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/*
Unix SMB/CIFS implementation.
trivial database library - private includes
Copyright (C) Andrew Tridgell 2005
** NOTE! The following LGPL license applies to the tdb
** library. This does NOT imply that all of Samba is released
** under the LGPL
This 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 of the License, or (at your option) any later version.
This 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 this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "replace.h"
#include "system/filesys.h"
#include "system/time.h"
#include "system/shmem.h"
#include "system/select.h"
#include "tdb.h"
#ifndef u32
#define u32 unsigned
#endif
#ifndef HAVE_GETPAGESIZE
#define getpagesize() 0x2000
#endif
typedef u32 tdb_len_t;
typedef u32 tdb_off_t;
#ifndef offsetof
#define offsetof(t,f) ((unsigned int)&((t *)0)->f)
#endif
#define TDB_MAGIC_FOOD "TDB file\n"
#define TDB_VERSION (0x26011967 + 6)
#define TDB_MAGIC (0x26011999U)
#define TDB_FREE_MAGIC (~TDB_MAGIC)
#define TDB_DEAD_MAGIC (0xFEE1DEAD)
#define TDB_RECOVERY_MAGIC (0xf53bc0e7U)
#define TDB_ALIGNMENT 4
#define MIN_REC_SIZE (2*sizeof(struct list_struct) + TDB_ALIGNMENT)
#define DEFAULT_HASH_SIZE 131
#define FREELIST_TOP (sizeof(struct tdb_header))
#define TDB_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1))
#define TDB_BYTEREV(x) (((((x)&0xff)<<24)|((x)&0xFF00)<<8)|(((x)>>8)&0xFF00)|((x)>>24))
#define TDB_DEAD(r) ((r)->magic == TDB_DEAD_MAGIC)
#define TDB_BAD_MAGIC(r) ((r)->magic != TDB_MAGIC && !TDB_DEAD(r))
#define TDB_HASH_TOP(hash) (FREELIST_TOP + (BUCKET(hash)+1)*sizeof(tdb_off_t))
#define TDB_HASHTABLE_SIZE(tdb) ((tdb->header.hash_size+1)*sizeof(tdb_off_t))
#define TDB_DATA_START(hash_size) TDB_HASH_TOP(hash_size-1)
#define TDB_RECOVERY_HEAD offsetof(struct tdb_header, recovery_start)
#define TDB_SEQNUM_OFS offsetof(struct tdb_header, sequence_number)
#define TDB_PAD_BYTE 0x42
#define TDB_PAD_U32 0x42424242
/* NB assumes there is a local variable called "tdb" that is the
* current context, also takes doubly-parenthesized print-style
* argument. */
#define TDB_LOG(x) tdb->log.log_fn x
/* lock offsets */
#define GLOBAL_LOCK 0
#define ACTIVE_LOCK 4
#define TRANSACTION_LOCK 8
/* free memory if the pointer is valid and zero the pointer */
#ifndef SAFE_FREE
#define SAFE_FREE(x) do { if ((x) != NULL) {free(x); (x)=NULL;} } while(0)
#endif
#define BUCKET(hash) ((hash) % tdb->header.hash_size)
#define DOCONV() (tdb->flags & TDB_CONVERT)
#define CONVERT(x) (DOCONV() ? tdb_convert(&x, sizeof(x)) : &x)
/* the body of the database is made of one list_struct for the free space
plus a separate data list for each hash value */
struct list_struct {
tdb_off_t next; /* offset of the next record in the list */
tdb_len_t rec_len; /* total byte length of record */
tdb_len_t key_len; /* byte length of key */
tdb_len_t data_len; /* byte length of data */
u32 full_hash; /* the full 32 bit hash of the key */
u32 magic; /* try to catch errors */
/* the following union is implied:
union {
char record[rec_len];
struct {
char key[key_len];
char data[data_len];
}
u32 totalsize; (tailer)
}
*/
};
/* this is stored at the front of every database */
struct tdb_header {
char magic_food[32]; /* for /etc/magic */
u32 version; /* version of the code */
u32 hash_size; /* number of hash entries */
tdb_off_t rwlocks; /* obsolete - kept to detect old formats */
tdb_off_t recovery_start; /* offset of transaction recovery region */
tdb_off_t sequence_number; /* used when TDB_SEQNUM is set */
tdb_off_t reserved[29];
};
struct tdb_lock_type {
u32 count;
u32 ltype;
};
struct tdb_traverse_lock {
struct tdb_traverse_lock *next;
u32 off;
u32 hash;
int lock_rw;
};
struct tdb_methods {
int (*tdb_read)(struct tdb_context *, tdb_off_t , void *, tdb_len_t , int );
int (*tdb_write)(struct tdb_context *, tdb_off_t, const void *, tdb_len_t);
void (*next_hash_chain)(struct tdb_context *, u32 *);
int (*tdb_oob)(struct tdb_context *, tdb_off_t , int );
int (*tdb_expand_file)(struct tdb_context *, tdb_off_t , tdb_off_t );
int (*tdb_brlock)(struct tdb_context *, tdb_off_t , int, int, int, size_t);
};
struct tdb_context {
char *name; /* the name of the database */
void *map_ptr; /* where it is currently mapped */
int fd; /* open file descriptor for the database */
tdb_len_t map_size; /* how much space has been mapped */
int read_only; /* opened read-only */
int traverse_read; /* read-only traversal */
struct tdb_lock_type global_lock;
struct tdb_lock_type *locked; /* array of chain locks */
enum TDB_ERROR ecode; /* error code for last tdb error */
struct tdb_header header; /* a cached copy of the header */
u32 flags; /* the flags passed to tdb_open */
struct tdb_traverse_lock travlocks; /* current traversal locks */
struct tdb_context *next; /* all tdbs to avoid multiple opens */
dev_t device; /* uniquely identifies this tdb */
ino_t inode; /* uniquely identifies this tdb */
struct tdb_logging_context log;
unsigned int (*hash_fn)(TDB_DATA *key);
int open_flags; /* flags used in the open - needed by reopen */
unsigned int num_locks; /* number of chain locks held */
const struct tdb_methods *methods;
struct tdb_transaction *transaction;
int page_size;
};
/*
internal prototypes
*/
int tdb_munmap(struct tdb_context *tdb);
void tdb_mmap(struct tdb_context *tdb);
int tdb_lock(struct tdb_context *tdb, int list, int ltype);
int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe, size_t len);
int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);
int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off);
int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
void *tdb_convert(void *buf, u32 size);
int tdb_free(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct list_struct *rec);
int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off);
int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off);
int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct list_struct *rec);
char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);
tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash, int locktype,
struct list_struct *rec);
void tdb_io_init(struct tdb_context *tdb);
int tdb_expand(struct tdb_context *tdb, tdb_off_t size);
int rec_free_read(struct tdb_context *tdb, tdb_off_t off,
struct list_struct *rec);
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