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Ensure a database file is not truncated without an exclusive lock.

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Fix for ticket #1114. (CVS 2332)

FossilOrigin-Name: dcbc983355d3207615b52b0724405a024a1a5955
This commit is contained in:
danielk1977 2005-02-15 03:38:05 +00:00
parent 3c407374fc
commit 1722181328
3 changed files with 54 additions and 46 deletions
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12
manifest
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@ -1,5 +1,5 @@
C Check\sthat\sread-only\spages\sare\snot\sbeing\smodified\s(disabled\sby\sdefault).\s(CVS\s2331)
D 2005-02-15T02:54:15
C Ensure\sa\sdatabase\sfile\sis\snot\struncated\swithout\san\sexclusive\slock.\r\nFix\sfor\sticket\s#1114.\s(CVS\s2332)
D 2005-02-15T03:38:06
F Makefile.in d928187101fa3d78426cf48ca30e39d0fb714e57
F Makefile.linux-gcc a9e5a0d309fa7c38e7c14d3ecf7690879d3a5457
F README a01693e454a00cc117967e3f9fdab2d4d52e9bc1
@ -51,7 +51,7 @@ F src/os_unix.c 68d3d32937eee90fe1f50d500d1a4ee826cbe790
F src/os_unix.h f3097815e041e82e24d92505e1ff61ba24172d13
F src/os_win.c bddeae1c3299be0fbe47077dd4e98b786a067f71
F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
F src/pager.c 69efe972d6034d8d5603f5b2a768e43e25dad0c0
F src/pager.c 835028769569971c7dbd63d11d3517392f1cdae0
F src/pager.h 70d496f372163abb6340f474288c4bb9ea962cf7
F src/parse.y 450fc9c4d5a737be6fdba6e4b2e3de5800d4d750
F src/pragma.c 7e65c5545d83909238adf231e2a6eee6eb43e0d5
@ -271,7 +271,7 @@ F www/tclsqlite.tcl e73f8f8e5f20e8277619433f7970060ab01088fc
F www/vdbe.tcl 095f106d93875c94b47367384ebc870517431618
F www/version3.tcl 092a01f5ef430d2c4acc0ae558d74c4bb89638a0
F www/whentouse.tcl 3e522a06ad41992023c80ca29a048ae2331ca5bd
P cbed92f397ec13b57771ab8b5be74c0cacf35dfd
R f5e0bf334bc8ca4771ae6f5140466932
P 8514a4feb2a86e93c4251c491d394e861bb65edb
R 68447a9e1a1587fdc5cb563c6b34ab1f
U danielk1977
Z 79138fc5bf3ab18977a8db63dd8b495b
Z 2caaa7f8c9b8fb759f5bcfb478549a3f

2
manifest.uuid
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@ -1 +1 @@
8514a4feb2a86e93c4251c491d394e861bb65edb
dcbc983355d3207615b52b0724405a024a1a5955

86
src/pager.c
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@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.189 2005/02/15 02:54:15 danielk1977 Exp $
** @(#) $Id: pager.c,v 1.190 2005/02/15 03:38:06 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
@ -1137,6 +1137,7 @@ static int pager_reload_cache(Pager *pPager){
** indicated.
*/
static int pager_truncate(Pager *pPager, int nPage){
assert( pPager->state>=PAGER_EXCLUSIVE );
return sqlite3OsTruncate(&pPager->fd, pPager->pageSize*(i64)nPage);
}
@ -1256,7 +1257,8 @@ static int pager_playback(Pager *pPager){
/* If this is the first header read from the journal, truncate the
** database file back to it's original size.
*/
if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
if( pPager->state>=PAGER_EXCLUSIVE &&
pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
assert( pPager->origDbSize==0 || pPager->origDbSize==mxPg );
rc = pager_truncate(pPager, mxPg);
if( rc!=SQLITE_OK ){
@ -1354,10 +1356,11 @@ static int pager_stmt_playback(Pager *pPager){
hdrOff = szJ;
}
/* Truncate the database back to its original size.
*/
rc = pager_truncate(pPager, pPager->stmtSize);
if( pPager->state>=PAGER_EXCLUSIVE ){
rc = pager_truncate(pPager, pPager->stmtSize);
}
pPager->dbSize = pPager->stmtSize;
/* Figure out how many records are in the statement journal.
@ -1804,6 +1807,37 @@ static void memoryTruncate(Pager *pPager){
#define memoryTruncate(p)
#endif
/*
** Try to obtain a lock on a file. Invoke the busy callback if the lock
** is currently not available. Repeate until the busy callback returns
** false or until the lock succeeds.
**
** Return SQLITE_OK on success and an error code if we cannot obtain
** the lock.
*/
static int pager_wait_on_lock(Pager *pPager, int locktype){
int rc;
assert( PAGER_SHARED==SHARED_LOCK );
assert( PAGER_RESERVED==RESERVED_LOCK );
assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
if( pPager->state>=locktype ){
rc = SQLITE_OK;
}else{
int busy = 1;
do {
rc = sqlite3OsLock(&pPager->fd, locktype);
}while( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, busy++)
);
if( rc==SQLITE_OK ){
pPager->state = locktype;
}
}
return rc;
}
/*
** Truncate the file to the number of pages specified.
*/
@ -1826,6 +1860,13 @@ int sqlite3pager_truncate(Pager *pPager, Pgno nPage){
if( rc!=SQLITE_OK ){
return rc;
}
/* Get an exclusive lock on the database before truncating. */
rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
if( rc!=SQLITE_OK ){
return rc;
}
rc = pager_truncate(pPager, nPage);
if( rc==SQLITE_OK ){
pPager->dbSize = nPage;
@ -2057,37 +2098,6 @@ static int syncJournal(Pager *pPager){
return rc;
}
/*
** Try to obtain a lock on a file. Invoke the busy callback if the lock
** is currently not available. Repeate until the busy callback returns
** false or until the lock succeeds.
**
** Return SQLITE_OK on success and an error code if we cannot obtain
** the lock.
*/
static int pager_wait_on_lock(Pager *pPager, int locktype){
int rc;
assert( PAGER_SHARED==SHARED_LOCK );
assert( PAGER_RESERVED==RESERVED_LOCK );
assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
if( pPager->state>=locktype ){
rc = SQLITE_OK;
}else{
int busy = 1;
do {
rc = sqlite3OsLock(&pPager->fd, locktype);
}while( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, busy++)
);
if( rc==SQLITE_OK ){
pPager->state = locktype;
}
}
return rc;
}
/*
** Given a list of pages (connected by the PgHdr.pDirty pointer) write
** every one of those pages out to the database file and mark them all
@ -3072,13 +3082,11 @@ int sqlite3pager_rollback(Pager *pPager){
return pager_errcode(pPager);
}
if( pPager->state==PAGER_RESERVED ){
int rc2, rc3;
int rc2;
rc = pager_reload_cache(pPager);
rc2 = pager_truncate(pPager, pPager->origDbSize);
rc3 = pager_unwritelock(pPager);
rc2 = pager_unwritelock(pPager);
if( rc==SQLITE_OK ){
rc = rc2;
if( rc3 ) rc = rc3;
}
}else{
rc = pager_playback(pPager);