SQLite

      ** file the database must be corrupt. */
      return SQLITE_CORRUPT_BKPT;
    }
    if( nOvfl ){
      rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
      if( rc ) return rc;
    }

    if( (pOvfl || (pOvfl = btreePageLookup(pBt, ovflPgno)))
     && sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
    ){
      /* There is no reason any cursor should have an outstanding reference 
      ** to an overflow page belonging to a cell that is being deleted/updated.
      ** So if there exists more than one reference to this page, then it 
      ** must not really be an overflow page and the database must be corrupt. 
      ** It is helpful to detect this before calling freePage2(), as 
      ** freePage2() may zero the page contents if secure-delete mode is
      ** enabled. If this 'overflow' page happens to be a page that the
      ** caller is iterating through or using in some other way, this
      ** can be problematic.
      */
      rc = SQLITE_CORRUPT_BKPT;
    }else{
      rc = freePage2(pBt, pOvfl, ovflPgno);
    }

    if( pOvfl ){
      sqlite3PagerUnref(pOvfl->pDbPage);
    }
    if( rc ) return rc;
    ovflPgno = iNext;
  }
  return SQLITE_OK;

# 2004 August 30 {}
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    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.

while {[string length $junk]<256} {append junk $junk}
set junk [string range $junk 0 255]

# Go through the database and write garbage data into each 256 segment
# of the file.  Then do various operations on the file to make sure that
# the database engine can recover gracefully from the corruption.
#
for {set i [expr {1*256}]} {0 && $i<$fsize-256} {incr i 256} {
  set tn [expr {$i/256}]
  db close
  copy_file test.bu test.db
  set fd [open test.db r+]
  fconfigure $fd -translation binary
  seek $fd $i
  puts -nonewline $fd $junk

  do_test corrupt-7.3 {
    catchsql {
      INSERT INTO t1 VALUES(X'000100020003000400050006000700080009000A');
    }
  } {1 {database disk image is malformed}}
}

db close
file delete -force test.db test.db-journal
do_test corrupt-8.1 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    PRAGMA secure_delete = on;
    PRAGMA auto_vacuum = 0;
    CREATE TABLE t1(x INTEGER PRIMARY KEY, y);
    INSERT INTO t1 VALUES(5, randomblob(1900));
  }

  hexio_write test.db 2044 [hexio_render_int32 2]
  hexio_write test.db 24   [hexio_render_int32 45]

  catchsql { INSERT OR REPLACE INTO t1 VALUES(5, randomblob(1900)) }
} {1 {database disk image is malformed}}

finish_test