/*

** 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.

*/

#ifndef SQLITE_OMIT_LOAD_EXTENSION

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

#include "sqlite3ext.h"

#include "sqliteInt.h"

#include "os.h"

#include <string.h>

#include <ctype.h>

/*

** 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

/*

** 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.

*/

const sqlite3_api_routines sqlite3_apis = {

  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,

};

/*

** 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 sqlite3_free().

*/

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 */

){

  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(zFile);

  if( handle==0 ){

    if( pzErrMsg ){

      *pzErrMsg = sqlite3_mprintf("unable to open shared library [%s]", zFile);

    }

    return SQLITE_ERROR;

  }

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

                   sqlite3OsDlsym(handle, zProc);

  if( xInit==0 ){

    if( pzErrMsg ){

       *pzErrMsg = sqlite3_mprintf("no entry point [%s] in shared library [%s]",

                                   zProc, zFile);

    }

    sqlite3OsDlclose(handle);

    return SQLITE_ERROR;

  }else if( xInit(db, &zErrmsg, &sqlite3_apis) ){

    if( pzErrMsg ){

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

    }

    sqlite3_free(zErrmsg);

    sqlite3OsDlclose(handle);

    return SQLITE_ERROR;

  }

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

  db->nExtension++;

  aHandle = sqliteMalloc(sizeof(handle)*db->nExtension);

  if( aHandle==0 ){

    return SQLITE_NOMEM;

  }

  if( db->nExtension>0 ){

    memcpy(aHandle, db->aExtension, sizeof(handle)*(db->nExtension-1));

  }

  sqliteFree(db->aExtension);

  db->aExtension = aHandle;

  db->aExtension[db->nExtension-1] = handle;

  return SQLITE_OK;

}

/*

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

** to clean up loaded extensions

*/

void sqlite3CloseExtensions(sqlite3 *db){

  int i;

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

    sqlite3OsDlclose(db->aExtension[i]);

  }

  sqliteFree(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){

  if( onoff ){

    db->flags |= SQLITE_LoadExtension;

  }else{

    db->flags &= ~SQLITE_LoadExtension;

  }

  return SQLITE_OK;

}

/*

** A list of automatically loaded extensions.

**

** This list is shared across threads, so be sure to hold the

** mutex while accessing or changing it.

*/

static int nAutoExtension = 0;

static void **aAutoExtension = 0;

/*

** Register a statically linked extension that is automatically

** loaded by every new database connection.

*/

int sqlite3_auto_extension(void *xInit){

  int i;

  int rc = SQLITE_OK;

  sqlite3OsEnterMutex();

  for(i=0; i<nAutoExtension; i++){

    if( aAutoExtension[i]==xInit ) break;

  }

  if( i==nAutoExtension ){

    nAutoExtension++;

    aAutoExtension = sqlite3Realloc( aAutoExtension,

                                     nAutoExtension*sizeof(aAutoExtension[0]) );

    if( aAutoExtension==0 ){

      nAutoExtension = 0;

      rc = SQLITE_NOMEM;

    }else{

      aAutoExtension[nAutoExtension-1] = xInit;

    }

  }

  sqlite3OsLeaveMutex();

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

  return rc;

}

/*

** Reset the automatic extension loading mechanism.

*/

void sqlite3_reset_auto_extension(void){

  sqlite3OsEnterMutex();

  sqliteFree(aAutoExtension);

  aAutoExtension = 0;

  nAutoExtension = 0;

  sqlite3OsLeaveMutex();

}

/*

** 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( nAutoExtension==0 ){

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

    return SQLITE_OK;

  }

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

    char *zErrmsg = 0;

    sqlite3OsEnterMutex();

    if( i>=nAutoExtension ){

      xInit = 0;

      go = 0;

    }else{

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

              aAutoExtension[i];

    }

    sqlite3OsLeaveMutex();

    if( xInit && xInit(db, &zErrmsg, &sqlite3_apis) ){

      sqlite3Error(db, SQLITE_ERROR,

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

      go = 0;

      rc = SQLITE_ERROR;

    }

  }

  return rc;

}

#endif /* SQLITE_OMIT_LOAD_EXTENSION */