root/lib/tdb/common/tdb_private.h

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INCLUDED FROM


   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 3 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, see <http://www.gnu.org/licenses/>.
  24 */
  25 
  26 #include "replace.h"
  27 #include "system/filesys.h"
  28 #include "system/time.h"
  29 #include "system/shmem.h"
  30 #include "system/select.h"
  31 #include "system/wait.h"
  32 #include "tdb.h"
  33 
  34 #ifndef HAVE_GETPAGESIZE
  35 #define getpagesize() 0x2000
  36 #endif
  37 
  38 typedef uint32_t tdb_len_t;
  39 typedef uint32_t tdb_off_t;
  40 
  41 #ifndef offsetof
  42 #define offsetof(t,f) ((unsigned int)&((t *)0)->f)
  43 #endif
  44 
  45 #define TDB_MAGIC_FOOD "TDB file\n"
  46 #define TDB_VERSION (0x26011967 + 6)
  47 #define TDB_MAGIC (0x26011999U)
  48 #define TDB_FREE_MAGIC (~TDB_MAGIC)
  49 #define TDB_DEAD_MAGIC (0xFEE1DEAD)
  50 #define TDB_RECOVERY_MAGIC (0xf53bc0e7U)
  51 #define TDB_ALIGNMENT 4
  52 #define DEFAULT_HASH_SIZE 131
  53 #define FREELIST_TOP (sizeof(struct tdb_header))
  54 #define TDB_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1))
  55 #define TDB_BYTEREV(x) (((((x)&0xff)<<24)|((x)&0xFF00)<<8)|(((x)>>8)&0xFF00)|((x)>>24))
  56 #define TDB_DEAD(r) ((r)->magic == TDB_DEAD_MAGIC)
  57 #define TDB_BAD_MAGIC(r) ((r)->magic != TDB_MAGIC && !TDB_DEAD(r))
  58 #define TDB_HASH_TOP(hash) (FREELIST_TOP + (BUCKET(hash)+1)*sizeof(tdb_off_t))
  59 #define TDB_HASHTABLE_SIZE(tdb) ((tdb->header.hash_size+1)*sizeof(tdb_off_t))
  60 #define TDB_DATA_START(hash_size) (TDB_HASH_TOP(hash_size-1) + sizeof(tdb_off_t))
  61 #define TDB_RECOVERY_HEAD offsetof(struct tdb_header, recovery_start)
  62 #define TDB_SEQNUM_OFS    offsetof(struct tdb_header, sequence_number)
  63 #define TDB_PAD_BYTE 0x42
  64 #define TDB_PAD_U32  0x42424242
  65 
  66 /* NB assumes there is a local variable called "tdb" that is the
  67  * current context, also takes doubly-parenthesized print-style
  68  * argument. */
  69 #define TDB_LOG(x) tdb->log.log_fn x
  70 
  71 /* lock offsets */
  72 #define GLOBAL_LOCK      0
  73 #define ACTIVE_LOCK      4
  74 #define TRANSACTION_LOCK 8
  75 
  76 /* free memory if the pointer is valid and zero the pointer */
  77 #ifndef SAFE_FREE
  78 #define SAFE_FREE(x) do { if ((x) != NULL) {free(x); (x)=NULL;} } while(0)
  79 #endif
  80 
  81 #define BUCKET(hash) ((hash) % tdb->header.hash_size)
  82 
  83 #define DOCONV() (tdb->flags & TDB_CONVERT)
  84 #define CONVERT(x) (DOCONV() ? tdb_convert(&x, sizeof(x)) : &x)
  85 
  86 
  87 /* the body of the database is made of one list_struct for the free space
  88    plus a separate data list for each hash value */
  89 struct list_struct {
  90         tdb_off_t next; /* offset of the next record in the list */
  91         tdb_len_t rec_len; /* total byte length of record */
  92         tdb_len_t key_len; /* byte length of key */
  93         tdb_len_t data_len; /* byte length of data */
  94         uint32_t full_hash; /* the full 32 bit hash of the key */
  95         uint32_t magic;   /* try to catch errors */
  96         /* the following union is implied:
  97                 union {
  98                         char record[rec_len];
  99                         struct {
 100                                 char key[key_len];
 101                                 char data[data_len];
 102                         }
 103                         uint32_t totalsize; (tailer)
 104                 }
 105         */
 106 };
 107 
 108 
 109 /* this is stored at the front of every database */
 110 struct tdb_header {
 111         char magic_food[32]; /* for /etc/magic */
 112         uint32_t version; /* version of the code */
 113         uint32_t hash_size; /* number of hash entries */
 114         tdb_off_t rwlocks; /* obsolete - kept to detect old formats */
 115         tdb_off_t recovery_start; /* offset of transaction recovery region */
 116         tdb_off_t sequence_number; /* used when TDB_SEQNUM is set */
 117         tdb_off_t reserved[29];
 118 };
 119 
 120 struct tdb_lock_type {
 121         int list;
 122         uint32_t count;
 123         uint32_t ltype;
 124 };
 125 
 126 struct tdb_traverse_lock {
 127         struct tdb_traverse_lock *next;
 128         uint32_t off;
 129         uint32_t hash;
 130         int lock_rw;
 131 };
 132 
 133 
 134 struct tdb_methods {
 135         int (*tdb_read)(struct tdb_context *, tdb_off_t , void *, tdb_len_t , int );
 136         int (*tdb_write)(struct tdb_context *, tdb_off_t, const void *, tdb_len_t);
 137         void (*next_hash_chain)(struct tdb_context *, uint32_t *);
 138         int (*tdb_oob)(struct tdb_context *, tdb_off_t , int );
 139         int (*tdb_expand_file)(struct tdb_context *, tdb_off_t , tdb_off_t );
 140         int (*tdb_brlock)(struct tdb_context *, tdb_off_t , int, int, int, size_t);
 141 };
 142 
 143 struct tdb_context {
 144         char *name; /* the name of the database */
 145         void *map_ptr; /* where it is currently mapped */
 146         int fd; /* open file descriptor for the database */
 147         tdb_len_t map_size; /* how much space has been mapped */
 148         int read_only; /* opened read-only */
 149         int traverse_read; /* read-only traversal */
 150         int traverse_write; /* read-write traversal */
 151         struct tdb_lock_type global_lock;
 152         int num_lockrecs;
 153         struct tdb_lock_type *lockrecs; /* only real locks, all with count>0 */
 154         enum TDB_ERROR ecode; /* error code for last tdb error */
 155         struct tdb_header header; /* a cached copy of the header */
 156         uint32_t flags; /* the flags passed to tdb_open */
 157         struct tdb_traverse_lock travlocks; /* current traversal locks */
 158         struct tdb_context *next; /* all tdbs to avoid multiple opens */
 159         dev_t device;   /* uniquely identifies this tdb */
 160         ino_t inode;    /* uniquely identifies this tdb */
 161         struct tdb_logging_context log;
 162         unsigned int (*hash_fn)(TDB_DATA *key);
 163         int open_flags; /* flags used in the open - needed by reopen */
 164         unsigned int num_locks; /* number of chain locks held */
 165         const struct tdb_methods *methods;
 166         struct tdb_transaction *transaction;
 167         int page_size;
 168         int max_dead_records;
 169         bool have_transaction_lock;
 170         volatile sig_atomic_t *interrupt_sig_ptr;
 171 };
 172 
 173 
 174 /*
 175   internal prototypes
 176 */
 177 int tdb_munmap(struct tdb_context *tdb);
 178 void tdb_mmap(struct tdb_context *tdb);
 179 int tdb_lock(struct tdb_context *tdb, int list, int ltype);
 180 int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype);
 181 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
 182 int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset, int rw_type, int lck_type, int probe, size_t len);
 183 int tdb_transaction_lock(struct tdb_context *tdb, int ltype);
 184 int tdb_transaction_unlock(struct tdb_context *tdb);
 185 int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len);
 186 int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
 187 int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off);
 188 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 189 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 190 void *tdb_convert(void *buf, uint32_t size);
 191 int tdb_free(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
 192 tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct list_struct *rec);
 193 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 194 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 195 int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off);
 196 int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off);
 197 int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
 198 int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec);
 199 int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct list_struct *rec);
 200 unsigned char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);
 201 int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
 202                    tdb_off_t offset, tdb_len_t len,
 203                    int (*parser)(TDB_DATA key, TDB_DATA data,
 204                                  void *private_data),
 205                    void *private_data);
 206 tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t hash, int locktype,
 207                            struct list_struct *rec);
 208 void tdb_io_init(struct tdb_context *tdb);
 209 int tdb_expand(struct tdb_context *tdb, tdb_off_t size);
 210 int tdb_rec_free_read(struct tdb_context *tdb, tdb_off_t off,
 211                       struct list_struct *rec);
 212 
 213 

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