source3/libsmb/libsmb_cache.c

   1
   2 /*
   3    Unix SMB/CIFS implementation.
   4    SMB client library implementation (server cache)
   5    Copyright (C) Andrew Tridgell 1998
   6    Copyright (C) Richard Sharpe 2000
   7    Copyright (C) John Terpstra 2000
   8    Copyright (C) Tom Jansen (Ninja ISD) 2002
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26
  27 #include "include/libsmbclient.h"
  28 #include "../include/libsmb_internal.h"
  29
  30 int smbc_default_cache_functions(SMBCCTX * context);
  31
  32 /*
  33  * Structure we use if internal caching mechanism is used
  34  * nothing fancy here.
  35  */
  36 struct smbc_server_cache {
  37         char *server_name;
  38         char *share_name;
  39         char *workgroup;
  40         char *username;
  41         SMBCSRV *server;
  42
  43         struct smbc_server_cache *next, *prev;
  44 };
  45
  46
  47
  48 /*
  49  * Add a new connection to the server cache.
  50  * This function is only used if the external cache is not enabled
  51  */
  52 static int smbc_add_cached_server(SMBCCTX * context, SMBCSRV * newsrv,
  53                                   const char * server, const char * share,
  54                                   const char * workgroup, const char * username)
  55 {
  56         struct smbc_server_cache * srvcache = NULL;
  57
  58         if (!(srvcache = SMB_MALLOC_P(struct smbc_server_cache))) {
  59                 errno = ENOMEM;
  60                 DEBUG(3, ("Not enough space for server cache allocation\n"));
  61                 return 1;
  62         }
  63
  64         ZERO_STRUCTP(srvcache);
  65
  66         srvcache->server = newsrv;
  67
  68         srvcache->server_name = SMB_STRDUP(server);
  69         if (!srvcache->server_name) {
  70                 errno = ENOMEM;
  71                 goto failed;
  72         }
  73
  74         srvcache->share_name = SMB_STRDUP(share);
  75         if (!srvcache->share_name) {
  76                 errno = ENOMEM;
  77                 goto failed;
  78         }
  79
  80         srvcache->workgroup = SMB_STRDUP(workgroup);
  81         if (!srvcache->workgroup) {
  82                 errno = ENOMEM;
  83                 goto failed;
  84         }
  85
  86         srvcache->username = SMB_STRDUP(username);
  87         if (!srvcache->username) {
  88                 errno = ENOMEM;
  89                 goto failed;
  90         }
  91
  92         DLIST_ADD((context->server_cache), srvcache);
  93         return 0;
  94
  95  failed:
  96         SAFE_FREE(srvcache->server_name);
  97         SAFE_FREE(srvcache->share_name);
  98         SAFE_FREE(srvcache->workgroup);
  99         SAFE_FREE(srvcache->username);
 100         SAFE_FREE(srvcache);
 101
 102         return 1;
 103 }
 104
 105
 106
 107 /*
 108  * Search the server cache for a server
 109  * returns server handle on success, NULL on error (not found)
 110  * This function is only used if the external cache is not enabled
 111  */
 112 static SMBCSRV * smbc_get_cached_server(SMBCCTX * context, const char * server,
 113                                   const char * share, const char * workgroup, const char * user)
 114 {
 115         struct smbc_server_cache * srv = NULL;
 116
 117         /* Search the cache lines */
 118         for (srv=((struct smbc_server_cache *)context->server_cache);srv;srv=srv->next) {
 119
 120                 if (strcmp(server,srv->server_name)  == 0 &&
 121                     strcmp(workgroup,srv->workgroup) == 0 &&
 122                     strcmp(user, srv->username)  == 0) {
 123
 124                         /* If the share name matches, we're cool */
 125                         if (strcmp(share, srv->share_name) == 0) {
 126                                 return srv->server;
 127                         }
 128
 129                         /*
 130                          * We only return an empty share name or the attribute
 131                          * server on an exact match (which would have been
 132                          * caught above).
 133                          */
 134                         if (*share == '\0' || strcmp(share, "*IPC$") == 0)
 135                                 continue;
 136
 137                         /*
 138                          * Never return an empty share name or the attribute
 139                          * server if it wasn't what was requested.
 140                          */
 141                         if (*srv->share_name == '\0' ||
 142                             strcmp(srv->share_name, "*IPC$") == 0)
 143                                 continue;
 144
 145                         /*
 146                          * If we're only allowing one share per server, then
 147                          * a connection to the server (other than the
 148                          * attribute server connection) is cool.
 149                          */
 150                         if (context->options.one_share_per_server) {
 151                                 /*
 152                                  * The currently connected share name
 153                                  * doesn't match the requested share, so
 154                                  * disconnect from the current share.
 155                                  */
 156                                 if (! cli_tdis(srv->server->cli)) {
 157                                         /* Sigh. Couldn't disconnect. */
 158                                         cli_shutdown(srv->server->cli);
 159                                         srv->server->cli = NULL;
 160                                         context->callbacks.remove_cached_srv_fn(context, srv->server);
 161                                         continue;
 162                                 }
 163
 164                                 /*
 165                                  * Save the new share name.  We've
 166                                  * disconnected from the old share, and are
 167                                  * about to connect to the new one.
 168                                  */
 169                                 SAFE_FREE(srv->share_name);
 170                                 srv->share_name = SMB_STRDUP(share);
 171                                 if (!srv->share_name) {
 172                                         /* Out of memory. */
 173                                         cli_shutdown(srv->server->cli);
 174                                         srv->server->cli = NULL;
 175                                         context->callbacks.remove_cached_srv_fn(context, srv->server);
 176                                         continue;
 177                                 }
 178
 179
 180                                 return srv->server;
 181                         }
 182                 }
 183         }
 184
 185         return NULL;
 186 }
 187
 188
 189 /*
 190  * Search the server cache for a server and remove it
 191  * returns 0 on success
 192  * This function is only used if the external cache is not enabled
 193  */
 194 static int smbc_remove_cached_server(SMBCCTX * context, SMBCSRV * server)
 195 {
 196         struct smbc_server_cache * srv = NULL;
 197
 198         for (srv=((struct smbc_server_cache *)context->server_cache);srv;srv=srv->next) {
 199                 if (server == srv->server) {
 200
 201                         /* remove this sucker */
 202                         DLIST_REMOVE(context->server_cache, srv);
 203                         SAFE_FREE(srv->server_name);
 204                         SAFE_FREE(srv->share_name);
 205                         SAFE_FREE(srv->workgroup);
 206                         SAFE_FREE(srv->username);
 207                         SAFE_FREE(srv);
 208                         return 0;
 209                 }
 210         }
 211         /* server not found */
 212         return 1;
 213 }
 214
 215
 216 /*
 217  * Try to remove all the servers in cache
 218  * returns 1 on failure and 0 if all servers could be removed.
 219  */
 220 static int smbc_purge_cached(SMBCCTX * context)
 221 {
 222         struct smbc_server_cache * srv;
 223         struct smbc_server_cache * next;
 224         int could_not_purge_all = 0;
 225
 226         for (srv = ((struct smbc_server_cache *) context->server_cache),
 227                  next = (srv ? srv->next :NULL);
 228              srv;
 229              srv = next, next = (srv ? srv->next : NULL)) {
 230
 231                 if (smbc_remove_unused_server(context, srv->server)) {
 232                         /* could not be removed */
 233                         could_not_purge_all = 1;
 234                 }
 235         }
 236         return could_not_purge_all;
 237 }
 238
 239
 240
 241 /*
 242  * This functions initializes all server-cache related functions
 243  * to the default (internal) system.
 244  *
 245  * We use this to make the rest of the cache system static.
 246  */
 247
 248 int smbc_default_cache_functions(SMBCCTX * context)
 249 {
 250         context->callbacks.add_cached_srv_fn    = smbc_add_cached_server;
 251         context->callbacks.get_cached_srv_fn    = smbc_get_cached_server;
 252         context->callbacks.remove_cached_srv_fn = smbc_remove_cached_server;
 253         context->callbacks.purge_cached_fn      = smbc_purge_cached;
 254
 255         return 0;
 256 }