source3/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                 DEBUG(0,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  59                                 name, tdb_errorstr(tdb) ));
  60                 return (False);
  61         }
  62
  63         return(True);
  64 }
  65
  66 struct count_stat {
  67         pid_t mypid;
  68         int curr_connections;
  69         char *name;
  70         BOOL Clear;
  71 };
  72
  73 /****************************************************************************
  74  Count the entries belonging to a service in the connection db.
  75 ****************************************************************************/
  76
  77 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  78 {
  79         struct connections_data crec;
  80         struct count_stat *cs = (struct count_stat *)udp;
  81
  82         if (dbuf.dsize != sizeof(crec))
  83                 return 0;
  84
  85         memcpy(&crec, dbuf.dptr, sizeof(crec));
  86
  87     if (crec.cnum == -1)
  88                 return 0;
  89
  90         /* If the pid was not found delete the entry from connections.tdb */
  91
  92         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
  93                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
  94                         (unsigned int)crec.pid, crec.cnum, crec.name));
  95                 if (tdb_delete(the_tdb, kbuf) != 0)
  96                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
  97                 return 0;
  98         }
  99
 100         if (strequal(crec.name, cs->name))
 101                 cs->curr_connections++;
 102
 103         return 0;
 104 }
 105
 106 /****************************************************************************
 107  Claim an entry in the connections database.
 108 ****************************************************************************/
 109
 110 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear)
 111 {
 112         struct connections_key key;
 113         struct connections_data crec;
 114         TDB_DATA kbuf, dbuf;
 115
 116         if (!tdb) {
 117                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 118                                O_RDWR | O_CREAT, 0644);
 119         }
 120         if (!tdb)
 121                 return False;
 122
 123         /*
 124          * Enforce the max connections parameter.
 125          */
 126
 127         if (max_connections > 0) {
 128                 struct count_stat cs;
 129
 130                 cs.mypid = sys_getpid();
 131                 cs.curr_connections = 0;
 132                 cs.name = lp_servicename(SNUM(conn));
 133                 cs.Clear = Clear;
 134
 135                 /*
 136                  * This has a race condition, but locking the chain before hand is worse
 137                  * as it leads to deadlock.
 138                  */
 139
 140                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 141                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 142                                 tdb_errorstr(tdb) ));
 143                         return False;
 144                 }
 145
 146                 if (cs.curr_connections >= max_connections) {
 147                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 148                                 max_connections, name ));
 149                         return False;
 150                 }
 151         }
 152
 153         DEBUG(5,("claiming %s %d\n",name,max_connections));
 154
 155         ZERO_STRUCT(key);
 156         key.pid = sys_getpid();
 157         key.cnum = conn?conn->cnum:-1;
 158         fstrcpy(key.name, name);
 159
 160         kbuf.dptr = (char *)&key;
 161         kbuf.dsize = sizeof(key);
 162
 163         /* fill in the crec */
 164         ZERO_STRUCT(crec);
 165         crec.magic = 0x280267;
 166         crec.pid = sys_getpid();
 167         crec.cnum = conn?conn->cnum:-1;
 168         if (conn) {
 169                 crec.uid = conn->uid;
 170                 crec.gid = conn->gid;
 171                 StrnCpy(crec.name,
 172                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 173         }
 174         crec.start = time(NULL);
 175
 176         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 177         StrnCpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 178
 179         dbuf.dptr = (char *)&crec;
 180         dbuf.dsize = sizeof(crec);
 181
 182         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 183                 DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
 184                         tdb_errorstr(tdb) ));
 185                 return False;
 186         }
 187
 188         return True;
 189 }