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/*
* Unix SMB / CIFS implementation .
* Utils around server_id_db with more dependencies
* Copyright ( C ) Volker Lendecke 2014
*
* 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 3 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 , see < http : //www.gnu.org/licenses/>.
*/
# include "replace.h"
# include "server_id_db_util.h"
# include "serverid.h"
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# include "lib/util/samba_util.h"
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static int server_id_db_check_exclusive (
struct server_id_db * db , const char * name ,
unsigned num_servers , struct server_id * servers ) ;
int server_id_db_set_exclusive ( struct server_id_db * db , const char * name )
{
int ret ;
unsigned num_servers ;
struct server_id * servers ;
ret = server_id_db_add ( db , name ) ;
if ( ret ! = 0 ) {
return ret ;
}
ret = server_id_db_lookup ( db , name , talloc_tos ( ) ,
& num_servers , & servers ) ;
if ( ret ! = 0 ) {
goto done ;
}
/*
* Remove entries from the server_id_db for processes that have died
* and could not clean up . This is racy , as two processes could
* simultaneously try to register a name . Both would succeed in the
* server_id_db_add call , and both would see their peer active during
* the check_exclusive call . Both would get an EEXIST , and nobody
* would be able to register itself . But this is okay , as this is
* meant to be a cleanup routine , and normally only one daemon should
* start up at a time anyway . Getting this " right " would mean we would
* have to add locking to server_id_db , or add a dependency on
* serverids_exist to server_id_db . Both are too heavy - weight for my
* taste .
*/
ret = server_id_db_check_exclusive ( db , name , num_servers , servers ) ;
TALLOC_FREE ( servers ) ;
done :
if ( ret ! = 0 ) {
server_id_db_remove ( db , name ) ;
}
return ret ;
}
static int server_id_db_check_exclusive (
struct server_id_db * db , const char * name ,
unsigned num_servers , struct server_id * servers )
{
struct server_id me = server_id_db_pid ( db ) ;
int i ;
for ( i = 0 ; i < num_servers ; i + + ) {
int ret ;
if ( server_id_same_process ( & me , & servers [ i ] ) ) {
/*
* I am always around . . . : - )
*/
continue ;
}
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if ( serverid_exists ( & servers [ i ] ) ) {
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return EEXIST ;
}
ret = server_id_db_prune_name ( db , name , servers [ i ] ) ;
if ( ret ! = 0 ) {
return ret ;
}
}
return 0 ;
}