glibc/nscd/nscd.h

/* Copyright (c) 1998, 1999, 2000, 2001, 2003, 2004
   Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#ifndef _NSCD_H
#define _NSCD_H	1

#include <pthread.h>
#include <stdbool.h>
#include <time.h>
#include <sys/uio.h>

/* The declarations for the request and response types are in the file
   "nscd-client.h", which should contain everything needed by client
   functions.  */
#include "nscd-client.h"


/* Handle databases.  */
typedef enum
{
  pwddb,
  grpdb,
  hstdb,
  lastdb
} dbtype;


/* Head of record in data part of database.  */
struct datahead
{
  size_t allocsize;	/* Allocated Bytes.  */
  size_t recsize;	/* Size of the record.  */
  time_t timeout;	/* Time when this entry becomes invalid.  */
  bool notfound;	/* Nonzero if data for key has not been found.  */
  uint8_t nreloads;	/* Reloads without use.  */
  bool usable;		/* False if the entry must be ignored.  */

  /* We need to have the following element aligned for the response
     header data types and their use in the 'struct dataset' types
     defined in the XXXcache.c files.  */
  union
  {
    pw_response_header pwdata;
    gr_response_header grdata;
    hst_response_header hstdata;
    ssize_t align1;
    time_t align2;
  } data[0];
};


/* Default limit on the number of times a value gets reloaded without
   being used in the meantime.  NSCD does not throw a value out as
   soon as it times out.  It tries to reload the value from the
   server.  Only if the value has not been used for so many rounds it
   is removed.  */
#define DEFAULT_RELOAD_LIMIT 5


/* Type for offsets in data part of database.  */
typedef uint32_t ref_t;
/* Value for invalid/no reference.  */
#define ENDREF	UINT32_MAX


/* Structure for one hash table entry.  */
struct hashentry
{
  request_type type:8;		/* Which type of dataset.  */
  bool first;			/* True if this was the original key.  */
  size_t len;			/* Length of key.  */
  ref_t key;			/* Pointer to key.  */
  uid_t owner;			/* If secure table, this is the owner.  */
  ref_t next;			/* Next entry in this hash bucket list.  */
  ref_t packet;			/* Records for the result.  */
  union
  {
    struct hashentry *dellist;	/* Next record to be deleted.  This can be a
				   pointer since only nscd uses this field.  */
    ref_t *prevp;		/* Pointer to field containing forward
				   reference.  */
  };
};


/* Current persistent database version.  */
#define DB_VERSION	1

/* Header of persistent database file.  */
struct database_pers_head
{
  int version;
  int header_size;

  size_t module;
  size_t data_size;

  size_t first_free;		/* Offset of first free byte in data area.  */

  size_t nentries;
  size_t maxnentries;
  size_t maxnsearched;

  uintmax_t poshit;
  uintmax_t neghit;
  uintmax_t posmiss;
  uintmax_t negmiss;

  uintmax_t rdlockdelayed;
  uintmax_t wrlockdelayed;

  uintmax_t addfailed;

  ref_t array[0];
};

/* Structure describing dynamic part of one database.  */
struct database_dyn
{
  pthread_rwlock_t lock;

  int enabled;
  int check_file;
  int persistent;
  const char *filename;
  const char *db_filename;
  time_t file_mtime;
  size_t suggested_module;
  int secure;

  unsigned long int postimeout;	/* In seconds.  */
  unsigned long int negtimeout;	/* In seconds.  */

  int wr_fd;			/* Writable file descriptor.  */
  int ro_fd;			/* Unwritable file descriptor.  */

  const struct iovec *disabled_iov;

  struct database_pers_head *head;
  char *data;
  size_t memsize;
  pthread_mutex_t memlock;
  bool mmap_used;
  bool last_alloc_failed;
};


/* Paths of the file for the persistent storage.  */
#define _PATH_NSCD_PASSWD_DB	"/var/run/nscd/passwd"
#define _PATH_NSCD_GROUP_DB	"/var/run/nscd/group"
#define _PATH_NSCD_HOSTS_DB	"/var/run/nscd/hosts"


/* Global variables.  */
extern struct database_dyn dbs[lastdb];
extern const char *dbnames[lastdb];
extern const char *serv2str[LASTREQ];

extern const struct iovec pwd_iov_disabled;
extern const struct iovec grp_iov_disabled;
extern const struct iovec hst_iov_disabled;


/* Number of threads to run.  */
extern int nthreads;

/* Tables for which we cache data with uid.  */
extern int secure_in_use; /* Is one of the above 1?  */

/* User name to run server processes as.  */
extern const char *server_user;

/* Name and UID of user who is allowed to request statistics.  */
extern const char *stat_user;
extern uid_t stat_uid;

/* Time the server was started.  */
extern time_t start_time;

/* Number of times clients had to wait.  */
extern unsigned long int client_queued;

/* Maximum needed alignment.  */
extern const size_t block_align;

/* Number of times a value is reloaded without being used.  UINT_MAX
   means unlimited.  */
extern unsigned int reload_count;

/* Prototypes for global functions.  */

/* nscd.c */
extern void termination_handler (int signum) __attribute__ ((__noreturn__));
extern int nscd_open_socket (void);

/* connections.c */
extern void nscd_init (void);
extern void close_sockets (void);
extern void start_threads (void) __attribute__ ((__noreturn__));

/* nscd_conf.c */
extern int nscd_parse_file (const char *fname,
			    struct database_dyn dbs[lastdb]);

/* nscd_stat.c */
extern void send_stats (int fd, struct database_dyn dbs[lastdb]);
extern int receive_print_stats (void) __attribute__ ((__noreturn__));

/* cache.c */
extern struct datahead *cache_search (request_type, void *key, size_t len,
				      struct database_dyn *table,
				      uid_t owner);
extern int cache_add (int type, const void *key, size_t len,
		      struct datahead *packet, bool first,
		      struct database_dyn *table, uid_t owner);
extern void prune_cache (struct database_dyn *table, time_t now);

/* pwdcache.c */
extern void addpwbyname (struct database_dyn *db, int fd, request_header *req,
			 void *key, uid_t uid);
extern void addpwbyuid (struct database_dyn *db, int fd, request_header *req,
			void *key, uid_t uid);
extern void readdpwbyname (struct database_dyn *db, struct hashentry *he,
			   struct datahead *dh);
extern void readdpwbyuid (struct database_dyn *db, struct hashentry *he,
			  struct datahead *dh);

/* grpcache.c */
extern void addgrbyname (struct database_dyn *db, int fd, request_header *req,
			 void *key, uid_t uid);
extern void addgrbygid (struct database_dyn *db, int fd, request_header *req,
			void *key, uid_t uid);
extern void readdgrbyname (struct database_dyn *db, struct hashentry *he,
			   struct datahead *dh);
extern void readdgrbygid (struct database_dyn *db, struct hashentry *he,
			  struct datahead *dh);

/* hstcache.c */
extern void addhstbyname (struct database_dyn *db, int fd, request_header *req,
			  void *key, uid_t uid);
extern void addhstbyaddr (struct database_dyn *db, int fd, request_header *req,
			  void *key, uid_t uid);
extern void addhstbynamev6 (struct database_dyn *db, int fd,
			    request_header *req, void *key, uid_t uid);
extern void addhstbyaddrv6 (struct database_dyn *db, int fd,
			    request_header *req, void *key, uid_t uid);
extern void readdhstbyname (struct database_dyn *db, struct hashentry *he,
			    struct datahead *dh);
extern void readdhstbyaddr (struct database_dyn *db, struct hashentry *he,
			    struct datahead *dh);
extern void readdhstbynamev6 (struct database_dyn *db, struct hashentry *he,
			      struct datahead *dh);
extern void readdhstbyaddrv6 (struct database_dyn *db, struct hashentry *he,
			      struct datahead *dh);


/* mem.c */
extern void *mempool_alloc (struct database_dyn *db, size_t len);
extern void gc (struct database_dyn *db);

#endif /* nscd.h */