xref: /sqlite-3.40.0/src/loadext.c (revision 9f8a4b43)
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 #ifndef SQLITE_OMIT_LOAD_EXTENSION
16 
17 #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */
18 #include "sqlite3ext.h"
19 #include "sqliteInt.h"
20 #include "os.h"
21 #include <string.h>
22 #include <ctype.h>
23 
24 /*
25 ** Some API routines are omitted when various features are
26 ** excluded from a build of SQLite.  Substitute a NULL pointer
27 ** for any missing APIs.
28 */
29 #ifndef SQLITE_ENABLE_COLUMN_METADATA
30 # define sqlite3_column_database_name   0
31 # define sqlite3_column_database_name16 0
32 # define sqlite3_column_table_name      0
33 # define sqlite3_column_table_name16    0
34 # define sqlite3_column_origin_name     0
35 # define sqlite3_column_origin_name16   0
36 # define sqlite3_table_column_metadata  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_PROGRESS_CALLBACK
74 # define sqlite3_progress_handler 0
75 #endif
76 
77 #ifdef SQLITE_OMIT_VIRTUALTABLE
78 # define sqlite3_create_module 0
79 # define sqlite3_create_module_v2 0
80 # define sqlite3_declare_vtab 0
81 #endif
82 
83 #ifdef SQLITE_OMIT_SHARED_CACHE
84 # define sqlite3_enable_shared_cache 0
85 #endif
86 
87 #ifdef SQLITE_OMIT_TRACE
88 # define sqlite3_profile       0
89 # define sqlite3_trace         0
90 #endif
91 
92 #ifdef SQLITE_OMIT_GET_TABLE
93 # define sqlite3_free_table    0
94 # define sqlite3_get_table     0
95 #endif
96 
97 /*
98 ** The following structure contains pointers to all SQLite API routines.
99 ** A pointer to this structure is passed into extensions when they are
100 ** loaded so that the extension can make calls back into the SQLite
101 ** library.
102 **
103 ** When adding new APIs, add them to the bottom of this structure
104 ** in order to preserve backwards compatibility.
105 **
106 ** Extensions that use newer APIs should first call the
107 ** sqlite3_libversion_number() to make sure that the API they
108 ** intend to use is supported by the library.  Extensions should
109 ** also check to make sure that the pointer to the function is
110 ** not NULL before calling it.
111 */
112 const sqlite3_api_routines sqlite3_apis = {
113   sqlite3_aggregate_context,
114   sqlite3_aggregate_count,
115   sqlite3_bind_blob,
116   sqlite3_bind_double,
117   sqlite3_bind_int,
118   sqlite3_bind_int64,
119   sqlite3_bind_null,
120   sqlite3_bind_parameter_count,
121   sqlite3_bind_parameter_index,
122   sqlite3_bind_parameter_name,
123   sqlite3_bind_text,
124   sqlite3_bind_text16,
125   sqlite3_bind_value,
126   sqlite3_busy_handler,
127   sqlite3_busy_timeout,
128   sqlite3_changes,
129   sqlite3_close,
130   sqlite3_collation_needed,
131   sqlite3_collation_needed16,
132   sqlite3_column_blob,
133   sqlite3_column_bytes,
134   sqlite3_column_bytes16,
135   sqlite3_column_count,
136   sqlite3_column_database_name,
137   sqlite3_column_database_name16,
138   sqlite3_column_decltype,
139   sqlite3_column_decltype16,
140   sqlite3_column_double,
141   sqlite3_column_int,
142   sqlite3_column_int64,
143   sqlite3_column_name,
144   sqlite3_column_name16,
145   sqlite3_column_origin_name,
146   sqlite3_column_origin_name16,
147   sqlite3_column_table_name,
148   sqlite3_column_table_name16,
149   sqlite3_column_text,
150   sqlite3_column_text16,
151   sqlite3_column_type,
152   sqlite3_column_value,
153   sqlite3_commit_hook,
154   sqlite3_complete,
155   sqlite3_complete16,
156   sqlite3_create_collation,
157   sqlite3_create_collation16,
158   sqlite3_create_function,
159   sqlite3_create_function16,
160   sqlite3_create_module,
161   sqlite3_data_count,
162   sqlite3_db_handle,
163   sqlite3_declare_vtab,
164   sqlite3_enable_shared_cache,
165   sqlite3_errcode,
166   sqlite3_errmsg,
167   sqlite3_errmsg16,
168   sqlite3_exec,
169   sqlite3_expired,
170   sqlite3_finalize,
171   sqlite3_free,
172   sqlite3_free_table,
173   sqlite3_get_autocommit,
174   sqlite3_get_auxdata,
175   sqlite3_get_table,
176   0,     /* Was sqlite3_global_recover(), but that function is deprecated */
177   sqlite3_interrupt,
178   sqlite3_last_insert_rowid,
179   sqlite3_libversion,
180   sqlite3_libversion_number,
181   sqlite3_malloc,
182   sqlite3_mprintf,
183   sqlite3_open,
184   sqlite3_open16,
185   sqlite3_prepare,
186   sqlite3_prepare16,
187   sqlite3_profile,
188   sqlite3_progress_handler,
189   sqlite3_realloc,
190   sqlite3_reset,
191   sqlite3_result_blob,
192   sqlite3_result_double,
193   sqlite3_result_error,
194   sqlite3_result_error16,
195   sqlite3_result_int,
196   sqlite3_result_int64,
197   sqlite3_result_null,
198   sqlite3_result_text,
199   sqlite3_result_text16,
200   sqlite3_result_text16be,
201   sqlite3_result_text16le,
202   sqlite3_result_value,
203   sqlite3_rollback_hook,
204   sqlite3_set_authorizer,
205   sqlite3_set_auxdata,
206   sqlite3_snprintf,
207   sqlite3_step,
208   sqlite3_table_column_metadata,
209   sqlite3_thread_cleanup,
210   sqlite3_total_changes,
211   sqlite3_trace,
212   sqlite3_transfer_bindings,
213   sqlite3_update_hook,
214   sqlite3_user_data,
215   sqlite3_value_blob,
216   sqlite3_value_bytes,
217   sqlite3_value_bytes16,
218   sqlite3_value_double,
219   sqlite3_value_int,
220   sqlite3_value_int64,
221   sqlite3_value_numeric_type,
222   sqlite3_value_text,
223   sqlite3_value_text16,
224   sqlite3_value_text16be,
225   sqlite3_value_text16le,
226   sqlite3_value_type,
227   sqlite3_vmprintf,
228   /*
229   ** The original API set ends here.  All extensions can call any
230   ** of the APIs above provided that the pointer is not NULL.  But
231   ** before calling APIs that follow, extension should check the
232   ** sqlite3_libversion_number() to make sure they are dealing with
233   ** a library that is new enough to support that API.
234   *************************************************************************
235   */
236   sqlite3_overload_function,
237 
238   /*
239   ** Added after 3.3.13
240   */
241   sqlite3_prepare_v2,
242   sqlite3_prepare16_v2,
243   sqlite3_clear_bindings,
244 
245   /*
246   ** Added for 3.4.1
247   */
248   sqlite3_create_module_v2,
249 
250 };
251 
252 /*
253 ** Attempt to load an SQLite extension library contained in the file
254 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
255 ** default entry point name (sqlite3_extension_init) is used.  Use
256 ** of the default name is recommended.
257 **
258 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
259 **
260 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
261 ** error message text.  The calling function should free this memory
262 ** by calling sqlite3_free().
263 */
264 int sqlite3_load_extension(
265   sqlite3 *db,          /* Load the extension into this database connection */
266   const char *zFile,    /* Name of the shared library containing extension */
267   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
268   char **pzErrMsg       /* Put error message here if not 0 */
269 ){
270   void *handle;
271   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
272   char *zErrmsg = 0;
273   void **aHandle;
274 
275   /* Ticket #1863.  To avoid a creating security problems for older
276   ** applications that relink against newer versions of SQLite, the
277   ** ability to run load_extension is turned off by default.  One
278   ** must call sqlite3_enable_load_extension() to turn on extension
279   ** loading.  Otherwise you get the following error.
280   */
281   if( (db->flags & SQLITE_LoadExtension)==0 ){
282     if( pzErrMsg ){
283       *pzErrMsg = sqlite3_mprintf("not authorized");
284     }
285     return SQLITE_ERROR;
286   }
287 
288   if( zProc==0 ){
289     zProc = "sqlite3_extension_init";
290   }
291 
292   handle = sqlite3OsDlopen(zFile);
293   if( handle==0 ){
294     if( pzErrMsg ){
295       *pzErrMsg = sqlite3_mprintf("unable to open shared library [%s]", zFile);
296     }
297     return SQLITE_ERROR;
298   }
299   xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
300                    sqlite3OsDlsym(handle, zProc);
301   if( xInit==0 ){
302     if( pzErrMsg ){
303        *pzErrMsg = sqlite3_mprintf("no entry point [%s] in shared library [%s]",
304                                    zProc, zFile);
305     }
306     sqlite3OsDlclose(handle);
307     return SQLITE_ERROR;
308   }else if( xInit(db, &zErrmsg, &sqlite3_apis) ){
309     if( pzErrMsg ){
310       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
311     }
312     sqlite3_free(zErrmsg);
313     sqlite3OsDlclose(handle);
314     return SQLITE_ERROR;
315   }
316 
317   /* Append the new shared library handle to the db->aExtension array. */
318   db->nExtension++;
319   aHandle = sqliteMalloc(sizeof(handle)*db->nExtension);
320   if( aHandle==0 ){
321     return SQLITE_NOMEM;
322   }
323   if( db->nExtension>0 ){
324     memcpy(aHandle, db->aExtension, sizeof(handle)*(db->nExtension-1));
325   }
326   sqliteFree(db->aExtension);
327   db->aExtension = aHandle;
328 
329   db->aExtension[db->nExtension-1] = handle;
330   return SQLITE_OK;
331 }
332 
333 /*
334 ** Call this routine when the database connection is closing in order
335 ** to clean up loaded extensions
336 */
337 void sqlite3CloseExtensions(sqlite3 *db){
338   int i;
339   for(i=0; i<db->nExtension; i++){
340     sqlite3OsDlclose(db->aExtension[i]);
341   }
342   sqliteFree(db->aExtension);
343 }
344 
345 /*
346 ** Enable or disable extension loading.  Extension loading is disabled by
347 ** default so as not to open security holes in older applications.
348 */
349 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
350   if( onoff ){
351     db->flags |= SQLITE_LoadExtension;
352   }else{
353     db->flags &= ~SQLITE_LoadExtension;
354   }
355   return SQLITE_OK;
356 }
357 
358 /*
359 ** A list of automatically loaded extensions.
360 **
361 ** This list is shared across threads, so be sure to hold the
362 ** mutex while accessing or changing it.
363 */
364 static int nAutoExtension = 0;
365 static void **aAutoExtension = 0;
366 
367 
368 /*
369 ** Register a statically linked extension that is automatically
370 ** loaded by every new database connection.
371 */
372 int sqlite3_auto_extension(void *xInit){
373   int i;
374   int rc = SQLITE_OK;
375   sqlite3OsEnterMutex();
376   for(i=0; i<nAutoExtension; i++){
377     if( aAutoExtension[i]==xInit ) break;
378   }
379   if( i==nAutoExtension ){
380     nAutoExtension++;
381     aAutoExtension = sqlite3Realloc( aAutoExtension,
382                                      nAutoExtension*sizeof(aAutoExtension[0]) );
383     if( aAutoExtension==0 ){
384       nAutoExtension = 0;
385       rc = SQLITE_NOMEM;
386     }else{
387       aAutoExtension[nAutoExtension-1] = xInit;
388     }
389   }
390   sqlite3OsLeaveMutex();
391   assert( (rc&0xff)==rc );
392   return rc;
393 }
394 
395 /*
396 ** Reset the automatic extension loading mechanism.
397 */
398 void sqlite3_reset_auto_extension(void){
399   sqlite3OsEnterMutex();
400   sqliteFree(aAutoExtension);
401   aAutoExtension = 0;
402   nAutoExtension = 0;
403   sqlite3OsLeaveMutex();
404 }
405 
406 /*
407 ** Load all automatic extensions.
408 */
409 int sqlite3AutoLoadExtensions(sqlite3 *db){
410   int i;
411   int go = 1;
412   int rc = SQLITE_OK;
413   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
414 
415   if( nAutoExtension==0 ){
416     /* Common case: early out without every having to acquire a mutex */
417     return SQLITE_OK;
418   }
419   for(i=0; go; i++){
420     char *zErrmsg = 0;
421     sqlite3OsEnterMutex();
422     if( i>=nAutoExtension ){
423       xInit = 0;
424       go = 0;
425     }else{
426       xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
427               aAutoExtension[i];
428     }
429     sqlite3OsLeaveMutex();
430     if( xInit && xInit(db, &zErrmsg, &sqlite3_apis) ){
431       sqlite3Error(db, SQLITE_ERROR,
432             "automatic extension loading failed: %s", zErrmsg);
433       go = 0;
434       rc = SQLITE_ERROR;
435     }
436   }
437   return rc;
438 }
439 
440 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
441