xref: /sqlite-3.40.0/src/loadext.c (revision 47ebd4ca) 
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 };
432 
433 /*
434 ** Attempt to load an SQLite extension library contained in the file
435 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
436 ** default entry point name (sqlite3_extension_init) is used.  Use
437 ** of the default name is recommended.
438 **
439 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
440 **
441 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
442 ** error message text.  The calling function should free this memory
443 ** by calling sqlite3DbFree(db, ).
444 */
445 static int sqlite3LoadExtension(
446   sqlite3 *db,          /* Load the extension into this database connection */
447   const char *zFile,    /* Name of the shared library containing extension */
448   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
449   char **pzErrMsg       /* Put error message here if not 0 */
450 ){
451   sqlite3_vfs *pVfs = db->pVfs;
452   void *handle;
453   sqlite3_loadext_entry xInit;
454   char *zErrmsg = 0;
455   const char *zEntry;
456   char *zAltEntry = 0;
457   void **aHandle;
458   u64 nMsg = 300 + sqlite3Strlen30(zFile);
459   int ii;
460   int rc;
461 
462   /* Shared library endings to try if zFile cannot be loaded as written */
463   static const char *azEndings[] = {
464 #if SQLITE_OS_WIN
465      "dll"
466 #elif defined(__APPLE__)
467      "dylib"
468 #else
469      "so"
470 #endif
471   };
472 
473 
474   if( pzErrMsg ) *pzErrMsg = 0;
475 
476   /* Ticket #1863.  To avoid a creating security problems for older
477   ** applications that relink against newer versions of SQLite, the
478   ** ability to run load_extension is turned off by default.  One
479   ** must call either sqlite3_enable_load_extension(db) or
480   ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
481   ** to turn on extension loading.
482   */
483   if( (db->flags & SQLITE_LoadExtension)==0 ){
484     if( pzErrMsg ){
485       *pzErrMsg = sqlite3_mprintf("not authorized");
486     }
487     return SQLITE_ERROR;
488   }
489 
490   zEntry = zProc ? zProc : "sqlite3_extension_init";
491 
492   handle = sqlite3OsDlOpen(pVfs, zFile);
493 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
494   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
495     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
496     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
497     handle = sqlite3OsDlOpen(pVfs, zAltFile);
498     sqlite3_free(zAltFile);
499   }
500 #endif
501   if( handle==0 ){
502     if( pzErrMsg ){
503       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
504       if( zErrmsg ){
505         sqlite3_snprintf(nMsg, zErrmsg,
506             "unable to open shared library [%s]", zFile);
507         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
508       }
509     }
510     return SQLITE_ERROR;
511   }
512   xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
513 
514   /* If no entry point was specified and the default legacy
515   ** entry point name "sqlite3_extension_init" was not found, then
516   ** construct an entry point name "sqlite3_X_init" where the X is
517   ** replaced by the lowercase value of every ASCII alphabetic
518   ** character in the filename after the last "/" upto the first ".",
519   ** and eliding the first three characters if they are "lib".
520   ** Examples:
521   **
522   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
523   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
524   */
525   if( xInit==0 && zProc==0 ){
526     int iFile, iEntry, c;
527     int ncFile = sqlite3Strlen30(zFile);
528     zAltEntry = sqlite3_malloc64(ncFile+30);
529     if( zAltEntry==0 ){
530       sqlite3OsDlClose(pVfs, handle);
531       return SQLITE_NOMEM_BKPT;
532     }
533     memcpy(zAltEntry, "sqlite3_", 8);
534     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
535     iFile++;
536     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
537     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
538       if( sqlite3Isalpha(c) ){
539         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
540       }
541     }
542     memcpy(zAltEntry+iEntry, "_init", 6);
543     zEntry = zAltEntry;
544     xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
545   }
546   if( xInit==0 ){
547     if( pzErrMsg ){
548       nMsg += sqlite3Strlen30(zEntry);
549       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
550       if( zErrmsg ){
551         sqlite3_snprintf(nMsg, zErrmsg,
552             "no entry point [%s] in shared library [%s]", zEntry, zFile);
553         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
554       }
555     }
556     sqlite3OsDlClose(pVfs, handle);
557     sqlite3_free(zAltEntry);
558     return SQLITE_ERROR;
559   }
560   sqlite3_free(zAltEntry);
561   rc = xInit(db, &zErrmsg, &sqlite3Apis);
562   if( rc ){
563     if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
564     if( pzErrMsg ){
565       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
566     }
567     sqlite3_free(zErrmsg);
568     sqlite3OsDlClose(pVfs, handle);
569     return SQLITE_ERROR;
570   }
571 
572   /* Append the new shared library handle to the db->aExtension array. */
573   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
574   if( aHandle==0 ){
575     return SQLITE_NOMEM_BKPT;
576   }
577   if( db->nExtension>0 ){
578     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
579   }
580   sqlite3DbFree(db, db->aExtension);
581   db->aExtension = aHandle;
582 
583   db->aExtension[db->nExtension++] = handle;
584   return SQLITE_OK;
585 }
586 int sqlite3_load_extension(
587   sqlite3 *db,          /* Load the extension into this database connection */
588   const char *zFile,    /* Name of the shared library containing extension */
589   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
590   char **pzErrMsg       /* Put error message here if not 0 */
591 ){
592   int rc;
593   sqlite3_mutex_enter(db->mutex);
594   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
595   rc = sqlite3ApiExit(db, rc);
596   sqlite3_mutex_leave(db->mutex);
597   return rc;
598 }
599 
600 /*
601 ** Call this routine when the database connection is closing in order
602 ** to clean up loaded extensions
603 */
604 void sqlite3CloseExtensions(sqlite3 *db){
605   int i;
606   assert( sqlite3_mutex_held(db->mutex) );
607   for(i=0; i<db->nExtension; i++){
608     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
609   }
610   sqlite3DbFree(db, db->aExtension);
611 }
612 
613 /*
614 ** Enable or disable extension loading.  Extension loading is disabled by
615 ** default so as not to open security holes in older applications.
616 */
617 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
618   sqlite3_mutex_enter(db->mutex);
619   if( onoff ){
620     db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
621   }else{
622     db->flags &= ~(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
623   }
624   sqlite3_mutex_leave(db->mutex);
625   return SQLITE_OK;
626 }
627 
628 #endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
629 
630 /*
631 ** The following object holds the list of automatically loaded
632 ** extensions.
633 **
634 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
635 ** mutex must be held while accessing this list.
636 */
637 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
638 static SQLITE_WSD struct sqlite3AutoExtList {
639   u32 nExt;              /* Number of entries in aExt[] */
640   void (**aExt)(void);   /* Pointers to the extension init functions */
641 } sqlite3Autoext = { 0, 0 };
642 
643 /* The "wsdAutoext" macro will resolve to the autoextension
644 ** state vector.  If writable static data is unsupported on the target,
645 ** we have to locate the state vector at run-time.  In the more common
646 ** case where writable static data is supported, wsdStat can refer directly
647 ** to the "sqlite3Autoext" state vector declared above.
648 */
649 #ifdef SQLITE_OMIT_WSD
650 # define wsdAutoextInit \
651   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
652 # define wsdAutoext x[0]
653 #else
654 # define wsdAutoextInit
655 # define wsdAutoext sqlite3Autoext
656 #endif
657 
658 
659 /*
660 ** Register a statically linked extension that is automatically
661 ** loaded by every new database connection.
662 */
663 int sqlite3_auto_extension(
664   void (*xInit)(void)
665 ){
666   int rc = SQLITE_OK;
667 #ifndef SQLITE_OMIT_AUTOINIT
668   rc = sqlite3_initialize();
669   if( rc ){
670     return rc;
671   }else
672 #endif
673   {
674     u32 i;
675 #if SQLITE_THREADSAFE
676     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
677 #endif
678     wsdAutoextInit;
679     sqlite3_mutex_enter(mutex);
680     for(i=0; i<wsdAutoext.nExt; i++){
681       if( wsdAutoext.aExt[i]==xInit ) break;
682     }
683     if( i==wsdAutoext.nExt ){
684       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
685       void (**aNew)(void);
686       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
687       if( aNew==0 ){
688         rc = SQLITE_NOMEM_BKPT;
689       }else{
690         wsdAutoext.aExt = aNew;
691         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
692         wsdAutoext.nExt++;
693       }
694     }
695     sqlite3_mutex_leave(mutex);
696     assert( (rc&0xff)==rc );
697     return rc;
698   }
699 }
700 
701 /*
702 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
703 ** set of routines that is invoked for each new database connection, if it
704 ** is currently on the list.  If xInit is not on the list, then this
705 ** routine is a no-op.
706 **
707 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
708 ** was not on the list.
709 */
710 int sqlite3_cancel_auto_extension(
711   void (*xInit)(void)
712 ){
713 #if SQLITE_THREADSAFE
714   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
715 #endif
716   int i;
717   int n = 0;
718   wsdAutoextInit;
719   sqlite3_mutex_enter(mutex);
720   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
721     if( wsdAutoext.aExt[i]==xInit ){
722       wsdAutoext.nExt--;
723       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
724       n++;
725       break;
726     }
727   }
728   sqlite3_mutex_leave(mutex);
729   return n;
730 }
731 
732 /*
733 ** Reset the automatic extension loading mechanism.
734 */
735 void sqlite3_reset_auto_extension(void){
736 #ifndef SQLITE_OMIT_AUTOINIT
737   if( sqlite3_initialize()==SQLITE_OK )
738 #endif
739   {
740 #if SQLITE_THREADSAFE
741     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
742 #endif
743     wsdAutoextInit;
744     sqlite3_mutex_enter(mutex);
745     sqlite3_free(wsdAutoext.aExt);
746     wsdAutoext.aExt = 0;
747     wsdAutoext.nExt = 0;
748     sqlite3_mutex_leave(mutex);
749   }
750 }
751 
752 /*
753 ** Load all automatic extensions.
754 **
755 ** If anything goes wrong, set an error in the database connection.
756 */
757 void sqlite3AutoLoadExtensions(sqlite3 *db){
758   u32 i;
759   int go = 1;
760   int rc;
761   sqlite3_loadext_entry xInit;
762 
763   wsdAutoextInit;
764   if( wsdAutoext.nExt==0 ){
765     /* Common case: early out without every having to acquire a mutex */
766     return;
767   }
768   for(i=0; go; i++){
769     char *zErrmsg;
770 #if SQLITE_THREADSAFE
771     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
772 #endif
773 #ifdef SQLITE_OMIT_LOAD_EXTENSION
774     const sqlite3_api_routines *pThunk = 0;
775 #else
776     const sqlite3_api_routines *pThunk = &sqlite3Apis;
777 #endif
778     sqlite3_mutex_enter(mutex);
779     if( i>=wsdAutoext.nExt ){
780       xInit = 0;
781       go = 0;
782     }else{
783       xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
784     }
785     sqlite3_mutex_leave(mutex);
786     zErrmsg = 0;
787     if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
788       sqlite3ErrorWithMsg(db, rc,
789             "automatic extension loading failed: %s", zErrmsg);
790       go = 0;
791     }
792     sqlite3_free(zErrmsg);
793   }
794 }
795