
 113         pstrcat(full_path, shlib_ext());
 114
 115         DEBUG(5, ("Probing module '%s': Trying to load from %s\n", module, full_path));
 116
 117         return do_smb_load_module(full_path, True);
 118 }
 119
 120 #else /* HAVE_DLOPEN */
 121
 122 NTSTATUS smb_load_module(const char *module_name)
 123 {
 124         DEBUG(0,("This samba executable has not been built with plugin support\n"));
 125         return NT_STATUS_NOT_SUPPORTED;
 126 }
 127
 128 int smb_load_modules(const char **modules)
 129 {
 130         DEBUG(0,("This samba executable has not been built with plugin support\n"));
 131         return -1;
 132 }
 133
 134 NTSTATUS smb_probe_module(const char *subsystem, const char *module)
 135 {
 136         DEBUG(0,("This samba executable has not been built with plugin support, not probing\n"));
 137         return NT_STATUS_NOT_SUPPORTED;
 138 }
 139
 140 #endif /* HAVE_DLOPEN */
 141
 142 void init_modules(void)
 143 {
 144         /* FIXME: This can cause undefined symbol errors :
 145          *  smb_register_vfs() isn't available in nmbd, for example */
 146         if(lp_preload_modules())
 147                 smb_load_modules(lp_preload_modules());
 148 }
 149
 150
 151 /***************************************************************************
 152  * This Function registers a idle event
 153  *
 154  * the registered funtions are run periodically
 155  * and maybe shutdown idle connections (e.g. to an LDAP server)
 156  ***************************************************************************/
 157 static smb_event_id_t smb_idle_event_id = 1;
 158
 159 struct smb_idle_list_ent {
 160         struct smb_idle_list_ent *prev,*next;
 161         smb_event_id_t id;
 162         smb_idle_event_fn *fn;
 163         void *data;
 164         time_t interval;
 165         time_t lastrun;
 166 };
 167
 168 static struct smb_idle_list_ent *smb_idle_event_list = NULL;
 169
 170 smb_event_id_t smb_register_idle_event(smb_idle_event_fn *fn, void *data, time_t interval)
 171 {
 172         struct smb_idle_list_ent *event;
 173
 174         if (!fn) {
 175                 return SMB_EVENT_ID_INVALID;
 176         }
 177
 178         event = SMB_MALLOC_P(struct smb_idle_list_ent);
 179         if (!event) {
 180                 DEBUG(0,("malloc() failed!\n"));
 181                 return SMB_EVENT_ID_INVALID;
 182         }
 183         event->fn = fn;
 184         event->data = data;
 185         event->interval = interval;
 186         event->lastrun = 0;
 187         event->id = smb_idle_event_id++;
 188
 189         DLIST_ADD(smb_idle_event_list,event);
 190
 191         return event->id;
 192 }
 193
 194 BOOL smb_unregister_idle_event(smb_event_id_t id)
 195 {
 196         struct smb_idle_list_ent *event = smb_idle_event_list;
 197
 198         while(event) {
 199                 if (event->id == id) {
 200                         DLIST_REMOVE(smb_idle_event_list,event);
 201                         SAFE_FREE(event);
 202                         return True;
 203                 }
 204                 event = event->next;
 205         }
 206
 207         return False;
 208 }
 209
 210 void smb_run_idle_events(time_t now)
 211 {
 212         struct smb_idle_list_ent *event = smb_idle_event_list;
 213
 214         while (event) {
 215                 struct smb_idle_list_ent *next = event->next;
 216                 time_t interval;
 217
 218                 if (event->interval <= 0) {
 219                         interval = SMB_IDLE_EVENT_DEFAULT_INTERVAL;
 220                 } else if (event->interval >= SMB_IDLE_EVENT_MIN_INTERVAL) {
 221                         interval = event->interval;
 222                 } else {
 223                         interval = SMB_IDLE_EVENT_MIN_INTERVAL;
 224                 }
 225                 if (now >(event->lastrun+interval)) {
 226                         event->lastrun = now;
 227                         event->fn(&event->data,&event->interval,now);
 228                 }
 229                 event = next;
 230         }
 231
 232         return;
 233 }
 234
 235 /***************************************************************************
 236  * This Function registers a exit event
 237  *
 238  * the registered functions are run on exit()
 239  * and maybe shutdown idle connections (e.g. to an LDAP server)
 240  ***************************************************************************/
 241
 242 struct smb_exit_list_ent {
 243         struct smb_exit_list_ent *prev,*next;
 244         smb_event_id_t id;
 245         smb_exit_event_fn *fn;
 246         void *data;
 247 };
 248
 249 static struct smb_exit_list_ent *smb_exit_event_list = NULL;
 250
 251 smb_event_id_t smb_register_exit_event(smb_exit_event_fn *fn, void *data)
 252 {
 253         struct smb_exit_list_ent *event;
 254         static smb_event_id_t smb_exit_event_id = 1;
 255
 256         if (!fn) {
 257                 return SMB_EVENT_ID_INVALID;
 258         }
 259
 260         event = SMB_MALLOC_P(struct smb_exit_list_ent);
 261         if (!event) {
 262                 DEBUG(0,("malloc() failed!\n"));
 263                 return SMB_EVENT_ID_INVALID;
 264         }
 265         event->fn = fn;
 266         event->data = data;
 267         event->id = smb_exit_event_id++;
 268
 269         DLIST_ADD(smb_exit_event_list,event);
 270
 271         return event->id;
 272 }
 273
 274 BOOL smb_unregister_exit_event(smb_event_id_t id)
 275 {
 276         struct smb_exit_list_ent *event = smb_exit_event_list;
 277
 278         while(event) {
 279                 if (event->id == id) {
 280                         DLIST_REMOVE(smb_exit_event_list,event);
 281                         SAFE_FREE(event);
 282                         return True;
 283                 }
 284                 event = event->next;
 285         }
 286
 287         return False;
 288 }
 289
 290 void smb_run_exit_events(void)
 291 {
 292         struct smb_exit_list_ent *event = smb_exit_event_list;
 293         struct smb_exit_list_ent *tmp = NULL;
 294
 295         while (event) {
 296                 event->fn(&event->data);
 297                 tmp = event;
 298                 event = event->next;
 299                 /* exit event should only run one time :-)*/
 300                 SAFE_FREE(tmp);
 301         }
 302
 303         /* the list is empty now...*/
 304         smb_exit_event_list = NULL;
 305
 306         return;
 307 }