1 /* 2 Unix SMB/CIFS implementation. 3 4 trivial database library - private includes 5 6 Copyright (C) Andrew Tridgell 2005 7 8 ** NOTE! The following LGPL license applies to the tdb 9 ** library. This does NOT imply that all of Samba is released 10 ** under the LGPL 11 12 This library is free software; you can redistribute it and/or 13 modify it under the terms of the GNU Lesser General Public 14 License as published by the Free Software Foundation; either 15 version 2 of the License, or (at your option) any later version. 16 17 This library is distributed in the hope that it will be useful, 18 but WITHOUT ANY WARRANTY; without even the implied warranty of 19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 Lesser General Public License for more details. 21 22 You should have received a copy of the GNU Lesser General Public 23 License along with this library; if not, write to the Free Software 24 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 25*/ 26 27#include "replace.h" 28#include "system/filesys.h" 29#include "system/time.h" 30#include "system/shmem.h" 31#include "system/select.h" 32#include "tdb.h" 33 34#ifndef u32 35#define u32 unsigned 36#endif 37 38#ifndef HAVE_GETPAGESIZE 39#define getpagesize() 0x2000 40#endif 41 42typedef u32 tdb_len_t; 43typedef u32 tdb_off_t; 44 45#ifndef offsetof 46#define offsetof(t,f) ((unsigned int)&((t *)0)->f) 47#endif 48 49#define TDB_MAGIC_FOOD "TDB file\n" 50#define TDB_VERSION (0x26011967 + 6) 51#define TDB_MAGIC (0x26011999U) 52#define TDB_FREE_MAGIC (~TDB_MAGIC) 53#define TDB_DEAD_MAGIC (0xFEE1DEAD) 54#define TDB_RECOVERY_MAGIC (0xf53bc0e7U) 55#define TDB_ALIGNMENT 4 56#define MIN_REC_SIZE (2*sizeof(struct list_struct) + TDB_ALIGNMENT) 57#define DEFAULT_HASH_SIZE 131 58#define FREELIST_TOP (sizeof(struct tdb_header)) 59#define TDB_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1)) 60#define TDB_BYTEREV(x) (((((x)&0xff)<<24)|((x)&0xFF00)<<8)|(((x)>>8)&0xFF00)|((x)>>24)) 61#define TDB_DEAD(r) ((r)->magic == TDB_DEAD_MAGIC) 62#define TDB_BAD_MAGIC(r) ((r)->magic != TDB_MAGIC && !TDB_DEAD(r)) 63#define TDB_HASH_TOP(hash) (FREELIST_TOP + (BUCKET(hash)+1)*sizeof(tdb_off_t)) 64#define TDB_HASHTABLE_SIZE(tdb) ((tdb->header.hash_size+1)*sizeof(tdb_off_t)) 65#define TDB_DATA_START(hash_size) TDB_HASH_TOP(hash_size-1) 66#define TDB_RECOVERY_HEAD offsetof(struct tdb_header, recovery_start) 67#define TDB_SEQNUM_OFS offsetof(struct tdb_header, sequence_number) 68#define TDB_PAD_BYTE 0x42 69#define TDB_PAD_U32 0x42424242 70 71/* NB assumes there is a local variable called "tdb" that is the 72 * current context, also takes doubly-parenthesized print-style 73 * argument. */ 74#define TDB_LOG(x) tdb->log.log_fn x 75 76/* lock offsets */ 77#define GLOBAL_LOCK 0 78#define ACTIVE_LOCK 4 79#define TRANSACTION_LOCK 8 80 81/* free memory if the pointer is valid and zero the pointer */ 82#ifndef SAFE_FREE 83#define SAFE_FREE(x) do { if ((x) != NULL) {free(x); (x)=NULL;} } while(0) 84#endif 85 86#define BUCKET(hash) ((hash) % tdb->header.hash_size) 87 88#define DOCONV() (tdb->flags & TDB_CONVERT) 89#define CONVERT(x) (DOCONV() ? tdb_convert(&x, sizeof(x)) : &x) 90 91 92/* the body of the database is made of one list_struct for the free space 93 plus a separate data list for each hash value */ 94struct list_struct { 95 tdb_off_t next; /* offset of the next record in the list */ 96 tdb_len_t rec_len; /* total byte length of record */ 97 tdb_len_t key_len; /* byte length of key */ 98 tdb_len_t data_len; /* byte length of data */ 99 u32 full_hash; /* the full 32 bit hash of the key */ 100 u32 magic; /* try to catch errors */ 101 /* the following union is implied: 102 union { 103 char record[rec_len]; 104 struct { 105 char key[key_len]; 106 char data[data_len]; 107 } 108 u32 totalsize; (tailer) 109 } 110 */ 111}; 112 113 114/* this is stored at the front of every database */ 115struct tdb_header { 116 char magic_food[32]; /* for /etc/magic */ 117 u32 version; /* version of the code */ 118 u32 hash_size; /* number of hash entries */ 119 tdb_off_t rwlocks; /* obsolete - kept to detect old formats */ 120 tdb_off_t recovery_start; /* offset of transaction recovery region */ 121 tdb_off_t sequence_number; /* used when TDB_SEQNUM is set */ 122 tdb_off_t reserved[29]; 123}; 124 125struct tdb_lock_type { 126 int list; 127 u32 count; 128 u32 ltype; 129}; 130 131struct tdb_traverse_lock { 132 struct tdb_traverse_lock *next; 133 u32 off; 134 u32 hash; 135 int lock_rw; 136}; 137 138 139struct tdb_methods { 140 int (*tdb_read)(struct tdb_context *, tdb_off_t , void *, tdb_len_t , int ); 141 int (*tdb_write)(struct tdb_context *, tdb_off_t, const void *, tdb_len_t); 142 void (*next_hash_chain)(struct tdb_context *, u32 *); 143 int (*tdb_oob)(struct tdb_context *, tdb_off_t , int ); 144 int (*tdb_expand_file)(struct tdb_context *, tdb_off_t , tdb_off_t ); 145 int (*tdb_brlock)(struct tdb_context *, tdb_off_t , int, int, int, size_t); 146}; 147 148struct tdb_context { 149 char *name; /* the name of the database */ 150 void *map_ptr; /* where it is currently mapped */ 151 int fd; /* open file descriptor for the database */ 152 tdb_len_t map_size; /* how much space has been mapped */ 153 int read_only; /* opened read-only */ 154 int traverse_read; /* read-only traversal */ 155 struct tdb_lock_type global_lock; 156 int num_lockrecs; 157 struct tdb_lock_type *lockrecs; /* only real locks, all with count>0 */ 158 enum TDB_ERROR ecode; /* error code for last tdb error */ 159 struct tdb_header header; /* a cached copy of the header */ 160 u32 flags; /* the flags passed to tdb_open */ 161 struct tdb_traverse_lock travlocks; /* current traversal locks */ 162 struct tdb_context *next; /* all tdbs to avoid multiple opens */ 163 dev_t device; /* uniquely identifies this tdb */ 164 ino_t inode; /* uniquely identifies this tdb */ 165 struct tdb_logging_context log; 166 unsigned int (*hash_fn)(TDB_DATA *key); 167 int open_flags; /* flags used in the open - needed by reopen */ 168 unsigned int num_locks; /* number of chain locks held */ 169 const struct tdb_methods *methods; 170 struct tdb_transaction *transaction; 171 int page_size; 172 int max_dead_records; 173}; 174 175 176/* 177 internal prototypes 178*/ 179int tdb_munmap(struct tdb_context *tdb); 180void tdb_mmap(struct tdb_context *tdb); 181int tdb_lock(struct tdb_context *tdb, int list, int ltype); 182int tdb_unlock(struct tdb_context *tdb, int list, int ltype); 183int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe, size_t len); 184int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len); 185int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off); 186int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off); 187int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d); 188int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d); 189void *tdb_convert(void *buf, u32 size); 190int tdb_free(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec); 191tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct list_struct *rec); 192int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d); 193int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d); 194int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off); 195int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off); 196int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec); 197int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec); 198int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct list_struct *rec); 199char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len); 200int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key, 201 tdb_off_t offset, tdb_len_t len, 202 int (*parser)(TDB_DATA key, TDB_DATA data, 203 void *private_data), 204 void *private_data); 205tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash, int locktype, 206 struct list_struct *rec); 207void tdb_io_init(struct tdb_context *tdb); 208int tdb_expand(struct tdb_context *tdb, tdb_off_t size); 209int rec_free_read(struct tdb_context *tdb, tdb_off_t off, 210 struct list_struct *rec); 211 212 213