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         conn->force_group_gid = (gid_t)-1;
 149
 150         bitmap_set(bmap, i);
 151
 152         num_open++;
 153
 154         string_set(&conn->dirpath,"");
 155         string_set(&conn->connectpath,"");
 156         string_set(&conn->origpath,"");
 157
 158         DLIST_ADD(Connections, conn);
 159
 160         return conn;
 161 }
 162
 163 /****************************************************************************
 164  Close all conn structures.
 165 return true if any were closed
 166 ****************************************************************************/
 167 bool conn_close_all(void)
 168 {
 169         connection_struct *conn, *next;
 170         bool ret = false;
 171         for (conn=Connections;conn;conn=next) {
 172                 next=conn->next;
 173                 set_current_service(conn, 0, True);
 174                 close_cnum(conn, conn->vuid);
 175                 ret = true;
 176         }
 177         return ret;
 178 }
 179
 180 /****************************************************************************
 181  Idle inactive connections.
 182 ****************************************************************************/
 183
 184 bool conn_idle_all(time_t t)
 185 {
 186         int deadtime = lp_deadtime()*60;
 187         pipes_struct *plist = NULL;
 188         connection_struct *conn;
 189
 190         if (deadtime <= 0)
 191                 deadtime = DEFAULT_SMBD_TIMEOUT;
 192
 193         for (conn=Connections;conn;conn=conn->next) {
 194
 195                 time_t age = t - conn->lastused;
 196
 197                 /* Update if connection wasn't idle. */
 198                 if (conn->lastused != conn->lastused_count) {
 199                         conn->lastused = t;
 200                         conn->lastused_count = t;
 201                 }
 202
 203                 /* close dirptrs on connections that are idle */
 204                 if (age > DPTR_IDLE_TIMEOUT) {
 205                         dptr_idlecnum(conn);
 206                 }
 207
 208                 if (conn->num_files_open > 0 || age < deadtime) {
 209                         return False;
 210                 }
 211         }
 212
 213         /*
 214          * Check all pipes for any open handles. We cannot
 215          * idle with a handle open.
 216          */
 217
 218         for (plist = get_first_internal_pipe(); plist;
 219              plist = get_next_internal_pipe(plist)) {
 220                 if (plist->pipe_handles && plist->pipe_handles->count) {
 221                         return False;
 222                 }
 223         }
 224
 225         return True;
 226 }
 227
 228 /****************************************************************************
 229  Clear a vuid out of the validity cache, and as the 'owner' of a connection.
 230 ****************************************************************************/
 231
 232 void conn_clear_vuid_caches(uint16_t vuid)
 233 {
 234         connection_struct *conn;
 235
 236         for (conn=Connections;conn;conn=conn->next) {
 237                 if (conn->vuid == vuid) {
 238                         conn->vuid = UID_FIELD_INVALID;
 239                 }
 240                 conn_clear_vuid_cache(conn, vuid);
 241         }
 242 }
 243
 244 /****************************************************************************
 245  Free a conn structure - internal part.
 246 ****************************************************************************/
 247
 248 void conn_free_internal(connection_struct *conn)
 249 {
 250         vfs_handle_struct *handle = NULL, *thandle = NULL;
 251         struct trans_state *state = NULL;
 252
 253         /* Free vfs_connection_struct */
 254         handle = conn->vfs_handles;
 255         while(handle) {
 256                 thandle = handle->next;
 257                 DLIST_REMOVE(conn->vfs_handles, handle);
 258                 if (handle->free_data)
 259                         handle->free_data(&handle->data);
 260                 handle = thandle;
 261         }
 262
 263         /* Free any pending transactions stored on this conn. */
 264         for (state = conn->pending_trans; state; state = state->next) {
 265                 /* state->setup is a talloc child of state. */
 266                 SAFE_FREE(state->param);
 267                 SAFE_FREE(state->data);
 268         }
 269
 270         free_namearray(conn->veto_list);
 271         free_namearray(conn->hide_list);
 272         free_namearray(conn->veto_oplock_list);
 273         free_namearray(conn->aio_write_behind_list);
 274
 275         string_free(&conn->dirpath);
 276         string_free(&conn->connectpath);
 277         string_free(&conn->origpath);
 278
 279         ZERO_STRUCTP(conn);
 280         talloc_destroy(conn);
 281 }
 282
 283 /****************************************************************************
 284  Free a conn structure.
 285 ****************************************************************************/
 286
 287 void conn_free(connection_struct *conn)
 288 {
 289         DLIST_REMOVE(Connections, conn);
 290
 291         bitmap_clear(bmap, conn->cnum);
 292
 293         SMB_ASSERT(num_open > 0);
 294         num_open--;
 295
 296         conn_free_internal(conn);
 297 }
 298
 299 /****************************************************************************
 300 receive a smbcontrol message to forcibly unmount a share
 301 the message contains just a share name and all instances of that
 302 share are unmounted
 303 the special sharename '*' forces unmount of all shares
 304 ****************************************************************************/
 305 void msg_force_tdis(struct messaging_context *msg,
 306                     void *private_data,
 307                     uint32_t msg_type,
 308                     struct server_id server_id,
 309                     DATA_BLOB *data)
 310 {
 311         connection_struct *conn, *next;
 312         fstring sharename;
 313
 314         fstrcpy(sharename, (const char *)data->data);
 315
 316         if (strcmp(sharename, "*") == 0) {
 317                 DEBUG(1,("Forcing close of all shares\n"));
 318                 conn_close_all();
 319                 return;
 320         }
 321
 322         for (conn=Connections;conn;conn=next) {
 323                 next=conn->next;
 324                 if (strequal(lp_servicename(SNUM(conn)), sharename)) {
 325                         DEBUG(1,("Forcing close of share %s cnum=%d\n",
 326                                  sharename, conn->cnum));
 327                         close_cnum(conn, (uint16)-1);
 328                 }
 329         }
 330 }