source/tdb/common/tdb_private.h

   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
  42 typedef u32 tdb_len_t;
  43 typedef 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 */
  94 struct 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 */
 115 struct 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
 125 struct tdb_lock_type {
 126         int list;
 127         u32 count;
 128         u32 ltype;
 129 };
 130
 131 struct tdb_traverse_lock {
 132         struct tdb_traverse_lock *next;
 133         u32 off;
 134         u32 hash;
 135         int lock_rw;
 136 };
 137
 138
 139 struct 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
 148 struct 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 */
 179 int tdb_munmap(struct tdb_context *tdb);
 180 void tdb_mmap(struct tdb_context *tdb);
 181 int tdb_lock(struct tdb_context *tdb, int list, int ltype);
 182 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
 183 int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe, size_t len);
 184 int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);
 185 int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
 186 int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off);
 187 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 188 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 189 void *tdb_convert(void *buf, u32 size);
 190 int tdb_free(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
 191 tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct list_struct *rec);
 192 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 193 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 194 int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off);
 195 int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off);
 196 int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
 197 int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
 198 int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct list_struct *rec);
 199 char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);
 200 int 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);
 205 tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash, int locktype,
 206                            struct list_struct *rec);
 207 void tdb_io_init(struct tdb_context *tdb);
 208 int tdb_expand(struct tdb_context *tdb, tdb_off_t size);
 209 int rec_free_read(struct tdb_context *tdb, tdb_off_t off,
 210                   struct list_struct *rec);
 211
 212