/ Check-in [7d2f6a1d]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Make sure we never try to "truncate" a file to a larger size. (CVS 4582)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 7d2f6a1d6c5ab89a3b65fbcaf172abf6d81e206b
User & Date: drh 2007-11-29 18:44:27
Context
2007-11-30
01:06
Add a few function requirements numbers to interfaces in the comments of sqlite3.h.in. This is experimental. (CVS 4583) check-in: b829a645 user: drh tags: trunk
2007-11-29
18:44
Make sure we never try to "truncate" a file to a larger size. (CVS 4582) check-in: 7d2f6a1d user: drh tags: trunk
18:36
Add the optional (and experimental) mmap() memory allocator in the mem4.c module. (CVS 4581) check-in: cfd683ac user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/pager.c.

14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
....
1642
1643
1644
1645
1646
1647
1648








1649
1650
1651
1652




1653

1654
1655
1656
1657
1658
1659
1660
** 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 1.396 2007/11/28 16:19:56 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*
................................................................................


static void pager_truncate_cache(Pager *pPager);

/*
** Truncate the main file of the given pager to the number of pages
** indicated. Also truncate the cached representation of the file.








*/
static int pager_truncate(Pager *pPager, int nPage){
  int rc = SQLITE_OK;
  if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){




    rc = sqlite3OsTruncate(pPager->fd, pPager->pageSize*(i64)nPage);

  }
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
    pager_truncate_cache(pPager);
  }
  return rc;
}







|







 







>
>
>
>
>
>
>
>




>
>
>
>
|
>







14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
....
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
** 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 1.397 2007/11/29 18:44:27 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*
................................................................................


static void pager_truncate_cache(Pager *pPager);

/*
** Truncate the main file of the given pager to the number of pages
** indicated. Also truncate the cached representation of the file.
**
** Might might be the case that the file on disk is smaller than nPage.
** This can happen, for example, if we are in the middle of a transaction
** which has extended the file size and the new pages are still all held
** in cache, then an INSERT or UPDATE does a statement rollback.  Some
** operating system implementations can get confused if you try to
** truncate a file to some size that is larger than it currently is,
** so detect this case and do not do the truncation.
*/
static int pager_truncate(Pager *pPager, int nPage){
  int rc = SQLITE_OK;
  if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){
    i64 currentSize, newSize;
    rc = sqlite3OsFileSize(pPager->fd, &currentSize);
    newSize = pPager->pageSize*(i64)nPage;
    if( rc==SQLITE_OK && currentSize>newSize ){
      rc = sqlite3OsTruncate(pPager->fd, newSize);
    }
  }
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
    pager_truncate_cache(pPager);
  }
  return rc;
}