ccan/ccan/tdb2/private.h

#ifndef TDB_PRIVATE_H
#define TDB_PRIVATE_H
 /* 
   Trivial Database 2: private types and prototypes
   Copyright (C) Rusty Russell 2010

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#define _XOPEN_SOURCE 500
#define _FILE_OFFSET_BITS 64
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <utime.h>
#include <unistd.h>
#include "config.h"
#include <ccan/tdb2/tdb2.h>
#include <ccan/likely/likely.h>
#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#endif

#ifndef TEST_IT
#define TEST_IT(cond)
#endif

/* #define TDB_TRACE 1 */

#ifndef __STRING
#define __STRING(x)    #x
#endif

#ifndef __STRINGSTRING
#define __STRINGSTRING(x) __STRING(x)
#endif

#ifndef __location__
#define __location__ __FILE__ ":" __STRINGSTRING(__LINE__)
#endif

typedef uint64_t tdb_len_t;
typedef uint64_t 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 ((uint64_t)(0x26011967 + 7))
#define TDB_MAGIC ((uint64_t)0x1999)
#define TDB_FREE_MAGIC (~(uint64_t)TDB_MAGIC)
#define TDB_HASH_MAGIC (0xA1ABE11A01092008ULL)
#define TDB_RECOVERY_MAGIC (0xf53bc0e7U)
#define TDB_RECOVERY_INVALID_MAGIC (0x0)
#define TDB_EXTRA_HASHBITS (11) /* We steal 11 bits to stash hash info. */
#define TDB_EXTRA_HASHBITS_NUM (3)

#define TDB_OFF_ERR ((tdb_off_t)-1)

/* Prevent others from opening the file. */
#define TDB_OPEN_LOCK 0
/* Doing a transaction. */
#define TDB_TRANSACTION_LOCK 1
/* Hash chain locks. */
#define TDB_HASH_LOCK_START 2

/* We start wih 256 hash buckets, 10 free buckets.  A 4k-sized zone. */
#define INITIAL_HASH_BITS 8
#define INITIAL_FREE_BUCKETS 10
#define INITIAL_ZONE_BITS 12

#if !HAVE_BSWAP_64
static inline uint64_t bswap_64(uint64_t x)
{
	return (((x&0x000000FFULL)<<56)
		| ((x&0x0000FF00ULL)<<48)
		| ((x&0x00FF0000ULL)<<40)
		| ((x&0xFF000000ULL)<<32)
		| ((x>>8)&0xFF000000ULL)
		| ((x>>16)&0x00FF0000ULL)
		| ((x>>24)&0x0000FF00ULL)
		| ((x>>32)&0x000000FFULL));
}
#endif

struct tdb_used_record {
	/* For on-disk compatibility, we avoid bitfields:
	   magic: 16,        (highest)
	   key_len_bits: 5,
           hash:11,
	   extra_padding: 32 (lowest)
	*/
        uint64_t magic_and_meta;
	/* The bottom key_len_bits*2 are key length, rest is data length. */
        uint64_t key_and_data_len;
};

static inline unsigned rec_key_bits(const struct tdb_used_record *r)
{
	return ((r->magic_and_meta >> 43) & ((1 << 5)-1)) * 2;
}

static inline uint64_t rec_key_length(const struct tdb_used_record *r)
{
	return r->key_and_data_len & ((1ULL << rec_key_bits(r)) - 1);
}

static inline uint64_t rec_data_length(const struct tdb_used_record *r)
{
	return r->key_and_data_len >> rec_key_bits(r);
}

static inline uint64_t rec_extra_padding(const struct tdb_used_record *r)
{
	return r->magic_and_meta & 0xFFFFFFFF;
}

static inline uint64_t rec_hash(const struct tdb_used_record *r)
{
	return ((r->magic_and_meta >> 32) & ((1ULL << 11) - 1)) << (64 - 11);
}

static inline uint16_t rec_magic(const struct tdb_used_record *r)
{
	return (r->magic_and_meta >> 48);
}

struct tdb_free_record {
        uint64_t magic;
        uint64_t data_len; /* Not counting these two fields. */
	/* This is why the minimum record size is 16 bytes.  */
	uint64_t next, prev;
};

/* These parts can change while we have db open. */
struct tdb_header_volatile {
	uint64_t generation; /* Makes sure it changes on every update. */
	uint64_t hash_bits; /* Entries in hash table. */
	uint64_t hash_off; /* Offset of hash table. */
	uint64_t num_zones; /* How many zones in the file. */
	uint64_t zone_bits; /* Size of zones. */
	uint64_t free_buckets; /* How many buckets in each zone. */
	uint64_t free_off; /* Arrays of free entries. */
};

/* this is stored at the front of every database */
struct tdb_header {
	char magic_food[32]; /* for /etc/magic */
	uint64_t version; /* version of the code */
	uint64_t hash_test; /* result of hashing HASH_MAGIC. */
	uint64_t hash_seed; /* "random" seed written at creation time. */

	struct tdb_header_volatile v;

	tdb_off_t reserved[19];
};

enum tdb_lock_flags {
	/* WAIT == F_SETLKW, NOWAIT == F_SETLK */
	TDB_LOCK_NOWAIT = 0,
	TDB_LOCK_WAIT = 1,
	/* If set, don't log an error on failure. */
	TDB_LOCK_PROBE = 2,
};

struct tdb_lock_type {
	uint32_t off;
	uint32_t count;
	uint32_t ltype;
};

struct tdb_context {
	/* Filename of the database. */
	const char *name;

	/* Mmap (if any), or malloc (for TDB_INTERNAL). */
	void *map_ptr;

	 /* Open file descriptor (undefined for TDB_INTERNAL). */
	int fd;

	/* How much space has been mapped (<= current file size) */
	tdb_len_t map_size;

	/* Opened read-only? */
	bool read_only;

	/* Error code for last tdb error. */
	enum TDB_ERROR ecode; 

	/* A cached copy of the header */
	struct tdb_header header; 
	/* (for debugging). */
	bool header_uptodate; 

	/* the flags passed to tdb_open, for tdb_reopen. */
	uint32_t flags;

	/* Logging function */
	tdb_logfn_t log;
	void *log_priv;

	/* Hash function. */
	tdb_hashfn_t khash;
	void *hash_priv;

	/* What zone of the tdb to use, for spreading load. */
	uint64_t last_zone; 

	/* IO methods: changes for transactions. */
	const struct tdb_methods *methods;

	/* Lock information */
	struct tdb_lock_type allrecord_lock;
	uint64_t num_lockrecs;
	struct tdb_lock_type *lockrecs;

	/* Set if we are in a transaction. */
	struct tdb_transaction *transaction;
	
	/* Single list of all TDBs, to avoid multiple opens. */
	struct tdb_context *next;
	dev_t device;	
	ino_t inode;
};

struct tdb_methods {
	int (*read)(struct tdb_context *, tdb_off_t, void *, tdb_len_t);
	int (*write)(struct tdb_context *, tdb_off_t, const void *, tdb_len_t);
	int (*oob)(struct tdb_context *, tdb_off_t, bool);
	int (*expand_file)(struct tdb_context *, tdb_len_t, tdb_len_t);
};

/*
  internal prototypes
*/
/* tdb.c: */
/* Returns true if header changed. */
bool update_header(struct tdb_context *tdb);

/* Hash random memory. */
uint64_t tdb_hash(struct tdb_context *tdb, const void *ptr, size_t len);


/* free.c: */
uint64_t random_free_zone(struct tdb_context *tdb);

/* If this fails, try tdb_expand. */
tdb_off_t alloc(struct tdb_context *tdb, size_t keylen, size_t datalen,
		uint64_t hash, bool growing);

/* Put this record in a free list. */
int add_free_record(struct tdb_context *tdb,
		    tdb_off_t off, tdb_len_t len_with_header);

/* Set up header for a used record. */
int set_header(struct tdb_context *tdb,
	       struct tdb_used_record *rec,
	       uint64_t keylen, uint64_t datalen,
	       uint64_t actuallen, uint64_t hash);

/* Used by tdb_check to verify. */
unsigned int size_to_bucket(struct tdb_context *tdb, tdb_len_t data_len);
tdb_off_t zone_of(struct tdb_context *tdb, tdb_off_t off);

/* io.c: */
/* Initialize tdb->methods. */
void tdb_io_init(struct tdb_context *tdb);

/* Convert endian of the buffer if required. */
void *tdb_convert(const struct tdb_context *tdb, void *buf, tdb_len_t size);

/* Unmap and try to map the tdb. */
void tdb_munmap(struct tdb_context *tdb);
void tdb_mmap(struct tdb_context *tdb);

/* Hand data to a function, direct if possible */
int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
		   tdb_off_t offset, tdb_len_t len,
		   int (*parser)(TDB_DATA key, TDB_DATA data,
				 void *private_data),
		   void *private_data);

/* Either make a copy into pad and return that, or return ptr into mmap.
 * Converts endian (ie. will use pad in that case). */
void *tdb_get(struct tdb_context *tdb, tdb_off_t off, void *pad, size_t len);

/* Either alloc a copy, or give direct access.  Release frees or noop. */
const void *tdb_access_read(struct tdb_context *tdb,
			    tdb_off_t off, tdb_len_t len);
void tdb_access_release(struct tdb_context *tdb, const void *p);

/* Convenience routine to get an offset. */
tdb_off_t tdb_read_off(struct tdb_context *tdb, tdb_off_t off);

/* Write an offset at an offset. */
int tdb_write_off(struct tdb_context *tdb, tdb_off_t off, tdb_off_t val);

/* Clear an ondisk area. */
int zero_out(struct tdb_context *tdb, tdb_off_t off, tdb_len_t len);

/* Return a non-zero offset in this array, or num. */
tdb_off_t tdb_find_nonzero_off(struct tdb_context *tdb, tdb_off_t off,
			       uint64_t num);

/* Return a zero offset in this array, or num. */
tdb_off_t tdb_find_zero_off(struct tdb_context *tdb, tdb_off_t off,
			    uint64_t num);

/* Even on files, we can get partial writes due to signals. */
bool tdb_pwrite_all(int fd, const void *buf, size_t len, tdb_off_t off);
bool tdb_pread_all(int fd, void *buf, size_t len, tdb_off_t off);
bool tdb_read_all(int fd, void *buf, size_t len);

/* Allocate and make a copy of some offset. */
void *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);

/* Munges record and writes it */
int tdb_write_convert(struct tdb_context *tdb, tdb_off_t off,
		      void *rec, size_t len);

/* Reads record and converts it */
int tdb_read_convert(struct tdb_context *tdb, tdb_off_t off,
		     void *rec, size_t len);

/* Hash on disk. */
uint64_t hash_record(struct tdb_context *tdb, tdb_off_t off);

/* lock.c: */
/* Lock/unlock a particular hash list. */
int tdb_lock_list(struct tdb_context *tdb, tdb_off_t list,
		  int ltype, enum tdb_lock_flags waitflag);
int tdb_unlock_list(struct tdb_context *tdb, tdb_off_t list, int ltype);

/* Lock/unlock a particular free list. */
int tdb_lock_free_list(struct tdb_context *tdb, tdb_off_t flist,
		       enum tdb_lock_flags waitflag);
void tdb_unlock_free_list(struct tdb_context *tdb, tdb_off_t flist);

/* Do we have any locks? */
bool tdb_has_locks(struct tdb_context *tdb);

/* Lock entire database. */
int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
		       enum tdb_lock_flags flags, bool upgradable);
int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype);

/* Serialize db open. */
int tdb_lock_open(struct tdb_context *tdb);
void tdb_unlock_open(struct tdb_context *tdb);
/* Expand the file. */
int tdb_expand(struct tdb_context *tdb, tdb_len_t klen, tdb_len_t dlen,
	       bool growing);

#if 0
/* Low-level locking primitives. */
int tdb_nest_lock(struct tdb_context *tdb, tdb_off_t offset, int ltype,
		  enum tdb_lock_flags flags);
int tdb_nest_unlock(struct tdb_context *tdb, tdb_off_t offset, int ltype);

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_lock_nonblock(struct tdb_context *tdb, int list, int ltype);
bool tdb_have_locks(struct tdb_context *tdb);
int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
int tdb_brlock(struct tdb_context *tdb,
	       int rw_type, tdb_off_t offset, size_t len,
	       enum tdb_lock_flags flags);
int tdb_brunlock(struct tdb_context *tdb,
		 int rw_type, tdb_off_t offset, size_t len);
bool tdb_have_extra_locks(struct tdb_context *tdb);
void tdb_release_extra_locks(struct tdb_context *tdb);
int tdb_transaction_lock(struct tdb_context *tdb, int ltype);
int tdb_transaction_unlock(struct tdb_context *tdb, int ltype);
int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
		       enum tdb_lock_flags flags, bool upgradable);
int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype);
int tdb_allrecord_upgrade(struct tdb_context *tdb);
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);
int tdb_free(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct tdb_record *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);
bool tdb_needs_recovery(struct tdb_context *tdb);
int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct tdb_record *rec);
unsigned char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);
int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
		   tdb_off_t offset, tdb_len_t len,
		   int (*parser)(TDB_DATA key, TDB_DATA data,
				 void *private_data),
		   void *private_data);
tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t hash, int locktype,
			   struct tdb_record *rec);
void tdb_io_init(struct tdb_context *tdb);
int tdb_expand(struct tdb_context *tdb, tdb_off_t size);
int tdb_rec_free_read(struct tdb_context *tdb, tdb_off_t off,
		      struct tdb_record *rec);
#endif

#ifdef TDB_TRACE
void tdb_trace(struct tdb_context *tdb, const char *op);
void tdb_trace_seqnum(struct tdb_context *tdb, uint32_t seqnum, const char *op);
void tdb_trace_open(struct tdb_context *tdb, const char *op,
		    unsigned hash_size, unsigned tdb_flags, unsigned open_flags);
void tdb_trace_ret(struct tdb_context *tdb, const char *op, int ret);
void tdb_trace_retrec(struct tdb_context *tdb, const char *op, TDB_DATA ret);
void tdb_trace_1rec(struct tdb_context *tdb, const char *op,
		    TDB_DATA rec);
void tdb_trace_1rec_ret(struct tdb_context *tdb, const char *op,
			TDB_DATA rec, int ret);
void tdb_trace_1rec_retrec(struct tdb_context *tdb, const char *op,
			   TDB_DATA rec, TDB_DATA ret);
void tdb_trace_2rec_flag_ret(struct tdb_context *tdb, const char *op,
			     TDB_DATA rec1, TDB_DATA rec2, unsigned flag,
			     int ret);
void tdb_trace_2rec_retrec(struct tdb_context *tdb, const char *op,
			   TDB_DATA rec1, TDB_DATA rec2, TDB_DATA ret);
#else
#define tdb_trace(tdb, op)
#define tdb_trace_seqnum(tdb, seqnum, op)
#define tdb_trace_open(tdb, op, hash_size, tdb_flags, open_flags)
#define tdb_trace_ret(tdb, op, ret)
#define tdb_trace_retrec(tdb, op, ret)
#define tdb_trace_1rec(tdb, op, rec)
#define tdb_trace_1rec_ret(tdb, op, rec, ret)
#define tdb_trace_1rec_retrec(tdb, op, rec, ret)
#define tdb_trace_2rec_flag_ret(tdb, op, rec1, rec2, flag, ret)
#define tdb_trace_2rec_retrec(tdb, op, rec1, rec2, ret)
#endif /* !TDB_TRACE */

#endif