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c793fb8a66
If there's another process around there will typically be at most one process. So there is no real need to run the plural version of serverid_exists. Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Jeremy Allison <jra@samba.org>
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/*
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* Unix SMB/CIFS implementation.
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* Utils around server_id_db with more dependencies
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* Copyright (C) Volker Lendecke 2014
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "replace.h"
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#include "server_id_db_util.h"
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#include "serverid.h"
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static int server_id_db_check_exclusive(
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struct server_id_db *db, const char *name,
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unsigned num_servers, struct server_id *servers);
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int server_id_db_set_exclusive(struct server_id_db *db, const char *name)
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{
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int ret;
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unsigned num_servers;
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struct server_id *servers;
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ret = server_id_db_add(db, name);
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if (ret != 0) {
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return ret;
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}
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ret = server_id_db_lookup(db, name, talloc_tos(),
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&num_servers, &servers);
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if (ret != 0) {
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goto done;
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}
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/*
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* Remove entries from the server_id_db for processes that have died
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* and could not clean up. This is racy, as two processes could
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* simultaneously try to register a name. Both would succeed in the
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* server_id_db_add call, and both would see their peer active during
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* the check_exclusive call. Both would get an EEXIST, and nobody
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* would be able to register itself. But this is okay, as this is
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* meant to be a cleanup routine, and normally only one daemon should
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* start up at a time anyway. Getting this "right" would mean we would
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* have to add locking to server_id_db, or add a dependency on
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* serverids_exist to server_id_db. Both are too heavy-weight for my
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* taste.
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*/
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ret = server_id_db_check_exclusive(db, name, num_servers, servers);
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TALLOC_FREE(servers);
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done:
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if (ret != 0) {
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server_id_db_remove(db, name);
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}
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return ret;
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}
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static int server_id_db_check_exclusive(
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struct server_id_db *db, const char *name,
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unsigned num_servers, struct server_id *servers)
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{
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struct server_id me = server_id_db_pid(db);
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int i;
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for (i=0; i<num_servers; i++) {
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int ret;
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if (server_id_same_process(&me, &servers[i])) {
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/*
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* I am always around ... :-)
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*/
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continue;
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}
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if (serverid_exists(&servers[i])) {
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return EEXIST;
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}
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ret = server_id_db_prune_name(db, name, servers[i]);
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if (ret != 0) {
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return ret;
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}
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}
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return 0;
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}
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