xref: /sqlite-3.40.0/src/loadext.c (revision e7952263) 
1 /*
2 ** 2006 June 7
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This file contains code used to dynamically load extensions into
13 ** the SQLite library.
14 */
15 
16 #ifndef SQLITE_CORE
17   #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
18 #endif
19 #include "sqlite3ext.h"
20 #include "sqliteInt.h"
21 
22 #ifndef SQLITE_OMIT_LOAD_EXTENSION
23 /*
24 ** Some API routines are omitted when various features are
25 ** excluded from a build of SQLite.  Substitute a NULL pointer
26 ** for any missing APIs.
27 */
28 #ifndef SQLITE_ENABLE_COLUMN_METADATA
29 # define sqlite3_column_database_name   0
30 # define sqlite3_column_database_name16 0
31 # define sqlite3_column_table_name      0
32 # define sqlite3_column_table_name16    0
33 # define sqlite3_column_origin_name     0
34 # define sqlite3_column_origin_name16   0
35 #endif
36 
37 #ifdef SQLITE_OMIT_AUTHORIZATION
38 # define sqlite3_set_authorizer         0
39 #endif
40 
41 #ifdef SQLITE_OMIT_UTF16
42 # define sqlite3_bind_text16            0
43 # define sqlite3_collation_needed16     0
44 # define sqlite3_column_decltype16      0
45 # define sqlite3_column_name16          0
46 # define sqlite3_column_text16          0
47 # define sqlite3_complete16             0
48 # define sqlite3_create_collation16     0
49 # define sqlite3_create_function16      0
50 # define sqlite3_errmsg16               0
51 # define sqlite3_open16                 0
52 # define sqlite3_prepare16              0
53 # define sqlite3_prepare16_v2           0
54 # define sqlite3_prepare16_v3           0
55 # define sqlite3_result_error16         0
56 # define sqlite3_result_text16          0
57 # define sqlite3_result_text16be        0
58 # define sqlite3_result_text16le        0
59 # define sqlite3_value_text16           0
60 # define sqlite3_value_text16be         0
61 # define sqlite3_value_text16le         0
62 # define sqlite3_column_database_name16 0
63 # define sqlite3_column_table_name16    0
64 # define sqlite3_column_origin_name16   0
65 #endif
66 
67 #ifdef SQLITE_OMIT_COMPLETE
68 # define sqlite3_complete 0
69 # define sqlite3_complete16 0
70 #endif
71 
72 #ifdef SQLITE_OMIT_DECLTYPE
73 # define sqlite3_column_decltype16      0
74 # define sqlite3_column_decltype        0
75 #endif
76 
77 #ifdef SQLITE_OMIT_PROGRESS_CALLBACK
78 # define sqlite3_progress_handler 0
79 #endif
80 
81 #ifdef SQLITE_OMIT_VIRTUALTABLE
82 # define sqlite3_create_module 0
83 # define sqlite3_create_module_v2 0
84 # define sqlite3_declare_vtab 0
85 # define sqlite3_vtab_config 0
86 # define sqlite3_vtab_on_conflict 0
87 #endif
88 
89 #ifdef SQLITE_OMIT_SHARED_CACHE
90 # define sqlite3_enable_shared_cache 0
91 #endif
92 
93 #if defined(SQLITE_OMIT_TRACE) || defined(SQLITE_OMIT_DEPRECATED)
94 # define sqlite3_profile       0
95 # define sqlite3_trace         0
96 #endif
97 
98 #ifdef SQLITE_OMIT_GET_TABLE
99 # define sqlite3_free_table    0
100 # define sqlite3_get_table     0
101 #endif
102 
103 #ifdef SQLITE_OMIT_INCRBLOB
104 #define sqlite3_bind_zeroblob  0
105 #define sqlite3_blob_bytes     0
106 #define sqlite3_blob_close     0
107 #define sqlite3_blob_open      0
108 #define sqlite3_blob_read      0
109 #define sqlite3_blob_write     0
110 #define sqlite3_blob_reopen    0
111 #endif
112 
113 #if defined(SQLITE_OMIT_TRACE)
114 # define sqlite3_trace_v2      0
115 #endif
116 
117 /*
118 ** The following structure contains pointers to all SQLite API routines.
119 ** A pointer to this structure is passed into extensions when they are
120 ** loaded so that the extension can make calls back into the SQLite
121 ** library.
122 **
123 ** When adding new APIs, add them to the bottom of this structure
124 ** in order to preserve backwards compatibility.
125 **
126 ** Extensions that use newer APIs should first call the
127 ** sqlite3_libversion_number() to make sure that the API they
128 ** intend to use is supported by the library.  Extensions should
129 ** also check to make sure that the pointer to the function is
130 ** not NULL before calling it.
131 */
132 static const sqlite3_api_routines sqlite3Apis = {
133   sqlite3_aggregate_context,
134 #ifndef SQLITE_OMIT_DEPRECATED
135   sqlite3_aggregate_count,
136 #else
137   0,
138 #endif
139   sqlite3_bind_blob,
140   sqlite3_bind_double,
141   sqlite3_bind_int,
142   sqlite3_bind_int64,
143   sqlite3_bind_null,
144   sqlite3_bind_parameter_count,
145   sqlite3_bind_parameter_index,
146   sqlite3_bind_parameter_name,
147   sqlite3_bind_text,
148   sqlite3_bind_text16,
149   sqlite3_bind_value,
150   sqlite3_busy_handler,
151   sqlite3_busy_timeout,
152   sqlite3_changes,
153   sqlite3_close,
154   sqlite3_collation_needed,
155   sqlite3_collation_needed16,
156   sqlite3_column_blob,
157   sqlite3_column_bytes,
158   sqlite3_column_bytes16,
159   sqlite3_column_count,
160   sqlite3_column_database_name,
161   sqlite3_column_database_name16,
162   sqlite3_column_decltype,
163   sqlite3_column_decltype16,
164   sqlite3_column_double,
165   sqlite3_column_int,
166   sqlite3_column_int64,
167   sqlite3_column_name,
168   sqlite3_column_name16,
169   sqlite3_column_origin_name,
170   sqlite3_column_origin_name16,
171   sqlite3_column_table_name,
172   sqlite3_column_table_name16,
173   sqlite3_column_text,
174   sqlite3_column_text16,
175   sqlite3_column_type,
176   sqlite3_column_value,
177   sqlite3_commit_hook,
178   sqlite3_complete,
179   sqlite3_complete16,
180   sqlite3_create_collation,
181   sqlite3_create_collation16,
182   sqlite3_create_function,
183   sqlite3_create_function16,
184   sqlite3_create_module,
185   sqlite3_data_count,
186   sqlite3_db_handle,
187   sqlite3_declare_vtab,
188   sqlite3_enable_shared_cache,
189   sqlite3_errcode,
190   sqlite3_errmsg,
191   sqlite3_errmsg16,
192   sqlite3_exec,
193 #ifndef SQLITE_OMIT_DEPRECATED
194   sqlite3_expired,
195 #else
196   0,
197 #endif
198   sqlite3_finalize,
199   sqlite3_free,
200   sqlite3_free_table,
201   sqlite3_get_autocommit,
202   sqlite3_get_auxdata,
203   sqlite3_get_table,
204   0,     /* Was sqlite3_global_recover(), but that function is deprecated */
205   sqlite3_interrupt,
206   sqlite3_last_insert_rowid,
207   sqlite3_libversion,
208   sqlite3_libversion_number,
209   sqlite3_malloc,
210   sqlite3_mprintf,
211   sqlite3_open,
212   sqlite3_open16,
213   sqlite3_prepare,
214   sqlite3_prepare16,
215   sqlite3_profile,
216   sqlite3_progress_handler,
217   sqlite3_realloc,
218   sqlite3_reset,
219   sqlite3_result_blob,
220   sqlite3_result_double,
221   sqlite3_result_error,
222   sqlite3_result_error16,
223   sqlite3_result_int,
224   sqlite3_result_int64,
225   sqlite3_result_null,
226   sqlite3_result_text,
227   sqlite3_result_text16,
228   sqlite3_result_text16be,
229   sqlite3_result_text16le,
230   sqlite3_result_value,
231   sqlite3_rollback_hook,
232   sqlite3_set_authorizer,
233   sqlite3_set_auxdata,
234   sqlite3_snprintf,
235   sqlite3_step,
236   sqlite3_table_column_metadata,
237 #ifndef SQLITE_OMIT_DEPRECATED
238   sqlite3_thread_cleanup,
239 #else
240   0,
241 #endif
242   sqlite3_total_changes,
243   sqlite3_trace,
244 #ifndef SQLITE_OMIT_DEPRECATED
245   sqlite3_transfer_bindings,
246 #else
247   0,
248 #endif
249   sqlite3_update_hook,
250   sqlite3_user_data,
251   sqlite3_value_blob,
252   sqlite3_value_bytes,
253   sqlite3_value_bytes16,
254   sqlite3_value_double,
255   sqlite3_value_int,
256   sqlite3_value_int64,
257   sqlite3_value_numeric_type,
258   sqlite3_value_text,
259   sqlite3_value_text16,
260   sqlite3_value_text16be,
261   sqlite3_value_text16le,
262   sqlite3_value_type,
263   sqlite3_vmprintf,
264   /*
265   ** The original API set ends here.  All extensions can call any
266   ** of the APIs above provided that the pointer is not NULL.  But
267   ** before calling APIs that follow, extension should check the
268   ** sqlite3_libversion_number() to make sure they are dealing with
269   ** a library that is new enough to support that API.
270   *************************************************************************
271   */
272   sqlite3_overload_function,
273 
274   /*
275   ** Added after 3.3.13
276   */
277   sqlite3_prepare_v2,
278   sqlite3_prepare16_v2,
279   sqlite3_clear_bindings,
280 
281   /*
282   ** Added for 3.4.1
283   */
284   sqlite3_create_module_v2,
285 
286   /*
287   ** Added for 3.5.0
288   */
289   sqlite3_bind_zeroblob,
290   sqlite3_blob_bytes,
291   sqlite3_blob_close,
292   sqlite3_blob_open,
293   sqlite3_blob_read,
294   sqlite3_blob_write,
295   sqlite3_create_collation_v2,
296   sqlite3_file_control,
297   sqlite3_memory_highwater,
298   sqlite3_memory_used,
299 #ifdef SQLITE_MUTEX_OMIT
300   0,
301   0,
302   0,
303   0,
304   0,
305 #else
306   sqlite3_mutex_alloc,
307   sqlite3_mutex_enter,
308   sqlite3_mutex_free,
309   sqlite3_mutex_leave,
310   sqlite3_mutex_try,
311 #endif
312   sqlite3_open_v2,
313   sqlite3_release_memory,
314   sqlite3_result_error_nomem,
315   sqlite3_result_error_toobig,
316   sqlite3_sleep,
317   sqlite3_soft_heap_limit,
318   sqlite3_vfs_find,
319   sqlite3_vfs_register,
320   sqlite3_vfs_unregister,
321 
322   /*
323   ** Added for 3.5.8
324   */
325   sqlite3_threadsafe,
326   sqlite3_result_zeroblob,
327   sqlite3_result_error_code,
328   sqlite3_test_control,
329   sqlite3_randomness,
330   sqlite3_context_db_handle,
331 
332   /*
333   ** Added for 3.6.0
334   */
335   sqlite3_extended_result_codes,
336   sqlite3_limit,
337   sqlite3_next_stmt,
338   sqlite3_sql,
339   sqlite3_status,
340 
341   /*
342   ** Added for 3.7.4
343   */
344   sqlite3_backup_finish,
345   sqlite3_backup_init,
346   sqlite3_backup_pagecount,
347   sqlite3_backup_remaining,
348   sqlite3_backup_step,
349 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
350   sqlite3_compileoption_get,
351   sqlite3_compileoption_used,
352 #else
353   0,
354   0,
355 #endif
356   sqlite3_create_function_v2,
357   sqlite3_db_config,
358   sqlite3_db_mutex,
359   sqlite3_db_status,
360   sqlite3_extended_errcode,
361   sqlite3_log,
362   sqlite3_soft_heap_limit64,
363   sqlite3_sourceid,
364   sqlite3_stmt_status,
365   sqlite3_strnicmp,
366 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
367   sqlite3_unlock_notify,
368 #else
369   0,
370 #endif
371 #ifndef SQLITE_OMIT_WAL
372   sqlite3_wal_autocheckpoint,
373   sqlite3_wal_checkpoint,
374   sqlite3_wal_hook,
375 #else
376   0,
377   0,
378   0,
379 #endif
380   sqlite3_blob_reopen,
381   sqlite3_vtab_config,
382   sqlite3_vtab_on_conflict,
383   sqlite3_close_v2,
384   sqlite3_db_filename,
385   sqlite3_db_readonly,
386   sqlite3_db_release_memory,
387   sqlite3_errstr,
388   sqlite3_stmt_busy,
389   sqlite3_stmt_readonly,
390   sqlite3_stricmp,
391   sqlite3_uri_boolean,
392   sqlite3_uri_int64,
393   sqlite3_uri_parameter,
394   sqlite3_vsnprintf,
395   sqlite3_wal_checkpoint_v2,
396   /* Version 3.8.7 and later */
397   sqlite3_auto_extension,
398   sqlite3_bind_blob64,
399   sqlite3_bind_text64,
400   sqlite3_cancel_auto_extension,
401   sqlite3_load_extension,
402   sqlite3_malloc64,
403   sqlite3_msize,
404   sqlite3_realloc64,
405   sqlite3_reset_auto_extension,
406   sqlite3_result_blob64,
407   sqlite3_result_text64,
408   sqlite3_strglob,
409   /* Version 3.8.11 and later */
410   (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
411   sqlite3_value_free,
412   sqlite3_result_zeroblob64,
413   sqlite3_bind_zeroblob64,
414   /* Version 3.9.0 and later */
415   sqlite3_value_subtype,
416   sqlite3_result_subtype,
417   /* Version 3.10.0 and later */
418   sqlite3_status64,
419   sqlite3_strlike,
420   sqlite3_db_cacheflush,
421   /* Version 3.12.0 and later */
422   sqlite3_system_errno,
423   /* Version 3.14.0 and later */
424   sqlite3_trace_v2,
425   sqlite3_expanded_sql,
426   /* Version 3.18.0 and later */
427   sqlite3_set_last_insert_rowid,
428   /* Version 3.20.0 and later */
429   sqlite3_prepare_v3,
430   sqlite3_prepare16_v3,
431   sqlite3_bind_pointer,
432   sqlite3_result_pointer,
433   sqlite3_value_pointer,
434   /* Version 3.22.0 and later */
435   sqlite3_vtab_nochange,
436   sqlite3_value_nochange,
437   sqlite3_vtab_collation,
438   /* Version 3.24.0 and later */
439   sqlite3_keyword_count,
440   sqlite3_keyword_name,
441   sqlite3_keyword_check,
442   sqlite3_str_new,
443   sqlite3_str_finish,
444   sqlite3_str_appendf,
445   sqlite3_str_vappendf,
446   sqlite3_str_append,
447   sqlite3_str_appendall,
448   sqlite3_str_appendchar,
449   sqlite3_str_reset,
450   sqlite3_str_errcode,
451   sqlite3_str_length,
452   sqlite3_str_value
453 };
454 
455 /*
456 ** Attempt to load an SQLite extension library contained in the file
457 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
458 ** default entry point name (sqlite3_extension_init) is used.  Use
459 ** of the default name is recommended.
460 **
461 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
462 **
463 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
464 ** error message text.  The calling function should free this memory
465 ** by calling sqlite3DbFree(db, ).
466 */
467 static int sqlite3LoadExtension(
468   sqlite3 *db,          /* Load the extension into this database connection */
469   const char *zFile,    /* Name of the shared library containing extension */
470   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
471   char **pzErrMsg       /* Put error message here if not 0 */
472 ){
473   sqlite3_vfs *pVfs = db->pVfs;
474   void *handle;
475   sqlite3_loadext_entry xInit;
476   char *zErrmsg = 0;
477   const char *zEntry;
478   char *zAltEntry = 0;
479   void **aHandle;
480   u64 nMsg = 300 + sqlite3Strlen30(zFile);
481   int ii;
482   int rc;
483 
484   /* Shared library endings to try if zFile cannot be loaded as written */
485   static const char *azEndings[] = {
486 #if SQLITE_OS_WIN
487      "dll"
488 #elif defined(__APPLE__)
489      "dylib"
490 #else
491      "so"
492 #endif
493   };
494 
495 
496   if( pzErrMsg ) *pzErrMsg = 0;
497 
498   /* Ticket #1863.  To avoid a creating security problems for older
499   ** applications that relink against newer versions of SQLite, the
500   ** ability to run load_extension is turned off by default.  One
501   ** must call either sqlite3_enable_load_extension(db) or
502   ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
503   ** to turn on extension loading.
504   */
505   if( (db->flags & SQLITE_LoadExtension)==0 ){
506     if( pzErrMsg ){
507       *pzErrMsg = sqlite3_mprintf("not authorized");
508     }
509     return SQLITE_ERROR;
510   }
511 
512   zEntry = zProc ? zProc : "sqlite3_extension_init";
513 
514   handle = sqlite3OsDlOpen(pVfs, zFile);
515 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
516   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
517     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
518     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
519     handle = sqlite3OsDlOpen(pVfs, zAltFile);
520     sqlite3_free(zAltFile);
521   }
522 #endif
523   if( handle==0 ){
524     if( pzErrMsg ){
525       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
526       if( zErrmsg ){
527         sqlite3_snprintf(nMsg, zErrmsg,
528             "unable to open shared library [%s]", zFile);
529         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
530       }
531     }
532     return SQLITE_ERROR;
533   }
534   xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
535 
536   /* If no entry point was specified and the default legacy
537   ** entry point name "sqlite3_extension_init" was not found, then
538   ** construct an entry point name "sqlite3_X_init" where the X is
539   ** replaced by the lowercase value of every ASCII alphabetic
540   ** character in the filename after the last "/" upto the first ".",
541   ** and eliding the first three characters if they are "lib".
542   ** Examples:
543   **
544   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
545   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
546   */
547   if( xInit==0 && zProc==0 ){
548     int iFile, iEntry, c;
549     int ncFile = sqlite3Strlen30(zFile);
550     zAltEntry = sqlite3_malloc64(ncFile+30);
551     if( zAltEntry==0 ){
552       sqlite3OsDlClose(pVfs, handle);
553       return SQLITE_NOMEM_BKPT;
554     }
555     memcpy(zAltEntry, "sqlite3_", 8);
556     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
557     iFile++;
558     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
559     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
560       if( sqlite3Isalpha(c) ){
561         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
562       }
563     }
564     memcpy(zAltEntry+iEntry, "_init", 6);
565     zEntry = zAltEntry;
566     xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
567   }
568   if( xInit==0 ){
569     if( pzErrMsg ){
570       nMsg += sqlite3Strlen30(zEntry);
571       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
572       if( zErrmsg ){
573         sqlite3_snprintf(nMsg, zErrmsg,
574             "no entry point [%s] in shared library [%s]", zEntry, zFile);
575         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
576       }
577     }
578     sqlite3OsDlClose(pVfs, handle);
579     sqlite3_free(zAltEntry);
580     return SQLITE_ERROR;
581   }
582   sqlite3_free(zAltEntry);
583   rc = xInit(db, &zErrmsg, &sqlite3Apis);
584   if( rc ){
585     if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
586     if( pzErrMsg ){
587       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
588     }
589     sqlite3_free(zErrmsg);
590     sqlite3OsDlClose(pVfs, handle);
591     return SQLITE_ERROR;
592   }
593 
594   /* Append the new shared library handle to the db->aExtension array. */
595   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
596   if( aHandle==0 ){
597     return SQLITE_NOMEM_BKPT;
598   }
599   if( db->nExtension>0 ){
600     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
601   }
602   sqlite3DbFree(db, db->aExtension);
603   db->aExtension = aHandle;
604 
605   db->aExtension[db->nExtension++] = handle;
606   return SQLITE_OK;
607 }
608 int sqlite3_load_extension(
609   sqlite3 *db,          /* Load the extension into this database connection */
610   const char *zFile,    /* Name of the shared library containing extension */
611   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
612   char **pzErrMsg       /* Put error message here if not 0 */
613 ){
614   int rc;
615   sqlite3_mutex_enter(db->mutex);
616   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
617   rc = sqlite3ApiExit(db, rc);
618   sqlite3_mutex_leave(db->mutex);
619   return rc;
620 }
621 
622 /*
623 ** Call this routine when the database connection is closing in order
624 ** to clean up loaded extensions
625 */
626 void sqlite3CloseExtensions(sqlite3 *db){
627   int i;
628   assert( sqlite3_mutex_held(db->mutex) );
629   for(i=0; i<db->nExtension; i++){
630     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
631   }
632   sqlite3DbFree(db, db->aExtension);
633 }
634 
635 /*
636 ** Enable or disable extension loading.  Extension loading is disabled by
637 ** default so as not to open security holes in older applications.
638 */
639 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
640   sqlite3_mutex_enter(db->mutex);
641   if( onoff ){
642     db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
643   }else{
644     db->flags &= ~(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
645   }
646   sqlite3_mutex_leave(db->mutex);
647   return SQLITE_OK;
648 }
649 
650 #endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
651 
652 /*
653 ** The following object holds the list of automatically loaded
654 ** extensions.
655 **
656 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
657 ** mutex must be held while accessing this list.
658 */
659 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
660 static SQLITE_WSD struct sqlite3AutoExtList {
661   u32 nExt;              /* Number of entries in aExt[] */
662   void (**aExt)(void);   /* Pointers to the extension init functions */
663 } sqlite3Autoext = { 0, 0 };
664 
665 /* The "wsdAutoext" macro will resolve to the autoextension
666 ** state vector.  If writable static data is unsupported on the target,
667 ** we have to locate the state vector at run-time.  In the more common
668 ** case where writable static data is supported, wsdStat can refer directly
669 ** to the "sqlite3Autoext" state vector declared above.
670 */
671 #ifdef SQLITE_OMIT_WSD
672 # define wsdAutoextInit \
673   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
674 # define wsdAutoext x[0]
675 #else
676 # define wsdAutoextInit
677 # define wsdAutoext sqlite3Autoext
678 #endif
679 
680 
681 /*
682 ** Register a statically linked extension that is automatically
683 ** loaded by every new database connection.
684 */
685 int sqlite3_auto_extension(
686   void (*xInit)(void)
687 ){
688   int rc = SQLITE_OK;
689 #ifndef SQLITE_OMIT_AUTOINIT
690   rc = sqlite3_initialize();
691   if( rc ){
692     return rc;
693   }else
694 #endif
695   {
696     u32 i;
697 #if SQLITE_THREADSAFE
698     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
699 #endif
700     wsdAutoextInit;
701     sqlite3_mutex_enter(mutex);
702     for(i=0; i<wsdAutoext.nExt; i++){
703       if( wsdAutoext.aExt[i]==xInit ) break;
704     }
705     if( i==wsdAutoext.nExt ){
706       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
707       void (**aNew)(void);
708       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
709       if( aNew==0 ){
710         rc = SQLITE_NOMEM_BKPT;
711       }else{
712         wsdAutoext.aExt = aNew;
713         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
714         wsdAutoext.nExt++;
715       }
716     }
717     sqlite3_mutex_leave(mutex);
718     assert( (rc&0xff)==rc );
719     return rc;
720   }
721 }
722 
723 /*
724 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
725 ** set of routines that is invoked for each new database connection, if it
726 ** is currently on the list.  If xInit is not on the list, then this
727 ** routine is a no-op.
728 **
729 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
730 ** was not on the list.
731 */
732 int sqlite3_cancel_auto_extension(
733   void (*xInit)(void)
734 ){
735 #if SQLITE_THREADSAFE
736   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
737 #endif
738   int i;
739   int n = 0;
740   wsdAutoextInit;
741   sqlite3_mutex_enter(mutex);
742   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
743     if( wsdAutoext.aExt[i]==xInit ){
744       wsdAutoext.nExt--;
745       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
746       n++;
747       break;
748     }
749   }
750   sqlite3_mutex_leave(mutex);
751   return n;
752 }
753 
754 /*
755 ** Reset the automatic extension loading mechanism.
756 */
757 void sqlite3_reset_auto_extension(void){
758 #ifndef SQLITE_OMIT_AUTOINIT
759   if( sqlite3_initialize()==SQLITE_OK )
760 #endif
761   {
762 #if SQLITE_THREADSAFE
763     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
764 #endif
765     wsdAutoextInit;
766     sqlite3_mutex_enter(mutex);
767     sqlite3_free(wsdAutoext.aExt);
768     wsdAutoext.aExt = 0;
769     wsdAutoext.nExt = 0;
770     sqlite3_mutex_leave(mutex);
771   }
772 }
773 
774 /*
775 ** Load all automatic extensions.
776 **
777 ** If anything goes wrong, set an error in the database connection.
778 */
779 void sqlite3AutoLoadExtensions(sqlite3 *db){
780   u32 i;
781   int go = 1;
782   int rc;
783   sqlite3_loadext_entry xInit;
784 
785   wsdAutoextInit;
786   if( wsdAutoext.nExt==0 ){
787     /* Common case: early out without every having to acquire a mutex */
788     return;
789   }
790   for(i=0; go; i++){
791     char *zErrmsg;
792 #if SQLITE_THREADSAFE
793     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
794 #endif
795 #ifdef SQLITE_OMIT_LOAD_EXTENSION
796     const sqlite3_api_routines *pThunk = 0;
797 #else
798     const sqlite3_api_routines *pThunk = &sqlite3Apis;
799 #endif
800     sqlite3_mutex_enter(mutex);
801     if( i>=wsdAutoext.nExt ){
802       xInit = 0;
803       go = 0;
804     }else{
805       xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
806     }
807     sqlite3_mutex_leave(mutex);
808     zErrmsg = 0;
809     if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
810       sqlite3ErrorWithMsg(db, rc,
811             "automatic extension loading failed: %s", zErrmsg);
812       go = 0;
813     }
814     sqlite3_free(zErrmsg);
815   }
816 }
817