source3/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 extern fstring remote_machine;
  24 static TDB_CONTEXT *tdb;
  25
  26 /****************************************************************************
  27  Return the connection tdb context (used for message send all).
  28 ****************************************************************************/
  29
  30 TDB_CONTEXT *conn_tdb_ctx(void)
  31 {
  32         if (!tdb) {
  33                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
  34                                O_RDWR | O_CREAT, 0644);
  35         }
  36
  37         return tdb;
  38 }
  39
  40 /****************************************************************************
  41  Delete a connection record.
  42 ****************************************************************************/
  43
  44 BOOL yield_connection(connection_struct *conn,char *name)
  45 {
  46         struct connections_key key;
  47         TDB_DATA kbuf;
  48
  49         if (!tdb) return False;
  50
  51         DEBUG(3,("Yielding connection to %s\n",name));
  52
  53         ZERO_STRUCT(key);
  54         key.pid = sys_getpid();
  55         key.cnum = conn?conn->cnum:-1;
  56         fstrcpy(key.name, name);
  57
  58         kbuf.dptr = (char *)&key;
  59         kbuf.dsize = sizeof(key);
  60
  61         if (tdb_delete(tdb, kbuf) != 0) {
  62                 int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
  63                 DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  64                         name, tdb_errorstr(tdb) ));
  65                 return (False);
  66         }
  67
  68         return(True);
  69 }
  70
  71 struct count_stat {
  72         pid_t mypid;
  73         int curr_connections;
  74         char *name;
  75         BOOL Clear;
  76 };
  77
  78 /****************************************************************************
  79  Count the entries belonging to a service in the connection db.
  80 ****************************************************************************/
  81
  82 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  83 {
  84         struct connections_data crec;
  85         struct count_stat *cs = (struct count_stat *)udp;
  86
  87         if (dbuf.dsize != sizeof(crec))
  88                 return 0;
  89
  90         memcpy(&crec, dbuf.dptr, sizeof(crec));
  91
  92     if (crec.cnum == -1)
  93                 return 0;
  94
  95         /* If the pid was not found delete the entry from connections.tdb */
  96
  97         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
  98                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
  99                         (unsigned int)crec.pid, crec.cnum, crec.name));
 100                 if (tdb_delete(the_tdb, kbuf) != 0)
 101                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
 102                 return 0;
 103         }
 104
 105         if (strequal(crec.name, cs->name))
 106                 cs->curr_connections++;
 107
 108         return 0;
 109 }
 110
 111 /****************************************************************************
 112  Claim an entry in the connections database.
 113 ****************************************************************************/
 114
 115 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear)
 116 {
 117         struct connections_key key;
 118         struct connections_data crec;
 119         TDB_DATA kbuf, dbuf;
 120
 121         if (!tdb) {
 122                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 123                                O_RDWR | O_CREAT, 0644);
 124         }
 125         if (!tdb)
 126                 return False;
 127
 128         /*
 129          * Enforce the max connections parameter.
 130          */
 131
 132         if (max_connections > 0) {
 133                 struct count_stat cs;
 134
 135                 cs.mypid = sys_getpid();
 136                 cs.curr_connections = 0;
 137                 cs.name = lp_servicename(SNUM(conn));
 138                 cs.Clear = Clear;
 139
 140                 /*
 141                  * This has a race condition, but locking the chain before hand is worse
 142                  * as it leads to deadlock.
 143                  */
 144
 145                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 146                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 147                                 tdb_errorstr(tdb) ));
 148                         return False;
 149                 }
 150
 151                 if (cs.curr_connections >= max_connections) {
 152                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 153                                 max_connections, name ));
 154                         return False;
 155                 }
 156         }
 157
 158         DEBUG(5,("claiming %s %d\n",name,max_connections));
 159
 160         ZERO_STRUCT(key);
 161         key.pid = sys_getpid();
 162         key.cnum = conn?conn->cnum:-1;
 163         fstrcpy(key.name, name);
 164
 165         kbuf.dptr = (char *)&key;
 166         kbuf.dsize = sizeof(key);
 167
 168         /* fill in the crec */
 169         ZERO_STRUCT(crec);
 170         crec.magic = 0x280267;
 171         crec.pid = sys_getpid();
 172         crec.cnum = conn?conn->cnum:-1;
 173         if (conn) {
 174                 crec.uid = conn->uid;
 175                 crec.gid = conn->gid;
 176                 StrnCpy(crec.name,
 177                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 178         }
 179         crec.start = time(NULL);
 180
 181         StrnCpy(crec.machine,remote_machine,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 }