return id->pMethods->xBreakLock(id);
}
int sqlite3OsCheckReservedLock(sqlite3_file *id){
  return id->pMethods->xCheckReservedLock(id);
}
int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE;
}
int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}

#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
  /* These methods are currently only used for testing and debugging. */
................................................................................
int sqlite3OsOpen(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  sqlite3_file *pFile, 
  int flags, 
  int *pFlagsOut
){



  return pVfs->xOpen(pVfs->pAppData, zPath, pFile, flags, pFlagsOut);
}
int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  return pVfs->xDelete(pVfs->pAppData, zPath, dirSync);
}
int sqlite3OsAccess(sqlite3_vfs *pVfs, const char *zPath, int flags){
  return pVfs->xAccess(pVfs->pAppData, zPath, flags);
................................................................................
  return pVfs->xCurrentTime(pVfs->pAppData, pTimeOut);
}

int sqlite3OsOpenMalloc(
  sqlite3_vfs *pVfs, 
  const char *zFile, 
  sqlite3_file **ppFile, 
  int flags

){
  int rc = SQLITE_NOMEM;
  sqlite3_file *pFile;
  pFile = (sqlite3_file *)sqlite3_malloc(pVfs->szOsFile);
  if( pFile ){
    rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, 0);
    if( rc!=SQLITE_OK ){
      sqlite3_free(pFile);
    }else{
      *ppFile = pFile;
    }
  }
  return rc;

  return id->pMethods->xBreakLock(id);
}
int sqlite3OsCheckReservedLock(sqlite3_file *id){
  return id->pMethods->xCheckReservedLock(id);
}
int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}

#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
  /* These methods are currently only used for testing and debugging. */
................................................................................
int sqlite3OsOpen(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  sqlite3_file *pFile, 
  int flags, 
  int *pFlagsOut
){
#if defined(SQLITE_TEST) && !defined(SQLITE_OMIT_DISKIO)
  return sqlite3CrashFileOpen(pVfs, zPath, pFile, flags, pFlagsOut);
#endif
  return pVfs->xOpen(pVfs->pAppData, zPath, pFile, flags, pFlagsOut);
}
int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  return pVfs->xDelete(pVfs->pAppData, zPath, dirSync);
}
int sqlite3OsAccess(sqlite3_vfs *pVfs, const char *zPath, int flags){
  return pVfs->xAccess(pVfs->pAppData, zPath, flags);
................................................................................
  return pVfs->xCurrentTime(pVfs->pAppData, pTimeOut);
}

int sqlite3OsOpenMalloc(
  sqlite3_vfs *pVfs, 
  const char *zFile, 
  sqlite3_file **ppFile, 
  int flags,
  int *pOutFlags
){
  int rc = SQLITE_NOMEM;
  sqlite3_file *pFile;
  pFile = (sqlite3_file *)sqlite3_malloc(pVfs->szOsFile);
  if( pFile ){
    rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
    if( rc!=SQLITE_OK ){
      sqlite3_free(pFile);
    }else{
      *ppFile = pFile;
    }
  }
  return rc;

int sqlite3OsSleep(sqlite3_vfs *, int);
int sqlite3OsCurrentTime(sqlite3_vfs *, double*);

/*
** Convenience functions for opening and closing files using 
** sqlite3_malloc() to obtain space for the file-handle structure.
*/
int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int); 
int sqlite3OsCloseFree(sqlite3_file *);

#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
  int sqlite3OsFileHandle(sqlite3_file *id);
  int sqlite3OsLockState(sqlite3_file *id);
#endif

#endif /* _SQLITE_OS_H_ */

int sqlite3OsSleep(sqlite3_vfs *, int);
int sqlite3OsCurrentTime(sqlite3_vfs *, double*);

/*
** Convenience functions for opening and closing files using 
** sqlite3_malloc() to obtain space for the file-handle structure.
*/
int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int,int*);
int sqlite3OsCloseFree(sqlite3_file *);

#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
  int sqlite3OsFileHandle(sqlite3_file *id);
  int sqlite3OsLockState(sqlite3_file *id);
#endif

#endif /* _SQLITE_OS_H_ */

/*
** The unixFile structure is subclass of sqlite3_file specific for the unix
** protability layer.
*/
typedef struct unixFile unixFile;
struct unixFile {
  sqlite3_io_methods const *pMethod;  /* Always the first entry */






  struct openCnt *pOpen;    /* Info about all open fd's on this inode */
  struct lockInfo *pLock;   /* Info about locks on this inode */
#ifdef SQLITE_ENABLE_LOCKING_STYLE
  void *lockingContext;     /* Locking style specific state */
#endif /* SQLITE_ENABLE_LOCKING_STYLE */
  int h;                    /* The file descriptor */
  unsigned char locktype;   /* The type of lock held on this fd */
  unsigned char isOpen;     /* True if needs to be closed */
  int dirfd;                /* File descriptor for the directory */
  i64 offset;               /* Seek offset */
#ifdef SQLITE_UNIX_THREADS
  pthread_t tid;            /* The thread that "owns" this unixFile */
#endif
};


/*
** Provide the ability to override some OS-layer functions during
** testing.  This is used to simulate OS crashes to verify that 
** commits are atomic even in the event of an OS crash.
*/
#ifdef SQLITE_CRASH_TEST
  extern int sqlite3CrashTestEnable;
  int sqlite3CrashFileWrap(sqlite3_file *, const char *, sqlite3_file **);
  static int CRASH_TEST_OVERRIDE(const char *zFile, sqlite3_file **pId, int rc){
    if( rc==SQLITE_OK && sqlite3CrashTestEnable ){
      rc = sqlite3CrashFileWrap(*pId, zFile, pId); 
    }
    return rc;
  }
#else
# define CRASH_TEST_OVERRIDE(A,B,C) C
#endif


/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"

/*
................................................................................
  SimulateIOError( newOffset-- );
  if( newOffset!=offset ){
    return -1;
  }
  got = read(id->h, pBuf, cnt);
#endif
  TIMER_END;
  OSTRACE5("READ    %-3d %5d %7lld %d\n", id->h, got, id->offset, TIMER_ELAPSED);
  return got;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.

/*
** The unixFile structure is subclass of sqlite3_file specific for the unix
** protability layer.
*/
typedef struct unixFile unixFile;
struct unixFile {
  sqlite3_io_methods const *pMethod;  /* Always the first entry */
#ifdef SQLITE_TEST
  /* In test mode, increase the size of this structure a bit so that 
  ** it is larger than the struct CrashFile defined in test6.c.
  */
  char aPadding[32];
#endif
  struct openCnt *pOpen;    /* Info about all open fd's on this inode */
  struct lockInfo *pLock;   /* Info about locks on this inode */
#ifdef SQLITE_ENABLE_LOCKING_STYLE
  void *lockingContext;     /* Locking style specific state */
#endif /* SQLITE_ENABLE_LOCKING_STYLE */
  int h;                    /* The file descriptor */
  unsigned char locktype;   /* The type of lock held on this fd */
  unsigned char isOpen;     /* True if needs to be closed */
  int dirfd;                /* File descriptor for the directory */

#ifdef SQLITE_UNIX_THREADS
  pthread_t tid;            /* The thread that "owns" this unixFile */
#endif
};





















/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"

/*
................................................................................
  SimulateIOError( newOffset-- );
  if( newOffset!=offset ){
    return -1;
  }
  got = read(id->h, pBuf, cnt);
#endif
  TIMER_END;
  OSTRACE5("READ    %-3d %5d %7lld %d\n", id->h, got, offset, TIMER_ELAPSED);
  return got;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.591 2007/08/17 15:53:37 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_
#include "sqliteLimit.h"


#if defined(SQLITE_TCL) || defined(TCLSH)
................................................................................
int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
int sqlite3VtabBegin(sqlite3 *, sqlite3_vtab *);
FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, int, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);


#if SQLITE_MAX_EXPR_DEPTH>0
  void sqlite3ExprSetHeight(Expr *);
  int sqlite3SelectExprHeight(Select *);
#else
  #define sqlite3ExprSetHeight(x)
#endif

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.592 2007/08/20 14:23:44 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_
#include "sqliteLimit.h"


#if defined(SQLITE_TCL) || defined(TCLSH)
................................................................................
int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
int sqlite3VtabBegin(sqlite3 *, sqlite3_vtab *);
FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, int, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite3CrashFileOpen(sqlite3_vfs*, const char*, sqlite3_file*, int,int*);

#if SQLITE_MAX_EXPR_DEPTH>0
  void sqlite3ExprSetHeight(Expr *);
  int sqlite3SelectExprHeight(Select *);
#else
  #define sqlite3ExprSetHeight(x)
#endif

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.47 2007/08/18 10:59:21 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;

  pVfs = sqlite3_find_vfs(0);
  rc = sqlite3OsOpenMalloc(pVfs, argv[2], &fd, 
      (SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB)
  );
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the pager.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test2.c,v 1.48 2007/08/20 14:23:44 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;

  pVfs = sqlite3_find_vfs(0);
  rc = sqlite3OsOpenMalloc(pVfs, argv[2], &fd, 
      (SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB), 0
  );
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;

  WriteBuffer *pNext;          /* Next in CrashGlobal.pWriteList */
};

struct CrashFile {
  const sqlite3_io_methods *pMethod;   /* Must be first */
  sqlite3_file *pRealFile;             /* Underlying "real" file handle */
  char *zName;





};

struct CrashGlobal {
  WriteBuffer *pWriteList;     /* Head of write-list */


  int iSectorSize;             /* Value of simulated sector size */
  int iDeviceCharacteristics;  /* Value of simulated device characteristics */

  int iCrash;                  /* Crash on the iCrash'th call to xSync() */
  char zCrashFile[500];        /* Crash during an xSync() on this file */ 
};

static CrashGlobal g = {0, SQLITE_DEFAULT_SECTOR_SIZE, 0, 0};

/*
** Set this global variable to 1 to enable crash testing.
*/
int sqlite3CrashTestEnable = 0;

/*
** Flush the write-list as if xSync() had been called on file handle
** pFile. If isCrash is true, simulate a crash.
*/
static int writeListSync(CrashFile *pFile, int isCrash){
  int rc = SQLITE_OK;
  int iDc = g.iDeviceCharacteristics;


  WriteBuffer *pWrite;
  WriteBuffer **ppPtr;

  /* Set pFinal to point to the last element of the write-list that
  ** is associated with file handle pFile.
  */
................................................................................
    for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext){
      if( pWrite->pFile==pFile ){
        pFinal = pWrite;
      }
    }
  }



  ppPtr = &g.pWriteList;
  for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){


    /* (eAction==1)      -> write block out normally,
    ** (eAction==2)      -> do nothing,
    ** (eAction==3)      -> trash sectors.
    */
    int eAction = 0;
    if( !isCrash ){
................................................................................
      }
    }

    switch( eAction ){
      case 1: {               /* Write out correctly */
        if( pWrite->zBuf ){
          rc = sqlite3OsWrite(
              pFile->pRealFile, pWrite->zBuf, pWrite->nBuf, pWrite->iOffset
          );
        }else{
          rc = sqlite3OsTruncate(pFile->pRealFile, pWrite->iOffset);
        }
        *ppPtr = pWrite->pNext;
        sqlite3_free(pWrite);
        break;
      }
      case 2: {               /* Do nothing */
        ppPtr = &pWrite->pNext;
        break;
      }
      case 3: {               /* Trash sectors */
        u8 *zGarbage;
        sqlite3_int64 iFirst = (pWrite->iOffset%g.iSectorSize);
        sqlite3_int64 iLast = (pWrite->iOffset+pWrite->nBuf-1)%g.iSectorSize;



        zGarbage = sqlite3_malloc(g.iSectorSize);
        if( zGarbage ){
          sqlite3_int64 i;
          for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
            sqlite3Randomness(g.iSectorSize, zGarbage); 
            rc = sqlite3OsWrite(
              pFile->pRealFile, zGarbage, g.iSectorSize, i*g.iSectorSize
            );
          }
          sqlite3_free(zGarbage);
        }else{
          rc = SQLITE_NOMEM;
        }

................................................................................

    if( pWrite==pFinal ) break;
  }

  if( rc==SQLITE_OK && isCrash ){
    exit(-1);
  }




  return rc;
}

/*
** Add an entry to the end of the write-list.
*/
................................................................................
  pNew->pFile = (CrashFile *)pFile;
  if( zBuf ){
    pNew->zBuf = (u8 *)&pNew[1];
    memcpy(pNew->zBuf, zBuf, nBuf);
  }

  if( g.pWriteList ){
    WriteBuffer *pEnd;
    for(pEnd=g.pWriteList; pEnd->pNext; pEnd=pEnd->pNext);
    pEnd->pNext = pNew;
  }else{
    g.pWriteList = pNew;
  }

  
  return SQLITE_OK;
}

/*
** Close a crash-file.
*/
static int cfClose(sqlite3_file *pFile){
  CrashFile *pCrash = (CrashFile *)pFile;
  writeListSync(pCrash, 0);
  sqlite3OsClose(&pCrash->pRealFile);
  return SQLITE_OK;
}

/*
** Read data from a crash-file.
*/
static int cfRead(
................................................................................
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  CrashFile *pCrash = (CrashFile *)pFile;
  sqlite3_int64 iSize;
  int rc;
  WriteBuffer *pWrite;

  /* Check the file-size to see if this is a short-read */
  rc = sqlite3OsFileSize(pFile, &iSize);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  if( iSize<(iOfst+iAmt) ){
    return SQLITE_IOERR_SHORT_READ;
  }

  /* Zero the output buffer */
  memset(zBuf, 0, iAmt);

  /* Read some data from the real file */
  rc = sqlite3OsFileSize(pCrash->pRealFile, &iSize);
  if( rc==SQLITE_OK && iSize>iOfst ){
    int nRead = iAmt;
    if( iSize<(iOfst+iAmt) ){
      nRead = iSize - iOfst;
    }
    rc = sqlite3OsRead(pCrash->pRealFile, zBuf, nRead, iOfst);
  }

  /* Fill in the buffer by traversing the write-list */
  for(pWrite=g.pWriteList; rc==SQLITE_OK && pWrite; pWrite=pWrite->pNext){
    if( pWrite->pFile==pCrash ){
      int iWriteOffset;
      int nWriteBuf;
      u8 *zWriteBuf;

      iWriteOffset = pWrite->iOffset - iOfst;
      nWriteBuf = pWrite->nBuf;
      zWriteBuf = pWrite->zBuf;
      if( iWriteOffset<0 ){
        nWriteBuf += iWriteOffset;
        zWriteBuf -= iWriteOffset;
        iWriteOffset = 0;
      }
      if( (iWriteOffset+nWriteBuf)>iAmt ){
        nWriteBuf = iAmt - iWriteOffset;
      }
      
      if( pWrite->zBuf && nWriteBuf>0){
        /* Copy data to the buffer */
        memcpy(&((u8 *)zBuf)[iWriteOffset], zWriteBuf, nWriteBuf);
      }

      if( pWrite->zBuf==0 && iWriteOffset<iAmt ){
        /* Zero part of the buffer to simulate a truncate */
        memset(&((u8 *)zBuf)[iWriteOffset], 0, iAmt-iWriteOffset);
      }
    }
  }


  return rc;
}

/*
** Write data to a crash-file.
*/
static int cfWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
















  return writeListAppend(pFile, iOfst, zBuf, iAmt);
}

/*
** Truncate a crash-file.
*/
static int cfTruncate(sqlite3_file *pFile, sqlite_int64 size){





  return writeListAppend(pFile, size, 0, 0);
}

/*
** Sync a crash-file.
*/
static int cfSync(sqlite3_file *pFile, int flags){
  CrashFile *pCrash = (CrashFile *)pFile;
  int isCrash = 0;

  if( 0==strcmp(pCrash->zName, g.zCrashFile) ){
    if( (--g.iCrash==0) ){




      isCrash = 1;

    }



  }

  return writeListSync(pCrash, isCrash);
}

/*
** Return the current file-size of the crash-file.
*/
static int cfFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  CrashFile *pCrash = (CrashFile *)pFile;
  WriteBuffer *pWrite;
  int rc;
  sqlite_int64 iSize;

  rc = sqlite3OsFileSize(pCrash->pRealFile, &iSize);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext){
    sqlite_int64 iEnd = pWrite->nBuf+pWrite->iOffset;
    if( pWrite->pFile==pCrash && (pWrite->zBuf==0 || iEnd>iSize) ){
      iSize = iEnd;
    }
  }
  *pSize = iSize;

  return SQLITE_OK;
}

/*
** Calls related to file-locks are passed on to the real file handle.
*/
static int cfLock(sqlite3_file *pFile, int eLock){
................................................................................
}
static int cfUnlock(sqlite3_file *pFile, int eLock){
  return sqlite3OsUnlock(((CrashFile *)pFile)->pRealFile, eLock);
}
static int cfCheckReservedLock(sqlite3_file *pFile){
  return sqlite3OsCheckReservedLock(((CrashFile *)pFile)->pRealFile);
}



static int cfBreakLock(sqlite3_file *pFile){
  return sqlite3OsBreakLock(((CrashFile *)pFile)->pRealFile);
}

/*
** The xSectorSize() and xDeviceCharacteristics() functions return
** the global values configured by the [sqlite_crashparams] tcl
................................................................................
  cfTruncate,                   /* xTruncate */
  cfSync,                       /* xSync */
  cfFileSize,                   /* xFileSize */
  cfLock,                       /* xLock */
  cfUnlock,                     /* xUnlock */
  cfCheckReservedLock,          /* xCheckReservedLock */
  cfBreakLock,                  /* xBreakLock */

  cfSectorSize,                 /* xSectorSize */
  cfDeviceCharacteristics       /* xDeviceCharacteristics */
};

/*
** Open a crash-file file handle. The vfs pVfs is used to open
** the underlying real file.






*/
int sqlite3CrashFileOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){


  CrashFile *pWrapper = (CrashFile *)pFile;
  int rc = SQLITE_NOMEM;
  sqlite3_file *pReal;
  pReal = (sqlite3_file *)sqlite3_malloc(pVfs->szOsFile);
  if( pReal ){






    pWrapper->pMethod = &CrashFileVtab;
    pWrapper->zName = (char *)zName;
    rc = pVfs->xOpen(pVfs->pAppData, zName, pReal, flags, pOutFlags);




    if( rc==SQLITE_OK ){


      pWrapper->pRealFile = pFile;


    }else{
      sqlite3_free(pReal);

    }






  }
  return rc;
}

int sqlite3CrashFileWrap(
  sqlite3_file *pFile,
  const char *zName,
  sqlite3_file **ppWrapper
){
  CrashFile *pWrapper;
  pWrapper = (CrashFile *)sqlite3_malloc(sizeof(CrashFile)+strlen(zName)+1);
  if( !pWrapper ){
    return SQLITE_NOMEM;
  }

  pWrapper->pMethod = &CrashFileVtab;
  pWrapper->pRealFile = pFile;
  pWrapper->zName = (char *)&pWrapper[1];
  memcpy(pWrapper->zName, zName, strlen(zName)+1);

  *ppWrapper = (sqlite3_file *)pWrapper;
  return SQLITE_OK;
}


int sqlite3CrashFileSize(){
  return (int)sizeof(CrashFile);
}

/*
** tclcmd:   sqlite_crashparams ?OPTIONS? DELAY CRASHFILE
**
** This procedure implements a TCL command that enables crash testing
** in testfixture.  Once enabled, crash testing cannot be disabled.
**
** Available options are "-characteristics" and "-sectorsize". Both require
................................................................................
  };
  
  if( objc<3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?OPTIONS? DELAY CRASHFILE");
    goto error;
  }

  pVfs = sqlite3_find_vfs(0);
  zCrashFile = sqlite3_malloc(pVfs->mxPathname);
  sqlite3OsFullPathname(pVfs, Tcl_GetString(objv[objc-1]), zCrashFile);
  nCrashFile = strlen(zCrashFile);
  if( nCrashFile>=sizeof(g.zCrashFile) ){
    Tcl_AppendResult(interp, "Filename is too long: \"", zCrashFile, "\"", 0);
    goto error;
  }
  if( Tcl_GetIntFromObj(interp, objv[objc-2], &iDelay) ){
    goto error;
  }
................................................................................
    g.iDeviceCharacteristics = iDc;
  }
  if( setSectorsize ){
    g.iSectorSize = iSectorSize;
  }
  g.iCrash = iDelay;
  memcpy(g.zCrashFile, zCrashFile, nCrashFile+1);
  sqlite3_free(zCrashFile);
  sqlite3CrashTestEnable = 1;
  return TCL_OK;

error:
  sqlite3_free(zCrashFile);
  return TCL_ERROR;
}

#endif /* SQLITE_OMIT_DISKIO */

/*
** This procedure registers the TCL procedures defined in this file.

  WriteBuffer *pNext;          /* Next in CrashGlobal.pWriteList */
};

struct CrashFile {
  const sqlite3_io_methods *pMethod;   /* Must be first */
  sqlite3_file *pRealFile;             /* Underlying "real" file handle */
  char *zName;

  /* Cache of the entire file. */
  int iSize;                           /* Size of file in bytes */
  int nData;                           /* Size of buffer allocated at zData */
  u8 *zData;                           /* Buffer containing file contents */
};

struct CrashGlobal {
  WriteBuffer *pWriteList;     /* Head of write-list */
  WriteBuffer *pWriteListEnd;  /* End of write-list */

  int iSectorSize;             /* Value of simulated sector size */
  int iDeviceCharacteristics;  /* Value of simulated device characteristics */

  int iCrash;                  /* Crash on the iCrash'th call to xSync() */
  char zCrashFile[500];        /* Crash during an xSync() on this file */ 
};

static CrashGlobal g = {0, 0, SQLITE_DEFAULT_SECTOR_SIZE, 0, 0};

/*
** Set this global variable to 1 to enable crash testing.
*/
static int sqlite3CrashTestEnable = 0;

/*
** Flush the write-list as if xSync() had been called on file handle
** pFile. If isCrash is true, simulate a crash.
*/
static int writeListSync(CrashFile *pFile, int isCrash){
  int rc = SQLITE_OK;
  int iDc = g.iDeviceCharacteristics;
  i64 iSize;

  WriteBuffer *pWrite;
  WriteBuffer **ppPtr;

  /* Set pFinal to point to the last element of the write-list that
  ** is associated with file handle pFile.
  */
................................................................................
    for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext){
      if( pWrite->pFile==pFile ){
        pFinal = pWrite;
      }
    }
  }

  sqlite3OsFileSize((sqlite3_file *)pFile, &iSize);

  ppPtr = &g.pWriteList;
  for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){
    sqlite3_file *pRealFile = pWrite->pFile->pRealFile;

    /* (eAction==1)      -> write block out normally,
    ** (eAction==2)      -> do nothing,
    ** (eAction==3)      -> trash sectors.
    */
    int eAction = 0;
    if( !isCrash ){
................................................................................
      }
    }

    switch( eAction ){
      case 1: {               /* Write out correctly */
        if( pWrite->zBuf ){
          rc = sqlite3OsWrite(
              pRealFile, pWrite->zBuf, pWrite->nBuf, pWrite->iOffset
          );
        }else{
          rc = sqlite3OsTruncate(pRealFile, pWrite->iOffset);
        }
        *ppPtr = pWrite->pNext;
        sqlite3_free(pWrite);
        break;
      }
      case 2: {               /* Do nothing */
        ppPtr = &pWrite->pNext;
        break;
      }
      case 3: {               /* Trash sectors */
        u8 *zGarbage;
        int iFirst = (pWrite->iOffset/g.iSectorSize);
        int iLast = (pWrite->iOffset+pWrite->nBuf-1)/g.iSectorSize;

        assert(pWrite->zBuf);

        zGarbage = sqlite3_malloc(g.iSectorSize);
        if( zGarbage ){
          sqlite3_int64 i;
          for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
            sqlite3Randomness(g.iSectorSize, zGarbage); 
            rc = sqlite3OsWrite(
              pRealFile, zGarbage, g.iSectorSize, i*g.iSectorSize
            );
          }
          sqlite3_free(zGarbage);
        }else{
          rc = SQLITE_NOMEM;
        }

................................................................................

    if( pWrite==pFinal ) break;
  }

  if( rc==SQLITE_OK && isCrash ){
    exit(-1);
  }

  for(pWrite=g.pWriteList; pWrite && pWrite->pNext; pWrite=pWrite->pNext);
  g.pWriteListEnd = pWrite;

  return rc;
}

/*
** Add an entry to the end of the write-list.
*/
................................................................................
  pNew->pFile = (CrashFile *)pFile;
  if( zBuf ){
    pNew->zBuf = (u8 *)&pNew[1];
    memcpy(pNew->zBuf, zBuf, nBuf);
  }

  if( g.pWriteList ){
    assert(g.pWriteListEnd);

    g.pWriteListEnd->pNext = pNew;
  }else{
    g.pWriteList = pNew;
  }
  g.pWriteListEnd = pNew;
  
  return SQLITE_OK;
}

/*
** Close a crash-file.
*/
static int cfClose(sqlite3_file *pFile){
  CrashFile *pCrash = (CrashFile *)pFile;
  writeListSync(pCrash, 0);
  sqlite3OsCloseFree(pCrash->pRealFile);
  return SQLITE_OK;
}

/*
** Read data from a crash-file.
*/
static int cfRead(
................................................................................
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  CrashFile *pCrash = (CrashFile *)pFile;
  sqlite3_int64 iSize;

  WriteBuffer *pWrite;

  /* Check the file-size to see if this is a short-read */




  if( pCrash->iSize<(iOfst+iAmt) ){
    return SQLITE_IOERR_SHORT_READ;
  }













































  memcpy(zBuf, &pCrash->zData[iOfst], iAmt);
  return SQLITE_OK;
}

/*
** Write data to a crash-file.
*/
static int cfWrite(
  sqlite3_file *pFile, 
  const void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  CrashFile *pCrash = (CrashFile *)pFile;
  if( iAmt+iOfst>pCrash->iSize ){
    pCrash->iSize = iAmt+iOfst;
  }
  while( pCrash->iSize>pCrash->nData ){
    char *zNew;
    int nNew = (pCrash->nData*2) + 4096;
    zNew = (char *)sqlite3_realloc(pCrash->zData, nNew);
    if( !zNew ){
      return SQLITE_NOMEM;
    }
    memset(&zNew[pCrash->nData], 0, nNew-pCrash->nData);
    pCrash->nData = nNew;
    pCrash->zData = zNew;
  }
  memcpy(&pCrash->zData[iOfst], zBuf, iAmt);
  return writeListAppend(pFile, iOfst, zBuf, iAmt);
}

/*
** Truncate a crash-file.
*/
static int cfTruncate(sqlite3_file *pFile, sqlite_int64 size){
  CrashFile *pCrash = (CrashFile *)pFile;
  assert(size>=0);
  if( pCrash->iSize>size ){
    pCrash->iSize = size;
  }
  return writeListAppend(pFile, size, 0, 0);
}

/*
** Sync a crash-file.
*/
static int cfSync(sqlite3_file *pFile, int flags){
  CrashFile *pCrash = (CrashFile *)pFile;
  int isCrash = 0;

  const char *zName = pCrash->zName;
  const char *zCrashFile = g.zCrashFile;
  int nName = strlen(zName);
  int nCrashFile = strlen(zCrashFile);

  if( nCrashFile>0 && zCrashFile[nCrashFile-1]=='*' ){
    nCrashFile--;
    if( nName>nCrashFile ) nName = nCrashFile;
  }

  if( nName==nCrashFile && 0==memcmp(zName, zCrashFile, nName) ){
    if( (--g.iCrash)==0 ) isCrash = 1;
  }

  return writeListSync(pCrash, isCrash);
}

/*
** Return the current file-size of the crash-file.
*/
static int cfFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  CrashFile *pCrash = (CrashFile *)pFile;















  *pSize = (i64)pCrash->iSize;

  return SQLITE_OK;
}

/*
** Calls related to file-locks are passed on to the real file handle.
*/
static int cfLock(sqlite3_file *pFile, int eLock){
................................................................................
}
static int cfUnlock(sqlite3_file *pFile, int eLock){
  return sqlite3OsUnlock(((CrashFile *)pFile)->pRealFile, eLock);
}
static int cfCheckReservedLock(sqlite3_file *pFile){
  return sqlite3OsCheckReservedLock(((CrashFile *)pFile)->pRealFile);
}
static int cfLockState(sqlite3_file *pFile){
  return sqlite3OsLockState(((CrashFile *)pFile)->pRealFile);
}
static int cfBreakLock(sqlite3_file *pFile){
  return sqlite3OsBreakLock(((CrashFile *)pFile)->pRealFile);
}

/*
** The xSectorSize() and xDeviceCharacteristics() functions return
** the global values configured by the [sqlite_crashparams] tcl
................................................................................
  cfTruncate,                   /* xTruncate */
  cfSync,                       /* xSync */
  cfFileSize,                   /* xFileSize */
  cfLock,                       /* xLock */
  cfUnlock,                     /* xUnlock */
  cfCheckReservedLock,          /* xCheckReservedLock */
  cfBreakLock,                  /* xBreakLock */
  cfLockState,                  /* xLockState */
  cfSectorSize,                 /* xSectorSize */
  cfDeviceCharacteristics       /* xDeviceCharacteristics */
};

/*
** Open a crash-file file handle. The vfs pVfs is used to open
** the underlying real file.
**
** The caller will have allocated pVfs->szOsFile bytes of space
** at pFile. This file uses this space for the CrashFile structure
** and allocates space for the "real" file structure using 
** sqlite3_malloc(). The assumption here is (pVfs->szOsFile) is
** equal or greater than sizeof(CrashFile).
*/
int sqlite3CrashFileOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){
  int rc;
  if( sqlite3CrashTestEnable ){
    CrashFile *pWrapper = (CrashFile *)pFile;

    sqlite3_file *pReal;

    assert(pVfs->szOsFile>=sizeof(CrashFile));
    memset(pWrapper, 0, sizeof(CrashFile));
    sqlite3CrashTestEnable = 0;
    rc = sqlite3OsOpenMalloc(pVfs, zName, &pReal, flags, pOutFlags);
    sqlite3CrashTestEnable = 1;
    if( rc==SQLITE_OK ){
      i64 iSize;
      pWrapper->pMethod = &CrashFileVtab;
      pWrapper->zName = (char *)zName;

      pWrapper->pRealFile = pReal;
      rc = sqlite3OsFileSize(pReal, &iSize);
      pWrapper->iSize = (int)iSize;
    }
    if( rc==SQLITE_OK ){
      pWrapper->nData = (4096 + pWrapper->iSize);
      pWrapper->zData = (char *)sqlite3_malloc(pWrapper->nData);
      if( pWrapper->zData ){
        memset(pWrapper->zData, 0, pWrapper->nData);
        rc = sqlite3OsRead(pReal, pWrapper->zData, pWrapper->iSize, 0); 
      }else{

        rc = SQLITE_NOMEM;
      }
    }
    if( rc!=SQLITE_OK && pWrapper->pMethod ){
      sqlite3OsClose(pFile);
    }
  }else{
    rc = pVfs->xOpen(pVfs->pAppData, zName, pFile, flags, pOutFlags);
  }
  return rc;
}


























/*
** tclcmd:   sqlite_crashparams ?OPTIONS? DELAY CRASHFILE
**
** This procedure implements a TCL command that enables crash testing
** in testfixture.  Once enabled, crash testing cannot be disabled.
**
** Available options are "-characteristics" and "-sectorsize". Both require
................................................................................
  };
  
  if( objc<3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?OPTIONS? DELAY CRASHFILE");
    goto error;
  }

  zCrashFile = Tcl_GetStringFromObj(objv[objc-1], &nCrashFile);



  if( nCrashFile>=sizeof(g.zCrashFile) ){
    Tcl_AppendResult(interp, "Filename is too long: \"", zCrashFile, "\"", 0);
    goto error;
  }
  if( Tcl_GetIntFromObj(interp, objv[objc-2], &iDelay) ){
    goto error;
  }
................................................................................
    g.iDeviceCharacteristics = iDc;
  }
  if( setSectorsize ){
    g.iSectorSize = iSectorSize;
  }
  g.iCrash = iDelay;
  memcpy(g.zCrashFile, zCrashFile, nCrashFile+1);

  sqlite3CrashTestEnable = 1;
  return TCL_OK;

error:

  return TCL_ERROR;
}

#endif /* SQLITE_OMIT_DISKIO */

/*
** This procedure registers the TCL procedures defined in this file.

        return SQLITE_NOMEM;
      }
    }while( sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS) );

    /* Open the master journal. */
    rc = sqlite3OsOpenMalloc(pVfs, zMaster, &pMaster, 
        SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
        SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_MASTER_JOURNAL
    );
    if( rc!=SQLITE_OK ){
      sqlite3_free(zMaster);
      return rc;
    }
 
    /* Write the name of each database file in the transaction into the new

        return SQLITE_NOMEM;
      }
    }while( sqlite3OsAccess(pVfs, zMaster, SQLITE_ACCESS_EXISTS) );

    /* Open the master journal. */
    rc = sqlite3OsOpenMalloc(pVfs, zMaster, &pMaster, 
        SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|
        SQLITE_OPEN_EXCLUSIVE|SQLITE_OPEN_MASTER_JOURNAL, 0
    );
    if( rc!=SQLITE_OK ){
      sqlite3_free(zMaster);
      return rc;
    }
 
    /* Write the name of each database file in the transaction into the new

# The focus of this file is testing the ability of the database to
# uses its rollback journal to recover intact (no database corruption)
# from a power failure during the middle of a COMMIT.  The OS interface
# modules are overloaded using the modified I/O routines found in test6.c.  
# These routines allow us to simulate the kind of file damage that 
# occurs after a power failure.
#
# $Id: crash.test,v 1.24 2007/05/23 06:25:13 danielk1977 Exp $

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

ifcapable !crashtest {
  finish_test
  return
}

set repeats 100
# set repeats 10

# The following procedure computes a "signature" for table "abc".  If
# abc changes in any way, the signature should change.  
proc signature {} {
  return [db eval {SELECT count(*), md5sum(a), md5sum(b), md5sum(c) FROM abc}]
}
proc signature2 {} {

# The focus of this file is testing the ability of the database to
# uses its rollback journal to recover intact (no database corruption)
# from a power failure during the middle of a COMMIT.  The OS interface
# modules are overloaded using the modified I/O routines found in test6.c.  
# These routines allow us to simulate the kind of file damage that 
# occurs after a power failure.
#
# $Id: crash.test,v 1.25 2007/08/20 14:23:44 danielk1977 Exp $

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

ifcapable !crashtest {
  finish_test
  return
}

set repeats 100
#set repeats 10

# The following procedure computes a "signature" for table "abc".  If
# abc changes in any way, the signature should change.  
proc signature {} {
  return [db eval {SELECT count(*), md5sum(a), md5sum(b), md5sum(c) FROM abc}]
}
proc signature2 {} {

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.83 2007/08/16 13:01:45 drh Exp $

# Make sure tclsqlite3 was compiled correctly.  Abort now with an
# error message if not.
#
if {[sqlite3 -tcl-uses-utf]} {
  if {"\u1234"=="u1234"} {
    puts stderr "***** BUILD PROBLEM *****"
................................................................................
  for {set ii 0} {$ii < [llength $args]-1} {incr ii 2} {
    set z [lindex $args $ii]
    set n [string length $z]
    set z2 [lindex $args [expr $ii+1]]

    if     {$n>1 && [string first $z -delay]==0}     {set crashdelay $z2} \
    elseif {$n>1 && [string first $z -file]==0}      {set crashfile $z2}  \
    elseif {$n>1 && [string first $z -blocksize]==0} {set blocksize $z2}  \
    else   { error "Unrecognized option: $z" }
  }

  if {$crashfile eq ""} {
    error "Compulsory option -file missing"
  }

  set cfile [file join [pwd] $crashfile]

  set f [open crash.tcl w]
  puts $f "sqlite3_crashparams $crashdelay $cfile $blocksize"
  puts $f "set sqlite_pending_byte $::sqlite_pending_byte"
  puts $f "sqlite3 db test.db"

  # This block sets the cache size of the main database to 10
  # pages. This is done in case the build is configured to omit
  # "PRAGMA cache_size".
  puts $f {db eval {SELECT * FROM sqlite_master;}}

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.84 2007/08/20 14:23:44 danielk1977 Exp $

# Make sure tclsqlite3 was compiled correctly.  Abort now with an
# error message if not.
#
if {[sqlite3 -tcl-uses-utf]} {
  if {"\u1234"=="u1234"} {
    puts stderr "***** BUILD PROBLEM *****"
................................................................................
  for {set ii 0} {$ii < [llength $args]-1} {incr ii 2} {
    set z [lindex $args $ii]
    set n [string length $z]
    set z2 [lindex $args [expr $ii+1]]

    if     {$n>1 && [string first $z -delay]==0}     {set crashdelay $z2} \
    elseif {$n>1 && [string first $z -file]==0}      {set crashfile $z2}  \
    elseif {$n>1 && [string first $z -blocksize]==0} {set blocksize "-s $z2" } \
    else   { error "Unrecognized option: $z" }
  }

  if {$crashfile eq ""} {
    error "Compulsory option -file missing"
  }

  set cfile [file join [pwd] $crashfile]

  set f [open crash.tcl w]
  puts $f "sqlite3_crashparams $blocksize $crashdelay $cfile"
  puts $f "set sqlite_pending_byte $::sqlite_pending_byte"
  puts $f "sqlite3 db test.db"

  # This block sets the cache size of the main database to 10
  # pages. This is done in case the build is configured to omit
  # "PRAGMA cache_size".
  puts $f {db eval {SELECT * FROM sqlite_master;}}