smbd/connection.c

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/* 
   Unix SMB/CIFS implementation.
   connection claim routines
   Copyright (C) Andrew Tridgell 1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

static TDB_CONTEXT *tdb;

/****************************************************************************
 Return the connection tdb context (used for message send all).
****************************************************************************/

TDB_CONTEXT *conn_tdb_ctx(void)
{
        if (!tdb)
                tdb = tdb_open_log(lock_path("connections.tdb"), 0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
                               O_RDWR | O_CREAT, 0644);

        return tdb;
}

static void make_conn_key(connection_struct *conn, const char *name, TDB_DATA *pkbuf, struct connections_key *pkey)
{
        ZERO_STRUCTP(pkey);
        pkey->pid = procid_self();
        pkey->cnum = conn?conn->cnum:-1;
        fstrcpy(pkey->name, name);
#ifdef DEVELOPER
        /* valgrind fixer... */
        {
                size_t sl = strlen(pkey->name);
                if (sizeof(fstring)-sl)
                        memset(&pkey->name[sl], '\0', sizeof(fstring)-sl);
        }
#endif

        pkbuf->dptr = (char *)pkey;
        pkbuf->dsize = sizeof(*pkey);
}

/****************************************************************************
 Delete a connection record.
****************************************************************************/

BOOL yield_connection(connection_struct *conn, const char *name)
{
        struct connections_key key;
        TDB_DATA kbuf;

        if (!tdb)
                return False;

        DEBUG(3,("Yielding connection to %s\n",name));

        make_conn_key(conn, name, &kbuf, &key);

        if (tdb_delete(tdb, kbuf) != 0) {
                int dbg_lvl = (!conn && (tdb_error(tdb) == TDB_ERR_NOEXIST)) ? 3 : 0;
                DEBUG(dbg_lvl,("yield_connection: tdb_delete for name %s failed with error %s.\n",
                        name, tdb_errorstr(tdb) ));
                return (False);
        }

        return(True);
}

struct count_stat {
        pid_t mypid;
        int curr_connections;
        const char *name;
        BOOL Clear;
};

/****************************************************************************
 Count the entries belonging to a service in the connection db.
****************************************************************************/

static int count_fn( TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, void *udp)
{
        struct connections_data crec;
        struct count_stat *cs = (struct count_stat *)udp;
 
        if (dbuf.dsize != sizeof(crec))
                return 0;

        memcpy(&crec, dbuf.dptr, sizeof(crec));
 
        if (crec.cnum == -1)
                return 0;

        /* If the pid was not found delete the entry from connections.tdb */

        if (cs->Clear && !process_exists(crec.pid) && (errno == ESRCH)) {
                DEBUG(2,("pid %s doesn't exist - deleting connections %d [%s]\n",
                        procid_str_static(&crec.pid), crec.cnum, crec.servicename));
                if (tdb_delete(the_tdb, kbuf) != 0)
                        DEBUG(0,("count_fn: tdb_delete failed with error %s\n", tdb_errorstr(tdb) ));
                return 0;
        }

        if (strequal(crec.servicename, cs->name))
                cs->curr_connections++;

        return 0;
}

/****************************************************************************
 Claim an entry in the connections database.
****************************************************************************/

int count_current_connections( const char *sharename, BOOL clear  )
{
        struct count_stat cs;

        cs.mypid = sys_getpid();
        cs.curr_connections = 0;
        cs.name = sharename;
        cs.Clear = clear;

        /*
         * This has a race condition, but locking the chain before hand is worse
         * as it leads to deadlock.
         */

        if (tdb_traverse(tdb, count_fn, &cs) == -1) {
                DEBUG(0,("claim_connection: traverse of connections.tdb failed with error %s.\n",
                        tdb_errorstr(tdb) ));
                return False;
        }
        
        return cs.curr_connections;
}

/****************************************************************************
 Claim an entry in the connections database.
****************************************************************************/

BOOL claim_connection(connection_struct *conn, const char *name,int max_connections,BOOL Clear, uint32 msg_flags)
{
        struct connections_key key;
        struct connections_data crec;
        TDB_DATA kbuf, dbuf;

        if (!tdb) {
                if ( (tdb =conn_tdb_ctx()) == NULL ) {
                        return False;
                }
        }
        
        /*
         * Enforce the max connections parameter.
         */

        if (max_connections > 0) {
                int curr_connections;
                
                curr_connections = count_current_connections( lp_servicename(SNUM(conn)), True );

                if (curr_connections >= max_connections) {
                        DEBUG(1,("claim_connection: Max connections (%d) exceeded for %s\n",
                                max_connections, name ));
                        return False;
                }
        }

        DEBUG(5,("claiming %s %d\n",name,max_connections));

        make_conn_key(conn, name, &kbuf, &key);

        /* fill in the crec */
        ZERO_STRUCT(crec);
        crec.magic = 0x280267;
        crec.pid = procid_self();
        crec.cnum = conn?conn->cnum:-1;
        if (conn) {
                crec.uid = conn->uid;
                crec.gid = conn->gid;
                safe_strcpy(crec.servicename,
                            lp_servicename(SNUM(conn)),sizeof(crec.servicename)-1);
        }
        crec.start = time(NULL);
        crec.bcast_msg_flags = msg_flags;
        
        safe_strcpy(crec.machine,get_remote_machine_name(),sizeof(crec.machine)-1);
        safe_strcpy(crec.addr,conn?conn->client_address:client_addr(),sizeof(crec.addr)-1);

        dbuf.dptr = (char *)&crec;
        dbuf.dsize = sizeof(crec);

        if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
                DEBUG(0,("claim_connection: tdb_store failed with error %s.\n",
                        tdb_errorstr(tdb) ));
                return False;
        }

        return True;
}

BOOL register_message_flags(BOOL doreg, uint32 msg_flags)
{
        struct connections_key key;
        struct connections_data *pcrec;
        TDB_DATA kbuf, dbuf;

        if (!tdb)
                return False;

        DEBUG(10,("register_message_flags: %s flags 0x%x\n",
                doreg ? "adding" : "removing",
                (unsigned int)msg_flags ));

        make_conn_key(NULL, "", &kbuf, &key);

        dbuf = tdb_fetch(tdb, kbuf);
        if (!dbuf.dptr) {
                DEBUG(0,("register_message_flags: tdb_fetch failed: %s\n",
                        tdb_errorstr(tdb)));
                return False;
        }

        pcrec = (struct connections_data *)dbuf.dptr;
        if (doreg)
                pcrec->bcast_msg_flags |= msg_flags;
        else
                pcrec->bcast_msg_flags &= ~msg_flags;

        if (tdb_store(tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
                DEBUG(0,("register_message_flags: tdb_store failed: %s.\n",
                        tdb_errorstr(tdb) ));
                SAFE_FREE(dbuf.dptr);
                return False;
        }

        DEBUG(10,("register_message_flags: new flags 0x%x\n",
                (unsigned int)pcrec->bcast_msg_flags ));

        SAFE_FREE(dbuf.dptr);
        return True;
}

/*********************************************************************
*********************************************************************/

static TDB_DATA* make_pipe_rec_key( struct pipe_open_rec *prec )
{
        TDB_DATA *kbuf = NULL;
        fstring key_string;
        
        if ( !prec )
                return NULL;
        
        if ( (kbuf = TALLOC_P(prec, TDB_DATA)) == NULL ) {
                return NULL;
        }
        
        snprintf( key_string, sizeof(key_string), "%s/%d/%d",
                prec->name, procid_to_pid(&prec->pid), prec->pnum );
                
        if ( (kbuf->dptr = talloc_strdup(prec, key_string)) == NULL )
                return NULL;
                
        kbuf->dsize = strlen(key_string)+1;
        
        return kbuf;
}

/*********************************************************************
*********************************************************************/

static void fill_pipe_open_rec( struct pipe_open_rec *prec, smb_np_struct *p )
{
        prec->pid = pid_to_procid(sys_getpid());
        prec->pnum = p->pnum;
        prec->uid = geteuid();
        fstrcpy( prec->name, p->name );

        return;
}

/*********************************************************************
*********************************************************************/

BOOL store_pipe_opendb( smb_np_struct *p )
{
        struct pipe_open_rec *prec;
        TDB_DATA *key;
        TDB_DATA data;
        TDB_CONTEXT *pipe_tdb;
        BOOL ret = False;
        
        if ( (prec = TALLOC_P( NULL, struct pipe_open_rec)) == NULL ) {
                DEBUG(0,("store_pipe_opendb: talloc failed!\n"));
                return False;
        }
        
        fill_pipe_open_rec( prec, p );
        if ( (key = make_pipe_rec_key( prec )) == NULL ) {
                goto done;
        }
        
        data.dptr = (char*)prec;
        data.dsize = sizeof(struct pipe_open_rec);
        
        if ( (pipe_tdb = conn_tdb_ctx() ) == NULL ) {
                goto done;
        }
        
        ret = (tdb_store( pipe_tdb, *key, data, TDB_REPLACE ) != -1);
        
done:
        TALLOC_FREE( prec );    
        return ret;
}

/*********************************************************************
*********************************************************************/

BOOL delete_pipe_opendb( smb_np_struct *p )
{
        struct pipe_open_rec *prec;
        TDB_DATA *key;
        TDB_CONTEXT *pipe_tdb;
        BOOL ret = False;
        
        if ( (prec = TALLOC_P( NULL, struct pipe_open_rec)) == NULL ) {
                DEBUG(0,("store_pipe_opendb: talloc failed!\n"));
                return False;
        }
        
        fill_pipe_open_rec( prec, p );
        if ( (key = make_pipe_rec_key( prec )) == NULL ) {
                goto done;
        }
        
        if ( (pipe_tdb = conn_tdb_ctx() ) == NULL ) {
                goto done;
        }

        ret = (tdb_delete( pipe_tdb, *key ) != -1 );
        
done:
        TALLOC_FREE( prec );
        return ret;
}

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