SQLite

** 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 1.315 2007/04/02 11:08:59 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

        rc = SQLITE_BUSY;
        if( sqlite3OsFileExists(pPager->zJournal) ){
          int ro;
          assert( !pPager->tempFile );
          rc = sqlite3OsOpenReadWrite(pPager->zJournal, &pPager->jfd, &ro);
          if( ro ){
            rc = SQLITE_BUSY;
            sqlite3OsClose(&pPager->jfd);
          }
        }
        if( rc!=SQLITE_OK ){
          pager_unlock(pPager);
          return SQLITE_BUSY;
        }
        pPager->journalOpen = 1;

        ** must be discarded.
        */

        PgHdr *pPage1 = pager_lookup(pPager, 1);
        if( pPage1 ){
          unlinkPage(pPage1);

          /* Make sure the former page 1 is right at the start of the
          ** free-list. This triggers a special case in pagerAllocatePage()
          ** to re-use this page even if the total number of pages in
          ** the cache is less than Pager.mxPage.
          */
          assert( pPager->pFirst==pPager->pFirstSynced );
          pPage1->pNextFree = pPager->pFirst;
          if( pPager->pFirst ){
            pPager->pFirst->pPrevFree = pPage1;
          }else{
            assert( !pPager->pLast );
            pPager->pLast = pPage1;
          }
          pPager->pFirst = pPage1;
          pPager->pFirstSynced = pPage1;

        }

        assert( !pager_lookup(pPager, 1) );
        rc = sqlite3PagerAcquire(pPager, 1, &pPage1, 0);
        if( rc==SQLITE_OK ){
	  /* The change-counter is stored at offset 24. See also
          ** pager_incr_changecounter().

# 2006 September 4
#
# 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.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# $Id: misc7.test,v 1.11 2007/04/02 11:08:59 danielk1977 Exp $

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

do_test misc7-1 {
  c_misuse_test
} {}

    set msg
  } else {
    error $msg
  }
}

sqlite3 db test.db

do_test misc7-16.X {
  execsql {
    SELECT count(*) FROM t3;
  }
} {32}

set sqlite_pager_n_sort_bucket 4
do_test misc7-17 {
  execsql {
    PRAGMA integrity_check;
    VACUUM;
    PRAGMA integrity_check;
  }
} {ok ok}
set sqlite_pager_n_sort_bucket 0

#----------------------------------------------------------------------
# Test the situation where a hot-journal is discovered but write-access
# to it is denied. This should return SQLITE_BUSY.
#
do_test misc7-17.1 {
  execsql {
    BEGIN;
    DELETE FROM t3 WHERE (oid%3)==0;
  }
  copy_file test.db bak.db
  copy_file test.db-journal bak.db-journal
  execsql {
    COMMIT;
  }

  copy_file bak.db test.db
  copy_file bak.db-journal test.db-journal
  file attributes test.db-journal -permissions r--------

  catchsql {
    SELECT count(*) FROM t3;
  }
} {1 {database is locked}}
do_test misc7-17.2 {
  file attributes test.db-journal -permissions rw-------
  catchsql {
    SELECT count(*) FROM t3;
  }
} {0 28}

finish_test