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Overview
Comment:Add a checksum to the master journal name stored at the end of a journal file. (CVS 1692)
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SHA1: 4905e74925a4e9d467c51dc174f265b9395ae9fa
User & Date: danielk1977 2004-06-25 11:11:54
Context
2004-06-25
12:08
Fix CVS merge problem. (CVS 1693) check-in: dfab1e9a user: danielk1977 tags: trunk
11:11
Add a checksum to the master journal name stored at the end of a journal file. (CVS 1692) check-in: 4905e749 user: danielk1977 tags: trunk
10:26
Remove crash.test from memleak.test. (CVS 1691) check-in: 2a9cea61 user: danielk1977 tags: trunk
Changes
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Changes to src/pager.c.

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** 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 1.141 2004/06/25 08:32:26 danielk1977 Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
** If no master journal file name is present *pzMaster is set to 0 and
** SQLITE_OK returned.
*/
static int readMasterJournal(OsFile *pJrnl, char **pzMaster){
  int rc;
  u32 len;
  off_t szJ;


  unsigned char aMagic[8]; /* A buffer to hold the magic header */

  *pzMaster = 0;

  rc = sqlite3OsFileSize(pJrnl, &szJ);
  if( rc!=SQLITE_OK || szJ<12 ) return rc;

  rc = sqlite3OsSeek(pJrnl, szJ-12);
  if( rc!=SQLITE_OK ) return rc;
 
  rc = read32bits(pJrnl, &len);
  if( rc!=SQLITE_OK ) return rc;




  rc = sqlite3OsRead(pJrnl, aMagic, 8);
  if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;

  rc = sqlite3OsSeek(pJrnl, szJ-12-len);
  if( rc!=SQLITE_OK ) return rc;

................................................................................
  }
  rc = sqlite3OsRead(pJrnl, *pzMaster, len);
  if( rc!=SQLITE_OK ){
    sqliteFree(*pzMaster);
    *pzMaster = 0;
    return rc;
  }









   
  return SQLITE_OK;
}

/*
** Seek the journal file descriptor to the next sector boundary where a
** journal header may be read or written. Pager.journalOff is updated with
................................................................................
  rc = sqlite3OsSeek(&pPager->jfd, pPager->journalOff);
  return rc;
}


/*
** Write the supplied master journal name into the journal file for pager
** pPager at the current location.












*/
static int writeMasterJournal(Pager *pPager, const char *zMaster){
  int rc;
  int len; 



  if( !zMaster || pPager->setMaster) return SQLITE_OK;
  pPager->setMaster = 1;

  len = strlen(zMaster);




  /* If in full-sync mode, advance to the next disk sector before writing
  ** the master journal name. This is in case the previous page written to
  ** the journal has already been synced.
  */
  if( pPager->fullSync ){
    rc = seekJournalHdr(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }

  pPager->journalOff += (len+16);

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

  rc = sqlite3OsWrite(&pPager->jfd, zMaster, len);
  if( rc!=SQLITE_OK ) return rc;

  rc = write32bits(&pPager->jfd, len);
  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







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** 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 1.142 2004/06/25 11:11:54 danielk1977 Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
** If no master journal file name is present *pzMaster is set to 0 and
** SQLITE_OK returned.
*/
static int readMasterJournal(OsFile *pJrnl, char **pzMaster){
  int rc;
  u32 len;
  off_t szJ;
  int cksum;
  int i;
  unsigned char aMagic[8]; /* A buffer to hold the magic header */

  *pzMaster = 0;

  rc = sqlite3OsFileSize(pJrnl, &szJ);
  if( rc!=SQLITE_OK || szJ<16 ) return rc;

  rc = sqlite3OsSeek(pJrnl, szJ-16);
  if( rc!=SQLITE_OK ) return rc;
 
  rc = read32bits(pJrnl, &len);
  if( rc!=SQLITE_OK ) return rc;

  rc = read32bits(pJrnl, &cksum);
  if( rc!=SQLITE_OK ) return rc;

  rc = sqlite3OsRead(pJrnl, aMagic, 8);
  if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;

  rc = sqlite3OsSeek(pJrnl, szJ-12-len);
  if( rc!=SQLITE_OK ) return rc;

................................................................................
  }
  rc = sqlite3OsRead(pJrnl, *pzMaster, len);
  if( rc!=SQLITE_OK ){
    sqliteFree(*pzMaster);
    *pzMaster = 0;
    return rc;
  }

  /* See if the checksum matches the master journal name */
  for(i=0; i<len; i++){
    cksum -= *pzMaster[i];
  }
  if( !cksum ){
    sqliteFree(*pzMaster);
    *pzMaster = 0;
  }
   
  return SQLITE_OK;
}

/*
** Seek the journal file descriptor to the next sector boundary where a
** journal header may be read or written. Pager.journalOff is updated with
................................................................................
  rc = sqlite3OsSeek(&pPager->jfd, pPager->journalOff);
  return rc;
}


/*
** Write the supplied master journal name into the journal file for pager
** pPager at the current location. The master journal name must be the last
** thing written to a journal file. If the pager is in full-sync mode, the
** journal file descriptor is advanced to the next sector boundary before
** anything is written. The format is:
**
** + 4 bytes: PAGER_MJ_PGNO.
** + N bytes: length of master journal name.
** + 4 bytes: N
** + 4 bytes: Master journal name checksum.
** + 8 bytes: aJournalMagic[].
**
** The master journal page checksum is the sum of the bytes in the master
** journal name.
*/
static int writeMasterJournal(Pager *pPager, const char *zMaster){
  int rc;
  int len; 
  int i; 
  int cksum = 0; 

  if( !zMaster || pPager->setMaster) return SQLITE_OK;
  pPager->setMaster = 1;

  len = strlen(zMaster);
  for(i=0; i<len; i++){
    cksum += zMaster[i];
  }

  /* If in full-sync mode, advance to the next disk sector before writing
  ** the master journal name. This is in case the previous page written to
  ** the journal has already been synced.
  */
  if( pPager->fullSync ){
    rc = seekJournalHdr(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }

  pPager->journalOff += (len+20);

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

  rc = sqlite3OsWrite(&pPager->jfd, zMaster, len);
  if( rc!=SQLITE_OK ) return rc;

  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