/*
** 2008 Jan 22
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code for a VFS layer that acts as a wrapper around
** an existing VFS. The code in this file attempts to detect a specific
** bug in SQLite - writing data to a database file page when:
**
** a) the original page data is not stored in a synced portion of the
** journal file, and
** b) the page was not a free-list leaf page when the transaction was
** first opened.
**
** $Id: test_journal.c,v 1.3 2008/12/24 09:30:22 danielk1977 Exp $
*/
#if SQLITE_TEST /* This file is used for testing only */
#include "sqlite3.h"
#include "sqliteInt.h"
/*
** Maximum pathname length supported by the jt backend.
*/
#define JT_MAX_PATHNAME 512
/*
** Name used to identify this VFS.
*/
#define JT_VFS_NAME "jt"
typedef struct jt_file jt_file;
struct jt_file {
sqlite3_file base;
const char *zName; /* Name of open file */
int flags; /* Flags the file was opened with */
/* The following are only used by database file file handles */
int eLock; /* Current lock held on the file */
u32 nPage; /* Size of file in pages when transaction started */
u32 nPagesize; /* Page size when transaction started */
Bitvec *pWritable; /* Bitvec of pages that may be written to the file */
jt_file *pNext; /* All files are stored in a linked list */
sqlite3_file *pReal; /* The file handle for the underlying vfs */
};
/*
** Method declarations for jt_file.
*/
static int jtClose(sqlite3_file*);
static int jtRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int jtWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int jtTruncate(sqlite3_file*, sqlite3_int64 size);
static int jtSync(sqlite3_file*, int flags);
static int jtFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int jtLock(sqlite3_file*, int);
static int jtUnlock(sqlite3_file*, int);
static int jtCheckReservedLock(sqlite3_file*, int *);
static int jtFileControl(sqlite3_file*, int op, void *pArg);
static int jtSectorSize(sqlite3_file*);
static int jtDeviceCharacteristics(sqlite3_file*);
/*
** Method declarations for jt_vfs.
*/
static int jtOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int jtDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int jtAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int jtFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
#ifndef SQLITE_OMIT_LOAD_EXTENSION
static void *jtDlOpen(sqlite3_vfs*, const char *zFilename);
static void jtDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*jtDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void jtDlClose(sqlite3_vfs*, void*);
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
static int jtRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int jtSleep(sqlite3_vfs*, int microseconds);
static int jtCurrentTime(sqlite3_vfs*, double*);
static sqlite3_vfs jt_vfs = {
1, /* iVersion */
sizeof(jt_file), /* szOsFile */
JT_MAX_PATHNAME, /* mxPathname */
0, /* pNext */
JT_VFS_NAME, /* zName */
0, /* pAppData */
jtOpen, /* xOpen */
jtDelete, /* xDelete */
jtAccess, /* xAccess */
jtFullPathname, /* xFullPathname */
#ifndef SQLITE_OMIT_LOAD_EXTENSION
jtDlOpen, /* xDlOpen */
jtDlError, /* xDlError */
jtDlSym, /* xDlSym */
jtDlClose, /* xDlClose */
#else
0, /* xDlOpen */
0, /* xDlError */
0, /* xDlSym */
0, /* xDlClose */
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
jtRandomness, /* xRandomness */
jtSleep, /* xSleep */
jtCurrentTime /* xCurrentTime */
};
static sqlite3_io_methods jt_io_methods = {
1, /* iVersion */
jtClose, /* xClose */
jtRead, /* xRead */
jtWrite, /* xWrite */
jtTruncate, /* xTruncate */
jtSync, /* xSync */
jtFileSize, /* xFileSize */
jtLock, /* xLock */
jtUnlock, /* xUnlock */
jtCheckReservedLock, /* xCheckReservedLock */
jtFileControl, /* xFileControl */
jtSectorSize, /* xSectorSize */
jtDeviceCharacteristics /* xDeviceCharacteristics */
};
struct JtGlobal {
sqlite3_vfs *pVfs;
jt_file *pList;
};
static struct JtGlobal g = {0, 0};
static void closeTransaction(jt_file *p){
sqlite3BitvecDestroy(p->pWritable);
p->pWritable = 0;
}
/*
** Close an jt-file.
*/
static int jtClose(sqlite3_file *pFile){
jt_file **pp;
jt_file *p = (jt_file *)pFile;
if( p->zName ){
for(pp=&g.pList; *pp!=p; pp=&(*pp)->pNext);
*pp = p->pNext;
}
return sqlite3OsClose(p->pReal);
}
/*
** Read data from an jt-file.
*/
static int jtRead(
sqlite3_file *pFile,
void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
jt_file *p = (jt_file *)pFile;
return sqlite3OsRead(p->pReal, zBuf, iAmt, iOfst);
}
static jt_file *locateDatabaseHandle(const char *zJournal){
jt_file *pMain;
for(pMain=g.pList; pMain; pMain=pMain->pNext){
int nName = strlen(zJournal) - strlen("-journal");
if( (pMain->flags&SQLITE_OPEN_MAIN_DB)
&& (strlen(pMain->zName)==nName)
&& 0==memcmp(pMain->zName, zJournal, nName)
&& (pMain->eLock>=SQLITE_LOCK_RESERVED)
){
break;
}
}
return pMain;
}
static u32 decodeUint32(const unsigned char *z){
return (z[0]<<24) + (z[1]<<16) + (z[2]<<8) + z[3];
}
static int readFreelist(jt_file *pMain){
int rc;
sqlite3_file *p = pMain->pReal;
sqlite3_int64 iSize;
rc = sqlite3OsFileSize(p, &iSize);
if( rc==SQLITE_OK && iSize>=pMain->nPagesize ){
unsigned char *zBuf = (unsigned char *)malloc(pMain->nPagesize);
u32 iTrunk;
rc = sqlite3OsRead(p, zBuf, pMain->nPagesize, 0);
iTrunk = decodeUint32(&zBuf[32]);
while( rc==SQLITE_OK && iTrunk>0 ){
u32 nLeaf;
u32 iLeaf;
sqlite3_int64 iOff = (iTrunk-1)*pMain->nPagesize;
rc = sqlite3OsRead(p, zBuf, pMain->nPagesize, iOff);
nLeaf = decodeUint32(&zBuf[4]);
for(iLeaf=0; rc==SQLITE_OK && iLeaf<nLeaf; iLeaf++){
u32 pgno = decodeUint32(&zBuf[8+4*iLeaf]);
sqlite3BitvecSet(pMain->pWritable, pgno);
}
iTrunk = decodeUint32(zBuf);
}
free(zBuf);
}
return rc;
}
/*
** The first argument, zBuf, points to a buffer containing a 28 byte
** serialized journal header. This function deserializes four of the
** integer fields contained in the journal header and writes their
** values to the output variables.
*/
static int decodeJournalHdr(
const unsigned char *zBuf, /* Input: 28 byte journal header */
u32 *pnRec, /* Out: Number of journalled records */
u32 *pnPage, /* Out: Original database page count */
u32 *pnSector, /* Out: Sector size in bytes */
u32 *pnPagesize /* Out: Page size in bytes */
){
unsigned char aMagic[] = { 0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7 };
if( memcmp(aMagic, zBuf, 8) ) return 1;
if( pnRec ) *pnRec = decodeUint32(&zBuf[8]);
if( pnPage ) *pnPage = decodeUint32(&zBuf[16]);
if( pnSector ) *pnSector = decodeUint32(&zBuf[20]);
if( pnPagesize ) *pnPagesize = decodeUint32(&zBuf[24]);
return 0;
}
/*
** Write data to an jt-file.
*/
static int jtWrite(
sqlite3_file *pFile,
const void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
jt_file *p = (jt_file *)pFile;
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL && iOfst==0 ){
jt_file *pMain = locateDatabaseHandle(p->zName);
assert( pMain );
if( decodeJournalHdr(zBuf, 0, &pMain->nPage, 0, &pMain->nPagesize) ){
/* Zeroing the first journal-file header. This is the end of a
** transaction. */
closeTransaction(pMain);
}else{
/* Writing the first journal header to a journal file. This happens
** when a transaction is first started. */
int rc;
pMain->pWritable = sqlite3BitvecCreate(pMain->nPage);
if( !pMain->pWritable ){
return SQLITE_IOERR_NOMEM;
}
rc = readFreelist(pMain);
if( rc!=SQLITE_OK ){
return rc;
}
}
}
if( p->flags&SQLITE_OPEN_MAIN_DB && p->pWritable && iAmt==p->nPagesize ){
u32 pgno = iOfst/p->nPagesize + 1;
assert( pgno>p->nPage || sqlite3BitvecTest(p->pWritable, pgno) );
}
return sqlite3OsWrite(p->pReal, zBuf, iAmt, iOfst);
}
/*
** Truncate an jt-file.
*/
static int jtTruncate(sqlite3_file *pFile, sqlite_int64 size){
jt_file *p = (jt_file *)pFile;
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL && size==0 ){
/* Truncating a journal file. This is the end of a transaction. */
jt_file *pMain = locateDatabaseHandle(p->zName);
closeTransaction(pMain);
}
return sqlite3OsTruncate(p->pReal, size);
}
/*
** The first argument to this function is a handle open on a journal file.
** This function reads the journal file and adds the page number for each
** page in the journal to the Bitvec object passed as the second argument.
*/
static int readJournalFile(jt_file *p, jt_file *pMain){
int rc;
unsigned char zBuf[28];
sqlite3_file *pReal = p->pReal;
sqlite3_int64 iOff = 0;
sqlite3_int64 iSize = 0;
rc = sqlite3OsFileSize(p->pReal, &iSize);
while( rc==SQLITE_OK && iOff<iSize ){
u32 nRec, nPage, nSector, nPagesize;
u32 ii;
rc = sqlite3OsRead(pReal, zBuf, 28, iOff);
if( rc!=SQLITE_OK
|| decodeJournalHdr(zBuf, &nRec, &nPage, &nSector, &nPagesize)
){
return rc;
}
iOff += nSector;
if( nRec==0 ){
nRec = (iSize - iOff)/(pMain->nPagesize + 8);
}
for(ii=0; rc==SQLITE_OK && ii<nRec && iOff<iSize; ii++){
u32 pgno;
rc = sqlite3OsRead(pReal, zBuf, 4, iOff);
if( rc==SQLITE_OK ){
pgno = decodeUint32(zBuf);
iOff += (8 + pMain->nPagesize);
if( pgno>0 && pgno<=pMain->nPage ){
sqlite3BitvecSet(pMain->pWritable, pgno);
}
}
}
iOff = ((iOff + (nSector-1)) / nSector) * nSector;
}
return rc;
}
/*
** Sync an jt-file.
*/
static int jtSync(sqlite3_file *pFile, int flags){
jt_file *p = (jt_file *)pFile;
if( p->flags&SQLITE_OPEN_MAIN_JOURNAL ){
int rc;
jt_file *pMain; /* The associated database file */
/* The journal file is being synced. At this point, we inspect the
** contents of the file up to this point and set each bit in the
** jt_file.pWritable bitvec of the main database file associated with
** this journal file.
*/
pMain = locateDatabaseHandle(p->zName);
assert(pMain);
/* Set the bitvec values */
if( pMain->pWritable ){
rc = readJournalFile(p, pMain);
if( rc!=SQLITE_OK ){
return rc;
}
}
}
return sqlite3OsSync(p->pReal, flags);
}
/*
** Return the current file-size of an jt-file.
*/
static int jtFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
jt_file *p = (jt_file *)pFile;
return sqlite3OsFileSize(p->pReal, pSize);
}
/*
** Lock an jt-file.
*/
static int jtLock(sqlite3_file *pFile, int eLock){
int rc;
jt_file *p = (jt_file *)pFile;
rc = sqlite3OsLock(p->pReal, eLock);
if( rc==SQLITE_OK && eLock>p->eLock ){
p->eLock = eLock;
}
return rc;
}
/*
** Unlock an jt-file.
*/
static int jtUnlock(sqlite3_file *pFile, int eLock){
int rc;
jt_file *p = (jt_file *)pFile;
rc = sqlite3OsUnlock(p->pReal, eLock);
if( rc==SQLITE_OK && eLock<p->eLock ){
p->eLock = eLock;
}
return rc;
}
/*
** Check if another file-handle holds a RESERVED lock on an jt-file.
*/
static int jtCheckReservedLock(sqlite3_file *pFile, int *pResOut){
jt_file *p = (jt_file *)pFile;
return sqlite3OsCheckReservedLock(p->pReal, pResOut);
}
/*
** File control method. For custom operations on an jt-file.
*/
static int jtFileControl(sqlite3_file *pFile, int op, void *pArg){
jt_file *p = (jt_file *)pFile;
return sqlite3OsFileControl(p->pReal, op, pArg);
}
/*
** Return the sector-size in bytes for an jt-file.
*/
static int jtSectorSize(sqlite3_file *pFile){
jt_file *p = (jt_file *)pFile;
return sqlite3OsSectorSize(p->pReal);
}
/*
** Return the device characteristic flags supported by an jt-file.
*/
static int jtDeviceCharacteristics(sqlite3_file *pFile){
jt_file *p = (jt_file *)pFile;
return sqlite3OsDeviceCharacteristics(p->pReal);
}
/*
** Open an jt file handle.
*/
static int jtOpen(
sqlite3_vfs *pVfs,
const char *zName,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
int rc;
jt_file *p = (jt_file *)pFile;
p->pReal = (sqlite3_file *)&p[1];
p->pReal->pMethods = 0;
rc = sqlite3OsOpen(g.pVfs, zName, p->pReal, flags, pOutFlags);
assert( rc==SQLITE_OK || p->pReal->pMethods==0 );
if( rc==SQLITE_OK ){
pFile->pMethods = &jt_io_methods;
p->eLock = 0;
p->zName = zName;
p->flags = flags;
p->pNext = 0;
p->pWritable = 0;
if( zName ){
p->pNext = g.pList;
g.pList = p;
}
}
return rc;
}
/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.
*/
static int jtDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
int nPath = strlen(zPath);
if( nPath>8 && 0==strcmp("-journal", &zPath[nPath-8]) ){
/* Deleting a journal file. The end of a transaction. */
jt_file *pMain = locateDatabaseHandle(zPath);
if( pMain ){
closeTransaction(pMain);
}
}
return sqlite3OsDelete(g.pVfs, zPath, dirSync);
}
/*
** Test for access permissions. Return true if the requested permission
** is available, or false otherwise.
*/
static int jtAccess(
sqlite3_vfs *pVfs,
const char *zPath,
int flags,
int *pResOut
){
return sqlite3OsAccess(g.pVfs, zPath, flags, pResOut);
}
/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (JT_MAX_PATHNAME+1) bytes.
*/
static int jtFullPathname(
sqlite3_vfs *pVfs,
const char *zPath,
int nOut,
char *zOut
){
return sqlite3OsFullPathname(g.pVfs, zPath, nOut, zOut);
}
#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *jtDlOpen(sqlite3_vfs *pVfs, const char *zPath){
return sqlite3OsDlOpen(g.pVfs, zPath);
}
/*
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
** utf-8 string describing the most recent error encountered associated
** with dynamic libraries.
*/
static void jtDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
sqlite3OsDlError(g.pVfs, nByte, zErrMsg);
}
/*
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
*/
static void (*jtDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
return sqlite3OsDlSym(g.pVfs, p, zSym);
}
/*
** Close the dynamic library handle pHandle.
*/
static void jtDlClose(sqlite3_vfs *pVfs, void *pHandle){
sqlite3OsDlClose(g.pVfs, pHandle);
}
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
/*
** Populate the buffer pointed to by zBufOut with nByte bytes of
** random data.
*/
static int jtRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
return sqlite3OsRandomness(g.pVfs, nByte, zBufOut);
}
/*
** Sleep for nMicro microseconds. Return the number of microseconds
** actually slept.
*/
static int jtSleep(sqlite3_vfs *pVfs, int nMicro){
return sqlite3OsSleep(g.pVfs, nMicro);
}
/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int jtCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
return sqlite3OsCurrentTime(g.pVfs, pTimeOut);
}
int jt_register(char *zWrap, int isDefault){
g.pVfs = sqlite3_vfs_find(zWrap);
if( g.pVfs==0 ){
return SQLITE_ERROR;
}
jt_vfs.szOsFile += g.pVfs->szOsFile;
sqlite3_vfs_register(&jt_vfs, isDefault);
return SQLITE_OK;
}
void jt_unregister(){
sqlite3_vfs_unregister(&jt_vfs);
}
#endif