Leaked source code of windows server 2003
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110 lines
2.8 KiB

/**************************************************************************
* SIGNAL.C
*
* Routines used to clean up on a forced KERNEL termination of a
* TOOLHELP using app.
*
**************************************************************************/
#include <string.h>
#include "toolpriv.h"
/* ----- Global variables ----- */
WORD wSignalInstalled;
SIGNAL NEAR *npSignalHead;
/* SignalRegister
* Registers a default signal proc to a task. This signal proc is
* called when the task is about to be terminated and is called before
* the USER signal proc is called. The registered callback is
* called HelperSignalProc() [HELPER.ASM] and chains to the USER signal
* proc (if any) instead of returning.
*/
BOOL PASCAL SignalRegister(
HANDLE hTask)
{
SIGNAL *pSig;
SIGNAL *pTemp;
/* NULL hTask means current task */
if (!hTask)
hTask = GetCurrentTask();
/* Check to see if this task is already registered */
for (pSig = npSignalHead ; pSig ; pSig = pSig->pNext)
if (pSig->hTask == hTask)
return FALSE;
/* Allocate a new SIGNAL structure */
pSig = (SIGNAL *)LocalAlloc(LMEM_FIXED, sizeof (SIGNAL));
if (!pSig)
return FALSE;
/* Fill in the useful fields */
pSig->hTask = hTask;
pSig->lpfn = (LPFNCALLBACK)HelperSignalProc;
pSig->lpfnOld = (LPFNCALLBACK)
HelperSetSignalProc(hTask, (DWORD)HelperSignalProc);
/* If this is the only handler, just insert it */
if (!npSignalHead)
{
pSig->pNext = npSignalHead;
npSignalHead = pSig;
}
/* Otherwise, insert at the end of the list */
else
{
for (pTemp = npSignalHead ; pTemp->pNext ; pTemp = pTemp->pNext)
;
pSig->pNext = pTemp->pNext;
pTemp->pNext = pSig;
}
return TRUE;
}
/* SignalUnRegister
* Called by an app whose callback is no longer to be used.
* NULL hTask uses current task.
*/
BOOL PASCAL SignalUnRegister(
HANDLE hTask)
{
SIGNAL *pSig;
SIGNAL *pBefore;
/* NULL hTask means current task */
if (!hTask)
hTask = GetCurrentTask();
/* First try to find the task */
pBefore = NULL;
for (pSig = npSignalHead ; pSig ; pSig = pSig->pNext)
if (pSig->hTask == hTask)
break;
else
pBefore = pSig;
if (!pSig)
return FALSE;
/* Remove it from the list */
if (!pBefore)
npSignalHead = pSig->pNext;
else
pBefore->pNext = pSig->pNext;
/* Replace the old signal proc */
HelperSetSignalProc(hTask, (DWORD)pSig->lpfnOld);
/* Free the structure */
LocalFree((HANDLE)pSig);
return TRUE;
}