source3/lib/util_tdb.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    tdb utility functions
   4    Copyright (C) Andrew Tridgell   1992-1998
   5    Copyright (C) Rafal Szczesniak  2002
   6    Copyright (C) Michael Adam      2007
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "system/filesys.h"
  24 #include "util_tdb.h"
  25
  26 #undef malloc
  27 #undef realloc
  28 #undef calloc
  29 #undef strdup
  30
  31 #ifdef BUILD_TDB2
  32 static struct flock flock_struct;
  33
  34 /* Return a value which is none of v1, v2 or v3. */
  35 static inline short int invalid_value(short int v1, short int v2, short int v3)
  36 {
  37         short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
  38         while (try == v1 || try == v2 || try == v3)
  39                 try++;
  40         return try;
  41 }
  42
  43 /* We invalidate in as many ways as we can, so the OS rejects it */
  44 static void invalidate_flock_struct(int signum)
  45 {
  46         flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
  47         flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
  48         flock_struct.l_start = -1;
  49         /* A large negative. */
  50         flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
  51 }
  52
  53 static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
  54                         void *_timeout)
  55 {
  56         int ret, saved_errno;
  57         unsigned int timeout = *(unsigned int *)_timeout;
  58
  59         flock_struct.l_type = rw;
  60         flock_struct.l_whence = SEEK_SET;
  61         flock_struct.l_start = off;
  62         flock_struct.l_len = len;
  63
  64         CatchSignal(SIGALRM, invalidate_flock_struct);
  65         alarm(timeout);
  66
  67         for (;;) {
  68                 if (waitflag)
  69                         ret = fcntl(fd, F_SETLKW, &flock_struct);
  70                 else
  71                         ret = fcntl(fd, F_SETLK, &flock_struct);
  72
  73                 if (ret == 0)
  74                         break;
  75
  76                 /* Not signalled?  Something else went wrong. */
  77                 if (flock_struct.l_len == len) {
  78                         if (errno == EAGAIN || errno == EINTR)
  79                                 continue;
  80                         saved_errno = errno;
  81                         break;
  82                 } else {
  83                         saved_errno = EINTR;
  84                         break;
  85                 }
  86         }
  87
  88         alarm(0);
  89         errno = saved_errno;
  90         return ret;
  91 }
  92
  93 static int tdb_chainlock_with_timeout_internal(struct tdb_context *tdb,
  94                                                TDB_DATA key,
  95                                                unsigned int timeout,
  96                                                int rw_type)
  97 {
  98         union tdb_attribute locking;
  99         enum TDB_ERROR ecode;
 100
 101         if (timeout) {
 102                 locking.base.attr = TDB_ATTRIBUTE_FLOCK;
 103                 ecode = tdb_get_attribute(tdb, &locking);
 104                 if (ecode != TDB_SUCCESS)
 105                         return -1;
 106
 107                 /* Replace locking function with our own. */
 108                 locking.flock.data = &timeout;
 109                 locking.flock.lock = timeout_lock;
 110
 111                 ecode = tdb_set_attribute(tdb, &locking);
 112                 if (ecode != TDB_SUCCESS)
 113                         return -1;
 114         }
 115         if (rw_type == F_RDLCK)
 116                 ecode = tdb_chainlock_read(tdb, key);
 117         else
 118                 ecode = tdb_chainlock(tdb, key);
 119
 120         if (timeout) {
 121                 tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
 122         }
 123         return ecode == TDB_SUCCESS ? 0 : -1;
 124 }
 125 #else
 126 /* these are little tdb utility functions that are meant to make
 127    dealing with a tdb database a little less cumbersome in Samba */
 128
 129 static SIG_ATOMIC_T gotalarm;
 130
 131 /***************************************************************
 132  Signal function to tell us we timed out.
 133 ****************************************************************/
 134
 135 static void gotalarm_sig(int signum)
 136 {
 137         gotalarm = 1;
 138 }
 139
 140 /****************************************************************************
 141  Lock a chain with timeout (in seconds).
 142 ****************************************************************************/
 143
 144 static int tdb_chainlock_with_timeout_internal( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout, int rw_type)
 145 {
 146         /* Allow tdb_chainlock to be interrupted by an alarm. */
 147         int ret;
 148         gotalarm = 0;
 149
 150         if (timeout) {
 151                 CatchSignal(SIGALRM, gotalarm_sig);
 152                 tdb_setalarm_sigptr(tdb, &gotalarm);
 153                 alarm(timeout);
 154         }
 155
 156         if (rw_type == F_RDLCK)
 157                 ret = tdb_chainlock_read(tdb, key);
 158         else
 159                 ret = tdb_chainlock(tdb, key);
 160
 161         if (timeout) {
 162                 alarm(0);
 163                 tdb_setalarm_sigptr(tdb, NULL);
 164                 CatchSignal(SIGALRM, SIG_IGN);
 165                 if (gotalarm && (ret != 0)) {
 166                         DEBUG(0,("tdb_chainlock_with_timeout_internal: alarm (%u) timed out for key %s in tdb %s\n",
 167                                 timeout, key.dptr, tdb_name(tdb)));
 168                         /* TODO: If we time out waiting for a lock, it might
 169                          * be nice to use F_GETLK to get the pid of the
 170                          * process currently holding the lock and print that
 171                          * as part of the debugging message. -- mbp */
 172                         return -1;
 173                 }
 174         }
 175
 176         return ret == 0 ? 0 : -1;
 177 }
 178 #endif /* TDB1 */
 179
 180 /****************************************************************************
 181  Write lock a chain. Return non-zero if timeout or lock failed.
 182 ****************************************************************************/
 183
 184 int tdb_chainlock_with_timeout( TDB_CONTEXT *tdb, TDB_DATA key, unsigned int timeout)
 185 {
 186         return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_WRLCK);
 187 }
 188
 189 int tdb_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval,
 190                                    int timeout)
 191 {
 192         TDB_DATA key = string_term_tdb_data(keyval);
 193
 194         return tdb_chainlock_with_timeout(tdb, key, timeout);
 195 }
 196
 197 /****************************************************************************
 198  Read lock a chain by string. Return non-zero if timeout or lock failed.
 199 ****************************************************************************/
 200
 201 int tdb_read_lock_bystring_with_timeout(TDB_CONTEXT *tdb, const char *keyval, unsigned int timeout)
 202 {
 203         TDB_DATA key = string_term_tdb_data(keyval);
 204
 205         return tdb_chainlock_with_timeout_internal(tdb, key, timeout, F_RDLCK);
 206 }
 207
 208
 209
 210
 211 int tdb_trans_store_bystring(TDB_CONTEXT *tdb, const char *keystr,
 212                              TDB_DATA data, int flags)
 213 {
 214         TDB_DATA key = string_term_tdb_data(keystr);
 215
 216         return tdb_trans_store(tdb, key, data, flags);
 217 }
 218
 219 /****************************************************************************
 220  Useful pair of routines for packing/unpacking data consisting of
 221  integers and strings.
 222 ****************************************************************************/
 223
 224 static size_t tdb_pack_va(uint8 *buf, int bufsize, const char *fmt, va_list ap)
 225 {
 226         uint8 bt;
 227         uint16 w;
 228         uint32 d;
 229         int i;
 230         void *p;
 231         int len;
 232         char *s;
 233         char c;
 234         uint8 *buf0 = buf;
 235         const char *fmt0 = fmt;
 236         int bufsize0 = bufsize;
 237
 238         while (*fmt) {
 239                 switch ((c = *fmt++)) {
 240                 case 'b': /* unsigned 8-bit integer */
 241                         len = 1;
 242                         bt = (uint8)va_arg(ap, int);
 243                         if (bufsize && bufsize >= len)
 244                                 SSVAL(buf, 0, bt);
 245                         break;
 246                 case 'w': /* unsigned 16-bit integer */
 247                         len = 2;
 248                         w = (uint16)va_arg(ap, int);
 249                         if (bufsize && bufsize >= len)
 250                                 SSVAL(buf, 0, w);
 251                         break;
 252                 case 'd': /* signed 32-bit integer (standard int in most systems) */
 253                         len = 4;
 254                         d = va_arg(ap, uint32);
 255                         if (bufsize && bufsize >= len)
 256                                 SIVAL(buf, 0, d);
 257                         break;
 258                 case 'p': /* pointer */
 259                         len = 4;
 260                         p = va_arg(ap, void *);
 261                         d = p?1:0;
 262                         if (bufsize && bufsize >= len)
 263                                 SIVAL(buf, 0, d);
 264                         break;
 265                 case 'P': /* null-terminated string */
 266                         s = va_arg(ap,char *);
 267                         w = strlen(s);
 268                         len = w + 1;
 269                         if (bufsize && bufsize >= len)
 270                                 memcpy(buf, s, len);
 271                         break;
 272                 case 'f': /* null-terminated string */
 273                         s = va_arg(ap,char *);
 274                         w = strlen(s);
 275                         len = w + 1;
 276                         if (bufsize && bufsize >= len)
 277                                 memcpy(buf, s, len);
 278                         break;
 279                 case 'B': /* fixed-length string */
 280                         i = va_arg(ap, int);
 281                         s = va_arg(ap, char *);
 282                         len = 4+i;
 283                         if (bufsize && bufsize >= len) {
 284                                 SIVAL(buf, 0, i);
 285                                 memcpy(buf+4, s, i);
 286                         }
 287                         break;
 288                 default:
 289                         DEBUG(0,("Unknown tdb_pack format %c in %s\n",
 290                                  c, fmt));
 291                         len = 0;
 292                         break;
 293                 }
 294
 295                 buf += len;
 296                 if (bufsize)
 297                         bufsize -= len;
 298                 if (bufsize < 0)
 299                         bufsize = 0;
 300         }
 301
 302         DEBUG(18,("tdb_pack_va(%s, %d) -> %d\n",
 303                  fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
 304
 305         return PTR_DIFF(buf, buf0);
 306 }
 307
 308 size_t tdb_pack(uint8 *buf, int bufsize, const char *fmt, ...)
 309 {
 310         va_list ap;
 311         size_t result;
 312
 313         va_start(ap, fmt);
 314         result = tdb_pack_va(buf, bufsize, fmt, ap);
 315         va_end(ap);
 316         return result;
 317 }
 318
 319 bool tdb_pack_append(TALLOC_CTX *mem_ctx, uint8 **buf, size_t *len,
 320                      const char *fmt, ...)
 321 {
 322         va_list ap;
 323         size_t len1, len2;
 324
 325         va_start(ap, fmt);
 326         len1 = tdb_pack_va(NULL, 0, fmt, ap);
 327         va_end(ap);
 328
 329         if (mem_ctx != NULL) {
 330                 *buf = talloc_realloc(mem_ctx, *buf, uint8,
 331                                             (*len) + len1);
 332         } else {
 333                 *buf = SMB_REALLOC_ARRAY(*buf, uint8, (*len) + len1);
 334         }
 335
 336         if (*buf == NULL) {
 337                 return False;
 338         }
 339
 340         va_start(ap, fmt);
 341         len2 = tdb_pack_va((*buf)+(*len), len1, fmt, ap);
 342         va_end(ap);
 343
 344         if (len1 != len2) {
 345                 return False;
 346         }
 347
 348         *len += len2;
 349
 350         return True;
 351 }
 352
 353 /****************************************************************************
 354  Useful pair of routines for packing/unpacking data consisting of
 355  integers and strings.
 356 ****************************************************************************/
 357
 358 int tdb_unpack(const uint8 *buf, int bufsize, const char *fmt, ...)
 359 {
 360         va_list ap;
 361         uint8 *bt;
 362         uint16 *w;
 363         uint32 *d;
 364         int len;
 365         int *i;
 366         void **p;
 367         char *s, **b, **ps;
 368         char c;
 369         const uint8 *buf0 = buf;
 370         const char *fmt0 = fmt;
 371         int bufsize0 = bufsize;
 372
 373         va_start(ap, fmt);
 374
 375         while (*fmt) {
 376                 switch ((c=*fmt++)) {
 377                 case 'b': /* unsigned 8-bit integer */
 378                         len = 1;
 379                         bt = va_arg(ap, uint8 *);
 380                         if (bufsize < len)
 381                                 goto no_space;
 382                         *bt = SVAL(buf, 0);
 383                         break;
 384                 case 'w': /* unsigned 16-bit integer */
 385                         len = 2;
 386                         w = va_arg(ap, uint16 *);
 387                         if (bufsize < len)
 388                                 goto no_space;
 389                         *w = SVAL(buf, 0);
 390                         break;
 391                 case 'd': /* unsigned 32-bit integer (standard int in most systems) */
 392                         len = 4;
 393                         d = va_arg(ap, uint32 *);
 394                         if (bufsize < len)
 395                                 goto no_space;
 396                         *d = IVAL(buf, 0);
 397                         break;
 398                 case 'p': /* pointer */
 399                         len = 4;
 400                         p = va_arg(ap, void **);
 401                         if (bufsize < len)
 402                                 goto no_space;
 403                         /*
 404                          * This isn't a real pointer - only a token (1 or 0)
 405                          * to mark the fact a pointer is present.
 406                          */
 407
 408                         *p = (void *)(IVAL(buf, 0) ? (void *)1 : NULL);
 409                         break;
 410                 case 'P': /* null-terminated string */
 411                         /* Return malloc'ed string. */
 412                         ps = va_arg(ap,char **);
 413                         len = strnlen((const char *)buf, bufsize) + 1;
 414                         if (bufsize < len)
 415                                 goto no_space;
 416                         *ps = SMB_STRDUP((const char *)buf);
 417                         break;
 418                 case 'f': /* null-terminated string */
 419                         s = va_arg(ap,char *);
 420                         len = strnlen((const char *)buf, bufsize) + 1;
 421                         if (bufsize < len || len > sizeof(fstring))
 422                                 goto no_space;
 423                         memcpy(s, buf, len);
 424                         break;
 425                 case 'B': /* fixed-length string */
 426                         i = va_arg(ap, int *);
 427                         b = va_arg(ap, char **);
 428                         len = 4;
 429                         if (bufsize < len)
 430                                 goto no_space;
 431                         *i = IVAL(buf, 0);
 432                         if (! *i) {
 433                                 *b = NULL;
 434                                 break;
 435                         }
 436                         len += *i;
 437                         if (bufsize < len)
 438                                 goto no_space;
 439                         *b = (char *)SMB_MALLOC(*i);
 440                         if (! *b)
 441                                 goto no_space;
 442                         memcpy(*b, buf+4, *i);
 443                         break;
 444                 default:
 445                         DEBUG(0,("Unknown tdb_unpack format %c in %s\n",
 446                                  c, fmt));
 447
 448                         len = 0;
 449                         break;
 450                 }
 451
 452                 buf += len;
 453                 bufsize -= len;
 454         }
 455
 456         va_end(ap);
 457
 458         DEBUG(18,("tdb_unpack(%s, %d) -> %d\n",
 459                  fmt0, bufsize0, (int)PTR_DIFF(buf, buf0)));
 460
 461         return PTR_DIFF(buf, buf0);
 462
 463  no_space:
 464         va_end(ap);
 465         return -1;
 466 }
 467
 468
 469 /****************************************************************************
 470  Log tdb messages via DEBUG().
 471 ****************************************************************************/
 472
 473 #ifdef BUILD_TDB2
 474 static void tdb_log(TDB_CONTEXT *tdb, enum tdb_log_level level,
 475                     enum TDB_ERROR ecode, const char *message, void *unused)
 476 {
 477         DEBUG((int)level, ("tdb(%s):%s: %s",
 478                            tdb_name(tdb) ? tdb_name(tdb) : "unnamed",
 479                            tdb_errorstr(ecode), message));
 480 }
 481 #else
 482 static void tdb_log(TDB_CONTEXT *tdb, enum tdb_debug_level level, const char *format, ...)
 483 {
 484         va_list ap;
 485         char *ptr = NULL;
 486         int ret;
 487
 488         va_start(ap, format);
 489         ret = vasprintf(&ptr, format, ap);
 490         va_end(ap);
 491
 492         if ((ret == -1) || !*ptr)
 493                 return;
 494
 495         DEBUG((int)level, ("tdb(%s): %s", tdb_name(tdb) ? tdb_name(tdb) : "unnamed", ptr));
 496         SAFE_FREE(ptr);
 497 }
 498 #endif /* TDB1 */
 499
 500 /****************************************************************************
 501  Like tdb_open() but also setup a logging function that redirects to
 502  the samba DEBUG() system.
 503 ****************************************************************************/
 504
 505 TDB_CONTEXT *tdb_open_log(const char *name, int hash_size, int tdb_flags,
 506                           int open_flags, mode_t mode)
 507 {
 508         TDB_CONTEXT *tdb;
 509
 510         if (!lp_use_mmap())
 511                 tdb_flags |= TDB_NOMMAP;
 512
 513         if ((hash_size == 0) && (name != NULL)) {
 514                 const char *base = strrchr_m(name, '/');
 515                 if (base != NULL) {
 516                         base += 1;
 517                 }
 518                 else {
 519                         base = name;
 520                 }
 521                 hash_size = lp_parm_int(-1, "tdb_hashsize", base, 0);
 522         }
 523
 524         tdb = tdb_open_compat(name, hash_size, tdb_flags,
 525                               open_flags, mode, tdb_log, NULL);
 526         if (!tdb)
 527                 return NULL;
 528
 529         return tdb;
 530 }
 531
 532 /****************************************************************************
 533  tdb_store, wrapped in a transaction. This way we make sure that a process
 534  that dies within writing does not leave a corrupt tdb behind.
 535 ****************************************************************************/
 536
 537 int tdb_trans_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf,
 538                     int flag)
 539 {
 540         int res;
 541
 542         if ((res = tdb_transaction_start(tdb)) != 0) {
 543                 DEBUG(5, ("tdb_transaction_start failed\n"));
 544                 return res;
 545         }
 546
 547         if ((res = tdb_store(tdb, key, dbuf, flag)) != 0) {
 548                 DEBUG(10, ("tdb_store failed\n"));
 549                 tdb_transaction_cancel(tdb);
 550                 return res;
 551         }
 552
 553         if ((res = tdb_transaction_commit(tdb)) != 0) {
 554                 DEBUG(5, ("tdb_transaction_commit failed\n"));
 555         }
 556
 557         return res;
 558 }
 559
 560 /****************************************************************************
 561  tdb_delete, wrapped in a transaction. This way we make sure that a process
 562  that dies within deleting does not leave a corrupt tdb behind.
 563 ****************************************************************************/
 564
 565 int tdb_trans_delete(struct tdb_context *tdb, TDB_DATA key)
 566 {
 567         int res;
 568
 569         if ((res = tdb_transaction_start(tdb)) != 0) {
 570                 DEBUG(5, ("tdb_transaction_start failed\n"));
 571                 return res;
 572         }
 573
 574         if ((res = tdb_delete(tdb, key)) != 0) {
 575                 DEBUG(10, ("tdb_delete failed\n"));
 576                 tdb_transaction_cancel(tdb);
 577                 return res;
 578         }
 579
 580         if ((res = tdb_transaction_commit(tdb)) != 0) {
 581                 DEBUG(5, ("tdb_transaction_commit failed\n"));
 582         }
 583
 584         return res;
 585 }
 586
 587 int tdb_data_cmp(TDB_DATA t1, TDB_DATA t2)
 588 {
 589         int ret;
 590         if (t1.dptr == NULL && t2.dptr != NULL) {
 591                 return -1;
 592         }
 593         if (t1.dptr != NULL && t2.dptr == NULL) {
 594                 return 1;
 595         }
 596         if (t1.dptr == t2.dptr) {
 597                 return t1.dsize - t2.dsize;
 598         }
 599         ret = memcmp(t1.dptr, t2.dptr, MIN(t1.dsize, t2.dsize));
 600         if (ret == 0) {
 601                 return t1.dsize - t2.dsize;
 602         }
 603         return ret;
 604 }