source/smbd/connection.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    connection claim routines
   5    Copyright (C) Andrew Tridgell 1998
   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 2 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, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 extern fstring remote_machine;
  25 static TDB_CONTEXT *tdb;
  26
  27 /****************************************************************************
  28  Return the connection tdb context (used for message send all).
  29 ****************************************************************************/
  30
  31 TDB_CONTEXT *conn_tdb_ctx(void)
  32 {
  33         return tdb;
  34 }
  35
  36 /****************************************************************************
  37  Delete a connection record.
  38 ****************************************************************************/
  39
  40 BOOL yield_connection(connection_struct *conn,char *name,int max_connections)
  41 {
  42         struct connections_key key;
  43         TDB_DATA kbuf;
  44
  45         if (!tdb) return False;
  46
  47         DEBUG(3,("Yielding connection to %s\n",name));
  48
  49         ZERO_STRUCT(key);
  50         key.pid = sys_getpid();
  51         key.cnum = conn?conn->cnum:-1;
  52         fstrcpy(key.name, name);
  53
  54         kbuf.dptr = (char *)&key;
  55         kbuf.dsize = sizeof(key);
  56
  57         if (tdb_delete(tdb, kbuf) != 0) {
  58                 int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
  59                 DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  60                         name, tdb_errorstr(tdb) ));
  61                 return (False);
  62         }
  63
  64         return(True);
  65 }
  66
  67 struct count_stat {
  68         pid_t mypid;
  69         int curr_connections;
  70         char *name;
  71         BOOL Clear;
  72 };
  73
  74 /****************************************************************************
  75  Count the entries belonging to a service in the connection db.
  76 ****************************************************************************/
  77
  78 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  79 {
  80         struct connections_data crec;
  81         struct count_stat *cs = (struct count_stat *)udp;
  82
  83         if (dbuf.dsize != sizeof(crec))
  84                 return 0;
  85
  86         memcpy(&crec, dbuf.dptr, sizeof(crec));
  87
  88     if (crec.cnum == -1)
  89                 return 0;
  90
  91         /* If the pid was not found delete the entry from connections.tdb */
  92
  93         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
  94                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
  95                         (unsigned int)crec.pid, crec.cnum, crec.name));
  96                 if (tdb_delete(the_tdb, kbuf) != 0)
  97                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
  98                 return 0;
  99         }
 100
 101         if (strequal(crec.name, cs->name))
 102                 cs->curr_connections++;
 103
 104         return 0;
 105 }
 106
 107 /****************************************************************************
 108  Claim an entry in the connections database.
 109 ****************************************************************************/
 110
 111 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear)
 112 {
 113         struct connections_key key;
 114         struct connections_data crec;
 115         TDB_DATA kbuf, dbuf;
 116
 117         if (!tdb) {
 118                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 119                                O_RDWR | O_CREAT, 0644);
 120         }
 121         if (!tdb)
 122                 return False;
 123
 124         /*
 125          * Enforce the max connections parameter.
 126          */
 127
 128         if (max_connections > 0) {
 129                 struct count_stat cs;
 130
 131                 cs.mypid = sys_getpid();
 132                 cs.curr_connections = 0;
 133                 cs.name = lp_servicename(SNUM(conn));
 134                 cs.Clear = Clear;
 135
 136                 /*
 137                  * This has a race condition, but locking the chain before hand is worse
 138                  * as it leads to deadlock.
 139                  */
 140
 141                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 142                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 143                                 tdb_errorstr(tdb) ));
 144                         return False;
 145                 }
 146
 147                 if (cs.curr_connections >= max_connections) {
 148                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 149                                 max_connections, name ));
 150                         return False;
 151                 }
 152         }
 153
 154         DEBUG(5,("claiming %s %d\n",name,max_connections));
 155
 156         ZERO_STRUCT(key);
 157         key.pid = sys_getpid();
 158         key.cnum = conn?conn->cnum:-1;
 159         fstrcpy(key.name, name);
 160
 161         kbuf.dptr = (char *)&key;
 162         kbuf.dsize = sizeof(key);
 163
 164         /* fill in the crec */
 165         ZERO_STRUCT(crec);
 166         crec.magic = 0x280267;
 167         crec.pid = sys_getpid();
 168         crec.cnum = conn?conn->cnum:-1;
 169         if (conn) {
 170                 crec.uid = conn->uid;
 171                 crec.gid = conn->gid;
 172                 StrnCpy(crec.name,
 173                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 174         }
 175         crec.start = time(NULL);
 176
 177         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 178         StrnCpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 179
 180         dbuf.dptr = (char *)&crec;
 181         dbuf.dsize = sizeof(crec);
 182
 183         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 184                 DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
 185                         tdb_errorstr(tdb) ));
 186                 return False;
 187         }
 188
 189         return True;
 190 }