A Device Driver for W2K Signals

Listing 3: signals.c — Source for signal DLL

#define STRICT 1
#include <windows.h>
#include <stdio.h>
#include <winioctl.h>
#include <string.h>
#include <stdlib.h>

#include "..\driver\sigdrv.h"
#define SIGNALSLIBAPI __declspec(dllexport)
#include "signals.h"

/* Global array of signal handler */
VOID (__stdcall *functable[MAX_SIGNALS])(VOID);

/* Handle to the device driver */
HANDLE hDevice;

/* Set a signal thread */
DWORD SetSignalHandler(DWORD SignalNumber, PVOID f)
{
   if (SignalNumber < MAX_SIGNALS)
   {
      functable[SignalNumber] = f;
      return 0;
   }
   return 1;
}

/* Call the appropriate signal handler */
DWORD WINAPI SignalsDriverRoutine(DWORD SignalNumber)
{
   if (functable[SignalNumber] != NULL)
      (functable[SignalNumber])();
   else
      printf("NULL signal function...!\n");

   return 0;
}


/* this information is sent to the device driver */
typedef struct _SIGINFO
{
   HANDLE   hThread;   /* target thread */
   ULONG    SigNo;     /* signal number */
   ULONG    SigFunc;   /* address of DriverRoutine */
} SIGINFO, *PSIGINFO;

SIGINFO     siginfo;

/* Send a signal to the targer thread */
DWORD SendSignalToThread(HANDLE hThread, DWORD SignalNumber)
{
   DWORD   cbReturned;

   /* Initialize a SIGINFO structure */
   siginfo.hThread = hThread;
   siginfo.SigNo = SignalNumber;
   siginfo.SigFunc = (unsigned long)SignalsDriverRoutine;

   /* Send the information to the driver */
   if (!DeviceIoControl (hDevice,
                         (DWORD)IOCTL_SIGDRV_SEND_SIGNAL,
                         (PSIGINFO) &siginfo,
                         sizeof(SIGINFO),
                         NULL,
                         0,
                         &cbReturned,
                         0
                         ) )
   {
      return 1;
   }
    return 0;
}

BOOL WINAPI DllMain(HINSTANCE hDllInst, DWORD fdwReason,
                    LPVOID lpvReserved)
{
   switch (fdwReason)
   {
      case DLL_PROCESS_ATTACH:
         if ((hDevice =
                CreateFile(
                  "\\\\.\\Global\\SIGDRV",
                  GENERIC_READ | GENERIC_WRITE,
                  FILE_SHARE_READ | FILE_SHARE_WRITE,
                  NULL,
                  OPEN_EXISTING,
                  FILE_ATTRIBUTE_NORMAL,
                  NULL
             )) == INVALID_HANDLE_VALUE)
         {
             printf ("Can't get a handle to the driver\n");
             return FALSE;
         }

         break;
      case DLL_PROCESS_DETACH:
           CloseHandle(hDevice);
         break;
      case DLL_THREAD_ATTACH:
         break;
      case DLL_THREAD_DETACH:
         break;
   }
   return TRUE;
}
 
/* End of File */