SQLite

  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3 *db;
  const char *zSql;
  char *zCopy = 0;                /* malloc() copy of zSql */
  int bytes;
  const char *zTail = 0;
  sqlite3_stmt *pStmt = 0;
  char zBuf[50];
  int rc;

  if( objc!=5 && objc!=4 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " DB sql bytes tailvar", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zSql = Tcl_GetString(objv[2]);
  if( Tcl_GetIntFromObj(interp, objv[3], &bytes) ) return TCL_ERROR;

  /* Instead of using zSql directly, make a copy into a buffer obtained
  ** directly from malloc(). The idea is to make it easier for valgrind
  ** to spot buffer overreads.  */
  if( bytes>=0 ){
    zCopy = malloc(bytes);
    memcpy(zCopy, zSql, bytes);
  }else{
    int n = strlen(zSql) + 1;
    zCopy = malloc(n);
    memcpy(zCopy, zSql, n);
  }
  rc = sqlite3_prepare_v2(db, zCopy, bytes, &pStmt, objc>=5 ? &zTail : 0);
  free(zCopy);
  zTail = &zSql[(zTail - zCopy)];

  assert(rc==SQLITE_OK || pStmt==0);
  Tcl_ResetResult(interp);
  if( sqlite3TestErrCode(interp, db, rc) ) return TCL_ERROR;
  if( zTail && objc>=5 ){
    if( bytes>=0 ){
      bytes = bytes - (int)(zTail-zSql);
    }

  assert( iDb>=0 );

  pTable->tabFlags |= TF_Virtual;
  pTable->nModuleArg = 0;
  addModuleArgument(db, pTable, sqlite3NameFromToken(db, pModuleName));
  addModuleArgument(db, pTable, 0);
  addModuleArgument(db, pTable, sqlite3DbStrDup(db, pTable->zName));
  assert( (pParse->sNameToken.z==pName2->z && pName2->z!=0)
       || (pParse->sNameToken.z==pName1->z && pName2->z==0)
  );
  pParse->sNameToken.n = (int)(
      &pModuleName->z[pModuleName->n] - pParse->sNameToken.z
  );

#ifndef SQLITE_OMIT_AUTHORIZATION
  /* Creating a virtual table invokes the authorization callback twice.
  ** The first invocation, to obtain permission to INSERT a row into the
  ** sqlite_master table, has already been made by sqlite3StartTable().
  ** The second call, to obtain permission to create the table, is made now.
  */

do_execsql_test 21.2 {
  SELECT * FROM t9v WHERE a<b;
} {1 2 3}

do_execsql_test 21.3 {
  SELECT * FROM t9v WHERE a=b;
} {2 2 2}

#-------------------------------------------------------------------------
# At one point executing a CREATE VIRTUAL TABLE statement that specified 
# a database name but no virtual table arguments was causing an internal
# buffer overread. Valgrind would report errors while running the following 
# tests. Specifically:
#
#   CREATE VIRTUAL TABLE t1 USING fts4;          -- Ok - no db name.
#   CREATE VIRTUAL TABLE main.t1 USING fts4(x);  -- Ok - has vtab arguments.
#   CREATE VIRTUAL TABLE main.t1 USING fts4;     -- Had the problem. 
#
ifcapable fts3 {
  forcedelete test.db2
  set nm [string repeat abcdefghij 100]
  do_execsql_test 22.1 {
    ATTACH 'test.db2' AS $nm
  }
  
  execsql "SELECT * FROM sqlite_master"
  do_execsql_test 22.2 "CREATE VIRTUAL TABLE ${nm}.t1 USING fts4"
  
  do_test 22.3.1 {
    set sql "CREATE VIRTUAL TABLE ${nm}.t2 USING fts4"
    set stmt [sqlite3_prepare_v2 db $sql -1 dummy]
    sqlite3_step $stmt
  } {SQLITE_DONE}
  
  do_test 22.3.2 {
    sqlite3_finalize $stmt
  } {SQLITE_OK}
  
  do_test 22.4.1 {
    set sql "CREATE VIRTUAL TABLE ${nm}.t3 USING fts4"
    set n [string length $sql]
    set stmt [sqlite3_prepare db "${sql}xyz" $n dummy]
    sqlite3_step $stmt
  } {SQLITE_DONE}
  
  do_test 22.4.2 {
    sqlite3_finalize $stmt
  } {SQLITE_OK}
}

finish_test