/*
** Add an entry to the end of the write-list.
*/
static int writeListAppend(
sqlite3_file *pFile,
sqlite3_int64 iOffset,
const u8 *zBuf,
int nBuf
){
WriteBuffer *pNew;
assert((zBuf && nBuf) || (!nBuf && !zBuf));
pNew = (WriteBuffer *)crash_malloc(sizeof(WriteBuffer) + nBuf);
if( pNew==0 ){
fprintf(stderr, "out of memory in the crash simulator\n");
}
memset(pNew, 0, sizeof(WriteBuffer)+nBuf);
pNew->iOffset = iOffset;
pNew->nBuf = nBuf;
pNew->pFile = (CrashFile *)pFile;
if( zBuf ){
pNew->zBuf = (u8 *)&pNew[1];
memcpy(pNew->zBuf, zBuf, nBuf);
}
if( g.pWriteList ){
assert(g.pWriteListEnd);
g.pWriteListEnd->pNext = pNew;
}else{
g.pWriteList = pNew;
}
g.pWriteListEnd = pNew;
return SQLITE_OK;
}
/*
** Open a crash-file file handle.
**
** The caller will have allocated pVfs->szOsFile bytes of space
** at pFile. This file uses this space for the CrashFile structure
** and allocates space for the "real" file structure using
** sqlite3_malloc(). The assumption here is (pVfs->szOsFile) is
** equal or greater than sizeof(CrashFile).
*/
static int cfOpen(
sqlite3_vfs *pCfVfs,
const char *zName,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
int rc;
CrashFile *pWrapper = (CrashFile *)pFile;
sqlite3_file *pReal = (sqlite3_file*)&pWrapper[1];
memset(pWrapper, 0, sizeof(CrashFile));
rc = sqlite3OsOpen(pVfs, zName, pReal, flags, pOutFlags);
if( rc==SQLITE_OK ){
i64 iSize;
pWrapper->pMethod = &CrashFileVtab;
pWrapper->zName = (char *)zName;
pWrapper->pRealFile = pReal;
rc = sqlite3OsFileSize(pReal, &iSize);
pWrapper->iSize = (int)iSize;
pWrapper->flags = flags;
}
if( rc==SQLITE_OK ){
pWrapper->nData = (4096 + pWrapper->iSize);
pWrapper->zData = crash_malloc(pWrapper->nData);
if( pWrapper->zData ){
/* os_unix.c contains an assert() that fails if the caller attempts
** to read data from the 512-byte locking region of a file opened
** with the SQLITE_OPEN_MAIN_DB flag. This region of a database file
** never contains valid data anyhow. So avoid doing such a read here.
*/
const int isDb = (flags&SQLITE_OPEN_MAIN_DB);
i64 iChunk = pWrapper->iSize;
if( iChunk>PENDING_BYTE && isDb ){
iChunk = PENDING_BYTE;
}
memset(pWrapper->zData, 0, pWrapper->nData);
rc = sqlite3OsRead(pReal, pWrapper->zData, iChunk, 0);
if( SQLITE_OK==rc && pWrapper->iSize>(PENDING_BYTE+512) && isDb ){
i64 iOff = PENDING_BYTE+512;
iChunk = pWrapper->iSize - iOff;
rc = sqlite3OsRead(pReal, &pWrapper->zData[iOff], iChunk, iOff);
}
}else{
rc = SQLITE_NOMEM;
}
}
if( rc!=SQLITE_OK && pWrapper->pMethod ){
sqlite3OsClose(pFile);
}
return rc;
}
/*
** Open a crash-file file handle.
**
** The caller will have allocated pVfs->szOsFile bytes of space
** at pFile. This file uses this space for the CrashFile structure
** and allocates space for the "real" file structure using
** sqlite3_malloc(). The assumption here is (pVfs->szOsFile) is
** equal or greater than sizeof(CrashFile).
*/
static int cfOpen(
sqlite3_vfs *pCfVfs,
const char *zName,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
int rc;
CrashFile *pWrapper = (CrashFile *)pFile;
sqlite3_file *pReal = (sqlite3_file*)&pWrapper[1];
memset(pWrapper, 0, sizeof(CrashFile));
rc = sqlite3OsOpen(pVfs, zName, pReal, flags, pOutFlags);
if( rc==SQLITE_OK ){
i64 iSize;
pWrapper->pMethod = &CrashFileVtab;
pWrapper->zName = (char *)zName;
pWrapper->pRealFile = pReal;
rc = sqlite3OsFileSize(pReal, &iSize);
pWrapper->iSize = (int)iSize;
pWrapper->flags = flags;
}
if( rc==SQLITE_OK ){
pWrapper->nData = (int)(4096 + pWrapper->iSize);
pWrapper->zData = crash_malloc(pWrapper->nData);
if( pWrapper->zData ){
/* os_unix.c contains an assert() that fails if the caller attempts
** to read data from the 512-byte locking region of a file opened
** with the SQLITE_OPEN_MAIN_DB flag. This region of a database file
** never contains valid data anyhow. So avoid doing such a read here.
**
** UPDATE: It also contains an assert() verifying that each call
** to the xRead() method reads less than 128KB of data.
*/
i64 iOff;
memset(pWrapper->zData, 0, pWrapper->nData);
for(iOff=0; iOff<pWrapper->iSize; iOff += 512){
int nRead = (int)(pWrapper->iSize - iOff);
if( nRead>512 ) nRead = 512;
rc = sqlite3OsRead(pReal, &pWrapper->zData[iOff], nRead, iOff);
}
}else{
rc = SQLITE_NOMEM;
}
}
if( rc!=SQLITE_OK && pWrapper->pMethod ){
sqlite3OsClose(pFile);
}
return rc;
}
/*
** Open a crash-file file handle.
**
** The caller will have allocated pVfs->szOsFile bytes of space
** at pFile. This file uses this space for the CrashFile structure
** and allocates space for the "real" file structure using
** sqlite3_malloc(). The assumption here is (pVfs->szOsFile) is
** equal or greater than sizeof(CrashFile).
*/
static int cfOpen(
sqlite3_vfs *pCfVfs,
const char *zName,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
sqlite3_vfs *pVfs = (sqlite3_vfs *)pCfVfs->pAppData;
int rc;
CrashFile *pWrapper = (CrashFile *)pFile;
sqlite3_file *pReal = (sqlite3_file*)&pWrapper[1];
memset(pWrapper, 0, sizeof(CrashFile));
rc = sqlite3OsOpen(pVfs, zName, pReal, flags, pOutFlags);
if( rc==SQLITE_OK ){
i64 iSize;
pWrapper->pMethod = &CrashFileVtab;
pWrapper->zName = (char *)zName;
pWrapper->pRealFile = pReal;
rc = sqlite3OsFileSize(pReal, &iSize);
pWrapper->iSize = (int)iSize;
}
if( rc==SQLITE_OK ){
pWrapper->nData = (4096 + pWrapper->iSize);
pWrapper->zData = crash_malloc(pWrapper->nData);
if( pWrapper->zData ){
memset(pWrapper->zData, 0, pWrapper->nData);
rc = sqlite3OsRead(pReal, pWrapper->zData, pWrapper->iSize, 0);
}else{
rc = SQLITE_NOMEM;
}
}
if( rc!=SQLITE_OK && pWrapper->pMethod ){
sqlite3OsClose(pFile);
}
return rc;
}
/*
** Flush the write-list as if xSync() had been called on file handle
** pFile. If isCrash is true, simulate a crash.
*/
static int writeListSync(CrashFile *pFile, int isCrash){
int rc = SQLITE_OK;
int iDc = g.iDeviceCharacteristics;
WriteBuffer *pWrite;
WriteBuffer **ppPtr;
/* If this is not a crash simulation, set pFinal to point to the
** last element of the write-list that is associated with file handle
** pFile.
**
** If this is a crash simulation, set pFinal to an arbitrarily selected
** element of the write-list.
*/
WriteBuffer *pFinal = 0;
if( !isCrash ){
for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext){
if( pWrite->pFile==pFile ){
pFinal = pWrite;
}
}
}else if( iDc&(SQLITE_IOCAP_SEQUENTIAL|SQLITE_IOCAP_SAFE_APPEND) ){
int nWrite = 0;
int iFinal;
for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext) nWrite++;
sqlite3_randomness(sizeof(int), &iFinal);
iFinal = ((iFinal<0)?-1*iFinal:iFinal)%nWrite;
for(pWrite=g.pWriteList; iFinal>0; pWrite=pWrite->pNext) iFinal--;
pFinal = pWrite;
}
#ifdef TRACE_CRASHTEST
printf("Sync %s (is %s crash)\n", pFile->zName, (isCrash?"a":"not a"));
#endif
ppPtr = &g.pWriteList;
for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){
sqlite3_file *pRealFile = pWrite->pFile->pRealFile;
/* (eAction==1) -> write block out normally,
** (eAction==2) -> do nothing,
** (eAction==3) -> trash sectors.
*/
int eAction = 0;
if( !isCrash ){
eAction = 2;
if( (pWrite->pFile==pFile || iDc&SQLITE_IOCAP_SEQUENTIAL) ){
eAction = 1;
}
}else{
char random;
sqlite3_randomness(1, &random);
/* Do not select option 3 (sector trashing) if the IOCAP_ATOMIC flag
** is set or this is an OsTruncate(), not an Oswrite().
*/
if( (iDc&SQLITE_IOCAP_ATOMIC) || (pWrite->zBuf==0) ){
random &= 0x01;
}
/* If IOCAP_SEQUENTIAL is set and this is not the final entry
** in the truncated write-list, always select option 1 (write
** out correctly).
*/
if( (iDc&SQLITE_IOCAP_SEQUENTIAL && pWrite!=pFinal) ){
random = 0;
}
/* If IOCAP_SAFE_APPEND is set and this OsWrite() operation is
** an append (first byte of the written region is 1 byte past the
** current EOF), always select option 1 (write out correctly).
*/
if( iDc&SQLITE_IOCAP_SAFE_APPEND && pWrite->zBuf ){
i64 iSize;
sqlite3OsFileSize(pRealFile, &iSize);
if( iSize==pWrite->iOffset ){
random = 0;
}
}
if( (random&0x06)==0x06 ){
eAction = 3;
}else{
eAction = ((random&0x01)?2:1);
}
}
switch( eAction ){
case 1: { /* Write out correctly */
if( pWrite->zBuf ){
rc = writeDbFile(
pWrite->pFile, pWrite->zBuf, pWrite->nBuf, pWrite->iOffset
);
}else{
rc = sqlite3OsTruncate(pRealFile, pWrite->iOffset);
}
*ppPtr = pWrite->pNext;
#ifdef TRACE_CRASHTEST
if( isCrash ){
printf("Writing %d bytes @ %d (%s)\n",
pWrite->nBuf, (int)pWrite->iOffset, pWrite->pFile->zName
);
}
#endif
crash_free(pWrite);
break;
}
case 2: { /* Do nothing */
ppPtr = &pWrite->pNext;
#ifdef TRACE_CRASHTEST
if( isCrash ){
printf("Omiting %d bytes @ %d (%s)\n",
pWrite->nBuf, (int)pWrite->iOffset, pWrite->pFile->zName
);
}
#endif
break;
}
case 3: { /* Trash sectors */
u8 *zGarbage;
int iFirst = (int)(pWrite->iOffset/g.iSectorSize);
int iLast = (int)((pWrite->iOffset+pWrite->nBuf-1)/g.iSectorSize);
assert(pWrite->zBuf);
#ifdef TRACE_CRASHTEST
printf("Trashing %d sectors @ %lld (sector %d) (%s)\n",
1+iLast-iFirst, pWrite->iOffset, iFirst, pWrite->pFile->zName
);
#endif
zGarbage = crash_malloc(g.iSectorSize);
if( zGarbage ){
sqlite3_int64 i;
for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
sqlite3_randomness(g.iSectorSize, zGarbage);
rc = writeDbFile(
pWrite->pFile, zGarbage, g.iSectorSize, i*g.iSectorSize
);
}
crash_free(zGarbage);
}else{
rc = SQLITE_NOMEM;
}
ppPtr = &pWrite->pNext;
break;
}
default:
assert(!"Cannot happen");
}
if( pWrite==pFinal ) break;
}
if( rc==SQLITE_OK && isCrash ){
exit(-1);
}
for(pWrite=g.pWriteList; pWrite && pWrite->pNext; pWrite=pWrite->pNext);
g.pWriteListEnd = pWrite;
return rc;
}
