/*

 ** 2006 June 7

 **

 ** The author disclaims copyright to this source code.  In place of

 ** a legal notice, here is a blessing:

 **

 **    May you do good and not evil.

 **    May you find forgiveness for yourself and forgive others.

 **    May you share freely, never taking more than you give.

 **

 *************************************************************************

 ** This file contains code used to dynamically load extensions into

 ** the SQLite library.

 **

 ** $Id: loadext.c,v 1.53 2008/08/02 03:50:39 drh Exp $

 */

 #ifndef SQLITE_CORE

   #define SQLITE_CORE 1  /* Disable the API redefinition in sqlite3ext.h */

 #endif

 #include "sqlite3ext.h"

 #include "sqliteInt.h"

 #include <string.h>

 #include <ctype.h>

 #ifndef SQLITE_OMIT_LOAD_EXTENSION

 /*

 ** Some API routines are omitted when various features are

 ** excluded from a build of SQLite.  Substitute a NULL pointer

 ** for any missing APIs.

 */

 #ifndef SQLITE_ENABLE_COLUMN_METADATA

 # define sqlite3_column_database_name   0

 # define sqlite3_column_database_name16 0

 # define sqlite3_column_table_name      0

 # define sqlite3_column_table_name16    0

 # define sqlite3_column_origin_name     0

 # define sqlite3_column_origin_name16   0

 # define sqlite3_table_column_metadata  0

 #endif

 #ifdef SQLITE_OMIT_AUTHORIZATION

 # define sqlite3_set_authorizer         0

 #endif

 #ifdef SQLITE_OMIT_UTF16

 # define sqlite3_bind_text16            0

 # define sqlite3_collation_needed16     0

 # define sqlite3_column_decltype16      0

 # define sqlite3_column_name16          0

 # define sqlite3_column_text16          0

 # define sqlite3_complete16             0

 # define sqlite3_create_collation16     0

 # define sqlite3_create_function16      0

 # define sqlite3_errmsg16               0

 # define sqlite3_open16                 0

 # define sqlite3_prepare16              0

 # define sqlite3_prepare16_v2           0

 # define sqlite3_result_error16         0

 # define sqlite3_result_text16          0

 # define sqlite3_result_text16be        0

 # define sqlite3_result_text16le        0

 # define sqlite3_value_text16           0

 # define sqlite3_value_text16be         0

 # define sqlite3_value_text16le         0

 # define sqlite3_column_database_name16 0

 # define sqlite3_column_table_name16    0

 # define sqlite3_column_origin_name16   0

 #endif

 #ifdef SQLITE_OMIT_COMPLETE

 # define sqlite3_complete 0

 # define sqlite3_complete16 0

 #endif

 #ifdef SQLITE_OMIT_PROGRESS_CALLBACK

 # define sqlite3_progress_handler 0

 #endif

 #ifdef SQLITE_OMIT_VIRTUALTABLE

 # define sqlite3_create_module 0

 # define sqlite3_create_module_v2 0

 # define sqlite3_declare_vtab 0

 #endif

 #ifdef SQLITE_OMIT_SHARED_CACHE

 # define sqlite3_enable_shared_cache 0

 #endif

 #ifdef SQLITE_OMIT_TRACE

 # define sqlite3_profile       0

 # define sqlite3_trace         0

 #endif

 #ifdef SQLITE_OMIT_GET_TABLE

 # define sqlite3_free_table    0

 # define sqlite3_get_table     0

 #endif

 #ifdef SQLITE_OMIT_INCRBLOB

 #define sqlite3_bind_zeroblob  0

 #define sqlite3_blob_bytes     0

 #define sqlite3_blob_close     0

 #define sqlite3_blob_open      0

 #define sqlite3_blob_read      0

 #define sqlite3_blob_write     0

 #endif

 /*

 ** The following structure contains pointers to all SQLite API routines.

 ** A pointer to this structure is passed into extensions when they are

 ** loaded so that the extension can make calls back into the SQLite

 ** library.

 **

 ** When adding new APIs, add them to the bottom of this structure

 ** in order to preserve backwards compatibility.

 **

 ** Extensions that use newer APIs should first call the

 ** sqlite3_libversion_number() to make sure that the API they

 ** intend to use is supported by the library.  Extensions should

 ** also check to make sure that the pointer to the function is

 ** not NULL before calling it.

 */

 static const sqlite3_api_routines sqlite3Apis = {

   sqlite3_aggregate_context,

   sqlite3_aggregate_count,

   sqlite3_bind_blob,

   sqlite3_bind_double,

   sqlite3_bind_int,

   sqlite3_bind_int64,

   sqlite3_bind_null,

   sqlite3_bind_parameter_count,

   sqlite3_bind_parameter_index,

   sqlite3_bind_parameter_name,

   sqlite3_bind_text,

   sqlite3_bind_text16,

   sqlite3_bind_value,

   sqlite3_busy_handler,

   sqlite3_busy_timeout,

   sqlite3_changes,

   sqlite3_close,

   sqlite3_collation_needed,

   sqlite3_collation_needed16,

   sqlite3_column_blob,

   sqlite3_column_bytes,

   sqlite3_column_bytes16,

   sqlite3_column_count,

   sqlite3_column_database_name,

   sqlite3_column_database_name16,

   sqlite3_column_decltype,

   sqlite3_column_decltype16,

   sqlite3_column_double,

   sqlite3_column_int,

   sqlite3_column_int64,

   sqlite3_column_name,

   sqlite3_column_name16,

   sqlite3_column_origin_name,

   sqlite3_column_origin_name16,

   sqlite3_column_table_name,

   sqlite3_column_table_name16,

   sqlite3_column_text,

   sqlite3_column_text16,

   sqlite3_column_type,

   sqlite3_column_value,

   sqlite3_commit_hook,

   sqlite3_complete,

   sqlite3_complete16,

   sqlite3_create_collation,

   sqlite3_create_collation16,

   sqlite3_create_function,

   sqlite3_create_function16,

   sqlite3_create_module,

   sqlite3_data_count,

   sqlite3_db_handle,

   sqlite3_declare_vtab,

   sqlite3_enable_shared_cache,

   sqlite3_errcode,

   sqlite3_errmsg,

   sqlite3_errmsg16,

   sqlite3_exec,

   sqlite3_expired,

   sqlite3_finalize,

   sqlite3_free,

   sqlite3_free_table,

   sqlite3_get_autocommit,

   sqlite3_get_auxdata,

   sqlite3_get_table,

   0,     /* Was sqlite3_global_recover(), but that function is deprecated */

   sqlite3_interrupt,

   sqlite3_last_insert_rowid,

   sqlite3_libversion,

   sqlite3_libversion_number,

   sqlite3_malloc,

   sqlite3_mprintf,

   sqlite3_open,

   sqlite3_open16,

   sqlite3_prepare,

   sqlite3_prepare16,

   sqlite3_profile,

   sqlite3_progress_handler,

   sqlite3_realloc,

   sqlite3_reset,

   sqlite3_result_blob,

   sqlite3_result_double,

   sqlite3_result_error,

   sqlite3_result_error16,

   sqlite3_result_int,

   sqlite3_result_int64,

   sqlite3_result_null,

   sqlite3_result_text,

   sqlite3_result_text16,

   sqlite3_result_text16be,

   sqlite3_result_text16le,

   sqlite3_result_value,

   sqlite3_rollback_hook,

   sqlite3_set_authorizer,

   sqlite3_set_auxdata,

   sqlite3_snprintf,

   sqlite3_step,

   sqlite3_table_column_metadata,

   sqlite3_thread_cleanup,

   sqlite3_total_changes,

   sqlite3_trace,

   sqlite3_transfer_bindings,

   sqlite3_update_hook,

   sqlite3_user_data,

   sqlite3_value_blob,

   sqlite3_value_bytes,

   sqlite3_value_bytes16,

   sqlite3_value_double,

   sqlite3_value_int,

   sqlite3_value_int64,

   sqlite3_value_numeric_type,

   sqlite3_value_text,

   sqlite3_value_text16,

   sqlite3_value_text16be,

   sqlite3_value_text16le,

   sqlite3_value_type,

   sqlite3_vmprintf,

   /*

   ** The original API set ends here.  All extensions can call any

   ** of the APIs above provided that the pointer is not NULL.  But

   ** before calling APIs that follow, extension should check the

   ** sqlite3_libversion_number() to make sure they are dealing with

   ** a library that is new enough to support that API.

   *************************************************************************

   */

   sqlite3_overload_function,

   /*

   ** Added after 3.3.13

   */

   sqlite3_prepare_v2,

   sqlite3_prepare16_v2,

   sqlite3_clear_bindings,

   /*

   ** Added for 3.4.1

   */

   sqlite3_create_module_v2,

   /*

   ** Added for 3.5.0

   */

   sqlite3_bind_zeroblob,

   sqlite3_blob_bytes,

   sqlite3_blob_close,

   sqlite3_blob_open,

   sqlite3_blob_read,

   sqlite3_blob_write,

   sqlite3_create_collation_v2,

   sqlite3_file_control,

   sqlite3_memory_highwater,

   sqlite3_memory_used,

 #ifdef SQLITE_MUTEX_NOOP

   0, 

   0, 

   0,

   0,

   0,

 #else

   sqlite3_mutex_alloc,

   sqlite3_mutex_enter,

   sqlite3_mutex_free,

   sqlite3_mutex_leave,

   sqlite3_mutex_try,

 #endif

   sqlite3_open_v2,

   sqlite3_release_memory,

   sqlite3_result_error_nomem,

   sqlite3_result_error_toobig,

   sqlite3_sleep,

   sqlite3_soft_heap_limit,

   sqlite3_vfs_find,

   sqlite3_vfs_register,

   sqlite3_vfs_unregister,

   /*

   ** Added for 3.5.8

   */

   sqlite3_threadsafe,

   sqlite3_result_zeroblob,

   sqlite3_result_error_code,

   sqlite3_test_control,

   sqlite3_randomness,

   sqlite3_context_db_handle,

   /*

   ** Added for 3.6.0

   */

   sqlite3_extended_result_codes,

   sqlite3_limit,

   sqlite3_next_stmt,

   sqlite3_sql,

   sqlite3_status,

 };

 /*

 ** Attempt to load an SQLite extension library contained in the file

 ** zFile.  The entry point is zProc.  zProc may be 0 in which case a

 ** default entry point name (sqlite3_extension_init) is used.  Use

 ** of the default name is recommended.

 **

 ** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.

 **

 ** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with 

 ** error message text.  The calling function should free this memory

 ** by calling sqlite3DbFree(db, ).

 */

 static int sqlite3LoadExtension(

   sqlite3 *db,          /* Load the extension into this database connection */

   const char *zFile,    /* Name of the shared library containing extension */

   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */

   char **pzErrMsg       /* Put error message here if not 0 */

 ){

   sqlite3_vfs *pVfs = db->pVfs;

   void *handle;

   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);

   char *zErrmsg = 0;

   void **aHandle;

   /* Ticket #1863.  To avoid a creating security problems for older

   ** applications that relink against newer versions of SQLite, the

   ** ability to run load_extension is turned off by default.  One

   ** must call sqlite3_enable_load_extension() to turn on extension

   ** loading.  Otherwise you get the following error.

   */

   if( (db->flags & SQLITE_LoadExtension)==0 ){

     if( pzErrMsg ){

       *pzErrMsg = sqlite3_mprintf("not authorized");

     }

     return SQLITE_ERROR;

   }

   if( zProc==0 ){

     zProc = "sqlite3_extension_init";

   }

   handle = sqlite3OsDlOpen(pVfs, zFile);

   if( handle==0 ){

     if( pzErrMsg ){

       char zErr[256];

       zErr[sizeof(zErr)-1] = '\0';

       sqlite3_snprintf(sizeof(zErr)-1, zErr, 

           "unable to open shared library [%s]", zFile);

       sqlite3OsDlError(pVfs, sizeof(zErr)-1, zErr);

       *pzErrMsg = sqlite3DbStrDup(0, zErr);

     }

     return SQLITE_ERROR;

   }

   xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))

                    sqlite3OsDlSym(pVfs, handle, zProc);

   if( xInit==0 ){

     if( pzErrMsg ){

       char zErr[256];

       zErr[sizeof(zErr)-1] = '\0';

       sqlite3_snprintf(sizeof(zErr)-1, zErr,

           "no entry point [%s] in shared library [%s]", zProc,zFile);

       sqlite3OsDlError(pVfs, sizeof(zErr)-1, zErr);

       *pzErrMsg = sqlite3DbStrDup(0, zErr);

       sqlite3OsDlClose(pVfs, handle);

     }

     return SQLITE_ERROR;

   }else if( xInit(db, &zErrmsg, &sqlite3Apis) ){

     if( pzErrMsg ){

       *pzErrMsg = sqlite3_mprintf("error during initialization: %s", zErrmsg);

     }

     sqlite3_free(zErrmsg);

     sqlite3OsDlClose(pVfs, handle);

     return SQLITE_ERROR;

   }

   /* Append the new shared library handle to the db->aExtension array. */

   aHandle = sqlite3DbMallocZero(db, sizeof(handle)*(db->nExtension+1));

   if( aHandle==0 ){

     return SQLITE_NOMEM;

   }

   if( db->nExtension>0 ){

     memcpy(aHandle, db->aExtension, sizeof(handle)*db->nExtension);

   }

   sqlite3DbFree(db, db->aExtension);

   db->aExtension = aHandle;

   db->aExtension[db->nExtension++] = handle;

   return SQLITE_OK;

 }

 int sqlite3_load_extension(

   sqlite3 *db,          /* Load the extension into this database connection */

   const char *zFile,    /* Name of the shared library containing extension */

   const char *zProc,    /* Entry point.  Use "sqlite3_extension_init" if 0 */

   char **pzErrMsg       /* Put error message here if not 0 */

 ){

   int rc;

   sqlite3_mutex_enter(db->mutex);

   rc = sqlite3LoadExtension(db, zFile, zProc, pzErrMsg);

   sqlite3_mutex_leave(db->mutex);

   return rc;

 }

 /*

 ** Call this routine when the database connection is closing in order

 ** to clean up loaded extensions

 */

 void sqlite3CloseExtensions(sqlite3 *db){

   int i;

   assert( sqlite3_mutex_held(db->mutex) );

   for(i=0; i<db->nExtension; i++){

     sqlite3OsDlClose(db->pVfs, db->aExtension[i]);

   }

   sqlite3DbFree(db, db->aExtension);

 }

 /*

 ** Enable or disable extension loading.  Extension loading is disabled by

 ** default so as not to open security holes in older applications.

 */

 int sqlite3_enable_load_extension(sqlite3 *db, int onoff){

   sqlite3_mutex_enter(db->mutex);

   if( onoff ){

     db->flags |= SQLITE_LoadExtension;

   }else{

     db->flags &= ~SQLITE_LoadExtension;

   }

   sqlite3_mutex_leave(db->mutex);

   return SQLITE_OK;

 }

 #endif /* SQLITE_OMIT_LOAD_EXTENSION */

 /*

 ** The auto-extension code added regardless of whether or not extension

 ** loading is supported.  We need a dummy sqlite3Apis pointer for that

 ** code if regular extension loading is not available.  This is that

 ** dummy pointer.

 */

 #ifdef SQLITE_OMIT_LOAD_EXTENSION

 static const sqlite3_api_routines sqlite3Apis = { 0 };

 #endif

 /*

 ** The following object holds the list of automatically loaded

 ** extensions.

 **

 ** This list is shared across threads.  The SQLITE_MUTEX_STATIC_MASTER

 ** mutex must be held while accessing this list.

 */

 static struct {

   int nExt;        /* Number of entries in aExt[] */          

   void **aExt;     /* Pointers to the extension init functions */

 } autoext = { 0, 0 };

 /*

 ** Register a statically linked extension that is automatically

 ** loaded by every new database connection.

 */

 int sqlite3_auto_extension(void *xInit){

   int rc = SQLITE_OK;

 #ifndef SQLITE_OMIT_AUTOINIT

   rc = sqlite3_initialize();

   if( rc ){

     return rc;

   }else

 #endif

   {

     int i;

 #ifndef SQLITE_MUTEX_NOOP

     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);

 #endif

     sqlite3_mutex_enter(mutex);

     for(i=0; i<autoext.nExt; i++){

       if( autoext.aExt[i]==xInit ) break;

     }

     if( i==autoext.nExt ){

       int nByte = (autoext.nExt+1)*sizeof(autoext.aExt[0]);

       void **aNew;

       aNew = sqlite3_realloc(autoext.aExt, nByte);

       if( aNew==0 ){

         rc = SQLITE_NOMEM;

       }else{

         autoext.aExt = aNew;

         autoext.aExt[autoext.nExt] = xInit;

         autoext.nExt++;

       }

     }

     sqlite3_mutex_leave(mutex);

     assert( (rc&0xff)==rc );

     return rc;

   }

 }

 /*

 ** Reset the automatic extension loading mechanism.

 */

 void sqlite3_reset_auto_extension(void){

 #ifndef SQLITE_OMIT_AUTOINIT

   if( sqlite3_initialize()==SQLITE_OK )

 #endif

   {

 #ifndef SQLITE_MUTEX_NOOP

     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);

 #endif

     sqlite3_mutex_enter(mutex);

     sqlite3_free(autoext.aExt);

     autoext.aExt = 0;

     autoext.nExt = 0;

     sqlite3_mutex_leave(mutex);

   }

 }

 /*

 ** Load all automatic extensions.

 */

 int sqlite3AutoLoadExtensions(sqlite3 *db){

   int i;

   int go = 1;

   int rc = SQLITE_OK;

   int (*xInit)(sqlite3*,char**,const sqlite3_api_routines*);

   if( autoext.nExt==0 ){

     /* Common case: early out without every having to acquire a mutex */

     return SQLITE_OK;

   }

   for(i=0; go; i++){

     char *zErrmsg = 0;

 #ifndef SQLITE_MUTEX_NOOP

     sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);

 #endif

     sqlite3_mutex_enter(mutex);

     if( i>=autoext.nExt ){

       xInit = 0;

       go = 0;

     }else{

       xInit = (int(*)(sqlite3*,char**,const sqlite3_api_routines*))

               autoext.aExt[i];

     }

     sqlite3_mutex_leave(mutex);

     if( xInit && xInit(db, &zErrmsg, &sqlite3Apis) ){

       sqlite3Error(db, SQLITE_ERROR,

             "automatic extension loading failed: %s", zErrmsg);

       go = 0;

       rc = SQLITE_ERROR;

       sqlite3_free(zErrmsg);

     }

   }

   return rc;

 }