Leaked source code of windows server 2003
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/******************************************************************************
*
* Copyright (c) 2000 Microsoft Corporation
*
* Module Name:
* snappatch.cpp
*
* Abstract:
* functions for computing snapshot patch, and reconstructing snapshot from patch
*
* Revision History:
* Brijesh Krishnaswami (brijeshk) 03/22/2001
* created
*
*****************************************************************************/
#include "snapshoth.h"
#include "..\service\srconfig.h"
DWORD g_dwPatchWindow = 0xFFFFFFFF;
//
// get patch window
// 0 if patching is turned off
//
DWORD
PatchGetPatchWindow()
{
DWORD dwErr = ERROR_SUCCESS;
HKEY hKey = NULL;
tenter("PatchGetPatchWindow");
if (g_dwPatchWindow == 0xFFFFFFFF)
{
// uninitialized
// read from the registry
g_dwPatchWindow = 0;
if (ERROR_SUCCESS == RegOpenKeyEx(HKEY_LOCAL_MACHINE,
s_cszSRRegKey,
0,
KEY_READ,
&hKey))
{
RegReadDWORD(hKey, s_cszPatchWindow, &g_dwPatchWindow);
RegCloseKey(hKey);
}
trace(0, "Initializing g_dwPatchWindow = %ld", g_dwPatchWindow);
}
tleave();
return g_dwPatchWindow;
}
//
// get reference rp for a given rp
// RP1-RP10 -> reference is RP1
// RP11-RP20 -> reference is RP11 and so on
//
DWORD
PatchGetReferenceRpNum(
DWORD dwCurrentRp)
{
if (PatchGetPatchWindow() == 0)
return dwCurrentRp;
else
return (dwCurrentRp/PatchGetPatchWindow())*PatchGetPatchWindow() + 1;
}
DWORD
PatchGetReferenceRpPath(
DWORD dwCurrentRp,
LPWSTR pszRefRpPath)
{
tenter("PatchGetReferenceRpPath");
WCHAR szRp[MAX_RP_PATH], szSys[MAX_SYS_DRIVE]=L"";
DWORD dwRefRpNum = PatchGetReferenceRpNum(dwCurrentRp);
DWORD dwErr = ERROR_SUCCESS;
wsprintf(szRp, L"%s%ld", s_cszRPDir, dwRefRpNum);
GetSystemDrive(szSys);
MakeRestorePath(pszRefRpPath, szSys, szRp);
if (0xFFFFFFFF == GetFileAttributes(pszRefRpPath))
{
// RP directory does not exist -- it must've been fifoed
// try RefRP
trace(0, "Original rp does not exist -- trying RefRP");
wsprintf(szRp,L" %s%ld", s_cszReferenceDir, dwRefRpNum);
MakeRestorePath(pszRefRpPath, szSys, szRp);
if (0xFFFFFFFF == GetFileAttributes(pszRefRpPath))
{
// this does not exist either -- something wrong
trace(0, "RefRP does not exist either -- bailing");
dwErr = ERROR_NOT_FOUND;
goto Err;
}
}
trace(0, "Current Rp: %ld, Reference : %S", dwCurrentRp, pszRefRpPath);
Err:
tleave();
return dwErr;
}
//
// extract rp number from path
//
DWORD
PatchGetRpNumberFromPath(
LPCWSTR pszPath,
PDWORD pdwRpNum)
{
while (*pszPath != L'\0')
{
if (0 == wcsncmp(pszPath, s_cszRPDir, lstrlen(s_cszRPDir)))
{
pszPath += lstrlen(s_cszRPDir);
*pdwRpNum = _wtol(pszPath);
if (*pdwRpNum == 0)
continue;
else
return ERROR_SUCCESS;
}
pszPath++;
}
return ERROR_NOT_FOUND;
}
//
// compute the diff
//
DWORD
PatchComputePatch(
LPCWSTR pszCurrentDir)
{
tenter("PatchComputePatch");
DWORD dwErr = ERROR_SUCCESS;
WCHAR szTemp[MAX_PATH], szRef[MAX_PATH];
FILE* f = NULL;
DWORD dwCurRpNum;
// check if patching is turned off
if (PatchGetPatchWindow() == 0)
{
trace(0, "No patching");
goto Err;
}
// get the reference directory for this rp
CHECKERR(PatchGetRpNumberFromPath(pszCurrentDir, &dwCurRpNum),
L"PatchGetRpNumberFromPath");
CHECKERR(PatchGetReferenceRpPath(dwCurRpNum, szRef),
L"PatchGetReferenceRpPath");
// check if this directory is already patched
lstrcpy(szTemp, pszCurrentDir);
lstrcat(szTemp, L"\\");
lstrcat(szTemp, s_cszPatchCompleteMarker);
if (0xFFFFFFFF != GetFileAttributes(szTemp))
{
trace(0, "%S already patched", pszCurrentDir);
goto Err;
}
// call the library api to compute the patch
// this is a blocking call till the patching completes
// progress callback is used to terminate it
// PlaceHolder for library call (pszCurrentDir, szRef)
// check if we completed the patch successfully
// if so, then write a zero-byte file inside the directory to indicate this
lstrcpy(szTemp, pszCurrentDir);
lstrcat(szTemp, L"\\");
lstrcat(szTemp, s_cszPatchCompleteMarker);
f = (FILE *) _wfopen(szTemp, L"w");
if (!f)
{
dwErr = GetLastError();
trace(0, "! Cannot create %S : %ld", szTemp, dwErr);
goto Err;
}
fclose(f);
Err:
tleave();
return dwErr;
}
//
// patch progress callback
//
BOOL
PatchContinueCallback()
{
tenter("PatchContinueCallback");
BOOL fRc;
trace(0, "PatchContinueCallback called");
if (!g_pSRConfig)
{
trace(0, "g_pSRConfig = NULL -- terminating patch");
fRc = FALSE;
}
else if (IsStopSignalled(g_pSRConfig->m_hSRStopEvent))
{
trace(0, "Stop signalled -- terminating patch");
fRc = FALSE;
}
else
{
fRc = TRUE;
}
tleave();
return fRc;
}
//
// reconstruct the original
//
DWORD
PatchReconstructOriginal(
LPCWSTR pszCurrentDir,
LPWSTR pszDestDir)
{
tenter("PatchReconstructOriginal");
DWORD dwErr = ERROR_SUCCESS;
WCHAR szReferenceDir[MAX_PATH];
WCHAR szSys[MAX_SYS_DRIVE]=L"";
DWORD dwCurRpNum;
// check if patching is turned off
if (PatchGetPatchWindow() == 0)
{
trace(0, "No patching");
goto Err;
}
CHECKERR(PatchGetRpNumberFromPath(pszCurrentDir, &dwCurRpNum),
L"PatchGetRpNumberFromPath");
CHECKERR(PatchGetReferenceRpPath(dwCurRpNum, szReferenceDir),
L"PatchGetReferenceRpPath");
// call the library api to reconstruct the snapshot
// PlaceHolder for library call (pszCurrentDir, szReferenceDir, pszDestDir)
Err:
tleave();
return dwErr;
}