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 static TDB_CONTEXT *tdb;
  24
  25 /****************************************************************************
  26  Return the connection tdb context (used for message send all).
  27 ****************************************************************************/
  28
  29 TDB_CONTEXT *conn_tdb_ctx(void)
  30 {
  31         if (!tdb)
  32                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
  33                                O_RDWR | O_CREAT, 0644);
  34
  35         return tdb;
  36 }
  37
  38 static void make_conn_key(connection_struct *conn,char *name, TDB_DATA *pkbuf, struct connections_key *pkey)
  39 {
  40         ZERO_STRUCTP(pkey);
  41         pkey->pid = sys_getpid();
  42         pkey->cnum = conn?conn->cnum:-1;
  43         fstrcpy(pkey->name, name);
  44
  45         pkbuf->dptr = (char *)pkey;
  46         pkbuf->dsize = sizeof(*pkey);
  47 }
  48
  49 /****************************************************************************
  50  Delete a connection record.
  51 ****************************************************************************/
  52
  53 BOOL yield_connection(connection_struct *conn,char *name)
  54 {
  55         struct connections_key key;
  56         TDB_DATA kbuf;
  57
  58         if (!tdb)
  59                 return False;
  60
  61         DEBUG(3,("Yielding connection to %s\n",name));
  62
  63         make_conn_key(conn, name, &kbuf, &key);
  64
  65         if (tdb_delete(tdb, kbuf) != 0) {
  66                 int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
  67                 DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  68                         name, tdb_errorstr(tdb) ));
  69                 return (False);
  70         }
  71
  72         return(True);
  73 }
  74
  75 struct count_stat {
  76         pid_t mypid;
  77         int curr_connections;
  78         char *name;
  79         BOOL Clear;
  80 };
  81
  82 /****************************************************************************
  83  Count the entries belonging to a service in the connection db.
  84 ****************************************************************************/
  85
  86 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  87 {
  88         struct connections_data crec;
  89         struct count_stat *cs = (struct count_stat *)udp;
  90
  91         if (dbuf.dsize != sizeof(crec))
  92                 return 0;
  93
  94         memcpy(&crec, dbuf.dptr, sizeof(crec));
  95
  96         if (crec.cnum == -1)
  97                 return 0;
  98
  99         /* If the pid was not found delete the entry from connections.tdb */
 100
 101         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
 102                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
 103                         (unsigned int)crec.pid, crec.cnum, crec.name));
 104                 if (tdb_delete(the_tdb, kbuf) != 0)
 105                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
 106                 return 0;
 107         }
 108
 109         if (strequal(crec.name, cs->name))
 110                 cs->curr_connections++;
 111
 112         return 0;
 113 }
 114
 115 /****************************************************************************
 116  Claim an entry in the connections database.
 117 ****************************************************************************/
 118
 119 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear, uint32 msg_flags)
 120 {
 121         struct connections_key key;
 122         struct connections_data crec;
 123         TDB_DATA kbuf, dbuf;
 124
 125         if (!tdb)
 126                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 127                                O_RDWR | O_CREAT, 0644);
 128
 129         if (!tdb)
 130                 return False;
 131
 132         /*
 133          * Enforce the max connections parameter.
 134          */
 135
 136         if (max_connections > 0) {
 137                 struct count_stat cs;
 138
 139                 cs.mypid = sys_getpid();
 140                 cs.curr_connections = 0;
 141                 cs.name = lp_servicename(SNUM(conn));
 142                 cs.Clear = Clear;
 143
 144                 /*
 145                  * This has a race condition, but locking the chain before hand is worse
 146                  * as it leads to deadlock.
 147                  */
 148
 149                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 150                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 151                                 tdb_errorstr(tdb) ));
 152                         return False;
 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                         return False;
 159                 }
 160         }
 161
 162         DEBUG(5,("claiming %s %d\n",name,max_connections));
 163
 164         make_conn_key(conn, name, &kbuf, &key);
 165
 166         /* fill in the crec */
 167         ZERO_STRUCT(crec);
 168         crec.magic = 0x280267;
 169         crec.pid = sys_getpid();
 170         crec.cnum = conn?conn->cnum:-1;
 171         if (conn) {
 172                 crec.uid = conn->uid;
 173                 crec.gid = conn->gid;
 174                 StrnCpy(crec.name,
 175                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 176         }
 177         crec.start = time(NULL);
 178         crec.bcast_msg_flags = msg_flags;
 179
 180         StrnCpy(crec.machine,get_remote_machine_name(),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 }
 194
 195 BOOL register_message_flags(BOOL doreg, uint32 msg_flags)
 196 {
 197         struct connections_key key;
 198         struct connections_data *pcrec;
 199         TDB_DATA kbuf, dbuf;
 200
 201         if (!tdb)
 202                 return False;
 203
 204         DEBUG(10,("register_message_flags: %s flags 0x%x\n",
 205                 doreg ? "adding" : "removing",
 206                 (unsigned int)msg_flags ));
 207
 208         make_conn_key(NULL, "", &kbuf, &key);
 209
 210         dbuf = tdb_fetch(tdb, kbuf);
 211         if (!dbuf.dptr) {
 212                 DEBUG(0,("register_message_flags: tdb_fetch failed\n"));
 213                 return False;
 214         }
 215
 216         pcrec = (struct connections_data *)dbuf.dptr;
 217         pcrec->bcast_msg_flags = msg_flags;
 218         if (doreg)
 219                 pcrec->bcast_msg_flags |= msg_flags;
 220         else
 221                 pcrec->bcast_msg_flags &= ~msg_flags;
 222
 223         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 224                 DEBUG(0,("register_message_flags: tdb_store failed with error %s.\n",
 225                         tdb_errorstr(tdb) ));
 226                 SAFE_FREE(dbuf.dptr);
 227                 return False;
 228         }
 229
 230         DEBUG(10,("register_message_flags: new flags 0x%x\n",
 231                 (unsigned int)pcrec->bcast_msg_flags ));
 232
 233         SAFE_FREE(dbuf.dptr);
 234         return True;
 235 }