source/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, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25
  26 #include "include/libsmbclient.h"
  27 #include "../include/libsmb_internal.h"
  28
  29 int smbc_default_cache_functions(SMBCCTX * context);
  30
  31 /*
  32  * Structure we use if internal caching mechanism is used
  33  * nothing fancy here.
  34  */
  35 struct smbc_server_cache {
  36         char *server_name;
  37         char *share_name;
  38         char *workgroup;
  39         char *username;
  40         SMBCSRV *server;
  41
  42         struct smbc_server_cache *next, *prev;
  43 };
  44
  45
  46
  47 /*
  48  * Add a new connection to the server cache.
  49  * This function is only used if the external cache is not enabled
  50  */
  51 static int smbc_add_cached_server(SMBCCTX * context, SMBCSRV * newsrv,
  52                                   const char * server, const char * share,
  53                                   const char * workgroup, const char * username)
  54 {
  55         struct smbc_server_cache * srvcache = NULL;
  56
  57         if (!(srvcache = SMB_MALLOC_P(struct smbc_server_cache))) {
  58                 errno = ENOMEM;
  59                 DEBUG(3, ("Not enough space for server cache allocation\n"));
  60                 return 1;
  61         }
  62
  63         ZERO_STRUCTP(srvcache);
  64
  65         srvcache->server = newsrv;
  66
  67         srvcache->server_name = SMB_STRDUP(server);
  68         if (!srvcache->server_name) {
  69                 errno = ENOMEM;
  70                 goto failed;
  71         }
  72
  73         srvcache->share_name = SMB_STRDUP(share);
  74         if (!srvcache->share_name) {
  75                 errno = ENOMEM;
  76                 goto failed;
  77         }
  78
  79         srvcache->workgroup = SMB_STRDUP(workgroup);
  80         if (!srvcache->workgroup) {
  81                 errno = ENOMEM;
  82                 goto failed;
  83         }
  84
  85         srvcache->username = SMB_STRDUP(username);
  86         if (!srvcache->username) {
  87                 errno = ENOMEM;
  88                 goto failed;
  89         }
  90
  91         DLIST_ADD((context->server_cache), srvcache);
  92         return 0;
  93
  94  failed:
  95         SAFE_FREE(srvcache->server_name);
  96         SAFE_FREE(srvcache->share_name);
  97         SAFE_FREE(srvcache->workgroup);
  98         SAFE_FREE(srvcache->username);
  99         SAFE_FREE(srvcache);
 100
 101         return 1;
 102 }
 103
 104
 105
 106 /*
 107  * Search the server cache for a server
 108  * returns server handle on success, NULL on error (not found)
 109  * This function is only used if the external cache is not enabled
 110  */
 111 static SMBCSRV * smbc_get_cached_server(SMBCCTX * context, const char * server,
 112                                   const char * share, const char * workgroup, const char * user)
 113 {
 114         struct smbc_server_cache * srv = NULL;
 115
 116         /* Search the cache lines */
 117         for (srv=((struct smbc_server_cache *)context->server_cache);srv;srv=srv->next) {
 118
 119                 if (strcmp(server,srv->server_name)  == 0 &&
 120                     strcmp(workgroup,srv->workgroup) == 0 &&
 121                     strcmp(user, srv->username)  == 0) {
 122
 123                         /* If the share name matches, we're cool */
 124                         if (strcmp(share, srv->share_name) == 0) {
 125                                 return srv->server;
 126                         }
 127
 128                         /*
 129                          * We only return an empty share name or the attribute
 130                          * server on an exact match (which would have been
 131                          * caught above).
 132                          */
 133                         if (*share == '\0' || strcmp(share, "*IPC$") == 0)
 134                                 continue;
 135
 136                         /*
 137                          * Never return an empty share name or the attribute
 138                          * server if it wasn't what was requested.
 139                          */
 140                         if (*srv->share_name == '\0' ||
 141                             strcmp(srv->share_name, "*IPC$") == 0)
 142                                 continue;
 143
 144                         /*
 145                          * If we're only allowing one share per server, then
 146                          * a connection to the server (other than the
 147                          * attribute server connection) is cool.
 148                          */
 149                         if (context->options.one_share_per_server) {
 150                                 /*
 151                                  * The currently connected share name
 152                                  * doesn't match the requested share, so
 153                                  * disconnect from the current share.
 154                                  */
 155                                 if (! cli_tdis(srv->server->cli)) {
 156                                         /* Sigh. Couldn't disconnect. */
 157                                         cli_shutdown(srv->server->cli);
 158                                         srv->server->cli = NULL;
 159                                         context->callbacks.remove_cached_srv_fn(context, srv->server);
 160                                         continue;
 161                                 }
 162
 163                                 /*
 164                                  * Save the new share name.  We've
 165                                  * disconnected from the old share, and are
 166                                  * about to connect to the new one.
 167                                  */
 168                                 SAFE_FREE(srv->share_name);
 169                                 srv->share_name = SMB_STRDUP(share);
 170                                 if (!srv->share_name) {
 171                                         /* Out of memory. */
 172                                         cli_shutdown(srv->server->cli);
 173                                         srv->server->cli = NULL;
 174                                         context->callbacks.remove_cached_srv_fn(context, srv->server);
 175                                         continue;
 176                                 }
 177
 178
 179                                 return srv->server;
 180                         }
 181                 }
 182         }
 183
 184         return NULL;
 185 }
 186
 187
 188 /*
 189  * Search the server cache for a server and remove it
 190  * returns 0 on success
 191  * This function is only used if the external cache is not enabled
 192  */
 193 static int smbc_remove_cached_server(SMBCCTX * context, SMBCSRV * server)
 194 {
 195         struct smbc_server_cache * srv = NULL;
 196
 197         for (srv=((struct smbc_server_cache *)context->server_cache);srv;srv=srv->next) {
 198                 if (server == srv->server) {
 199
 200                         /* remove this sucker */
 201                         DLIST_REMOVE(context->server_cache, srv);
 202                         SAFE_FREE(srv->server_name);
 203                         SAFE_FREE(srv->share_name);
 204                         SAFE_FREE(srv->workgroup);
 205                         SAFE_FREE(srv->username);
 206                         SAFE_FREE(srv);
 207                         return 0;
 208                 }
 209         }
 210         /* server not found */
 211         return 1;
 212 }
 213
 214
 215 /*
 216  * Try to remove all the servers in cache
 217  * returns 1 on failure and 0 if all servers could be removed.
 218  */
 219 static int smbc_purge_cached(SMBCCTX * context)
 220 {
 221         struct smbc_server_cache * srv;
 222         struct smbc_server_cache * next;
 223         int could_not_purge_all = 0;
 224
 225         for (srv = ((struct smbc_server_cache *) context->server_cache),
 226                  next = (srv ? srv->next :NULL);
 227              srv;
 228              srv = next, next = (srv ? srv->next : NULL)) {
 229
 230                 if (smbc_remove_unused_server(context, srv->server)) {
 231                         /* could not be removed */
 232                         could_not_purge_all = 1;
 233                 }
 234         }
 235         return could_not_purge_all;
 236 }
 237
 238
 239
 240 /*
 241  * This functions initializes all server-cache related functions
 242  * to the default (internal) system.
 243  *
 244  * We use this to make the rest of the cache system static.
 245  */
 246
 247 int smbc_default_cache_functions(SMBCCTX * context)
 248 {
 249         context->callbacks.add_cached_srv_fn    = smbc_add_cached_server;
 250         context->callbacks.get_cached_srv_fn    = smbc_get_cached_server;
 251         context->callbacks.remove_cached_srv_fn = smbc_remove_cached_server;
 252         context->callbacks.purge_cached_fn      = smbc_purge_cached;
 253
 254         return 0;
 255 }