semaphor.c File Reference

#include <win32k.h>
#include <debug.h>

Include dependency graph for semaphor.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
	__drv_allocatesMem (Mem)
_Requires_lock_not_held_ hsem _Acquires_exclusive_lock_ hsem	_Acquires_lock_ (_Global_critical_region_)
_Requires_lock_held_ hsem _Releases_lock_ hsem	_Releases_lock_ (_Global_critical_region_)
_Requires_lock_not_held_ hsem VOID APIENTRY	EngDeleteSemaphore (_Inout_ __drv_freesMem(Mem) HSEMAPHORE hsem)
BOOL APIENTRY	EngIsSemaphoreOwned (_In_ HSEMAPHORE hsem)
BOOL APIENTRY	EngIsSemaphoreOwnedByCurrentThread (_In_ HSEMAPHORE hsem)
BOOL APIENTRY	EngInitializeSafeSemaphore (_Out_ ENGSAFESEMAPHORE *Semaphore)
VOID APIENTRY	EngDeleteSafeSemaphore (_Inout_ _Post_invalid_ ENGSAFESEMAPHORE *pssem)

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 3 of file semaphor.c.

Function Documentation

__drv_allocatesMem()

__drv_allocatesMem

(

Mem

)

Definition at line 9 of file semaphor.c.

{
    // www.osr.com/ddk/graphics/gdifncs_95lz.htm
    PERESOURCE psem = ExAllocatePoolWithTag(NonPagedPool,
                                            sizeof(ERESOURCE),
                                            GDITAG_SEMAPHORE);
    if (!psem)
        return NULL;
 
    if (!NT_SUCCESS(ExInitializeResourceLite(psem)))
    {
        ExFreePoolWithTag(psem, GDITAG_SEMAPHORE );
        return NULL;
    }
 
    return (HSEMAPHORE)psem;
}

_Acquires_lock_()

_Requires_lock_not_held_ hsem _Acquires_exclusive_lock_ hsem _Acquires_lock_

(

_Global_critical_region_

)

Definition at line 37 of file semaphor.c.

{
    // www.osr.com/ddk/graphics/gdifncs_14br.htm
    PTHREADINFO W32Thread;
 
    /* On Windows a NULL hsem is ignored */
    if (hsem == NULL)
    {
        DPRINT1("EngAcquireSemaphore called with hsem == NULL!\n");
        return;
    }
 
    ExEnterCriticalRegionAndAcquireResourceExclusive((PERESOURCE)hsem);
    W32Thread = PsGetThreadWin32Thread(PsGetCurrentThread());
    if (W32Thread) W32Thread->dwEngAcquireCount++;
}

_Releases_lock_()

_Requires_lock_held_ hsem _Releases_lock_ hsem _Releases_lock_

(

_Global_critical_region_

)

Definition at line 63 of file semaphor.c.

{
    // www.osr.com/ddk/graphics/gdifncs_5u3r.htm
    PTHREADINFO W32Thread;
 
    /* On Windows a NULL hsem is ignored */
    if (hsem == NULL)
    {
        DPRINT1("EngReleaseSemaphore called with hsem == NULL!\n");
        return;
    }
 
    W32Thread = PsGetThreadWin32Thread(PsGetCurrentThread());
    if (W32Thread) --W32Thread->dwEngAcquireCount;
    ExReleaseResourceAndLeaveCriticalRegion((PERESOURCE)hsem);
}

EngDeleteSafeSemaphore()

VOID APIENTRY EngDeleteSafeSemaphore

(

_Inout_ _Post_invalid_ ENGSAFESEMAPHORE *

pssem

)

Definition at line 181 of file semaphor.c.

{
    if (InterlockedDecrement(&pssem->lCount) == 0)
    {
        /* FIXME: Not thread-safe! Use result of InterlockedCompareExchangePointer! */
        EngDeleteSemaphore(pssem->hsem);
        (void)InterlockedExchangePointer((volatile PVOID *)&pssem->hsem, NULL);
    }
}

EngDeleteSemaphore()

_Requires_lock_not_held_ hsem VOID APIENTRY EngDeleteSemaphore

(

_Inout_ __drv_freesMem(Mem) HSEMAPHORE

hsem

)

Definition at line 106 of file semaphor.c.

{
    // www.osr.com/ddk/graphics/gdifncs_13c7.htm
    ASSERT(hsem);
 
    ExDeleteResourceLite((PERESOURCE)hsem);
    ExFreePoolWithTag((PVOID)hsem, GDITAG_SEMAPHORE);
}

Referenced by DdHmgCreate(), DdHmgDestroy(), DxDdCleanupDxGraphics(), DxDdStartupDxGraphics(), EngDeleteSafeSemaphore(), PDEVOBJ_vDeletePDEV(), Test_EngAcquireSemaphore(), Test_EngCreateSemaphore(), and Test_EngReleaseSemaphore().

EngInitializeSafeSemaphore()

BOOL APIENTRY EngInitializeSafeSemaphore

(

_Out_ ENGSAFESEMAPHORE *

Semaphore

)

Definition at line 147 of file semaphor.c.

{
    HSEMAPHORE hSem;
 
    if (InterlockedIncrement(&Semaphore->lCount) == 1)
    {
        /* Create the semaphore */
        hSem = EngCreateSemaphore();
        if (hSem == 0)
        {
            InterlockedDecrement(&Semaphore->lCount);
            return FALSE;
        }
        /* FIXME: Not thread-safe! Check result of InterlockedCompareExchangePointer
                  and delete semaphore if already initialized! */
        (void)InterlockedExchangePointer((volatile PVOID *)&Semaphore->hsem, hSem);
    }
    else
    {
        /* Wait for the other thread to create the semaphore */
        ASSERT(Semaphore->lCount > 1);
        ASSERT_IRQL_LESS_OR_EQUAL(PASSIVE_LEVEL);
        while (Semaphore->hsem == NULL);
    }
 
    return TRUE;
}

EngIsSemaphoreOwned()

BOOL APIENTRY EngIsSemaphoreOwned

(

_In_ HSEMAPHORE

hsem

)

Definition at line 121 of file semaphor.c.

{
    // www.osr.com/ddk/graphics/gdifncs_6wmf.htm
    ASSERT(hsem);
    return (((PERESOURCE)hsem)->ActiveCount > 0);
}

EngIsSemaphoreOwnedByCurrentThread()

BOOL APIENTRY EngIsSemaphoreOwnedByCurrentThread

(

_In_ HSEMAPHORE

hsem

)

Definition at line 134 of file semaphor.c.

{
    // www.osr.com/ddk/graphics/gdifncs_9yxz.htm
    ASSERT(hsem);
    return ExIsResourceAcquiredExclusiveLite((PERESOURCE)hsem);
}