SQLite

**
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** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.763 2008/07/23 21:07:25 drh Exp $
** $Id: vdbe.c,v 1.764 2008/07/26 18:26:10 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor

    /* Make sure K is a string and make zKey point to K
    */
    assert( pK->flags & MEM_Blob );
    zKey = pK->z;
    nKey = pK->n;

    szRowid = sqlite3VdbeIdxRowidLen((u8*)zKey);
    rc = sqlite3VdbeIdxRowidLen((u8*)zKey, nKey, &szRowid);
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }
    len = nKey-szRowid;

    /* Search for an entry in P1 where all but the last four bytes match K.
    ** If there is no such entry, jump immediately to P2.
    */
    assert( pCx->deferredMoveto==0 );
    pCx->cacheStatus = CACHE_STALE;

*************************************************************************
** This is the header file for information that is private to the
** VDBE.  This information used to all be at the top of the single
** source code file "vdbe.c".  When that file became too big (over
** 6000 lines long) it was split up into several smaller files and
** this header information was factored out.
**
** $Id: vdbeInt.h,v 1.149 2008/06/25 00:12:41 drh Exp $
** $Id: vdbeInt.h,v 1.150 2008/07/26 18:26:10 danielk1977 Exp $
*/
#ifndef _VDBEINT_H_
#define _VDBEINT_H_

/*
** intToKey() and keyToInt() used to transform the rowid.  But with
** the latest versions of the design they are no-ops.

int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);

int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord *,int,const unsigned char*,int*);
int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
int sqlite3VdbeIdxRowidLen(const u8*);
int sqlite3VdbeIdxRowidLen(const u8*, int, int*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeHalt(Vdbe*);
int sqlite3VdbeChangeEncoding(Mem *, int);
int sqlite3VdbeMemTooBig(Mem*);
int sqlite3VdbeMemCopy(Mem*, const Mem*);
void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.399 2008/07/22 05:18:01 shane Exp $
** $Id: vdbeaux.c,v 1.400 2008/07/26 18:26:10 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The argument is an index entry composed using the OP_MakeRecord opcode.
** The last entry in this record should be an integer (specifically
** an integer rowid).  This routine returns the number of bytes in
** that integer.
*/
int sqlite3VdbeIdxRowidLen(const u8 *aKey){
int sqlite3VdbeIdxRowidLen(const u8 *aKey, int nKey, int *pRowidLen){
  u32 szHdr;        /* Size of the header */
  u32 typeRowid;    /* Serial type of the rowid */

  (void)getVarint32(aKey, szHdr);
  if( szHdr>nKey ){
    return SQLITE_CORRUPT_BKPT;
  }
  (void)getVarint32(&aKey[szHdr-1], typeRowid);
  return sqlite3VdbeSerialTypeLen(typeRowid);
  *pRowidLen = sqlite3VdbeSerialTypeLen(typeRowid);
  return SQLITE_OK;
}
  

/*
** pCur points at an index entry created using the OP_MakeRecord opcode.
** Read the rowid (the last field in the record) and store it in *rowid.
** Return SQLITE_OK if everything works, or an error code otherwise.

  if( nCellKey<=0 ){
    *res = 0;
    return SQLITE_OK;
  }
  m.db = 0;
  m.flags = 0;
  m.zMalloc = 0;
  rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, nCellKey, 1, &m);
  if( rc ){
  if( (rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, nCellKey, 1, &m))
   || (rc = sqlite3VdbeIdxRowidLen((u8*)m.z, m.n, &lenRowid))
  ){
    return rc;
  }
  lenRowid = sqlite3VdbeIdxRowidLen((u8*)m.z);
  if( !pUnpacked ){
    pRec = sqlite3VdbeRecordUnpack(pC->pKeyInfo, nKey, pKey,
                                zSpace, sizeof(zSpace));
  }else{
    pRec = pUnpacked;
  }
  if( pRec==0 ){

#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests to make sure SQLite does not crash or
# segfault if it sees a corrupt database file.  It specifically focuses
# on corrupt cell offsets in a btree page.
#
# $Id: corrupt7.test,v 1.3 2008/07/25 14:53:17 drh Exp $
# $Id: corrupt7.test,v 1.4 2008/07/26 18:26:10 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# We must have the page_size pragma for these tests to work.
#
ifcapable !pager_pragmas {

  db close
  hexio_write test.db 1062 04
  sqlite3 db test.db
  db eval {PRAGMA integrity_check(1)}
} {{*** in database main ***
Corruption detected in cell 15 on page 2}}

do_test corrupt7-3.1 {
  execsql {
    DROP TABLE t1;
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 'one');
    INSERT INTO t1 VALUES(100, 'one hundred');
    INSERT INTO t1 VALUES(100000, 'one hundred thousand');
    CREATE INDEX i1 ON t1(b);
  }
  db close

  # Locate the 3rd cell in the index.
  set cell_offset [hexio_get_int [hexio_read test.db [expr 1024*2 + 12] 2]]
  incr cell_offset [expr 1024*2]
  incr cell_offset 1

  # This write corrupts the "header-size" field of the database record
  # stored in the index cell. At one point this was causing sqlite to 
  # reference invalid memory.
  hexio_write test.db $cell_offset FFFF7F
  
  sqlite3 db test.db
  catchsql {
    SELECT b FROM t1 WHERE b > 'o' AND b < 'p';
  }
} {1 {database disk image is malformed}}

finish_test