Module name: DeleteMe.cpp
Written by: Jeffrey Richter
Description: Allows an EXEcutable file to delete itself
********************************************************************/
#include <Windows.h>
#include <stdlib.h>
#include <tchar.h>
/////////////////////////////////////////////////////////////////////
int WINAPI WinMain(HINSTANCE h, HINSTANCE h2, LPSTR psz, int n) {
// Is this the Original EXE or the clone EXE?
// If the command-line 1 argument, this is the Original EXE
// If the command-line >1 argument, this is the clone EXE
if (__argc == 1) {
// Original EXE: Spawn clone EXE to delete this EXE
// Copy this EXEcutable image into the user's temp directory
TCHAR szPathOrig[_MAX_PATH], szPathClone[_MAX_PATH];
GetModuleFileName(NULL, szPathOrig, _MAX_PATH);
GetTempPath(_MAX_PATH, szPathClone);
GetTempFileName(szPathClone, __TEXT("Del"), 0, szPathClone);
CopyFile(szPathOrig, szPathClone, FALSE);
// Open the clone EXE using FILE_FLAG_DELETE_ON_CLOSE
HANDLE hfile = CreateFile(szPathClone, 0, FILE_SHARE_READ, NULL,
OPEN_EXISTING, FILE_FLAG_DELETE_ON_CLOSE, NULL);
// Spawn the clone EXE passing it our EXE's process handle
// and the full path name to the Original EXE file.
TCHAR szCmdLine[512];
HANDLE hProcessOrig = OpenProcess(SYNCHRONIZE, TRUE,
GetCurrentProcessId());
wsprintf(szCmdLine, __TEXT("%s %d \"%s\""), szPathClone, hProcessOrig,
szPathOrig);
STARTUPINFO si;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
PROCESS_INFORMATION pi;
CreateProcess(NULL, szCmdLine, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi);
CloseHandle(hProcessOrig);
CloseHandle(hfile);
// This original process can now terminate.
} else {
// Clone EXE: When original EXE terminates, delete it
HANDLE hProcessOrig = (HANDLE) _ttoi(__targv[1]);
WaitForSingleObject(hProcessOrig, INFINITE);
CloseHandle(hProcessOrig);
DeleteFile(__targv[2]);
// Insert code here to remove the subdirectory too (if desired).
// The system will delete the clone EXE automatically
// because it was opened with FILE_FLAG_DELETE_ON_CLOSE
}
return(0);
}
Figure 2 Coptex
Optex.h
/******************************************************************************
Module name: Optex.h
Written by: Jeffrey Richter
Purpose: Defines the COptex (optimized mutex) synchronization object
******************************************************************************/
#pragma once
///////////////////////////////////////////////////////////////////////////////
class COptex {
public:
COptex(LPCSTR pszName, DWORD dwSpinCount = 4000);
COptex(LPCWSTR pszName, DWORD dwSpinCount = 4000);
~COptex();
void SetSpinCount(DWORD dwSpinCount);
void Enter();
BOOL TryEnter();
void Leave();
private:
typedef struct {
DWORD m_dwSpinCount;
long m_lLockCount;
DWORD m_dwThreadId;
long m_lRecurseCount;
} SHAREDINFO, *PSHAREDINFO;
BOOL m_fUniprocessorHost;
HANDLE m_hevt;
HANDLE m_hfm;
PSHAREDINFO m_pSharedInfo;
private:
BOOL CommonConstructor(PVOID pszName, BOOL fUnicode, DWORD dwSpinCount);
};
///////////////////////////////////////////////////////////////////////////////
inline COptex::COptex(LPCSTR pszName, DWORD dwSpinCount) {
CommonConstructor((PVOID) pszName, FALSE, dwSpinCount);
}
///////////////////////////////////////////////////////////////////////////////
inline COptex::COptex(LPCWSTR pszName, DWORD dwSpinCount) {
CommonConstructor((PVOID) pszName, TRUE, dwSpinCount);
}
/******************************************************************************
Module name: Optex.cpp
Written by: Jeffrey Richter
Purpose: Implements the COptex (optimized mutex) synchronization object
******************************************************************************/
#include <windows.h>
#include "Optex.h"
///////////////////////////////////////////////////////////////////////////////
BOOL COptex::CommonConstructor(PVOID pszName, BOOL fUnicode, DWORD dwSpinCount)
{
m_hevt = m_hfm = NULL;
m_pSharedInfo = NULL;
SYSTEM_INFO sinf;
GetSystemInfo(&sinf);
m_fUniprocessorHost = (sinf.dwNumberOfProcessors == 1);
char szNameA[100];
if (fUnicode) { // Convert Unicode name to ANSI
wsprintfA(szNameA, "%S", pszName);
pszName = (PVOID) szNameA;
}
char sz[100];
wsprintfA(sz, "JMR_Optex_Event_%s", pszName);
m_hevt = CreateEventA(NULL, FALSE, FALSE, sz);
if (m_hevt != NULL) {
wsprintfA(sz, "JMR_Optex_MMF_%s", pszName);
m_hfm = CreateFileMappingA(NULL, NULL, PAGE_READWRITE, 0,
sizeof(*m_pSharedInfo), sz);
if (m_hfm != NULL) {
m_pSharedInfo = (PSHAREDINFO) MapViewOfFile(m_hfm, FILE_MAP_WRITE,
0, 0, 0);
// Note: SHAREDINFO's m_lLockCount, m_dwThreadId, and m_lRecurseCount
// members need to be initialized to 0. Fortunately, a new pagefile
// MMF sets all of its data to 0 when created. This saves us from
// some thread synchronization work.
if (m_pSharedInfo != NULL)
SetSpinCount(dwSpinCount);
}
}
return((m_hevt != NULL) && (m_hfm != NULL) && (m_pSharedInfo != NULL));
}
///////////////////////////////////////////////////////////////////////////////
COptex::~COptex() {
#ifdef _DEBUG
if (m_pSharedInfo->m_dwThreadId != 0) DebugBreak();
#endif
UnmapViewOfFile(m_pSharedInfo);
CloseHandle(m_hfm);
CloseHandle(m_hevt);
}
///////////////////////////////////////////////////////////////////////////////
void COptex::SetSpinCount(DWORD dwSpinCount) {
if (!m_fUniprocessorHost)
InterlockedExchange((PLONG) &m_pSharedInfo->m_dwSpinCount, dwSpinCount);
}
///////////////////////////////////////////////////////////////////////////////
void COptex::Enter() {
// Spin, trying to get the Optex
if (TryEnter()) return;
DWORD dwThreadId = GetCurrentThreadId(); // The calling thread's ID
if (InterlockedIncrement(&m_pSharedInfo->m_lLockCount) == 1) {
// Optex is unowned, let this thread own it once
InterlockedExchange((PLONG) &m_pSharedInfo->m_dwThreadId, dwThreadId);
m_pSharedInfo->m_lRecurseCount = 1;
} else {
// Optex is owned by a thread
if (m_pSharedInfo->m_dwThreadId == dwThreadId) {
// Optex is owned by this thread, own it again
m_pSharedInfo->m_lRecurseCount++;
} else {
// Optex is owned by another thread
// Wait for the Owning thread to release the Optex
WaitForSingleObject(m_hevt, INFINITE);
// We got ownership of the Optex
InterlockedExchange((PLONG) &m_pSharedInfo->m_dwThreadId,
dwThreadId); // We own it now
m_pSharedInfo->m_lRecurseCount = 1; // We own it once
}
}
}
///////////////////////////////////////////////////////////////////////////////
BOOL COptex::TryEnter() {
DWORD dwThreadId = GetCurrentThreadId(); // The calling thread's ID
// If the lock count is zero, the Optex is unowned and
// this thread can become the Owner of it now.
BOOL fThisThreadOwnsthe Optex = FALSE;
DWORD dwSpinCount = m_pSharedInfo->m_dwSpinCount;
do {
fThisThreadOwnsthe Optex = (0 == (DWORD)
InterlockedCompareExchange((PVOID*) &m_pSharedInfo->m_lLockCount,
(PVOID) 1, (PVOID) 0));
if (fThisThreadOwnsthe Optex) {
// We now own the Optex
InterlockedExchange((PLONG) &m_pSharedInfo->m_dwThreadId,
dwThreadId); // We own it
m_pSharedInfo->m_lRecurseCount = 1; // We own it once
} else {
// Some thread owns the Optex
if (m_pSharedInfo->m_dwThreadId == dwThreadId) {
// We already own the Optex
InterlockedIncrement(&m_pSharedInfo->m_lLockCount);
m_pSharedInfo->m_lRecurseCount++; // We own it again
fThisThreadOwnsthe Optex = TRUE; // Return that we own the Optex
}
}
} while (!fThisThreadOwnsthe Optex && (dwSpinCount-- > 0));
// Return whether or not this thread owns the Optex
return(fThisThreadOwnsthe Optex);
}
///////////////////////////////////////////////////////////////////////////////
void COptex::Leave() {
#ifdef _DEBUG
if (m_pSharedInfo->m_dwThreadId != GetCurrentThreadId())
DebugBreak();
#endif
if (--m_pSharedInfo->m_lRecurseCount > 0) {
// We still own the Optex
InterlockedDecrement(&m_pSharedInfo->m_lLockCount);
} else {
// We don't own the Optex
InterlockedExchange((PLONG) &m_pSharedInfo->m_dwThreadId, 0);
if (InterlockedDecrement(&m_pSharedInfo->m_lLockCount) > 0) {
// Other threads are waiting, wake one of the M
SetEvent(m_hevt);
}
}
}
/******************************************************************************
Module name: TestOptex.cpp
Written by: Jeffrey Richter
Purpose: A simple app that tests the COptex class
NOTE: Run multiple instances of this app to fully test the COptex
******************************************************************************/
#include <windows.h>
#include "Optex.h"
///////////////////////////////////////////////////////////////////////////////
#pragma data_seg("Shared")
int g_n= 0;
DWORD g_dw[1024] = { 0 };
#pragma data_seg()
#pragma comment(linker, "/section:Shared,rws")
///////////////////////////////////////////////////////////////////////////////
void main() {
COptex optex("TestOptex");
while (TRUE) {
optex.Enter();
if (g_n == 1024) { optex.Leave(); break; }
g_dw[g_n++] = GetCurrentProcessId();
optex.Leave();
}
GetLastError();
}