在我描述我的问题之前，这里是我正在编写的程序（IHExplorer.exe）的描述：
这是一个 C++ 应用程序。
IHExplorer 应用程序看起来尽可能像 Windows 资源管理器窗口。除了一个例外，从这个资源管理器窗口中启动文件将首先将它们解密到用户的临时文件夹，然后启动与文件扩展名关联的应用程序并在关闭时删除文件。
我遇到的问题是文件关闭时自动删除。这是一个场景：
- 用户在 IHExplorer 中双击一个加密的 .txt 文件。
IHExplorer 解密内存中的 .txt 文件，然后使用 ::CreateFile 将其写入 %TEMP%，该文件返回文件的句柄（IHExplorer 必须保持此句柄至少打开，直到 .txt 文件被 shell 执行）。
IHExplorer Shell 从其临时位置执行 .txt 文件（通过调用 ::ShellExecute）。
- 现在 IHExplorer 和记事本都有打开文件的句柄。
- 当 IHExplorer 和记事本都关闭了文件的句柄时，必须自动删除该文件，即使 IHExplorer 先关闭也是如此。
行。这是一个基本的用户案例，描述了我想要发生的事情。我遇到的问题是当我 ::ShellExecute() 时，记事本说“该进程无法访问该文件，因为它正在被另一个进程使用。” （这将是 IHExplorer）。我需要解决这个问题并让记事本打开它，即使我仍然在 IHExplorer 中打开了句柄。
这是我对 ::CreateFile 的调用如下所示：
DWORD dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
DWORD dwFlagsAndAttributes = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE;
HANDLE hFile = ::CreateFile(strTempFile.c_str(), GENERIC_WRITE, dwShareMode, &sa, CREATE_NEW, dwFlagsAndAttributes, NULL);
请注意，我使用了 FILE_SHARE_DELETE 以便其他进程（例如记事本）可以使用删除权限打开文件。
请注意，我使用了 FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE 属性指示文件是临时文件，应在关闭时删除。
还要注意 &sa 参数。这是我正在使用的 SECURITY_ATTRIBUTES 结构，我觉得（希望）这就是我的问题所在。这是代码，这次我将发布整个函数，以便您查看我如何填写 SECURITY_ATTRIBUTES 结构：
int CIHExplorerDoc::OpenFile(std::string strFileName, bool bIsFullPath) {
std::string strFullFilePath;
if(bIsFullPath) {
strFullFilePath = strFileName;
strFileName = IHawk::RemovePath(strFileName);
}else {
strFullFilePath = m_strDirectory + strFileName;
}
if(!HasEncryptionFileExtension(strFullFilePath)) {
LaunchFile(strFullFilePath);
}else {
//it's an encrypted file, so open it and copy unencrypted file to temp.
IHawk::EncryptedFileHandle hEncryptedFile(strFullFilePath.c_str(), true, theApp.GetKeyServer());
if(hEncryptedFile.IsValid()) {
std::string strTempFile = g_strTempFolder + IHawk::ChangeFileExtension(strFileName, "");
//TODO: Determine what the LPSECURITY_ATTRIBUTES should be.
SECURITY_ATTRIBUTES sa;
SECURITY_DESCRIPTOR sd;
if(!InitializeSecurityDescriptor(&sd,SECURITY_DESCRIPTOR_REVISION)) {
DWORD dwLastError = ::GetLastError();
LOG4CPLUS_ERROR(m_Logger, "Cannot launch file '" << strFullFilePath << "'. Failed to initialize security descriptor. GetLastError=" << dwLastError);
return dwLastError;
}
if(!SetSecurityDescriptorDacl(
&sd, // A pointer to the SECURITY_DESCRIPTOR structure to which the function adds the DACL
TRUE, // presence of a DACL in the security descriptor
NULL, // allows all access to the object
FALSE // DACL has been explicitly specified by a user
))
{
DWORD dwLastError = ::GetLastError();
LOG4CPLUS_ERROR(m_Logger, "Cannot launch file '" << strFullFilePath << "'. Failed to set security descriptor DACL. GetLastError=" << dwLastError);
return dwLastError;
}
if(!SetSecurityDescriptorGroup(
&sd, // A pointer to the SECURITY_DESCRIPTOR structure whose primary group is set by this function
NULL, // no primary group
FALSE // Indicates whether the primary group information was derived from a default mechanism
))
{
DWORD dwLastError = ::GetLastError();
LOG4CPLUS_ERROR(m_Logger, "Cannot launch file '" << strFullFilePath << "'. Failed to set security descriptor primary group. GetLastError=" << dwLastError);
return dwLastError;
}
if(!SetSecurityDescriptorOwner(
&sd, // A pointer to the SECURITY_DESCRIPTOR structure whose owner is set by this function.
NULL, // If this parameter is NULL, the function clears the security descriptor's owner information. This marks the security descriptor as having no owner.
FALSE // Indicates whether the owner information is derived from a default mechanism.
))
{
DWORD dwLastError = ::GetLastError();
LOG4CPLUS_ERROR(m_Logger, "Cannot launch file '" << strFullFilePath << "'. Failed to set security descriptor owner information. GetLastError=" << dwLastError);
return dwLastError;
}
if(!SetSecurityDescriptorSacl(
&sd, // A pointer to the SECURITY_DESCRIPTOR structure to which the function adds the SACL
FALSE, // the security descriptor does not contain a SACL
NULL, // security descriptor has a NULL SACL
FALSE // A pointer to a flag that is set to the value of the SE_SACL_DEFAULTED flag in the SECURITY_DESCRIPTOR_CONTROL structure if a SACL exists for the security descriptor
))
{
DWORD dwLastError = ::GetLastError();
LOG4CPLUS_ERROR(m_Logger, "Cannot launch file '" << strFullFilePath << "'. Failed to set security descriptor SACL. GetLastError=" << dwLastError);
return dwLastError;
}
sa.nLength = sizeof(SECURITY_ATTRIBUTES);
sa.lpSecurityDescriptor = &sd;
sa.bInheritHandle = TRUE;
DWORD dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
// DWORD dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
DWORD dwFlagsAndAttributes = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE;
HANDLE hFile = ::CreateFile(strTempFile.c_str(), GENERIC_WRITE, dwShareMode, &sa, CREATE_NEW, dwFlagsAndAttributes, NULL);
//verify we created the file.
if(hFile == INVALID_HANDLE_VALUE) {
DWORD dwLastError = ::GetLastError();
return dwLastError;
}
//copy to temp
char buffer[64*1024];
size_t nBytesRead = hEncryptedFile.Read(buffer, sizeof(buffer));
while(nBytesRead) {
DWORD numBytesWritten;
if(!::WriteFile(hFile, buffer, nBytesRead, &numBytesWritten, (LPOVERLAPPED) NULL)) {
DWORD dwLastError = ::GetLastError();
LOG4CPLUS_ERROR(m_Logger, "Failed to write file to %TEMP% folder. GetLastError=" << dwLastError);
return dwLastError;
}
nBytesRead = hEncryptedFile.Read(buffer, sizeof(buffer));
}
hEncryptedFile.Close();
//execute the file from temp.
LaunchFile(strTempFile);
}
}
return 0;
}
我想如果我确定正确的 SECURITY_DESCRIPTOR 传递给 ::CreateFile 它可能会像我想要的那样工作。请帮忙。
顺便说一句，LaunchFile 函数最终只是调用 ::ShellExecute 来启动文件。