source/smbd/connection.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    connection claim routines
   4    Copyright (C) Andrew Tridgell 1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 static TDB_CONTEXT *tdb;
  24
  25 /****************************************************************************
  26  Return the connection tdb context (used for message send all).
  27 ****************************************************************************/
  28
  29 TDB_CONTEXT *conn_tdb_ctx(void)
  30 {
  31         if (!tdb)
  32                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
  33                                O_RDWR | O_CREAT, 0644);
  34
  35         return tdb;
  36 }
  37
  38 /****************************************************************************
  39  Delete a connection record.
  40 ****************************************************************************/
  41
  42 BOOL yield_connection(connection_struct *conn,char *name)
  43 {
  44         struct connections_key key;
  45         TDB_DATA kbuf;
  46
  47         if (!tdb)
  48                 return False;
  49
  50         DEBUG(3,("Yielding connection to %s\n",name));
  51
  52         ZERO_STRUCT(key);
  53         key.pid = sys_getpid();
  54         key.cnum = conn?conn->cnum:-1;
  55         fstrcpy(key.name, name);
  56
  57         kbuf.dptr = (char *)&key;
  58         kbuf.dsize = sizeof(key);
  59
  60         if (tdb_delete(tdb, kbuf) != 0) {
  61                 int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
  62                 DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  63                         name, tdb_errorstr(tdb) ));
  64                 return (False);
  65         }
  66
  67         return(True);
  68 }
  69
  70 struct count_stat {
  71         pid_t mypid;
  72         int curr_connections;
  73         char *name;
  74         BOOL Clear;
  75 };
  76
  77 /****************************************************************************
  78  Count the entries belonging to a service in the connection db.
  79 ****************************************************************************/
  80
  81 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  82 {
  83         struct connections_data crec;
  84         struct count_stat *cs = (struct count_stat *)udp;
  85
  86         if (dbuf.dsize != sizeof(crec))
  87                 return 0;
  88
  89         memcpy(&crec, dbuf.dptr, sizeof(crec));
  90
  91     if (crec.cnum == -1)
  92                 return 0;
  93
  94         /* If the pid was not found delete the entry from connections.tdb */
  95
  96         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
  97                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
  98                         (unsigned int)crec.pid, crec.cnum, crec.name));
  99                 if (tdb_delete(the_tdb, kbuf) != 0)
 100                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
 101                 return 0;
 102         }
 103
 104         if (strequal(crec.name, cs->name))
 105                 cs->curr_connections++;
 106
 107         return 0;
 108 }
 109
 110 /****************************************************************************
 111  Claim an entry in the connections database.
 112 ****************************************************************************/
 113
 114 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear, uint32 msg_flags)
 115 {
 116         struct connections_key key;
 117         struct connections_data crec;
 118         TDB_DATA kbuf, dbuf;
 119
 120         if (!tdb)
 121                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 122                                O_RDWR | O_CREAT, 0644);
 123
 124         if (!tdb)
 125                 return False;
 126
 127         /*
 128          * Enforce the max connections parameter.
 129          */
 130
 131         if (max_connections > 0) {
 132                 struct count_stat cs;
 133
 134                 cs.mypid = sys_getpid();
 135                 cs.curr_connections = 0;
 136                 cs.name = lp_servicename(SNUM(conn));
 137                 cs.Clear = Clear;
 138
 139                 /*
 140                  * This has a race condition, but locking the chain before hand is worse
 141                  * as it leads to deadlock.
 142                  */
 143
 144                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 145                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 146                                 tdb_errorstr(tdb) ));
 147                         return False;
 148                 }
 149
 150                 if (cs.curr_connections >= max_connections) {
 151                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 152                                 max_connections, name ));
 153                         return False;
 154                 }
 155         }
 156
 157         DEBUG(5,("claiming %s %d\n",name,max_connections));
 158
 159         ZERO_STRUCT(key);
 160         key.pid = sys_getpid();
 161         key.cnum = conn?conn->cnum:-1;
 162         fstrcpy(key.name, name);
 163
 164         kbuf.dptr = (char *)&key;
 165         kbuf.dsize = sizeof(key);
 166
 167         /* fill in the crec */
 168         ZERO_STRUCT(crec);
 169         crec.magic = 0x280267;
 170         crec.pid = sys_getpid();
 171         crec.cnum = conn?conn->cnum:-1;
 172         if (conn) {
 173                 crec.uid = conn->uid;
 174                 crec.gid = conn->gid;
 175                 StrnCpy(crec.name,
 176                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 177         }
 178         crec.start = time(NULL);
 179         crec.bcast_msg_flags = msg_flags;
 180
 181         StrnCpy(crec.machine,get_remote_machine_name(),sizeof(crec.machine)-1);
 182         StrnCpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 183
 184         dbuf.dptr = (char *)&crec;
 185         dbuf.dsize = sizeof(crec);
 186
 187         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 188                 DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
 189                         tdb_errorstr(tdb) ));
 190                 return False;
 191         }
 192
 193         return True;
 194 }