lib/tdb2/tdb1_open.c

   1  /*
   2    Unix SMB/CIFS implementation.
   3
   4    trivial database library
   5
   6    Copyright (C) Andrew Tridgell              1999-2005
   7    Copyright (C) Paul `Rusty' Russell              2000
   8    Copyright (C) Jeremy Allison                    2000-2003
   9
  10      ** NOTE! The following LGPL license applies to the tdb
  11      ** library. This does NOT imply that all of Samba is released
  12      ** under the LGPL
  13
  14    This library is free software; you can redistribute it and/or
  15    modify it under the terms of the GNU Lesser General Public
  16    License as published by the Free Software Foundation; either
  17    version 3 of the License, or (at your option) any later version.
  18
  19    This library is distributed in the hope that it will be useful,
  20    but WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22    Lesser General Public License for more details.
  23
  24    You should have received a copy of the GNU Lesser General Public
  25    License along with this library; if not, see <http://www.gnu.org/licenses/>.
  26 */
  27
  28 #include "tdb1_private.h"
  29
  30 /* We use two hashes to double-check they're using the right hash function. */
  31 void tdb1_header_hash(struct tdb_context *tdb,
  32                      uint32_t *magic1_hash, uint32_t *magic2_hash)
  33 {
  34         uint32_t tdb1_magic = TDB1_MAGIC;
  35
  36         *magic1_hash = tdb_hash(tdb, TDB_MAGIC_FOOD, sizeof(TDB_MAGIC_FOOD));
  37         *magic2_hash = tdb_hash(tdb, TDB1_CONV(tdb1_magic), sizeof(tdb1_magic));
  38
  39         /* Make sure at least one hash is non-zero! */
  40         if (*magic1_hash == 0 && *magic2_hash == 0)
  41                 *magic1_hash = 1;
  42 }
  43
  44 /* initialise a new database with a specified hash size */
  45 static int tdb1_new_database(struct tdb_context *tdb, int hash_size)
  46 {
  47         struct tdb1_header *newdb;
  48         size_t size;
  49         int ret = -1;
  50
  51         /* We make it up in memory, then write it out if not internal */
  52         size = sizeof(struct tdb1_header) + (hash_size+1)*sizeof(tdb1_off_t);
  53         if (!(newdb = (struct tdb1_header *)calloc(size, 1))) {
  54                 tdb->last_error = TDB_ERR_OOM;
  55                 return -1;
  56         }
  57
  58         /* Fill in the header */
  59         newdb->version = TDB1_VERSION;
  60         newdb->hash_size = hash_size;
  61
  62         tdb1_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);
  63
  64         /* Make sure older tdbs (which don't check the magic hash fields)
  65          * will refuse to open this TDB. */
  66         if (tdb->hash_fn == tdb1_incompatible_hash)
  67                 newdb->rwlocks = TDB1_HASH_RWLOCK_MAGIC;
  68
  69         if (tdb->flags & TDB_INTERNAL) {
  70                 tdb->file->fd = -1;
  71                 tdb->file->map_size = size;
  72                 tdb->file->map_ptr = (char *)newdb;
  73                 memcpy(&tdb->tdb1.header, newdb, sizeof(tdb->tdb1.header));
  74                 /* Convert the `ondisk' version if asked. */
  75                 TDB1_CONV(*newdb);
  76                 return 0;
  77         }
  78         if (lseek(tdb->file->fd, 0, SEEK_SET) == -1)
  79                 goto fail;
  80
  81         if (ftruncate(tdb->file->fd, 0) == -1)
  82                 goto fail;
  83
  84         /* This creates an endian-converted header, as if read from disk */
  85         TDB1_CONV(*newdb);
  86         memcpy(&tdb->tdb1.header, newdb, sizeof(tdb->tdb1.header));
  87         /* Don't endian-convert the magic food! */
  88         memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
  89         /* we still have "ret == -1" here */
  90         if (tdb1_write_all(tdb->file->fd, newdb, size))
  91                 ret = 0;
  92
  93   fail:
  94         SAFE_FREE(newdb);
  95         return ret;
  96 }
  97
  98
  99
 100 /* open the database, creating it if necessary
 101
 102    The open_flags and mode are passed straight to the open call on the
 103    database file. A flags value of O_WRONLY is invalid. The hash size
 104    is advisory, use zero for a default value.
 105
 106    Return is NULL on error, in which case errno is also set.  Don't
 107    try to call tdb1_error or tdb1_errname, just do strerror(errno).
 108
 109    @param name may be NULL for internal databases. */
 110 struct tdb_context *tdb1_open(const char *name, int hash_size, int tdb1_flags,
 111                       int open_flags, mode_t mode)
 112 {
 113         return tdb1_open_ex(name, hash_size, tdb1_flags, open_flags, mode, NULL, NULL);
 114 }
 115
 116 static bool hash_correct(struct tdb_context *tdb,
 117                          uint32_t *m1, uint32_t *m2)
 118 {
 119         tdb1_header_hash(tdb, m1, m2);
 120         return (tdb->tdb1.header.magic1_hash == *m1 &&
 121                 tdb->tdb1.header.magic2_hash == *m2);
 122 }
 123
 124 static bool check_header_hash(struct tdb_context *tdb,
 125                               uint32_t *m1, uint32_t *m2)
 126 {
 127         if (hash_correct(tdb, m1, m2))
 128                 return true;
 129
 130         /* If they use one inbuilt, try the other inbuilt hash. */
 131         if (tdb->hash_fn == tdb1_old_hash)
 132                 tdb->hash_fn = tdb1_incompatible_hash;
 133         else if (tdb->hash_fn == tdb1_incompatible_hash)
 134                 tdb->hash_fn = tdb1_old_hash;
 135         else
 136                 return false;
 137         return hash_correct(tdb, m1, m2);
 138 }
 139
 140 struct tdb_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flags,
 141                                 int open_flags, mode_t mode,
 142                                 const struct tdb1_logging_context *log_ctx,
 143                                 tdb1_hash_func hash_fn)
 144 {
 145         struct tdb_context *tdb;
 146         struct stat st;
 147         int rev = 0;
 148         unsigned v;
 149         const char *hash_alg;
 150         uint32_t magic1, magic2;
 151
 152         if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
 153                 /* Can't log this */
 154                 errno = ENOMEM;
 155                 goto fail;
 156         }
 157         tdb->file = calloc(1, sizeof *tdb->file);
 158         if (!tdb->file) {
 159                 free(tdb);
 160                 errno = ENOMEM;
 161                 goto fail;
 162         }
 163         tdb1_io_init(tdb);
 164         tdb->file->fd = -1;
 165         tdb->name = NULL;
 166         tdb->file->map_ptr = NULL;
 167         tdb->flags = tdb1_flags|TDB_VERSION1;
 168         tdb->open_flags = open_flags;
 169         tdb->lock_fn = tdb_fcntl_lock;
 170         tdb->unlock_fn = tdb_fcntl_unlock;
 171         if (log_ctx) {
 172                 tdb->log_fn = log_ctx->log_fn;
 173                 tdb->log_data = log_ctx->log_private;
 174         } else
 175                 tdb->log_fn = NULL;
 176
 177         if (name == NULL && (tdb1_flags & TDB_INTERNAL)) {
 178                 name = "__TDB1_INTERNAL__";
 179         }
 180
 181         if (name == NULL) {
 182                 tdb->name = (char *)"__NULL__";
 183                 tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 184                            "tdb1_open_ex: called with name == NULL");
 185                 tdb->name = NULL;
 186                 errno = EINVAL;
 187                 goto fail;
 188         }
 189
 190         /* now make a copy of the name, as the caller memory might went away */
 191         if (!(tdb->name = (char *)strdup(name))) {
 192                 /*
 193                  * set the name as the given string, so that tdb1_name() will
 194                  * work in case of an error.
 195                  */
 196                 tdb->name = (char *)name;
 197                 tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
 198                            "tdb1_open_ex: can't strdup(%s)", name);
 199                 tdb->name = NULL;
 200                 errno = ENOMEM;
 201                 goto fail;
 202         }
 203         tdb->hash_seed = 0;
 204
 205         if (hash_fn) {
 206                 tdb->hash_fn = hash_fn;
 207                 if (hash_fn == tdb1_incompatible_hash)
 208                         hash_alg = "tdb1_incompatible_hash";
 209                 else
 210                         hash_alg = "the user defined";
 211         } else {
 212                 tdb->hash_fn = tdb1_old_hash;
 213                 hash_alg = "default";
 214         }
 215
 216         /* cache the page size */
 217         tdb->tdb1.page_size = getpagesize();
 218         if (tdb->tdb1.page_size <= 0) {
 219                 tdb->tdb1.page_size = 0x2000;
 220         }
 221
 222         /* FIXME: Used to be 5 for TDB_VOLATILE. */
 223         tdb->tdb1.max_dead_records = 0;
 224
 225         if ((open_flags & O_ACCMODE) == O_WRONLY) {
 226                 tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
 227                            "tdb1_open_ex: can't open tdb %s write-only",
 228                            name);
 229                 errno = EINVAL;
 230                 goto fail;
 231         }
 232
 233         if (hash_size == 0)
 234                 hash_size = TDB1_DEFAULT_HASH_SIZE;
 235         if ((open_flags & O_ACCMODE) == O_RDONLY) {
 236                 tdb->flags |= TDB_RDONLY;
 237                 /* read only databases don't do locking */
 238                 tdb->flags |= TDB_NOLOCK;
 239         }
 240
 241         /* internal databases don't mmap or lock, and start off cleared */
 242         if (tdb->flags & TDB_INTERNAL) {
 243                 tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
 244                 if (tdb1_new_database(tdb, hash_size) != 0) {
 245                         tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
 246                                    "tdb1_open_ex: tdb1_new_database failed!");
 247                         goto fail;
 248                 }
 249                 goto internal;
 250         }
 251
 252         if ((tdb->file->fd = open(name, open_flags, mode)) == -1) {
 253                 tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 254                            "tdb1_open_ex: could not open file %s: %s",
 255                            name, strerror(errno));
 256                 goto fail;      /* errno set by open(2) */
 257         }
 258
 259         /* on exec, don't inherit the fd */
 260         v = fcntl(tdb->file->fd, F_GETFD, 0);
 261         fcntl(tdb->file->fd, F_SETFD, v | FD_CLOEXEC);
 262
 263         /* ensure there is only one process initialising at once */
 264         if (tdb1_nest_lock(tdb, TDB1_OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
 265                 tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
 266                            "tdb1_open_ex: failed to get open lock on %s: %s",
 267                            name, strerror(errno));
 268                 goto fail;      /* errno set by tdb1_brlock */
 269         }
 270
 271         errno = 0;
 272         if (read(tdb->file->fd, &tdb->tdb1.header, sizeof(tdb->tdb1.header)) != sizeof(tdb->tdb1.header)
 273             || strcmp(tdb->tdb1.header.magic_food, TDB_MAGIC_FOOD) != 0) {
 274                 if (!(open_flags & O_CREAT) || tdb1_new_database(tdb, hash_size) == -1) {
 275                         if (errno == 0) {
 276                                 errno = EIO; /* ie bad format or something */
 277                         }
 278                         goto fail;
 279                 }
 280                 rev = (tdb->flags & TDB_CONVERT);
 281         } else if (tdb->tdb1.header.version != TDB1_VERSION
 282                    && !(rev = (tdb->tdb1.header.version==TDB1_BYTEREV(TDB1_VERSION)))) {
 283                 /* wrong version */
 284                 errno = EIO;
 285                 goto fail;
 286         }
 287         if (!rev)
 288                 tdb->flags &= ~TDB_CONVERT;
 289         else {
 290                 tdb->flags |= TDB_CONVERT;
 291                 tdb1_convert(&tdb->tdb1.header, sizeof(tdb->tdb1.header));
 292         }
 293         if (fstat(tdb->file->fd, &st) == -1)
 294                 goto fail;
 295
 296         if (tdb->tdb1.header.rwlocks != 0 &&
 297             tdb->tdb1.header.rwlocks != TDB1_HASH_RWLOCK_MAGIC) {
 298                 tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 299                            "tdb1_open_ex: spinlocks no longer supported");
 300                 goto fail;
 301         }
 302
 303         if ((tdb->tdb1.header.magic1_hash == 0) && (tdb->tdb1.header.magic2_hash == 0)) {
 304                 /* older TDB without magic hash references */
 305                 tdb->hash_fn = tdb1_old_hash;
 306         } else if (!check_header_hash(tdb, &magic1, &magic2)) {
 307                 tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_USE_ERROR,
 308                            "tdb1_open_ex: "
 309                            "%s was not created with %s hash function we are using\n"
 310                            "magic1_hash[0x%08X %s 0x%08X] "
 311                            "magic2_hash[0x%08X %s 0x%08X]",
 312                            name, hash_alg,
 313                            tdb->tdb1.header.magic1_hash,
 314                            (tdb->tdb1.header.magic1_hash == magic1) ? "==" : "!=",
 315                            magic1,
 316                            tdb->tdb1.header.magic2_hash,
 317                            (tdb->tdb1.header.magic2_hash == magic2) ? "==" : "!=",
 318                            magic2);
 319                 errno = EINVAL;
 320                 goto fail;
 321         }
 322
 323         tdb->file->map_size = st.st_size;
 324         tdb->file->device = st.st_dev;
 325         tdb->file->inode = st.st_ino;
 326         tdb1_mmap(tdb);
 327
 328         /* if needed, run recovery */
 329         if (tdb1_transaction_recover(tdb) == -1) {
 330                 goto fail;
 331         }
 332
 333  internal:
 334         /* Internal (memory-only) databases skip all the code above to
 335          * do with disk files, and resume here by releasing their
 336          * open lock and hooking into the active list. */
 337         if (tdb1_nest_unlock(tdb, TDB1_OPEN_LOCK, F_WRLCK) == -1) {
 338                 goto fail;
 339         }
 340         return tdb;
 341
 342  fail:
 343         { int save_errno = errno;
 344
 345         if (!tdb)
 346                 return NULL;
 347
 348         if (tdb->file->map_ptr) {
 349                 if (tdb->flags & TDB_INTERNAL)
 350                         SAFE_FREE(tdb->file->map_ptr);
 351                 else
 352                         tdb1_munmap(tdb);
 353         }
 354         if (tdb->file->fd != -1)
 355                 if (close(tdb->file->fd) != 0)
 356                         tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 357                                    "tdb1_open_ex: failed to close tdb->fd on error!");
 358         if (tdb->file) {
 359                 SAFE_FREE(tdb->file->lockrecs);
 360                 SAFE_FREE(tdb->file);
 361         }
 362         SAFE_FREE(tdb->name);
 363         SAFE_FREE(tdb);
 364         errno = save_errno;
 365         return NULL;
 366         }
 367 }
 368
 369 /*
 370  * Set the maximum number of dead records per hash chain
 371  */
 372
 373 void tdb1_set_max_dead(struct tdb_context *tdb, int max_dead)
 374 {
 375         tdb->tdb1.max_dead_records = max_dead;
 376 }
 377
 378 /**
 379  * Close a database.
 380  *
 381  * @returns -1 for error; 0 for success.
 382  **/
 383 int tdb1_close(struct tdb_context *tdb)
 384 {
 385         int ret = 0;
 386
 387         if (tdb->tdb1.transaction) {
 388                 tdb1_transaction_cancel(tdb);
 389         }
 390
 391         if (tdb->file->map_ptr) {
 392                 if (tdb->flags & TDB_INTERNAL)
 393                         SAFE_FREE(tdb->file->map_ptr);
 394                 else
 395                         tdb1_munmap(tdb);
 396         }
 397         SAFE_FREE(tdb->name);
 398         if (tdb->file->fd != -1) {
 399                 ret = close(tdb->file->fd);
 400                 tdb->file->fd = -1;
 401         }
 402         SAFE_FREE(tdb->file->lockrecs);
 403         SAFE_FREE(tdb->file);
 404
 405         memset(tdb, 0, sizeof(*tdb));
 406         SAFE_FREE(tdb);
 407
 408         return ret;
 409 }