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
  22 #ifndef SQLITE_OMIT_LOAD_EXTENSION
  23 /*
  24 ** Some API routines are omitted when various features are
  25 ** excluded from a build of SQLite.  Substitute a NULL pointer
  26 ** for any missing APIs.
  27 */
  28 #ifndef SQLITE_ENABLE_COLUMN_METADATA
  29 # define sqlite3_column_database_name   0
  30 # define sqlite3_column_database_name16 0
  31 # define sqlite3_column_table_name      0
  32 # define sqlite3_column_table_name16    0
  33 # define sqlite3_column_origin_name     0
  34 # define sqlite3_column_origin_name16   0
  35 #endif
  36
  37 #ifdef SQLITE_OMIT_AUTHORIZATION
  38 # define sqlite3_set_authorizer         0
  39 #endif
  40
  41 #ifdef SQLITE_OMIT_UTF16
  42 # define sqlite3_bind_text16            0
  43 # define sqlite3_collation_needed16     0
  44 # define sqlite3_column_decltype16      0
  45 # define sqlite3_column_name16          0
  46 # define sqlite3_column_text16          0
  47 # define sqlite3_complete16             0
  48 # define sqlite3_create_collation16     0
  49 # define sqlite3_create_function16      0
  50 # define sqlite3_errmsg16               0
  51 # define sqlite3_open16                 0
  52 # define sqlite3_prepare16              0
  53 # define sqlite3_prepare16_v2           0
  54 # define sqlite3_prepare16_v3           0
  55 # define sqlite3_result_error16         0
  56 # define sqlite3_result_text16          0
  57 # define sqlite3_result_text16be        0
  58 # define sqlite3_result_text16le        0
  59 # define sqlite3_value_text16           0
  60 # define sqlite3_value_text16be         0
  61 # define sqlite3_value_text16le         0
  62 # define sqlite3_column_database_name16 0
  63 # define sqlite3_column_table_name16    0
  64 # define sqlite3_column_origin_name16   0
  65 #endif
  66
  67 #ifdef SQLITE_OMIT_COMPLETE
  68 # define sqlite3_complete 0
  69 # define sqlite3_complete16 0
  70 #endif
  71
  72 #ifdef SQLITE_OMIT_DECLTYPE
  73 # define sqlite3_column_decltype16      0
  74 # define sqlite3_column_decltype        0
  75 #endif
  76
  77 #ifdef SQLITE_OMIT_PROGRESS_CALLBACK
  78 # define sqlite3_progress_handler 0
  79 #endif
  80
  81 #ifdef SQLITE_OMIT_VIRTUALTABLE
  82 # define sqlite3_create_module 0
  83 # define sqlite3_create_module_v2 0
  84 # define sqlite3_declare_vtab 0
  85 # define sqlite3_vtab_config 0
  86 # define sqlite3_vtab_on_conflict 0
  87 #endif
  88
  89 #ifdef SQLITE_OMIT_SHARED_CACHE
  90 # define sqlite3_enable_shared_cache 0
  91 #endif
  92
  93 #if defined(SQLITE_OMIT_TRACE) || defined(SQLITE_OMIT_DEPRECATED)
  94 # define sqlite3_profile       0
  95 # define sqlite3_trace         0
  96 #endif
  97
  98 #ifdef SQLITE_OMIT_GET_TABLE
  99 # define sqlite3_free_table    0
 100 # define sqlite3_get_table     0
 101 #endif
 102
 103 #ifdef SQLITE_OMIT_INCRBLOB
 104 #define sqlite3_bind_zeroblob  0
 105 #define sqlite3_blob_bytes     0
 106 #define sqlite3_blob_close     0
 107 #define sqlite3_blob_open      0
 108 #define sqlite3_blob_read      0
 109 #define sqlite3_blob_write     0
 110 #define sqlite3_blob_reopen    0
 111 #endif
 112
 113 #if defined(SQLITE_OMIT_TRACE)
 114 # define sqlite3_trace_v2      0
 115 #endif
 116
 117 /*
 118 ** The following structure contains pointers to all SQLite API routines.
 119 ** A pointer to this structure is passed into extensions when they are
 120 ** loaded so that the extension can make calls back into the SQLite
 121 ** library.
 122 **
 123 ** When adding new APIs, add them to the bottom of this structure
 124 ** in order to preserve backwards compatibility.
 125 **
 126 ** Extensions that use newer APIs should first call the
 127 ** sqlite3_libversion_number() to make sure that the API they
 128 ** intend to use is supported by the library.  Extensions should
 129 ** also check to make sure that the pointer to the function is
 130 ** not NULL before calling it.
 131 */
 132 static const sqlite3_api_routines sqlite3Apis = {
 133   sqlite3_aggregate_context,
 134 #ifndef SQLITE_OMIT_DEPRECATED
 135   sqlite3_aggregate_count,
 136 #else
 137   0,
 138 #endif
 139   sqlite3_bind_blob,
 140   sqlite3_bind_double,
 141   sqlite3_bind_int,
 142   sqlite3_bind_int64,
 143   sqlite3_bind_null,
 144   sqlite3_bind_parameter_count,
 145   sqlite3_bind_parameter_index,
 146   sqlite3_bind_parameter_name,
 147   sqlite3_bind_text,
 148   sqlite3_bind_text16,
 149   sqlite3_bind_value,
 150   sqlite3_busy_handler,
 151   sqlite3_busy_timeout,
 152   sqlite3_changes,
 153   sqlite3_close,
 154   sqlite3_collation_needed,
 155   sqlite3_collation_needed16,
 156   sqlite3_column_blob,
 157   sqlite3_column_bytes,
 158   sqlite3_column_bytes16,
 159   sqlite3_column_count,
 160   sqlite3_column_database_name,
 161   sqlite3_column_database_name16,
 162   sqlite3_column_decltype,
 163   sqlite3_column_decltype16,
 164   sqlite3_column_double,
 165   sqlite3_column_int,
 166   sqlite3_column_int64,
 167   sqlite3_column_name,
 168   sqlite3_column_name16,
 169   sqlite3_column_origin_name,
 170   sqlite3_column_origin_name16,
 171   sqlite3_column_table_name,
 172   sqlite3_column_table_name16,
 173   sqlite3_column_text,
 174   sqlite3_column_text16,
 175   sqlite3_column_type,
 176   sqlite3_column_value,
 177   sqlite3_commit_hook,
 178   sqlite3_complete,
 179   sqlite3_complete16,
 180   sqlite3_create_collation,
 181   sqlite3_create_collation16,
 182   sqlite3_create_function,
 183   sqlite3_create_function16,
 184   sqlite3_create_module,
 185   sqlite3_data_count,
 186   sqlite3_db_handle,
 187   sqlite3_declare_vtab,
 188   sqlite3_enable_shared_cache,
 189   sqlite3_errcode,
 190   sqlite3_errmsg,
 191   sqlite3_errmsg16,
 192   sqlite3_exec,
 193 #ifndef SQLITE_OMIT_DEPRECATED
 194   sqlite3_expired,
 195 #else
 196   0,
 197 #endif
 198   sqlite3_finalize,
 199   sqlite3_free,
 200   sqlite3_free_table,
 201   sqlite3_get_autocommit,
 202   sqlite3_get_auxdata,
 203   sqlite3_get_table,
 204   0,     /* Was sqlite3_global_recover(), but that function is deprecated */
 205   sqlite3_interrupt,
 206   sqlite3_last_insert_rowid,
 207   sqlite3_libversion,
 208   sqlite3_libversion_number,
 209   sqlite3_malloc,
 210   sqlite3_mprintf,
 211   sqlite3_open,
 212   sqlite3_open16,
 213   sqlite3_prepare,
 214   sqlite3_prepare16,
 215   sqlite3_profile,
 216   sqlite3_progress_handler,
 217   sqlite3_realloc,
 218   sqlite3_reset,
 219   sqlite3_result_blob,
 220   sqlite3_result_double,
 221   sqlite3_result_error,
 222   sqlite3_result_error16,
 223   sqlite3_result_int,
 224   sqlite3_result_int64,
 225   sqlite3_result_null,
 226   sqlite3_result_text,
 227   sqlite3_result_text16,
 228   sqlite3_result_text16be,
 229   sqlite3_result_text16le,
 230   sqlite3_result_value,
 231   sqlite3_rollback_hook,
 232   sqlite3_set_authorizer,
 233   sqlite3_set_auxdata,
 234   sqlite3_snprintf,
 235   sqlite3_step,
 236   sqlite3_table_column_metadata,
 237 #ifndef SQLITE_OMIT_DEPRECATED
 238   sqlite3_thread_cleanup,
 239 #else
 240   0,
 241 #endif
 242   sqlite3_total_changes,
 243   sqlite3_trace,
 244 #ifndef SQLITE_OMIT_DEPRECATED
 245   sqlite3_transfer_bindings,
 246 #else
 247   0,
 248 #endif
 249   sqlite3_update_hook,
 250   sqlite3_user_data,
 251   sqlite3_value_blob,
 252   sqlite3_value_bytes,
 253   sqlite3_value_bytes16,
 254   sqlite3_value_double,
 255   sqlite3_value_int,
 256   sqlite3_value_int64,
 257   sqlite3_value_numeric_type,
 258   sqlite3_value_text,
 259   sqlite3_value_text16,
 260   sqlite3_value_text16be,
 261   sqlite3_value_text16le,
 262   sqlite3_value_type,
 263   sqlite3_vmprintf,
 264   /*
 265   ** The original API set ends here.  All extensions can call any
 266   ** of the APIs above provided that the pointer is not NULL.  But
 267   ** before calling APIs that follow, extension should check the
 268   ** sqlite3_libversion_number() to make sure they are dealing with
 269   ** a library that is new enough to support that API.
 270   *************************************************************************
 271   */
 272   sqlite3_overload_function,
 273
 274   /*
 275   ** Added after 3.3.13
 276   */
 277   sqlite3_prepare_v2,
 278   sqlite3_prepare16_v2,
 279   sqlite3_clear_bindings,
 280
 281   /*
 282   ** Added for 3.4.1
 283   */
 284   sqlite3_create_module_v2,
 285
 286   /*
 287   ** Added for 3.5.0
 288   */
 289   sqlite3_bind_zeroblob,
 290   sqlite3_blob_bytes,
 291   sqlite3_blob_close,
 292   sqlite3_blob_open,
 293   sqlite3_blob_read,
 294   sqlite3_blob_write,
 295   sqlite3_create_collation_v2,
 296   sqlite3_file_control,
 297   sqlite3_memory_highwater,
 298   sqlite3_memory_used,
 299 #ifdef SQLITE_MUTEX_OMIT
 300   0,
 301   0,
 302   0,
 303   0,
 304   0,
 305 #else
 306   sqlite3_mutex_alloc,
 307   sqlite3_mutex_enter,
 308   sqlite3_mutex_free,
 309   sqlite3_mutex_leave,
 310   sqlite3_mutex_try,
 311 #endif
 312   sqlite3_open_v2,
 313   sqlite3_release_memory,
 314   sqlite3_result_error_nomem,
 315   sqlite3_result_error_toobig,
 316   sqlite3_sleep,
 317   sqlite3_soft_heap_limit,
 318   sqlite3_vfs_find,
 319   sqlite3_vfs_register,
 320   sqlite3_vfs_unregister,
 321
 322   /*
 323   ** Added for 3.5.8
 324   */
 325   sqlite3_threadsafe,
 326   sqlite3_result_zeroblob,
 327   sqlite3_result_error_code,
 328   sqlite3_test_control,
 329   sqlite3_randomness,
 330   sqlite3_context_db_handle,
 331
 332   /*
 333   ** Added for 3.6.0
 334   */
 335   sqlite3_extended_result_codes,
 336   sqlite3_limit,
 337   sqlite3_next_stmt,
 338   sqlite3_sql,
 339   sqlite3_status,
 340
 341   /*
 342   ** Added for 3.7.4
 343   */
 344   sqlite3_backup_finish,
 345   sqlite3_backup_init,
 346   sqlite3_backup_pagecount,
 347   sqlite3_backup_remaining,
 348   sqlite3_backup_step,
 349 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
 350   sqlite3_compileoption_get,
 351   sqlite3_compileoption_used,
 352 #else
 353   0,
 354   0,
 355 #endif
 356   sqlite3_create_function_v2,
 357   sqlite3_db_config,
 358   sqlite3_db_mutex,
 359   sqlite3_db_status,
 360   sqlite3_extended_errcode,
 361   sqlite3_log,
 362   sqlite3_soft_heap_limit64,
 363   sqlite3_sourceid,
 364   sqlite3_stmt_status,
 365   sqlite3_strnicmp,
 366 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
 367   sqlite3_unlock_notify,
 368 #else
 369   0,
 370 #endif
 371 #ifndef SQLITE_OMIT_WAL
 372   sqlite3_wal_autocheckpoint,
 373   sqlite3_wal_checkpoint,
 374   sqlite3_wal_hook,
 375 #else
 376   0,
 377   0,
 378   0,
 379 #endif
 380   sqlite3_blob_reopen,
 381   sqlite3_vtab_config,
 382   sqlite3_vtab_on_conflict,
 383   sqlite3_close_v2,
 384   sqlite3_db_filename,
 385   sqlite3_db_readonly,
 386   sqlite3_db_release_memory,
 387   sqlite3_errstr,
 388   sqlite3_stmt_busy,
 389   sqlite3_stmt_readonly,
 390   sqlite3_stricmp,
 391   sqlite3_uri_boolean,
 392   sqlite3_uri_int64,
 393   sqlite3_uri_parameter,
 394   sqlite3_vsnprintf,
 395   sqlite3_wal_checkpoint_v2,
 396   /* Version 3.8.7 and later */
 397   sqlite3_auto_extension,
 398   sqlite3_bind_blob64,
 399   sqlite3_bind_text64,
 400   sqlite3_cancel_auto_extension,
 401   sqlite3_load_extension,
 402   sqlite3_malloc64,
 403   sqlite3_msize,
 404   sqlite3_realloc64,
 405   sqlite3_reset_auto_extension,
 406   sqlite3_result_blob64,
 407   sqlite3_result_text64,
 408   sqlite3_strglob,
 409   /* Version 3.8.11 and later */
 410   (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
 411   sqlite3_value_free,
 412   sqlite3_result_zeroblob64,
 413   sqlite3_bind_zeroblob64,
 414   /* Version 3.9.0 and later */
 415   sqlite3_value_subtype,
 416   sqlite3_result_subtype,
 417   /* Version 3.10.0 and later */
 418   sqlite3_status64,
 419   sqlite3_strlike,
 420   sqlite3_db_cacheflush,
 421   /* Version 3.12.0 and later */
 422   sqlite3_system_errno,
 423   /* Version 3.14.0 and later */
 424   sqlite3_trace_v2,
 425   sqlite3_expanded_sql,
 426   /* Version 3.18.0 and later */
 427   sqlite3_set_last_insert_rowid,
 428   /* Version 3.20.0 and later */
 429   sqlite3_prepare_v3,
 430   sqlite3_prepare16_v3,
 431   sqlite3_bind_pointer,
 432   sqlite3_result_pointer,
 433   sqlite3_value_pointer,
 434   /* Version 3.22.0 and later */
 435   sqlite3_vtab_nochange,
 436   sqlite3_value_nochange,
 437   sqlite3_vtab_collation
 438 };
 439
 440 /*
 441 ** Attempt to load an SQLite extension library contained in the file
 442 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
 443 ** default entry point name (sqlite3_extension_init) is used.  Use
 444 ** of the default name is recommended.
 445 **
 446 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
 447 **
 448 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
 449 ** error message text.  The calling function should free this memory
 450 ** by calling sqlite3DbFree(db, ).
 451 */
 452 static int sqlite3LoadExtension(
 453   sqlite3 *db,          /* Load the extension into this database connection */
 454   const char *zFile,    /* Name of the shared library containing extension */
 455   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
 456   char **pzErrMsg       /* Put error message here if not 0 */
 457 ){
 458   sqlite3_vfs *pVfs = db->pVfs;
 459   void *handle;
 460   sqlite3_loadext_entry xInit;
 461   char *zErrmsg = 0;
 462   const char *zEntry;
 463   char *zAltEntry = 0;
 464   void **aHandle;
 465   u64 nMsg = 300 + sqlite3Strlen30(zFile);
 466   int ii;
 467   int rc;
 468
 469   /* Shared library endings to try if zFile cannot be loaded as written */
 470   static const char *azEndings[] = {
 471 #if SQLITE_OS_WIN
 472      "dll"
 473 #elif defined(__APPLE__)
 474      "dylib"
 475 #else
 476      "so"
 477 #endif
 478   };
 479
 480
 481   if( pzErrMsg ) *pzErrMsg = 0;
 482
 483   /* Ticket #1863.  To avoid a creating security problems for older
 484   ** applications that relink against newer versions of SQLite, the
 485   ** ability to run load_extension is turned off by default.  One
 486   ** must call either sqlite3_enable_load_extension(db) or
 487   ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
 488   ** to turn on extension loading.
 489   */
 490   if( (db->flags & SQLITE_LoadExtension)==0 ){
 491     if( pzErrMsg ){
 492       *pzErrMsg = sqlite3_mprintf("not authorized");
 493     }
 494     return SQLITE_ERROR;
 495   }
 496
 497   zEntry = zProc ? zProc : "sqlite3_extension_init";
 498
 499   handle = sqlite3OsDlOpen(pVfs, zFile);
 500 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
 501   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
 502     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
 503     int bExists = 0;
 504     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
 505     sqlite3OsAccess(pVfs, zAltFile, SQLITE_ACCESS_EXISTS, &bExists);
 506     if( bExists )  handle = sqlite3OsDlOpen(pVfs, zAltFile);
 507     sqlite3_free(zAltFile);
 508   }
 509 #endif
 510   if( handle==0 ){
 511     if( pzErrMsg ){
 512       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
 513       if( zErrmsg ){
 514         sqlite3_snprintf(nMsg, zErrmsg,
 515             "unable to open shared library [%s]", zFile);
 516         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
 517       }
 518     }
 519     return SQLITE_ERROR;
 520   }
 521   xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
 522
 523   /* If no entry point was specified and the default legacy
 524   ** entry point name "sqlite3_extension_init" was not found, then
 525   ** construct an entry point name "sqlite3_X_init" where the X is
 526   ** replaced by the lowercase value of every ASCII alphabetic
 527   ** character in the filename after the last "/" upto the first ".",
 528   ** and eliding the first three characters if they are "lib".
 529   ** Examples:
 530   **
 531   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
 532   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
 533   */
 534   if( xInit==0 && zProc==0 ){
 535     int iFile, iEntry, c;
 536     int ncFile = sqlite3Strlen30(zFile);
 537     zAltEntry = sqlite3_malloc64(ncFile+30);
 538     if( zAltEntry==0 ){
 539       sqlite3OsDlClose(pVfs, handle);
 540       return SQLITE_NOMEM_BKPT;
 541     }
 542     memcpy(zAltEntry, "sqlite3_", 8);
 543     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
 544     iFile++;
 545     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
 546     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
 547       if( sqlite3Isalpha(c) ){
 548         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
 549       }
 550     }
 551     memcpy(zAltEntry+iEntry, "_init", 6);
 552     zEntry = zAltEntry;
 553     xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
 554   }
 555   if( xInit==0 ){
 556     if( pzErrMsg ){
 557       nMsg += sqlite3Strlen30(zEntry);
 558       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
 559       if( zErrmsg ){
 560         sqlite3_snprintf(nMsg, zErrmsg,
 561             "no entry point [%s] in shared library [%s]", zEntry, zFile);
 562         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
 563       }
 564     }
 565     sqlite3OsDlClose(pVfs, handle);
 566     sqlite3_free(zAltEntry);
 567     return SQLITE_ERROR;
 568   }
 569   sqlite3_free(zAltEntry);
 570   rc = xInit(db, &zErrmsg, &sqlite3Apis);
 571   if( rc ){
 572     if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
 573     if( pzErrMsg ){
 574       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
 575     }
 576     sqlite3_free(zErrmsg);
 577     sqlite3OsDlClose(pVfs, handle);
 578     return SQLITE_ERROR;
 579   }
 580
 581   /* Append the new shared library handle to the db->aExtension array. */
 582   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
 583   if( aHandle==0 ){
 584     return SQLITE_NOMEM_BKPT;
 585   }
 586   if( db->nExtension>0 ){
 587     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
 588   }
 589   sqlite3DbFree(db, db->aExtension);
 590   db->aExtension = aHandle;
 591
 592   db->aExtension[db->nExtension++] = handle;
 593   return SQLITE_OK;
 594 }
 595 int sqlite3_load_extension(
 596   sqlite3 *db,          /* Load the extension into this database connection */
 597   const char *zFile,    /* Name of the shared library containing extension */
 598   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
 599   char **pzErrMsg       /* Put error message here if not 0 */
 600 ){
 601   int rc;
 602   sqlite3_mutex_enter(db->mutex);
 603   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
 604   rc = sqlite3ApiExit(db, rc);
 605   sqlite3_mutex_leave(db->mutex);
 606   return rc;
 607 }
 608
 609 /*
 610 ** Call this routine when the database connection is closing in order
 611 ** to clean up loaded extensions
 612 */
 613 void sqlite3CloseExtensions(sqlite3 *db){
 614   int i;
 615   assert( sqlite3_mutex_held(db->mutex) );
 616   for(i=0; i<db->nExtension; i++){
 617     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
 618   }
 619   sqlite3DbFree(db, db->aExtension);
 620 }
 621
 622 /*
 623 ** Enable or disable extension loading.  Extension loading is disabled by
 624 ** default so as not to open security holes in older applications.
 625 */
 626 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
 627   sqlite3_mutex_enter(db->mutex);
 628   if( onoff ){
 629     db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
 630   }else{
 631     db->flags &= ~(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
 632   }
 633   sqlite3_mutex_leave(db->mutex);
 634   return SQLITE_OK;
 635 }
 636
 637 #endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
 638
 639 /*
 640 ** The following object holds the list of automatically loaded
 641 ** extensions.
 642 **
 643 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
 644 ** mutex must be held while accessing this list.
 645 */
 646 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
 647 static SQLITE_WSD struct sqlite3AutoExtList {
 648   u32 nExt;              /* Number of entries in aExt[] */
 649   void (**aExt)(void);   /* Pointers to the extension init functions */
 650 } sqlite3Autoext = { 0, 0 };
 651
 652 /* The "wsdAutoext" macro will resolve to the autoextension
 653 ** state vector.  If writable static data is unsupported on the target,
 654 ** we have to locate the state vector at run-time.  In the more common
 655 ** case where writable static data is supported, wsdStat can refer directly
 656 ** to the "sqlite3Autoext" state vector declared above.
 657 */
 658 #ifdef SQLITE_OMIT_WSD
 659 # define wsdAutoextInit \
 660   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
 661 # define wsdAutoext x[0]
 662 #else
 663 # define wsdAutoextInit
 664 # define wsdAutoext sqlite3Autoext
 665 #endif
 666
 667
 668 /*
 669 ** Register a statically linked extension that is automatically
 670 ** loaded by every new database connection.
 671 */
 672 int sqlite3_auto_extension(
 673   void (*xInit)(void)
 674 ){
 675   int rc = SQLITE_OK;
 676 #ifndef SQLITE_OMIT_AUTOINIT
 677   rc = sqlite3_initialize();
 678   if( rc ){
 679     return rc;
 680   }else
 681 #endif
 682   {
 683     u32 i;
 684 #if SQLITE_THREADSAFE
 685     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 686 #endif
 687     wsdAutoextInit;
 688     sqlite3_mutex_enter(mutex);
 689     for(i=0; i<wsdAutoext.nExt; i++){
 690       if( wsdAutoext.aExt[i]==xInit ) break;
 691     }
 692     if( i==wsdAutoext.nExt ){
 693       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
 694       void (**aNew)(void);
 695       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
 696       if( aNew==0 ){
 697         rc = SQLITE_NOMEM_BKPT;
 698       }else{
 699         wsdAutoext.aExt = aNew;
 700         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
 701         wsdAutoext.nExt++;
 702       }
 703     }
 704     sqlite3_mutex_leave(mutex);
 705     assert( (rc&0xff)==rc );
 706     return rc;
 707   }
 708 }
 709
 710 /*
 711 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
 712 ** set of routines that is invoked for each new database connection, if it
 713 ** is currently on the list.  If xInit is not on the list, then this
 714 ** routine is a no-op.
 715 **
 716 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
 717 ** was not on the list.
 718 */
 719 int sqlite3_cancel_auto_extension(
 720   void (*xInit)(void)
 721 ){
 722 #if SQLITE_THREADSAFE
 723   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 724 #endif
 725   int i;
 726   int n = 0;
 727   wsdAutoextInit;
 728   sqlite3_mutex_enter(mutex);
 729   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
 730     if( wsdAutoext.aExt[i]==xInit ){
 731       wsdAutoext.nExt--;
 732       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
 733       n++;
 734       break;
 735     }
 736   }
 737   sqlite3_mutex_leave(mutex);
 738   return n;
 739 }
 740
 741 /*
 742 ** Reset the automatic extension loading mechanism.
 743 */
 744 void sqlite3_reset_auto_extension(void){
 745 #ifndef SQLITE_OMIT_AUTOINIT
 746   if( sqlite3_initialize()==SQLITE_OK )
 747 #endif
 748   {
 749 #if SQLITE_THREADSAFE
 750     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 751 #endif
 752     wsdAutoextInit;
 753     sqlite3_mutex_enter(mutex);
 754     sqlite3_free(wsdAutoext.aExt);
 755     wsdAutoext.aExt = 0;
 756     wsdAutoext.nExt = 0;
 757     sqlite3_mutex_leave(mutex);
 758   }
 759 }
 760
 761 /*
 762 ** Load all automatic extensions.
 763 **
 764 ** If anything goes wrong, set an error in the database connection.
 765 */
 766 void sqlite3AutoLoadExtensions(sqlite3 *db){
 767   u32 i;
 768   int go = 1;
 769   int rc;
 770   sqlite3_loadext_entry xInit;
 771
 772   wsdAutoextInit;
 773   if( wsdAutoext.nExt==0 ){
 774     /* Common case: early out without every having to acquire a mutex */
 775     return;
 776   }
 777   for(i=0; go; i++){
 778     char *zErrmsg;
 779 #if SQLITE_THREADSAFE
 780     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
 781 #endif
 782 #ifdef SQLITE_OMIT_LOAD_EXTENSION
 783     const sqlite3_api_routines *pThunk = 0;
 784 #else
 785     const sqlite3_api_routines *pThunk = &sqlite3Apis;
 786 #endif
 787     sqlite3_mutex_enter(mutex);
 788     if( i>=wsdAutoext.nExt ){
 789       xInit = 0;
 790       go = 0;
 791     }else{
 792       xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
 793     }
 794     sqlite3_mutex_leave(mutex);
 795     zErrmsg = 0;
 796     if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
 797       sqlite3ErrorWithMsg(db, rc,
 798             "automatic extension loading failed: %s", zErrmsg);
 799       go = 0;
 800     }
 801     sqlite3_free(zErrmsg);
 802   }
 803 }