Understanding Process Creation in Windows and Unix Systems

1. Remote Process Explorer

2. Processes Windows • The Microsoft Windows NT operating system supports both models of process creation: • the parent's address space may be duplicated then the program be loaded into new address space, • or the parent may specify the name of a program for the operating system to load into the newly created address space at once. • In Windows CreateProcess() starts execution of the new process from the beginning • but in unix fork() starts execution after the point fork() was called. • there is no equivalent function for fork() in win32API. • The underlying API in Windows NT is certainly capable of performing a "fork“ • However, this is not exposed by the Win32 API. • So, you need to bypass Win32 and call the native API ({Nt|Zw}CreateProcess) • The book "Windows Nt/2000 Native Api Reference" has an example "Forking a Win32 Process".

3. Create Processes

4. Parent Process if(CreateProcess(".\\hello1.exe", NULL, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) { printf( "This is Parent, my PID=(%d): Creating Child1: PID=(%d)\n", _getpid(), pi.dwProcessId ); } else { printf( "CreateProcess1 failed (%d)\n", GetLastError() ); getch(); return; } if(CreateProcess(".\\hello2.exe", NULL, NULL, NULL, FALSE, 0, NULL, NULL, &sj, &pj)) { printf( "This is Parent, my PID=(%d): Creating Child2: PID=(%d)\n", _getpid(), pj.dwProcessId ); } else {printf( "CreateProcess2 failed (%d)\n", GetLastError() ); getch(); return; } // Wait until child processes exit. WaitForSingleObject( pi.hProcess, INFINITE ); WaitForSingleObject( pj.hProcess, INFINITE );

5. Child “Hello.exe”