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, const char *name, TDB_DATA *pkbuf, struct connections_key *pkey)
  39 {
  40         ZERO_STRUCTP(pkey);
  41         ZERO_STRUCTP(pkbuf);
  42         pkey->pid = sys_getpid();
  43         pkey->cnum = conn?conn->cnum:-1;
  44         fstrcpy(pkey->name, name);
  45
  46         pkbuf->dptr = (char *)pkey;
  47         pkbuf->dsize = sizeof(*pkey);
  48 }
  49
  50 /****************************************************************************
  51  Delete a connection record.
  52 ****************************************************************************/
  53
  54 BOOL yield_connection(connection_struct *conn, const char *name)
  55 {
  56         struct connections_key key;
  57         TDB_DATA kbuf;
  58
  59         if (!tdb)
  60                 return False;
  61
  62         DEBUG(3,("Yielding connection to %s\n",name));
  63
  64         make_conn_key(conn, name, &kbuf, &key);
  65
  66         if (tdb_delete(tdb, kbuf) != 0) {
  67                 int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
  68                 DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
  69                         name, tdb_errorstr(tdb) ));
  70                 return (False);
  71         }
  72
  73         return(True);
  74 }
  75
  76 struct count_stat {
  77         pid_t mypid;
  78         int curr_connections;
  79         char *name;
  80         BOOL Clear;
  81 };
  82
  83 /****************************************************************************
  84  Count the entries belonging to a service in the connection db.
  85 ****************************************************************************/
  86
  87 static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
  88 {
  89         struct connections_data crec;
  90         struct count_stat *cs = (struct count_stat *)udp;
  91
  92         if (dbuf.dsize != sizeof(crec))
  93                 return 0;
  94
  95         memcpy(&crec, dbuf.dptr, sizeof(crec));
  96
  97         if (crec.cnum == -1)
  98                 return 0;
  99
 100         /* If the pid was not found delete the entry from connections.tdb */
 101
 102         if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
 103                 DEBUG(2,("pid %u doesn't exist - deleting connections %d [%s]\n",
 104                         (unsigned int)crec.pid, crec.cnum, crec.name));
 105                 if (tdb_delete(the_tdb, kbuf) != 0)
 106                         DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
 107                 return 0;
 108         }
 109
 110         if (strequal(crec.name, cs->name))
 111                 cs->curr_connections++;
 112
 113         return 0;
 114 }
 115
 116 /****************************************************************************
 117  Claim an entry in the connections database.
 118 ****************************************************************************/
 119
 120 BOOL claim_connection(connection_struct *conn, const char *name,int max_connections,BOOL Clear, uint32 msg_flags)
 121 {
 122         struct connections_key key;
 123         struct connections_data crec;
 124         TDB_DATA kbuf, dbuf;
 125
 126         if (!tdb)
 127                 tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT,
 128                                O_RDWR | O_CREAT, 0644);
 129
 130         if (!tdb)
 131                 return False;
 132
 133         /*
 134          * Enforce the max connections parameter.
 135          */
 136
 137         if (max_connections > 0) {
 138                 struct count_stat cs;
 139
 140                 cs.mypid = sys_getpid();
 141                 cs.curr_connections = 0;
 142                 cs.name = lp_servicename(SNUM(conn));
 143                 cs.Clear = Clear;
 144
 145                 /*
 146                  * This has a race condition, but locking the chain before hand is worse
 147                  * as it leads to deadlock.
 148                  */
 149
 150                 if (tdb_traverse(tdb, count_fn, &cs) == -1) {
 151                         DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
 152                                 tdb_errorstr(tdb) ));
 153                         return False;
 154                 }
 155
 156                 if (cs.curr_connections >= max_connections) {
 157                         DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
 158                                 max_connections, name ));
 159                         return False;
 160                 }
 161         }
 162
 163         DEBUG(5,("claiming %s %d\n",name,max_connections));
 164
 165         make_conn_key(conn, name, &kbuf, &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                 safe_strcpy(crec.name,
 176                             lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 177         }
 178         crec.start = time(NULL);
 179         crec.bcast_msg_flags = msg_flags;
 180
 181         safe_strcpy(crec.machine,get_remote_machine_name(),sizeof(crec.machine)-1);
 182         safe_strcpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);
 183
 184         dbuf.dptr = (char *)&crec;
 185         dbuf.dsize = sizeof(crec);
 186
 187         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 188                 DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
 189                         tdb_errorstr(tdb) ));
 190                 return False;
 191         }
 192
 193         return True;
 194 }
 195
 196 BOOL register_message_flags(BOOL doreg, uint32 msg_flags)
 197 {
 198         struct connections_key key;
 199         struct connections_data *pcrec;
 200         TDB_DATA kbuf, dbuf;
 201
 202         if (!tdb)
 203                 return False;
 204
 205         DEBUG(10,("register_message_flags: %s flags 0x%x\n",
 206                 doreg ? "adding" : "removing",
 207                 (unsigned int)msg_flags ));
 208
 209         make_conn_key(NULL, "", &kbuf, &key);
 210
 211         dbuf = tdb_fetch(tdb, kbuf);
 212         if (!dbuf.dptr) {
 213                 DEBUG(0,("register_message_flags: tdb_fetch failed\n"));
 214                 return False;
 215         }
 216
 217         pcrec = (struct connections_data *)dbuf.dptr;
 218         pcrec->bcast_msg_flags = msg_flags;
 219         if (doreg)
 220                 pcrec->bcast_msg_flags |= msg_flags;
 221         else
 222                 pcrec->bcast_msg_flags &= ~msg_flags;
 223
 224         if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
 225                 DEBUG(0,("register_message_flags: tdb_store failed with error %s.\n",
 226                         tdb_errorstr(tdb) ));
 227                 SAFE_FREE(dbuf.dptr);
 228                 return False;
 229         }
 230
 231         DEBUG(10,("register_message_flags: new flags 0x%x\n",
 232                 (unsigned int)pcrec->bcast_msg_flags ));
 233
 234         SAFE_FREE(dbuf.dptr);
 235         return True;
 236 }