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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 "lib/util/server_id.h"
#include "serverid.h"
#include "lib/util/samba_util.h"
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);
unsigned i;
for (i=0; i<num_servers; i++) {
int ret;
if (server_id_same_process(&me, &servers[i])) {
/*
* I am always around ... :-)
*/
continue;
}
if (serverid_exists(&servers[i])) {
return EEXIST;
}
ret = server_id_db_prune_name(db, name, servers[i]);
if (ret != 0) {
return ret;
}
}
return 0;
}
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