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Make sure the dbFileVers field in the Pager object is properly initialized

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even if there is an I/O error while reading its content off of disk.

FossilOrigin-Name: 81ff698f62c8133818a3db1997ae7427705da23f
This commit is contained in:
drh
2010-03-05 20:17:45 +00:00
parent 5fea90762a
commit 29391c5b49
3 changed files with 37 additions and 10 deletions
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21
src/pager.c
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@@ -3339,6 +3339,7 @@ int sqlite3PagerOpen(
/* pPager->pBusyHandlerArg = 0; */
pPager->xReiniter = xReinit;
/* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
*ppPager = pPager;
return SQLITE_OK;
}
@@ -3488,8 +3489,24 @@ static int readDbPage(PgHdr *pPg){
rc = SQLITE_OK;
}
if( pgno==1 ){
u8 *dbFileVers = &((u8*)pPg->pData)[24];
memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
if( rc ){
/* If the read is unsuccessful, set the dbFileVers[] to something
** that will never be a valid file version. dbFileVers[] is a copy
** of bytes 24..39 of the database. Bytes 28..31 should always be
** zero. Bytes 32..35 and 35..39 should be page numbers which are
** never 0xffffffff. So filling pPager->dbFileVers[] with all 0xff
** bytes should suffice.
**
** For an encrypted database, the situation is more complex: bytes
** 24..39 of the database are white noise. But the probability of
** white noising equaling 16 bytes of 0xff is vanishingly small so
** we should still be ok.
*/
memset(pPager->dbFileVers, 0xff, sizeof(pPager->dbFileVers));
}else{
u8 *dbFileVers = &((u8*)pPg->pData)[24];
memcpy(&pPager->dbFileVers, dbFileVers, sizeof(pPager->dbFileVers));
}
}
CODEC1(pPager, pPg->pData, pgno, 3, rc = SQLITE_NOMEM);