src/loadext.c

   1 /*
   2 ** 2006 June 7
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 *************************************************************************
  12 ** This file contains code used to dynamically load extensions into
  13 ** the SQLite library.
  14 */
  15
  16 #ifndef SQLITE_CORE
  17   #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
  18 #endif
  19 #include "sqlite3ext.h"
  20 #include "sqliteInt.h"
  21 #include <string.h>
  22
  23 #ifndef SQLITE_OMIT_LOAD_EXTENSION
  24
  25 /*
  26 ** Some API routines are omitted when various features are
  27 ** excluded from a build of SQLite.  Substitute a NULL pointer
  28 ** for any missing APIs.
  29 */
  30 #ifndef SQLITE_ENABLE_COLUMN_METADATA
  31 # define sqlite3_column_database_name   0
  32 # define sqlite3_column_database_name16 0
  33 # define sqlite3_column_table_name      0
  34 # define sqlite3_column_table_name16    0
  35 # define sqlite3_column_origin_name     0
  36 # define sqlite3_column_origin_name16   0
  37 # define sqlite3_table_column_metadata  0
  38 #endif
  39
  40 #ifdef SQLITE_OMIT_AUTHORIZATION
  41 # define sqlite3_set_authorizer         0
  42 #endif
  43
  44 #ifdef SQLITE_OMIT_UTF16
  45 # define sqlite3_bind_text16            0
  46 # define sqlite3_collation_needed16     0
  47 # define sqlite3_column_decltype16      0
  48 # define sqlite3_column_name16          0
  49 # define sqlite3_column_text16          0
  50 # define sqlite3_complete16             0
  51 # define sqlite3_create_collation16     0
  52 # define sqlite3_create_function16      0
  53 # define sqlite3_errmsg16               0
  54 # define sqlite3_open16                 0
  55 # define sqlite3_prepare16              0
  56 # define sqlite3_prepare16_v2           0
  57 # define sqlite3_result_error16         0
  58 # define sqlite3_result_text16          0
  59 # define sqlite3_result_text16be        0
  60 # define sqlite3_result_text16le        0
  61 # define sqlite3_value_text16           0
  62 # define sqlite3_value_text16be         0
  63 # define sqlite3_value_text16le         0
  64 # define sqlite3_column_database_name16 0
  65 # define sqlite3_column_table_name16    0
  66 # define sqlite3_column_origin_name16   0
  67 #endif
  68
  69 #ifdef SQLITE_OMIT_COMPLETE
  70 # define sqlite3_complete 0
  71 # define sqlite3_complete16 0
  72 #endif
  73
  74 #ifdef SQLITE_OMIT_DECLTYPE
  75 # define sqlite3_column_decltype16      0
  76 # define sqlite3_column_decltype        0
  77 #endif
  78
  79 #ifdef SQLITE_OMIT_PROGRESS_CALLBACK
  80 # define sqlite3_progress_handler 0
  81 #endif
  82
  83 #ifdef SQLITE_OMIT_VIRTUALTABLE
  84 # define sqlite3_create_module 0
  85 # define sqlite3_create_module_v2 0
  86 # define sqlite3_declare_vtab 0
  87 # define sqlite3_vtab_config 0
  88 # define sqlite3_vtab_on_conflict 0
  89 #endif
  90
  91 #ifdef SQLITE_OMIT_SHARED_CACHE
  92 # define sqlite3_enable_shared_cache 0
  93 #endif
  94
  95 #ifdef SQLITE_OMIT_TRACE
  96 # define sqlite3_profile       0
  97 # define sqlite3_trace         0
  98 #endif
  99
 100 #ifdef SQLITE_OMIT_GET_TABLE
 101 # define sqlite3_free_table    0
 102 # define sqlite3_get_table     0
 103 #endif
 104
 105 #ifdef SQLITE_OMIT_INCRBLOB
 106 #define sqlite3_bind_zeroblob  0
 107 #define sqlite3_blob_bytes     0
 108 #define sqlite3_blob_close     0
 109 #define sqlite3_blob_open      0
 110 #define sqlite3_blob_read      0
 111 #define sqlite3_blob_write     0
 112 #define sqlite3_blob_reopen    0
 113 #endif
 114
 115 /*
 116 ** The following structure contains pointers to all SQLite API routines.
 117 ** A pointer to this structure is passed into extensions when they are
 118 ** loaded so that the extension can make calls back into the SQLite
 119 ** library.
 120 **
 121 ** When adding new APIs, add them to the bottom of this structure
 122 ** in order to preserve backwards compatibility.
 123 **
 124 ** Extensions that use newer APIs should first call the
 125 ** sqlite3_libversion_number() to make sure that the API they
 126 ** intend to use is supported by the library.  Extensions should
 127 ** also check to make sure that the pointer to the function is
 128 ** not NULL before calling it.
 129 */
 130 static const sqlite3_api_routines sqlite3Apis = {
 131   sqlite3_aggregate_context,
 132 #ifndef SQLITE_OMIT_DEPRECATED
 133   sqlite3_aggregate_count,
 134 #else
 135   0,
 136 #endif
 137   sqlite3_bind_blob,
 138   sqlite3_bind_double,
 139   sqlite3_bind_int,
 140   sqlite3_bind_int64,
 141   sqlite3_bind_null,
 142   sqlite3_bind_parameter_count,
 143   sqlite3_bind_parameter_index,
 144   sqlite3_bind_parameter_name,
 145   sqlite3_bind_text,
 146   sqlite3_bind_text16,
 147   sqlite3_bind_value,
 148   sqlite3_busy_handler,
 149   sqlite3_busy_timeout,
 150   sqlite3_changes,
 151   sqlite3_close,
 152   sqlite3_collation_needed,
 153   sqlite3_collation_needed16,
 154   sqlite3_column_blob,
 155   sqlite3_column_bytes,
 156   sqlite3_column_bytes16,
 157   sqlite3_column_count,
 158   sqlite3_column_database_name,
 159   sqlite3_column_database_name16,
 160   sqlite3_column_decltype,
 161   sqlite3_column_decltype16,
 162   sqlite3_column_double,
 163   sqlite3_column_int,
 164   sqlite3_column_int64,
 165   sqlite3_column_name,
 166   sqlite3_column_name16,
 167   sqlite3_column_origin_name,
 168   sqlite3_column_origin_name16,
 169   sqlite3_column_table_name,
 170   sqlite3_column_table_name16,
 171   sqlite3_column_text,
 172   sqlite3_column_text16,
 173   sqlite3_column_type,
 174   sqlite3_column_value,
 175   sqlite3_commit_hook,
 176   sqlite3_complete,
 177   sqlite3_complete16,
 178   sqlite3_create_collation,
 179   sqlite3_create_collation16,
 180   sqlite3_create_function,
 181   sqlite3_create_function16,
 182   sqlite3_create_module,
 183   sqlite3_data_count,
 184   sqlite3_db_handle,
 185   sqlite3_declare_vtab,
 186   sqlite3_enable_shared_cache,
 187   sqlite3_errcode,
 188   sqlite3_errmsg,
 189   sqlite3_errmsg16,
 190   sqlite3_exec,
 191 #ifndef SQLITE_OMIT_DEPRECATED
 192   sqlite3_expired,
 193 #else
 194   0,
 195 #endif
 196   sqlite3_finalize,
 197   sqlite3_free,
 198   sqlite3_free_table,
 199   sqlite3_get_autocommit,
 200   sqlite3_get_auxdata,
 201   sqlite3_get_table,
 202   0,     /* Was sqlite3_global_recover(), but that function is deprecated */
 203   sqlite3_interrupt,
 204   sqlite3_last_insert_rowid,
 205   sqlite3_libversion,
 206   sqlite3_libversion_number,
 207   sqlite3_malloc,
 208   sqlite3_mprintf,
 209   sqlite3_open,
 210   sqlite3_open16,
 211   sqlite3_prepare,
 212   sqlite3_prepare16,
 213   sqlite3_profile,
 214   sqlite3_progress_handler,
 215   sqlite3_realloc,
 216   sqlite3_reset,
 217   sqlite3_result_blob,
 218   sqlite3_result_double,
 219   sqlite3_result_error,
 220   sqlite3_result_error16,
 221   sqlite3_result_int,
 222   sqlite3_result_int64,
 223   sqlite3_result_null,
 224   sqlite3_result_text,
 225   sqlite3_result_text16,
 226   sqlite3_result_text16be,
 227   sqlite3_result_text16le,
 228   sqlite3_result_value,
 229   sqlite3_rollback_hook,
 230   sqlite3_set_authorizer,
 231   sqlite3_set_auxdata,
 232   sqlite3_snprintf,
 233   sqlite3_step,
 234   sqlite3_table_column_metadata,
 235 #ifndef SQLITE_OMIT_DEPRECATED
 236   sqlite3_thread_cleanup,
 237 #else
 238   0,
 239 #endif
 240   sqlite3_total_changes,
 241   sqlite3_trace,
 242 #ifndef SQLITE_OMIT_DEPRECATED
 243   sqlite3_transfer_bindings,
 244 #else
 245   0,
 246 #endif
 247   sqlite3_update_hook,
 248   sqlite3_user_data,
 249   sqlite3_value_blob,
 250   sqlite3_value_bytes,
 251   sqlite3_value_bytes16,
 252   sqlite3_value_double,
 253   sqlite3_value_int,
 254   sqlite3_value_int64,
 255   sqlite3_value_numeric_type,
 256   sqlite3_value_text,
 257   sqlite3_value_text16,
 258   sqlite3_value_text16be,
 259   sqlite3_value_text16le,
 260   sqlite3_value_type,
 261   sqlite3_vmprintf,
 262   /*
 263   ** The original API set ends here.  All extensions can call any
 264   ** of the APIs above provided that the pointer is not NULL.  But
 265   ** before calling APIs that follow, extension should check the
 266   ** sqlite3_libversion_number() to make sure they are dealing with
 267   ** a library that is new enough to support that API.
 268   *************************************************************************
 269   */
 270   sqlite3_overload_function,
 271
 272   /*
 273   ** Added after 3.3.13
 274   */
 275   sqlite3_prepare_v2,
 276   sqlite3_prepare16_v2,
 277   sqlite3_clear_bindings,
 278
 279   /*
 280   ** Added for 3.4.1
 281   */
 282   sqlite3_create_module_v2,
 283
 284   /*
 285   ** Added for 3.5.0
 286   */
 287   sqlite3_bind_zeroblob,
 288   sqlite3_blob_bytes,
 289   sqlite3_blob_close,
 290   sqlite3_blob_open,
 291   sqlite3_blob_read,
 292   sqlite3_blob_write,
 293   sqlite3_create_collation_v2,
 294   sqlite3_file_control,
 295   sqlite3_memory_highwater,
 296   sqlite3_memory_used,
 297 #ifdef SQLITE_MUTEX_OMIT
 298   0,
 299   0,
 300   0,
 301   0,
 302   0,
 303 #else
 304   sqlite3_mutex_alloc,
 305   sqlite3_mutex_enter,
 306   sqlite3_mutex_free,
 307   sqlite3_mutex_leave,
 308   sqlite3_mutex_try,
 309 #endif
 310   sqlite3_open_v2,
 311   sqlite3_release_memory,
 312   sqlite3_result_error_nomem,
 313   sqlite3_result_error_toobig,
 314   sqlite3_sleep,
 315   sqlite3_soft_heap_limit,
 316   sqlite3_vfs_find,
 317   sqlite3_vfs_register,
 318   sqlite3_vfs_unregister,
 319
 320   /*
 321   ** Added for 3.5.8
 322   */
 323   sqlite3_threadsafe,
 324   sqlite3_result_zeroblob,
 325   sqlite3_result_error_code,
 326   sqlite3_test_control,
 327   sqlite3_randomness,
 328   sqlite3_context_db_handle,
 329
 330   /*
 331   ** Added for 3.6.0
 332   */
 333   sqlite3_extended_result_codes,
 334   sqlite3_limit,
 335   sqlite3_next_stmt,
 336   sqlite3_sql,
 337   sqlite3_status,
 338
 339   /*
 340   ** Added for 3.7.4
 341   */
 342   sqlite3_backup_finish,
 343   sqlite3_backup_init,
 344   sqlite3_backup_pagecount,
 345   sqlite3_backup_remaining,
 346   sqlite3_backup_step,
 347 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
 348   sqlite3_compileoption_get,
 349   sqlite3_compileoption_used,
 350 #else
 351   0,
 352   0,
 353 #endif
 354   sqlite3_create_function_v2,
 355   sqlite3_db_config,
 356   sqlite3_db_mutex,
 357   sqlite3_db_status,
 358   sqlite3_extended_errcode,
 359   sqlite3_log,
 360   sqlite3_soft_heap_limit64,
 361   sqlite3_sourceid,
 362   sqlite3_stmt_status,
 363   sqlite3_strnicmp,
 364 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
 365   sqlite3_unlock_notify,
 366 #else
 367   0,
 368 #endif
 369 #ifndef SQLITE_OMIT_WAL
 370   sqlite3_wal_autocheckpoint,
 371   sqlite3_wal_checkpoint,
 372   sqlite3_wal_hook,
 373 #else
 374   0,
 375   0,
 376   0,
 377 #endif
 378   sqlite3_blob_reopen,
 379   sqlite3_vtab_config,
 380   sqlite3_vtab_on_conflict,
 381   sqlite3_close_v2,
 382   sqlite3_db_filename,
 383   sqlite3_db_readonly,
 384   sqlite3_db_release_memory,
 385   sqlite3_errstr,
 386   sqlite3_stmt_busy,
 387   sqlite3_stmt_readonly,
 388   sqlite3_stricmp,
 389   sqlite3_uri_boolean,
 390   sqlite3_uri_int64,
 391   sqlite3_uri_parameter,
 392   sqlite3_vsnprintf,
 393   sqlite3_wal_checkpoint_v2
 394 };
 395
 396 /*
 397 ** Attempt to load an SQLite extension library contained in the file
 398 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
 399 ** default entry point name (sqlite3_extension_init) is used.  Use
 400 ** of the default name is recommended.
 401 **
 402 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
 403 **
 404 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
 405 ** error message text.  The calling function should free this memory
 406 ** by calling sqlite3DbFree(db, ).
 407 */
 408 static int sqlite3LoadExtension(
 409   sqlite3 *db,          /* Load the extension into this database connection */
 410   const char *zFile,    /* Name of the shared library containing extension */
 411   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
 412   char **pzErrMsg       /* Put error message here if not 0 */
 413 ){
 414   sqlite3_vfs *pVfs = db->pVfs;
 415   void *handle;
 416   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
 417   char *zErrmsg = 0;
 418   const char *zEntry;
 419   char *zAltEntry = 0;
 420   void **aHandle;
 421   int nMsg = 300 + sqlite3Strlen30(zFile);
 422   int ii;
 423
 424   /* Shared library endings to try if zFile cannot be loaded as written */
 425   static const char *azEndings[] = {
 426 #if SQLITE_OS_WIN
 427      "dll"
 428 #elif defined(__APPLE__)
 429      "dylib"
 430 #else
 431      "so"
 432 #endif
 433   };
 434
 435
 436   if( pzErrMsg ) *pzErrMsg = 0;
 437
 438   /* Ticket #1863.  To avoid a creating security problems for older
 439   ** applications that relink against newer versions of SQLite, the
 440   ** ability to run load_extension is turned off by default.  One
 441   ** must call sqlite3_enable_load_extension() to turn on extension
 442   ** loading.  Otherwise you get the following error.
 443   */
 444   if( (db->flags & SQLITE_LoadExtension)==0 ){
 445     if( pzErrMsg ){
 446       *pzErrMsg = sqlite3_mprintf("not authorized");
 447     }
 448     return SQLITE_ERROR;
 449   }
 450
 451   zEntry = zProc ? zProc : "sqlite3_extension_init";
 452
 453   handle = sqlite3OsDlOpen(pVfs, zFile);
 454 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
 455   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
 456     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
 457     if( zAltFile==0 ) return SQLITE_NOMEM;
 458     handle = sqlite3OsDlOpen(pVfs, zAltFile);
 459     sqlite3_free(zAltFile);
 460   }
 461 #endif
 462   if( handle==0 ){
 463     if( pzErrMsg ){
 464       *pzErrMsg = zErrmsg = sqlite3_malloc(nMsg);
 465       if( zErrmsg ){
 466         sqlite3_snprintf(nMsg, zErrmsg,
 467             "unable to open shared library [%s]", zFile);
 468         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
 469       }
 470     }
 471     return SQLITE_ERROR;
 472   }
 473   xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
 474                    sqlite3OsDlSym(pVfs, handle, zEntry);
 475
 476   /* If no entry point was specified and the default legacy
 477   ** entry point name "sqlite3_extension_init" was not found, then
 478   ** construct an entry point name "sqlite3_X_init" where the X is
 479   ** replaced by the lowercase value of every ASCII alphabetic
 480   ** character in the filename after the last "/" upto the first ".",
 481   ** and eliding the first three characters if they are "lib".
 482   ** Examples:
 483   **
 484   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
 485   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
 486   */
 487   if( xInit==0 && zProc==0 ){
 488     int iFile, iEntry, c;
 489     int ncFile = sqlite3Strlen30(zFile);
 490     zAltEntry = sqlite3_malloc(ncFile+30);
 491     if( zAltEntry==0 ){
 492       sqlite3OsDlClose(pVfs, handle);
 493       return SQLITE_NOMEM;
 494     }
 495     memcpy(zAltEntry, "sqlite3_", 8);
 496     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
 497     iFile++;
 498     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
 499     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
 500       if( sqlite3Isalpha(c) ){
 501         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
 502       }
 503     }
 504     memcpy(zAltEntry+iEntry, "_init", 6);
 505     zEntry = zAltEntry;
 506     xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
 507                      sqlite3OsDlSym(pVfs, handle, zEntry);
 508   }
 509   if( xInit==0 ){
 510     if( pzErrMsg ){
 511       nMsg += sqlite3Strlen30(zEntry);
 512       *pzErrMsg = zErrmsg = sqlite3_malloc(nMsg);
 513       if( zErrmsg ){
 514         sqlite3_snprintf(nMsg, zErrmsg,
 515             "no entry point [%s] in shared library [%s]", zEntry, zFile);
 516         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
 517       }
 518     }
 519     sqlite3OsDlClose(pVfs, handle);
 520     sqlite3_free(zAltEntry);
 521     return SQLITE_ERROR;
 522   }
 523   sqlite3_free(zAltEntry);
 524   if( xInit(db, &zErrmsg, &sqlite3Apis) ){
 525     if( pzErrMsg ){
 526       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
 527     }
 528     sqlite3_free(zErrmsg);
 529     sqlite3OsDlClose(pVfs, handle);
 530     return SQLITE_ERROR;
 531   }
 532
 533   /* Append the new shared library handle to the db->aExtension array. */
 534   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
 535   if( aHandle==0 ){
 536     return SQLITE_NOMEM;
 537   }
 538   if( db->nExtension>0 ){
 539     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
 540   }
 541   sqlite3DbFree(db, db->aExtension);
 542   db->aExtension = aHandle;
 543
 544   db->aExtension[db->nExtension++] = handle;
 545   return SQLITE_OK;
 546 }
 547 int sqlite3_load_extension(
 548   sqlite3 *db,          /* Load the extension into this database connection */
 549   const char *zFile,    /* Name of the shared library containing extension */
 550   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
 551   char **pzErrMsg       /* Put error message here if not 0 */
 552 ){
 553   int rc;
 554   sqlite3_mutex_enter(db->mutex);
 555   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
 556   rc = sqlite3ApiExit(db, rc);
 557   sqlite3_mutex_leave(db->mutex);
 558   return rc;
 559 }
 560
 561 /*
 562 ** Call this routine when the database connection is closing in order
 563 ** to clean up loaded extensions
 564 */
 565 void sqlite3CloseExtensions(sqlite3 *db){
 566   int i;
 567   assert( sqlite3_mutex_held(db->mutex) );
 568   for(i=0; i<db->nExtension; i++){
 569     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
 570   }
 571   sqlite3DbFree(db, db->aExtension);
 572 }
 573
 574 /*
 575 ** Enable or disable extension loading.  Extension loading is disabled by
 576 ** default so as not to open security holes in older applications.
 577 */
 578 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
 579   sqlite3_mutex_enter(db->mutex);
 580   if( onoff ){
 581     db->flags |= SQLITE_LoadExtension;
 582   }else{
 583     db->flags &= ~SQLITE_LoadExtension;
 584   }
 585   sqlite3_mutex_leave(db->mutex);
 586   return SQLITE_OK;
 587 }
 588
 589 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
 590
 591 /*
 592 ** The auto-extension code added regardless of whether or not extension
 593 ** loading is supported.  We need a dummy sqlite3Apis pointer for that
 594 ** code if regular extension loading is not available.  This is that
 595 ** dummy pointer.
 596 */
 597 #ifdef SQLITE_OMIT_LOAD_EXTENSION
 598 static const sqlite3_api_routines sqlite3Apis = { 0 };
 599 #endif
 600
 601
 602 /*
 603 ** The following object holds the list of automatically loaded
 604 ** extensions.
 605 **
 606 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
 607 ** mutex must be held while accessing this list.
 608 */
 609 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
 610 static SQLITE_WSD struct sqlite3AutoExtList {
 611   int nExt;              /* Number of entries in aExt[] */
 612   void (**aExt)(void);   /* Pointers to the extension init functions */
 613 } sqlite3Autoext = { 0, 0 };
 614
 615 /* The "wsdAutoext" macro will resolve to the autoextension
 616 ** state vector.  If writable static data is unsupported on the target,
 617 ** we have to locate the state vector at run-time.  In the more common
 618 ** case where writable static data is supported, wsdStat can refer directly
 619 ** to the "sqlite3Autoext" state vector declared above.
 620 */
 621 #ifdef SQLITE_OMIT_WSD
 622 # define wsdAutoextInit \
 623   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
 624 # define wsdAutoext x[0]
 625 #else
 626 # define wsdAutoextInit
 627 # define wsdAutoext sqlite3Autoext
 628 #endif
 629
 630
 631 /*
 632 ** Register a statically linked extension that is automatically
 633 ** loaded by every new database connection.
 634 */
 635 int sqlite3_auto_extension(void (*xInit)(void)){
 636   int rc = SQLITE_OK;
 637 #ifndef SQLITE_OMIT_AUTOINIT
 638   rc = sqlite3_initialize();
 639   if( rc ){
 640     return rc;
 641   }else
 642 #endif
 643   {
 644     int i;
 645 #if SQLITE_THREADSAFE
 646     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 647 #endif
 648     wsdAutoextInit;
 649     sqlite3_mutex_enter(mutex);
 650     for(i=0; i<wsdAutoext.nExt; i++){
 651       if( wsdAutoext.aExt[i]==xInit ) break;
 652     }
 653     if( i==wsdAutoext.nExt ){
 654       int nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
 655       void (**aNew)(void);
 656       aNew = sqlite3_realloc(wsdAutoext.aExt, nByte);
 657       if( aNew==0 ){
 658         rc = SQLITE_NOMEM;
 659       }else{
 660         wsdAutoext.aExt = aNew;
 661         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
 662         wsdAutoext.nExt++;
 663       }
 664     }
 665     sqlite3_mutex_leave(mutex);
 666     assert( (rc&0xff)==rc );
 667     return rc;
 668   }
 669 }
 670
 671 /*
 672 ** Reset the automatic extension loading mechanism.
 673 */
 674 void sqlite3_reset_auto_extension(void){
 675 #ifndef SQLITE_OMIT_AUTOINIT
 676   if( sqlite3_initialize()==SQLITE_OK )
 677 #endif
 678   {
 679 #if SQLITE_THREADSAFE
 680     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 681 #endif
 682     wsdAutoextInit;
 683     sqlite3_mutex_enter(mutex);
 684     sqlite3_free(wsdAutoext.aExt);
 685     wsdAutoext.aExt = 0;
 686     wsdAutoext.nExt = 0;
 687     sqlite3_mutex_leave(mutex);
 688   }
 689 }
 690
 691 /*
 692 ** Load all automatic extensions.
 693 **
 694 ** If anything goes wrong, set an error in the database connection.
 695 */
 696 void sqlite3AutoLoadExtensions(sqlite3 *db){
 697   int i;
 698   int go = 1;
 699   int rc;
 700   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
 701
 702   wsdAutoextInit;
 703   if( wsdAutoext.nExt==0 ){
 704     /* Common case: early out without every having to acquire a mutex */
 705     return;
 706   }
 707   for(i=0; go; i++){
 708     char *zErrmsg;
 709 #if SQLITE_THREADSAFE
 710     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 711 #endif
 712     sqlite3_mutex_enter(mutex);
 713     if( i>=wsdAutoext.nExt ){
 714       xInit = 0;
 715       go = 0;
 716     }else{
 717       xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
 718               wsdAutoext.aExt[i];
 719     }
 720     sqlite3_mutex_leave(mutex);
 721     zErrmsg = 0;
 722     if( xInit && (rc = xInit(db, &zErrmsg, &sqlite3Apis))!=0 ){
 723       sqlite3Error(db, rc,
 724             "automatic extension loading failed: %s", zErrmsg);
 725       go = 0;
 726     }
 727     sqlite3_free(zErrmsg);
 728   }
 729 }