xref: /sqlite-3.40.0/src/loadext.c (revision 8c53b4e7) 
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 };
463 
464 /*
465 ** Attempt to load an SQLite extension library contained in the file
466 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
467 ** default entry point name (sqlite3_extension_init) is used.  Use
468 ** of the default name is recommended.
469 **
470 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
471 **
472 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
473 ** error message text.  The calling function should free this memory
474 ** by calling sqlite3DbFree(db, ).
475 */
476 static int sqlite3LoadExtension(
477   sqlite3 *db,          /* Load the extension into this database connection */
478   const char *zFile,    /* Name of the shared library containing extension */
479   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
480   char **pzErrMsg       /* Put error message here if not 0 */
481 ){
482   sqlite3_vfs *pVfs = db->pVfs;
483   void *handle;
484   sqlite3_loadext_entry xInit;
485   char *zErrmsg = 0;
486   const char *zEntry;
487   char *zAltEntry = 0;
488   void **aHandle;
489   u64 nMsg = 300 + sqlite3Strlen30(zFile);
490   int ii;
491   int rc;
492 
493   /* Shared library endings to try if zFile cannot be loaded as written */
494   static const char *azEndings[] = {
495 #if SQLITE_OS_WIN
496      "dll"
497 #elif defined(__APPLE__)
498      "dylib"
499 #else
500      "so"
501 #endif
502   };
503 
504 
505   if( pzErrMsg ) *pzErrMsg = 0;
506 
507   /* Ticket #1863.  To avoid a creating security problems for older
508   ** applications that relink against newer versions of SQLite, the
509   ** ability to run load_extension is turned off by default.  One
510   ** must call either sqlite3_enable_load_extension(db) or
511   ** sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, 1, 0)
512   ** to turn on extension loading.
513   */
514   if( (db->flags & SQLITE_LoadExtension)==0 ){
515     if( pzErrMsg ){
516       *pzErrMsg = sqlite3_mprintf("not authorized");
517     }
518     return SQLITE_ERROR;
519   }
520 
521   zEntry = zProc ? zProc : "sqlite3_extension_init";
522 
523   handle = sqlite3OsDlOpen(pVfs, zFile);
524 #if SQLITE_OS_UNIX || SQLITE_OS_WIN
525   for(ii=0; ii<ArraySize(azEndings) && handle==0; ii++){
526     char *zAltFile = sqlite3_mprintf("%s.%s", zFile, azEndings[ii]);
527     if( zAltFile==0 ) return SQLITE_NOMEM_BKPT;
528     handle = sqlite3OsDlOpen(pVfs, zAltFile);
529     sqlite3_free(zAltFile);
530   }
531 #endif
532   if( handle==0 ){
533     if( pzErrMsg ){
534       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
535       if( zErrmsg ){
536         sqlite3_snprintf(nMsg, zErrmsg,
537             "unable to open shared library [%s]", zFile);
538         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
539       }
540     }
541     return SQLITE_ERROR;
542   }
543   xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
544 
545   /* If no entry point was specified and the default legacy
546   ** entry point name "sqlite3_extension_init" was not found, then
547   ** construct an entry point name "sqlite3_X_init" where the X is
548   ** replaced by the lowercase value of every ASCII alphabetic
549   ** character in the filename after the last "/" upto the first ".",
550   ** and eliding the first three characters if they are "lib".
551   ** Examples:
552   **
553   **    /usr/local/lib/libExample5.4.3.so ==>  sqlite3_example_init
554   **    C:/lib/mathfuncs.dll              ==>  sqlite3_mathfuncs_init
555   */
556   if( xInit==0 && zProc==0 ){
557     int iFile, iEntry, c;
558     int ncFile = sqlite3Strlen30(zFile);
559     zAltEntry = sqlite3_malloc64(ncFile+30);
560     if( zAltEntry==0 ){
561       sqlite3OsDlClose(pVfs, handle);
562       return SQLITE_NOMEM_BKPT;
563     }
564     memcpy(zAltEntry, "sqlite3_", 8);
565     for(iFile=ncFile-1; iFile>=0 && zFile[iFile]!='/'; iFile--){}
566     iFile++;
567     if( sqlite3_strnicmp(zFile+iFile, "lib", 3)==0 ) iFile += 3;
568     for(iEntry=8; (c = zFile[iFile])!=0 && c!='.'; iFile++){
569       if( sqlite3Isalpha(c) ){
570         zAltEntry[iEntry++] = (char)sqlite3UpperToLower[(unsigned)c];
571       }
572     }
573     memcpy(zAltEntry+iEntry, "_init", 6);
574     zEntry = zAltEntry;
575     xInit = (sqlite3_loadext_entry)sqlite3OsDlSym(pVfs, handle, zEntry);
576   }
577   if( xInit==0 ){
578     if( pzErrMsg ){
579       nMsg += sqlite3Strlen30(zEntry);
580       *pzErrMsg = zErrmsg = sqlite3_malloc64(nMsg);
581       if( zErrmsg ){
582         sqlite3_snprintf(nMsg, zErrmsg,
583             "no entry point [%s] in shared library [%s]", zEntry, zFile);
584         sqlite3OsDlError(pVfs, nMsg-1, zErrmsg);
585       }
586     }
587     sqlite3OsDlClose(pVfs, handle);
588     sqlite3_free(zAltEntry);
589     return SQLITE_ERROR;
590   }
591   sqlite3_free(zAltEntry);
592   rc = xInit(db, &zErrmsg, &sqlite3Apis);
593   if( rc ){
594     if( rc==SQLITE_OK_LOAD_PERMANENTLY ) return SQLITE_OK;
595     if( pzErrMsg ){
596       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
597     }
598     sqlite3_free(zErrmsg);
599     sqlite3OsDlClose(pVfs, handle);
600     return SQLITE_ERROR;
601   }
602 
603   /* Append the new shared library handle to the db->aExtension array. */
604   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));
605   if( aHandle==0 ){
606     return SQLITE_NOMEM_BKPT;
607   }
608   if( db->nExtension>0 ){
609     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);
610   }
611   sqlite3DbFree(db, db->aExtension);
612   db->aExtension = aHandle;
613 
614   db->aExtension[db->nExtension++] = handle;
615   return SQLITE_OK;
616 }
617 int sqlite3_load_extension(
618   sqlite3 *db,          /* Load the extension into this database connection */
619   const char *zFile,    /* Name of the shared library containing extension */
620   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
621   char **pzErrMsg       /* Put error message here if not 0 */
622 ){
623   int rc;
624   sqlite3_mutex_enter(db->mutex);
625   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);
626   rc = sqlite3ApiExit(db, rc);
627   sqlite3_mutex_leave(db->mutex);
628   return rc;
629 }
630 
631 /*
632 ** Call this routine when the database connection is closing in order
633 ** to clean up loaded extensions
634 */
635 void sqlite3CloseExtensions(sqlite3 *db){
636   int i;
637   assert( sqlite3_mutex_held(db->mutex) );
638   for(i=0; i<db->nExtension; i++){
639     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);
640   }
641   sqlite3DbFree(db, db->aExtension);
642 }
643 
644 /*
645 ** Enable or disable extension loading.  Extension loading is disabled by
646 ** default so as not to open security holes in older applications.
647 */
648 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
649   sqlite3_mutex_enter(db->mutex);
650   if( onoff ){
651     db->flags |= SQLITE_LoadExtension|SQLITE_LoadExtFunc;
652   }else{
653     db->flags &= ~(SQLITE_LoadExtension|SQLITE_LoadExtFunc);
654   }
655   sqlite3_mutex_leave(db->mutex);
656   return SQLITE_OK;
657 }
658 
659 #endif /* !defined(SQLITE_OMIT_LOAD_EXTENSION) */
660 
661 /*
662 ** The following object holds the list of automatically loaded
663 ** extensions.
664 **
665 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER
666 ** mutex must be held while accessing this list.
667 */
668 typedef struct sqlite3AutoExtList sqlite3AutoExtList;
669 static SQLITE_WSD struct sqlite3AutoExtList {
670   u32 nExt;              /* Number of entries in aExt[] */
671   void (**aExt)(void);   /* Pointers to the extension init functions */
672 } sqlite3Autoext = { 0, 0 };
673 
674 /* The "wsdAutoext" macro will resolve to the autoextension
675 ** state vector.  If writable static data is unsupported on the target,
676 ** we have to locate the state vector at run-time.  In the more common
677 ** case where writable static data is supported, wsdStat can refer directly
678 ** to the "sqlite3Autoext" state vector declared above.
679 */
680 #ifdef SQLITE_OMIT_WSD
681 # define wsdAutoextInit \
682   sqlite3AutoExtList *x = &GLOBAL(sqlite3AutoExtList,sqlite3Autoext)
683 # define wsdAutoext x[0]
684 #else
685 # define wsdAutoextInit
686 # define wsdAutoext sqlite3Autoext
687 #endif
688 
689 
690 /*
691 ** Register a statically linked extension that is automatically
692 ** loaded by every new database connection.
693 */
694 int sqlite3_auto_extension(
695   void (*xInit)(void)
696 ){
697   int rc = SQLITE_OK;
698 #ifndef SQLITE_OMIT_AUTOINIT
699   rc = sqlite3_initialize();
700   if( rc ){
701     return rc;
702   }else
703 #endif
704   {
705     u32 i;
706 #if SQLITE_THREADSAFE
707     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
708 #endif
709     wsdAutoextInit;
710     sqlite3_mutex_enter(mutex);
711     for(i=0; i<wsdAutoext.nExt; i++){
712       if( wsdAutoext.aExt[i]==xInit ) break;
713     }
714     if( i==wsdAutoext.nExt ){
715       u64 nByte = (wsdAutoext.nExt+1)*sizeof(wsdAutoext.aExt[0]);
716       void (**aNew)(void);
717       aNew = sqlite3_realloc64(wsdAutoext.aExt, nByte);
718       if( aNew==0 ){
719         rc = SQLITE_NOMEM_BKPT;
720       }else{
721         wsdAutoext.aExt = aNew;
722         wsdAutoext.aExt[wsdAutoext.nExt] = xInit;
723         wsdAutoext.nExt++;
724       }
725     }
726     sqlite3_mutex_leave(mutex);
727     assert( (rc&0xff)==rc );
728     return rc;
729   }
730 }
731 
732 /*
733 ** Cancel a prior call to sqlite3_auto_extension.  Remove xInit from the
734 ** set of routines that is invoked for each new database connection, if it
735 ** is currently on the list.  If xInit is not on the list, then this
736 ** routine is a no-op.
737 **
738 ** Return 1 if xInit was found on the list and removed.  Return 0 if xInit
739 ** was not on the list.
740 */
741 int sqlite3_cancel_auto_extension(
742   void (*xInit)(void)
743 ){
744 #if SQLITE_THREADSAFE
745   sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
746 #endif
747   int i;
748   int n = 0;
749   wsdAutoextInit;
750   sqlite3_mutex_enter(mutex);
751   for(i=(int)wsdAutoext.nExt-1; i>=0; i--){
752     if( wsdAutoext.aExt[i]==xInit ){
753       wsdAutoext.nExt--;
754       wsdAutoext.aExt[i] = wsdAutoext.aExt[wsdAutoext.nExt];
755       n++;
756       break;
757     }
758   }
759   sqlite3_mutex_leave(mutex);
760   return n;
761 }
762 
763 /*
764 ** Reset the automatic extension loading mechanism.
765 */
766 void sqlite3_reset_auto_extension(void){
767 #ifndef SQLITE_OMIT_AUTOINIT
768   if( sqlite3_initialize()==SQLITE_OK )
769 #endif
770   {
771 #if SQLITE_THREADSAFE
772     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
773 #endif
774     wsdAutoextInit;
775     sqlite3_mutex_enter(mutex);
776     sqlite3_free(wsdAutoext.aExt);
777     wsdAutoext.aExt = 0;
778     wsdAutoext.nExt = 0;
779     sqlite3_mutex_leave(mutex);
780   }
781 }
782 
783 /*
784 ** Load all automatic extensions.
785 **
786 ** If anything goes wrong, set an error in the database connection.
787 */
788 void sqlite3AutoLoadExtensions(sqlite3 *db){
789   u32 i;
790   int go = 1;
791   int rc;
792   sqlite3_loadext_entry xInit;
793 
794   wsdAutoextInit;
795   if( wsdAutoext.nExt==0 ){
796     /* Common case: early out without every having to acquire a mutex */
797     return;
798   }
799   for(i=0; go; i++){
800     char *zErrmsg;
801 #if SQLITE_THREADSAFE
802     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
803 #endif
804 #ifdef SQLITE_OMIT_LOAD_EXTENSION
805     const sqlite3_api_routines *pThunk = 0;
806 #else
807     const sqlite3_api_routines *pThunk = &sqlite3Apis;
808 #endif
809     sqlite3_mutex_enter(mutex);
810     if( i>=wsdAutoext.nExt ){
811       xInit = 0;
812       go = 0;
813     }else{
814       xInit = (sqlite3_loadext_entry)wsdAutoext.aExt[i];
815     }
816     sqlite3_mutex_leave(mutex);
817     zErrmsg = 0;
818     if( xInit && (rc = xInit(db, &zErrmsg, pThunk))!=0 ){
819       sqlite3ErrorWithMsg(db, rc,
820             "automatic extension loading failed: %s", zErrmsg);
821       go = 0;
822     }
823     sqlite3_free(zErrmsg);
824   }
825 }
826