lib/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 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 /* #define TDB_TRACE 1 */
  35 #ifndef HAVE_GETPAGESIZE
  36 #define getpagesize() 0x2000
  37 #endif
  38
  39 typedef uint32_t tdb_len_t;
  40 typedef uint32_t tdb_off_t;
  41
  42 #ifndef offsetof
  43 #define offsetof(t,f) ((unsigned int)&((t *)0)->f)
  44 #endif
  45
  46 #define TDB_MAGIC_FOOD "TDB file\n"
  47 #define TDB_VERSION (0x26011967 + 6)
  48 #define TDB_MAGIC (0x26011999U)
  49 #define TDB_FREE_MAGIC (~TDB_MAGIC)
  50 #define TDB_DEAD_MAGIC (0xFEE1DEAD)
  51 #define TDB_RECOVERY_MAGIC (0xf53bc0e7U)
  52 #define TDB_RECOVERY_INVALID_MAGIC (0x0)
  53 #define TDB_ALIGNMENT 4
  54 #define DEFAULT_HASH_SIZE 131
  55 #define FREELIST_TOP (sizeof(struct tdb_header))
  56 #define TDB_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1))
  57 #define TDB_BYTEREV(x) (((((x)&0xff)<<24)|((x)&0xFF00)<<8)|(((x)>>8)&0xFF00)|((x)>>24))
  58 #define TDB_DEAD(r) ((r)->magic == TDB_DEAD_MAGIC)
  59 #define TDB_BAD_MAGIC(r) ((r)->magic != TDB_MAGIC && !TDB_DEAD(r))
  60 #define TDB_HASH_TOP(hash) (FREELIST_TOP + (BUCKET(hash)+1)*sizeof(tdb_off_t))
  61 #define TDB_HASHTABLE_SIZE(tdb) ((tdb->header.hash_size+1)*sizeof(tdb_off_t))
  62 #define TDB_DATA_START(hash_size) (TDB_HASH_TOP(hash_size-1) + sizeof(tdb_off_t))
  63 #define TDB_RECOVERY_HEAD offsetof(struct tdb_header, recovery_start)
  64 #define TDB_SEQNUM_OFS    offsetof(struct tdb_header, sequence_number)
  65 #define TDB_PAD_BYTE 0x42
  66 #define TDB_PAD_U32  0x42424242
  67
  68 /* NB assumes there is a local variable called "tdb" that is the
  69  * current context, also takes doubly-parenthesized print-style
  70  * argument. */
  71 #define TDB_LOG(x) tdb->log.log_fn x
  72
  73 #ifdef TDB_TRACE
  74 void tdb_trace(struct tdb_context *tdb, const char *op);
  75 void tdb_trace_seqnum(struct tdb_context *tdb, uint32_t seqnum, const char *op);
  76 void tdb_trace_open(struct tdb_context *tdb, const char *op,
  77                     unsigned hash_size, unsigned tdb_flags, unsigned open_flags);
  78 void tdb_trace_ret(struct tdb_context *tdb, const char *op, int ret);
  79 void tdb_trace_retrec(struct tdb_context *tdb, const char *op, TDB_DATA ret);
  80 void tdb_trace_1rec(struct tdb_context *tdb, const char *op,
  81                     TDB_DATA rec);
  82 void tdb_trace_1rec_ret(struct tdb_context *tdb, const char *op,
  83                         TDB_DATA rec, int ret);
  84 void tdb_trace_1rec_retrec(struct tdb_context *tdb, const char *op,
  85                            TDB_DATA rec, TDB_DATA ret);
  86 void tdb_trace_2rec_flag_ret(struct tdb_context *tdb, const char *op,
  87                              TDB_DATA rec1, TDB_DATA rec2, unsigned flag,
  88                              int ret);
  89 void tdb_trace_2rec_retrec(struct tdb_context *tdb, const char *op,
  90                            TDB_DATA rec1, TDB_DATA rec2, TDB_DATA ret);
  91 #else
  92 #define tdb_trace(tdb, op)
  93 #define tdb_trace_seqnum(tdb, seqnum, op)
  94 #define tdb_trace_open(tdb, op, hash_size, tdb_flags, open_flags)
  95 #define tdb_trace_ret(tdb, op, ret)
  96 #define tdb_trace_retrec(tdb, op, ret)
  97 #define tdb_trace_1rec(tdb, op, rec)
  98 #define tdb_trace_1rec_ret(tdb, op, rec, ret)
  99 #define tdb_trace_1rec_retrec(tdb, op, rec, ret)
 100 #define tdb_trace_2rec_flag_ret(tdb, op, rec1, rec2, flag, ret)
 101 #define tdb_trace_2rec_retrec(tdb, op, rec1, rec2, ret)
 102 #endif /* !TDB_TRACE */
 103
 104 /* lock offsets */
 105 #define OPEN_LOCK        0
 106 #define ACTIVE_LOCK      4
 107 #define TRANSACTION_LOCK 8
 108
 109 /* free memory if the pointer is valid and zero the pointer */
 110 #ifndef SAFE_FREE
 111 #define SAFE_FREE(x) do { if ((x) != NULL) {free(x); (x)=NULL;} } while(0)
 112 #endif
 113
 114 #define BUCKET(hash) ((hash) % tdb->header.hash_size)
 115
 116 #define DOCONV() (tdb->flags & TDB_CONVERT)
 117 #define CONVERT(x) (DOCONV() ? tdb_convert(&x, sizeof(x)) : &x)
 118
 119
 120 /* the body of the database is made of one tdb_record for the free space
 121    plus a separate data list for each hash value */
 122 struct tdb_record {
 123         tdb_off_t next; /* offset of the next record in the list */
 124         tdb_len_t rec_len; /* total byte length of record */
 125         tdb_len_t key_len; /* byte length of key */
 126         tdb_len_t data_len; /* byte length of data */
 127         uint32_t full_hash; /* the full 32 bit hash of the key */
 128         uint32_t magic;   /* try to catch errors */
 129         /* the following union is implied:
 130                 union {
 131                         char record[rec_len];
 132                         struct {
 133                                 char key[key_len];
 134                                 char data[data_len];
 135                         }
 136                         uint32_t totalsize; (tailer)
 137                 }
 138         */
 139 };
 140
 141
 142 /* this is stored at the front of every database */
 143 struct tdb_header {
 144         char magic_food[32]; /* for /etc/magic */
 145         uint32_t version; /* version of the code */
 146         uint32_t hash_size; /* number of hash entries */
 147         tdb_off_t rwlocks; /* obsolete - kept to detect old formats */
 148         tdb_off_t recovery_start; /* offset of transaction recovery region */
 149         tdb_off_t sequence_number; /* used when TDB_SEQNUM is set */
 150         tdb_off_t reserved[29];
 151 };
 152
 153 struct tdb_lock_type {
 154         uint32_t off;
 155         uint32_t count;
 156         uint32_t ltype;
 157 };
 158
 159 struct tdb_traverse_lock {
 160         struct tdb_traverse_lock *next;
 161         uint32_t off;
 162         uint32_t hash;
 163         int lock_rw;
 164 };
 165
 166 enum tdb_lock_flags {
 167         /* WAIT == F_SETLKW, NOWAIT == F_SETLK */
 168         TDB_LOCK_NOWAIT = 0,
 169         TDB_LOCK_WAIT = 1,
 170         /* If set, don't log an error on failure. */
 171         TDB_LOCK_PROBE = 2,
 172         /* If set, don't actually lock at all. */
 173         TDB_LOCK_MARK_ONLY = 4,
 174 };
 175
 176 struct tdb_methods {
 177         int (*tdb_read)(struct tdb_context *, tdb_off_t , void *, tdb_len_t , int );
 178         int (*tdb_write)(struct tdb_context *, tdb_off_t, const void *, tdb_len_t);
 179         void (*next_hash_chain)(struct tdb_context *, uint32_t *);
 180         int (*tdb_oob)(struct tdb_context *, tdb_off_t , int );
 181         int (*tdb_expand_file)(struct tdb_context *, tdb_off_t , tdb_off_t );
 182 };
 183
 184 struct tdb_context {
 185         char *name; /* the name of the database */
 186         void *map_ptr; /* where it is currently mapped */
 187         int fd; /* open file descriptor for the database */
 188         tdb_len_t map_size; /* how much space has been mapped */
 189         int read_only; /* opened read-only */
 190         int traverse_read; /* read-only traversal */
 191         int traverse_write; /* read-write traversal */
 192         struct tdb_lock_type allrecord_lock; /* .offset == upgradable */
 193         int num_lockrecs;
 194         struct tdb_lock_type *lockrecs; /* only real locks, all with count>0 */
 195         enum TDB_ERROR ecode; /* error code for last tdb error */
 196         struct tdb_header header; /* a cached copy of the header */
 197         uint32_t flags; /* the flags passed to tdb_open */
 198         struct tdb_traverse_lock travlocks; /* current traversal locks */
 199         struct tdb_context *next; /* all tdbs to avoid multiple opens */
 200         dev_t device;   /* uniquely identifies this tdb */
 201         ino_t inode;    /* uniquely identifies this tdb */
 202         struct tdb_logging_context log;
 203         unsigned int (*hash_fn)(TDB_DATA *key);
 204         int open_flags; /* flags used in the open - needed by reopen */
 205         const struct tdb_methods *methods;
 206         struct tdb_transaction *transaction;
 207         int page_size;
 208         int max_dead_records;
 209 #ifdef TDB_TRACE
 210         int tracefd;
 211 #endif
 212         volatile sig_atomic_t *interrupt_sig_ptr;
 213 };
 214
 215
 216 /*
 217   internal prototypes
 218 */
 219 int tdb_munmap(struct tdb_context *tdb);
 220 void tdb_mmap(struct tdb_context *tdb);
 221 int tdb_lock(struct tdb_context *tdb, int list, int ltype);
 222 int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype);
 223 int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
 224                   enum tdb_lock_flags flags);
 225 int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
 226                     bool mark_lock);
 227 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
 228 int tdb_brlock(struct tdb_context *tdb,
 229                int rw_type, tdb_off_t offset, size_t len,
 230                enum tdb_lock_flags flags);
 231 int tdb_brunlock(struct tdb_context *tdb,
 232                  int rw_type, tdb_off_t offset, size_t len);
 233 bool tdb_have_extra_locks(struct tdb_context *tdb);
 234 void tdb_release_transaction_locks(struct tdb_context *tdb);
 235 int tdb_transaction_lock(struct tdb_context *tdb, int ltype,
 236                          enum tdb_lock_flags lockflags);
 237 int tdb_transaction_unlock(struct tdb_context *tdb, int ltype);
 238 int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
 239                        enum tdb_lock_flags flags, bool upgradable);
 240 int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock);
 241 int tdb_allrecord_upgrade(struct tdb_context *tdb);
 242 int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off);
 243 int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off);
 244 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 245 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 246 void *tdb_convert(void *buf, uint32_t size);
 247 int tdb_free(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
 248 tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct tdb_record *rec);
 249 int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 250 int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d);
 251 int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off);
 252 int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off);
 253 bool tdb_needs_recovery(struct tdb_context *tdb);
 254 int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
 255 int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct tdb_record *rec);
 256 int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct tdb_record *rec);
 257 unsigned char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);
 258 int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
 259                    tdb_off_t offset, tdb_len_t len,
 260                    int (*parser)(TDB_DATA key, TDB_DATA data,
 261                                  void *private_data),
 262                    void *private_data);
 263 tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t hash, int locktype,
 264                            struct tdb_record *rec);
 265 void tdb_io_init(struct tdb_context *tdb);
 266 int tdb_expand(struct tdb_context *tdb, tdb_off_t size);
 267 int tdb_rec_free_read(struct tdb_context *tdb, tdb_off_t off,
 268                       struct tdb_record *rec);
 269 bool tdb_write_all(int fd, const void *buf, size_t count);
 270 int tdb_transaction_recover(struct tdb_context *tdb);