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SQLite training in Houston TX on 2019-11-05 (details)
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Overview
Comment:Prevent a rollback from crashing if the sector-size field of the rollback journal is corrupted. (CVS 5868)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: cf9d1d933f6b6713018928d9a7680ae63e8edcd0
User & Date: drh 2008-11-07 00:24:54
Context
2008-11-07
03:29
Prevent buffer overruns when converting malformed UTF16 to UTF8. Ticket #3482. (CVS 5869) check-in: 3f657e88 user: drh tags: trunk
00:24
Prevent a rollback from crashing if the sector-size field of the rollback journal is corrupted. (CVS 5868) check-in: cf9d1d93 user: drh tags: trunk
00:06
Add documentation to make it clear that short reads from xRead in the VFS must be zero-filled. (CVS 5867) check-in: fb311d6f user: drh 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 1.501 2008/11/03 20:55:07 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
  sqlite3_file *stfd;         /* File descriptor for the statement subjournal*/
  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
  i64 journalOff;             /* Current byte offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */
  i64 stmtHdrOff;             /* First journal header written this statement */
  i64 stmtCksum;              /* cksumInit when statement was started */
  i64 stmtJSize;              /* Size of journal at stmt_begin() */
  int sectorSize;             /* Assumed sector size during rollback */
#ifdef SQLITE_TEST
  int nHit, nMiss;            /* Cache hits and missing */
  int nRead, nWrite;          /* Database pages read/written */
#endif
  void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
#ifdef SQLITE_HAS_CODEC
  void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
................................................................................

  /* Update the assumed sector-size to match the value used by 
  ** the process that created this journal. If this journal was
  ** created by a process other than this one, then this routine
  ** is being called from within pager_playback(). The local value
  ** of Pager.sectorSize is restored at the end of that routine.
  */
  rc = read32bits(pPager->jfd, jrnlOff+12, (u32 *)&pPager->sectorSize);
  if( rc ) return rc;





  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
  return SQLITE_OK;
}


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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 1.502 2008/11/07 00:24:54 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
  sqlite3_file *stfd;         /* File descriptor for the statement subjournal*/
  BusyHandler *pBusyHandler;  /* Pointer to sqlite.busyHandler */
  i64 journalOff;             /* Current byte offset in the journal file */
  i64 journalHdr;             /* Byte offset to previous journal header */
  i64 stmtHdrOff;             /* First journal header written this statement */
  i64 stmtCksum;              /* cksumInit when statement was started */
  i64 stmtJSize;              /* Size of journal at stmt_begin() */
  u32 sectorSize;             /* Assumed sector size during rollback */
#ifdef SQLITE_TEST
  int nHit, nMiss;            /* Cache hits and missing */
  int nRead, nWrite;          /* Database pages read/written */
#endif
  void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
#ifdef SQLITE_HAS_CODEC
  void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
................................................................................

  /* Update the assumed sector-size to match the value used by 
  ** the process that created this journal. If this journal was
  ** created by a process other than this one, then this routine
  ** is being called from within pager_playback(). The local value
  ** of Pager.sectorSize is restored at the end of that routine.
  */
  rc = read32bits(pPager->jfd, jrnlOff+12, &pPager->sectorSize);
  if( rc ) return rc;
  if( (pPager->sectorSize & (pPager->sectorSize-1))!=0
         || pPager->sectorSize>0x1000000 ){
    return SQLITE_DONE;
  }

  pPager->journalOff += JOURNAL_HDR_SZ(pPager);
  return SQLITE_OK;
}


/*