xref: /sqlite-3.40.0/src/loadext.c (revision 5665b3ea)
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_declare_vtab 0
80 #endif
81 
82 #ifdef SQLITE_OMIT_SHARED_CACHE
83 # define sqlite3_enable_shared_cache 0
84 #endif
85 
86 #ifdef SQLITE_OMIT_TRACE
87 # define sqlite3_profile       0
88 # define sqlite3_trace         0
89 #endif
90 
91 #ifdef SQLITE_OMIT_GET_TABLE
92 # define sqlite3_free_table    0
93 # define sqlite3_get_table     0
94 #endif
95 
96 /*
97 ** The following structure contains pointers to all SQLite API routines.
98 ** A pointer to this structure is passed into extensions when they are
99 ** loaded so that the extension can make calls back into the SQLite
100 ** library.
101 **
102 ** When adding new APIs, add them to the bottom of this structure
103 ** in order to preserve backwards compatibility.
104 **
105 ** Extensions that use newer APIs should first call the
106 ** sqlite3_libversion_number() to make sure that the API they
107 ** intend to use is supported by the library.  Extensions should
108 ** also check to make sure that the pointer to the function is
109 ** not NULL before calling it.
110 */
111 const sqlite3_api_routines sqlite3_apis = {
112   sqlite3_aggregate_context,
113   sqlite3_aggregate_count,
114   sqlite3_bind_blob,
115   sqlite3_bind_double,
116   sqlite3_bind_int,
117   sqlite3_bind_int64,
118   sqlite3_bind_null,
119   sqlite3_bind_parameter_count,
120   sqlite3_bind_parameter_index,
121   sqlite3_bind_parameter_name,
122   sqlite3_bind_text,
123   sqlite3_bind_text16,
124   sqlite3_bind_value,
125   sqlite3_busy_handler,
126   sqlite3_busy_timeout,
127   sqlite3_changes,
128   sqlite3_close,
129   sqlite3_collation_needed,
130   sqlite3_collation_needed16,
131   sqlite3_column_blob,
132   sqlite3_column_bytes,
133   sqlite3_column_bytes16,
134   sqlite3_column_count,
135   sqlite3_column_database_name,
136   sqlite3_column_database_name16,
137   sqlite3_column_decltype,
138   sqlite3_column_decltype16,
139   sqlite3_column_double,
140   sqlite3_column_int,
141   sqlite3_column_int64,
142   sqlite3_column_name,
143   sqlite3_column_name16,
144   sqlite3_column_origin_name,
145   sqlite3_column_origin_name16,
146   sqlite3_column_table_name,
147   sqlite3_column_table_name16,
148   sqlite3_column_text,
149   sqlite3_column_text16,
150   sqlite3_column_type,
151   sqlite3_column_value,
152   sqlite3_commit_hook,
153   sqlite3_complete,
154   sqlite3_complete16,
155   sqlite3_create_collation,
156   sqlite3_create_collation16,
157   sqlite3_create_function,
158   sqlite3_create_function16,
159   sqlite3_create_module,
160   sqlite3_create_module_v2,
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 /*
247 ** Attempt to load an SQLite extension library contained in the file
248 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a
249 ** default entry point name (sqlite3_extension_init) is used.  Use
250 ** of the default name is recommended.
251 **
252 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
253 **
254 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
255 ** error message text.  The calling function should free this memory
256 ** by calling sqlite3_free().
257 */
258 int sqlite3_load_extension(
259   sqlite3 *db,          /* Load the extension into this database connection */
260   const char *zFile,    /* Name of the shared library containing extension */
261   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */
262   char **pzErrMsg       /* Put error message here if not 0 */
263 ){
264   void *handle;
265   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
266   char *zErrmsg = 0;
267   void **aHandle;
268 
269   /* Ticket #1863.  To avoid a creating security problems for older
270   ** applications that relink against newer versions of SQLite, the
271   ** ability to run load_extension is turned off by default.  One
272   ** must call sqlite3_enable_load_extension() to turn on extension
273   ** loading.  Otherwise you get the following error.
274   */
275   if( (db->flags & SQLITE_LoadExtension)==0 ){
276     if( pzErrMsg ){
277       *pzErrMsg = sqlite3_mprintf("not authorized");
278     }
279     return SQLITE_ERROR;
280   }
281 
282   if( zProc==0 ){
283     zProc = "sqlite3_extension_init";
284   }
285 
286   handle = sqlite3OsDlopen(zFile);
287   if( handle==0 ){
288     if( pzErrMsg ){
289       *pzErrMsg = sqlite3_mprintf("unable to open shared library [%s]", zFile);
290     }
291     return SQLITE_ERROR;
292   }
293   xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
294                    sqlite3OsDlsym(handle, zProc);
295   if( xInit==0 ){
296     if( pzErrMsg ){
297        *pzErrMsg = sqlite3_mprintf("no entry point [%s] in shared library [%s]",
298                                    zProc, zFile);
299     }
300     sqlite3OsDlclose(handle);
301     return SQLITE_ERROR;
302   }else if( xInit(db, &zErrmsg, &sqlite3_apis) ){
303     if( pzErrMsg ){
304       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);
305     }
306     sqlite3_free(zErrmsg);
307     sqlite3OsDlclose(handle);
308     return SQLITE_ERROR;
309   }
310 
311   /* Append the new shared library handle to the db->aExtension array. */
312   db->nExtension++;
313   aHandle = sqliteMalloc(sizeof(handle)*db->nExtension);
314   if( aHandle==0 ){
315     return SQLITE_NOMEM;
316   }
317   if( db->nExtension>0 ){
318     memcpy(aHandle, db->aExtension, sizeof(handle)*(db->nExtension-1));
319   }
320   sqliteFree(db->aExtension);
321   db->aExtension = aHandle;
322 
323   db->aExtension[db->nExtension-1] = handle;
324   return SQLITE_OK;
325 }
326 
327 /*
328 ** Call this routine when the database connection is closing in order
329 ** to clean up loaded extensions
330 */
331 void sqlite3CloseExtensions(sqlite3 *db){
332   int i;
333   for(i=0; i<db->nExtension; i++){
334     sqlite3OsDlclose(db->aExtension[i]);
335   }
336   sqliteFree(db->aExtension);
337 }
338 
339 /*
340 ** Enable or disable extension loading.  Extension loading is disabled by
341 ** default so as not to open security holes in older applications.
342 */
343 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){
344   if( onoff ){
345     db->flags |= SQLITE_LoadExtension;
346   }else{
347     db->flags &= ~SQLITE_LoadExtension;
348   }
349   return SQLITE_OK;
350 }
351 
352 /*
353 ** A list of automatically loaded extensions.
354 **
355 ** This list is shared across threads, so be sure to hold the
356 ** mutex while accessing or changing it.
357 */
358 static int nAutoExtension = 0;
359 static void **aAutoExtension = 0;
360 
361 
362 /*
363 ** Register a statically linked extension that is automatically
364 ** loaded by every new database connection.
365 */
366 int sqlite3_auto_extension(void *xInit){
367   int i;
368   int rc = SQLITE_OK;
369   sqlite3OsEnterMutex();
370   for(i=0; i<nAutoExtension; i++){
371     if( aAutoExtension[i]==xInit ) break;
372   }
373   if( i==nAutoExtension ){
374     nAutoExtension++;
375     aAutoExtension = sqlite3Realloc( aAutoExtension,
376                                      nAutoExtension*sizeof(aAutoExtension[0]) );
377     if( aAutoExtension==0 ){
378       nAutoExtension = 0;
379       rc = SQLITE_NOMEM;
380     }else{
381       aAutoExtension[nAutoExtension-1] = xInit;
382     }
383   }
384   sqlite3OsLeaveMutex();
385   assert( (rc&0xff)==rc );
386   return rc;
387 }
388 
389 /*
390 ** Reset the automatic extension loading mechanism.
391 */
392 void sqlite3_reset_auto_extension(void){
393   sqlite3OsEnterMutex();
394   sqliteFree(aAutoExtension);
395   aAutoExtension = 0;
396   nAutoExtension = 0;
397   sqlite3OsLeaveMutex();
398 }
399 
400 /*
401 ** Load all automatic extensions.
402 */
403 int sqlite3AutoLoadExtensions(sqlite3 *db){
404   int i;
405   int go = 1;
406   int rc = SQLITE_OK;
407   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);
408 
409   if( nAutoExtension==0 ){
410     /* Common case: early out without every having to acquire a mutex */
411     return SQLITE_OK;
412   }
413   for(i=0; go; i++){
414     char *zErrmsg = 0;
415     sqlite3OsEnterMutex();
416     if( i>=nAutoExtension ){
417       xInit = 0;
418       go = 0;
419     }else{
420       xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))
421               aAutoExtension[i];
422     }
423     sqlite3OsLeaveMutex();
424     if( xInit && xInit(db, &zErrmsg, &sqlite3_apis) ){
425       sqlite3Error(db, SQLITE_ERROR,
426             "automatic extension loading failed: %s", zErrmsg);
427       go = 0;
428       rc = SQLITE_ERROR;
429     }
430   }
431   return rc;
432 }
433 
434 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
435