xref: /sqlite-3.40.0/src/loadext.c (revision 45f31be8) 
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 #endif
38 
39 #ifdef SQLITE_OMIT_AUTHORIZATION
40 # define sqlite3_set_authorizer         0
41 #endif
42 
43 #ifdef SQLITE_OMIT_UTF16
44 # define sqlite3_bind_text16            0
45 # define sqlite3_collation_needed16     0
46 # define sqlite3_column_decltype16      0
47 # define sqlite3_column_name16          0
48 # define sqlite3_column_text16          0
49 # define sqlite3_complete16             0
50 # define sqlite3_create_collation16     0
51 # define sqlite3_create_function16      0
52 # define sqlite3_errmsg16               0
53 # define sqlite3_open16                 0
54 # define sqlite3_prepare16              0
55 # define sqlite3_prepare16_v2           0
56 # define sqlite3_result_error16         0
57 # define sqlite3_result_text16          0
58 # define sqlite3_result_text16be        0
59 # define sqlite3_result_text16le        0
60 # define sqlite3_value_text16           0
61 # define sqlite3_value_text16be         0
62 # define sqlite3_value_text16le         0
63 # define sqlite3_column_database_name16 0
64 # define sqlite3_column_table_name16    0
65 # define sqlite3_column_origin_name16   0
66 #endif
67 
68 #ifdef SQLITE_OMIT_COMPLETE
69 # define sqlite3_complete 0
70 # define sqlite3_complete16 0
71 #endif
72 
73 #ifdef SQLITE_OMIT_DECLTYPE
74 # define sqlite3_column_decltype16      0
75 # define sqlite3_column_decltype        0
76 #endif
77 
78 #ifdef SQLITE_OMIT_PROGRESS_CALLBACK
79 # define sqlite3_progress_handler 0
80 #endif
81 
82 #ifdef SQLITE_OMIT_VIRTUALTABLE
83 # define sqlite3_create_module 0
84 # define sqlite3_create_module_v2 0
85 # define sqlite3_declare_vtab 0
86 # define sqlite3_vtab_config 0
87 # define sqlite3_vtab_on_conflict 0
88 #endif
89 
90 #ifdef SQLITE_OMIT_SHARED_CACHE
91 # define sqlite3_enable_shared_cache 0
92 #endif
93 
94 #ifdef SQLITE_OMIT_TRACE
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 /*
115 ** The following structure contains pointers to all SQLite API routines.
116 ** A pointer to this structure is passed into extensions when they are
117 ** loaded so that the extension can make calls back into the SQLite
118 ** library.
119 **
120 ** When adding new APIs, add them to the bottom of this structure
121 ** in order to preserve backwards compatibility.
122 **
123 ** Extensions that use newer APIs should first call the
124 ** sqlite3_libversion_number() to make sure that the API they
125 ** intend to use is supported by the library.  Extensions should
126 ** also check to make sure that the pointer to the function is
127 ** not NULL before calling it.
128 */
129 static const sqlite3_api_routines sqlite3Apis = {
130   sqlite3_aggregate_context,
131 #ifndef SQLITE_OMIT_DEPRECATED
132   sqlite3_aggregate_count,
133 #else
134   0,
135 #endif
136   sqlite3_bind_blob,
137   sqlite3_bind_double,
138   sqlite3_bind_int,
139   sqlite3_bind_int64,
140   sqlite3_bind_null,
141   sqlite3_bind_parameter_count,
142   sqlite3_bind_parameter_index,
143   sqlite3_bind_parameter_name,
144   sqlite3_bind_text,
145   sqlite3_bind_text16,
146   sqlite3_bind_value,
147   sqlite3_busy_handler,
148   sqlite3_busy_timeout,
149   sqlite3_changes,
150   sqlite3_close,
151   sqlite3_collation_needed,
152   sqlite3_collation_needed16,
153   sqlite3_column_blob,
154   sqlite3_column_bytes,
155   sqlite3_column_bytes16,
156   sqlite3_column_count,
157   sqlite3_column_database_name,
158   sqlite3_column_database_name16,
159   sqlite3_column_decltype,
160   sqlite3_column_decltype16,
161   sqlite3_column_double,
162   sqlite3_column_int,
163   sqlite3_column_int64,
164   sqlite3_column_name,
165   sqlite3_column_name16,
166   sqlite3_column_origin_name,
167   sqlite3_column_origin_name16,
168   sqlite3_column_table_name,
169   sqlite3_column_table_name16,
170   sqlite3_column_text,
171   sqlite3_column_text16,
172   sqlite3_column_type,
173   sqlite3_column_value,
174   sqlite3_commit_hook,
175   sqlite3_complete,
176   sqlite3_complete16,
177   sqlite3_create_collation,
178   sqlite3_create_collation16,
179   sqlite3_create_function,
180   sqlite3_create_function16,
181   sqlite3_create_module,
182   sqlite3_data_count,
183   sqlite3_db_handle,
184   sqlite3_declare_vtab,
185   sqlite3_enable_shared_cache,
186   sqlite3_errcode,
187   sqlite3_errmsg,
188   sqlite3_errmsg16,
189   sqlite3_exec,
190 #ifndef SQLITE_OMIT_DEPRECATED
191   sqlite3_expired,
192 #else
193   0,
194 #endif
195   sqlite3_finalize,
196   sqlite3_free,
197   sqlite3_free_table,
198   sqlite3_get_autocommit,
199   sqlite3_get_auxdata,
200   sqlite3_get_table,
201   0,     /* Was sqlite3_global_recover(), but that function is deprecated */
202   sqlite3_interrupt,
203   sqlite3_last_insert_rowid,
204   sqlite3_libversion,
205   sqlite3_libversion_number,
206   sqlite3_malloc,
207   sqlite3_mprintf,
208   sqlite3_open,
209   sqlite3_open16,
210   sqlite3_prepare,
211   sqlite3_prepare16,
212   sqlite3_profile,
213   sqlite3_progress_handler,
214   sqlite3_realloc,
215   sqlite3_reset,
216   sqlite3_result_blob,
217   sqlite3_result_double,
218   sqlite3_result_error,
219   sqlite3_result_error16,
220   sqlite3_result_int,
221   sqlite3_result_int64,
222   sqlite3_result_null,
223   sqlite3_result_text,
224   sqlite3_result_text16,
225   sqlite3_result_text16be,
226   sqlite3_result_text16le,
227   sqlite3_result_value,
228   sqlite3_rollback_hook,
229   sqlite3_set_authorizer,
230   sqlite3_set_auxdata,
231   sqlite3_snprintf,
232   sqlite3_step,
233   sqlite3_table_column_metadata,
234 #ifndef SQLITE_OMIT_DEPRECATED
235   sqlite3_thread_cleanup,
236 #else
237   0,
238 #endif
239   sqlite3_total_changes,
240   sqlite3_trace,
241 #ifndef SQLITE_OMIT_DEPRECATED
242   sqlite3_transfer_bindings,
243 #else
244   0,
245 #endif
246   sqlite3_update_hook,
247   sqlite3_user_data,
248   sqlite3_value_blob,
249   sqlite3_value_bytes,
250   sqlite3_value_bytes16,
251   sqlite3_value_double,
252   sqlite3_value_int,
253   sqlite3_value_int64,
254   sqlite3_value_numeric_type,
255   sqlite3_value_text,
256   sqlite3_value_text16,
257   sqlite3_value_text16be,
258   sqlite3_value_text16le,
259   sqlite3_value_type,
260   sqlite3_vmprintf,
261   /*
262   ** The original API set ends here.  All extensions can call any
263   ** of the APIs above provided that the pointer is not NULL.  But
264   ** before calling APIs that follow, extension should check the
265   ** sqlite3_libversion_number() to make sure they are dealing with
266   ** a library that is new enough to support that API.
267   *************************************************************************
268   */
269   sqlite3_overload_function,
270 
271   /*
272   ** Added after 3.3.13
273   */
274   sqlite3_prepare_v2,
275   sqlite3_prepare16_v2,
276   sqlite3_clear_bindings,
277 
278   /*
279   ** Added for 3.4.1
280   */
281   sqlite3_create_module_v2,
282 
283   /*
284   ** Added for 3.5.0
285   */
286   sqlite3_bind_zeroblob,
287   sqlite3_blob_bytes,
288   sqlite3_blob_close,
289   sqlite3_blob_open,
290   sqlite3_blob_read,
291   sqlite3_blob_write,
292   sqlite3_create_collation_v2,
293   sqlite3_file_control,
294   sqlite3_memory_highwater,
295   sqlite3_memory_used,
296 #ifdef SQLITE_MUTEX_OMIT
297   0,
298   0,
299   0,
300   0,
301   0,
302 #else
303   sqlite3_mutex_alloc,
304   sqlite3_mutex_enter,
305   sqlite3_mutex_free,
306   sqlite3_mutex_leave,
307   sqlite3_mutex_try,
308 #endif
309   sqlite3_open_v2,
310   sqlite3_release_memory,
311   sqlite3_result_error_nomem,
312   sqlite3_result_error_toobig,
313   sqlite3_sleep,
314   sqlite3_soft_heap_limit,
315   sqlite3_vfs_find,
316   sqlite3_vfs_register,
317   sqlite3_vfs_unregister,
318 
319   /*
320   ** Added for 3.5.8
321   */
322   sqlite3_threadsafe,
323   sqlite3_result_zeroblob,
324   sqlite3_result_error_code,
325   sqlite3_test_control,
326   sqlite3_randomness,
327   sqlite3_context_db_handle,
328 
329   /*
330   ** Added for 3.6.0
331   */
332   sqlite3_extended_result_codes,
333   sqlite3_limit,
334   sqlite3_next_stmt,
335   sqlite3_sql,
336   sqlite3_status,
337 
338   /*
339   ** Added for 3.7.4
340   */
341   sqlite3_backup_finish,
342   sqlite3_backup_init,
343   sqlite3_backup_pagecount,
344   sqlite3_backup_remaining,
345   sqlite3_backup_step,
346 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
347   sqlite3_compileoption_get,
348   sqlite3_compileoption_used,
349 #else
350   0,
351   0,
352 #endif
353   sqlite3_create_function_v2,
354   sqlite3_db_config,
355   sqlite3_db_mutex,
356   sqlite3_db_status,
357   sqlite3_extended_errcode,
358   sqlite3_log,
359   sqlite3_soft_heap_limit64,
360   sqlite3_sourceid,
361   sqlite3_stmt_status,
362   sqlite3_strnicmp,
363 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
364   sqlite3_unlock_notify,
365 #else
366   0,
367 #endif
368 #ifndef SQLITE_OMIT_WAL
369   sqlite3_wal_autocheckpoint,
370   sqlite3_wal_checkpoint,
371   sqlite3_wal_hook,
372 #else
373   0,
374   0,
375   0,
376 #endif
377   sqlite3_blob_reopen,
378   sqlite3_vtab_config,
379   sqlite3_vtab_on_conflict,
380   sqlite3_close_v2,
381   sqlite3_db_filename,
382   sqlite3_db_readonly,
383   sqlite3_db_release_memory,
384   sqlite3_errstr,
385   sqlite3_stmt_busy,
386   sqlite3_stmt_readonly,
387   sqlite3_stricmp,
388   sqlite3_uri_boolean,
389   sqlite3_uri_int64,
390   sqlite3_uri_parameter,
391   sqlite3_vsnprintf,
392   sqlite3_wal_checkpoint_v2,
393   /* Version 3.8.7 and later */
394   sqlite3_auto_extension,
395   sqlite3_bind_blob64,
396   sqlite3_bind_text64,
397   sqlite3_cancel_auto_extension,
398   sqlite3_load_extension,
399   sqlite3_malloc64,
400   sqlite3_msize,
401   sqlite3_realloc64,
402   sqlite3_reset_auto_extension,
403   sqlite3_result_blob64,
404   sqlite3_result_text64,
405   sqlite3_strglob,
406   /* Version 3.8.11 and later */
407   (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
408   sqlite3_value_free,
409   sqlite3_result_zeroblob64,
410   sqlite3_bind_zeroblob64,
411   /* Version 3.9.0 and later */
412   sqlite3_value_subtype,
413   sqlite3_result_subtype,
414   /* Version 3.10.0 and later */
415   sqlite3_status64,
416   sqlite3_strlike,
417   sqlite3_db_cacheflush
418 };
419 
420 /*
421 ** Attempt to load an SQLite extension library contained in the file
422 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
423 ** default entry point name (sqlite3_extension_init) is used.  Use
424 ** of the default name is recommended.
425 **
426 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
427 **
428 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
429 ** error message text.  The calling function should free this memory
430 ** by calling sqlite3DbFree(db, ).
431 */
432 static int sqlite3LoadExtension(
433   sqlite3 *db,          /* Load the extension into this database connection */
434   const char *zFile,    /* Name of the shared library containing extension */
435   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
436   char **pzErrMsg       /* Put error message here if not 0 */
437 ){
438   sqlite3_vfs *pVfs = db->pVfs;
439   void *handle;
440   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
441   char *zErrmsg = 0;
442   const char *zEntry;
443   char *zAltEntry = 0;
444   void **aHandle;
445   u64 nMsg = 300 + sqlite3Strlen30(zFile);
446   int ii;
447 
448   /* Shared library endings to try if zFile cannot be loaded as written */
449   static const char *azEndings[] = {
450 #if SQLITE_OS_WIN
451      "dll"
452 #elif defined(__APPLE__)
453      "dylib"
454 #else
455      "so"
456 #endif
457   };
458 
459 
460   if( pzErrMsg ) *pzErrMsg = 0;
461 
462   /* Ticket #1863.  To avoid a creating security problems for older
463   ** applications that relink against newer versions of SQLite, the
464   ** ability to run load_extension is turned off by default.  One
465   ** must call sqlite3_enable_load_extension() to turn on extension
466   ** loading.  Otherwise you get the following error.
467   */
468   if( (db->flags & SQLITE_LoadExtension)==0 ){
469     if( pzErrMsg ){
470       *pzErrMsg = sqlite3_mprintf("not authorized");
471     }
472     return SQLITE_ERROR;
473   }
474 
475   zEntry = zProc ? zProc : "sqlite3_extension_init";
476 
477   handle = sqlite3OsDlOpen(pVfs, zFile);
478 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
479   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
480     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
481     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
482     handle = sqlite3OsDlOpen(pVfs, zAltFile);
483     sqlite3_free(zAltFile);
484   }
485 #endif
486   if( handle==0 ){
487     if( pzErrMsg ){
488       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
489       if( zErrmsg ){
490         sqlite3_snprintf(nMsg, zErrmsg,
491             "unable to open shared library [%s]", zFile);
492         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
493       }
494     }
495     return SQLITE_ERROR;
496   }
497   xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
498                    sqlite3OsDlSym(pVfs, handle, zEntry);
499 
500   /* If no entry point was specified and the default legacy
501   ** entry point name "sqlite3_extension_init" was not found, then
502   ** construct an entry point name "sqlite3_X_init" where the X is
503   ** replaced by the lowercase value of every ASCII alphabetic
504   ** character in the filename after the last "/" upto the first ".",
505   ** and eliding the first three characters if they are "lib".
506   ** Examples:
507   **
508   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
509   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
510   */
511   if( xInit==0 && zProc==0 ){
512     int iFile, iEntry, c;
513     int ncFile = sqlite3Strlen30(zFile);
514     zAltEntry = sqlite3_malloc64(ncFile+30);
515     if( zAltEntry==0 ){
516       sqlite3OsDlClose(pVfs, handle);
517       return SQLITE_NOMEM_BKPT;
518     }
519     memcpy(zAltEntry, "sqlite3_", 8);
520     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
521     iFile++;
522     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
523     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
524       if( sqlite3Isalpha(c) ){
525         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
526       }
527     }
528     memcpy(zAltEntry+iEntry, "_init", 6);
529     zEntry = zAltEntry;
530     xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
531                      sqlite3OsDlSym(pVfs, handle, zEntry);
532   }
533   if( xInit==0 ){
534     if( pzErrMsg ){
535       nMsg += sqlite3Strlen30(zEntry);
536       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
537       if( zErrmsg ){
538         sqlite3_snprintf(nMsg, zErrmsg,
539             "no entry point [%s] in shared library [%s]", zEntry, zFile);
540         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
541       }
542     }
543     sqlite3OsDlClose(pVfs, handle);
544     sqlite3_free(zAltEntry);
545     return SQLITE_ERROR;
546   }
547   sqlite3_free(zAltEntry);
548   if( xInit(db, &zErrmsg, &sqlite3Apis) ){
549     if( pzErrMsg ){
550       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
551     }
552     sqlite3_free(zErrmsg);
553     sqlite3OsDlClose(pVfs, handle);
554     return SQLITE_ERROR;
555   }
556 
557   /* Append the new shared library handle to the db->aExtension array. */
558   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
559   if( aHandle==0 ){
560     return SQLITE_NOMEM_BKPT;
561   }
562   if( db->nExtension>0 ){
563     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
564   }
565   sqlite3DbFree(db, db->aExtension);
566   db->aExtension = aHandle;
567 
568   db->aExtension[db->nExtension++] = handle;
569   return SQLITE_OK;
570 }
571 int sqlite3_load_extension(
572   sqlite3 *db,          /* Load the extension into this database connection */
573   const char *zFile,    /* Name of the shared library containing extension */
574   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
575   char **pzErrMsg       /* Put error message here if not 0 */
576 ){
577   int rc;
578   sqlite3_mutex_enter(db->mutex);
579   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
580   rc = sqlite3ApiExit(db, rc);
581   sqlite3_mutex_leave(db->mutex);
582   return rc;
583 }
584 
585 /*
586 ** Call this routine when the database connection is closing in order
587 ** to clean up loaded extensions
588 */
589 void sqlite3CloseExtensions(sqlite3 *db){
590   int i;
591   assert( sqlite3_mutex_held(db->mutex) );
592   for(i=0; i<db->nExtension; i++){
593     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
594   }
595   sqlite3DbFree(db, db->aExtension);
596 }
597 
598 /*
599 ** Enable or disable extension loading.  Extension loading is disabled by
600 ** default so as not to open security holes in older applications.
601 */
602 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
603   sqlite3_mutex_enter(db->mutex);
604   if( onoff ){
605     db->flags |= SQLITE_LoadExtension;
606   }else{
607     db->flags &= ~SQLITE_LoadExtension;
608   }
609   sqlite3_mutex_leave(db->mutex);
610   return SQLITE_OK;
611 }
612 
613 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
614 
615 /*
616 ** The auto-extension code added regardless of whether or not extension
617 ** loading is supported.  We need a dummy sqlite3Apis pointer for that
618 ** code if regular extension loading is not available.  This is that
619 ** dummy pointer.
620 */
621 #ifdef SQLITE_OMIT_LOAD_EXTENSION
622 static const sqlite3_api_routines sqlite3Apis = { 0 };
623 #endif
624 
625 
626 /*
627 ** The following object holds the list of automatically loaded
628 ** extensions.
629 **
630 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
631 ** mutex must be held while accessing this list.
632 */
633 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
634 static SQLITE_WSD struct sqlite3AutoExtList {
635   u32 nExt;              /* Number of entries in aExt[] */
636   void (**aExt)(void);   /* Pointers to the extension init functions */
637 } sqlite3Autoext = { 0, 0 };
638 
639 /* The "wsdAutoext" macro will resolve to the autoextension
640 ** state vector.  If writable static data is unsupported on the target,
641 ** we have to locate the state vector at run-time.  In the more common
642 ** case where writable static data is supported, wsdStat can refer directly
643 ** to the "sqlite3Autoext" state vector declared above.
644 */
645 #ifdef SQLITE_OMIT_WSD
646 # define wsdAutoextInit \
647   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
648 # define wsdAutoext x[0]
649 #else
650 # define wsdAutoextInit
651 # define wsdAutoext sqlite3Autoext
652 #endif
653 
654 
655 /*
656 ** Register a statically linked extension that is automatically
657 ** loaded by every new database connection.
658 */
659 int sqlite3_auto_extension(void (*xInit)(void)){
660   int rc = SQLITE_OK;
661 #ifndef SQLITE_OMIT_AUTOINIT
662   rc = sqlite3_initialize();
663   if( rc ){
664     return rc;
665   }else
666 #endif
667   {
668     u32 i;
669 #if SQLITE_THREADSAFE
670     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
671 #endif
672     wsdAutoextInit;
673     sqlite3_mutex_enter(mutex);
674     for(i=0; i<wsdAutoext.nExt; i++){
675       if( wsdAutoext.aExt[i]==xInit ) break;
676     }
677     if( i==wsdAutoext.nExt ){
678       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
679       void (**aNew)(void);
680       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
681       if( aNew==0 ){
682         rc = SQLITE_NOMEM_BKPT;
683       }else{
684         wsdAutoext.aExt = aNew;
685         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
686         wsdAutoext.nExt++;
687       }
688     }
689     sqlite3_mutex_leave(mutex);
690     assert( (rc&0xff)==rc );
691     return rc;
692   }
693 }
694 
695 /*
696 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
697 ** set of routines that is invoked for each new database connection, if it
698 ** is currently on the list.  If xInit is not on the list, then this
699 ** routine is a no-op.
700 **
701 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
702 ** was not on the list.
703 */
704 int sqlite3_cancel_auto_extension(void (*xInit)(void)){
705 #if SQLITE_THREADSAFE
706   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
707 #endif
708   int i;
709   int n = 0;
710   wsdAutoextInit;
711   sqlite3_mutex_enter(mutex);
712   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
713     if( wsdAutoext.aExt[i]==xInit ){
714       wsdAutoext.nExt--;
715       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
716       n++;
717       break;
718     }
719   }
720   sqlite3_mutex_leave(mutex);
721   return n;
722 }
723 
724 /*
725 ** Reset the automatic extension loading mechanism.
726 */
727 void sqlite3_reset_auto_extension(void){
728 #ifndef SQLITE_OMIT_AUTOINIT
729   if( sqlite3_initialize()==SQLITE_OK )
730 #endif
731   {
732 #if SQLITE_THREADSAFE
733     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
734 #endif
735     wsdAutoextInit;
736     sqlite3_mutex_enter(mutex);
737     sqlite3_free(wsdAutoext.aExt);
738     wsdAutoext.aExt = 0;
739     wsdAutoext.nExt = 0;
740     sqlite3_mutex_leave(mutex);
741   }
742 }
743 
744 /*
745 ** Load all automatic extensions.
746 **
747 ** If anything goes wrong, set an error in the database connection.
748 */
749 void sqlite3AutoLoadExtensions(sqlite3 *db){
750   u32 i;
751   int go = 1;
752   int rc;
753   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
754 
755   wsdAutoextInit;
756   if( wsdAutoext.nExt==0 ){
757     /* Common case: early out without every having to acquire a mutex */
758     return;
759   }
760   for(i=0; go; i++){
761     char *zErrmsg;
762 #if SQLITE_THREADSAFE
763     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
764 #endif
765     sqlite3_mutex_enter(mutex);
766     if( i>=wsdAutoext.nExt ){
767       xInit = 0;
768       go = 0;
769     }else{
770       xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
771               wsdAutoext.aExt[i];
772     }
773     sqlite3_mutex_leave(mutex);
774     zErrmsg = 0;
775     if( xInit && (rc = xInit(db, &zErrmsg, &sqlite3Apis))!=0 ){
776       sqlite3ErrorWithMsg(db, rc,
777             "automatic extension loading failed: %s", zErrmsg);
778       go = 0;
779     }
780     sqlite3_free(zErrmsg);
781   }
782 }
783