source/smbd/conn.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Manage connections_struct structures
   4    Copyright (C) Andrew Tridgell 1998
   5    Copyright (C) Alexander Bokovoy 2002
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 /* The connections bitmap is expanded in increments of BITMAP_BLOCK_SZ. The
  24  * maximum size of the bitmap is the largest positive integer, but you will hit
  25  * the "max connections" limit, looong before that.
  26  */
  27 #define BITMAP_BLOCK_SZ 128
  28
  29 static connection_struct *Connections;
  30
  31 /* number of open connections */
  32 static struct bitmap *bmap;
  33 static int num_open;
  34
  35 /****************************************************************************
  36 init the conn structures
  37 ****************************************************************************/
  38 void conn_init(void)
  39 {
  40         bmap = bitmap_allocate(BITMAP_BLOCK_SZ);
  41 }
  42
  43 /****************************************************************************
  44 return the number of open connections
  45 ****************************************************************************/
  46 int conn_num_open(void)
  47 {
  48         return num_open;
  49 }
  50
  51
  52 /****************************************************************************
  53 check if a snum is in use
  54 ****************************************************************************/
  55 bool conn_snum_used(int snum)
  56 {
  57         connection_struct *conn;
  58         for (conn=Connections;conn;conn=conn->next) {
  59                 if (conn->params->service == snum) {
  60                         return(True);
  61                 }
  62         }
  63         return(False);
  64 }
  65
  66 /****************************************************************************
  67  Find a conn given a cnum.
  68 ****************************************************************************/
  69
  70 connection_struct *conn_find(unsigned cnum)
  71 {
  72         int count=0;
  73         connection_struct *conn;
  74
  75         for (conn=Connections;conn;conn=conn->next,count++) {
  76                 if (conn->cnum == cnum) {
  77                         if (count > 10) {
  78                                 DLIST_PROMOTE(Connections, conn);
  79                         }
  80                         return conn;
  81                 }
  82         }
  83
  84         return NULL;
  85 }
  86
  87 /****************************************************************************
  88   find first available connection slot, starting from a random position.
  89 The randomisation stops problems with the server dieing and clients
  90 thinking the server is still available.
  91 ****************************************************************************/
  92 connection_struct *conn_new(void)
  93 {
  94         connection_struct *conn;
  95         int i;
  96         int find_offset = 1;
  97
  98 find_again:
  99         i = bitmap_find(bmap, find_offset);
 100
 101         if (i == -1) {
 102                 /* Expand the connections bitmap. */
 103                 int             oldsz = bmap->n;
 104                 int             newsz = bmap->n + BITMAP_BLOCK_SZ;
 105                 struct bitmap * nbmap;
 106
 107                 if (newsz <= oldsz) {
 108                         /* Integer wrap. */
 109                         DEBUG(0,("ERROR! Out of connection structures\n"));
 110                         return NULL;
 111                 }
 112
 113                 DEBUG(4,("resizing connections bitmap from %d to %d\n",
 114                         oldsz, newsz));
 115
 116                 nbmap = bitmap_allocate(newsz);
 117                 if (!nbmap) {
 118                         DEBUG(0,("ERROR! malloc fail.\n"));
 119                         return NULL;
 120                 }
 121
 122                 bitmap_copy(nbmap, bmap);
 123                 bitmap_free(bmap);
 124
 125                 bmap = nbmap;
 126                 find_offset = oldsz; /* Start next search in the new portion. */
 127
 128                 goto find_again;
 129         }
 130
 131         /* The bitmap position is used below as the connection number
 132          * conn->cnum). This ends up as the TID field in the SMB header,
 133          * which is limited to 16 bits (we skip 0xffff which is the
 134          * NULL TID).
 135          */
 136         if (i > 65534) {
 137                 DEBUG(0, ("Maximum connection limit reached\n"));
 138                 return NULL;
 139         }
 140
 141         if (!(conn=TALLOC_ZERO_P(NULL, connection_struct)) ||
 142             !(conn->params = TALLOC_P(conn, struct share_params))) {
 143                 DEBUG(0,("TALLOC_ZERO() failed!\n"));
 144                 TALLOC_FREE(conn);
 145                 return NULL;
 146         }
 147         conn->cnum = i;
 148
 149         bitmap_set(bmap, i);
 150
 151         num_open++;
 152
 153         string_set(&conn->dirpath,"");
 154         string_set(&conn->connectpath,"");
 155         string_set(&conn->origpath,"");
 156
 157         DLIST_ADD(Connections, conn);
 158
 159         return conn;
 160 }
 161
 162 /****************************************************************************
 163  Close all conn structures.
 164 return true if any were closed
 165 ****************************************************************************/
 166 bool conn_close_all(void)
 167 {
 168         connection_struct *conn, *next;
 169         bool ret = false;
 170         for (conn=Connections;conn;conn=next) {
 171                 next=conn->next;
 172                 set_current_service(conn, 0, True);
 173                 close_cnum(conn, conn->vuid);
 174                 ret = true;
 175         }
 176         return ret;
 177 }
 178
 179 /****************************************************************************
 180  Idle inactive connections.
 181 ****************************************************************************/
 182
 183 bool conn_idle_all(time_t t)
 184 {
 185         int deadtime = lp_deadtime()*60;
 186         pipes_struct *plist = NULL;
 187         connection_struct *conn;
 188
 189         if (deadtime <= 0)
 190                 deadtime = DEFAULT_SMBD_TIMEOUT;
 191
 192         for (conn=Connections;conn;conn=conn->next) {
 193
 194                 time_t age = t - conn->lastused;
 195
 196                 /* Update if connection wasn't idle. */
 197                 if (conn->lastused != conn->lastused_count) {
 198                         conn->lastused = t;
 199                         conn->lastused_count = t;
 200                 }
 201
 202                 /* close dirptrs on connections that are idle */
 203                 if (age > DPTR_IDLE_TIMEOUT) {
 204                         dptr_idlecnum(conn);
 205                 }
 206
 207                 if (conn->num_files_open > 0 || age < deadtime) {
 208                         return False;
 209                 }
 210         }
 211
 212         /*
 213          * Check all pipes for any open handles. We cannot
 214          * idle with a handle open.
 215          */
 216
 217         for (plist = get_first_internal_pipe(); plist;
 218              plist = get_next_internal_pipe(plist)) {
 219                 if (plist->pipe_handles && plist->pipe_handles->count) {
 220                         return False;
 221                 }
 222         }
 223
 224         return True;
 225 }
 226
 227 /****************************************************************************
 228  Clear a vuid out of the validity cache, and as the 'owner' of a connection.
 229 ****************************************************************************/
 230
 231 void conn_clear_vuid_caches(uint16_t vuid)
 232 {
 233         connection_struct *conn;
 234
 235         for (conn=Connections;conn;conn=conn->next) {
 236                 if (conn->vuid == vuid) {
 237                         conn->vuid = UID_FIELD_INVALID;
 238                 }
 239                 conn_clear_vuid_cache(conn, vuid);
 240         }
 241 }
 242
 243 /****************************************************************************
 244  Free a conn structure - internal part.
 245 ****************************************************************************/
 246
 247 void conn_free_internal(connection_struct *conn)
 248 {
 249         vfs_handle_struct *handle = NULL, *thandle = NULL;
 250         struct trans_state *state = NULL;
 251
 252         /* Free vfs_connection_struct */
 253         handle = conn->vfs_handles;
 254         while(handle) {
 255                 DLIST_REMOVE(conn->vfs_handles, handle);
 256                 thandle = handle->next;
 257                 if (handle->free_data)
 258                         handle->free_data(&handle->data);
 259                 handle = thandle;
 260         }
 261
 262         /* Free any pending transactions stored on this conn. */
 263         for (state = conn->pending_trans; state; state = state->next) {
 264                 /* state->setup is a talloc child of state. */
 265                 SAFE_FREE(state->param);
 266                 SAFE_FREE(state->data);
 267         }
 268
 269         free_namearray(conn->veto_list);
 270         free_namearray(conn->hide_list);
 271         free_namearray(conn->veto_oplock_list);
 272         free_namearray(conn->aio_write_behind_list);
 273
 274         string_free(&conn->dirpath);
 275         string_free(&conn->connectpath);
 276         string_free(&conn->origpath);
 277
 278         ZERO_STRUCTP(conn);
 279         talloc_destroy(conn);
 280 }
 281
 282 /****************************************************************************
 283  Free a conn structure.
 284 ****************************************************************************/
 285
 286 void conn_free(connection_struct *conn)
 287 {
 288         DLIST_REMOVE(Connections, conn);
 289
 290         bitmap_clear(bmap, conn->cnum);
 291
 292         SMB_ASSERT(num_open > 0);
 293         num_open--;
 294
 295         conn_free_internal(conn);
 296 }
 297
 298 /****************************************************************************
 299 receive a smbcontrol message to forcibly unmount a share
 300 the message contains just a share name and all instances of that
 301 share are unmounted
 302 the special sharename '*' forces unmount of all shares
 303 ****************************************************************************/
 304 void msg_force_tdis(struct messaging_context *msg,
 305                     void *private_data,
 306                     uint32_t msg_type,
 307                     struct server_id server_id,
 308                     DATA_BLOB *data)
 309 {
 310         connection_struct *conn, *next;
 311         fstring sharename;
 312
 313         fstrcpy(sharename, (const char *)data->data);
 314
 315         if (strcmp(sharename, "*") == 0) {
 316                 DEBUG(1,("Forcing close of all shares\n"));
 317                 conn_close_all();
 318                 return;
 319         }
 320
 321         for (conn=Connections;conn;conn=next) {
 322                 next=conn->next;
 323                 if (strequal(lp_servicename(SNUM(conn)), sharename)) {
 324                         DEBUG(1,("Forcing close of share %s cnum=%d\n",
 325                                  sharename, conn->cnum));
 326                         close_cnum(conn, (uint16)-1);
 327                 }
 328         }
 329 }