操作系统 lab2 笔记

题目:

A "winPS" program: output information about all the running processes.
–output details about each process: such as PID, executable file name and path, etc.

A "kill" command: terminate processes.

Tips:
–Ref "CreateToolHelp32Snapshot", Process32First“, "Process32Next " & "TerminateProcess"

主要思路：对MSDN提供的样例代码进行改动。

1. 这儿tips给的太明显了，不查都不好意思了。一查第一个，就找到了样例代码（可做本实验的框架）。大概看了下剩下的几个。

2. 研究了一下样例代码（贴在最后），大概对win32的一些函数和机制有了了解。比如handle是干啥用的，几个主要函数的相互调用，几个宏定义的意义等。

下面开始改。

3. 样例代码跑了一次，该有的几乎都有了，主要是进程创建时间、在kernel里运行时间和在user space里运行的时间。

这个时间方面的实现用到了GerProcessTimes这个函数（上篇博文转载了），查了MSDN，后来百度几篇打得开的技术博文无果，果断FQ，开被墙掉的。尼玛一开就中，一篇好文坑爹 = =（事实证明有时不是百度渣，而是搜到了好东西都被墙掉了，勇敢地翻吧，少年...)照着国外大牛的代码捣鼓了一下，发现程序crash掉了。不奇怪，第一次嘛= =。看了看发现是在上面就把进程的handle给close掉了，擦，太渣了= =。果断调了下位置，在来一发，妈的，又crash...好吧，也很正常。发现crash之前warning输出了，OpenProcess failed. 这个就怪了，加了段时间有关的代码，怎么把进程都弄开不了了。于是乎凭直觉把时间的那段代码搬到了上面的else块里，在原先的CloseHandle( hProcess )之前。跑呗，无错~ 这错的就蛋疼了，看了好一会没找出来，之好放一边了。以后对windows编程理解更进一步的时候再回来看看！至少现在能跑了。= =

4. 接下来是文件流输出。因为都放在黑框框里，就只能看到最后那一丁点，所以还是导到文件里吧。C语言的文件流还是比较好用的。

嗯....慢着出了点问题。_tprintf( TEXT("\nPROCESS NAME: %s"), pe32.szExeFile );这货太有违和感了。问题在_tprintf和TEXT这。MSDN真的太给力了，一查，出来了。和条件编译有关（百科有）。大概就是，比如有char和wchar_t两种类型，但是我们不想时时刻刻在意到底现在这个变量是char还是wchar_t。如果编译器能帮我们搞定就最好了，好吧，果断能。这里_tprintf就自动对应printf或wprintf（wchar_t输出用），具体哪个你不用管。嗯，然后再查文件流输出相应的就OK了。接着是TEXT，也是个类似的东西。wchar_t的字符串要用L""来表示（char是""）。这里也是个转换的作用吧，我猜。

5. 文件流弄完了。剩下就是Kill进程。这个我觉得应该很水的。

唯一的问题在弄清上面条件编译的东西就好解决了。我之前主要是不知道怎么用wchar_t输入，现在一个_tscanf就搞定了。不用管对比的到底是wchar_t还是char，wcscmp可以解决。然后...就木有然后了。kill进程的时候输的进程名记得带.exe，靠，开始还以为出bug了，坑爹，挫= =。

下面是MSDN上的样例代码：

#include <windows.h>
#include <tlhelp32.h>
#include <tchar.h>
#include <stdio.h>

//  Forward declarations:
BOOL GetProcessList( );
BOOL ListProcessModules( DWORD dwPID );
BOOL ListProcessThreads( DWORD dwOwnerPID );
void printError( TCHAR* msg );

void main( )
{
  GetProcessList( );
}

BOOL GetProcessList( )
{
  HANDLE hProcessSnap;
  HANDLE hProcess;
  PROCESSENTRY32 pe32;
  DWORD dwPriorityClass;

  // Take a snapshot of all processes in the system.
  hProcessSnap = CreateToolhelp32Snapshot( TH32CS_SNAPPROCESS, 0 );
  if( hProcessSnap == INVALID_HANDLE_VALUE )
  {
    printError( TEXT("CreateToolhelp32Snapshot (of processes)") );
    return( FALSE );
  }

  // Set the size of the structure before using it.
  pe32.dwSize = sizeof( PROCESSENTRY32 );

  // Retrieve information about the first process,
  // and exit if unsuccessful
  if( !Process32First( hProcessSnap, &pe32 ) )
  {
    printError( TEXT("Process32First") ); // show cause of failure
    CloseHandle( hProcessSnap );          // clean the snapshot object
    return( FALSE );
  }

  // Now walk the snapshot of processes, and
  // display information about each process in turn
  do
  {
    printf( "\n\n=====================================================" );
    _tprintf( TEXT("\nPROCESS NAME:  %s"), pe32.szExeFile );
    printf( "\n-----------------------------------------------------" );

    // Retrieve the priority class.
    dwPriorityClass = 0;
    hProcess = OpenProcess( PROCESS_ALL_ACCESS, FALSE, pe32.th32ProcessID );
    if( hProcess == NULL )
      printError( TEXT("OpenProcess") );
    else
    {
      dwPriorityClass = GetPriorityClass( hProcess );
      if( !dwPriorityClass )
        printError( TEXT("GetPriorityClass") );
      CloseHandle( hProcess );
    }

    printf( "\n  Process ID        = 0x%08X", pe32.th32ProcessID );
    printf( "\n  Thread count      = %d",   pe32.cntThreads );
    printf( "\n  Parent process ID = 0x%08X", pe32.th32ParentProcessID );
    printf( "\n  Priority base     = %d", pe32.pcPriClassBase );
    if( dwPriorityClass )
      printf( "\n  Priority class    = %d", dwPriorityClass );

    // List the modules and threads associated with this process
    ListProcessModules( pe32.th32ProcessID );
    ListProcessThreads( pe32.th32ProcessID );

  } while( Process32Next( hProcessSnap, &pe32 ) );

  CloseHandle( hProcessSnap );
  return( TRUE );
}


BOOL ListProcessModules( DWORD dwPID )
{
  HANDLE hModuleSnap = INVALID_HANDLE_VALUE;
  MODULEENTRY32 me32;

  // Take a snapshot of all modules in the specified process.
  hModuleSnap = CreateToolhelp32Snapshot( TH32CS_SNAPMODULE, dwPID );
  if( hModuleSnap == INVALID_HANDLE_VALUE )
  {
    printError( TEXT("CreateToolhelp32Snapshot (of modules)") );
    return( FALSE );
  }

  // Set the size of the structure before using it.
  me32.dwSize = sizeof( MODULEENTRY32 );

  // Retrieve information about the first module,
  // and exit if unsuccessful
  if( !Module32First( hModuleSnap, &me32 ) )
  {
    printError( TEXT("Module32First") );  // show cause of failure
    CloseHandle( hModuleSnap );           // clean the snapshot object
    return( FALSE );
  }

  // Now walk the module list of the process,
  // and display information about each module
  do
  {
    _tprintf( TEXT("\n\n     MODULE NAME:     %s"),   me32.szModule );
    _tprintf( TEXT("\n     Executable     = %s"),     me32.szExePath );
    printf( "\n     Process ID     = 0x%08X",         me32.th32ProcessID );
    printf( "\n     Ref count (g)  = 0x%04X",     me32.GlblcntUsage );
    printf( "\n     Ref count (p)  = 0x%04X",     me32.ProccntUsage );
    printf( "\n     Base address   = 0x%08X", (DWORD) me32.modBaseAddr );
    printf( "\n     Base size      = %d",             me32.modBaseSize );

  } while( Module32Next( hModuleSnap, &me32 ) );

  CloseHandle( hModuleSnap );
  return( TRUE );
}

BOOL ListProcessThreads( DWORD dwOwnerPID ) 
{ 
  HANDLE hThreadSnap = INVALID_HANDLE_VALUE; 
  THREADENTRY32 te32; 
 
  // Take a snapshot of all running threads  
  hThreadSnap = CreateToolhelp32Snapshot( TH32CS_SNAPTHREAD, 0 ); 
  if( hThreadSnap == INVALID_HANDLE_VALUE ) 
    return( FALSE ); 
 
  // Fill in the size of the structure before using it. 
  te32.dwSize = sizeof(THREADENTRY32); 
 
  // Retrieve information about the first thread,
  // and exit if unsuccessful
  if( !Thread32First( hThreadSnap, &te32 ) ) 
  {
    printError( TEXT("Thread32First") ); // show cause of failure
    CloseHandle( hThreadSnap );          // clean the snapshot object
    return( FALSE );
  }

  // Now walk the thread list of the system,
  // and display information about each thread
  // associated with the specified process
  do 
  { 
    if( te32.th32OwnerProcessID == dwOwnerPID )
    {
      printf( "\n\n     THREAD ID      = 0x%08X", te32.th32ThreadID ); 
      printf( "\n     Base priority  = %d", te32.tpBasePri ); 
      printf( "\n     Delta priority = %d", te32.tpDeltaPri ); 
    }
  } while( Thread32Next(hThreadSnap, &te32 ) ); 

  CloseHandle( hThreadSnap );
  return( TRUE );
}

void printError( TCHAR* msg )
{
  DWORD eNum;
  TCHAR sysMsg[256];
  TCHAR* p;

  eNum = GetLastError( );
  FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
         NULL, eNum,
         MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
         sysMsg, 256, NULL );

  // Trim the end of the line and terminate it with a null
  p = sysMsg;
  while( ( *p > 31 ) || ( *p == 9 ) )
    ++p;
  do { *p-- = 0; } while( ( p >= sysMsg ) &&
                          ( ( *p == '.' ) || ( *p < 33 ) ) );

  // Display the message
  _tprintf( TEXT("\n  WARNING: %s failed with error %d (%s)"), msg, eNum, sysMsg );
}