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