xref: /sqlite-3.40.0/src/loadext.c (revision e99cb2da)
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 };
474 
475 /*
476 ** Attempt to load an SQLite extension library contained in the file
477 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
478 ** default entry point name (sqlite3_extension_init) is used.  Use
479 ** of the default name is recommended.
480 **
481 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
482 **
483 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
484 ** error message text.  The calling function should free this memory
485 ** by calling sqlite3DbFree(db, ).
486 */
487 static int sqlite3LoadExtension(
488   sqlite3 *db,          /* Load the extension into this database connection */
489   const char *zFile,    /* Name of the shared library containing extension */
490   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
491   char **pzErrMsg       /* Put error message here if not 0 */
492 ){
493   sqlite3_vfs *pVfs = db->pVfs;
494   void *handle;
495   sqlite3_loadext_entry xInit;
496   char *zErrmsg = 0;
497   const char *zEntry;
498   char *zAltEntry = 0;
499   void **aHandle;
500   u64 nMsg = 300 + sqlite3Strlen30(zFile);
501   int ii;
502   int rc;
503 
504   /* Shared library endings to try if zFile cannot be loaded as written */
505   static const char *azEndings[] = {
506 #if SQLITE_OS_WIN
507      "dll"
508 #elif defined(__APPLE__)
509      "dylib"
510 #else
511      "so"
512 #endif
513   };
514 
515 
516   if( pzErrMsg ) *pzErrMsg = 0;
517 
518   /* Ticket #1863.  To avoid a creating security problems for older
519   ** applications that relink against newer versions of SQLite, the
520   ** ability to run load_extension is turned off by default.  One
521   ** must call either sqlite3_enable_load_extension(db) or
522   ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
523   ** to turn on extension loading.
524   */
525   if( (db->flags & SQLITE_LoadExtension)==0 ){
526     if( pzErrMsg ){
527       *pzErrMsg = sqlite3_mprintf("not authorized");
528     }
529     return SQLITE_ERROR;
530   }
531 
532   zEntry = zProc ? zProc : "sqlite3_extension_init";
533 
534   handle = sqlite3OsDlOpen(pVfs, zFile);
535 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
536   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
537     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
538     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
539     handle = sqlite3OsDlOpen(pVfs, zAltFile);
540     sqlite3_free(zAltFile);
541   }
542 #endif
543   if( handle==0 ){
544     if( pzErrMsg ){
545       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
546       if( zErrmsg ){
547         sqlite3_snprintf(nMsg, zErrmsg,
548             "unable to open shared library [%s]", zFile);
549         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
550       }
551     }
552     return SQLITE_ERROR;
553   }
554   xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
555 
556   /* If no entry point was specified and the default legacy
557   ** entry point name "sqlite3_extension_init" was not found, then
558   ** construct an entry point name "sqlite3_X_init" where the X is
559   ** replaced by the lowercase value of every ASCII alphabetic
560   ** character in the filename after the last "/" upto the first ".",
561   ** and eliding the first three characters if they are "lib".
562   ** Examples:
563   **
564   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
565   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
566   */
567   if( xInit==0 && zProc==0 ){
568     int iFile, iEntry, c;
569     int ncFile = sqlite3Strlen30(zFile);
570     zAltEntry = sqlite3_malloc64(ncFile+30);
571     if( zAltEntry==0 ){
572       sqlite3OsDlClose(pVfs, handle);
573       return SQLITE_NOMEM_BKPT;
574     }
575     memcpy(zAltEntry, "sqlite3_", 8);
576     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
577     iFile++;
578     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
579     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
580       if( sqlite3Isalpha(c) ){
581         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
582       }
583     }
584     memcpy(zAltEntry+iEntry, "_init", 6);
585     zEntry = zAltEntry;
586     xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
587   }
588   if( xInit==0 ){
589     if( pzErrMsg ){
590       nMsg += sqlite3Strlen30(zEntry);
591       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
592       if( zErrmsg ){
593         sqlite3_snprintf(nMsg, zErrmsg,
594             "no entry point [%s] in shared library [%s]", zEntry, zFile);
595         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
596       }
597     }
598     sqlite3OsDlClose(pVfs, handle);
599     sqlite3_free(zAltEntry);
600     return SQLITE_ERROR;
601   }
602   sqlite3_free(zAltEntry);
603   rc = xInit(db, &zErrmsg, &sqlite3Apis);
604   if( rc ){
605     if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
606     if( pzErrMsg ){
607       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
608     }
609     sqlite3_free(zErrmsg);
610     sqlite3OsDlClose(pVfs, handle);
611     return SQLITE_ERROR;
612   }
613 
614   /* Append the new shared library handle to the db->aExtension array. */
615   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
616   if( aHandle==0 ){
617     return SQLITE_NOMEM_BKPT;
618   }
619   if( db->nExtension>0 ){
620     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
621   }
622   sqlite3DbFree(db, db->aExtension);
623   db->aExtension = aHandle;
624 
625   db->aExtension[db->nExtension++] = handle;
626   return SQLITE_OK;
627 }
628 int sqlite3_load_extension(
629   sqlite3 *db,          /* Load the extension into this database connection */
630   const char *zFile,    /* Name of the shared library containing extension */
631   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
632   char **pzErrMsg       /* Put error message here if not 0 */
633 ){
634   int rc;
635   sqlite3_mutex_enter(db->mutex);
636   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
637   rc = sqlite3ApiExit(db, rc);
638   sqlite3_mutex_leave(db->mutex);
639   return rc;
640 }
641 
642 /*
643 ** Call this routine when the database connection is closing in order
644 ** to clean up loaded extensions
645 */
646 void sqlite3CloseExtensions(sqlite3 *db){
647   int i;
648   assert( sqlite3_mutex_held(db->mutex) );
649   for(i=0; i<db->nExtension; i++){
650     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
651   }
652   sqlite3DbFree(db, db->aExtension);
653 }
654 
655 /*
656 ** Enable or disable extension loading.  Extension loading is disabled by
657 ** default so as not to open security holes in older applications.
658 */
659 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
660   sqlite3_mutex_enter(db->mutex);
661   if( onoff ){
662     db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
663   }else{
664     db->flags &= ~(u64)(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
665   }
666   sqlite3_mutex_leave(db->mutex);
667   return SQLITE_OK;
668 }
669 
670 #endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
671 
672 /*
673 ** The following object holds the list of automatically loaded
674 ** extensions.
675 **
676 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
677 ** mutex must be held while accessing this list.
678 */
679 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
680 static SQLITE_WSD struct sqlite3AutoExtList {
681   u32 nExt;              /* Number of entries in aExt[] */
682   void (**aExt)(void);   /* Pointers to the extension init functions */
683 } sqlite3Autoext = { 0, 0 };
684 
685 /* The "wsdAutoext" macro will resolve to the autoextension
686 ** state vector.  If writable static data is unsupported on the target,
687 ** we have to locate the state vector at run-time.  In the more common
688 ** case where writable static data is supported, wsdStat can refer directly
689 ** to the "sqlite3Autoext" state vector declared above.
690 */
691 #ifdef SQLITE_OMIT_WSD
692 # define wsdAutoextInit \
693   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
694 # define wsdAutoext x[0]
695 #else
696 # define wsdAutoextInit
697 # define wsdAutoext sqlite3Autoext
698 #endif
699 
700 
701 /*
702 ** Register a statically linked extension that is automatically
703 ** loaded by every new database connection.
704 */
705 int sqlite3_auto_extension(
706   void (*xInit)(void)
707 ){
708   int rc = SQLITE_OK;
709 #ifndef SQLITE_OMIT_AUTOINIT
710   rc = sqlite3_initialize();
711   if( rc ){
712     return rc;
713   }else
714 #endif
715   {
716     u32 i;
717 #if SQLITE_THREADSAFE
718     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
719 #endif
720     wsdAutoextInit;
721     sqlite3_mutex_enter(mutex);
722     for(i=0; i<wsdAutoext.nExt; i++){
723       if( wsdAutoext.aExt[i]==xInit ) break;
724     }
725     if( i==wsdAutoext.nExt ){
726       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
727       void (**aNew)(void);
728       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
729       if( aNew==0 ){
730         rc = SQLITE_NOMEM_BKPT;
731       }else{
732         wsdAutoext.aExt = aNew;
733         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
734         wsdAutoext.nExt++;
735       }
736     }
737     sqlite3_mutex_leave(mutex);
738     assert( (rc&0xff)==rc );
739     return rc;
740   }
741 }
742 
743 /*
744 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
745 ** set of routines that is invoked for each new database connection, if it
746 ** is currently on the list.  If xInit is not on the list, then this
747 ** routine is a no-op.
748 **
749 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
750 ** was not on the list.
751 */
752 int sqlite3_cancel_auto_extension(
753   void (*xInit)(void)
754 ){
755 #if SQLITE_THREADSAFE
756   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
757 #endif
758   int i;
759   int n = 0;
760   wsdAutoextInit;
761   sqlite3_mutex_enter(mutex);
762   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
763     if( wsdAutoext.aExt[i]==xInit ){
764       wsdAutoext.nExt--;
765       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
766       n++;
767       break;
768     }
769   }
770   sqlite3_mutex_leave(mutex);
771   return n;
772 }
773 
774 /*
775 ** Reset the automatic extension loading mechanism.
776 */
777 void sqlite3_reset_auto_extension(void){
778 #ifndef SQLITE_OMIT_AUTOINIT
779   if( sqlite3_initialize()==SQLITE_OK )
780 #endif
781   {
782 #if SQLITE_THREADSAFE
783     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
784 #endif
785     wsdAutoextInit;
786     sqlite3_mutex_enter(mutex);
787     sqlite3_free(wsdAutoext.aExt);
788     wsdAutoext.aExt = 0;
789     wsdAutoext.nExt = 0;
790     sqlite3_mutex_leave(mutex);
791   }
792 }
793 
794 /*
795 ** Load all automatic extensions.
796 **
797 ** If anything goes wrong, set an error in the database connection.
798 */
799 void sqlite3AutoLoadExtensions(sqlite3 *db){
800   u32 i;
801   int go = 1;
802   int rc;
803   sqlite3_loadext_entry xInit;
804 
805   wsdAutoextInit;
806   if( wsdAutoext.nExt==0 ){
807     /* Common case: early out without every having to acquire a mutex */
808     return;
809   }
810   for(i=0; go; i++){
811     char *zErrmsg;
812 #if SQLITE_THREADSAFE
813     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
814 #endif
815 #ifdef SQLITE_OMIT_LOAD_EXTENSION
816     const sqlite3_api_routines *pThunk = 0;
817 #else
818     const sqlite3_api_routines *pThunk = &sqlite3Apis;
819 #endif
820     sqlite3_mutex_enter(mutex);
821     if( i>=wsdAutoext.nExt ){
822       xInit = 0;
823       go = 0;
824     }else{
825       xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
826     }
827     sqlite3_mutex_leave(mutex);
828     zErrmsg = 0;
829     if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
830       sqlite3ErrorWithMsg(db, rc,
831             "automatic extension loading failed: %s", zErrmsg);
832       go = 0;
833     }
834     sqlite3_free(zErrmsg);
835   }
836 }
837