重复文件句柄，以避免共享冲突错误消息

我试图在增量备份系统上工作，当我运行我的脚本时，我总是得到“由于共享冲突无法打开文件”作为文件我试图打开做增量备份已被另一个进程使用。我知道我可以杀死这个进程，释放文件并进行增量备份，但这是我真正必须避免的。我读过Win32 API，我可以复制文件处理程序，所以我应该怎么做。重复文件句柄，以避免共享冲突错误消息

以下是一段我的代码：

FILE *GetFileHandle(WIN32_FIND_DATA *pWfdStruct, BOOL bWrite){ 

FILE *fFile; 
DWORD nGLE; 

fFile = fopen(pWfdStruct->cFileName, "rb"); 
if (!fFile) 
{ 
    nGLE = GetLastError(); 

    if (nGLE == ERROR_SHARING_VIOLATION) // 32 
    { 
     char szCurDir[8192]; 

     GetCurrentDirectory(8192, szCurDir); 
     ODS("WARN: cannot open %s file due to sharing violation [fRenameFile: %s\\%s]\n", 
      bWrite ? "dst" : "src", szCurDir, pWfdStruct->cFileName); 
     return 0; 
    } 

    if (nGLE == ERROR_ACCESS_DENIED)  // 5 
    { 
     char szCurDir[8192]; 

     GetCurrentDirectory(8192, szCurDir); 
     ODS("WARN: cannot open %s file, access denied [fRenameFile: %s\\%s]\n", 
      bWrite ? "dst" : "src", szCurDir, pWfdStruct->cFileName); 
     return 0; 
    } 

    if (nGLE == ERROR_FILE_NOT_FOUND)  // 2 
    { 
     char szCurDir[8192]; 

     GetCurrentDirectory(8192, szCurDir); 
     ODS("WARN: cannot open %s file, file not present [fRenameFile: %s\\%s]\n", 
      bWrite ? "dst" : "src", szCurDir, pWfdStruct->cFileName); 
     return 0; 
    } 

    char szCurDir[8192]; 
    GetCurrentDirectory(8192, szCurDir); 

    if (bWrite) 
    { 
     ODS("WARN: cannot open dst file [fRenameFile: %s\\%s] [GLE: %d]\n", 
      szCurDir, pWfdStruct->cFileName, nGLE); 
     return 0; 
    } 

    ODS("WARN: cannot open src file [fRenameFile: %s\\%s] [GLE: %d] trying alt name [%s]\n", 
     szCurDir, pWfdStruct->cFileName, nGLE, pWfdStruct->cAlternateFileName); 
    ReportSystemError("GetFileHandle", nGLE); 

    __try 
    { 
     if (pWfdStruct->cAlternateFileName[0]) 
     { 
      fFile = fopen(pWfdStruct->cAlternateFileName, "rb"); 
     } 
    } 
    __except(EXCEPTION_EXECUTE_HANDLER) 
    { 
     ODS("Exception caught\n"); // give up 
    } 

    if (!fFile) 
    { 
     nGLE = GetLastError(); 
     ReportSystemError("GetFileHandle 2nd try", nGLE); 
     FATALODS("FATAL error, cannot open src file [%s] [GLE: %d]", pWfdStruct->cFileName, nGLE); 
    } 
    else 
    { 
     ODS("File: %s open success\n", pWfdStruct->cAlternateFileName); 
    } 
} 
return fFile;} // GetFileHandle

你能帮帮我吗？

来源

2011-07-23 Bruno Andrade

如果该文件被另一个进程锁定，则无法将其打开。期。

Windows有专门用于构建备份客户端的Volume Shadow Copy服务（VSS）。它有复制锁定文件的规定，确保一致的快照等。API有点复杂，但如果您想要强大的备份解决方案，则没有其他办法。

有关使用VSS的示例，您可以查看开放源代码的HoboCopy备份工具。

编辑：经过一些谷歌搜索后，我发现了两个例子，做你想做的。我无法保证这些工作，但至少看起来似乎合理。

第一个例子，清晰和良好注释（语言是基本的一些方言，但很可读）：

$include "windowssdk.inc" 
$include "ntddk.inc" 
$include "undocumented.inc" 
$include "stdio.inc" 
$use "_crtdll.lib" 


'-------------------------- example 
$include "shlwapi.inc" 
$define REPLACE_ALWAYS 
' open youtube in internet explorer, watch any video (should be downloaded in 100%) 
' then run this program to copy the locked fla***.tmp file from your TEMP directory 
istring tmppath[MAX_PATH] 

' 1. enumerate fla*.tmp files in TEMP directory 
ExpandEnvironmentStrings("%TEMP%\\", tmppath, MAX_PATH) 
int pathlen = len(tmppath) 
strcpy(&tmppath[pathlen], "fla*.tmp") 
UINT hFind = findopen(tmppath) 
int nFilesFound = 0 
int nFilesCopied = 0 

if (hFind) 
    istring name[256] = findnext(hFind) 
    while (name[0] <> 0) 

     strncpy(&tmppath[pathlen], name, MAX_PATH-pathlen) 
     ' tmppath = local path to flash video 

     ' 2. copy the file with renamed extension (supported by media player classic) 
     istring newpath[MAX_PATH] 
     newpath = tmppath 
     PathRenameExtension(newpath, ".flv") 

     ' check if we can open the file directly 
     HANDLE hFile = CreateFile(tmppath, GENERIC_READ, FILE_SHARE_READ _ 
      | FILE_SHARE_WRITE | FILE_SHARE_DELETE, 0, OPEN_EXISTING, 0, 0) 

     if (hFile <> INVALID_HANDLE_VALUE) 
      ' file opened, so you can copy it with your favorite file manager 
      CloseHandle(hFile) 

     else 

      nFilesFound++ 
      ' the file is opened with exclusive access, call the subroutine below to open it 
      HANDLE hProcess 
      hFile = OpenFileEx(tmppath, &hProcess) 
      if (hFile = INVALID_HANDLE_VALUE) 
       ' failed 
       MessageBox 0, "failed to open " + tmppath, "" 
      else 
       ' copy it now ... 
$ifdef REPLACE_ALWAYS 
       HANDLE hOutFile = CreateFile(newpath, GENERIC_WRITE, 0, 0, CREATE_ALWAYS, 0, 0) 
$else 
       HANDLE hOutFile = CreateFile(newpath, GENERIC_WRITE, 0, 0, CREATE_NEW, 0, 0) 
$endif 
       if (hOutFile = INVALID_HANDLE_VALUE) 
        ' failed ? 
        MessageBox 0, "failed to create " + newpath, "" 
       else 
        ' ... but first suspend the owner process (because the handle is duplicated, and 
        ' if the owner process changes file pointer, it will be reflected also in this process) 
        declare import, NtSuspendProcess(HANDLE hProcess), NTSTATUS 
        declare import, NtResumeProcess(HANDLE hProcess), NTSTATUS 
        NtSuspendProcess(hProcess) 

        ' save original file pointer in originalFilePos variable 
        LARGE_INTEGER originalFilePos 
        LARGE_INTEGER nullFilePos 
        nullFilePos.QuadPart = 0q 
        SetFilePointerEx(hFile, nullFilePos, &originalFilePos, FILE_CURRENT) 

        ' seek to beginning 
        SetFilePointerEx(hFile, nullFilePos, NULL, FILE_BEGIN) 

        ' copy, using string name as the buffer 
        DWORD BytesRead, BytesWriten 
        while (ReadFile(hFile, &name, 256, &BytesRead, 0) and BytesRead) 
         WriteFile(hOutFile, name, BytesRead, &BytesWriten, 0) 
        endwhile 
        ' 
        nFilesCopied++ 
        ' restore file pointer 
        SetFilePointerEx(hFile, originalFilePos, NULL, FILE_BEGIN) 
        ' cleanup 
        CloseHandle(hOutFile) 
        ' resume the process 
        NtResumeProcess(hProcess) 
       endif 
       CloseHandle(hFile) 
      endif 
     endif 
     name = findnext(hFind) 
    endwhile 

    findclose(hFind) 
endif 

if (MessageBox(0, using("Copied # from # locked .FLV files. Open Directory ?", nFilesCopied, nFilesFound), "", MB_YESNO) = IDYES) 
    tmppath[pathlen-1] = 0 
    system tmppath 
endif 

'-------------------------- code 

type SYSTEM_HANDLE_ENTRY 
    ULONG OwnerPid 
    BYTE ObjectType 
    BYTE HandleFlags 
    USHORT HandleValue 
    PVOID ObjectPointer 
    ACCESS_MASK GrantedAccess 
endtype 

type SYSTEM_HANDLE_INFORMATION 
    ULONG HandleCount 
    SYSTEM_HANDLE_ENTRY Handles[1] 
endtype 

type MY_OBJECT_TYPE_INFORMATION 
    OBJECT_TYPE_INFORMATION t 
    iwstring buffer[64] 
endtype 

type MY_OBJECT_NAME_INFORMATION 
    OBJECT_NAME_INFORMATION t 
    iwstring buffer[280] 
endtype 

declare import, NtQuerySystemInformation(_ 
    int SystemInformationClass,_ 
    PVOID SystemInformation,_ 
    ULONG SystemInformationLength,_ 
    pointer ReturnLength),NTSTATUS 

const SystemHandleInformation = 16 




sub OpenFileEx(string path, pointer pphProcess),HANDLE 
    MY_OBJECT_TYPE_INFORMATION htype 
    MY_OBJECT_NAME_INFORMATION name 

    *<HANDLE>pphProcess = 0 
    HANDLE h = INVALID_HANDLE_VALUE 

    ' convert c:\ to \Device\HardDiskVolume... 
    ' 1. extract partition letter 
    iwstring root[4] 
    root[0] = path[0], 58, 0 
    ' 2. convert it to \Device\HardDiskVolumeX 
    iwstring wszNTPath[280] 
    int cch = QueryDosDeviceW(root, wszNTPath, 280) 
    if (!cch) then return INVALID_HANDLE_VALUE 
    ' 3. append remaining folders and file name from string path parameter 
    ' so <path> "c:\Program Files" gets converted to <wszNTPath> "\Device\HardDiskVolume1\Program Files" 
    cch = wcslen(wszNTPath) 
    _snwprintf(&wszNTPath[cch], 280-cch, L"%S", &path[2]) 
    ' now get the list of all handles, and find the handle which name is equal to wszNTPath 

    ULONG BytesNeeded, BufferSize = 4096 
    pointer handles = new(char, BufferSize) ' SYSTEM_HANDLE_INFORMATION* 

    while (handles) 

     ' get the list of all user-mode handles 
     NTSTATUS status = NtQuerySystemInformation(SystemHandleInformation, handles, BufferSize, &BytesNeeded) 
     if (status = STATUS_INFO_LENGTH_MISMATCH) 

      ' BytesNeeded is not adjusted, so we need to increase buffer size 
      delete handles 
      BufferSize += 32768 
      handles = new(char, BufferSize) 

     elseif (!status) 

      settype handles, SYSTEM_HANDLE_INFORMATION 
      ' sort handles by owning process id 
      qsort(&*handles.Handles, *handles.HandleCount, len(SYSTEM_HANDLE_ENTRY), &SortHandlesCb) 

      pointer node = *handles.Handles 
      settype node, SYSTEM_HANDLE_ENTRY 
      ULONG OwnerPid = 0 
      HANDLE hProcess = 0 
      HANDLE hThisProcess = GetCurrentProcess() 
      BYTE ObjectTypeFile = 0 

      while (*handles.HandleCount) 

       *handles.HandleCount-- 

       if (*node.GrantedAccess & FILE_READ_DATA) ' 13019F 

        if (OwnerPid <> *node.OwnerPid) 

         OwnerPid = *node.OwnerPid 
         if (hProcess) then CloseHandle(hProcess) 
         hProcess = OpenProcess(PROCESS_DUP_HANDLE|PROCESS_SUSPEND_RESUME, FALSE, OwnerPid) 

        endif 
        if (hProcess) 

         HANDLE hObject 
         if (DuplicateHandle(hProcess, *node.HandleValue, hThisProcess, &hObject, 0, FALSE, DUPLICATE_SAME_ACCESS)) 

          if (GetFileType(hObject) = FILE_TYPE_DISK) 

           if (!ObjectTypeFile) ' query object type name as "integer" 

            if (!NtQueryObject(hObject, ObjectTypeInformation, &htype, len(htype), &BytesNeeded)) 

             if (!_wcsnicmp(htype.t.TypeName.Buffer, L"File", 4)) 
              ObjectTypeFile = *node.ObjectType 
             endif 
            endif 
           endif 

           ' do not query object name with granted access 0x0012019f (deadloock) 
           if (ObjectTypeFile and (ObjectTypeFile = *node.ObjectType) and (*node.GrantedAccess <> 0x0012019f)) 

            ' query file name 
            if (!NtQueryObject(hObject, ObjectNameInformation, &name, len(name), &BytesNeeded)) 

             if (name.t.Name.Buffer and !wcsicmp(name.t.Name.Buffer, wszNTPath)) ' compare 

              *<HANDLE>pphProcess = hProcess 
              delete handles 
              return hObject 
             endif 
            endif 
           endif 
          endif 
          CloseHandle(hObject) 
         endif 
        endif 
       endif 
       node = &*node[1] 
      endwhile 
      if (hProcess) then CloseHandle(hProcess) 
      delete handles 

     else 
      ' NtQuerySystemInformation failed 
      delete handles 
     endif 

    endwhile 

    if (handles) then delete handles 
    return h 
endsub 


declare cdecl SortHandlesCb(SYSTEM_HANDLE_ENTRY p1, SYSTEM_HANDLE_ENTRY p2),int 

sub SortHandlesCb(SYSTEM_HANDLE_ENTRY p1, SYSTEM_HANDLE_ENTRY p2),int 
    if (p1.OwnerPid = p2.OwnerPid) then return 0 
    if (p1.OwnerPid > p2.OwnerPid) then return 1 
    return -1 
endsub

另一个凌乱的例子是在http://forum.sysinternals.com/topic7974.html。

请注意，这两个示例都使用Native API函数及其某些未公开的功能。

的基本步骤是：

获取文件句柄值被锁定过程观察。这通过调用NtQuerySystemInformation来获得系统中所有句柄的列表和NtQueryObject来找到具有匹配文件名的句柄。请注意，文件名必须转换为NT设备格式。
打开拥有拥有足够特权（PROCESS_DUP_HANDLE和PROCESS_SUSPEND_RESUME）的句柄（OpenProcess）并调用DuiplicateHandle（将该流程作为源，处理来自步骤1的值以及将流程作为目标）的过程。
使用NtSuspendProcess“暂停”进程并阻止它修改文件指针和文件内容）。
使用重复句柄复制文件。
恢复文件指针，关闭句柄，调用NtResumeProcess来取消暂停进程。

EDIT2：我个人已经用另一种方式来访问锁定的文件 - 带手动NTFS解析原始磁盘访问。例如。鉴于文件名称找到它的MFT条目，解码数据运行位置并从原始磁盘读取它们。原始磁盘访问始终可用（只要您具有管理员权限），因此任何文件都是可读的。缺点是零一致性保证，所以它不适合用于备份目的。

PS。如果我是你，我仍然会使用官方支持的VSS。备份软件不应该依赖黑客。

来源

2011-07-23 23:19:26

即使不使用fopen我使用CreateFile？ –

@布鲁诺你使用的任何方法。他们都最后调用CreateFile。 –

对不起，但我刚刚阅读有关duplicateHandle（），是否能够复制进程句柄，然后使我能够使用其他进程正在使用相同的文件？ –

重复文件句柄，以避免共享冲突错误消息

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