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
  25 extern fstring remote_machine;
  26 static TDB_CONTEXT *tdb;
  27
  28 extern int DEBUGLEVEL;
  29
  30 /****************************************************************************
  31  Return the connection tdb context (used for message send all).
  32 ****************************************************************************/
  33
  34 TDB_CONTEXT *conn_tdb_ctx(void)
  35 {
  36         return tdb;
  37 }
  38
  39 /****************************************************************************
  40  Delete a connection record.
  41 ****************************************************************************/
  42
  43 BOOL yield_connection(connection_struct *conn,char *name,int max_connections)
  44 {
  45         struct connections_key key;
  46         TDB_DATA kbuf;
  47
  48         if (!tdb) 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                 DEBUG(0,("yield_connection: tdb_delete failed with error %s.\n", tdb_errorstr(tdb) ));
  62                 return (False);
  63         }
  64
  65         return(True);
  66 }
  67
  68 struct count_stat {
  69         pid_t mypid;
  70         int curr_connections;
  71         char *name;
  72         BOOL Clear;
  73 };
  74
  75 /****************************************************************************
  76  Count the entries belonging to a service in the connection db.
  77 ****************************************************************************/
  78
  79 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  80 {
  81         struct connections_data crec;
  82         struct count_stat *cs = (struct count_stat *)udp;
  83
  84         if (dbuf.dsize != sizeof(crec))
  85                 return 0;
  86
  87         memcpy(&crec, dbuf.dptr, sizeof(crec));
  88
  89     if (crec.cnum == -1)
  90                 return 0;
  91
  92         /* If the pid was not found delete the entry from connections.tdb */
  93
  94         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
  95                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
  96                         (unsigned int)crec.pid, crec.cnum, crec.name));
  97                 if (tdb_delete(the_tdb, kbuf) != 0)
  98                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
  99                 return 0;
 100         }
 101
 102         if (strequal(crec.name, cs->name))
 103                 cs->curr_connections++;
 104
 105         return 0;
 106 }
 107
 108 /****************************************************************************
 109  Claim an entry in the connections database.
 110 ****************************************************************************/
 111
 112 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear)
 113 {
 114         struct connections_key key;
 115         struct connections_data crec;
 116         TDB_DATA kbuf, dbuf, lockkey;
 117         BOOL rec_locked = False;
 118         BOOL ret = True;
 119
 120         if (!tdb) {
 121                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST,
 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                 lockkey.dptr = cs.name;
 140                 lockkey.dsize = strlen(cs.name)+1;
 141
 142                 /*
 143                  * Go through and count the connections with hash chain representing the service name
 144                  * locked. This is slow but removes race conditions. JRA.
 145                  */
 146
 147                 if (tdb_chainlock(tdb, lockkey)) {
 148                         DEBUG(0,("claim_connection: tdb_chainlock failed %s\n",
 149                                 tdb_errorstr(tdb) ));
 150                         return False;
 151                 }
 152
 153                 rec_locked = True;
 154
 155                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 156                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 157                                 tdb_errorstr(tdb) ));
 158                         ret = False;
 159                         goto out;
 160                 }
 161
 162                 if (cs.curr_connections >= max_connections) {
 163                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 164                                 max_connections, name ));
 165                         ret = False;
 166                         goto out;
 167                 }
 168         }
 169
 170         DEBUG(5,("claiming %s %d\n",name,max_connections));
 171
 172         ZERO_STRUCT(key);
 173         key.pid = sys_getpid();
 174         key.cnum = conn?conn->cnum:-1;
 175         fstrcpy(key.name, name);
 176
 177         kbuf.dptr = (char *)&key;
 178         kbuf.dsize = sizeof(key);
 179
 180         /* fill in the crec */
 181         ZERO_STRUCT(crec);
 182         crec.magic = 0x280267;
 183         crec.pid = sys_getpid();
 184         crec.cnum = conn?conn->cnum:-1;
 185         if (conn) {
 186                 crec.uid = conn->uid;
 187                 crec.gid = conn->gid;
 188                 StrnCpy(crec.name,
 189                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 190         }
 191         crec.start = time(NULL);
 192
 193         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 194         StrnCpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 195
 196         dbuf.dptr = (char *)&crec;
 197         dbuf.dsize = sizeof(crec);
 198
 199         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 200                 DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
 201                         tdb_errorstr(tdb) ));
 202                 ret = False;
 203         }
 204
 205   out:
 206
 207         if (rec_locked)
 208                 tdb_chainunlock(tdb, lockkey);
 209
 210         return ret;
 211 }