sqlite3OsEnterMutex();
  n = strlen(zCrashFile);
  if( zCrashFile[n-1]=='*' ){
    n--;
  }else if( strlen(zPath)>n ){
    n = strlen(zPath);
  }
  r = ( 
    iCrashDelay>0 &&
    !strncmp(zPath, zCrashFile, n) &&
    --iCrashDelay==0

  )?1:0;


  sqlite3OsLeaveMutex();
  return r;
}


static OsTestFile *pAllFiles = 0;

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

/*
** Load block 'blk' into the cache of pFile.
*/
static int cacheBlock(OsTestFile *pFile, int blk){
  if( blk>=pFile->nBlk ){
    int n = ((pFile->nBlk * 2) + 100 + blk);

    pFile->apBlk = (u8 **)sqliteRealloc(pFile->apBlk, n * sizeof(u8*));
    if( !pFile->apBlk ) return SQLITE_NOMEM;
    memset(&pFile->apBlk[pFile->nBlk], 0, (n - pFile->nBlk)*sizeof(u8*));
    pFile->nBlk = n;
  }

  if( !pFile->apBlk[blk] ){
................................................................................

/*
** Close the file.
*/
int sqlite3OsClose(OsFile *id){
  if( !(*id) ) return SQLITE_OK;
  if( (*id)->fd.isOpen ){

    writeCache(*id);
    sqlite3RealClose(&(*id)->fd);
  }
  closeFile(id);
  return SQLITE_OK;
}

................................................................................
}

/*
** Sync the file. First flush the write-cache to disk, then call the
** real sync() function.
*/
int sqlite3OsSync(OsFile *id){


  int rc = writeCache(*id);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3RealSync(&(*id)->fd);
  return rc;
}

/*
** Truncate the file. Set the internal OsFile.nMaxWrite variable to the new

  sqlite3OsEnterMutex();
  n = strlen(zCrashFile);
  if( zCrashFile[n-1]=='*' ){
    n--;
  }else if( strlen(zPath)>n ){
    n = strlen(zPath);
  }
  r = 0;

  if( iCrashDelay>0 && strncmp(zPath, zCrashFile, n)==0 ){
    iCrashDelay--;
    if( iCrashDelay<=0 ){
      r = 1;
    }
  }
  sqlite3OsLeaveMutex();
  return r;
}


static OsTestFile *pAllFiles = 0;

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

/*
** Load block 'blk' into the cache of pFile.
*/
static int cacheBlock(OsTestFile *pFile, int blk){
  if( blk>=pFile->nBlk ){
    int n = ((pFile->nBlk * 2) + 100 + blk);
    /* if( pFile->nBlk==0 ){ printf("DIRTY %s\n", pFile->zName); } */
    pFile->apBlk = (u8 **)sqliteRealloc(pFile->apBlk, n * sizeof(u8*));
    if( !pFile->apBlk ) return SQLITE_NOMEM;
    memset(&pFile->apBlk[pFile->nBlk], 0, (n - pFile->nBlk)*sizeof(u8*));
    pFile->nBlk = n;
  }

  if( !pFile->apBlk[blk] ){
................................................................................

/*
** Close the file.
*/
int sqlite3OsClose(OsFile *id){
  if( !(*id) ) return SQLITE_OK;
  if( (*id)->fd.isOpen ){
    /* printf("CLOSE %s (%d blocks)\n", (*id)->zName, (*id)->nBlk); */
    writeCache(*id);
    sqlite3RealClose(&(*id)->fd);
  }
  closeFile(id);
  return SQLITE_OK;
}

................................................................................
}

/*
** Sync the file. First flush the write-cache to disk, then call the
** real sync() function.
*/
int sqlite3OsSync(OsFile *id){
  int rc;
  /* printf("SYNC %s (%d blocks)\n", (*id)->zName, (*id)->nBlk); */
  rc = writeCache(*id);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3RealSync(&(*id)->fd);
  return rc;
}

/*
** Truncate the file. Set the internal OsFile.nMaxWrite variable to the new

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.159 2004/08/19 13:29:15 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
  u8 readOnly;                /* True for a read-only database */
  u8 needSync;                /* True if an fsync() is needed on the journal */
  u8 dirtyCache;              /* True if cached pages have changed */
  u8 alwaysRollback;          /* Disable dont_rollback() for all pages */
  u8 memDb;                   /* True to inhibit all file I/O */
  u8 *aInJournal;             /* One bit for each page in the database file */
  u8 *aInStmt;                /* One bit for each page in the database */

  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
  PgHdr *pFirst, *pLast;      /* List of free pages */
  PgHdr *pFirstSynced;        /* First free page with PgHdr.needSync==0 */
  PgHdr *pAll;                /* List of all pages */
  PgHdr *pStmt;               /* List of pages in the statement subjournal */
  PgHdr *aHash[N_PG_HASH];    /* Hash table to map page number to PgHdr */
  off_t journalOff;           /* Current byte offset in the journal file */
  off_t journalHdr;           /* Byte offset to previous journal header */
  off_t stmtHdrOff;           /* First journal header written this statement */
  off_t stmtCksum;            /* cksumInit when statement was started */
  int sectorSize;             /* Assumed sector size during rollback */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
};

/*
** These are bits that can be set in Pager.errMask.
*/
#define PAGER_ERR_FULL     0x01  /* a write() failed */
#define PAGER_ERR_MEM      0x02  /* malloc() failed */
................................................................................
  rc = write32bits(&pPager->jfd, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(&pPager->jfd, cksum);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3OsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));

  return rc;
}

/*
** Add or remove a page from the list of all pages that are in the
** statement journal.
**

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.160 2004/08/21 19:20:42 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
  u8 readOnly;                /* True for a read-only database */
  u8 needSync;                /* True if an fsync() is needed on the journal */
  u8 dirtyCache;              /* True if cached pages have changed */
  u8 alwaysRollback;          /* Disable dont_rollback() for all pages */
  u8 memDb;                   /* True to inhibit all file I/O */
  u8 *aInJournal;             /* One bit for each page in the database file */
  u8 *aInStmt;                /* One bit for each page in the database */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
  PgHdr *pFirst, *pLast;      /* List of free pages */
  PgHdr *pFirstSynced;        /* First free page with PgHdr.needSync==0 */
  PgHdr *pAll;                /* List of all pages */
  PgHdr *pStmt;               /* List of pages in the statement subjournal */
  PgHdr *aHash[N_PG_HASH];    /* Hash table to map page number to PgHdr */
  off_t journalOff;           /* Current byte offset in the journal file */
  off_t journalHdr;           /* Byte offset to previous journal header */
  off_t stmtHdrOff;           /* First journal header written this statement */
  off_t stmtCksum;            /* cksumInit when statement was started */
  int sectorSize;             /* Assumed sector size during rollback */

};

/*
** These are bits that can be set in Pager.errMask.
*/
#define PAGER_ERR_FULL     0x01  /* a write() failed */
#define PAGER_ERR_MEM      0x02  /* malloc() failed */
................................................................................
  rc = write32bits(&pPager->jfd, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(&pPager->jfd, cksum);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3OsWrite(&pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
  pPager->needSync = 1;
  return rc;
}

/*
** Add or remove a page from the list of all pages that are in the
** statement journal.
**

# module "crashtest" compiled with the special "os_test.c" backend is used.
# The os_test.c simulates the kind of file corruption that can occur
# when writes are happening at the moment of power loss.
# 
# The special crash-test module with its os_test.c backend only works
# on Unix.
#
# $Id: crash.test,v 1.8 2004/08/21 17:54:46 drh Exp $

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

# set repeats 100
set repeats 10

................................................................................
    signature
  } $sig
  do_test crash-4.1.$i.3 {
    signature2
  } $sig2
} 
set i 0
set i 55
while {[incr i]} {
  set sig [signature]
  set sig2 [signature2]
  set ::fin 0
  do_test crash-4.2.$i.1 {
     set c [crashsql $i test2.db-journal "
       ATTACH 'test2.db' AS aux;

# module "crashtest" compiled with the special "os_test.c" backend is used.
# The os_test.c simulates the kind of file corruption that can occur
# when writes are happening at the moment of power loss.
# 
# The special crash-test module with its os_test.c backend only works
# on Unix.
#
# $Id: crash.test,v 1.9 2004/08/21 19:20:42 drh Exp $

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

# set repeats 100
set repeats 10

................................................................................
    signature
  } $sig
  do_test crash-4.1.$i.3 {
    signature2
  } $sig2
} 
set i 0

while {[incr i]} {
  set sig [signature]
  set sig2 [signature2]
  set ::fin 0
  do_test crash-4.2.$i.1 {
     set c [crashsql $i test2.db-journal "
       ATTACH 'test2.db' AS aux;