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 /****************************************************************************
  29  Return the connection tdb context (used for message send all).
  30 ****************************************************************************/
  31
  32 TDB_CONTEXT *conn_tdb_ctx(void)
  33 {
  34         return tdb;
  35 }
  36
  37 /****************************************************************************
  38  Delete a connection record.
  39 ****************************************************************************/
  40
  41 BOOL yield_connection(connection_struct *conn,const char *name)
  42 {
  43         struct connections_key key;
  44         TDB_DATA kbuf;
  45
  46         if (!tdb) return False;
  47
  48         DEBUG(3,("Yielding connection to %s\n",name));
  49
  50         ZERO_STRUCT(key);
  51         key.pid = sys_getpid();
  52         key.cnum = conn?conn->cnum:-1;
  53         fstrcpy(key.name, name);
  54         dos_to_unix(key.name);           /* Convert key to unix-codepage */
  55
  56         kbuf.dptr = (char *)&key;
  57         kbuf.dsize = sizeof(key);
  58
  59         if (tdb_delete(tdb, kbuf) != 0) {
  60                 int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
  61                 DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  62                         name, tdb_errorstr(tdb) ));
  63                 return (False);
  64         }
  65
  66         return(True);
  67 }
  68
  69 struct count_stat {
  70         pid_t mypid;
  71         int curr_connections;
  72         char *name;
  73         BOOL Clear;
  74 };
  75
  76 /****************************************************************************
  77  Count the entries belonging to a service in the connection db.
  78 ****************************************************************************/
  79
  80 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  81 {
  82         struct connections_data crec;
  83         struct count_stat *cs = (struct count_stat *)udp;
  84
  85         if (dbuf.dsize != sizeof(crec))
  86                 return 0;
  87
  88         memcpy(&crec, dbuf.dptr, sizeof(crec));
  89
  90         if (crec.cnum == -1)
  91                 return 0;
  92
  93         /* If the pid was not found delete the entry from connections.tdb */
  94
  95         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
  96                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
  97                         (unsigned int)crec.pid, crec.cnum, crec.name));
  98                 if (tdb_delete(the_tdb, kbuf) != 0)
  99                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
 100                 return 0;
 101         }
 102
 103         if (strequal(crec.name, cs->name))
 104                 cs->curr_connections++;
 105
 106         return 0;
 107 }
 108
 109 /****************************************************************************
 110  Claim an entry in the connections database.
 111 ****************************************************************************/
 112
 113 BOOL claim_connection(connection_struct *conn,const char *name,int max_connections,BOOL Clear)
 114 {
 115         struct connections_key key;
 116         struct connections_data crec;
 117         TDB_DATA kbuf, dbuf;
 118
 119         if (!tdb) {
 120                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 121                                O_RDWR | O_CREAT, 0644);
 122         }
 123         if (!tdb)
 124                 return False;
 125
 126         /*
 127          * Enforce the max connections parameter.
 128          */
 129
 130         if (max_connections > 0) {
 131                 struct count_stat cs;
 132
 133                 cs.mypid = sys_getpid();
 134                 cs.curr_connections = 0;
 135                 cs.name = lp_servicename(SNUM(conn));
 136                 cs.Clear = Clear;
 137
 138                 /*
 139                  * This has a race condition, but locking the chain before hand is worse
 140                  * as it leads to deadlock.
 141                  */
 142
 143                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 144                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 145                                 tdb_errorstr(tdb) ));
 146                         return False;
 147                 }
 148
 149                 if (cs.curr_connections >= max_connections) {
 150                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 151                                 max_connections, name ));
 152                         return False;
 153                 }
 154         }
 155
 156         DEBUG(5,("claiming %s %d\n",name,max_connections));
 157
 158         ZERO_STRUCT(key);
 159         key.pid = sys_getpid();
 160         key.cnum = conn?conn->cnum:-1;
 161         fstrcpy(key.name, name);
 162         dos_to_unix(key.name);           /* Convert key to unix-codepage */
 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
 180         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 181         StrnCpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 182
 183         dbuf.dptr = (char *)&crec;
 184         dbuf.dsize = sizeof(crec);
 185
 186         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 187                 DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
 188                         tdb_errorstr(tdb) ));
 189                 return False;
 190         }
 191
 192         return True;
 193 }