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 # define sqlite3_vtab_collation 0
  88 #endif
  89
  90 #ifdef SQLITE_OMIT_SHARED_CACHE
  91 # define sqlite3_enable_shared_cache 0
  92 #endif
  93
  94 #if defined(SQLITE_OMIT_TRACE) || defined(SQLITE_OMIT_DEPRECATED)
  95 # define sqlite3_profile       0
  96 # define sqlite3_trace         0
  97 #endif
  98
  99 #ifdef SQLITE_OMIT_GET_TABLE
 100 # define sqlite3_free_table    0
 101 # define sqlite3_get_table     0
 102 #endif
 103
 104 #ifdef SQLITE_OMIT_INCRBLOB
 105 #define sqlite3_bind_zeroblob  0
 106 #define sqlite3_blob_bytes     0
 107 #define sqlite3_blob_close     0
 108 #define sqlite3_blob_open      0
 109 #define sqlite3_blob_read      0
 110 #define sqlite3_blob_write     0
 111 #define sqlite3_blob_reopen    0
 112 #endif
 113
 114 #if defined(SQLITE_OMIT_TRACE)
 115 # define sqlite3_trace_v2      0
 116 #endif
 117
 118 /*
 119 ** The following structure contains pointers to all SQLite API routines.
 120 ** A pointer to this structure is passed into extensions when they are
 121 ** loaded so that the extension can make calls back into the SQLite
 122 ** library.
 123 **
 124 ** When adding new APIs, add them to the bottom of this structure
 125 ** in order to preserve backwards compatibility.
 126 **
 127 ** Extensions that use newer APIs should first call the
 128 ** sqlite3_libversion_number() to make sure that the API they
 129 ** intend to use is supported by the library.  Extensions should
 130 ** also check to make sure that the pointer to the function is
 131 ** not NULL before calling it.
 132 */
 133 static const sqlite3_api_routines sqlite3Apis = {
 134   sqlite3_aggregate_context,
 135 #ifndef SQLITE_OMIT_DEPRECATED
 136   sqlite3_aggregate_count,
 137 #else
 138   0,
 139 #endif
 140   sqlite3_bind_blob,
 141   sqlite3_bind_double,
 142   sqlite3_bind_int,
 143   sqlite3_bind_int64,
 144   sqlite3_bind_null,
 145   sqlite3_bind_parameter_count,
 146   sqlite3_bind_parameter_index,
 147   sqlite3_bind_parameter_name,
 148   sqlite3_bind_text,
 149   sqlite3_bind_text16,
 150   sqlite3_bind_value,
 151   sqlite3_busy_handler,
 152   sqlite3_busy_timeout,
 153   sqlite3_changes,
 154   sqlite3_close,
 155   sqlite3_collation_needed,
 156   sqlite3_collation_needed16,
 157   sqlite3_column_blob,
 158   sqlite3_column_bytes,
 159   sqlite3_column_bytes16,
 160   sqlite3_column_count,
 161   sqlite3_column_database_name,
 162   sqlite3_column_database_name16,
 163   sqlite3_column_decltype,
 164   sqlite3_column_decltype16,
 165   sqlite3_column_double,
 166   sqlite3_column_int,
 167   sqlite3_column_int64,
 168   sqlite3_column_name,
 169   sqlite3_column_name16,
 170   sqlite3_column_origin_name,
 171   sqlite3_column_origin_name16,
 172   sqlite3_column_table_name,
 173   sqlite3_column_table_name16,
 174   sqlite3_column_text,
 175   sqlite3_column_text16,
 176   sqlite3_column_type,
 177   sqlite3_column_value,
 178   sqlite3_commit_hook,
 179   sqlite3_complete,
 180   sqlite3_complete16,
 181   sqlite3_create_collation,
 182   sqlite3_create_collation16,
 183   sqlite3_create_function,
 184   sqlite3_create_function16,
 185   sqlite3_create_module,
 186   sqlite3_data_count,
 187   sqlite3_db_handle,
 188   sqlite3_declare_vtab,
 189   sqlite3_enable_shared_cache,
 190   sqlite3_errcode,
 191   sqlite3_errmsg,
 192   sqlite3_errmsg16,
 193   sqlite3_exec,
 194 #ifndef SQLITE_OMIT_DEPRECATED
 195   sqlite3_expired,
 196 #else
 197   0,
 198 #endif
 199   sqlite3_finalize,
 200   sqlite3_free,
 201   sqlite3_free_table,
 202   sqlite3_get_autocommit,
 203   sqlite3_get_auxdata,
 204   sqlite3_get_table,
 205   0,     /* Was sqlite3_global_recover(), but that function is deprecated */
 206   sqlite3_interrupt,
 207   sqlite3_last_insert_rowid,
 208   sqlite3_libversion,
 209   sqlite3_libversion_number,
 210   sqlite3_malloc,
 211   sqlite3_mprintf,
 212   sqlite3_open,
 213   sqlite3_open16,
 214   sqlite3_prepare,
 215   sqlite3_prepare16,
 216   sqlite3_profile,
 217   sqlite3_progress_handler,
 218   sqlite3_realloc,
 219   sqlite3_reset,
 220   sqlite3_result_blob,
 221   sqlite3_result_double,
 222   sqlite3_result_error,
 223   sqlite3_result_error16,
 224   sqlite3_result_int,
 225   sqlite3_result_int64,
 226   sqlite3_result_null,
 227   sqlite3_result_text,
 228   sqlite3_result_text16,
 229   sqlite3_result_text16be,
 230   sqlite3_result_text16le,
 231   sqlite3_result_value,
 232   sqlite3_rollback_hook,
 233   sqlite3_set_authorizer,
 234   sqlite3_set_auxdata,
 235   sqlite3_snprintf,
 236   sqlite3_step,
 237   sqlite3_table_column_metadata,
 238 #ifndef SQLITE_OMIT_DEPRECATED
 239   sqlite3_thread_cleanup,
 240 #else
 241   0,
 242 #endif
 243   sqlite3_total_changes,
 244   sqlite3_trace,
 245 #ifndef SQLITE_OMIT_DEPRECATED
 246   sqlite3_transfer_bindings,
 247 #else
 248   0,
 249 #endif
 250   sqlite3_update_hook,
 251   sqlite3_user_data,
 252   sqlite3_value_blob,
 253   sqlite3_value_bytes,
 254   sqlite3_value_bytes16,
 255   sqlite3_value_double,
 256   sqlite3_value_int,
 257   sqlite3_value_int64,
 258   sqlite3_value_numeric_type,
 259   sqlite3_value_text,
 260   sqlite3_value_text16,
 261   sqlite3_value_text16be,
 262   sqlite3_value_text16le,
 263   sqlite3_value_type,
 264   sqlite3_vmprintf,
 265   /*
 266   ** The original API set ends here.  All extensions can call any
 267   ** of the APIs above provided that the pointer is not NULL.  But
 268   ** before calling APIs that follow, extension should check the
 269   ** sqlite3_libversion_number() to make sure they are dealing with
 270   ** a library that is new enough to support that API.
 271   *************************************************************************
 272   */
 273   sqlite3_overload_function,
 274
 275   /*
 276   ** Added after 3.3.13
 277   */
 278   sqlite3_prepare_v2,
 279   sqlite3_prepare16_v2,
 280   sqlite3_clear_bindings,
 281
 282   /*
 283   ** Added for 3.4.1
 284   */
 285   sqlite3_create_module_v2,
 286
 287   /*
 288   ** Added for 3.5.0
 289   */
 290   sqlite3_bind_zeroblob,
 291   sqlite3_blob_bytes,
 292   sqlite3_blob_close,
 293   sqlite3_blob_open,
 294   sqlite3_blob_read,
 295   sqlite3_blob_write,
 296   sqlite3_create_collation_v2,
 297   sqlite3_file_control,
 298   sqlite3_memory_highwater,
 299   sqlite3_memory_used,
 300 #ifdef SQLITE_MUTEX_OMIT
 301   0,
 302   0,
 303   0,
 304   0,
 305   0,
 306 #else
 307   sqlite3_mutex_alloc,
 308   sqlite3_mutex_enter,
 309   sqlite3_mutex_free,
 310   sqlite3_mutex_leave,
 311   sqlite3_mutex_try,
 312 #endif
 313   sqlite3_open_v2,
 314   sqlite3_release_memory,
 315   sqlite3_result_error_nomem,
 316   sqlite3_result_error_toobig,
 317   sqlite3_sleep,
 318   sqlite3_soft_heap_limit,
 319   sqlite3_vfs_find,
 320   sqlite3_vfs_register,
 321   sqlite3_vfs_unregister,
 322
 323   /*
 324   ** Added for 3.5.8
 325   */
 326   sqlite3_threadsafe,
 327   sqlite3_result_zeroblob,
 328   sqlite3_result_error_code,
 329   sqlite3_test_control,
 330   sqlite3_randomness,
 331   sqlite3_context_db_handle,
 332
 333   /*
 334   ** Added for 3.6.0
 335   */
 336   sqlite3_extended_result_codes,
 337   sqlite3_limit,
 338   sqlite3_next_stmt,
 339   sqlite3_sql,
 340   sqlite3_status,
 341
 342   /*
 343   ** Added for 3.7.4
 344   */
 345   sqlite3_backup_finish,
 346   sqlite3_backup_init,
 347   sqlite3_backup_pagecount,
 348   sqlite3_backup_remaining,
 349   sqlite3_backup_step,
 350 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
 351   sqlite3_compileoption_get,
 352   sqlite3_compileoption_used,
 353 #else
 354   0,
 355   0,
 356 #endif
 357   sqlite3_create_function_v2,
 358   sqlite3_db_config,
 359   sqlite3_db_mutex,
 360   sqlite3_db_status,
 361   sqlite3_extended_errcode,
 362   sqlite3_log,
 363   sqlite3_soft_heap_limit64,
 364   sqlite3_sourceid,
 365   sqlite3_stmt_status,
 366   sqlite3_strnicmp,
 367 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
 368   sqlite3_unlock_notify,
 369 #else
 370   0,
 371 #endif
 372 #ifndef SQLITE_OMIT_WAL
 373   sqlite3_wal_autocheckpoint,
 374   sqlite3_wal_checkpoint,
 375   sqlite3_wal_hook,
 376 #else
 377   0,
 378   0,
 379   0,
 380 #endif
 381   sqlite3_blob_reopen,
 382   sqlite3_vtab_config,
 383   sqlite3_vtab_on_conflict,
 384   sqlite3_close_v2,
 385   sqlite3_db_filename,
 386   sqlite3_db_readonly,
 387   sqlite3_db_release_memory,
 388   sqlite3_errstr,
 389   sqlite3_stmt_busy,
 390   sqlite3_stmt_readonly,
 391   sqlite3_stricmp,
 392   sqlite3_uri_boolean,
 393   sqlite3_uri_int64,
 394   sqlite3_uri_parameter,
 395   sqlite3_vsnprintf,
 396   sqlite3_wal_checkpoint_v2,
 397   /* Version 3.8.7 and later */
 398   sqlite3_auto_extension,
 399   sqlite3_bind_blob64,
 400   sqlite3_bind_text64,
 401   sqlite3_cancel_auto_extension,
 402   sqlite3_load_extension,
 403   sqlite3_malloc64,
 404   sqlite3_msize,
 405   sqlite3_realloc64,
 406   sqlite3_reset_auto_extension,
 407   sqlite3_result_blob64,
 408   sqlite3_result_text64,
 409   sqlite3_strglob,
 410   /* Version 3.8.11 and later */
 411   (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
 412   sqlite3_value_free,
 413   sqlite3_result_zeroblob64,
 414   sqlite3_bind_zeroblob64,
 415   /* Version 3.9.0 and later */
 416   sqlite3_value_subtype,
 417   sqlite3_result_subtype,
 418   /* Version 3.10.0 and later */
 419   sqlite3_status64,
 420   sqlite3_strlike,
 421   sqlite3_db_cacheflush,
 422   /* Version 3.12.0 and later */
 423   sqlite3_system_errno,
 424   /* Version 3.14.0 and later */
 425   sqlite3_trace_v2,
 426   sqlite3_expanded_sql,
 427   /* Version 3.18.0 and later */
 428   sqlite3_set_last_insert_rowid,
 429   /* Version 3.20.0 and later */
 430   sqlite3_prepare_v3,
 431   sqlite3_prepare16_v3,
 432   sqlite3_bind_pointer,
 433   sqlite3_result_pointer,
 434   sqlite3_value_pointer,
 435   /* Version 3.22.0 and later */
 436   sqlite3_vtab_nochange,
 437   sqlite3_value_nochange,
 438   sqlite3_vtab_collation,
 439   /* Version 3.24.0 and later */
 440   sqlite3_keyword_count,
 441   sqlite3_keyword_name,
 442   sqlite3_keyword_check,
 443   sqlite3_str_new,
 444   sqlite3_str_finish,
 445   sqlite3_str_appendf,
 446   sqlite3_str_vappendf,
 447   sqlite3_str_append,
 448   sqlite3_str_appendall,
 449   sqlite3_str_appendchar,
 450   sqlite3_str_reset,
 451   sqlite3_str_errcode,
 452   sqlite3_str_length,
 453   sqlite3_str_value,
 454   /* Version 3.25.0 and later */
 455   sqlite3_create_window_function,
 456   /* Version 3.26.0 and later */
 457 #ifdef SQLITE_ENABLE_NORMALIZE
 458   sqlite3_normalized_sql,
 459 #else
 460   0,
 461 #endif
 462   /* Version 3.28.0 and later */
 463   sqlite3_stmt_isexplain,
 464   sqlite3_value_frombind,
 465   /* Version 3.30.0 and later */
 466 #ifndef SQLITE_OMIT_VIRTUALTABLE
 467   sqlite3_drop_modules,
 468 #else
 469   0,
 470 #endif
 471   /* Version 3.31.0 and later */
 472   sqlite3_hard_heap_limit64,
 473   sqlite3_uri_key,
 474   sqlite3_filename_database,
 475   sqlite3_filename_journal,
 476   sqlite3_filename_wal,
 477   /* Version 3.32.0 and later */
 478   sqlite3_create_filename,
 479   sqlite3_free_filename,
 480   sqlite3_database_file_object,
 481   /* Version 3.34.0 and later */
 482   sqlite3_txn_state,
 483   /* Version 3.36.1 and later */
 484   sqlite3_changes64,
 485   sqlite3_total_changes64,
 486   /* Version 3.37.0 and later */
 487   sqlite3_autovacuum_pages,
 488   /* Version 3.38.0 and later */
 489   sqlite3_error_offset,
 490 #ifndef SQLITE_OMIT_VIRTUALTABLE
 491   sqlite3_vtab_rhs_value,
 492   sqlite3_vtab_distinct,
 493   sqlite3_vtab_in,
 494   sqlite3_vtab_in_first,
 495   sqlite3_vtab_in_next,
 496 #else
 497   0,
 498   0,
 499   0,
 500   0,
 501   0,
 502 #endif
 503   /* Version 3.39.0 and later */
 504 #ifndef SQLITE_OMIT_DESERIALIZE
 505   sqlite3_deserialize,
 506   sqlite3_serialize,
 507 #else
 508   0,
 509   0,
 510 #endif
 511   sqlite3_db_name,
 512   /* Version 3.40.0 and later */
 513   sqlite3_value_encoding,
 514   /* Version 3.41.0 and later */
 515   sqlite3_is_interrupted
 516 };
 517
 518 /* True if x is the directory separator character
 519 */
 520 #if SQLITE_OS_WIN
 521 # define DirSep(X)  ((X)=='/'||(X)=='\\')
 522 #else
 523 # define DirSep(X)  ((X)=='/')
 524 #endif
 525
 526 /*
 527 ** Attempt to load an SQLite extension library contained in the file
 528 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
 529 ** default entry point name (sqlite3_extension_init) is used.  Use
 530 ** of the default name is recommended.
 531 **
 532 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
 533 **
 534 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
 535 ** error message text.  The calling function should free this memory
 536 ** by calling sqlite3DbFree(db, ).
 537 */
 538 static int sqlite3LoadExtension(
 539   sqlite3 *db,          /* Load the extension into this database connection */
 540   const char *zFile,    /* Name of the shared library containing extension */
 541   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
 542   char **pzErrMsg       /* Put error message here if not 0 */
 543 ){
 544   sqlite3_vfs *pVfs = db->pVfs;
 545   void *handle;
 546   sqlite3_loadext_entry xInit;
 547   char *zErrmsg = 0;
 548   const char *zEntry;
 549   char *zAltEntry = 0;
 550   void **aHandle;
 551   u64 nMsg = strlen(zFile);
 552   int ii;
 553   int rc;
 554
 555   /* Shared library endings to try if zFile cannot be loaded as written */
 556   static const char *azEndings[] = {
 557 #if SQLITE_OS_WIN
 558      "dll"
 559 #elif defined(__APPLE__)
 560      "dylib"
 561 #else
 562      "so"
 563 #endif
 564   };
 565
 566
 567   if( pzErrMsg ) *pzErrMsg = 0;
 568
 569   /* Ticket #1863.  To avoid a creating security problems for older
 570   ** applications that relink against newer versions of SQLite, the
 571   ** ability to run load_extension is turned off by default.  One
 572   ** must call either sqlite3_enable_load_extension(db) or
 573   ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
 574   ** to turn on extension loading.
 575   */
 576   if( (db->flags & SQLITE_LoadExtension)==0 ){
 577     if( pzErrMsg ){
 578       *pzErrMsg = sqlite3_mprintf("not authorized");
 579     }
 580     return SQLITE_ERROR;
 581   }
 582
 583   zEntry = zProc ? zProc : "sqlite3_extension_init";
 584
 585   /* tag-20210611-1.  Some dlopen() implementations will segfault if given
 586   ** an oversize filename.  Most filesystems have a pathname limit of 4K,
 587   ** so limit the extension filename length to about twice that.
 588   ** https://sqlite.org/forum/forumpost/08a0d6d9bf */
 589   if( nMsg>SQLITE_MAX_PATHLEN ) goto extension_not_found;
 590
 591   handle = sqlite3OsDlOpen(pVfs, zFile);
 592 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
 593   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
 594     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
 595     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
 596     handle = sqlite3OsDlOpen(pVfs, zAltFile);
 597     sqlite3_free(zAltFile);
 598   }
 599 #endif
 600   if( handle==0 ) goto extension_not_found;
 601   xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
 602
 603   /* If no entry point was specified and the default legacy
 604   ** entry point name "sqlite3_extension_init" was not found, then
 605   ** construct an entry point name "sqlite3_X_init" where the X is
 606   ** replaced by the lowercase value of every ASCII alphabetic
 607   ** character in the filename after the last "/" upto the first ".",
 608   ** and eliding the first three characters if they are "lib".
 609   ** Examples:
 610   **
 611   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
 612   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
 613   */
 614   if( xInit==0 && zProc==0 ){
 615     int iFile, iEntry, c;
 616     int ncFile = sqlite3Strlen30(zFile);
 617     zAltEntry = sqlite3_malloc64(ncFile+30);
 618     if( zAltEntry==0 ){
 619       sqlite3OsDlClose(pVfs, handle);
 620       return SQLITE_NOMEM_BKPT;
 621     }
 622     memcpy(zAltEntry, "sqlite3_", 8);
 623     for(iFile=ncFile-1; iFile>=0 && !DirSep(zFile[iFile]); iFile--){}
 624     iFile++;
 625     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
 626     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
 627       if( sqlite3Isalpha(c) ){
 628         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
 629       }
 630     }
 631     memcpy(zAltEntry+iEntry, "_init", 6);
 632     zEntry = zAltEntry;
 633     xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
 634   }
 635   if( xInit==0 ){
 636     if( pzErrMsg ){
 637       nMsg += strlen(zEntry) + 300;
 638       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
 639       if( zErrmsg ){
 640         assert( nMsg<0x7fffffff );  /* zErrmsg would be NULL if not so */
 641         sqlite3_snprintf((int)nMsg, zErrmsg,
 642             "no entry point [%s] in shared library [%s]", zEntry, zFile);
 643         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
 644       }
 645     }
 646     sqlite3OsDlClose(pVfs, handle);
 647     sqlite3_free(zAltEntry);
 648     return SQLITE_ERROR;
 649   }
 650   sqlite3_free(zAltEntry);
 651   rc = xInit(db, &zErrmsg, &sqlite3Apis);
 652   if( rc ){
 653     if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
 654     if( pzErrMsg ){
 655       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
 656     }
 657     sqlite3_free(zErrmsg);
 658     sqlite3OsDlClose(pVfs, handle);
 659     return SQLITE_ERROR;
 660   }
 661
 662   /* Append the new shared library handle to the db->aExtension array. */
 663   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
 664   if( aHandle==0 ){
 665     return SQLITE_NOMEM_BKPT;
 666   }
 667   if( db->nExtension>0 ){
 668     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
 669   }
 670   sqlite3DbFree(db, db->aExtension);
 671   db->aExtension = aHandle;
 672
 673   db->aExtension[db->nExtension++] = handle;
 674   return SQLITE_OK;
 675
 676 extension_not_found:
 677   if( pzErrMsg ){
 678     nMsg += 300;
 679     *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
 680     if( zErrmsg ){
 681       assert( nMsg<0x7fffffff );  /* zErrmsg would be NULL if not so */
 682       sqlite3_snprintf((int)nMsg, zErrmsg,
 683           "unable to open shared library [%.*s]", SQLITE_MAX_PATHLEN, zFile);
 684       sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
 685     }
 686   }
 687   return SQLITE_ERROR;
 688 }
 689 int sqlite3_load_extension(
 690   sqlite3 *db,          /* Load the extension into this database connection */
 691   const char *zFile,    /* Name of the shared library containing extension */
 692   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
 693   char **pzErrMsg       /* Put error message here if not 0 */
 694 ){
 695   int rc;
 696   sqlite3_mutex_enter(db->mutex);
 697   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
 698   rc = sqlite3ApiExit(db, rc);
 699   sqlite3_mutex_leave(db->mutex);
 700   return rc;
 701 }
 702
 703 /*
 704 ** Call this routine when the database connection is closing in order
 705 ** to clean up loaded extensions
 706 */
 707 void sqlite3CloseExtensions(sqlite3 *db){
 708   int i;
 709   assert( sqlite3_mutex_held(db->mutex) );
 710   for(i=0; i<db->nExtension; i++){
 711     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
 712   }
 713   sqlite3DbFree(db, db->aExtension);
 714 }
 715
 716 /*
 717 ** Enable or disable extension loading.  Extension loading is disabled by
 718 ** default so as not to open security holes in older applications.
 719 */
 720 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
 721   sqlite3_mutex_enter(db->mutex);
 722   if( onoff ){
 723     db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
 724   }else{
 725     db->flags &= ~(u64)(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
 726   }
 727   sqlite3_mutex_leave(db->mutex);
 728   return SQLITE_OK;
 729 }
 730
 731 #endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
 732
 733 /*
 734 ** The following object holds the list of automatically loaded
 735 ** extensions.
 736 **
 737 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MAIN
 738 ** mutex must be held while accessing this list.
 739 */
 740 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
 741 static SQLITE_WSD struct sqlite3AutoExtList {
 742   u32 nExt;              /* Number of entries in aExt[] */
 743   void (**aExt)(void);   /* Pointers to the extension init functions */
 744 } sqlite3Autoext = { 0, 0 };
 745
 746 /* The "wsdAutoext" macro will resolve to the autoextension
 747 ** state vector.  If writable static data is unsupported on the target,
 748 ** we have to locate the state vector at run-time.  In the more common
 749 ** case where writable static data is supported, wsdStat can refer directly
 750 ** to the "sqlite3Autoext" state vector declared above.
 751 */
 752 #ifdef SQLITE_OMIT_WSD
 753 # define wsdAutoextInit \
 754   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
 755 # define wsdAutoext x[0]
 756 #else
 757 # define wsdAutoextInit
 758 # define wsdAutoext sqlite3Autoext
 759 #endif
 760
 761
 762 /*
 763 ** Register a statically linked extension that is automatically
 764 ** loaded by every new database connection.
 765 */
 766 int sqlite3_auto_extension(
 767   void (*xInit)(void)
 768 ){
 769   int rc = SQLITE_OK;
 770 #ifndef SQLITE_OMIT_AUTOINIT
 771   rc = sqlite3_initialize();
 772   if( rc ){
 773     return rc;
 774   }else
 775 #endif
 776   {
 777     u32 i;
 778 #if SQLITE_THREADSAFE
 779     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
 780 #endif
 781     wsdAutoextInit;
 782     sqlite3_mutex_enter(mutex);
 783     for(i=0; i<wsdAutoext.nExt; i++){
 784       if( wsdAutoext.aExt[i]==xInit ) break;
 785     }
 786     if( i==wsdAutoext.nExt ){
 787       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
 788       void (**aNew)(void);
 789       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
 790       if( aNew==0 ){
 791         rc = SQLITE_NOMEM_BKPT;
 792       }else{
 793         wsdAutoext.aExt = aNew;
 794         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
 795         wsdAutoext.nExt++;
 796       }
 797     }
 798     sqlite3_mutex_leave(mutex);
 799     assert( (rc&0xff)==rc );
 800     return rc;
 801   }
 802 }
 803
 804 /*
 805 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
 806 ** set of routines that is invoked for each new database connection, if it
 807 ** is currently on the list.  If xInit is not on the list, then this
 808 ** routine is a no-op.
 809 **
 810 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
 811 ** was not on the list.
 812 */
 813 int sqlite3_cancel_auto_extension(
 814   void (*xInit)(void)
 815 ){
 816 #if SQLITE_THREADSAFE
 817   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
 818 #endif
 819   int i;
 820   int n = 0;
 821   wsdAutoextInit;
 822   sqlite3_mutex_enter(mutex);
 823   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
 824     if( wsdAutoext.aExt[i]==xInit ){
 825       wsdAutoext.nExt--;
 826       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
 827       n++;
 828       break;
 829     }
 830   }
 831   sqlite3_mutex_leave(mutex);
 832   return n;
 833 }
 834
 835 /*
 836 ** Reset the automatic extension loading mechanism.
 837 */
 838 void sqlite3_reset_auto_extension(void){
 839 #ifndef SQLITE_OMIT_AUTOINIT
 840   if( sqlite3_initialize()==SQLITE_OK )
 841 #endif
 842   {
 843 #if SQLITE_THREADSAFE
 844     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
 845 #endif
 846     wsdAutoextInit;
 847     sqlite3_mutex_enter(mutex);
 848     sqlite3_free(wsdAutoext.aExt);
 849     wsdAutoext.aExt = 0;
 850     wsdAutoext.nExt = 0;
 851     sqlite3_mutex_leave(mutex);
 852   }
 853 }
 854
 855 /*
 856 ** Load all automatic extensions.
 857 **
 858 ** If anything goes wrong, set an error in the database connection.
 859 */
 860 void sqlite3AutoLoadExtensions(sqlite3 *db){
 861   u32 i;
 862   int go = 1;
 863   int rc;
 864   sqlite3_loadext_entry xInit;
 865
 866   wsdAutoextInit;
 867   if( wsdAutoext.nExt==0 ){
 868     /* Common case: early out without every having to acquire a mutex */
 869     return;
 870   }
 871   for(i=0; go; i++){
 872     char *zErrmsg;
 873 #if SQLITE_THREADSAFE
 874     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN);
 875 #endif
 876 #ifdef SQLITE_OMIT_LOAD_EXTENSION
 877     const sqlite3_api_routines *pThunk = 0;
 878 #else
 879     const sqlite3_api_routines *pThunk = &sqlite3Apis;
 880 #endif
 881     sqlite3_mutex_enter(mutex);
 882     if( i>=wsdAutoext.nExt ){
 883       xInit = 0;
 884       go = 0;
 885     }else{
 886       xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
 887     }
 888     sqlite3_mutex_leave(mutex);
 889     zErrmsg = 0;
 890     if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
 891       sqlite3ErrorWithMsg(db, rc,
 892             "automatic extension loading failed: %s", zErrmsg);
 893       go = 0;
 894     }
 895     sqlite3_free(zErrmsg);
 896   }
 897 }