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Overview
Comment:Back out the new device capability. The determination of whether or not a file has moved is now done strictly using a file-control.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | detect-moved-db
Files: files | file ages | folders
SHA1: 9c59f5af7ac4908583fab85d37241f200c40f02d
User & Date: drh 2013-12-07 16:45:05
Context
2013-12-07
16:56
At the start of each journaled write transaction, check to see if the database file has been moved, and if it has refuse to start the transaction, returning an SQLITE_READONLY_DBMOVED error code. Writing to a moved or renamed database is still allowed when journal_mode is OFF or MEMORY. check-in: 369a23e0 user: drh tags: trunk
16:45
Back out the new device capability. The determination of whether or not a file has moved is now done strictly using a file-control. Closed-Leaf check-in: 9c59f5af user: drh tags: detect-moved-db
12:29
Actually look at i-node numbers to determine whether or not the database file has moved. check-in: 2b1884dc user: drh tags: detect-moved-db
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/os_win.c.

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/*
** Return a vector of device characteristics.
*/
static int winDeviceCharacteristics(sqlite3_file *id){
  winFile *p = (winFile*)id;
  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN |
         SQLITE_IOCAP_UNMOVABLE_WHEN_OPEN |
         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
}

/* 
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.
** During sqlite3_os_init() we do a GetSystemInfo()







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/*
** Return a vector of device characteristics.
*/
static int winDeviceCharacteristics(sqlite3_file *id){
  winFile *p = (winFile*)id;
  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN |

         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
}

/* 
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.
** During sqlite3_os_init() we do a GetSystemInfo()

Changes to src/pager.c.

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/* Verify that the database file has not be deleted or renamed out from
** under the pager.  Return SQLITE_OK if the database is still were it ought
** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
** code from sqlite3OsAccess()) if the database has gone missing.
*/
static int databaseIsUnmoved(Pager *pPager){
  const int fixedFlags = SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN |
                         SQLITE_IOCAP_UNMOVABLE_WHEN_OPEN;
  int dc;
  int bHasMoved = 0;
  int rc;

  if( pPager->tempFile ) return SQLITE_OK;
  if( pPager->dbSize==0 ) return SQLITE_OK;
  assert( pPager->zFilename && pPager->zFilename[0] );
  dc = sqlite3OsDeviceCharacteristics(pPager->fd);
  if( (dc&fixedFlags)==fixedFlags ) return SQLITE_OK;
  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_HAS_MOVED, &bHasMoved);






  if( rc==SQLITE_OK && bHasMoved ) rc = SQLITE_READONLY_DBMOVED;

  return rc;
}


/*
** This function is called after transitioning from PAGER_UNLOCK to
** PAGER_SHARED state. It tests if there is a hot journal present in







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/* Verify that the database file has not be deleted or renamed out from
** under the pager.  Return SQLITE_OK if the database is still were it ought
** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
** code from sqlite3OsAccess()) if the database has gone missing.
*/
static int databaseIsUnmoved(Pager *pPager){



  int bHasMoved = 0;
  int rc;

  if( pPager->tempFile ) return SQLITE_OK;
  if( pPager->dbSize==0 ) return SQLITE_OK;
  assert( pPager->zFilename && pPager->zFilename[0] );


  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_HAS_MOVED, &bHasMoved);
  if( rc==SQLITE_NOTFOUND ){
    /* If the HAS_MOVED file-control is unimplemented, assume that the file
    ** has not been moved.  That is the historical behavior of SQLite: prior to
    ** version 3.8.3, it never checked */
    rc = SQLITE_OK;
  }else if( rc==SQLITE_OK && bHasMoved ){
    rc = SQLITE_READONLY_DBMOVED;
  }
  return rc;
}


/*
** This function is called after transitioning from PAGER_UNLOCK to
** PAGER_SHARED state. It tests if there is a hot journal present in

Changes to src/sqlite.h.in.

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** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
** information is written to disk in the same order as calls
** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
** after reboot following a crash or power loss, the only bytes in a
** file that were written at the application level might have changed
** and that adjacent bytes, even bytes within the same sector are
** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
** and SQLITE_IOCAP_UNMOVABLE_WHEN_OPEN flags indicate that a file 
** cannot be deleted or renamed when open, respectively.
*/
#define SQLITE_IOCAP_ATOMIC                 0x00000001
#define SQLITE_IOCAP_ATOMIC512              0x00000002
#define SQLITE_IOCAP_ATOMIC1K               0x00000004
#define SQLITE_IOCAP_ATOMIC2K               0x00000008
#define SQLITE_IOCAP_ATOMIC4K               0x00000010
#define SQLITE_IOCAP_ATOMIC8K               0x00000020
................................................................................
#define SQLITE_IOCAP_ATOMIC16K              0x00000040
#define SQLITE_IOCAP_ATOMIC32K              0x00000080
#define SQLITE_IOCAP_ATOMIC64K              0x00000100
#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
#define SQLITE_IOCAP_UNMOVABLE_WHEN_OPEN    0x00002000

/*
** CAPI3REF: File Locking Levels
**
** SQLite uses one of these integer values as the second
** argument to calls it makes to the xLock() and xUnlock() methods
** of an [sqlite3_io_methods] object.







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** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
** information is written to disk in the same order as calls
** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
** after reboot following a crash or power loss, the only bytes in a
** file that were written at the application level might have changed
** and that adjacent bytes, even bytes within the same sector are
** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
** flag indicate that a file cannot be deleted when open.

*/
#define SQLITE_IOCAP_ATOMIC                 0x00000001
#define SQLITE_IOCAP_ATOMIC512              0x00000002
#define SQLITE_IOCAP_ATOMIC1K               0x00000004
#define SQLITE_IOCAP_ATOMIC2K               0x00000008
#define SQLITE_IOCAP_ATOMIC4K               0x00000010
#define SQLITE_IOCAP_ATOMIC8K               0x00000020
................................................................................
#define SQLITE_IOCAP_ATOMIC16K              0x00000040
#define SQLITE_IOCAP_ATOMIC32K              0x00000080
#define SQLITE_IOCAP_ATOMIC64K              0x00000100
#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000


/*
** CAPI3REF: File Locking Levels
**
** SQLite uses one of these integer values as the second
** argument to calls it makes to the xLock() and xUnlock() methods
** of an [sqlite3_io_methods] object.