freebsd-dev/usr.sbin/nscd/config.h
Stefan Eßer a397989d4e Add the possibility to specify a threshold for the number of negative cache
results required to have the cache return lookup failure.

A new configuration parameter is introduced, which must be set to a value
greater than 1 to activate this feature. The default behavior is unchanged.

The purpose of this change is to allow probes for the existence of an entry
(which are expected to fail), before that entry is added to one of the
queried databases, without the cache returning the stale information from
the probe query until that cache entry expires. If, for example, a new user
account is created after checking that the new account name is available,
the negative cache entry would prevent immediate access to the account.

For that example, the new configuration option

negative-confidence-threshold passwd 2

will require a second negative query result to consider the negative cache
entry for a passwd entry valid, but if the user account has been created
between the queries, then the positive query result from the second query
will be cached and returned.
2012-07-04 09:02:12 +00:00

151 lines
5.0 KiB
C

/*-
* Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef __NSCD_CONFIG_H__
#define __NSCD_CONFIG_H__
#include "cachelib.h"
#define DEFAULT_QUERY_TIMEOUT 8
#define DEFAULT_THREADS_NUM 8
#define DEFAULT_COMMON_ENTRY_TIMEOUT 10
#define DEFAULT_MP_ENTRY_TIMEOUT 60
#define DEFAULT_CACHE_HT_SIZE 257
#define INITIAL_ENTRIES_CAPACITY 8
#define DEFAULT_SOCKET_PATH "/var/run/nscd"
#define DEFAULT_PIDFILE_PATH "/var/run/nscd.pid"
#define DEFAULT_POSITIVE_ELEMENTS_SIZE (2048)
#define DEFAULT_POSITIVE_LIFETIME (3600)
#define DEFAULT_POSITIVE_CONF_THRESH (1)
#define DEFAULT_NEGATIVE_ELEMENTS_SIZE (2048)
#define DEFAULT_NEGATIVE_LIFETIME (60)
#define DEFAULT_NEGATIVE_CONF_THRESH (1) /* (2) ??? */
#define DEFAULT_MULTIPART_ELEMENTS_SIZE (1024 * 8)
#define DEFAULT_MULITPART_SESSIONS_SIZE (1024)
#define DEFAULT_MULITPART_LIFETIME (3600)
extern const char *c_default_entries[6];
/*
* Configuration entry represents the details of each cache entry in the
* config file (i.e. passwd or group). Its purpose also is to acquire locks
* of three different types (for usual read/write caching, for multipart
* caching and for caching of the negative results) for that cache entry.
*/
struct configuration_entry {
struct common_cache_entry_params positive_cache_params;
struct common_cache_entry_params negative_cache_params;
struct mp_cache_entry_params mp_cache_params;
/*
* configuration_entry holds pointers for all actual cache_entries,
* which are used for it. There is one for positive caching, one for
* for negative caching, and several (one per each euid/egid) for
* multipart caching.
*/
cache_entry positive_cache_entry;
cache_entry negative_cache_entry;
cache_entry *mp_cache_entries;
size_t mp_cache_entries_size;
struct timeval common_query_timeout;
struct timeval mp_query_timeout;
char *name;
pthread_mutex_t positive_cache_lock;
pthread_mutex_t negative_cache_lock;
pthread_mutex_t mp_cache_lock;
int perform_actual_lookups;
int enabled;
};
/*
* Contains global configuration options and array of all configuration entries
*/
struct configuration {
char *pidfile_path;
char *socket_path;
struct configuration_entry **entries;
size_t entries_capacity;
size_t entries_size;
pthread_rwlock_t rwlock;
mode_t socket_mode;
int force_unlink;
int query_timeout;
int threads_num;
};
enum config_entry_lock_type {
CELT_POSITIVE,
CELT_NEGATIVE,
CELT_MULTIPART
};
struct configuration *init_configuration(void);
void destroy_configuration(struct configuration *);
void fill_configuration_defaults(struct configuration *);
int add_configuration_entry(struct configuration *,
struct configuration_entry *);
struct configuration_entry *create_def_configuration_entry(const char *);
void destroy_configuration_entry(struct configuration_entry *);
size_t configuration_get_entries_size(struct configuration *);
struct configuration_entry *configuration_get_entry(struct configuration *,
size_t);
struct configuration_entry *configuration_find_entry(struct configuration *,
const char *);
int configuration_entry_add_mp_cache_entry(struct configuration_entry *,
cache_entry);
cache_entry configuration_entry_find_mp_cache_entry(
struct configuration_entry *, const char *);
int configuration_entry_find_mp_cache_entries(struct configuration_entry *,
const char *, cache_entry **, cache_entry **);
void configuration_lock_rdlock(struct configuration *config);
void configuration_lock_wrlock(struct configuration *config);
void configuration_unlock(struct configuration *config);
void configuration_lock_entry(struct configuration_entry *,
enum config_entry_lock_type);
void configuration_unlock_entry(struct configuration_entry *,
enum config_entry_lock_type);
#endif