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
  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         dos_to_unix(key.name, True);           /* Convert key to unix-codepage */
  57
  58         kbuf.dptr = (char *)&key;
  59         kbuf.dsize = sizeof(key);
  60
  61         tdb_delete(tdb, kbuf);
  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                 tdb_delete(the_tdb, kbuf);
  96                 return 0;
  97         }
  98
  99         if (strequal(crec.name, cs->name))
 100                 cs->curr_connections++;
 101
 102         return 0;
 103 }
 104
 105 /****************************************************************************
 106  Claim an entry in the connections database.
 107 ****************************************************************************/
 108
 109 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear)
 110 {
 111         struct connections_key key;
 112         struct connections_data crec;
 113         TDB_DATA kbuf, dbuf, lockkey;
 114         BOOL rec_locked = False;
 115         BOOL ret = True;
 116
 117         if (!tdb) {
 118                 tdb = tdb_open(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST,
 119                                O_RDWR | O_CREAT, 0644);
 120         }
 121         if (!tdb)
 122                 return False;
 123
 124         /*
 125          * Enforce the max connections parameter.
 126          */
 127
 128         if (max_connections > 0) {
 129                 struct count_stat cs;
 130
 131                 cs.mypid = sys_getpid();
 132                 cs.curr_connections = 0;
 133                 cs.name = lp_servicename(SNUM(conn));
 134                 cs.Clear = Clear;
 135
 136                 lockkey.dptr = cs.name;
 137                 lockkey.dsize = strlen(cs.name)+1;
 138
 139                 /*
 140                  * Go through and count the connections with hash chain representing the service name
 141                  * locked. This is slow but removes race conditions. JRA.
 142                  */
 143
 144                 if (tdb_chainlock(tdb, lockkey))
 145                         return False;
 146
 147                 rec_locked = True;
 148
 149                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 150                         DEBUG(0,("claim_connection: traverse of connections.tdb failed.\n"));
 151                         ret = False;
 152                         goto out;
 153                 }
 154
 155                 if (cs.curr_connections >= max_connections) {
 156                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 157                                 max_connections, name ));
 158                         ret = False;
 159                         goto out;
 160                 }
 161         }
 162
 163         DEBUG(5,("claiming %s %d\n",name,max_connections));
 164
 165         ZERO_STRUCT(key);
 166         key.pid = sys_getpid();
 167         key.cnum = conn?conn->cnum:-1;
 168         fstrcpy(key.name, name);
 169         dos_to_unix(key.name, True);           /* Convert key to unix-codepage */
 170
 171         kbuf.dptr = (char *)&key;
 172         kbuf.dsize = sizeof(key);
 173
 174         /* fill in the crec */
 175         ZERO_STRUCT(crec);
 176         crec.magic = 0x280267;
 177         crec.pid = sys_getpid();
 178         crec.cnum = conn?conn->cnum:-1;
 179         if (conn) {
 180                 crec.uid = conn->uid;
 181                 crec.gid = conn->gid;
 182                 StrnCpy(crec.name,
 183                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 184         }
 185         crec.start = time(NULL);
 186
 187         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 188         StrnCpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 189
 190         dbuf.dptr = (char *)&crec;
 191         dbuf.dsize = sizeof(crec);
 192
 193         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0)
 194                 ret = False;
 195
 196   out:
 197
 198         if (rec_locked)
 199                 tdb_chainunlock(tdb, lockkey);
 200
 201         return ret;
 202 }